Study On Reactive Extrusion Of Polyolefin

On the basis of present research results on the reactive extrusion of polyolefin both at home and abroad, the author chose three typical reaction extruding systems, that is Polyethylene (PE) /Dicumyl Peroxide (DCP) /Maleic Anhydride (MAH), Polypropylene (PP) / Dicumyl Peroxide (DCP) /Maleic Anhydride (MAH), Polyethylene (PE) IDicumyl Peroxide (DCP) / Vinyl Triethoxy Silane (VTES), as the research target to study reaction extruding grafts in the single, two-screw extruder and 1-Iaake Plasticorder. The suitable reaction conditions are determined by thermal analysis for grafting systems via reactive extrusion technology. The grafted structure and grafted ratio are determined and tested by infrared spectrometry and chemical tritration method. The reaction mechanism, by-reaction inhibition, effect of initiator, and monomer on grafted products are studied extensively. Polyethylene grafted with maleic anhydride, as the hot melt adhesive for the aluminum-plastics compound pipe, is also studied as a goal for engineering application. According to study polyethylene grafted with maleic anhydride, author found out: (1) PE/DCP reaction extruding system presents typically cross-linking results, which shows the Melt Index (MI) dropping with increasing of DCP. The sequence is followed as LDPE>LLDPE> HDPE. Electron Donor Agent (EDA) has no inhibiting ability to the system; (2) For the PE/DCP/MAH reaction extruding grafted system, MI dropped, and grafted ratio (Gx) rised with the increase in DCP. MI increases, and then decreases, but Ox increases with the increase in MAH. (3) A new view of reaction mechanism of polyethylene grafted maleic anhydride was put forward based on experiment results. (4) EDA has obvious inhibition ability to the cross-linking by-reaction of PE grafted MAH ,which can show MI increase and stabilization with the EDA increasing. On the study of polypropylene grafted maleic anhydride, author finds: (1) PP/DCP reaction extruding system presents typically degradation results, which can be indicated by MI market increase with the DCP increasing. EDA has no inhibiting ability to the degradation; (2) For the PP/DCP/MAH reaction extruding grafted system, MI increases and Gx decreases with the DCP increasing, MI decreases andGx increases with the MAH increasing. The degradation of PP is the primaryby-reaction which can influence gfafted reaction. The degradation of PP can beenhance following the DCP increasing or be reduce wth the MAH increasing. (3)EDA and Styrene (St) can be used to reduce the degradation of PP grafted MAH, butthey can also reduce the grafted ratio.For the polyethylene (PEX) cross-linked with saline,made by reactionextruding, using two step methods, author finds: (l) Gel fraction of PE increaseswith the increasc in DCP or VTES. But the geI fraction can be stabilized graduallywhen the DCP or VTES increases to certaln extend. CataIyst (dibutyl tindilaUrat,DBTDL) can influence the time to the maximum gel fraCion. (2) For threePEX of different density polyethylene, LDPE,LLDPE and HDPE, the sequence ofgel fraction is LDPEX> LLDPEX>HDPEX. The PEX o f 7 7 % gel fracti on has beenmade by blending of HDPE and LLDPE (80/20), which has excellentcomPrehension properties. (3) Anong several suitable technique factors, whichinfiuence the properties of PEX, gralling reaction tempef8thes and screw rotationalspeed are the most impobot factOrs. The gel fraction of final products could beimProved through increasing tempehe and humidity of cross-linking reaction anddecreasing the thickness of products properlyOn the aPPlication research of po1yethylene, grafted with maleic anhydride asthe hot melt adhesive of the aluminumT1astics...