Studies On The Grafting Modification Polyolefin Thermoplastic Elastomer By Reactive Extrusion And Its Application

In this paper,a long chain branched polyolefin thermoplastic elastomer was successfully prepared by reactive extrusion method.The effects of monomers,initiators and grafting conditions on the molecular structure,rheological property and thermal stability of the modified polyolefin thermoplastic elastomer were investigated.The modification of polyolefin thermoplastic elastomer was applied to toughen the waste plastics,which was of great economic value.This experiment used styrene monomer and POE to produce grafted polyolefin thermoplastic elastomer,investigating the content of monomer concentration,initiator,screw rotation speed and processing temperature on the molecular structure of modified polyolefin thermoplastic elastomer,rheological property,thermal stability and the grafting ratio.Results showed that these factors on the modification of the grafting rate and utilization rate of grafting monomers had certain effect,within a certain range were all conducive to increase the graft degree,up to 7.81%.But if the monomer concentration was too high would cause homopolymerize reaction,the initiator content was too much can cause crosslink reaction,the high process temperature can lead to monomer volatilization,the screw rotation speed was quick would intensify the degradation,these went against the increase of grafting rate.Through the analysis of the rheological test found monomer concentration and initiator content on the molecular chain of long branches structure had a certain influence,the change of processing temperature and screw speed had little impact on it.The blends of functional polyolefin thermoplastic elastomer(POE-g-St),pure polyolefin thermoplastic elastomer(POE)and waste polystyrene(rPS)were tested.By the mechanical property test,we found that the effect of ternary blends on toughening the waste polystyrene was better than that of binary blends.Moreover,when the mass ratio of rPS: POE-g-St: POE = 70:15:15,the impact strength of waste polystyrene was 2 times.And these results can be verified by the improved phase interface tension,contact Angle calculation,SEM analysis to interface compatibility,and rheological analysis of Cole-Cloe figure which can reflect the phase separation structure and homogeneous degree,Han curve analysis was further proved that.At the same time,the results of POE-g-St samples with different graft ratio were applied to the blends and the effect of toughening was not significant.On the base of experiments on POE-g-St toughening rPS,the POE-g-St,POE were applied in the compounding toughening modification of recycled ABS(rABS).Test results showed that only POE added can cause a decline in the impact of the rABS,but when the mass ratio rABS: POE-g-St: POE = 80:15:5,the impact strength of blend can be improved to 1.5 times than that of recycled ABS.By rheology data,contact Angle and SEM test,the situation can be further elaborated that the POE-g-St can improve the impact property of recycled ABS.When using different grafting rate of POE-g-St samples,it can be found that high grafting rate resulted in the crosslink structure which would be bad for toughening modification of ABS.