Preparation Of OBC Graft Copolymer And Investigation On Its Compatibilization For R-PET/OBC Blends

With ethylene-octene block copolymer (OBC) as matrix, acrylic acid (AA) or methyl methacrylate (GMA) as grafting monomer, dicumyl peroxide (DCP) as initiator, styrene (St) as comonomer, the OBC-g-(AA-co-St) and OBC-g-(GMA-co-St) was prepared in HAAKE torque rheometer by the melt grafting method. The structures of the copolymers were characterized by means of FTIR. The influences of the temperature and concentrations of monomer AA or GMA, comonomer St and initiator DCP on the grafting reaction were studied. By differential scanning calorimeter (DSC), thermogravimetry (TG) test, thermal perforances of the graft copolymers were analyzed.With recycled poly(ethylene terephthalate)(r-PET) as matrix materials, OBC as toughening materials, OBC-g-(AA-co-St) or OBC-g-(GMA-co-St) as compatilizer, r-PET/OBC/OBC-g-(AA-co-St) or r-PET/OBC/OBC-g-(GMA-co-St) blends was prepared,by high-speed mixing, double screw extrusion, and injection molding. Through the tensile and impact test measurements, mechanical properties of alloy materials were tested. Using scanning electron microscopy (SEM) observed OBC phase dispersion situation and compatibility in matrix r-PET. Using DSC and dynamic thermal mechanical analysis (DMA) investigated the crystallization properties, storage modulus, loss modulus and glass transition temperature of r-PET.The results show that, by the melt grafting technology, AA or GMA was successfully grafted onto the OBC backbone. As a second monomer, St obviously improved the activity of GMA and AA, and promoted the grafting reaction. Compared with pure OBC, melting temperature of graft copolymers change wasn’t changing much, but crystallization temperature was further improved. Thermal stability and crystallization rate had certain declines. Both OBC-g-(AA-co-St) and OBC-g-(GMA-co-St) can compatibilize r-PET/OBC blending materials. OBC spheroidal particles embedded rPET base material, the phase interface was fuzzy, and the interface cohesion and compatibility obviously were improved. When the content of OBC-g-(AA-co-St) is2%, the blends’ melting temperature and crystallinity declined, storage modulus and loss modulus slightly decreased, and compared to pure r-PET, elongation at break and notched impact strength increased by316.73%and113.93%respectively, and suppleness is superior to PET/OBC blends of containing1.5%OBC-g-(GMA-co-St).