Preparation And Properties Of Polyolefin Elastomer Forming Materials

The polymer foaming materials have a lot of advantages,such as light weight,heat insulation,sound insulation,etc.Compared with the common use of thermoplastic polyurethane(TPU)and Ethylene Vinyl Acetate Copolymer(EVA)for foaming materials,POE foaming materials have the advantages of low price,wide source and direct contact with human body.At present,the domestic technology for the preparation of POE foaming materials mainly stays in chemical foaming,but it has some throwbacks such as environmentally unfriendly and the residual,of chemical foaming agent,which will affect the mechanical properties of the polymer.The research found out that for material A,the best foaming conditions are saturation pressure 13.8 MPa,-time 4 h,-temperature 35°C;for material B,the best foaming conditions are:saturation pressure 13.8 MPa,-time 4 h,-temperature 40°C;for material C,the best foaming conditions are saturation pressure 13.8 MPa,-time 4h,-temperature 40°C;For material D,the conditions for achieving optimum foaming conditions are saturation pressure 13.8 MPa,-time 2 h,-temperature 40°C.For the heat resistance of the four materials,the materials A&C showed signs of melting after undergoing an oven heat treatment of 130 mins at 60°C,while the materials B&D showed no major change when subjected to an oven heat treatment at 80 ~oC with the same duration.Due to the internal stress and the influence of the internal and external pressure difference of the gas,the four materials have a large shrinkage rate.After experiencing the natural rebound after foaming,the shrinkage rates of the four materials A,B,C,and D were 48%,49%,44%,and 41%,respectively.After testing the compressive properties of the four materials,it was found that material C has the best compression stability.The maximum compressive stress is 194 kPa and the energy loss is 14.2%at a strain of 10%.At a strain of 40%,the maximum compressive stress is 745 kPa,and the energy loss is 20.8%;at a strain of 50%,the maximum compressive stress is 1128 kPa,and the energy loss is 26.3%;when the strain is 75%,the maximum compressive stress is 6090 kPa and the energy loss is53.1%.After 100 cycles of compression,the maximum compressive stress did not change much,and the energy loss also decreased from 36.1%of the first cycle to26.3%and remained relatively constant.After the heat treatment,the maximum compressive stress and energy loss of the four materials showed an upward trend for the heat treatment fixed molecular chain.The material C with the best mechanical properties was selected,and the method of adding carbon nanotubes,low temperature treatment and adding CPE was adopted to improve the materials shrinkage rate.Adding carbon nanotubes does not improve its shrinkage performance,only enhances its mechanical properties.Since internal stress is dominant during shrinkage,low temperature treatment has little effect on shrinkage;after CPE is added,with a strong elasticity,the shrinkage rate of the polymer is accelerated and the compression properties are slightly reduced.