Preparation And Characterization Of High Performance PVC Composites

Polyvinyl chloride(PVC)is extensively applied in pipe materials,wires and cables and daily products due to its excellent comprehensive properties.However,both rigid PVC(RPVC)and soft PVC(SPVC)have some disadvantages in the use process:(1)long-time ultraviolet irradiation leads to the degradation of RPVC material performance.(2)SPVC is prone to burn and has a great potential safety hazard,which further limits the application of PVC materials.Based on the above problems,in this paper,BF2-TPE/RPVC blending films and BMC/SPVC composites were prepared with RPVC and SPVC as matrix,β-diketone boron complex(BF2-TPE)as light stabilizer,basic magnesium carbonate(BMC)as flame retardant and polyether titanate coupling agent(e Ti4000)as modification agent,respectively.The effects of BF2-TPE on the UV aging resistance of RPVC and BMC on the flame retardancy and smoke suppression of SPVC were investigated.The major research contents and results of this paper are listed as follows:Firstly,a series of BF2-TPE/RPVC blending films were prepared by solvent casting method,and then the ultraviolet accelerated aging experiment was carried out.The effects of UV irradiation time and BF2-TPE content on the UV aging resistance of RPVC were studied.The results show that BF2-TPE can absorb UV light in the wavelength range of 220-450 nm.During the whole process of UV irradiation,BF2-TPE can not only inhibit the photooxidation degradation of RPVC,but also enhances the thermal stability of the RPVC blending film.Secondly,a series of BMC/SPVC composites were prepared,the effect of BMC before and after modification on the flame retardant and smoke suppression properties of SPVC was studied.The results show that the interface compatibility between BMC and SPVC is improved by e Ti4000 modification,the flame retardant and smoke suppression performance,char forming ability,thermal stability and mechanical properties of e Ti4000-BMC/SPVC composites are better than that of BMC/SPVC composites.Among them,50-e Ti4000-BMC/SPVC composite has the best flame retardant and smoke suppression effect,the limiting oxygen index(LOI)is increased from 23.9% for SPVC to 28.0% for 50-e Ti4000-BMC/SPVC composite;and the peak heat release rate(PHRR),total heat release,peak smoke production rate(PSPR)and total smoke production are decreased from 343.10 k W/m2,94.50 MJ/m2,0.17 m2/s and 27.20 m2/kg for SPVC to 234.20 k W/m2,70.20 MJ/m2,0.02 m2/s and 2.30 m2/kg for e Ti4000-BMC/SPVC composite with 50 phr e Ti4000-BMC,respectively.Finally,a series of BMC/SPVC composites were prepared by melt blending method with slice BMC(s-BMC)and globular BMC(g-BMC)as flame retardant.The effect of BMC morphology on the flame retardant and smoke suppression properties of the composites was studied.The results show that the comprehensive properties of s-BMC/SPVC and e Ti4000-s-BMC/SPVC composites are better than those of g-BMC/SPVC and e Ti4000-g-BMC/SPVC composites due to the large specific surface area of s-BMC and e Ti4000-s-BMC.The LOI can reach 28.2% for e Ti4000-s-BMC/SPVC composite with 50 phr e Ti4000-s-BMC,the PHRR and PSPR are 177.8 k W/m2 and 0.077 m2/s,respectively,and the young’s modulus and yield strength are 83.5 MPa and 14.9 MPa,respectively.Compared with s-BMC/SPVC,g-BMC/SPVC or e Ti4000-g-BMC/SPVC composite with 50 phr BMC,the flame retardancy and smoke suppression performance and the mechanical properties are significantly improved.