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Influence of cross-linking time on physico-chemical and mechanical properties of bulk poly(glycerol sebacate)

Piszko Paweł, Kryszak Bartłomiej, Szustakiewicz Konrad

Acta of Bioengineering and Biomechanics

2022

Vol. 24, no. 4

85--93

In the presented study, a PGS prepolymer (pPGS) was synthesized utilizing polycondensation technique (equimolar sebacic acid:glycerol ratio, 130 °C, 24 h). Subsequently, the pPGS was thermally cross-linked in vacuum oven in 130 °C for 84 and 168 h. The cylindrical and dumbbell-shaped samples were subjected for physico-chemical and thorough mechanical analysis including tensile and compressive strength evaluation as well as dynamic mechanical thermal analysis (DMTA). The study allowed for the investigation of alteration of PGS properties during cross-linking and decay of elastomeric properties over prolonged cross-linking time. Moreover, a deconvolution in FTIR analysis allowed to glimpse into the hydrogen bonding structure of the materials which weakens during the cross-linking. The obtained results can be utilized during designing PGS-based bulk materials for biomedical application where bearing mechanical loads and tuned chemical character is of vital importance.

Laser-modified PLGA for implants: in vitro degradation and mechanical properties

Kobielarz Magdalena, Tomanik Magdalena, Mroczkowska Katarzyna, Szustakiewicz Konrad, Oryszczak Magdalena, Mazur Anna, Antończak Arkadiusz, Filipiak Jarosław

Acta of Bioengineering and Biomechanics

2020

Vol. 22, no. 1

179--192

Irradiations of poly(lactic-co-glycolic acid) surface by CO2 laser lead to alterations of physicochemical properties of the copolymer. Effects of PLGA irradiations depend on the process parameters determining different cases of surface modification. Hence the main goal of presented studies was to define the influence of CO2 laser irradiation with different process parameters, inducing three cases of surface modification, on mechanical properties and topography of PLGA during degradation in the aqueous environment. Methods: Hydrolytic degradation of untreated and treated by CO2 laser thin specimens of PLGA was performed in distilled (demineralized) water. Mechanical properties of PLGA specimens before and during incubation were conducted in accordance with the PN-EN ISO 527-3:1998 standard. The pH of incubation solutions, topographies, masses and geometrical dimensions of specimens were controlled during the process. Results: During the hydrolytic degradation, gradual changes in failure mode were observed from ductile failure characteristic for untreated PLGA to brittle failure of incubated PLGA regardless of the case of induced modification. Tensile strength decreased with degradation time regardless of the case of surface modification with insignificant fluctuation Young’s moduli at the level of means. The pH of solutions for each case decreased and topography od specimens become smoother with incubation time. Conclusions: PLGA surface modification by CO2 laser below the ablation threshold (P1) and at the ablation threshold (P2) led to surface functionalization, however, irradiation above the ablation threshold (P3) caused marked degradation of PLGA and accelerated specimens disintegration during incubation in the aquatic environment.