悬浮聚氯乙烯对增塑剂吸收的时温特性

测定了悬浮聚氯乙烯（S-PVC）树脂对增塑剂不同温度下的吸收量,采用扫描电镜表征了S-PVC不同增塑剂吸收条件下的结构形态。结果表明：S-PVC颗粒由多级粒子聚集而成,增塑剂主要通过各级粒子聚集体间的间隙沟槽进入PVC粒子内部完成润展与溶胀,S-PVC对增塑剂的吸收是具有时间和温度依赖性的四步吸收非定态过程。其吸收包括树脂颗粒间隙润展吸收缓慢的“第1诱导期”,聚集粒子间隙润展溶胀吸收加快的“第1溶胀期”,初级粒子间润展吸收速率缓慢的“第2诱导期”,以及分子链间溶胀吸收的“第2溶胀期”。温度越高诱导期越短,

Effect of Time and Temperature on Plasticizer Absorption of Suspension Poly (vinyl chloride) Resin

Plasticizer absorption of suspended poly(vinyl chloride) (S-PVC) were determined under various time and temperature. The morphology of S-PVC grains under different plasticizer absorption conditions was characterized by scanning electron microscopy (SEM). The results showed that S-PVC grains were composed of multilevel particles, and there were grooves and pore channels among these particles. The S-PVC grains were spread and swelled by plasticizers entering through those grooves. The plasticizer adsorption of S-PVC which depended on temperature and time was a four-step unsteady process, named "first induction period", "first swelling period", "second induction period", and "second swelling period". At the "first induction period", the grooves of S-PVC grains were slowly wetted and spread by plasticizers; the pores among the agglomerates were swelled with an accelerated absorption at the "first swelling period"; while at the "second induction period", the intervals among the primary particles were slowly swelled after a swelling equilibrium; and at the "second swelling period", the space between molecular chains were rapidly occupied and swelled by plasticizers. Shorter induction period and higher swelling rates were gained at higher temperature.