Tensile properties and deformation by different compatibilizers in bio-based polylactide/poly(4-hydroxybutyrate) blends
writer：HQ Luo, XY Yang, QY Ding, BG Sheng, J Deng, XF Yan, Y Wu, H Chen, CW Hao, SS Yuan,* JR Zeng,* WH Zhou*
keywords：Mechanism， PLLA， P4HB
source：期刊
specific source：International Journal of Biological Macromolecules 2024, 281, 136550
Issue time：2024年
Blending chemically synthesized poly(4-hydroxybutyrate) (P4HB) with polylactide (PLLA) can overcome PLLA''s brittleness, offering fully biobased blends. However, due to low compatibility between PLLA and P4HB, the influence of compatibilizers on the morphology, structure and tensile deformation of PLLA/P4HB blends remains to be unresolved. This article introduces reactive poly(methyl methacrylate-co-styrene-glycidyl methacrylate) (MSG) and non-reactive polyformaldehyde (POM) compatibilizers to improve the compatibility between P4HB and PLLA, achieving the maximal elongation at break exceeding 300 % at 2 wt% MSG or 3 wt% POM. MSG inhibits PLLA crystallization, extending stress stability in the silver streak stage, while POM enhances crystallization, prolonging the strain-hardening stage. Small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) analysis show that pristine PLLA forms voids before fracture, and PLLA/P4HB blends cavitateat the yield point and develop crazes in the silver streak stage. MSG effectively transmits stress and delayscavitation, extending the silver streak stage, whereas POM forms a microcrystalline network, lowering the energy barrier for stretching-induced recrystallization. These findings could provide theoretical guidelines on selecting compatibilizers for different PLLA based blends.