Hong Haoqun

Effect of Interfacial Modifiers on Physical Properties and Flammability Properties of PE/Wood Composites

The ternary-monomer graft copolymers of polyethylene (GPE) were used as interfacial modifiers for recycled polyethylene (rPE)/wood flour (WF) composites. How the interfacial modifiers and WF processing methods affected the mechanical properties, thermal stability and flammability properties of the composites were investigated. Results show that the steam-braising on WF could increase the mechanical properties of the composites. The interfacial modifiers were excellent compatilizers for the rPE/WF composites that significantly increased the mechanical properties of the composites. Wood flour acted as charring agent during the combustion of the composites to improve the flame retardancy of PE/wood flour composites. Due to the improved interface compatibility between rPE and WF by GPE, the rPE/WF composites maintained excellent mechanical properties and flame retardancy even at higher filler content.

Study on the nonisothermal crystallization kinetics of ternary-monomer solid-phase graft copolymer of polypropylene

In order to discover how the grafted side chains affect the crystallization of the graft copolymers, the ternary-monomer solid-phase graft copolymers of polypropylene (PP; PPSM) were synthesized by solid-phase grafting of maleic anhydride, styrene and butyl acrylate onto PP. The Jeziorny and Mo methods were used to investigate the nonisothermal crystallization kinetics and polarizing microscope was used to study the crystalline morphology of PPSM. Results show that the grafted side chains not only promoted the heteronucleation of PP and reduced the size of spherulites but also hindered the growth of crystals resulting in the formation of imperfect crystallization region in PP. Due to the hindrance of the grafted side chains on the crystallization, the nonisothermal crystallization energy (ΔE) of PPSM calculated by the Kissinger equation is evidently higher than that of PP.