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Sarrafan S, Li G. On Lightweight Shape Memory Vitrimer Composites. ACS APPLIED POLYMER MATERIALS 2024; 6:154-169. [PMID: 38230367 PMCID: PMC10788861 DOI: 10.1021/acsapm.3c01749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 01/18/2024]
Abstract
Lightweight materials are highly desired in many engineering applications. A popular approach to obtain lightweight polymers is to prepare polymeric syntactic foams by dispersing hollow particles, such as hollow glass microbubbles (HGMs), in a polymer matrix. Integrating shape memory vitrimers (SMVs) in fabricating these syntactic foams enhances their appeal due to the multifunctionality of SMVs. The SMV-based syntactic foams have many potential applications, including actuators, insulators, and sandwich cores. However, there is a knowledge gap in understanding the effect of the HGM volume fraction on different material properties and behaviors. In this study, we prepared an SMV-based syntactic foam to investigate the influence of the HGM volume fractions on a broad set of properties. Four sample groups, containing 40, 50, 60, and 70% HGMs by volume, were tested and compared to a control pure SMV group. A series of analyses and various chemical, physical, mechanical, thermal, rheological, and functional experiments were conducted to explore the feasibility of ultralight foams. Notably, the effect of HGM volume fractions on the rheological properties was methodically evaluated. The self-healing capability of the syntactic foam was also assessed for healing at low and high temperatures. This study proves the viability of manufacturing multifunctional ultralightweight SMV-based syntactic foams, which are instrumental for designing ultralightweight engineering structures and devices.
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Affiliation(s)
- Siavash Sarrafan
- Department of Mechanical & Industrial
Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Guoqiang Li
- Department of Mechanical & Industrial
Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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2
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Vakil AU, Petryk NM, Du C, Howes B, Stinfort D, Serinelli S, Gitto L, Ramezani M, Beaman HT, Monroe MBB. In vitro and in vivo degradation correlations for polyurethane foams with tunable degradation rates. J Biomed Mater Res A 2023; 111:580-595. [PMID: 36752708 DOI: 10.1002/jbm.a.37504] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 12/19/2022] [Accepted: 01/13/2023] [Indexed: 02/09/2023]
Abstract
Polyurethane foams present a tunable biomaterial platform with potential for use in a range of regenerative medicine applications. Achieving a balance between scaffold degradation rates and tissue ingrowth is vital for successful wound healing, and significant in vivo testing is required to understand these processes. Vigorous in vitro testing can minimize the number of animals that are required to gather reliable data; however, it is difficult to accurately select in vitro degradation conditions that can effectively mimic in vivo results. To that end, we performed a comprehensive in vitro assessment of the degradation of porous shape memory polyurethane foams with tunable degradation rates using varying concentrations of hydrogen peroxide to identify the medium that closely mimics measured in vivo degradation rates. Material degradation was studied over 12 weeks in vitro in 1%, 2%, or 3% hydrogen peroxide and in vivo in subcutaneous pockets in Sprague Dawley rats. We found that the in vitro degradation conditions that best predicted in vivo degradation rates varied based on the number of mechanisms by which the polymer degraded and the polymer hydrophilicity. Namely, more hydrophilic materials that degrade by both hydrolysis and oxidation require lower concentrations of hydrogen peroxide (1%) to mimic in vivo rates, while more hydrophobic scaffolds that degrade by oxidation alone require higher concentrations of hydrogen peroxide (3%) to model in vivo degradation. This information can be used to rationally select in vitro degradation conditions that accurately identify in vivo degradation rates prior to characterization in an animal model.
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Affiliation(s)
- Anand Utpal Vakil
- Department of Biomedical and Chemical Engineering and BioInspired Syracuse, Institute for Material and Living Systems, Syracuse University, Syracuse, New York, USA
| | - Natalie Marie Petryk
- Department of Biomedical and Chemical Engineering and BioInspired Syracuse, Institute for Material and Living Systems, Syracuse University, Syracuse, New York, USA
| | - Changling Du
- Department of Biomedical and Chemical Engineering and BioInspired Syracuse, Institute for Material and Living Systems, Syracuse University, Syracuse, New York, USA
| | - Bryanna Howes
- Department of Chemistry, Le Moyne College, Syracuse, New York, USA
| | | | | | - Lorenzo Gitto
- SUNY Upstate Medical University, Syracuse, New York, USA
| | - Maryam Ramezani
- Department of Biomedical and Chemical Engineering and BioInspired Syracuse, Institute for Material and Living Systems, Syracuse University, Syracuse, New York, USA
| | - Henry T Beaman
- Department of Biomedical and Chemical Engineering and BioInspired Syracuse, Institute for Material and Living Systems, Syracuse University, Syracuse, New York, USA
| | - Mary Beth Browning Monroe
- Department of Biomedical and Chemical Engineering and BioInspired Syracuse, Institute for Material and Living Systems, Syracuse University, Syracuse, New York, USA
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3
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Lu C, Shen Y, Wang X, Xu S, Wang J, Yong Q, Chu F. Biomimetic ultra-strong, ultra-tough, degradable cellulose-based composites for multi-stimuli responsive shape memory. Int J Biol Macromol 2023; 226:1468-1476. [PMID: 36442569 DOI: 10.1016/j.ijbiomac.2022.11.259] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 11/12/2022] [Accepted: 11/24/2022] [Indexed: 11/27/2022]
Abstract
Fabrication of ultra-strong, ultra-tough, sustainable, and degradable bio-based composites is urgently needed but remains challenging. Here, a biomimetic sustainable, degradable, and multi-stimuli responsive cellulose/PCL/Fe3O4 composite with ultra-strong mechanical strength and ultra-high toughness was developed. To prepare the proposed composites, the soft poly(ε-caprolactone) (PCL) side chain was grafted onto the rigid cellulose backbone, then the cellulose graft copolymer (EC-g-PCL) reacted with rigid hexamethylenediamine modified Fe3O4 nanoparticle (Fe3O4-NH2) to construct the crosslinking network using MDI-50 as a crosslinker. Given by the construction of crosslinking network and the "hard" and "soft" interactive structure, the composites showed ultra-strong mechanical strength (25.7 MPa) and ultra-high toughness (107.0 MJ/m3), and the composite specimen could lift a weight of approximately 21,200 times its mass. The composites also exhibited rapid degradation ability with high degradation efficiency. In addition, the composites showed excellent thermal responsive shape memory property with a shape recovery ratio above 96 %. Most importantly, the Fe3O4 nanoparticles endowed the composites with photothermal conversion property, the composites exhibited superior NIR light-triggered shape memory capability. The EC-g-PCL/Fe3O4 composites with ultra-strong mechanical strength and ultra-high toughness have promising applications in heavy-lift, object transportation, and self-tightening knots.
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Affiliation(s)
- Chuanwei Lu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China; Institute of Chemical Industry of Forestry Products, Chinese Academy of Forestry (CAF), No 16, Suojin Wucun, Nanjing 210042, Jiangsu Province, China
| | - Yi Shen
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Xinyu Wang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Shijian Xu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Jifu Wang
- Institute of Chemical Industry of Forestry Products, Chinese Academy of Forestry (CAF), No 16, Suojin Wucun, Nanjing 210042, Jiangsu Province, China.
| | - Qiang Yong
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China.
| | - Fuxiang Chu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China; Institute of Chemical Industry of Forestry Products, Chinese Academy of Forestry (CAF), No 16, Suojin Wucun, Nanjing 210042, Jiangsu Province, China.
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Guggenbiller G, Al Balushi A, Weems AC. Poly(β‐hydroxythioether)s as shape memory polymer foams for oil sorption in aquatic environments. J Appl Polym Sci 2022. [DOI: 10.1002/app.53569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Grant Guggenbiller
- Biomedical Engineering Program, Biomolecular and Chemical Engineering Department, Russ College of Engineering Ohio University Athens Ohio USA
| | - Ali Al Balushi
- Department of Mechanical Engineering, Russ College of Engineering Ohio University Athens Ohio USA
| | - Andrew C Weems
- Biomedical Engineering Program, Biomolecular and Chemical Engineering Department, Russ College of Engineering Ohio University Athens Ohio USA
- Department of Mechanical Engineering, Russ College of Engineering Ohio University Athens Ohio USA
- Ohio Musculoskeletal and Neurological Institute, and Center for Advanced Materials Processing, Russ College of Engineering Ohio University Athens Ohio USA
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Du C, Fikhman DA, Monroe MBB. Shape Memory Polymer Foams with Phenolic Acid-Based Antioxidant Properties. Antioxidants (Basel) 2022; 11:antiox11061105. [PMID: 35740002 PMCID: PMC9219628 DOI: 10.3390/antiox11061105] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/28/2022] [Accepted: 05/30/2022] [Indexed: 02/04/2023] Open
Abstract
Phenolic acids (PAs) are natural antioxidant agents in the plant kingdom that are part of the human diet. The introduction of naturally occurring PAs into the network of synthetic shape memory polymer (SMP) polyurethane (PU) foams during foam fabrication can impart antioxidant properties to the resulting scaffolds. In previous work, PA-containing SMP foams were synthesized to provide materials that retained the desirable shape memory properties of SMP PU foams with additional antimicrobial properties that were derived from PAs. Here, we explore the impact of PA incorporation on SMP foam antioxidant properties. We investigated the antioxidant effects of PA-containing SMP foams in terms of in vitro oxidative degradation resistance and cellular antioxidant activity. The PA foams showed surprising variability; p-coumaric acid (PCA)-based SMP foams exhibited the most potent antioxidant properties in terms of slowing oxidative degradation in H2O2. However, PCA foams did not effectively reduce reactive oxygen species (ROS) in short-term cellular assays. Vanillic acid (VA)- and ferulic acid (FA)-based SMP foams slowed oxidative degradation in H2O2 to lesser extents than the PCA foams, but they demonstrated higher capabilities for scavenging ROS to alter cellular activity. All PA foams exhibited a continuous release of PAs over two weeks. Based on these results, we hypothesize that PAs must be released from SMP foams to provide adequate antioxidant properties; slower release may enable higher resistance to long-term oxidative degradation, and faster release may result in higher cellular antioxidant effects. Overall, PCA, VA, and FA foams provide a new tool for tuning oxidative degradation rates and extending potential foam lifetime in the wound. VA and FA foams induced cellular antioxidant activity that could help promote wound healing by scavenging ROS and protecting cells. This work could contribute a wound dressing material that safely releases antimicrobial and antioxidant PAs into the wound at a continuous rate to ideally improve healing outcomes. Furthermore, this methodology could be applied to other oxidatively degradable biomaterial systems to enhance control over degradation rates and to provide multifunctional scaffolds for healing.
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Current State and Perspectives of Simulation and Modeling of Aliphatic Isocyanates and Polyisocyanates. Polymers (Basel) 2022; 14:polym14091642. [PMID: 35566811 PMCID: PMC9099476 DOI: 10.3390/polym14091642] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 02/06/2023] Open
Abstract
Aliphatic isocyanates and polyisocyanates are central molecules in the fabrication of polyurethanes, coatings, and adhesives and, due to their excellent mechanical and stability properties, are continuously investigated in advanced applications; however, despite the growing interest in isocyanate-based systems, atomistic simulations on them have been limited by the lack of accurate parametrizations for these molecular species. In this review, we will first provide an overview of current research on isocyanate systems to highlight their most promising applications, especially in fields far from their typical usage, and to justify the need for further modeling works. Next, we will discuss the state of their modeling, from first-principle studies to atomistic molecular dynamics simulations and coarse-grained approaches, highlighting the recent advances in atomistic modeling. Finally, the most promising lines of research in the modeling of isocyanates are discussed in light of the possibilities opened by novel approaches, such as machine learning.
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7
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Vakil AU, Petryk NM, Shepherd E, Monroe MBB. Biostable Shape Memory Polymer Foams for Smart Biomaterial Applications. Polymers (Basel) 2021; 13:polym13234084. [PMID: 34883587 PMCID: PMC8658902 DOI: 10.3390/polym13234084] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 11/16/2022] Open
Abstract
Polyurethane foams provide a wide range of applications as a biomaterial system due to the ability to tune their physical, chemical, and biological properties to meet the requirements of the intended applications. Another key parameter that determines the usability of this biomaterial is its degradability under body conditions. Several current approaches focus on slowing the degradation rate for applications that require the implant to be present for a longer time frame (over 100 days). Here, biostable shape memory polymer (SMP) foams were synthesized with added ether-containing monomers to tune the degradation rates. The physical, thermal and shape memory properties of these foams were characterized along with their cytocompatibility and blood interactions. Degradation profiles were assessed in vitro in oxidative (3% H2O2; real-time) and hydrolytic media (0.1 M NaOH; accelerated) at 37 °C. The resulting foams had tunable degradation rates, with up 15% mass remaining after 108 days, and controlled erosion profiles. These easy-to-use, shape-filling SMP foams have the potential for various biomaterial applications where longer-term stability without the need for implant removal is desired.
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8
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Lenzi V, Ramos MMD, Marques LSA. Dissipative particle dynamics simulations of end-cross-linked nanogels. MOLECULAR SIMULATION 2020. [DOI: 10.1080/08927022.2020.1859111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Veniero Lenzi
- Center of Physics of Universities of Minho and Porto, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Marta M. D. Ramos
- Center of Physics of Universities of Minho and Porto, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Luís S. A. Marques
- Center of Physics of Universities of Minho and Porto, University of Minho, Campus de Gualtar, Braga, Portugal
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9
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The Difference in Molecular Orientation and Interphase Structure of SiO 2/Shape Memory Polyurethane in Original, Programmed and Recovered States during Shape Memory Process. Polymers (Basel) 2020; 12:polym12091994. [PMID: 32887279 PMCID: PMC7564273 DOI: 10.3390/polym12091994] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/31/2020] [Accepted: 09/01/2020] [Indexed: 12/17/2022] Open
Abstract
In order to further understand the shape memory mechanism of a silicon dioxide/shape memory polyurethane (SiO2/SMPU) composite, the thermodynamic properties and shape memory behaviors of prepared SiO2/SMPU were characterized. Dynamic changes in the molecular orientation and interphase structures of SiO2/SMPU during a shape memory cycle were then discussed according to the small angle X-ray scattering theory, Guinier’s law, Porod approximation, and fractal dimension theorem. In this paper, a dynamic mechanical analyzer (DMA) helped to determine the glass transition start temperature (Tg) by taking the onset point of the sigmoidal change in the storage modulus, while transition temperature (Ttrans) was defined by the peak of tan δ, then the test and the calculated results indicated that the Tg of SiO2/SMPU was 50.4 °C, and the Ttrans of SiO2/SMPU was 72.18 °C. SiO2/SMPU showed good shape memory performance. The programmed SiO2/SMPU showed quite obvious microphase separation and molecular orientation. Large-size sheets and long-period structures were formed in the programmed SiO2/SMPU, which increases the electron density difference. Furthermore, some hard segments had been rearranged, and their gyration radii decreased. In addition, several defects formed at the interfaces of SiO2/SMPU, which caused the generation of space charges, thus leading to local electron density fluctuations. The blurred interphase structure and the intermediate layer formed in the programmed SiO2/SMPU and there was evident crystal damage and chemical bond breakage in the recovered SiO2/SMPU. Finally, the original and recovered SiO2/SMPU samples belong to the surface fractal system, but the programmed sample belongs to the mass fractal and reforms two-phase structures. This study provides an insight into the shape memory mechanism of the SiO2/SMPU composite.
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Abstract
This paper reports the unique microstructure of polyurea foams that combines the advantages of open and closed cell polymeric foams, which were synthesized through a self-foaming process. The latter was the result of aggressive mechanical mixing of diamine curative, isocyanate, and deionized water at ambient conditions, which can be adjusted on-demand to produce variable density polyurea foam. The spherical, semi-closed microcellular structure has large perforations on the cell surface resulting from the concurrent expansion of neighboring cells and small holes at the bottom surface of the cells. This resulted in a partially perforated microcellular structure of polyurea foam. As a byproduct of the manufacturing process, polyurea microspheres nucleate and deposit on the inner cell walls of the foam, acting as a reinforcement. Since cell walls and the microspheres are made of polyurea, the resulting reinforcement effect overcomes the fundamental interfacial issue of different adjacent materials. The partially perforated, self-reinforced polyurea foam is compared to the performance of traditional counterparts in biomechanical impact scenarios. An analytical model was developed to explicate the stiffening effect associated with the reinforcing microspheres. The model results indicate that the reinforced microcell exhibited, on average, ~30% higher stiffness than its barren counterpart.
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Weems AC, Pérez-Madrigal MM, Arno MC, Dove AP. 3D Printing for the Clinic: Examining Contemporary Polymeric Biomaterials and Their Clinical Utility. Biomacromolecules 2020; 21:1037-1059. [PMID: 32058702 DOI: 10.1021/acs.biomac.9b01539] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The advent of additive manufacturing offered the potential to revolutionize clinical medicine, particularly with patient-specific implants across a range of tissue types. However, to date, there are very few examples of polymers being used for additive processes in clinical settings. The state of the art with regards to 3D printable polymeric materials being exploited to produce novel clinically relevant implants is discussed here. We focus on the recent advances in the development of implantable, polymeric medical devices and tissue scaffolds without diverging extensively into bioprinting. By introducing the major 3D printing techniques along with current advancements in biomaterials, we hope to provide insight into how these fields may continue to advance while simultaneously reviewing the ongoing work in the field.
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Affiliation(s)
- Andrew C Weems
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, U.K
| | | | - Maria C Arno
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, U.K
| | - Andrew P Dove
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, U.K
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Kumar B, Noor N, Thakur S, Pan N, Narayana H, Yan SC, Wang F, Shah P. Shape Memory Polyurethane-Based Smart Polymer Substrates for Physiologically Responsive, Dynamic Pressure (Re)Distribution. ACS OMEGA 2019; 4:15348-15358. [PMID: 31572833 PMCID: PMC6761750 DOI: 10.1021/acsomega.9b01167] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 09/02/2019] [Indexed: 06/10/2023]
Abstract
Shape memory polymers (SMPs) are an exciting class of stimuli-responsive smart materials that demonstrate reactive and reversible changes in mechanical property, usually by switching between different states due to external stimuli. We report on the development of a polyurethane-based SMP foam for effective pressure redistribution that demonstrates controllable changes in dynamic pressure redistribution capability at a low transition temperature (∼24 °C)-ideally suited to matching modulations in body contact pressure for dynamic pressure relief (e.g., for alleviation or pressure ulcer effects). The resultant SMP material has been extensively characterized by a series of tests including stress-strain testing, compression testing, dynamic mechanical analysis, optical microscopy, UV-visible absorbance spectroscopy, variable-temperature areal pressure distribution, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, differential scanning calorimetry, dynamic thermogravimetric analysis, and 1H nuclear magnetic resonance spectroscopy. The foam system exhibits high responsivity when tested for plantar pressure modulation with significant potential in pressure ulcers treatment. Efficient pressure redistribution (∼80% reduction in interface pressure), high stress response (∼30% applied stress is stored in fixity and released on recovery), and excellent deformation recovery (∼100%) are demonstrated in addition to significant cycling ability without performance loss. By providing highly effective pressure redistribution and modulation when in contact with the body's surface, this SMP foam offers novel mechanisms for alleviating the risk of pressure ulcers.
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Affiliation(s)
- Bipin Kumar
- Department of Textile Technology, Indian
Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Nuruzzaman Noor
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Suman Thakur
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Ning Pan
- Biological & Agricultural Engineering, UC Davis, Davis, California 95616, United States
| | - Harishkumar Narayana
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Siu-cheong Yan
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Faming Wang
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Parth Shah
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
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13
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Weems AC, Wacker KT, Maitland DJ. Improved Oxidative Biostability of Porous Shape Memory Polymers by Substituting Triethanolamine for Glycerol. J Appl Polym Sci 2019; 136. [PMID: 32601505 DOI: 10.1002/app.47857] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
While many aromatic polyurethane systems suffer from poor hydrolytic stability, more recently proposed aliphatic systems are oxidatively-labile. The use of the renewable monomer glycerol as a more oxidatively-resistant moiety for inclusion in shape memory polymers (SMPs) is demonstrated here. Glycerol-containing SMPs and the amino alcohol control compositions are compared, with accelerated degradation testing displaying increased stability (time to complete mass loss) as a result of the inclusion of glycerol without sacrificing the shape memory, thermal transitions, or the ultralow density achieved with the control compositions. Gravimetric analysis in accelerated oxidative solution indicates that the control will undergo complete mass loss by approximately 18 days, while lower concentrations of glycerol will degrade fully by 30 days and higher concentrations will possess approximately 40% mass at the same time. In real time degradation analysis, high concentrations of glycerol SMPs have 96% mass remaining at 8 months with 88% gel fraction remaining that that time, compared to less than 50% mass for the control samples with 5% gelation. Mechanically, low glycerol-containing SMPs were not robust enough for testing at three months, while high glycerol concentrations displayed increased elastic moduli (133% of virgin materials) and 18% decreased strain to failure. The role of the secondary alcohol, as well as isocyanates, is presented as being a crucial component in controlling degradation; a free secondary alcohol can more rapidly undergo oxidation or dehydration to ultimately yield carboxylic acids, aldehydes, carbon dioxide, and alkenes. Understanding these pathways will improve the utility of medical devices through more precise control of property loss and patient risk management through reduced degradation.
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Affiliation(s)
- Andrew C Weems
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA.,Department of Chemistry, Texas A&M University, College Station, Texas, 77843-3120, USA
| | - Kevin T Wacker
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA.,Department of Chemistry, Texas A&M University, College Station, Texas, 77843-3120, USA
| | - Duncan J Maitland
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA.,Department of Chemistry, Texas A&M University, College Station, Texas, 77843-3120, USA
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