Spatial dependence of ordering process in bulk materials of polylactide and its multiple system during hygrothermal aging

Publication date: Available online 17 February 2020Source: Polymer Degradation and StabilityAuthor(s): Zhao-Bo Sun, Qiu-Yang Wei, Xu-Long Xie, Ling Xu, Xu Ji, Li Zhou, Gan-Ji Zhong, Zhong-Ming LiAbstractWith a growing availability of polylactide (PLA) intended to three-dimensional molding applications, its spatial dependence of structural evolution during hygrothermal aging needs to be further investigated, in order to evaluate the service and degradation of PLA. This work mainly focuses on the spatial dependence of ordering process in the bulk materials of PLA and PLA/poly(butylene adipate-co-terephthalate) (PBAT) multiple system during hygrothermal aging. It is the first time that the microbeam wide angle X-ray diffraction (μWAXD) combined with differential scanning calorimetry and scanning electron microscopy are utilized to quantitatively analyze the spatial dependence of ordering process in the three-dimensional samples. Interestingly, owing to the presence of substantial mesophase and the preferential penetration of water molecules, stronger diffraction intensity in the skin layer can be identified in PLA/PBAT blends at the initial stage of hygrothermal aging, meanwhile neat PLA remains a negligible crystallinity. We ascribe the accelerated crystallization in PLA/PBAT blends to the higher Xmeso (6.3–9.0%) for unaged PLA/PBAT blends. Moreover, at the initial stage of hygrothermal aging, the mesophase can act as active nuclei to promote the formation of crystal, and th...

Source: Polymer Degradation and Stability - February 18, 2020 Category: Chemistry Source Type: research