Structure–property relationships of reactively compatibilized PHB/EVA/starch blends

Abstract

a b s t r a c tA method is addressed to prepare poly(hydroxybutyrate)/poly(ethylene-co-vinyl acetate)/starch (PHB/EVA/starch) blends with fine dispersion of starch, i.e. by an in situ compatibilization in the presence of maleic anhydride (MA) and peroxide. The starch particle size is reduced from hundreds-m to sub-m after the compatibilization accompanied by an improvement in interfacial adhesion. Meanwhile, starch-in-EVA-type morphology is observed in the blends. The EVA and starch gradually changed into a (partially) co-continuous phase with increasing MA content. Consequently, toughness of the blends was improved as evidenced by an increase in elongation at break and tensile-fracture energy (work). Cavitation, fibrillation and matrix yielding are regarded as the toughening mechanism for the compatibilized blends. In addition, the T g of the EVA phase is dependent on its phase morphology in the blends while the thermal behavior of the PHB was only slightly affected by the compatibilization.

Thermal and Rheological Behavior of Binary Blends of Poly(hydroxybutyrate‐co‐hydroxyvalerate) and Poly(ethylene‐co‐vinyl acetate) with Different Vinyl Acetate Content

“…Here the dispersed phase formed by EVA65 is immersed in a PHBV matrix (Figure a), corroborating the results obtained by DSC. Such behavior was also observed by Ma et al in compatibilized PHB/EVA blends containing 60 wt% PHB, 18.2 wt% EVA, 18.2 wt% starch, and 3.6 wt% glycerol . PHBV/EVA90 blend shows a homogeneous fracture surface (Figure b), where it is not possible to distinguish more than one phase.…”

PHB/Cellulose Fibers Based Materials: Physical, Mechanical and Barrier Properties

“…Polyhydroxyalkanoates (PHAs) are well known biopolymers that can be produced microbially by a variety of microorganisms as an energy storage mechanism (Ma et al, 2014). They exhibit similar end-use properties with petroleum-derived polymers and, thus, they can potentially replace conventional thermoplastics in various applications (Chatzidoukas et al, 2013).…”

Plasticization effects of epoxidized vegetable oils on mechanical properties of poly(3‐hydroxybutyrate)

“…The melt temperature of PHB is located at about 180 °C and it can be processed at about 190 °C as higher temperatures (or longer residence times) promote chain scission with subsequent decrease in molecular weight . These problems can be overcome by using several techniques such as internal or external plasticization as well as physical blending with other polymers …”