Study On Structure And Properties Of Natural Rubber Collected In Different Seasons

Two strains (reyan7-33-97and reyan8-79) rubber tree which was opened cutting four years were researched, the rubber latex was collected from the rubber trees which were cut two times every week, Comparing those of the raw rubber collected (from May to December), particle size, total solids content,content of dry rubber,nitrogen content,ash content, impurity content,volatile matter content,acetone conten,Po,PRI,Mooney viscosity, molecular weight and its distribution,processing performance,mechanical properties and aging properties, thermal stability of rubber were studied. It will provide important theoretical basis for the production of natural rubber.The experimental results show that the strain7-33-97in different natural rubber latex particles in the rubber in November the particle size is the largest,and this month least than suface area of the minimum;Strain8-79is also the November average particle size is the largest,surface area least than the minimum, the biggest particle size of two strains were40μ m,32.03μ m.The strain7-33-97and8-79strains of natural rubber latex from started in May after the cutting open, all is August total solid content and dry glue the highest levels of the dry rubber content in December minimum;Strain7-33-97in the July issue of the nitrogen content minimum,volatile content is the highest, the ash content in December and impurities in the lowest in August, the highest content of acetone insoluble substance in August, the initial value of plastic Po is the largest, the highest PRI in November that its raw rubber oxidation resistance best, in August, the highest mooney viscosity, the Mn in May, Mw和Mz are the largest, the December issue of Mn, May, Mw are the smallest, but its molecular weight distribution width index is the biggest of all.Strain of8-79in August, the content of nitrogen is the highest, and also the mooney viscosity, the highest content of impurities is in October,and also the ontent of acetone, the Mn, Mw are the largest;the issue of initial value Po and plastic Mooney viscosity are the largest in July, the highest of PRI is in October;in May, the Mn, May, Mw are the smallest, and the molecular weight distribition width index is the largest.In strain7-33-97, the initial modulus of elassticity in July are significantly higher than in other months, as the strains increases, the modulus of elasticity is becoming more and more similar, and the beginning of internal fricition is very low, but as the strain increases, the internal fricition increases significantly, other natural rubber internal fricition rising gently; In strain8-79, June, August to December, the critical shift, in May and July, but abnormal, After critical the whole site, the elasticity of the whole site with increasing contingency and reduce internal fricition increases.Strain7-33-97in August, the tensile strength and tear strength are higher than other months, and in July, the mechanical properties is the worst; strain8-79, the issue of the tensile strengh and tear strength is the largest in July, the mechanical properties of the worst is in Sepember.In strain7-33-97, the initial temperature degradation in May is the biggest, and the decomposition rate is the lowst temperature, and the two highest temperture is Septemper, the heat stability in Semperber is the best; In strain8-79, initial temperature and maximum degradation are the lowest, and also the rate of degradation is the lowest temperature, In October, the two temperature are the highest, and the heat stability is the best.