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Tuning the mechanical properties and degradation properties of polydioxanone isothermal annealing

Polydioxanone (PPDO) is synthesized by ring-opening polymerization of p-dioxanone, using stannous octoate as the catalyst. The polarized optical micrograph (POM) shows thes pherulite growth rate of PPDO decreases with an increase in the isothermal crystallization temperature. PPDO is compression-molded into bars, and PPDO bars are subjected to isothermal annealing at a range of temperatures (Ta = 50, 60, 70, 80, 90, and 100 °C), and correspond to three different annealing times (ta = 1h, 2h, 3h). The effect on PPDO is investigated by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). | Turkish Journal of Chemistry Turk J Chem 2020 44 1430-1444 http journals.tubitak.gov.tr chem TÜBİTAK Research Article doi 10.3906 kim-2006-55 Tuning the mechanical properties and degradation properties of polydioxanone isothermal annealing 1 2 1 2 1 1 2 1 2 1 2 1 Xiliang LIU Shaomin FENG Xin WANG Jin QI Dong LEI Yadong LI Wei BAI 1 Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu P.R. China 2 University of Chinese Academy of Sciences Beijing P.R. China Received 22.06.2020 Accepted Published Online 11.08.2020 Final Version 26.10.2020 Abstract Polydioxanone PPDO is synthesized by ring-opening polymerization of p-dioxanone using stannous octoate as the catalyst. The polarized optical micrograph POM shows thes pherulite growth rate of PPDO decreases with an increase in the isothermal crystallization temperature. PPDO is compression-molded into bars and PPDO bars are subjected to isothermal annealing at a range of temperatures Ta 50 60 70 80 90 and 100 C and correspond to three different annealing times ta 1h 2h 3h . The effect on PPDO is investigated by using differential scanning calorimetry DSC thermogravimetric analysis TGA X-ray diffraction XRD and scanning electron microscopy SEM . With an increase in Ta and ta the grain size and the degree of crystallinity also increase. Meanwhile the tensile strength is significantly improved. The PPDO bars 90 C 2 h reach the maximum crystallinity 57.21 and the maximum tensile strength 41.1 MPa . Interestingly the heat treatment process does not result in serious thermal degradation. It is observed that the hydrolytic degradation of the annealed PPDO is delayed to some extent. Thus annealed PPDO might have potential applications particularly in the fields of orthopedic fixation and tissue engineering. Key words Polydioxanone PPDO isothermal annealing mechanical properties hydrolytic degradation in vitro 1. Introduction With the rapid development of agriculture medicine and food packaging people are .