| Choose the conditions of vulcanization system as follows:2phrDCP,2phrS, 5phr ZnO. The NR modified by four kinds of methacrylic acid salt including ZDMA, MDMA, NaMA and KMA were prepared, the mechanical properties of modified NR vulcanizates were investigated. The results showed that with the increasing of ZDMA and MDMA, the swelling degree of NR vulcanizates were obviously decreased which means that the crosslinking degree of NR vulcanizates were obviously increased.In the presence of both sulfur and dicumyl peroxide (S/DCP) as a curing agent, the research do the single factor experiment at first. Including the dosage of DCP, S and zinc oxide(ZnO), they have effect on the vulcanizing properties of modified NR and the vulcanized properties of modified NR. The optimal technical conditions of vulcanized NR were as follows:the DCP contents was 1.5～2.5phr, the S contents was 2～3phr, the ZnO contents was 5～7 phr.The mechanical properties of vulcanized NR modified by ZDMA were obviously increased. When the ZDMA contents was 10phr, the vulcanized NR got the best mechanical properties. The mechanical properties of vulcanized NR modified by MDMA were obviously increased. When the MDMA contents was 10～15phr, the vulcanized NR got the best mechanical properties. Vulcanized NR modified by MDMA, NaMA and KMA could keep very good mechanical properties after the hot-air ageing(100℃×24h), which vulcanized NR modified by ZDMA couldn'tthe NR modified by ZDMA with calcium carbonate (ZDMA/CaCO3) and the NR modified by CaCO3 were prepared, the mechanical properties of modified NR vulcanizates were investigated. The results showed that the NR vulcanizates modified by ZDMA/CaCO3 could improve properties great and got higher strength, higher modulus than NR vulcanizates modified by CaCO3. The best contents of ZDMA/CaCO3 was 10/10, that the tensile strength increased 29.52% and tear strength increased 36.70%. That showed that ZDMA can improve the combination of CaCO3 with NR and the dispersion of CaCO3 in NR. |
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