应力诱导引发HDPE/EPDM官能化反应及其对复合薄膜Al/胶层层间剥离强度的影响

Functionalization of HDPE/EPDM blend with maleic anhydride through stress-induced initiation and its effect on peeling strength of PE/Al multilayer film

采用提高双螺杆挤出机螺杆转速的高剪切应力诱导引发方法和添加引发剂与提高螺杆转速复合诱导方法,研究高密度聚乙烯(HDPE)、三元乙丙橡胶(EPDM)共混物与马来酸酐(MAH)的官能化反应及产物(HDPE/EPDM)-g-MAH对复合薄膜A l/胶层层间剥离强度的影响.研究结果表明:双螺杆挤出机的高螺杆转速、高剪切应力作用可直接引起大分子链的断链反应,形成大分子自由基,引发HDPE/EPDM共混物的官能化反应;挤出反应温度越高、螺杆转速越快,则官能化产物接枝(嵌段)率的提高越显著;添加少量引发剂具有进一步促进官能化反应的作用,官能化反应过程易控制;官能化产物(HDPE/EPDM)-g-MAH的接枝率越高,熔体流动性越好,复合薄膜A l/胶层层间剥离强度越高.在310℃的反应温度和800 r/m in的螺杆转速条件下,25 mm宽的复合薄膜A l/胶层层间剥离强度可达145 N.

The funetionalization reaction of high density polyethylene （HDPE）/ethylene-propylene-diene monomer rubber （EPDM） blend with maleic anhydride （MAH） in melt state were investigated through the high shear stress-induced initiation by increasing the screw rotation speed of twin-screw extruder and through a compounded initiation by adding a certain initiator and increasing the screw rotation speed. The results showed that the increasing of the screw rotation speed could stress-induce the scission of the HDPE/EPDM blend molecule chains, decrease the molecular weight of the products and increase their percentage of grafting and the melt flow rate. The cross-linking side reaction could be suppressed or avoided through adjusting the screw rotation speed and the reaction temperature. The peeling strength of Al/PE multilayer film was improved by increasing the screw rotation speed and reaction temperature or adding some peroxide initiator during the meh reaction extrusion. Under the conditions of 310℃ and 800 r/min, The bond strengths of the 25 mm wide T-adhint of AL/PE muhilayer film improved by the product could reach 145 N.