Experimental and theoretical approaches for structural and mechanical properties of novel side chain LCP-PP graft coproducts
作者:Sedat ÇETİN、Behiye ÖZTÜRK ŞEN、Uğur SOYKAN、Elif Esra FIRAT、Gürcan YILDIRIM
DOI:10.3906/kim-1506-37
日期:——
The monomers p-biphenyloxycarbonylphenyl acrylate (BPCPA) and p-biphenyloxycarbonylphenyl methacrylate (BPCPMA) were synthesized by the reaction of p-acryloyloxybenzoyl chloride and p-methacryloyloxybenzoyl chloride with 4-hydroxybiphenyl, respectively, and polymerized by bulk polymerization in vacuum by using dicumyl peroxide. The graft copolymerization of the monomers onto polypropylene were carried out by bulk melt polymerization at 170 $^\circ}$C with various concentration levels of the monomers and the initiator in reaction mixtures. The content of monomers in their graft coproducts increased with monomer-initiator percentage in the reaction medium. The graft coproducts were characterized by several available experimental techniques including differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and mechanical testing. Moreover, the crucial changes in the mechanical performances pertaining to the polypropylene product were investigated by theoretical computations performed based on the density functional theory (B3LYP) with the standard 6-311++G(d,p) level of theory. According to obtained results, the mechanical properties of the graft coproducts deteriorated significantly with the grafting of the homopolymers due to the damage of the rate-dependent viscoelastic deformation or yielding, leading to enhancement in the surface energy values. At the same time, experimental evidence confirmed that the poly(BPCPA) materials exhibited much weaker secondary Van der Waals bonds than those in the poly(BPCPMA) products.
单体对二苯氧羰基苯甲酸丙烯酸酯(BPCPA)和对二苯氧羰基苯甲基丙烯酸酯(BPCPMA)分别通过对氢氧基二苯基和对丙烯酰氧基苯甲酰氯、对甲基丙烯酰氧基苯甲酰氯进行反应合成,并使用双偶氮化氧化剂在真空条件下进行聚合。单体在聚丙烯上的接枝共聚反应通过在170°C下的批量熔融聚合,使用不同浓度的单体和引发剂进行。反应体系中单体与引发剂的比例提高,接枝共聚物中单体的含量也随之增加。接枝共聚物通过多种实验技术进行表征,包括差示扫描量热法、热重分析、傅里叶变换红外光谱、扫描电子显微镜和力学测试。此外,基于密度泛函理论(B3LYP)和标准6-311++G(d,p)理论级别进行了理论计算,以研究聚丙烯产品机械性能的关键变化。根据获得的结果,由于由聚合物单体的接枝造成速率依赖的粘弹性变形或屈服的损伤,接枝共聚物的机械性能显著降低,从而导致表面能值的增加。同时,实验结果证实,聚(BPCPA)材料的次级范德华键显著弱于聚(BPCPMA)产品中的相应键。