Nonisothermal and Isothermal Cold Crystallization Behaviors of Biodegradable Poly(p-dioxanone)

Abstract

Nonisothermal and isothermal cold crystallization behaviors of poly(p-dioxanone) (PPDO) were investigated by differential scanning calorimetry (DSC). There were two crystallization exothermsa major exotherm between 25 °C and 50 °C and a minor one almost unchanged at 77 °C with various heating ratesin the heating scans of PPDO during nonisothermal cold crystallization. Temperature-modulated differential scanning calorimetry (TMDSC) revealed the major crystallization exotherm in the low-temperature range to be the real cold crystallization peak, and the minor one in the high-temperature range to be the melt-recrystallization peak of crystals with lower thermal stability. Several methods, including the Avrami, Tobin, and Ozawa equations, were employed to analyze the nonisothermal cold crystallization kinetics of PPDO. The efficiencies of the Avrami and Tobin methods were compared, and the results suggest that the Avrami equation is more suitable for describing nonisothermal cold crystallization kinetics of PPDO. The activation energy for nonisothermal cold crystallization of PPDO was calculated to be 35.27 kJ/mol, using the Kissinger method. In addition, the Avrami equation was also used to describe the isothermal cold crystallization kinetics of PPDO.

Influence of thermal annealing on mechanical properties andin vitrodegradation of poly(p‐dioxanone)

“…As PDO is emerging as an attractive biodegradable polymer; however, there is still a lack of understanding in its structure–property relationships. For example, although both isothermal and nonisothermal crystallization kinetics of PDO have been studied , there is no report on its effect on mechanical and degradation properties as of yet. Furthermore, to our best knowledge, there are few reports on molecular weight measurements, mainly because of limited instrumentation capable of accommodating hexafluoroisopropanol (HFIP), which is the best solvent for high‐molecular‐weight PDO .…”

Crystallization behaviors and morphology of novel poly(octamethylene adipate-co-octamethylene succinate) and poly(octamethylene adipate)

“…The signals at 1.66 and 2.32 ppm are assigned to the methylene protons e and f of AdA, and the peak at 2.62 ppm is caused by g proton from OS unit. The exactly molar compositions of the copolymers were calculated by the following equation: (1) where F OA is the molar fraction of the OA repeating units. I f and I g are the peak intensities of the f and g methylene protons, respectively.…”

“…Until now, the crystallization behaviors, crystal structure, spherulitic morphology, and degradation of many aliphatic polyesters have been widely investigated. [1][2][3][4][5][6][7][8][9][10] Biodegradable polymers may have appropriate chemical, physical, and mechanical properties for their industry application. However, the high price and low degradation rate of them may restrict their wider application fields.…”

Nonisothermal crystallization behaviors of biodegradable double crystalline poly(butylene succinate)‐poly(ethylene glycol) multiblock copolymers

“…The investigation of the nonisothermal crystallization behavior of semi-crystalline polymers is of high technical importance as most practical processes such as injection, extrusion, and other molding is performed under nonisothermal conditions. 47 In the present study, the nonisothermal crystallization kinetics of PBS segment within PBSEG is investigated firstly. Figure 1 shows the DSC cooling curves of PBSEGs which were cooled from melt state at various rates (/).…”