聚氯乙烯乳胶机械稳定性

MECHANICAL STABILITY OF PVC LATEX

采用稳态剪切的方法测定聚氯乙烯（ＰＶＣ）乳胶的机械稳定性，并以临界凝结时间ｔ＿ｃ表征机械稳定性与剪切速率γ、乳胶含固率φ及温度Ｔ的关系。结果表明，随剪切速率的增大，含固率增加及温度升高，乳胶的机械稳定性均降低。根据实验数据回归出经验式：ｔ＿ｃ＝ｅｘｐ（－３４．７５－１．９４０ｌｎγ＋２２．３１φ＋１．５７２×１０￣４／Ｔ－１．１８５×１０￣４φ／Ｔ），其计算值与实验值较吻合。

The mechanical stability of polyvinyl chloride(PVC)latex has been tested by steady-state shearing method,and the critical gel time(tc)was considered as a indication of the relations among the mechanical stability,shear rate γ,solid content of latex and temperature T.It has shown that the mechanical stability of the latex will decrease as the increase of shear rate,solid content and temperature.An empirical formula was obtained through the regression of the experimental data as follows:tc=exp(-34.75-1.940 Inγ+22. 31+ 1.572×10￣4/T-1.185×10￣4 /T).The calculated results is in good accordance with the experimental data.The results of this study has a significant practical guidance for the control of gel during polymerization and avoid breaking of emulsion.