| Chlorinated polyethylene (CM) is favored increasingly by people because ofhaving good resistance to aging and oil, fire retardant and low cost of produce. CM isusually vulcanizated by peroxide system, vulcanizing assistants have a rather big effecton the cross-linking workpiece ratio and mechanical properties of CM vulcanizates, onwhich the blowing characteristics are based of CM are studied, it will have importantpractical sense if CM sponge could replace other general sponge rubbers.The effects of N,N'-m-phenylene-d-maleimide(PDM)and trithiocyanuric acid(TCY) onthe curing characteristics of CM compounds and the properties such as mechanicalproperties, thermal oxidization and oil resistance of CM vulcanizates were investigated.The basic properties of foaming agents such as decomposition temperature and particlesize were characterized by differential scanning calorimeter (DSC), thermal gravimetry(TG) laser granulemotry. The effects of different factors such as Mooney viscosity ofCM, filler content and kinds of foaming coagents etc. on the foaming properties of CMvulcanizates were also studied. The experimental results showed that the optimumcuring time of CM compound using TAIC was shorter and the cross-linking degreewas higher, PDM was the second. The curing apparent activation energy of TAIC waslowest(78.9KJ/mol), the second one was TDD+NC,PDM, and TCY was thehighest(102.65 KJ/mol). The change rates of tensile strength, mass and capacity of CMvulcanizates with PDM were lower, the tensile strength was remarkable (+6 and -3). Inthe condition of hot oil aging (100℃×72h), the oil resistance of CM vulcanizates withTAIC was better. CM vulcanizates with PDM adding talcum powder had better thermaloxidative aging resistance, and had less change rate of mass and capacity in 1~# and 3~#standard oil. The compression set of CM vulcanizates with TAIC and PDM was lower.The decomposition course of organic blowing agent was exothermal reaction according to the DSC curves of blowing agents. Blowing agent HH130 and ACP-Whave lower decomposing temperature, which is about 125℃. Meanwhile theexothermal peak is wider and the exothermal amount is bigger. The decomposingtemperature of blowing agents HH180, HH808B, OBSH, MC1, LC2, FC2 and SC2was higher and the exothermal peaks were sharper. The decomposing temperature ofSC2, FC2, MC1and LC2 is 215℃and the average particle size ofMC1, LC2 and SC2was smaller than that of FC2 (24.45μm) according to the curves of capacity (mass)cumulative distribution. In the particle size dimension studied, the effect of particlesize on blowing characteristics is minor. Better blowing appearance and characteristicscould be obtained when the content of SC2, FC2, MC1 and LC2 was 8phr. Activeagent ZnO which made the decomposing temperature decrease 50℃had strongeractive effect than blowing agent FC2, zinc stearate and carbamide are the second,otherwise the stearic acid almost has no active effect blowing agent FC2. The contentof filler had bigger effects to blowing appearance and mechanical properties and it wasbetter that the content is 30phr. It can be gained blowing samples which have goodblowing appearance and lower density when using vulcanizing assistant TAIC, thepacking compact was 33g and the blowing pressure was 10MPa. The hardness anddensity of CM vulcanizates became bigger with the pressure increasing. The CMvulcanizates was softer and the hardness and density was becoming smaller with thecontent increasing of DOP. Good blowing appearance and smaller density sampleswhich density was 0.149g/cm~3 could be gained by using epoxidized soybean oil as thesoftening agent. |
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