熔融温度对PPS结晶度与结晶行为的影响

为了研究熔融温度对聚苯硫醚(PPS)结晶度与结晶行为的影响,利用差示扫描量热(DSC)仪研究了不同熔融温度制备PPS的结晶度及结晶行为的差异;利用热重(TG)分析仪研究了熔融温度对PPS成型过程中热氧交联程度的影响。结果表明,在熔融温度为300～360℃时,PPS的结晶度随熔融温度的升高先增大后减小,熔融温度为320℃时相对结晶度最大,最大值为44.6%,熔融温度为360℃时相对结晶度最小,最小值为23.3%;320℃时结晶峰强最大,峰宽最窄,后随熔融温度的升高结晶峰向低温方向移动,峰强减弱、峰宽增加。在300～360℃范围内,热失重率随着熔融温度的升高先平稳后下降。这是由于PPS分子活性、分子链的热氧交联反应随熔融温度的不同具有不同的表现形式,进而影响PPS的结晶度与结晶行为;随熔融温度的升高,PPS分子链热氧交联反应加剧,在高温下难以降解。通过控制熔融温度改变PPS的结晶度,制备具有性能差异的PPS材料,满足不同的工程应用需求。

Analysis on the Effect of Melting Temperature on Crystallinity and Crystallization Behavior of PPS

In order to study of the effects of different melting temperatures on the crystallinity and crystallization behavior of polyphenylene sulfide(PPS), the crystallinity and crystallization behavior of PPS processed by different melting temperatures were investigated by differential scanning calorimetry (DSC). The effects of different melting temperatures on the degree of thermal oxy- gen crosslinking on molding process of PPS were studied by thermogravimetric analysis (TGA). The results show that in condition of the melting temperature from 300 to 360℃,the crystallinity of PPS resin firstly increases then decreases with the melting tempera- ture increasing. The relative crystallinity reaches at the maximum value at 320℃,which is 44.6% and the minimum value is 23.3% at 360℃. A strongest and narrowest crystallization peak is obtained at 320℃. Then the peak width began increase and peak intensity decreases with the melting temperature increasing. From 300℃ to 360℃,the thermal weight loss rate of PPS firstly kept stable then decreases with the melting temperature increasing. This is due to the different manifestations of molecular activity and thermal oxy- gen crosslinking reaction of PPS molecular chains with different melting temperature,and thus affect crystallinity and crystallization behavior of PPS material. The enhancement of molecular chain’s crosslinking reaction with the increase of melting temperature, makes it difficult to thermally degrade at high ambient temperature. By controlling the melting temperature to change the crystallinity of PPS, materials with different performance properties can be obtained, to meet different engineering application requirements.