Study On The Grafting Of Polyolefin With IA By Reactive Extrusion

The compatibility between polyolefin and other materials can be improved viagrafting-modified polyolefin to introduce polar or functional lateral group. Theapplication realm of polyolefin can be extended in this way. On the basis of presentresearch results on the reactive extrusion of polyolefin both at home and abroad, Theauthor chose three typical reaction extruding systems, which are low densitypolyethylene (LDPE)/dicumyl peroxide (DCP)/itaconic acid (IA), linear low densitypolyethylene (LLDPE)/dicumyl peroxide (DCP)/ itaconic acid (IA), polypropylene(PP)/dicumyl peroxide (DCP)/itaconic acid (IA), as the research targets to study reactionextruding grafts in the twin screw extruder. The effects of initiator and monomerconcentrations, rotating velocity, styrene (St) co-monomer and addition agent N,N-dimethylformamide (DMF) were investigated and the graft products which hadbetter graft degree and MFR were gained. The graft structure and graft degree weredetermined and tested by IR spectra. On the basis of these studies, the effect of PPgraft product on mechanical properties of PP/CaCO₃ and PP/PA6 blend wereinvestigated and the interior structure of the blend was analyzed by SEM.On the study of LDPE-g-IA, The IR spectra showed IA was successfully graftedonto LDPE backbone.The graft degree rose and then dropped and MFR decreased allthe while with the increase in DCP content. The graft degree increased remarkably andthen decreased, but MFR decreased with the increase in IA content. The graft degreerose and then dropped with the increase in screw speed.When the screw speed was120r/min,the graft degree was the best. Styrene could improve graft degree remarkably.On the study of LLDPE-g-IA, The IR spectra showed IA was successfully grafted onto LLDPE backbone.The graft degree rose and then dropped and MFR decreased allthe while with the increase in DCP content. The graft degree increased remarkably andthen decreased, The MFR increased and then decreased with the increase in IA content.The graft degree rose and then dropped with the increase in screw speed. Styrene couldnot improve graft degree remarkably.On the study of PP-g-IA, the graft reaction was investigated by IR spectra. Thegraft degree increased with the increase in DCP content, and increased with theincrease in IA content. But the MFR decreased with the increase in IA content. Thescrew speed 96r/min was the best.DMF and St could restrain the degradation of PP, butcould not improve graft degree remarkably.On the study of PP/CaCO₃ blend compatilized by PP graft product, we found thatthe tensile strength, bending strength and notched impact strength all increasedremarkably.The high graft degree was not ideal.The effect of using PP-g-IA,PP-g-MAH and PP-g-GMA together as compatilizer of PP/CaCO₃ blend was not betterthan using solely each of them.On the study of PP/PA6 blend compatilized by PP graft product, we found that theeffect of using PP-g-IA or PP-g-MAH as compatilizer of PP/PA6 blend the tensilestrength, bending strength and notched impact strength all increased remarkably. Theeffect using PP-g-MAH as compatilizer of PP/PA6 blend was better than usingPP-g-IA, but the notched impact strength was not better. So the PP-g-IA can be used asthe compatibilizer and impact modifier for PP/PA6 blend.