不同采胶因素对天然橡胶性能的影响

The Influence of Different Latex Harvest Factors on the Properties of Natural Rubber

研究割龄、割频和化学刺激3种因素对天然橡胶鲜胶乳、生胶和浓缩胶乳性能以及胶乳橡胶粒子粒径大小与分布、生胶分子量大小与分布等因素的影响。结果表明:对天然橡胶品质影响最大的因素是割龄,其次是化学刺激和割频。割龄方面,4年割龄橡胶树胶乳总固体含量、干胶含量较高,橡胶粒子粒径、粒径分布系数较高,生胶重均分子量也较高;2年割龄橡胶所产生胶灰分含量较高,撕裂强度、拉伸强度和300%定伸应力较高,浓缩胶乳机械稳定度也较高。化学刺激方面,刺激割胶生产的橡胶塑性初值、门尼粘度和数均分子量较高;不刺激割胶生产的橡胶塑性保持率、氮含量较高,且浓缩胶乳机械稳定度也较高。割频方面,六天一刀割制所产鲜胶乳非橡胶固体含量、生胶门尼黏度和数均分子量、浓缩胶乳热稳定性均较高。

An attempt was made to study the effects of tapping age, tapping frequency and chemical stimulation on the properties of natural rubber latex, raw rubber and concentrated latex, the size and distribution of rubber particles, the molecular weight and distribution of raw rubber. The results showed that the most important factor affecting the quality of natural rubber is tapping age of rubber trees,followed by chemical stimulation and tapping frequency. In terms of tapping age, the fresh latex collected from the rubber trees tapped at the 4th year is higher in total solid content, dry rubber content,and size and distribution coefficient of rubber particle particles, and the raw rubber is also higher in weight-average molecular weight;the raw rubber derived from the latex of the rubber trees tapped at the 2 years is higher in ash content, tear strength, tensile strength and modulus 300%, and the concentrated latex is higher in mechanical stability. In terms of chemical stimulation, the raw rubber produced from the latex of rubber trees under stimulation is higher in initial plasticity value, Mooney viscosity and number-average molecular weight;the raw rubber from the latex collected from the rubber trees without stimulation is higher in plasticity retention index and nitrogen content, and the concentrated latex is higher in mechanical stability. In terms of tapping frequency, the fresh latex collected from the rubber trees tapped at the frequency of 6 days is higher in content of non-rubber solid components;the raw rubber is higher in Mooney viscosity and number-average molecular weight;the concentrated latex is higher in thermostability.