Dielectric Properties Of Polystyrene Graft Copolymer/Low Density Polyethylene

Study found that adding compound containing benzene ring structure can effectively improve the cross-linking polyethylene(XLPE)short-term electric strength and the starting voltage of electric branches,the appropriate additive can effectively improve the performance of polyethylene,it is a kind of method to improve insulation performance for polyethylene over a long period of time.This paper was based on the current research status of polyethylene,by electron irradiation and emulsion polymerization,the polystyrene molecule is grafted onto polyethylene chain,and the PS-g-LDPE/LDPE composite material of different components is prepared.The mechanical and electrical properties such as DMA and DSC were studied.The DSC test show that the degree of crystallinity of LDPE with LDPE-g-PS improve 10%.Dynamic mechanics analysis test and tensile test results show that storage modulus of composite materials increased from 40 MPa to 70 MPa under 85?,at room temperature the elongation at break and yield stress has improved,through melt blending method polystyrene graft copolymer can be compared with LDPE uniform fuses in together,though changed the LDPE molecular chain structure of the original,but the PS has good dispersancy.AC breakdown experiments show that polystyrene graft copolymer can effectively improve the breakdown strength of composite material at 80°C to 90°C,compare to low density polyethylene by about 20%.The analysis suggests that it may be that the increase of crystallinity increases the rigidity of the system and increases the ability to resist electrical damage.It may also be that the introduction of the benzene ring which can absorb high-energy electrons makes the electrons more likely to be captured without producing an electron collapse.It was found that polystyrene existed in the form of nano-spheres in low density polyethylene matrix.The conductivity test indicates.Conductivity tests show that adding the polystyrene graft copolymer of the conductivity of the composite conductivity two orders of magnitude lower than LDPE,may be due to the addition of styrene groups can inhibit the conductance.TSC experiment shows that the spectrum peak of composites with polystyrene graft copolymer is moved to high temperature,with the addition of polystyrene graft copolymer,there form a clear new spectrum peak at 80?to100?,perhaps because with the introduction of benzodiazepines material can effectively improve the trap depth of LDPE.After the graft copolymer of polystyrene was doped with LDPE,the inhibition of space charge was significantly improved.