LLDPE专用料的交联行为研究

【作者】 陈文强；

【导师】 谭志勇；

【作者基本信息】 长春工业大学 ， 高分子化学与物理， 2010， 硕士

【摘要】 本文采用过氧化物交联方法对线性低密度聚乙烯/乙烯-α-辛烯共聚物进行了共混改性研究。在双螺杆挤出机中对LLDPE和POE进行低温加工时,由于较强的加工剪切作用,温度升高现象比较明显,温度不易控制。应用双螺杆挤出机进行低温加工时,主机加热的稳定时间、机头温度、投料转速和螺杆转速均对熔体温度有较大的影响。不同双螺杆挤出机螺杆的长径比也是影响加工的主要因素,通常选择螺杆长径比较小的螺杆进行加工。过氧化物交联结果表明,在过氧化物交联反应中LLDPE和POE的凝胶含量随引发剂用量、交联时间的增加而增加,在达到一定量和一定时间后即可满足交联反应要求。通过LLDPE和POE不同共混比例组成的共混物的力学性能的变化情况可以看出,LLDPE/POE随着POE在总组分中百分比的增加而冲击强度依次降低。LLDPE/POE/1.5%DCP的冲击强度与LLDPE/1.5DCP.POE冲击强度相比较有一定的升高。但升高的幅度并不十分明显。在双辊开炼机中对LLDPE/POE共混物进行共混改性。研究了工艺、配方对LLDPE/POE共混物凝胶含量的影响,以及凝胶含量与材料力学性能的关系。结果表明,LLDPE/POE共混物的凝胶含量随引发剂的用量、交联温度和交联时间的增加而增加,达到一定程度后不再增加。在170℃,30min的条件下DCP能充分分解引发交联反应,DCP用量为1.5%时,共混物的凝胶含量可以达到80%以上,再增加时凝胶含量不再增加。DCP的加入顺序对共混物的凝胶含量影响不大。共混物的凝胶含量对其动态力学行为有影响。共混物的凝胶含量对拉伸性能和硬度影响不大。更多还原

【Abstract】 In this paper the crosslinking behavior of linear low density poly ethylene (LLDPE)/ Poly (octylene ethylene) copolymer (POE) blends were studied by peroxide crosslinking.While LLDPE and POE were processed in twin screw extruder in low temperature, the rising of temperature was obviously and not easy to control due to the strong effect of shearing process.when we process in twin screw extruder at low temperature. It was more effect in melt temperature by the stabilizationg of mainframe heating、machine head temperature、feed speed and screw speed. One of the main factors during process was the different length-diameter ratio of twin screw extruder.we selected low length-diameter ratio screw stem to process generally. Peroxide crosslinking results showed that the gel fraction of crosslinked LLDPE and POE increased with the content of initiator and the vulcanization time. And the gel fraction of crosslinked LLDPE was enough at certain value and certain time.Through the change of mechanical property that blends of different blend proportion. We could see that the impact-strength of LLDPE/POE decreased with the percent of POE increasing in total constituents. Compared with the impact strength of LLDPE/1.5DCP.POE. The blend of LLDPE/POE/1.5DCP was better but the degree of rising was not obviously.The LLDPE/POE blends were studied in Shuangkun open mill. The effect of peroxide proportion and processing technology on gel fraction of crosslinked LLDPE/POE blends and the relationship between gel fraction and the mechanical properties of compound were investigated. The results showed that the gel fraction of LLDPE/POE blends increased with the content of dicumyl peroxide (DCP)、vulcanization time and the incremental of crosslinking time and reached maximum at a certain value. The gel fraction of blends showed no difference with different feeding sequence of DCP. Dynamic mechanical thermal analysis (DMTA) behavior of blends was influenced by the gel fraction of blends. The gel fraction of blends showed no obvious effect on tensile behavior of blends.更多还原