摘要
用激光小角散射光度计和激光示差折光计测定了高压法乙烯-醋酸乙烯-共聚物(EVA)在甲苯、氯化苯和邻二氯苯中的表观重均分子量_aPP、第二维利系数A2和比折光指数增量dn/dc。结果表明EVA在这三种不同溶剂中的_aPP是相等的。根据Stockmayer 以及Bushuk 和Renoit等发展的共聚物光散射理论,以上结果表明所测得的表观分子量就是EVA样品的真实重均分子量,亦表明被测定的样品有均一的化学组成,这与用共聚合动力学统计方法和化学分析法测定共聚物化学组成所得的结果一致。 用Coedhart的基团贡献公式计算了EVA在邻二氯苯中dn/dc的值,与测定值比较,两者相近。
Apparent weight-average molecular weights Mapp, second vivid coefficients A2 and specific refractive index increments dn/dc of ethylene-vinyl acetate (EVA) copolymfer in three different solvents are measured with low angle laser light scattering Phytometer KMX-6 and laser differential refractial Phytometer KMX-16 to study the tric Mw and the compositional heterogeonity of EVA. It is found that the values of Mall in three different solvents are equal. According to the Bushuk and Beniet theory of light-scattering in copolymer systems it shows that the Mapp is the true Mw and the composition of EVA is rather homogeneous.The calculated value of dn/dc in O-dichloroberzene by Goedhart formula conforms with that of experiments.
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
1990年第1期89-93,共5页
Polymer Materials Science & Engineering
