Study On Flame Retardant Chlorosulfonated Polyethylene Rubber Foams

In this paper, the chlorosulfonated polyethylene rubber (CSM) was used as basic materials, the effect of vulcanizing systems, foaming agent, post-processing technology, synergistic foaming agent and synergistic flame retardant on curing properties, foaming properties, shrinking percentage and flame retardant properties of CSM foams were systematically studied by Shock disc rheometer (FFR), open-closed porosity analyzer, scanning electron microscopy (SEM), limit oxygen index (LOI) tester and thermo-gravimetric analyzer (TGA). The CSM materials with the properties of light-weight and flame-retardance were prepared. The results show that:The curing speed of MgO/PER/S curing system was fastest, the comprehensive mechanical properties of CSM foams were best; meanwhile this curing system did not produce carcinogenic nitrosamines and malodorous acetophenone. So this curing system is environmentally friendly.Foam research results showed that, in CSM compounds, AC blowing agent played the role of delaying but not preventing vulcanization reaction. When the amount of AC blowing agents was greater than 8 phr, the blowing rate of CSM rubber was accelerated; when greater than 10 phr, the density reduce of CSM materials slowed down. The CSM foams with both open and closed structure were formed after synergistic foaming agent NaHCO3 added. The compression stress-strain curves of these foams had the typical characteristics of elastomer foam materials. On the premise that the foam structure is not bursted by gas, to improve the open cell percentage, the effective dosage of NaHCO3 is 12phr.The post-processing technology effectively reduced the shrinkage of CSM foams and increased the mechanical properties to some extent. The best post-processing condition was 80℃,3-4h was drawn out by fixed the post-processing time and temperature respectively.Flame retardant results showed that, the vertical combustion level of CSM foams can reach V-0 level; after adding 30 phr DBDPE and 25 phr synergistic flame retardant ZB2335, the LOI value of CSM foamds increased to 37.7%, tensile strength reached to 2.5MPa, and elongation at break reached to 241%. Thermal gravimetric analysis results showed that:after adding flame retardents, the maximum weight loss rate reduced and flame-retardant effect improved.