本体聚合稀土异戊橡胶的加工性能

PROCESSABILITY OF POLYISOPRENE BULK POLYMERIZED WITH RARE EARTH CATALYST

对2L釜合成的5个本体聚合稀土异戊橡胶(LnIR)胶样([η]=2.38～8.10 dL/g)的辊筒行为、挤出行为,硫化特性和硫化胶性能进行了研究。结果表明,LnIR具有明显的素炼降解行为,混炼辊筒温度不宜低于70℃,混炼行为与NR和溶液聚合钛系异戊橡胶(IR-10)相当,在110～130℃时,胶料的挤出性能可达良级;口型膨胀(B)位随温度和生胶[η]的增大而略有增加,在[η]相同时,B值与IR-10胶料相近。但小于NR胶料。硫化湿度为143℃时,LnIR硫化胶的性能除拉伸强度和扯断伸长率外,其他均对硫化时间不敏感,从综合性能考虑,硫化时间应为20～40min,LnIR硫化胶的拉伸强度和撕裂强度稍低于IR-10和NR硫化胶,而回弹性、低温性能、生热和抗湿滑性等均优于或相当于后两者。为获得良好综合性能的硫化胶。LnIR[η]应为4.0～6.0dL/g。

The mill behavior , extrudability , cure characteristics and vulcanizates properties for five kinds of samples ([η] = 2.38 - 8.10 dL/ g) of poly-isoprene bulk polymerized with rare earth catalyst ( LnIR) were studied . The results showed that there was obvious degradation under the shear stress for LnIR , and the mixing temperature can not be lower than 70°C . The filler absorption of LnIR was easy and the milled sheets were fine same as those of NR and IR-10 .The extrusion properties of vulcanizates were fine at 100 - 130°C independence of their original [η] , but the die swell (B) increased with increasing [η] and temperature . At the same [η] ,the B value of LnIR was smaller than that of NR ,but equal to that of IR-10.In balance ,20-40 min of curing time at 143°C was suitable . The tensile strength , tear strength and hardness of LnIR vulcanizates werelower than those of IR- 10 and NR ,which related to its slightly low cis- 1,4 content in molecular chains .With increasing the original [η] of LnIR ,the modulus at 300% elongation and tensile strength of its vulcanizates increased obviously , the resilience and hardness increased slightly , and the elongation at break appeared a peak at [η] 5.0dL/g.The heat build-up, low temperature coefficient and wet skid resistance of LnIR vulcanizates increased slightly with increasing [η] , which were better than those of IR-10 and NR . For good properties of LnIR vulcanizates , the [η] of LnIR was suitable in the range of 4.0-6.0dL/g.