应力诱导引发MAH官能化PE-LD及其对铝箔/PET复合薄膜层间剥离强度的影响

Functionalization of Low-density Polyethylene with Maleic Anhydride Through Stress-induced Initiation and Its Effect on the Peeling Strength of Al/PET Composite Film

采用提高双螺杆挤出机螺杆转速的应力诱导引发方法和添加引发剂与提高螺杆转速的复合引发方法,研究了高剪切应力作用下马来酸酐(MAH)与低密度聚乙烯(PE-LD)的官能化反应,并且考察了官能化产物PE-LD-g-MAH对铝箔/PET复合薄膜(Al/PET)T形黏合接头剥离强度的影响。结果表明,高剪切应力作用可直接引起大分子链的断链,形成大分子自由基,引发PE-LD的接枝反应;通过改变螺杆转速可有效抑制交联副反应,制得具有较高接枝率、较好熔体流动速率和较低凝胶含量的官能化产物,当螺杆转速为800 r/min时,产物的接枝率为0.71%,熔体流动速率为0.87 g/10 min,凝胶含量为0.40%;高剪切应力诱导引发法所得官能化产物可明显提高Al/PET的T形黏合接头的剥离强度,当反应温度为310℃、螺杆转速为600 r/min、三元乙丙橡胶(EPDM)含量为80%(质量分数,下同)时,可使Al/PET的T形黏合接头的剥离强度达到3.87 N/mm。

Low-density polyethylene （PE-LD） melt was grafted with maleic anhydride （MAH） in a twinscrew extruder in the presence of an initiator. By enhancing the screw rotation speed, the chains of PE-LD were scissored forming macromolecular radicals, thus promoted the grafting reaction. When the screw rotation speed was 800 r/min, a high percentage of grafting （0. 71%） and a high melt flow rate （0. 87 g/10 min）, and a low gel content （0. 40 % ） could be obtained. The functionalized product of PE-LD was blended with EPDM and was used as a hot melt adhesive. When the reaction temperature was 310 ℃, the screw rotation speed was 600 r/min, and the content of EPDM was 80 wt %, the bond strength of T-adhint of the M/PET film reached 3. 87 N/mm.