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Aliotta L, Gigante V, Lazzeri A. Analytical Modeling of Stress Relaxation and Evaluation of the Activation Volume Variation: Effect of Temperature and Plasticizer Content for Poly(3-hydroxybutyrate-3-hydroxyvalerate). ACS OMEGA 2022; 7:23662-23672. [PMID: 35847325 PMCID: PMC9280768 DOI: 10.1021/acsomega.2c02284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In this study, stress-relaxation tests that have been carried out at different temperatures (quite below the heat deflection temperature) on a poly(3-hydroxybutyrate-3hydroxyvalerate) (PHB-HV) matrix containing different amounts of the acetyl tributyl citrate plasticizer (added at 5 and 10 wt %) are investigated. The analytical modeling of the stress relaxation behavior by the coupling of Eyring's approach and the Guiu and Pratt model is successful. The activation volume results achieved are very interesting; in fact, not only the dependence of the activation volume from temperature is confirmed (and it resulted in dependence from the α' relaxation temperature) but also, for the first time, the dependence of the activation volume from the plasticizer content is shown. In particular, the presence of a linear relationship between the activation volume and the plasticizer volume content is observed.
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Affiliation(s)
- Laura Aliotta
- University
of Pisa, Department of Civil and Industrial Engineering, Via Diotisalvi, 2, Pisa 56122, Italy
- Interuniversity
National Consortium of Materials Science and Technology (INSTM), Via Giusti 9, Florence 50121, Italy
| | - Vito Gigante
- University
of Pisa, Department of Civil and Industrial Engineering, Via Diotisalvi, 2, Pisa 56122, Italy
- Interuniversity
National Consortium of Materials Science and Technology (INSTM), Via Giusti 9, Florence 50121, Italy
| | - Andrea Lazzeri
- University
of Pisa, Department of Civil and Industrial Engineering, Via Diotisalvi, 2, Pisa 56122, Italy
- Interuniversity
National Consortium of Materials Science and Technology (INSTM), Via Giusti 9, Florence 50121, Italy
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Hoddy B, Ahmed N, Al-lamee K, Bullett N, Bressloff NW. Exploring a parallel rheological framework to capture the mechanical behaviour of a thin-strut polymeric bioresorbable coronary scaffold. J Mech Behav Biomed Mater 2022; 130:105154. [DOI: 10.1016/j.jmbbm.2022.105154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/10/2021] [Accepted: 02/27/2022] [Indexed: 11/29/2022]
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Optimisation on Thermoforming of Biodegradable Poly (Lactic Acid) (PLA) by Numerical Modelling. Polymers (Basel) 2021; 13:polym13040654. [PMID: 33671769 PMCID: PMC7926767 DOI: 10.3390/polym13040654] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/12/2021] [Accepted: 02/17/2021] [Indexed: 11/16/2022] Open
Abstract
Poly (lactic acid) (PLA) has a broad perspective for manufacturing green thermoplastic products by thermoforming for its biodegradable properties. The mechanical behaviour of PLA has been demonstrated by its strong dependence on temperature and strain rate at biaxial deformation. A nonlinear viscoelastic model by the previous study was employed in a thermoforming process used for food packaging. An optimisation approach was developed by achieving the optimal temperature profile of specimens by defining multiple heating zones based on numerical modelling with finite element analysis (FEA). The forming process of a PLA product was illustrated by modelling results on shape evolution and biaxial strain history. The optimal temperature profile was suggested in scalloped zones to achieve more even thickness distribution. The sensitivity of the optimal results was addressed by checking the robustness under perturbation.
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Higuchi J, Fortunato G, Woźniak B, Chodara A, Domaschke S, Męczyńska-Wielgosz S, Kruszewski M, Dommann A, Łojkowski W. Polymer Membranes Sonocoated and Electrosprayed with Nano-Hydroxyapatite for Periodontal Tissues Regeneration. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:E1625. [PMID: 31731775 PMCID: PMC6915502 DOI: 10.3390/nano9111625] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/12/2019] [Accepted: 11/13/2019] [Indexed: 01/21/2023]
Abstract
Diseases of periodontal tissues are a considerable clinical problem, connected with inflammatory processes and bone loss. The healing process often requires reconstruction of lost bone in the periodontal area. For that purpose, various membranes are used to prevent ingrowth of epithelium in the tissue defect and enhance bone regeneration. Currently-used membranes are mainly non-resorbable or are derived from animal tissues. Thus, there is an urgent need for non-animal-derived bioresorbable membranes with tuned resorption rates and porosity optimized for the circulation of body nutrients. We demonstrate membranes produced by the electrospinning of biodegradable polymers (PDLLA/PLGA) coated with nanohydroxyapatite (nHA). The nHA coating was made using two methods: sonocoating and electrospraying of nHA suspensions. In a simulated degradation study, for electrosprayed membranes, short-term calcium release was observed, followed by hydrolytic degradation. Sonocoating produced a well-adhering nHA layer with full coverage of the fibers. The layer slowed the polymer degradation and increased the membrane wettability. Due to gradual release of calcium ions the degradation-associated acidity of the polymer was neutralized. The sonocoated membranes exhibited good cellular metabolic activity responses against MG-63 and BJ cells. The collected results suggest their potential use in Guided Tissue Regeneration (GTR) and Guided Bone Regeneration (GBR) periodontal procedures.
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Affiliation(s)
- Julia Higuchi
- Laboratory of Nanostructures, Institute of High Pressure Physics, Polish Academy of Sciences, 01142 Warsaw, Poland; (B.W.); (A.C.); (W.Ł.)
- Faculty of Materials Science and Engineering, Warsaw University of Technology, 02507 Warsaw, Poland
- Laboratory for Biomimetic Membranes and Textiles, Empa Swiss Federal Laboratories for Materials Science and Technology, 9014 St. Gallen, Switzerland
| | - Giuseppino Fortunato
- Laboratory for Biomimetic Membranes and Textiles, Empa Swiss Federal Laboratories for Materials Science and Technology, 9014 St. Gallen, Switzerland
| | - Bartosz Woźniak
- Laboratory of Nanostructures, Institute of High Pressure Physics, Polish Academy of Sciences, 01142 Warsaw, Poland; (B.W.); (A.C.); (W.Ł.)
| | - Agnieszka Chodara
- Laboratory of Nanostructures, Institute of High Pressure Physics, Polish Academy of Sciences, 01142 Warsaw, Poland; (B.W.); (A.C.); (W.Ł.)
- Faculty of Materials Science and Engineering, Warsaw University of Technology, 02507 Warsaw, Poland
| | - Sebastian Domaschke
- Experimental Continuum Mechanics, Empa Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland;
- Department of Mechanical and Process Engineering, Institute for Mechanical Systems, ETH Zürich, 8092 Zürich, Switzerland
| | - Sylwia Męczyńska-Wielgosz
- Centre for Radiobiology and Biological Dosimetry, Institute of Nuclear Chemistry and Technology, 03195 Warsaw, Poland;
| | - Marcin Kruszewski
- Department of Molecular Biology and Translational Research, Institute of Rural Health, 20090 Lublin, Poland;
| | - Alex Dommann
- Department Materials meet Life, Empa Swiss Federal Laboratories for Materials Science and Technology, 9014 St. Gallen, Switzerland;
| | - Witold Łojkowski
- Laboratory of Nanostructures, Institute of High Pressure Physics, Polish Academy of Sciences, 01142 Warsaw, Poland; (B.W.); (A.C.); (W.Ł.)
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