Preparation And Properties Of Radiation Cross-Linked Rigid PVC/Epoxy Resin Foaming Materials

Although the mechanical properties and heat resistance of rigid cross-linked PVC(R-PVC)foaming materials prepared by radiation cross-linking modification method are not as good as those prepared by chemical cross-linked modification,radiation cross-linked PVC foaming materials have gotten much attention because of its advantages,such as small cells,low water absorption,low material cost,high production efficiency,energy saving and environmental protection.With the purpose of improving the mechanical properties and heat resistance of the radiation cross-linked rigid PVC foaming materials,this paper used methacrylic sensitizer as cross-linker to prepare radiation cross-linked rigid PVC foaming materials,and introduced bisphenol A epoxy resin as the second cross-linked network structure.This work is not only of great significance to expand the application field of R-PVC foaming materials and realize energy saving and environmental protection production technology,but also has scientific research value,the results are as follows:(1)Among the selected four sensitizers,R-PVC foaming materials prepared by three functional groups sensitizer 1 had the best mechanical and heat resistance.When the concentration of foming agent was 10 phr and the concentration of sensitizer 1 was 10 phr,the mechanical and heat resistance of the R-PVC foaming materials were the best,but when the concentration of sensitizer was greater than 10 phr,R-PVC could not foam normally.When the concentration of sensitizer 1 was 8 phr and the concentration of foaming agent was 8 phr,the mechanical and heat resistance of the R-PVC foaming materials were the best When the concentration of foaming agent was less than 8phr,R-PVC could not foam normally.(2)A series of R-PVC/EX foaming materials were prepared by using two bisphenol A epoxy resins(EX)with an epoxy value of 0.05 and 0.12 companied with dicyandiamide and modified diaminodiphenyl sulfone(DDS)as curing agents.With the increasing of concentration of EX,the gel content,foam density,compression strength,compression modulus and the Martin heat resistance temperature of R-PVC/EX foaming materials all showed a trend of increasing at first and then decreasing.Using dicyandiamide as curing system,the optimal concentration of EX was 8phr,and R-PVC/EX(dicyandiamide curing)foaming materials with an epoxy value of 0.05 had better properties.Using modified DDS two-stage as curing system,the optimal concentration of EX was 10 phr,and the properties of R-PVC/EX(DDS curing)foaming materials with an epoxy value of 0.05 were better and even better than that of R-PVC/EX with dicyandiamide curing system.(3)Using the two-stage curing characteristic of modified DDS curing agent,a series of R-PVC/EX-DDS foaming materials were prepared with EX-DDS that was pre-cured product of epoxy resin(EX)with an epoxy value of 0.05 and modified DDS.With the increasing of concentration of EX-DDS,the gel content,foam density,compression strength,compression modulus and the Martin heat resistance temperature of R-PVC/EX-DDS foaming materials all showed a trend of increasing at first and then decreasing.When the concentration of EX-DDS was 12 phr,R-PVC/EX-DDS foaming materials had the best performance and even better than that of R-PVC/EX with DDS curing system.(4)Under the condition of 12 phr for EX-DDS and 10 phr for foaming agent,the mechanical and heat resistance of R-PVC/EX-DDS foaming materials were the best properties even better than that of R-PVC without EX,when the concentration of sensitizer 1 was 9phr.Under the condition of 12 phr for EX-DDS and 8phr for sensitizer 1,the mechanical and heat resistance of R-PVC/EX-DDS foaming materials were the best properties even better than that of R-PVC without EX,when the concentration of foaming agent was was 9phr.