SBS辐射接枝共聚研究(II):线型SBS液固相辐射接枝MAA

Study on styrene-butadiene-styrene graft copolymerization by γ-ray radiation(II):liquid-solid phase graft of MAA onto linear SBS

利用γ射线辐射接枝法制备苯乙烯-丁二烯-苯乙烯(Styrene-Butadiene-Styrene,SBS)粉体接枝甲基丙烯酸(MAA)聚合物,讨论了单体浓度、辐照剂量、气氛及辐照状态等因素对接枝率的影响,并采用傅立叶红外光谱(FT-IR)、差示扫描量热分析(DSC)、凝胶渗透色谱(GPC)、扫描电镜(SEM)、动态剪切流变(DSR)等分析手段对接枝聚合物进行了表征。研究结果表明,平均粒径为0.2mm的线型SBS粉体在辐照剂量为12kGy、剂量率为0.75kGy/h、MAA/SBS的质量比为0.6时,可获得最大接枝率。FTIR谱出现1705cm-1处羰基的吸收峰证实了接枝聚合物的存在,分子量分布测定表明SBS?g?MAA聚合物的分子量分布变宽,动态剪切流变中接枝聚合物的粘度增大,表明单体在SBS链上有接枝链的增长;热分析曲线中聚苯乙烯嵌段的玻璃化转变温度升高,损耗因子转折温度升高,都说明单体MAA对PS嵌段的影响较大。

Graft copolymerization of methacrylic acid (MAA) onto SBS powder was studied by 60Co γ-ray irradiation. Effects of the irradiation dose, MAA concentration, and irradiation conditions on the graft yield were studied. The graft copolymer, SBS-g-MAA, was characterized by means of Fourier-transform infrared (FT-IR) spectroscopy, gel permeation chromatography (GPC), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and dynamic shear rheological (DSR). The -C=O- absorption peak at 1705cm-1 of the FT-IR spectra, and the wilder molecule number distribution of SBS-g-MAA by GPC analysis indicated that the MAA monomer had been grafted onto SBS molecular chains. The DSC analysis revealed an increased glass transition temperature of PS phase of the grafted SBS, while the DSR showed of the MAA monomer affected the PS phase of SBS more easily.