Research Of Nano-metal Oxides Cured And Reinforced Chloroprene Rubber

Chloroprene rubber(CR)is self-reinforcing,has excellent mechanical properties,contains chlorine atoms and can be used in harsh environments.CR containing chlorine atoms requires the vulcanization system containing metal oxide to achieve the purpose of practical application.Metal oxide as filler of rubber has a variety of practical application,such as reinforcing rubber,improving rubber composite’s modulus,accelerating vulcanizing process and so on.Therefore,adding metal oxides to CR can not only achieve the purpose of vulcanization,but also achieve the practical effect of reinforcement.It is of great significance to study the influence of different metal oxides to the different qualities of CR composite,and whether adding other fillers will have adversely effects to the CR/metal oxide composites.Accordingly,Nano Composites(NC)were prepared.The following work is carried out in this paper:(1)Chloroprene rubber/nano metal Oxide nanocomposites(CR/Metal Oxide NC)were prepared by curing and reinforcing chloroprene rubber with nano zinc oxide and nano magnesia,respectively.Nano-magnesia and nano-zinc oxide can vulcanize chloroprene rubber when used alone.The cross-linked bond is conjugate diene structure.The rate of vulcanization of applying zinc oxide to vulcanize CR is about 50%higher than that of magnesia,so the activity of zinc oxide to vulcanize CR is higher than magnesia.The torque difference of CR/MgO NC is lower than that of CR/ZnO NC,and the crosslinking density is higher than that of CR/ZnO NC.The vulcanization curve of CR/MgO NC has not reached the flat stage,and the torque difference obtained from the vulcanization curve is inconsistent with the actual situation.The mechanical properties of MgO/CR NC are worse than those of CR/ZnO NC.The friction between filler and rubber will be increased with the small density of nano-magnesia,and the loss energy of CR/MgO NC is obviously higher than that of CR/ZnO NC.The results indicated that zinc oxide was superior than magnesia in curing and reinforcing chloroprene rubber.(2)Apply nano alumina and nano titania to vulcanize and reinforce chloroprene rubber,respectively.Nano alumina and nano titania can vulcanize CR when used alone.In terms of vulcanizing rate,the order of vulcanizing activity of nano metal oxide is obtained:zinc oxide>titania>alumina>magnesia.The cross-linking density comparison shows that the strengthening order of nano metal oxides is zinc oxide>magnesia>titania>alumina.The conclusion of torque difference is consistent with the vulcanization rate.The improvement of mechanical properties of chloroprene rubber by metal oxides was as follows:titania>alumina>zinc oxide>magnesia.The order of loss energy of chloroprene rubber composite filled metal oxide is magnesia>alumina>titania>zinc oxide.The results show that titania can promote the mechanical properties of CR composite better than other nano metal oxide,and zinc oxide has the best vulcanization effect when used as vulcanizing agent for CR.(3)Chloroprene rubber/Montmorillonite nano composite(CR/MMT NC)was prepared by gel compounding method,and a suitable phr(parts per hundred parts of rubber)of single nano-metal oxides were added into the nanocomposite as vulcanizing agent and reinforcing agent.In contrast,under the condition of MMT as filler,study the effect of applying different gel compounding technologies for the effect of different phr of different single nano metal oxides on CR/MMT NC.Under the common vulcanizing formula of metal oxides,MMT is better than OMMT in the dispersion degree of filling in chloroprene rubber and the improving the performance of CR composite,so MMT is used as the filler to add into chloroprene rubber.The vulcanizing characteristics showed that the vulcanizing activity of the four nano-metal oxides did not change under the filling of MMT.When nano metal oxides are compounded with MMT gel,the metal oxide coated by MMT in the gel reduce its own vulcanization activity,the composites’ torque difference of the torque curve and crosslinking density.Nano zinc oxide is compounded with MMT gel,and zinc oxide has vulcanized chloroprene rubber in the drying process,resulted in more defects in the composite material and poor performance of the composite.The mechanical properties of CR/MMT-8/Al2O3-30 NC can be improved by the coating of MMT and the low vulcanizing activity of alumina.Nano titania has little effect on the composite when it is filled with MMT.The compounding of nano metal oxide with MMT gel will improve dispersion and avoid agglomeration,and the filler network will interact more strongly with the rubber,which will increase the tensile stress under small strain and increase the loss energy.Because nano magnesia can absorb acid in the vulcanization process,the loss energy of the composites filled by nano magnesia made by the two technologies is almost the same.