| Chlorinated polyethylene (CM) and Chloroprene rubber (CR) have similarsolubility parameter and polarity, and both rubbers contain chlorine atoms in theirbackbone chain, thus they have good compatibility in theory. In this paper, a series ofresearch focused on CM/CR blends has been investigated and the main purpose is togiveguidancetotheapplicationinpractice.Firstly, the compatibilityand mechanical properties have been studied by varioustechniques, SEM analysis showed that there was no obvious phase separationphenomenon,whichindicatedgoodcompatibility. IRspectrarevealedthereweresomechanges either in the position or the strength of absorption peak, so we believed theremust be some interaction between the two component rubbers. The glass temperatures(Tgs)ofcompounds weredeterminedbyDSC. It was foundthat thereweretwoTgs inthe blends with different blending ratios, which lied between the Tgs of the two purerubbers. And this result gave another evidence that the two rubbers are partiallycompatible.Composite vulcanization systems were applied in CM/CR blends. Mooneyviscosity increased while the mechanical property declined with the increase of CMcontent.Thermal aging propertyand oil resistance were improved with the addition ofCM. TG analysis showed that the degradation of CM presented two-step form, whileCR decomposition was mainly concentrated at the region about 320℃. The initialdegradation temperature was lowered slightly, while the degradation rate was heavilyreduced at low temperature region with the addition of CM,thus the thermal aging propertywasimproved.Secondly, with the consideration of difference in curing system between the tworubbers, we applied TCHC,NA-22/S,TDD/NC,TCY and 3 peroxide systemscompounded with metal oxide respectively. The results showed CM/CR blends couldbe cured with the above curing systems we have chosen. The vulcanizate cured byTCHC system possessed better mechanical property and oil resistance. And thecrosslink density determined by equilibrium swelling method was the highest amongall thevulcanizates. It was foundthat bothCM andCR couldbecuredbyTCHC.5phrTCHC as curing agent was favorable for comprehensive performance of CM/CRblends. Rubber Computer Aid Design system (RCAD) was applied to investigate theeffect of metal oxide on the properties of blends. The results showed that ZnO couldaccelerate the dehydrochlorination which would likely cause bubbles on thevulcanizate surface. So ZnO was suggested not to be added in the blends. MgO actedas acid absorbent and stabilizer in the curing process, the recommendatory dosage ofMgOwas8phr.Finally, filling system has been studied, the results showed that all CM/CRcompounds filled with different kinds or loadings carbon black exhibited Payne effect.The more loading and the smaller carbon black particle size in compound, the moreobvious Payne effect appeared indicating the worse dispersing and processingperformance; however small particle size was favorable for reinforcement. The carbonblack with large particle size would lead to the prolongation of cure time. The blendfilled with N550 in the amount of 30 phr had better reinforcement performancecompared with other kinds of carbon black. When the blend was filled with carbonblack/silica, the amount of fillers was set at the same level (60 phr). With the increaseof silica amount, both scorch time and cure time were prolonged and the mechanicalproperty declined. All the blends possessed good aging property. The blend had thebest oil resistance when the silica content was 10 phr. The most obvious Payne effectwas observed in the compound filled with onlycarbon black. 10 phr silica substitutionforcarbon black facilitatedthe dispersingproperty, and then with the more addition ofsilica,thePayneeffectwasimprovedrelatively. |
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