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Li W, Cao J, Fu L, Liu F, Huang Y, He Y, Jiang L, Dan Y. Effect of stereo-complexation on crystallization behavior and barrier properties of poly-lactide. Int J Biol Macromol 2024; 261:129834. [PMID: 38302029 DOI: 10.1016/j.ijbiomac.2024.129834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 01/26/2024] [Accepted: 01/27/2024] [Indexed: 02/03/2024]
Abstract
The unique stere-complex crystal formed by poly(ʟ-lactide)/poly(ᴅ-lactide) (PLLA/PDLA) has a significant impact on properties of poly-lactide materials and is considered an effective means to improve the barrier properties of poly-lactide (PLA). In this work, poly-lactide films with different aggregate structures were prepared and the relationship of aggregate structure and barrier properties were explored. The results show that the crystal structure including crystallinity and crystal forms can be controlled by adjusting the isothermal crystallization time and crystallization temperature during the molding process. PLLA/PDLA composite films contain both homochiral crystallites and stereo-complex crystallites, and there is a synergistic crystallization effect between the two of them, which provides the composite films with high crystallinity and excellent barrier properties. Compared to the PLLA with homochiral crystallites, the PLLA/PDLA composite film with only stereo-complex crystallites exhibits higher barrier properties. The linear correlation between the crystallinity and the barrier properties is weak due to the changes in crystallization behavior and then the structure of poly-lactide caused by stereo-complexation. The linear correlation between the crystallinity and the barrier properties of the blend film is strong in the low crystallinity but weak at high crystallinity. Compared to homochiral crystallites, stereo-complex crystallites exhibits lower crystallinity dependence. It has been proven that different crystal forms have different design ideas for preparing high-barrier films, but the stereo-complexation resulting from the intermolecular forces between PLLA and PDLA having complementary chemical structure, is an effective method for enhancing the barrier performances of poly-lactide sustainably.
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Affiliation(s)
- Wanling Li
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute of Sichuan University, Chengdu 610065, China
| | - Jilong Cao
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute of Sichuan University, Chengdu 610065, China
| | - Ling Fu
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute of Sichuan University, Chengdu 610065, China
| | - Fei Liu
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute of Sichuan University, Chengdu 610065, China
| | - Yun Huang
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute of Sichuan University, Chengdu 610065, China
| | - Yuan He
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute of Sichuan University, Chengdu 610065, China
| | - Long Jiang
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute of Sichuan University, Chengdu 610065, China.
| | - Yi Dan
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute of Sichuan University, Chengdu 610065, China.
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Vosough Kia M, Ehsani M, Hosseini SE, Asadi GH. Fabrication and characterization of transparent nanocomposite films based on poly (lactic acid)/polyethylene glycol reinforced with nano glass flake. Int J Biol Macromol 2024; 254:127473. [PMID: 37858646 DOI: 10.1016/j.ijbiomac.2023.127473] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 10/13/2023] [Accepted: 10/14/2023] [Indexed: 10/21/2023]
Abstract
Developing new biodegradable packaging with superior properties and advanced functionalities is one of the most emerging research areas of interest in food packaging. In this study, PLA/PEG-based nanocomposite films incorporated with different amounts of nano glass flake (NGF) (0, 0.5, 1, and 2 phr) were fabricated via casting solution for applications in food packaging. The ATR-FTIR displayed no chemical interaction between the PLA/PEG-based matrix and NGF particles. The scanning electron microscopy (SEM) observations exhibited a relatively smooth and homogeneous surface without defects. Incorporation of the NGF into the PLA/PEG-based matrix did not affect the color and opacity of the fabricated films. The prepared nanocomposite films were highly transparent and exhibited superior properties such as increased hydrophobicity, appreciable oxygen barrier properties, and enhanced thermal stability. Dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC) analysis confirmed the existence of a single glass-transition temperature (Tg) as evidence of miscibility. According to the research results, the PLA/PEG/NGF1 nanocomposite film significantly offered the best overall performance. This work has developed new insight into the potential application of nano glass flakes in food packaging.
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Affiliation(s)
- Mahboubeh Vosough Kia
- Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Morteza Ehsani
- Department of Polymer and Textile, South Tehran Branch, Islamic Azad University, Tehran, Iran; Department of Plastics, Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran.
| | - Seyed Ebrahim Hosseini
- Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Gholam Hassan Asadi
- Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran, Iran
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Chen Q, Auras R, Kirkensgaard JJK, Uysal-Unalan I. Modulating Barrier Properties of Stereocomplex Polylactide: The Polymorphism Mechanism and Its Relationship with Rigid Amorphous Fraction. ACS APPLIED MATERIALS & INTERFACES 2023; 15:49678-49688. [PMID: 37832031 DOI: 10.1021/acsami.3c12602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2023]
Abstract
The barrier properties of semicrystalline polymers are crucial for their performance and their use as packaging materials. This work uncovers the mechanism of polymorphism modification (α, α' and stereocomplex-crystals) and its combined effect on the oxygen and water vapor barrier properties of semicrystalline stereocomplex polylactide (SCPLA). A polymorphic selective filler-type nucleator was employed to eliminate the temperature effect on the development of polymorphism and rigid amorphous fraction (RAF), allowing correlations of barrier properties with different crystal forms and RAF combinations under the same amorphous composition (SCPLA). The oxygen and water vapor barrier performances strongly correlated with crystallinity and crystal form but were not monotonically related to the RAF quantity. The study proposes that the chain conformation of intermediate phases between the crystalline and amorphous phases differs with the associated crystal forms, thereby leading to different RAF "qualities" and contributing to different gas diffusion and solubility coefficients of the amorphous regions. RAF's per unit excess free volume may be varied with crystal forms, for instance: α' ≫ SC > α. Therefore, SCPLA with α' crystals exhibited high oxygen and water vapor permeabilities. Those with high SC and α crystals showed similar barrier behaviors governed by Henry's law dissolution and followed a linear "two-phase" relationship with total crystallinity.
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Affiliation(s)
- Qi Chen
- Department of Food Science, Aarhus University, Agro Food Park 48, 8200 Aarhus N, Denmark
- CiFOOD - Center for Innovative Food Research, Aarhus University, Agro Food Park, 48, 8200 Aarhus N, Denmark
| | - Rafael Auras
- School of Packaging, Michigan State University, East Lansing, Michigan 48824-1223, United States
| | - Jacob Judas Kain Kirkensgaard
- Department of Food Science, University of Copenhagen, 1958 Frederiksberg C, Denmark
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Ilke Uysal-Unalan
- Department of Food Science, Aarhus University, Agro Food Park 48, 8200 Aarhus N, Denmark
- CiFOOD - Center for Innovative Food Research, Aarhus University, Agro Food Park, 48, 8200 Aarhus N, Denmark
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Li D, Zhang S, Zhao Z, Miao Z, Zhang G, Shi X. High-Expansion Open-Cell Polylactide Foams Prepared by Microcellular Foaming Based on Stereocomplexation Mechanism with Outstanding Oil-Water Separation. Polymers (Basel) 2023; 15:polym15091984. [PMID: 37177130 PMCID: PMC10181122 DOI: 10.3390/polym15091984] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 05/15/2023] Open
Abstract
Biodegradable polylactic acid (PLA) foams with open-cell structures are good candidates for oil-water separation. However, the foaming of PLA with high-expansion and uniform cell morphology by the traditional supercritical carbon dioxide microcellular foaming method remains a big challenge due to its low melting strength. Herein, a green facile strategy for the fabrication of open-cell fully biodegradable PLA-based foams is proposed by introducing the unique stereocomplexation mechanism between PLLA and synthesized star-shaped PDLA for the first time. A series of star-shaped PDLA with eight arms (8-s-PDLA) was synthesized with different molecular weights and added into the PLLA as modifiers. PLLA/8-s-PDLA foams with open-cells structure and high expansion ratios were fabricated by microcellular foaming with green supercritical carbon dioxide. In detail, the influences of induced 8-s-PDLA on the crystallization behavior, rheological properties, cell morphology and consequential oil-water separation performance of PLA-based foam were investigated systemically. The addition of 8-s-PDLA induced the formation of SC-PLA, enhancing crystallization by acting as nucleation sites and improving the melting strength through acting as physical cross-linking points. The further microcellular foaming of PLLA/8-s-PDLA resulted in open-cell foams of high porosity and high expansion ratios. With an optimized foaming condition, the PLLA/8-s-PDLA-13K foam exhibited an average cell size of about 61.7 μm and expansion ratio of 24. Furthermore, due to the high porosity of the interconnected open cells, the high-absorption performance of the carbon tetrachloride was up to 37 g/g. This work provides a facile green fabrication strategy for the development of environmentally friendly PLA foams with stable open-cell structures and high expansion ratios for oil-water separation.
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Affiliation(s)
- Dongsheng Li
- Key Laboratory of Macromolecular Science & Technology of Shaanxi Province, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
| | - Shuai Zhang
- Key Laboratory of Macromolecular Science & Technology of Shaanxi Province, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
| | - Zezhong Zhao
- Key Laboratory of Macromolecular Science & Technology of Shaanxi Province, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
| | - Zhenyun Miao
- Key Laboratory of Macromolecular Science & Technology of Shaanxi Province, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
| | - Guangcheng Zhang
- Key Laboratory of Macromolecular Science & Technology of Shaanxi Province, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
| | - Xuetao Shi
- Key Laboratory of Macromolecular Science & Technology of Shaanxi Province, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
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Liu H, Zhao Y, Zheng Y, Chen J, Wang J, Gao G, Bai D. Toward ultra-tough and heat-resistant biodegradable polylactide/core-shell rubber blends by regulating the distribution of rubber particles with stereocomplex crystallites. Int J Biol Macromol 2023; 232:123422. [PMID: 36708887 DOI: 10.1016/j.ijbiomac.2023.123422] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/17/2023] [Accepted: 01/21/2023] [Indexed: 01/26/2023]
Abstract
Ultra-tough and heat-resistant poly(l-lactide)/core-shell rubber (PLLA/CSR) blends were fabricated by utilizing stereocomplex (SC) crystallites to effectively regulate the CSR distribution in PLLA matrix. Linear and 3-11 armed poly(d-lactide)s (PDLAs) were synthesized and then melt-mixed with PLLA/CSR blend. Interestingly, the incorporated PDLA chains could collaborate with PLLA chains to form dense SC crystallites network in PLLA/PDLA/CSR blends, thus inducing the CSR particles to transform from uniform distribution structure to network-like structure. With increasing the PDLA arm numbers, the size of CSR clusters in the network-like structure first increased and then decreased, and the continuity of the network-like structure first remained at a high level and then decreased obviously. The formation of CSR network-like structure could remarkably improve the impact strength of PLLA/PDLA/CSR blends without deteriorating their strength and modulus (compared with PLLA/CSR blend), and the CSR network-like structure with larger-sized CSR clusters and higher continuity could help obtain higher impact strength (78.3 kJ/m2). Moreover, the heat resistance of PLLA/PDLA/CSR blends could also be significantly improved (the highest Vicat softening temperature was 131 °C) by the SC crystallites network and CSR network-like structure. This work provides an effective strategy for controlling the rubber network-like morphology and thereby preparing high-performance PLLA materials.
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Affiliation(s)
- Huili Liu
- Chongqing Key Laboratory of Environmental Materials & Remediation Technologies, College of Chemistry and Environmental Engineering, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Yaling Zhao
- Chongqing Key Laboratory of Environmental Materials & Remediation Technologies, College of Chemistry and Environmental Engineering, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Yushan Zheng
- Chongqing Key Laboratory of Environmental Materials & Remediation Technologies, College of Chemistry and Environmental Engineering, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Jianyang Chen
- Chongqing Key Laboratory of Environmental Materials & Remediation Technologies, College of Chemistry and Environmental Engineering, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Jianchuan Wang
- School of Chemistry & Chemical Engineering, Chongqing University, Chongqing 400044, China
| | - Guangyong Gao
- SWS Hemodialysis Care Co., Ltd, Chongqing, Chongqing 401120, China
| | - Dongyu Bai
- Chongqing Key Laboratory of Materials Surface & Interface Science, School of Materials Science and Engineering, Chongqing University of Arts and Sciences, Chongqing 402160, China.
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