1
|
Guo M, Zhao Z, Xie Z, Wu W, Wu W, Gao Q. Role of the Branched PEG- b-PLLA Block Chain in Stereocomplex Crystallization and Crystallization Kinetics for PDLA/MPEG- b-PLLA- g-glucose Blends with Different Architectures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15866-15879. [PMID: 36469019 DOI: 10.1021/acs.langmuir.2c02867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The isothermal crystallization behavior and corresponding morphology evolution of poly(d-lactic acid) (PDLA) blends with PLLA6.7k or MPEG-b-PLLA6.7k-g-glucose with different architectures and different PLLA-grafted copolymer contents were investigated. The formation of stereocomplexes (SCs) in between the chain branched structure of MPEG-b-PLLA6.7k-g-glucose and PDLA chains acting as the physical crosslinking points slows down the motion of PDLA chains, but the SCs could act as a heterogeneous nucleating agent for the late formation of homocrystals (HCs) in the blend system, accelerating the crystallization kinetics of HCs through enhancing the nucleation density. For PDLA/MPEG-b-PLLA6.7k-g-glucose blends, the mobility of SCs in the blend system and the nucleation density of SCs in the blends exhibit oppositional behavior during the isothermal crystallization at a Tc of 130 °C. The evolution of the crystal growth and structure during the isothermal crystallization process by rheometry has revealed the interesting role of the branched chains of MPEG-b-PLLA6.7k-g-glucose in the mechanism of the crystallization in PDLA blends.
Collapse
Affiliation(s)
- Mingwei Guo
- College of Chemical Engineering, Nanjing Forestry University, Nanjing210037, China
| | - Zhifeng Zhao
- College of Chemical Engineering, Hebei University of Technology, Tianjin300130, China
| | - Zhongyuan Xie
- College of Chemical Engineering, Nanjing Forestry University, Nanjing210037, China
| | - Weixin Wu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing210037, China
| | - Wenjing Wu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing210037, China
| | - Qinwei Gao
- College of Chemical Engineering, Nanjing Forestry University, Nanjing210037, China
- Jiangsu Key Lab for the Chemistry and Utilization of Agricultural and Forest Biomass, Nanjing Forestry University, Nanjing210037, China
| |
Collapse
|
2
|
Gu Z, Zhang J, Cao W, Liu X, Wang J, Zhang X, Chen W, Bao J. Extraordinary toughness and heat resistance enhancement of biodegradable PLA/PBS blends through the formation of a small amount of interface-localized stereocomplex crystallites during melt blending. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
3
|
Ladelta V, Ntetsikas K, Zapsas G, Hadjichristidis N. Non-Covalent PS–SC–PI Triblock Terpolymers via Polylactide Stereocomplexation: Synthesis and Thermal Properties. Macromolecules 2022. [DOI: 10.1021/acs.macromol.1c02294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Viko Ladelta
- Physical Sciences and Engineering Division, KAUST Catalysis Center, Polymer Synthesis Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Konstantinos Ntetsikas
- Physical Sciences and Engineering Division, KAUST Catalysis Center, Polymer Synthesis Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - George Zapsas
- Physical Sciences and Engineering Division, KAUST Catalysis Center, Polymer Synthesis Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Nikos Hadjichristidis
- Physical Sciences and Engineering Division, KAUST Catalysis Center, Polymer Synthesis Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| |
Collapse
|
4
|
Tungsten disulfide nanotubes enhance flow-induced crystallization and radio-opacity of polylactide without adversely affecting in vitro toxicity. Acta Biomater 2022; 138:313-326. [PMID: 34798318 PMCID: PMC9505057 DOI: 10.1016/j.actbio.2021.11.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/17/2021] [Accepted: 11/04/2021] [Indexed: 01/17/2023]
Abstract
Treatment of vascular disease, from peripheral ischemia to coronary heart disease (CHD), is poised for transformation with the introduction of transient implants designed to "scaffold" regeneration of blood vessels and ultimately leave nothing behind. Improved materials could expand the use of these devices. Here, we examine one of the leading polymers for bioresorbable scaffolds (BRS), polylactide (PLA), as the matrix of nanocomposites with tungsten disulfide (WS2) nanotubes (WSNT), which may provide mechanical reinforcement and enhance radio-opacity. We evaluate in vitro cytotoxicity using vascular cells, flow-induced crystallization and radio-opacity of PLA-WSNT nanocomposites at low WSNT concentration. A small amount of WSNT (0.1 wt%) can effectively promote oriented crystallization of PLA without compromising molecular weight. And radio-opacity improves significantly: as little as 0.5 to 1 wt% WSNT doubles the radio-opacity of PLA-WSNT relative to PLA at 17 keV. The results suggest that a single component, WSNT, has the potential to increase the strength of BRS to enable thinner devices and increase radio-opacity to improve intraoperative visualization. The in vitro toxicity results indicate that PLA-WSNT nanocomposites are worthy of investigation in vivo. Although substantial further preclinical studies are needed, PLA-WSNT nanocomposites may provide a complement of material properties that may improve BRS and expand the range of lesions that can be treated using transient implants. STATEMENT OF SIGNIFICANCE: Bioresorbable Scaffolds (BRSs) support regeneration of arteries without permanent mechanical constraint. Poly-L-lactide (PLLA) is the structural material of the first approved BRS for coronary heart disease (ABSORB BVS), withdrawn due to adverse events in years 1-3. Here, we examine tungsten disulfide (WS2) nanotubes (WSNT) in PLA to address two contributors to early complications: (1) reinforce PLLA (enable thinner BRS), and (2) increase radiopacity (provide intraoperative visibility). For BRS, it is significant that WSNT disperse, remain dispersed, reduce friction and improve mechanical properties without additional chemicals or surface modifications. Like WS2 nanospheres, bare WSNT and PLA-WSNT nanocomposites show low cytotoxicity in vitro. PLA-WSNT show enhanced flow-induced crystallization relative to PLA, motivating future study of the processing behavior and strength of these materials.
Collapse
|
5
|
Thermal and Morphological Properties of Poly(L-Lactic Acid)/Poly(D-Lactic Acid)-B-Polycaprolactone Diblock Copolymer Blends. MATERIALS 2020; 13:ma13112550. [PMID: 32503268 PMCID: PMC7321447 DOI: 10.3390/ma13112550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/28/2020] [Accepted: 05/30/2020] [Indexed: 12/04/2022]
Abstract
Due to the brittle nature of poly(lactic acid) many attempts have been made to flexibilize this polyester for applications such as thin films and foils. However, due to complex phase behavior, many drawbacks for plasticizer and blend components are described. To overcome miscibility, post crystallization and migration issues a principle of click-chemistry was employed to change the molecular characteristics from external to internal plasticization by fixation of a plastisizing unit with help of a stereocomplex crystallization. Hydroxyl terminated polycaprolactone oligomers were used as a macroinitiator for the ring opening polymerization of d-lactide, resulting in blockcopolymers with plasticizing unit polycaprolactone and compatibilizing poly(d-lactic acid)-blocks. The generated block copolymers were blended with a poly(l-lactic acid)-matrix and formed so called stereocomplex crystals. In comparison to unbound polycaprolactone the polycaprolactone blocks show a lower migration tendency regarding a solution test in toluene. Besides that, trapping the plasticizing units via stereocomplex also improves the efficiency of the plasticizer. In comparison to polymer blends with the same amount of non-bonded polycaprolactone oligomers of the same molecular weight, block copolymers with poly(d-lactic acid) and polycaprolactone can shift the glass transition temperature to lower values. This effect can be explained by the modulated crystallization of the polycaprolactone-blocks trapped into the matrix, so that a higher effective amount can interact with the poly(l-lactic acid)-matrix.
Collapse
|
6
|
Ramachandran K, Di Luccio T, Ailianou A, Kossuth MB, Oberhauser JP, Kornfield JA. Crimping-induced structural gradients explain the lasting strength of poly l-lactide bioresorbable vascular scaffolds during hydrolysis. Proc Natl Acad Sci U S A 2018; 115:10239-10244. [PMID: 30224483 PMCID: PMC6187115 DOI: 10.1073/pnas.1807347115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Biodegradable polymers open the way to treatment of heart disease using transient implants (bioresorbable vascular scaffolds, BVSs) that overcome the most serious complication associated with permanent metal stents-late stent thrombosis. Here, we address the long-standing paradox that the clinically approved BVS maintains its radial strength even after 9 mo of hydrolysis, which induces a ∼40% decrease in the poly l-lactide molecular weight (Mn). X-ray microdiffraction evidence of nonuniform hydrolysis in the scaffold reveals that regions subjected to tensile stress during crimping develop a microstructure that provides strength and resists hydrolysis. These beneficial morphological changes occur where they are needed most-where stress is localized when a radial load is placed on the scaffold. We hypothesize that the observed decrease in Mn reflects the majority of the material, which is undeformed during crimping. Thus, the global measures of degradation may be decoupled from the localized, degradation-resistant regions that confer the ability to support the artery for the first several months after implantation.
Collapse
Affiliation(s)
- Karthik Ramachandran
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Tiziana Di Luccio
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
- Division of Sustainable Materials, ENEA Centro Ricerche Portici, I-80055 Portici, Italy
| | - Artemis Ailianou
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | | | | | - Julia A Kornfield
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125;
| |
Collapse
|
7
|
Ramachandran K, Miscioscia R, Filippo GD, Pandolfi G, Di Luccio T, Kornfield JA. Tube Expansion Deformation Enables In Situ Synchrotron X-ray Scattering Measurements during Extensional Flow-Induced Crystallization of Poly l-Lactide Near the Glass Transition. Polymers (Basel) 2018; 10:polym10030288. [PMID: 30966323 PMCID: PMC6415077 DOI: 10.3390/polym10030288] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 03/04/2018] [Accepted: 03/06/2018] [Indexed: 12/11/2022] Open
Abstract
Coronary Heart Disease (CHD) is one of the leading causes of death worldwide, claiming over seven million lives each year. Permanent metal stents, the current standard of care for CHD, inhibit arterial vasomotion and induce serious complications such as late stent thrombosis. Bioresorbable vascular scaffolds (BVSs) made from poly l-lactide (PLLA) overcome these complications by supporting the occluded artery for 3–6 months and then being completely resorbed in 2–3 years, leaving behind a healthy artery. The BVS that recently received clinical approval is, however, relatively thick (~150 µm, approximately twice as thick as metal stents ~80 µm). Thinner scaffolds would facilitate implantation and enable treatment of smaller arteries. The key to a thinner scaffold is careful control of the PLLA microstructure during processing to confer greater strength in a thinner profile. However, the rapid time scales of processing (~1 s) defy prediction due to a lack of structural information. Here, we present a custom-designed instrument that connects the strain-field imposed on PLLA during processing to in situ development of microstructure observed using synchrotron X-ray scattering. The connection between deformation, structure and strength enables processing–structure–property relationships to guide the design of thinner yet stronger BVSs.
Collapse
Affiliation(s)
- Karthik Ramachandran
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Riccardo Miscioscia
- Division of Sustainable Materials, ENEA, Centro Ricerche Portici, 80055 Portici, Italy.
| | - Giovanni De Filippo
- Division of Photovoltaics and Smart Networks, Innovative Device Unit, Centro Ricerche Portici, 80055 Portici, Italy.
| | - Giuseppe Pandolfi
- Division of Sustainable Materials, ENEA, Centro Ricerche Portici, 80055 Portici, Italy.
| | - Tiziana Di Luccio
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
- Division of Sustainable Materials, ENEA, Centro Ricerche Portici, 80055 Portici, Italy.
| | - Julia A Kornfield
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| |
Collapse
|
8
|
Li X, Zhang X, Liu G, Yang Z, Yang B, Qi Y, Wang R, Wang DY. Effect of stereocomplex crystal and flexible segments on the crystallization and tensile behavior of poly(l-lactide). RSC Adv 2018; 8:28453-28460. [PMID: 35542484 PMCID: PMC9083944 DOI: 10.1039/c8ra05355c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 07/30/2018] [Indexed: 12/12/2022] Open
Abstract
Effect of stereocomplex crystal and PEG segments in blends on the crystallization and tensile behavior of PLLA.
Collapse
Affiliation(s)
- Xiaolu Li
- Beijing Key Laboratory of Clothing Materials R & D and Assessment
- Beijing Engineering Research Center of Textile Nanofiber
- School of Materials Science & Engineering
- Beijing Institute of Fashion Technology
- Beijing 100029
| | - Xiuqin Zhang
- Beijing Key Laboratory of Clothing Materials R & D and Assessment
- Beijing Engineering Research Center of Textile Nanofiber
- School of Materials Science & Engineering
- Beijing Institute of Fashion Technology
- Beijing 100029
| | - Guoming Liu
- CAS Key Laboratory of Engineering Plastics
- CAS Research/Education Center for Excellence in Molecular Sciences
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
| | - Zhongkai Yang
- Beijing Key Laboratory of Clothing Materials R & D and Assessment
- Beijing Engineering Research Center of Textile Nanofiber
- School of Materials Science & Engineering
- Beijing Institute of Fashion Technology
- Beijing 100029
| | - Bo Yang
- Beijing Key Laboratory of Clothing Materials R & D and Assessment
- Beijing Engineering Research Center of Textile Nanofiber
- School of Materials Science & Engineering
- Beijing Institute of Fashion Technology
- Beijing 100029
| | - Yue Qi
- Beijing Key Laboratory of Clothing Materials R & D and Assessment
- Beijing Engineering Research Center of Textile Nanofiber
- School of Materials Science & Engineering
- Beijing Institute of Fashion Technology
- Beijing 100029
| | - Rui Wang
- Beijing Key Laboratory of Clothing Materials R & D and Assessment
- Beijing Engineering Research Center of Textile Nanofiber
- School of Materials Science & Engineering
- Beijing Institute of Fashion Technology
- Beijing 100029
| | | |
Collapse
|
9
|
Takhulee A, Takahashi Y, Vao-soongnern V. Molecular simulation and experimental studies of the miscibility of PLA/PLAx-PEGy-PLAx blends. JOURNAL OF POLYMER RESEARCH 2017. [DOI: 10.1007/s10965-017-1344-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
10
|
Jing Z, Shi X, Zhang G. Competitive Stereocomplexation and Homocrystallization Behaviors in the Poly(lactide) Blends of PLLA and PDLA-PEG-PDLA with Controlled Block Length. Polymers (Basel) 2017; 9:E107. [PMID: 30970786 PMCID: PMC6432197 DOI: 10.3390/polym9030107] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 03/09/2017] [Accepted: 03/12/2017] [Indexed: 11/16/2022] Open
Abstract
Stereocomplex poly(lactide) (PLA) was obtained by solution blending of linear PLLA and PDLA-PEG-PDLA. Effects of the L/D ratios, PEG block, and PDLA block on stereocomplexation of the blends are systemically discussed. The full stereocomplex PLA can be acquired by solution blending when L/D ratios are in the range of 7/3⁻5/5. The experiment results demonstrated that the stereocomplex degree of PLLA/PDLA-PEG-PDLA prepared by melt blending was closely related to the PEG block and PDLA block. POM results indicated that the blends with high L/D ratio showed large disordered spherulites, and the typical Maltese cross pattern was observed as the L/D ratios decreased. The results of PEG block on the stereocomplexation of PLLA/PDLA-PEG-PDLA revealed that the PEG blocks possessed two sides: accelerating agent for the mobility of polymer chains and decreasing nucleation capacity due to their diluting effect. The effect of PDLA block on the stereocomplexation of the blends was also well investigated. The results showed that the crystallization of sc-crystallites and hc-crystallites in the PLLA/PDLA-PEG4k-PDLA blends with different PDLA blocks presents an obvious competition relationship, and this is not beneficial to the formation of sc-crystallites with increasing PDLA block. The melting behavior of PLLA/PDLA-PEG4k-PDLA with different PDLA blocks after isothermal crystallization showed that the blends could achieve full stereocomplex when the crystallization temperature exceeded 160 °C, and a crystallite with high perfection could be formed as the crystallization temperature increased. This study systemically investigated the effects of the L/D ratios, PEG block, PDLA block, and crystallization conditions on stereocomplex crystallization of PLLA/PDLA-PEG-PDLA blends, which can provide potential approaches to control the microstructure and physical performances of PLLA/PDLA-PEG-PDLA blends.
Collapse
Affiliation(s)
- Zhanxin Jing
- Ministry of Education Key Lab of Applied Physics and Chemistry in Space, College of Science, Northwestern Polytechnical University, Xi'an 710072, China.
| | - Xuetao Shi
- Ministry of Education Key Lab of Applied Physics and Chemistry in Space, College of Science, Northwestern Polytechnical University, Xi'an 710072, China.
| | - Guangcheng Zhang
- Ministry of Education Key Lab of Applied Physics and Chemistry in Space, College of Science, Northwestern Polytechnical University, Xi'an 710072, China.
| |
Collapse
|
11
|
Huang T, Yamaguchi M. Effect of cooling conditions on the mechanical properties of crystalline poly(lactic acid). J Appl Polym Sci 2017. [DOI: 10.1002/app.44960] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Tong Huang
- School of Materials Science; Japan Advanced Institute of Science and Technology; 1-1 Asahidai Nomi Ishikawa 923-1292 Japan
| | - Masayuki Yamaguchi
- School of Materials Science; Japan Advanced Institute of Science and Technology; 1-1 Asahidai Nomi Ishikawa 923-1292 Japan
| |
Collapse
|
12
|
Affiliation(s)
- Ming Wang
- School of Chemistry and Chemical Engineering, Southwest University, Chongqing, P. R. China
| | - Ying Wu
- School of Chemistry and Chemical Engineering, Southwest University, Chongqing, P. R. China
| | - Yi-Dong Li
- School of Chemistry and Chemical Engineering, Southwest University, Chongqing, P. R. China
| | - Jian-Bing Zeng
- School of Chemistry and Chemical Engineering, Southwest University, Chongqing, P. R. China
| |
Collapse
|
13
|
Abstract
Upon blending enantiomeric poly(l-lactide) [i.e., poly(l-lactic acid) (PLLA)] and poly(d-lactide) (PDLA) [i.e., poly(d-lactic acid) (PDLA)] or synthesis of stereo block poly(lactide) [i.e., poly(lactic acid) (PLA)], a stereocomplex (SC) is formed. PLA SC has a higher melting temperature (or heat resistance), mechanical performance, and hydrolysis-resistance compared to those of neat PLLA and PDLA. Because of such effects, PLA SC has been extensively studied in terms of biomedical and pharmaceutical applications as well as commodity, industrial, and environmental applications. Stereocomplexation stabilizes and strengthens PLA-based hydrogel or nanoparticles for biomedical applications. Stereocomplexation increases the barrier property of PLA-based materials and thereby prolongs drug release from PLA based materials. In addition, PLA SC is attracting significant attention because it can act as a nucleating agent for the widely used biobased polymer PLLA and thereby the heat resistance of PLLA-based materials can be enhanced. Interestingly, a wide variety of SCs other than PLA SC are found to have been formed in the enantiomeric substituted PLA blends and stereo block substituted PLA polymers. In the present review article, a decade of progress in investigation of PLA SCs is summarized.
Collapse
Affiliation(s)
- Hideto Tsuji
- Department of Environmental and Life Sciences, Graduate School of Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441-8580, Japan.
| |
Collapse
|
14
|
Multiplicity of morphologies in poly (l-lactide) bioresorbable vascular scaffolds. Proc Natl Acad Sci U S A 2016; 113:11670-11675. [PMID: 27671659 DOI: 10.1073/pnas.1602311113] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Poly(l-lactide) (PLLA) is the structural material of the first clinically approved bioresorbable vascular scaffold (BVS), a promising alternative to permanent metal stents for treatment of coronary heart disease. BVSs are transient implants that support the occluded artery for 6 mo and are completely resorbed in 2 y. Clinical trials of BVSs report restoration of arterial vasomotion and elimination of serious complications such as late stent thrombosis. It is remarkable that a scaffold made from PLLA, known as a brittle polymer, does not fracture when crimped onto a balloon catheter or during deployment in the artery. We used X-ray microdiffraction to discover how PLLA acquired ductile character and found that the crimping process creates localized regions of extreme anisotropy; PLLA chains in the scaffold change orientation from the hoop direction to the radial direction on micrometer-scale distances. This multiplicity of morphologies in the crimped scaffold works in tandem to enable a low-stress response during deployment, which avoids fracture of the PLLA hoops and leaves them with the strength needed to support the artery. Thus, the transformations of the semicrystalline PLLA microstructure during crimping explain the unexpected strength and ductility of the current BVS and point the way to thinner resorbable scaffolds in the future.
Collapse
|
15
|
de Araújo JP, Silva RC, Lima JCC, Agrawal P, de Mélo TJA. Mechanical and Thermal Behavior of PLA/PEgAA Blends. ACTA ACUST UNITED AC 2016. [DOI: 10.1002/masy.201500140] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jeane P. de Araújo
- Department of Materials Engineering; Federal University of Campina Grande; Av. Aprígio Veloso, 882, Universitário 58429-900 Campina Grande − PB Brazil
| | - Reinaldo C. Silva
- Department of Materials Engineering; Federal University of Campina Grande; Av. Aprígio Veloso, 882, Universitário 58429-900 Campina Grande − PB Brazil
| | - Jéssica C. C. Lima
- Department of Materials Engineering; Federal University of Campina Grande; Av. Aprígio Veloso, 882, Universitário 58429-900 Campina Grande − PB Brazil
| | - Pankaj Agrawal
- Department of Materials Engineering; Federal University of Campina Grande; Av. Aprígio Veloso, 882, Universitário 58429-900 Campina Grande − PB Brazil
| | - Tomás J. A. de Mélo
- Department of Materials Engineering; Federal University of Campina Grande; Av. Aprígio Veloso, 882, Universitário 58429-900 Campina Grande − PB Brazil
| |
Collapse
|
16
|
|
17
|
Karami S, Lafleur PG. Toughening of polylactide nanocomposites with an ethylene alkyl acrylate copolymer: Effects of the addition of nanoparticles on phase morphology and fracture mechanisms. POLYM ENG SCI 2016. [DOI: 10.1002/pen.24377] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Shahir Karami
- Chemical Engineering Department; CREPEC, École Polytechnique de Montréal; C.P. 6079, Succ. Centre ville Montréal Québec Canada H3C 3A7
| | - Pierre G. Lafleur
- Chemical Engineering Department; CREPEC, École Polytechnique de Montréal; C.P. 6079, Succ. Centre ville Montréal Québec Canada H3C 3A7
| |
Collapse
|
18
|
Hu J, Tashiro K. Time-Resolved Imaging of the Phase Transition in the Melt-Grown Spherulites of Isotactic Polybutene-1 as Detected by the Two-Dimensional Polarized IR Imaging Technique. J Phys Chem B 2016; 120:4689-98. [PMID: 27149425 DOI: 10.1021/acs.jpcb.6b01229] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In order to visualize the 2D spatial distribution of the structural change in the phase transition from crystal form II to I of isotactic polybutene-1 spherulite grown from the melt, the time-dependent measurement of the 2D polarized FTIR spectra has been performed. At a melt-isothermal crystallization temperature of 103 °C, the square-shape spherulite appeared from the melt and grew with time. When the isothermal crystallization occurred at 98 °C, the round-shaped spherulite was observed. In both cases, after the temperature jump to an ambient temperature, the 2D images changed clearly in the process of the phase transition from form II to form I, but the spherulite morphology itself was not changed detectably. The polarized IR imaging has revealed the preferential orientation of the crystallites in the spherulite. In the case of the spherulite grown at 103 °C, the ab plane is oriented in parallel to the spherulite plane and the molecular chains stand along the normal to the surface. On the other hand, in the spherulite grown at 98 °C, the chains were found to lie on the spherulite plane preferentially. Such a difference in the crystal orientation in the spherulite is related intimately with the outer shape of the spherulite and also with the growth mechanism of the spherulite. In this way, the polarized 2D IR imaging was found to be quite useful for the in situ detection of the time-dependently changing 2D spatial distribution of the crystallites in the spherulite.
Collapse
Affiliation(s)
- Jian Hu
- Department of Future Industry-Oriented Basic Science and Materials, Toyota Technological Institute , Tempaku, Nagoya 468-8511, Japan
| | - Kohji Tashiro
- Department of Future Industry-Oriented Basic Science and Materials, Toyota Technological Institute , Tempaku, Nagoya 468-8511, Japan
| |
Collapse
|
19
|
Tsuji H. WITHDRAWN: PLA Stereocomplexes: A Decade of Progress. Adv Drug Deliv Rev 2016:S0169-409X(16)30009-6. [PMID: 26785171 DOI: 10.1016/j.addr.2015.12.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 12/31/2015] [Indexed: 12/16/2022]
Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
Collapse
Affiliation(s)
- Hideto Tsuji
- Department of Environmental and Life Sciences, Graduate School of Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441-8580, Japan.
| |
Collapse
|
20
|
Arrieta M, López J, López D, Kenny J, Peponi L. Development of flexible materials based on plasticized electrospun PLA–PHB blends: Structural, thermal, mechanical and disintegration properties. Eur Polym J 2015. [DOI: 10.1016/j.eurpolymj.2015.10.036] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
21
|
Tacha S, Saelee T, Khotasen W, Punyodom W, Molloy R, Worajittiphon P, Meepowpan P, Manokruang K. Stereocomplexation of PLL/PDL–PEG–PDL blends: Effects of blend morphology on film toughness. Eur Polym J 2015. [DOI: 10.1016/j.eurpolymj.2015.06.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
22
|
Cheng HY, Yang YJ, Li SC, Hong JY, Jang GW. Modification and extrusion coating of polylactic acid films. J Appl Polym Sci 2015. [DOI: 10.1002/app.42472] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Hsiu-Yu Cheng
- Chemical Engineering Division; Material and Chemical Laboratories, Industrial Technology Research Institute; 321 Kuang Fu Road sec. 2 Hsinchu 30011 Taiwan Republic of China
| | - Yin-Ju Yang
- Chemical Engineering Division; Material and Chemical Laboratories, Industrial Technology Research Institute; 321 Kuang Fu Road sec. 2 Hsinchu 30011 Taiwan Republic of China
| | - Shu-Chen Li
- Chemical Engineering Division; Material and Chemical Laboratories, Industrial Technology Research Institute; 321 Kuang Fu Road sec. 2 Hsinchu 30011 Taiwan Republic of China
| | - Jian-Yi Hong
- Chemical Engineering Division; Material and Chemical Laboratories, Industrial Technology Research Institute; 321 Kuang Fu Road sec. 2 Hsinchu 30011 Taiwan Republic of China
| | - Guang-Way Jang
- Chemical Engineering Division; Material and Chemical Laboratories, Industrial Technology Research Institute; 321 Kuang Fu Road sec. 2 Hsinchu 30011 Taiwan Republic of China
| |
Collapse
|
23
|
Xie X, Bai W, Wu A, Chen D, Xiong C, Tang C, Pang X. Increasing the compatibility of poly( l-lactide)/poly( para-dioxanone) blends through the addition of poly( para-dioxanone- co- l-lactide). J Appl Polym Sci 2015. [DOI: 10.1002/app.41323] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Xulong Xie
- Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; Chengdu 610041 People's Republic of China
- University of Chinese Academy of Sciences; Beijing 100039 People's Republic of China
| | - Wei Bai
- Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; Chengdu 610041 People's Republic of China
| | - Ai Wu
- Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; Chengdu 610041 People's Republic of China
- University of Chinese Academy of Sciences; Beijing 100039 People's Republic of China
| | - Dongliang Chen
- Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; Chengdu 610041 People's Republic of China
| | - Chengdong Xiong
- Chengdu Institute of Organic Chemistry; Chinese Academy of Sciences; Chengdu 610041 People's Republic of China
| | - Congming Tang
- Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering; China West Normal University; Nanchong 637009 People's Republic of China
| | - Xiubing Pang
- Zhejiang Engineering Research Center in Biodegradable Medical Materials; Dongyang 322100 People's Republic of China
| |
Collapse
|
24
|
Bao RY, Yang W, Liu ZY, Xie BH, Yang MB. Polymorphism of a high-molecular-weight racemic poly(l-lactide)/poly(d-lactide) blend: effect of melt blending with poly(methyl methacrylate). RSC Adv 2015. [DOI: 10.1039/c5ra00691k] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The polymorphic crystallization of a high-molecular-weight PLLA/PDLA blend can be tailored by the amount of PMMA and dynamic and isothermal crystallization conditions.
Collapse
Affiliation(s)
- Rui-Ying Bao
- College of Polymer Science and Engineering
- Sichuan University
- State Key Laboratory of Polymer Materials Engineering
- Chengdu
- China
| | - Wei Yang
- College of Polymer Science and Engineering
- Sichuan University
- State Key Laboratory of Polymer Materials Engineering
- Chengdu
- China
| | - Zheng-Ying Liu
- College of Polymer Science and Engineering
- Sichuan University
- State Key Laboratory of Polymer Materials Engineering
- Chengdu
- China
| | - Bang-Hu Xie
- College of Polymer Science and Engineering
- Sichuan University
- State Key Laboratory of Polymer Materials Engineering
- Chengdu
- China
| | - Ming-Bo Yang
- College of Polymer Science and Engineering
- Sichuan University
- State Key Laboratory of Polymer Materials Engineering
- Chengdu
- China
| |
Collapse
|
25
|
Ning Z, Jiang N, Gan Z. Four-armed PCL-b-PDLA diblock copolymer: 1. Synthesis, crystallization and degradation. Polym Degrad Stab 2014. [DOI: 10.1016/j.polymdegradstab.2014.05.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
26
|
Chen BY, Wang YS, Mi HY, Yu P, Kuang TR, Peng XF, Wen JS. Effect of poly(ethylene glycol) on the properties and foaming behavior of macroporous poly(lactic acid)/sodium chloride scaffold. J Appl Polym Sci 2014. [DOI: 10.1002/app.41181] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Bin-Yi Chen
- School of Mechanical and Automotive Engineering, National Engineering Research Center of Novel Equipment for Polymer Processing; Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology; Guangzhou 510640 China
| | - Yuan-Sheng Wang
- School of Mechanical and Automotive Engineering, National Engineering Research Center of Novel Equipment for Polymer Processing; Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology; Guangzhou 510640 China
| | - Hao-Yang Mi
- School of Mechanical and Automotive Engineering, National Engineering Research Center of Novel Equipment for Polymer Processing; Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology; Guangzhou 510640 China
| | - Peng Yu
- School of Mechanical and Automotive Engineering, National Engineering Research Center of Novel Equipment for Polymer Processing; Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology; Guangzhou 510640 China
| | - Tai-Rong Kuang
- School of Mechanical and Automotive Engineering, National Engineering Research Center of Novel Equipment for Polymer Processing; Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology; Guangzhou 510640 China
| | - Xiang-Fang Peng
- School of Mechanical and Automotive Engineering, National Engineering Research Center of Novel Equipment for Polymer Processing; Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology; Guangzhou 510640 China
| | - Jing-Song Wen
- School of Mechanical and Automotive Engineering, National Engineering Research Center of Novel Equipment for Polymer Processing; Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology; Guangzhou 510640 China
| |
Collapse
|
27
|
Maintaining Structural Stability of Poly(lactic acid): Effects of Multifunctional Epoxy based Reactive Oligomers. Polymers (Basel) 2014. [DOI: 10.3390/polym6041232] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
28
|
Serra T, Ortiz-Hernandez M, Engel E, Planell JA, Navarro M. Relevance of PEG in PLA-based blends for tissue engineering 3D-printed scaffolds. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 38:55-62. [PMID: 24656352 DOI: 10.1016/j.msec.2014.01.003] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/15/2013] [Accepted: 01/05/2014] [Indexed: 11/20/2022]
Abstract
Achieving high quality 3D-printed structures requires establishing the right printing conditions. Finding processing conditions that satisfy both the fabrication process and the final required scaffold properties is crucial. This work stresses the importance of studying the outcome of the plasticizing effect of PEG on PLA-based blends used for the fabrication of 3D-direct-printed scaffolds for tissue engineering applications. For this, PLA/PEG blends with 5, 10 and 20% (w/w) of PEG and PLA/PEG/bioactive CaP glass composites were processed in the form of 3D rapid prototyping scaffolds. Surface analysis and differential scanning calorimetry revealed a rearrangement of polymer chains and a topography, wettability and elastic modulus increase of the studied surfaces as PEG was incorporated. Moreover, addition of 10 and 20% PEG led to non-uniform 3D structures with lower mechanical properties. In vitro degradation studies showed that the inclusion of PEG significantly accelerated the degradation rate of the material. Results indicated that the presence of PEG not only improves PLA processing but also leads to relevant surface, geometrical and structural changes including modulation of the degradation rate of PLA-based 3D printed scaffolds.
Collapse
Affiliation(s)
- Tiziano Serra
- Institute for Bioengineering of Catalonia (IBEC), Biomaterials for Regenerative Therapies, Baldiri Reixac 15-21, 08028 Barcelona, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain
| | - Monica Ortiz-Hernandez
- Institute for Bioengineering of Catalonia (IBEC), Biomaterials for Regenerative Therapies, Baldiri Reixac 15-21, 08028 Barcelona, Spain
| | - Elisabeth Engel
- Institute for Bioengineering of Catalonia (IBEC), Biomaterials for Regenerative Therapies, Baldiri Reixac 15-21, 08028 Barcelona, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain; Technical University of Catalonia (UPC), Barcelona, Spain
| | - Josep A Planell
- Institute for Bioengineering of Catalonia (IBEC), Biomaterials for Regenerative Therapies, Baldiri Reixac 15-21, 08028 Barcelona, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain; Technical University of Catalonia (UPC), Barcelona, Spain
| | - Melba Navarro
- Institute for Bioengineering of Catalonia (IBEC), Biomaterials for Regenerative Therapies, Baldiri Reixac 15-21, 08028 Barcelona, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain.
| |
Collapse
|
29
|
|
30
|
Rasselet D, Ruellan A, Guinault A, Miquelard-Garnier G, Sollogoub C, Fayolle B. Oxidative degradation of polylactide (PLA) and its effects on physical and mechanical properties. Eur Polym J 2014. [DOI: 10.1016/j.eurpolymj.2013.10.011] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
31
|
Rathi SR, Ng D, Coughlin EB, Hsu SL, Golub CS, Ling GH, Tzivanis MJ. Effects of Molecular Architecture on the Stereocomplex Crystallization in Poly(lactic acid) Blends. MACROMOL CHEM PHYS 2013. [DOI: 10.1002/macp.201300589] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sahas R. Rathi
- Polymer Science and Engineering; University of Massachusetts; Amherst MA 01003 USA
| | - David Ng
- Polymer Science and Engineering; University of Massachusetts; Amherst MA 01003 USA
| | - E. Bryan Coughlin
- Polymer Science and Engineering; University of Massachusetts; Amherst MA 01003 USA
| | - Shaw Ling Hsu
- Polymer Science and Engineering; University of Massachusetts; Amherst MA 01003 USA
| | - Charles S. Golub
- Saint Gobain Northborough Research & Development Center; 9 Goddard Road Northborough MA 01532 USA
| | - Gerald H. Ling
- Saint Gobain Northborough Research & Development Center; 9 Goddard Road Northborough MA 01532 USA
| | - Michael J. Tzivanis
- Saint Gobain Northborough Research & Development Center; 9 Goddard Road Northborough MA 01532 USA
| |
Collapse
|
32
|
Kutikov AB, Song J. An amphiphilic degradable polymer/hydroxyapatite composite with enhanced handling characteristics promotes osteogenic gene expression in bone marrow stromal cells. Acta Biomater 2013; 9:8354-64. [PMID: 23791675 PMCID: PMC3745304 DOI: 10.1016/j.actbio.2013.06.013] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 05/31/2013] [Accepted: 06/10/2013] [Indexed: 01/13/2023]
Abstract
Electrospun polymer/hydroxyapatite (HA) composites combining biodegradability with osteoconductivity are attractive for skeletal tissue engineering applications. However, most biodegradable polymers such as poly(lactic acid) (PLA) are hydrophobic and do not blend with adequate interfacial adhesion with HA, compromising the structural homogeneity, mechanical integrity and biological performance of the composite. To overcome this challenge, we combined a hydrophilic polyethylene glycol (PEG) block with poly(d,l-lactic acid) to improve the adhesion of the degradable polymer with HA. The amphiphilic triblock copolymer PLA-PEG-PLA (PELA) improved the stability of HA-PELA suspension at 25wt.% HA content, which was readily electrospun into HA-PELA composite scaffolds with uniform fiber dimensions. HA-PELA was highly extensible (failure strain>200% vs. <40% for HA-PLA), superhydrophilic (∼0° water contact angle vs. >100° for HA-PLA), and exhibited an 8-fold storage modulus increase (unlike deterioration for HA-PLA) upon hydration, owing to the favorable interaction between HA and PEG. HA-PELA also better promoted osteochondral lineage commitment of bone marrow stromal cells in unstimulated culture and supported far more potent osteogenic gene expression upon induction than HA-PLA. We demonstrate that the chemical incorporation of PEG is an effective strategy to improve the performance of degradable polymer/HA composites for bone tissue engineering applications.
Collapse
Affiliation(s)
- Artem B. Kutikov
- Department of Orthopedics & Physical Rehabilitation, Department of Cell and Developmental Biology. University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655, USA
| | - Jie Song
- Department of Orthopedics & Physical Rehabilitation, Department of Cell and Developmental Biology. University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655, USA
| |
Collapse
|
33
|
Bai H, Huang C, Xiu H, Gao Y, Zhang Q, Fu Q. Toughening of poly(l-lactide) with poly(ε-caprolactone): Combined effects of matrix crystallization and impact modifier particle size. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.07.051] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
34
|
Insight into the annealing peak and microstructural changes of poly(l-lactic acid) by annealing at elevated temperatures. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.04.027] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
35
|
|
36
|
Bao RY, Yang W, Jiang WR, Liu ZY, Xie BH, Yang MB. Polymorphism of Racemic Poly(l-lactide)/Poly(d-lactide) Blend: Effect of Melt and Cold Crystallization. J Phys Chem B 2013; 117:3667-74. [DOI: 10.1021/jp311878f] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Rui-Ying Bao
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer
Materials Engineering, Chengdu, 610065, Sichuan, China
| | - Wei Yang
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer
Materials Engineering, Chengdu, 610065, Sichuan, China
| | - Wen-Rou Jiang
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer
Materials Engineering, Chengdu, 610065, Sichuan, China
| | - Zheng-Ying Liu
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer
Materials Engineering, Chengdu, 610065, Sichuan, China
| | - Bang-Hu Xie
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer
Materials Engineering, Chengdu, 610065, Sichuan, China
| | - Ming-Bo Yang
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer
Materials Engineering, Chengdu, 610065, Sichuan, China
| |
Collapse
|
37
|
Rahaman MH, Tsuji H. Isothermal crystallization and spherulite growth behavior of stereo multiblock poly(lactic acid)s: Effects of block length. J Appl Polym Sci 2013. [DOI: 10.1002/app.38953] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
38
|
Xu H, Zhong GJ, Fu Q, Lei J, Jiang W, Hsiao BS, Li ZM. Formation of shish-kebabs in injection-molded poly(L-lactic acid) by application of an intense flow field. ACS APPLIED MATERIALS & INTERFACES 2012; 4:6774-6784. [PMID: 23153180 DOI: 10.1021/am3019756] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Unlike polyolefins (e.g., isotactic polypropylene), it is still a great challenge to form rich shish-kebabs in biodegradable poly(L-lactic acid) (PLLA) because of its short chain length and semirigid chain backbone. In the present work, a modified injection molding technology, named oscillation shear injection molding, was applied to provide an intense shear flow on PLLA melt in mold cavity, in order to promote shear-induced crystallization of PLLA. Additionally, a small amount of poly(ethylene glycol) (PEG) with flexible chains was introduced for improving the crystallization kinetics. Numerous shish-kebabs of PLLA were achieved in injection-molded PLLA for the first time. High-resolution scanning electronic microscopy and small-angle X-ray scattering showed a structure feature of shish-kebabs with a diameter of around 0.7 μm and a long period of ~20 nm. The wide-angle X-ray diffraction results showed that shish-kebabs had more ordered crystalline structure of α-form. A significant improvement of the mechanical properties was obtained; the tensile strength and modulus increased to 73.7 and 1888 MPa from the initial values of 64.9 and 1684 MPa, respectively, meanwhile the ductility is not deteriorated. Interestingly, when shish-kebabs form in the PLLA/PEG system, a bamboo-like bionic structure comprising a hard skin layer and a soft core develops in injection-molded specimen. This unique structure leads to a great balance of mechanical properties, including substantial increments of 26, 20, and 112% in the tensile strength, modulus, and impact toughness, compared to the control sample. Further exploration will give a rich fundamental understanding in the shear-induced crystallization and morphology manipulation of PLLA, aiming to achieve superior PLLA products.
Collapse
Affiliation(s)
- Huan Xu
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, Sichuan, People's Republic of China
| | | | | | | | | | | | | |
Collapse
|
39
|
|
40
|
Ye S, Ting Lin T, Weei Tjiu W, Kwan Wong P, He C. Rubber toughening of poly(lactic acid): Effect of stereocomplex formation at the rubber-matrix interface. J Appl Polym Sci 2012. [DOI: 10.1002/app.38568] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
41
|
Xu Y, Sun Z, Chen X, Chen M, Hu S, Zhang Z. Mechanical Properties and Crystallization Behavior of Polycarbonate/Polypropylene Blends. J MACROMOL SCI B 2012. [DOI: 10.1080/00222348.2012.721659] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Yang Xu
- a Key Laboratory of Advanced Materials Technology Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu , China
| | - Zhidan Sun
- b School of Life Science and Engineering, Southwest Jiaotong University , Chengdu , China
| | - Xiaolang Chen
- a Key Laboratory of Advanced Materials Technology Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu , China
| | - Man Chen
- a Key Laboratory of Advanced Materials Technology Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu , China
| | - Shuchun Hu
- a Key Laboratory of Advanced Materials Technology Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu , China
| | - Zhibin Zhang
- b School of Life Science and Engineering, Southwest Jiaotong University , Chengdu , China
| |
Collapse
|
42
|
Shao J, Sun J, Bian X, Cui Y, Li G, Chen X. Investigation of Poly(lactide) Stereocomplexes: 3-Armed Poly(l-lactide) Blended with Linear and 3-Armed Enantiomers. J Phys Chem B 2012; 116:9983-91. [DOI: 10.1021/jp303402j] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jun Shao
- Key Laboratory of Polymer Ecomaterials,
Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
- Graduate University of the Chinese Academy of Sciences, Beijing 100039,
China
| | - Jingru Sun
- Key Laboratory of Polymer Ecomaterials,
Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Xinchao Bian
- Key Laboratory of Polymer Ecomaterials,
Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Yi Cui
- Key Laboratory of Polymer Ecomaterials,
Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Gao Li
- Key Laboratory of Polymer Ecomaterials,
Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Xuesi Chen
- Key Laboratory of Polymer Ecomaterials,
Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| |
Collapse
|
43
|
Gao M, Ren Z, Yan S, Sun J, Chen X. An optical microscopy study on the phase structure of poly(L-lactide acid)/poly(propylene carbonate) blends. J Phys Chem B 2012; 116:9832-7. [PMID: 22827324 DOI: 10.1021/jp3041378] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dependence of phase structure of PLLA/PPC blends on the blend ratio, the heat-treatment temperature and time was investigated by optical microscopy. It is found that, at lower PPC content, e.g., less than 30%, the PLLA crystalline spherulites fill the whole space with the PPC dispersed in the amorphous region of PLLA. No evident phase separation has been observed under optical microscope. When the content of PPC reaches 40%, phase separation takes place. The phase separation of the PLLA/PPC blend happens prior to the crystallization of PLLA. Therefore, the heat-treatment temperature and time are the two most important factors that control the phase structure of the blend. At low heat-treatment temperatures, e.g., lower than 190 °C, the PPC and the amorphous PLLA part compose a continuous phase with the crystalline PLLA domains dispersed in it. When the sample was heat-treated at 200 °C for 5 min, a bicontinuous phase structure was observed. With further increase of the heat-treatment temperature, the crystalline PLLA composes the continuous phase with PPC domains randomly dispersed in it. Similar phase reversal phenomenon has also been observed by heat-treating the samples at 200 °C for different times. It is further confirmed that the crystallization of PLLA in the blends is influenced by the different phase structures. For example, the crystallinity of PLLA in the blend increases with increasing heat-treatment temperature.
Collapse
Affiliation(s)
- Min Gao
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | | | | | | | | |
Collapse
|
44
|
Rathi SR, Coughlin EB, Hsu SL, Golub CS, Ling GH, Tzivanis MJ. Effect of midblock on the morphology and properties of blends of ABA triblock copolymers of PDLA-mid-block-PDLA with PLLA. POLYMER 2012. [DOI: 10.1016/j.polymer.2012.05.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
45
|
Bai H, Xiu H, Gao J, Deng H, Zhang Q, Yang M, Fu Q. Tailoring impact toughness of poly(L-lactide)/poly(ε-caprolactone) (PLLA/PCL) blends by controlling crystallization of PLLA matrix. ACS APPLIED MATERIALS & INTERFACES 2012; 4:897-905. [PMID: 22214560 DOI: 10.1021/am201564f] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Melt blending poly(L-lactide) (PLLA) with various biodegradable polymers has been thought to be the most economic and effective route to toughen PLLA without compromising its biodegradability. Unfortunately, only very limited improvement in notched impact toughness can be achieved, although most of these blends show significant enhancement in tensile toughness. In this work, biodegradable poly(ε-caprolactone) (PCL) was used as an impact modifier to toughen PLLA and a nucleating agent was utilized to tailor the crystallization of PLLA matrix. Depending on the nucleating agent concentrations in the matrix and mold temperatures in injection molding, PLLA/PCL blends with a wide range of matrix crystallinity (10-50%) were prepared by practical injection molding. The results show that there is a linear relationship between PLLA matrix crystallinity and impact toughness. With the increase in PLLA crystalline content, toughening becomes much easier to achieve. PLLA crystals are believed to provide a path for the propagation of shear yielding needed for effective impact energy absorption, and then, excellent toughening effect can be obtained when these crystals percolate through the whole matrix. This investigation provides not only a new route to prepare sustainable PLLA products with good impact toughness but also a fresh insight into the importance of matrix crystallization in the toughening of semicrystalline polymers with a flexible polymer.
Collapse
Affiliation(s)
- Hongwei Bai
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, PR China
| | | | | | | | | | | | | |
Collapse
|