Preparation of MC Nylon Using Liquefied MDI as Activator
Huang Zhenqiang, Zhang Yanfei, Zhang Peng, Zhao Xueting, Yang Hao
School of Materials Science and Engineering, North University of China, Taiyuan 030051, China
摘要：以液化二苯甲烷二异氰酸酯(MDI)为活化剂，乙醇钠为催化剂，制备了浇铸(MC)尼龙，并对聚合过程和产物进行了测试。结果表明，MC尼龙体系存在明显的低黏度平台，且随着催化剂-活化剂用量的增加，平台期逐渐变短，聚合反应速率加快，到达放热峰值温度的时间也相应变短；在催化剂-活化剂用量恒定时，随着活性料中水分含量的增加，MC尼龙体系的聚合速率逐渐变慢，到达放热峰值温度的时间随之变长。此外，MC尼龙的力学性能和单体转化率基本不受催化剂-活化剂用量和活性料中水分含量(≤0.3 mg/g)的影响，其拉伸强度均大于85 MPa，弯曲强度均大于92 MPa，波动幅度均小于5 MPa，且单体转化率均大于98%。总之，以液化MDI作活化剂的MC尼龙体系呈现了较好的工艺稳定性，具有一定的应用价值。
Abstract：Using liquefied MDI as an activator and sodium ethoxide as a catalyst, MC nylon was prepared, and the polymerization process and products were tested. The results demonstrate that there are evident low viscosity platforms in the MC nylon system. Moreover, as the amount of catalyst-activator increases, the time corresponding to this low-viscosity platform gradually becomes shorter, the polymerization reaction rate increases, and the time required to reach the exothermic peak temperature becomes correspondingly shorter. When the amount of catalyst-activator is constant, as the moisture content in the active material increase, the polymerization rate of the MC nylon system gradually slow down, and the time required to reach the exothermic peak temperature become longer. Additionally, the mechanical properties of MC nylon and the conversion rate of monomers were basically not affected by the amount of catalyst-activator and the moisture content in the active material (≤0.3 mg/g). The tensile strength and flexural strength of the polymerization product are all greater than 85 MPa and 92 MPa, respectively. What's more, the monomer conversion rate of the system is greater than 98%. In conclusion, the MC nylon system with liquefied MDI as the activator exhibited good process stability and had certain application value.
Keywords：MC nylon; liquefied MDI; polymerization viscosity; moisture content
Huang Zhenqiang，Zhang Yanfei，Zhang Peng，et al. Preparation of MC nylon using liquefied MDI as activator[J]. Engineering Plastics Application，2020，48(7)：27-32.