Nonisothermal Cold Crystallization Kinetics of Poly(lactic acid)/Bacterial Poly(hydroxyoctanoate) (PHO)/Talc

Abstract

The effects of bacterial poly(hydroxyoctanoate) (PHO) and talc on the nonisothermal cold crystallization behaviours of poly(lactic acid) (PLA) were analysed with differential scanning calorimetry (DSC), and the thermal stability of the samples was observed with thermal gravimetric analysis (TGA). The modified Avrami’s model was used to describe the nonisothermal cold crystallization kinetics of neat PLA and its blends. The activation energies E for nonisothermal cold crystallization were calculated by the isoconversional method of Kissinger-Akahira-Sunose (KAS). The DSC results showed that the PLA/PHO blends were immiscible in the whole studied range, and as the PHO and talc content increased, the crystallization rate of PLA accelerated, and the crystallinity of PLA in the PLA samples increased. The values of the Avrami exponent indicated that the nonisothermal cold crystallization of the neat PLA and its blends exhibited heterogeneous, three-dimensional spherulitic growth. The E values were strongly dependent on PHO and talc. The TGA results showed that the presence of PHO and talc slightly influenced the thermal stability of PLA.

Biological and physiochemical studies of electrospun polylactid/polyhydroxyoctanoate PLA/P(3HO) scaffolds for tissue engineering applications

“…4, one-step degradation was indicative for the neat PLA fibers with the onset degradation temperature at 302 °C and maximum degradation temperature at 352 °C which was in line with the previously reported study. 28 As was suggested, PLA degrades in one step due to the intramolecular transesterification reaction that occurs above 300 °C. 29 Contrary to the one-step degradation of the neat PLA, the PLA/PHO fiber blends showed two-step degradation mechanism.…”

“…The neat PLA fiber showed a single melting peak at 161.2 °C, while the cold crystallization peak appeared at 90.8 °C, as was expected. 27 These values, as well as those defined for the PLA/PHO fibers including characteristic enthalpies, are listed in Table 2. From the Fig.…”

“…29 Contrary to the one-step degradation of the neat PLA, the PLA/PHO ber blends showed two-step degradation mechanism. Taking into account that pure PHO shows maximum degradation rate at 280 °C, 30,31 the rst degradation stage is related to PHO degradation while the second stage happened at higher temperatures, and it is attributed to the degradation of PLA. In the DTGA curve of the bers with the highest PHO content, 40PLA-60PHO, additional peak at approximately 303 °C was detected coming from the 3-hydroxyhexanoate fractions contained in the PHO.…”

Synergistic effect of TiO2 nanoparticles and poly (ethylene-co-vinyl acetate) on the morphology and crystallization behavior of polylactic acid

“…Poly(lactic acid) (PLA) is a biodegradable polymer that can be produced by the fermentation of lactic acid derived from renewable resources such as cellulose and starch and was primarily chosen to address environmental issues often associated with non-biodegradable polymers. Because of its beneficial characteristics, including outstanding biodegradability, high tensile strength, and high transparency, polylactic acid (PLA) has recently received much attention [1][2][3][4][5] Despite the various benefits of PLA, its limited high modulus, low strain, and low thermal stability restrict its widespread use. Adding reinforcing fillers, especially nanofillers, to the PLA matrix is a method used to enhance mechanical and thermal properties, as well as to improve barrier qualities.…”

“…On the other hand, the blending of PLA with various elastomers [8,[12][13][14][15][16][17][18][19][20], including poly(ethylene-co-vinyl acetate) (EVA) copolymers [21][22][23][24], was employed to modify the physical-chemical properties of PLA. EVA is a copolymer made up of two homopolymer components: polyethylene and poly(vinyl acetate) (PVAc).…”