Study Of PP/UHMWPE/Graphene Blends

Polypropylene(PP)is one of the fastest developing resins in recent years.Because of its easy processing,excellent mechanical properties,stable chemical properties and corrosion resistance,PP is widely used in various industries.However,single-component PP has been difficult to meet the requirements of multifunctional and high-performance materials.In order to make PP material suitable for more occasions,it is usually necessary to modify PP in different ways,so as to add properties that PP does not have,and achieve the purpose of expanding its application range.The modification methods of PP mainly include physical modification and chemical modification,among which blending modification in physical modification is a simple and obvious method to improve the mechanical properties of PP.Ultra-high molecular weight polyethylene(UHMWPE)is blended with PP in the experiment,mainly considering the excellent comprehensive properties of UHMWPE,which has unparalleled impact properties and wear resistance.The most important thing is that UHMWPE can still maintain good mechanical properties at low temperature,which can just make up the defects of PP and improve the properties of PP.However,UHMWPE has extremely high molecular weight,and its molecular chains are intertwined,resulting in poor processability.It is very difficult to mix with PP evenly,which will be the first problem to be solved in this experiment.In this experiment,in order to solve this problem,UHMWPE master batch was made first.In addition,a small amount of TPO was innovatively added into UHMWPE master batch.TPO is a polyolefin thermoplastic elastomer with solution viscosity between PP and UHMWPE,which is conducive to the uniform dispersion of UHMWPE and PP.In this paper,the effects of UHMWPE and PP blends on tensile strength and crystallization properties were studied,and then different proportions of graphene were added into the blends to explore the effects of graphene on the molding shrinkage,ultraviolet resistance and tensile strength of PP/UHMWPE blends.The final conclusions of this paper are as follows:(1)The addition of TPO improves the compatibility between UHMWPE and PP to a certain extent,but it can not completely eliminate the harm caused by the incompatibility between UHMWPE and PP,and the tensile strength of PP/UHMWPE blends decreases slightly with the increase of UHMWPE content.(2)The tensile strength of newly formed PP/UHMWPE blends is not enhanced compared with pure PP,but with the extension of the standing time at room temperature,The tensile strength of the blends is rising continuously,and the reinforcing effect of UHMWPE on PP is gradually emerging,among which the composite with 10% UHMWPE masterbatch has the best reinforcing effect.This accords with the characteristics of secondary crystallization of materials,which indicates that the enhancement of UHMWPE to PP is realized by the secondary crystallization of UHMWPE.(3)Graphene has a good reinforcement effect on PP/UHMWPE blends when the addition of graphene is below 9%.However,after the addition ratio of graphene exceeds 9%,graphene is easy to agglomerate,which brings negative influence to PP/UHMWPE blends,and the tensile strength and elongation at break of the blends begin to decrease.(4)Graphene can greatly improve the anti-ultraviolet ability of PP/UHMWPE blends.When the amount of graphene is between 6% and 12%,PP/UHMWPE/Graphene blends still maintain good tensile strength after long-term ultraviolet irradiation.(5)The electrical conductivity of PP/UHMWPE/Graphene blend material was not enhanced by melt blending graphene with PP/UHMWPE crushed material by extruder.When the addition of graphene was 12%,the surface resistance is only reduced by one order of magnitude.(6)The addition of graphene can improve the shrinkage of PP/UHMWPE blends.When 12% graphene is added,the shrinkage of PP/UHMWPE/Graphene blends decreases from 1.04% to 0.3%.(7)With the addition of a small amount of graphene,the original materials are extremely resistant to microwaves The heating rate of PP/UHMWPE/ Graphene blends with12% graphene under microwave is more than 6 times that of PP/UHMWPE blends.The new application of graphene in improving microwave heating of materials was explored.