软聚合物胶粒在3种反离子作用下的团聚融合行为  

Aggregation and Coalescence Behavior of Soft Polymer Colloid Induced by Three Kinds of Counterions

作　　者：魏丹 伍春娴 蒋赣 叶友爱 黄洪[2] 司徒粤 Wei Dan;Wu Chunxian;Jiang Gan;Ye Youai;Huang Hong;Situ Yue(School of Chemistry and Chemical Engineering,Guangdong Pharmaceutical University,Zhongshan,Guangdong 528458,China;Guangdong Provincial Key Lab of Green Chemical Product Technology,South China University of Technology,Guangdong,Guangzhou 510640,China)

机构地区：[1]广东药科大学医药化工学院,广东中山528458 [2]华南理工大学,广东省绿色化学产品技术重点实验室,广州510640

出　　处：《涂料工业》2020年第12期19-26,共8页Paint & Coatings Industry

基　　金：国家自然科学基金(21802026);广东省绿色化学产品技术重点实验室开放基金(GC201818)。

摘　　要：选用一种丙烯酸酯共聚物为研究对象,采用广角光散射仪的动态光散射和静态光散射方法研究其胶粒在反离子(H^+、Na^+和Mg^2+)作用下的团聚和融合行为。研究发现:在3种反离子作用下,在DLCA(扩散控制团聚)条件下,团聚体分形维数Df的值均在1. 80左右,说明胶粒在DLCA条件下没有发生融合;而在RLCA(反应控制团聚)条件下,各反离子在3种不同浓度下诱导所得的3组团聚体的平均旋转半径对无因次时间曲线、3组平均水力学半径对无因次时间曲线均在团聚实验刚开始时发生重叠,但随着团聚过程的进行,曲线不再重叠,说明胶粒在RLCA条件下发生了融合;然后在胶体中加入占固体总质量0. 70%的表面活性剂SDS(十二烷基硫酸钠),在3种反离子的作用下得到的胶粒的双颗粒形成速率常数k1,1均随时间的增加而减小,更进一步验证此时胶粒发生了融合。不管是否加入SDS,pH相同时,3种离子对胶粒诱导失稳的作用大小为:Na^+最稳定,H^+次之,Mg^2+作用体系最不稳定,而当pH<3时,由于胶粒表面聚丙烯酸电解质刷的LEA效应的影响,加入H^+的体系稳定性最差。An acrylate copolymer is chosen as investigated system,dynamic light scattering and static light scattering are used to investigate its aggregation and coalescence behavior induced by counterions(H^+,Na^+and Mg^2+). It’s found that all the values of fractal dimension Df are around 1. 80 under diffusion limited coagulation(DLCA)condition induced by all the three counterions,which indicates no coalescence occurs for the colloids under DLCA condition. However,when it undergoes reaction limited coagulation(RLCA),the evolution of the radius of gyration and hydrodynamic radius as a function of dimensionless time do shift closer at the initial stage,at later times they do not collapse to form a master-curve under three counterion concentrations for each counterion,which means coalescence occurs for the colloids under RLCA condition. Then,to demonstrate the occurrence of coalescence under RLCA condition,we have added 0. 7%(with respect to polymer mass)SDS(Sodium Dodecyl Sulfate)to the given colloidal system,we find the obtained doublet formation rate constants,K1,1,decrease and the Fuchs stability ratios,W,increase as time increases for all the aggregation induced by the three counterions,which further confirms the occurrence of coalescence. For all the conditions with and without SDS,when the pH values are close,the colloidal system added Na+is more stable than the systems added H^+ and Mg^2+,the system added Mg^2+is the most instable. However,the stability of the system added H^+ is the most instable at pH<3 because of LEA(Local Electroneutrality) effects induced by the polyelectrolyte brushes of poly(acrylic acid).

关 键 词：聚合物胶粒 反离子 光散射 团聚 融合 

分 类 号：TQ630.7[化学工程—精细化工]