摘要
葡聚糖凝胶微珠表面形态存在粒子凝集和表面粗糙两种不良情况。粒子凝集的原因是分散剂聚醋酸乙烯酯(PVAc)在碱性条件下水解导致亲水性增强,以及交联反应的中间产物具有絮凝作用。另外,交联后粒子粘度增大也可导致凝集。葡聚糖微珠表面粗糙是由于后处理时PVAc的微小附着物没有从微珠表面完全除去而造成的。作者采取低温分散、交联,分步加入交联剂和调节搅拌速度等控制手段,有效地解决了上述问题。
The unsatisfactory appearance of the dextran beads consists in particle aggreg ation and rough surfaces. The authors prove that the main reason of the particle aggregation is the hydrolysis of the dispersing agent, polyvinyl acetate (PVAc), throgh which the hydro-philicity of PVAc increase and the flocculation tendency of the intermediates of the crosslin-king reaction. Rise in viscosity of the beads as a result of crosslinking could also cause the particle aggregation. The surfaces of beads become rough because PVAc failed to be removed from the surfaces after crosslinking. These problems can be solved through the control of the dispersion and crosslinking temperature, the agitation rate and the feeding manner of the cross-linking agent.
关键词
葡聚糖
凝胶
微珠
交联
表面形态
aggregate
dextran
dispersion
surface states
flocculation
gel
microbeads
crosslinking
