Guangfeng Wu

Toughening of polylactide with epoxy-functionalized methyl methacrylate–butyl acrylate copolymer

Glycidyl methacrylate-functionalized methyl methacrylate–butyl acrylate (GACR) core–shell structure copolymers were synthesized to toughen polylactide (PLA). With an increase in GACR content, the PLA/GACR blends showed decreased tensile strength and modulus; however, the elongation at break and the impact strength were significantly increased compared with that of PLA. The brittle fracture of neat PLA was gradually transformed into ductile fracture by the addiction of GACR. From dynamic mechanical analysis, the rigidity of the PLA/GACR blends was decreased with the increase of GACR content. The addition of GACR decreased the degree of crystallinity of PLA. The GACR was found to aggregate to form clusters with size increasing with increasing GACR content by transmission electron microscope analysis. The clusters dispersed in PLA matrix uniformly. It was found that PLA demonstrated large area, plastic deformation (shear yielding) and cavities in the blend upon being subjected the tensile and impact tests, which was an important energy-dissipation process and led to a toughened and transparent blend.

Toughening of Poly(ethylene terephthalate) and Optimizing of the Compatibilization Between PET and EPDM by Functionalized EPDM

Ethylene-propylene-diene elastomer (EPDM), which was grafted with glycidyl methacrylate (GMA) by reactive blending, was used as modifier to toughen poly(ethylene terephthalate) (PET) and enhance the compatibility of PET/EPDM blends. Mechanical properties showed that brittle ductile transition was observed in PET/EPDM-g-GMA blends with the rubber content over 20 wt.%. The introduction of EPDM-g-GMA increased the mechanical properties of the PET/EPDM blends and decreased the particle size of EPDM dispersed phase. DSC analysis showed that the introduction of EPDM-g-GMA made the crystallization of PET difficult. DMA results showed that the compatibility of PET and EPDM phase was improved by EPDM-g-GMA.

Polyamide-6/montmorillonite nanocomposites toughened with ABS-g-MA core-shell structural particles

Abstract Polyamide-6 (PA6)/montmorillonite (MMT) nanocomposites were prepared via melt compounding. Maleated acrylonitrile-butadiene-styrene (ABS-g- MA) core-shell structural rubber particles were first introduced to toughen PA6/MMT nanocomposites. Before melt intercalation, MMT was treated with an organic surfactant agent. XRD and TEM results showed that MMT platelets were completely exfoliated in the PA6 matrix. And when the core-shell rubber particles were introduced into the nanocomposites, they were well dispersed in the matrix. Tensile and impact tests showed that a small amount of MMT could increase the yield strength but sacrifice the toughness. However when core-shell rubber particles were added into the nanocomposites, the tensile ductility and impact strength improved greatly. It was reasonable to say that the addition of core-shell particles could make the balance of the stiffness and toughness of nanocomposites.