| This paper adopt the new processing technology, the microbiological coagulation and airing.We make the five strains NR (RRIM600,PRI107,73397,72059,879),six months NR of RRIM600 (May to October) and vulcanized rubber. Then we compare the different strain NR latex rubber particle size, dry rubber content, six basic indexes of raw rubber (P0, PRI, volatile matter content, nitrogen content, impurity content, ash content), molecular weight and its distribution, the metal ion content, crosslinking density, mechanical properties, ozone aging performance. We adopt infrared functional calculation method to characterize the five strains of ozone aging performance discrepancy. We also adopt the vulcanization dynamics calculation method to characterize the discrepancy of the five strains in vulcanization dynamics. Activation energy for the new process of three stages is put forward to select suitable strain on the basis of it. These provide theoretical basis for high performance natural rubber process; We Also compares the RRIM600 molecular weight distribution of the production in six months, six basic indexes, metal ion content, mechanical property and ozone aging performance, at the same time ways is obtained by using the infrared characterization function of molecular structure of natural rubber in different raw rubber. DMA and RPA under the condition of the new technology test the dynamic mechanical properties and processing properties of vulcanized rubber. Natural rubber in different resistance to ozone aging was analyzed. These provide theoretical basis and the production time for high performance natural rubber process. Thesis research results show that:(1) strain from five strainsFresh latex particle size distribution is widest in RRIM600 strains, a fairly large particle size (2500-7500) nm. Dry rubber content of RRIM600 is 0.38,but 73397 is minimum for 0.29; Adopting the new processing technology, molecular weight is 597000 and molecular distribution coefficient is 3.09 for RRIM600;however,72059 is 438000 and the molecular weight distribution coefficient is 2.183; 72059 total metal ion content is highest. Manganese and copper content accordingly is highest. The lowest ash content and low impurities content, moderate protein content, low volatile matter content come from RRIM600Rubber components. Ash content of 72059is the highest; the nitrogen content is low in it. High impurity content comes from 72059; DSC test found that RRJM600 have low glass transition temperature, and 72059 are in the top.Representation way is obtained by using the infrared spectra to calculate the molecular structure of natural rubber of functional groups before and after ozone aging. Results indicate that RRIM600 compared with other strains have lower branched chain structure, contain more 3,4, structure.After the reaction of ozone branched structure increase less than other strains, and 3,4 structure reduce a lot.RRIM600 mechanics performance and ozone aging resistance properties is higher than the other four strains. The mechanical strength is 30.21 MPa, When reached 20%, setting temperature 45 癈, humidity is 65%, ozone concentration 100 x 10-8, the ozone aging rate was 34%. The cracking time of RRIM600 is longest for 925 min.72059 ozone aging rate is 44.9%; the cracking time is the shortest for 810 min.Through vulcanization dynamics calculation, we found that at the end stage of curing kinetics five strains vulcanizing activation energy is different and it have different aging performance. RRIM600 vulcanizing activation is 114.65 KJ, showing strong chemical bonds. It is not easy to break. Crosslinking density showed RRIM600 crosslinking density is highest,12.20 x 10-5.(2) NR from RRIM600 in MonthsStudies have shown that the different molecular weight and its distribution of production in six month from RRIM600 are very big. The molecular weight is 590000 in October or more in May. Ash content is lowest. Impurities content is lower. The nitrogen content is highest in October. Mechanical performance is more than 30 MPa. The best ozone aging property and ozone aging rate is 34%. The cracking time is 930 minutes. Infrared structure calculation indicates that A strain molecular structure discrepancy in different month is not big, so the main factors that influence the ozone aging properties is the molecular weight, its distribution and the non-rubber components. It can be seen from the RPA and DMA analysis that high elastic modulus, low loss factor, low glass transition temperature, good crosslinking structure in September and October, Therefore, make high tensile strength, good crystallinity, molecular chain arrangement closely. Ozone aging at attacking double bond decreased, good aging resistance improved. TG curve of A strain at higher temperature in October and September after ozone aging, shows good resistance to ozone aging performance compared with others... |
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