利用Flash DSC探究湿法隔膜快速降温过程结晶行为

Exploring the Crystallization Behavior of Wet Separator During Rapid Cooling Process by Flash DSC

研究了湿法隔膜超高分子量聚乙烯(UHMWPE)与白油混合体系在挤出流延过程中快速、非等温结晶行为。通过Flash DSC和常规DSC技术表征了不同固含量体系在不同冷却速率条件下微观晶体结构特性。结果表明:当冷却速率低于10^(4)K/min时,起始结晶温度随冷却速率增大而缓慢降低,得到的晶体片晶熔融温度和厚度随冷却速率增大而减小;当冷却速率高于10^(4)K/min时,起始结晶温度随冷却速率增大而迅速降低,而片晶厚度则变化不大;高的流延辊温得到的铸片晶体熔融温度高,片晶厚度大,且UHMWPE固含量越高,高、低温流延辊得到的铸片晶体熔融温度与片晶厚度差别越大。

The rapid and non-isothermal crystallization behavior of ultra-high molecular weight polyethylene(UHMWPE)and paraffin oil mixed system from separator by wet process during extrusion casting was studied.The microstructure characteristics of different solid content systems under different cooling rates were characterized using Flash DSC and conventional DSC techniques.The results show that when the cooling rate is below 10^(4)K/min,the initial crystallization temperature slowly decreases with the increase of cooling rate,and the obtained crystal melting temperature and thickness decreases with the increase of cooling rate;When the cooling rate is higher than 10^(4)K/min,the initial crystallization temperature rapidly decreases with the cooling rate,while the crystal thickness does not change much;The higher the casting roll temperature,the higher the melting temperature of crystal of the cast film,the thicker the crystal thickness,and the higher the solid content of UHMWPE,the greater the difference between the crystal melting temperature and crystal thickness of the cast film obtained by high and low temperature casting rolls.