Effect of Compatibilization on Biobased Rubber-ToughenedPoly(trimethylene terephthalate):Miscibility Morphology and Mechanical Properties

摘要

Fabrication of partially biobased poly(trimethylene terephthalate) (PTT) elastomeric blends was done via melt processing. Both natural rubber (NR) and epoxidized NR (ENR) were investigated as impact modifiers at 40 wt % loading to avoid lowering the overall biobased content of the blend system below that of the PTT alone (35% renewable content), along with maleated polybutadiene rubber (MR) and dicumyl peroxide (DCP) as reactive compatibilizers. The compatibility of the blend components was investigated using contact angle, rheometry, and scanning electron microscopy (SEM). The interfacial tensions and work of adhesions indicated that ENR was more miscible than NR in the PTT blend system, which was corroborated by the higher shear viscosity of the ENR blends and strong shear thinning behavior. Additionally, the predictive modeling of viscosity ratios on the elastomer–thermoplastic morphology was found to match the SEM micrographs with the dispersed elastomeric phase within the PTT matrix. The SEM images of the blends also establish that both the compatibilizers reduced the rubber inclusions size,though DCP hampered the impact performance as compared to the MR.In the presence of the MR, there was an increased cross-linking andobserved variation in the Fourier transform infrared peaks demonstratingchemical interactions between the maleic anhydride groups with thePTT that allowed for the impact strength to reach 137 J·m^–1 or 4.5 times that of the neat PTT, with the modulusof toughness increased by 82% and an elongation at yield of 50% becauseof the flexibility and amorphous nature of the rubber constituent.