不同相对黏度PA6的非等温结晶动力学研究

Non-isothermal crystallization kinetics of PA6 with different relative viscosity

以相对黏度(η_(r))为2.0,2.4,2.8,3.4,4.0的5种聚酰胺6(PA 6)切片为研究对象,采用差示扫描量热法测试其在不同冷却速率(∅)下的非等温结晶过程;基于Jeziorny法和Mo法对不同η_(r)的PA 6的非等温结晶动力学进行对比分析,并采用Kissinger法计算其结晶活化能(E)。结果表明:PA 6的η_(r)影响其熔体冷却成形过程中晶核的形成和晶体生长机制;随∅的增加,不同η_(r)的PA 6的起始结晶温度、结晶峰温度、结晶结束温度均有向低温区移动的趋势,结晶焓逐渐降低;基于Jeziorny法,在相同的∅下,随着η_(r)的增加,PA 6的结晶速率呈现先增后减的趋势,η_(r)为2.8的PA 6的结晶速率最高,η_(r)为2.0的PA 6的结晶速率最低;基于Mo法,η_(r)为2.8的PA 6综合表现出较高的结晶速率;由Kissinger法计算得到η_(r)为2.0的PA 6的E最高。

Using five kinds of polyamide 6(PA 6)chips with the relative viscosity(η_(r))of 2.0,2.4,2.8,3.4 and 4.0 as the research objects,their non-isothermal crystallization process was measured at different cooling rates(∅)by differential scanning calorimetry.The non-isothermal crystallization kinetics of PA 6 with differentη_(r)was analyzed by Jeziorny method and Mo method,and the crystallization activation energy(E)was calculated by Kissinger method.The results showed thatη_(r)affected the nulei formation and crystal growth mechanism of PA 6 during the process of melt cooling formation;and the initial crystallization temperature,crystallization peak temperature and crystallization end temperature of PA 6 with differentη_(r)tended to move to low temperature region,and the crystallization enthalpy gradually decreased with the increase of∅;based on Jeziorny method,the crystallization rate of PA 6 first increased and then decreased with the increase ofη_(r)at the same∅,the crystallization rate of PA 6 withη_(r)of 2.8 was the highest,while that of PA 6 withη_(r)of 2.0 was the lowest;and PA 6 withη_(r)of 2.8 showed higher crystallization rate based on Mo method,and PA 6 withη_(r)of 2.0 was the highest E calculated by Kissinger method.