Poly(lactic acid)/vinyl acetate ethylene blends: effect of crosslinking on their rheological, mechanical and thermal stability behavior

A bis(tert-butyl dioxy isopropyl) benzene (BIBP) was blended with 70/30 poly(lactic acid)/vinyl acetate ethylene (PLA/VAE) blend in order to improve the compatibility and properties of the blend. A series of samples with different BIBP contents were prepared by twin screw extruder. The gel fractions, rheological behaviors, morphologies, mechanical properties and thermal stability of the blends were investigated. Combined with the results of gel fractions and rheological behaviors, the gel fractions and complex viscosity gradually increased with increasing BIBP content, indicating that some crosslinked structures were formed after incorporation with BIBP. Crosslinking largely reduced the dispersed phase particle size and significantly increased the interfacial adhesion of PLA and VAE. Thus, the crosslinked structures could be considered as compatibilizers, which improved the compatibility between the two components. The mechanical properties were also improved remarkably when an appropriate content of BIBP was added. Upon addition of BIBP, the PLA/VAE blends not only were largely toughened but also exhibited some increase in the tensile strength. Moreover, shear yielding was considered as an important way for induced energy dissipation and led to a toughened blend. In addition, it was found that the introduction of BIBP resulted in an increase in the thermal stability of the blends. The output had certain reference values toward PLA modification strategy, and it may pave a route for endowing PLA materials with a specific required nature. [GRAPHICS] .

Automated summary

It was found that blending bis(tert-butyl dioxy isopropyl) benzene (BIBP) with poly(lactic acid)/vinyl acetate ethylene (PLA/VAE) blend greatly improved the compatibility and properties of the blend. The addition of BIBP led to the formation of crosslinked structures, reducing particle size and increasing interfacial adhesion. The mechanical properties and thermal stability of the blend were significantly improved with an appropriate content of BIBP.