P-benzofenonoksikarbonilfenil akrilatın yüksek yoğunluklu polietilen üzerine aşı polimerizasyonu

The monomer, p-benzophenoneoxycarbonylphenyl acrylate (BPOCPA) was synthesized by condensation reaction of p-acryloyloxybenzoyl chloride (ABC), prepared by refluxing p-acryloyloxybenzoic acid (ABA) in thionyl chloride, with p-hydroxybenzophenone (HBP). The synthesis of monomer was studied by trying various methods, and the maximum yield, 57%, was achieved by refluxing ABC and HBP in xylene. Poly(p-benzophenoneoxycarbonylphenyl acrylate), poly(BPOCPA), was obtained by solution and bulk melt polymerization by the initiation of dicumyl peroxide (DCP).The graft copolymerization of the monomer onto high density polyethylene (HDPE) was successfully conducted with bulk melt polymerization. The graft copolymerization was investigated at varying concentrations of BPOCPA in the reaction mixture (5%, 10%, 15%, 20%, 30%, and 40%) and at constant reaction temperature (140°C). The amount of grafting increased with increasing concentration of the monomer and reached the maximum, 14.2% poly(BPOCPA), at 30% BPOCPA in the reaction medium, and followed by a considerable decrease reducing to 5.79% poly(BPOCPA) at 40% BPOCPA. The maximum % grafting (percentage of grafted poly(BPOCPA) with respect to total poly(BPOCPA) in the product) was observed to be 85.41% at 10% BPOCPA mixture.Poly(BPOCPA) and the graft coproducts were characterized by several techniques, DSC, SEM, FTIR, TG/IR systems and mechanical testing. In DSC studies, the crystalline melting temperature of poly(BPOCPA) was observed at 231°C, whereas, among the graft coproducts, it was detected only in the sample with 39.1% poly(BPOCPA) at 235°C.The decomposition mechanism of poly(BPOCPA) and graft coproducts were studied by TG/IR. The polymers degraded predominantly by the decomposition of side groups giving mainly carbondioxide and the compounds containing phenolic and vinylic groups.The mechanical properties of the graft coproducts studied at room temperature. An explicit improvement was detected particularly in tensile strength and modulus. The maximum tensile strength and modulus were found as 26.0 and 605 MPa, respectively, revealed with the sample containing 9.32% poly(BPOCPA). The impact strength of the products increased initially with the percentage of poly(BPOCPA), and the maximum strength, 52.39 kJm-2, was achieved with the sample including 19.90% poly(BPOCPA), then followed by a dramatic decrease.The tensile and impact fractured surfaces of the products studied by scanning electron microscopy (SEM) showed homogeneous structure without any phase separation. At low contents of poly(BPOCPA) the samples were mainly ductile while at high percentages they displayed brittle nature, with an increasing trend with the content.Anahtar Kelimeler: Polietilen, p-benzofenonoksikarbonilfenil akrilat, poli(pbenzofenonoksikarbonilfenil akrilat), yan-zincir sıvı kristal polimerler, aşı kopolimerizasyonu