硬脂酸对聚氯乙烯加工及性能的影响

The Effect of Stearic Acid on Processing and Properties of Polyvinyl Chloride

考察了硬脂酸用量对聚氯乙烯(PVC)加工及性能的影响。通过流变实验及其他表征手段研究硬脂酸的润滑效果。研究表明,在钙锌配方体系中,硬脂酸在一定添加量下呈现明显的推迟塑化作用,而在用量超过一定量又可以略微提前塑化。研究发现,在有机锡体系下,聚乙烯蜡(PE蜡)与硬脂酸存在交互作用,可以推测硬脂酸的推迟塑化效果是PE蜡与硬脂酸的协同作用带来的。硬脂酸用量增加到一定量能使混配料表观密度增大,表明混配料平均粒径减小,推测这是塑化时间缩短的原因。通过扫描电镜观察样条断面发现,随着硬脂酸用量增加,断面平整度下降,塑化程度呈下降趋势。通过对挤出管材进行性能测试,发现随着硬脂酸用量增加,拉伸强度呈下降趋势,这也表明塑化程度下降。

The effect of the amount of stearic acid on the processing and properties of polyvinyl chloride(PVC)was investigated.The lubrication effect of stearic acid was studied by rheological test and other characterization methods.It is found that in the calcium and zinc formulation system,stearic acid shows obvious delayed plasticization at a certain content,however,when the content exceeds a certain amount,it can plasticize slightly in advance.The results show that under the system of organotin,there is interaction effect between polyethylene(PE)wax and stearic acid.It can be inferred that the delayed plasticizing effect of stearic acid is introduced by the synergistic effect of PE wax and stearic acid.When the dosage of stearic acid exceeds a certain amount,the apparent density of PVC compounds increases,which indicates the particle size decreasing.It is speculated that this is the reason for the shortening of fusion time.By scanning electron microscopy(SEM),it is found that with the amount of the stearic acid increases,the morphology of the fracture surface becomes uneven which means the decrease of the plasticization degree.By testing the performance of the extruded pipe,it is found that with the amount of stearic acid increases,the tensile strength decreases,which means the decrease of the plasticization degree.