Efforts to decrease crosslinking extent of polyethylene in a reactive extrusion grafting process

Grafting of acrylic acid and glycidyl methacrylate onto low density polyeth ylene (LDPE) was performed by using a corotating twin-screw extruder. The e ffects of residence time and concentration of initiator and monomers on deg ree of grafting and gel content of grafting LDPE were studied systematicall y. Paraffin, styrene, p-benzoquinone, triphenyl phosphite, tetrachlorometha ne, and oleic acid were added to try to decrease the extent of crosslinking of LDPE. 4-hydroxyl-2,2,6,6-tetramethyl-1-piperidinyloxy (4-hydroxyl-TEMPO ) and dipentamethylenethiuram tetrasulfide were also tried to inhibit cross linking reaction of LDPE during its extruding grafting process. It was foun d that p-benzoquinone, triphenyl phosphite and tetrachloromethane were good inhibitors for crosslinking of LDPE. (C) 2000 John Wiley & Sons, Inc.