Study On The Detection Of Adulterated Fresh Natural Rubber Latex And Its Effect On The Properties Of Rubber

In recent years, Driven by the economic benefits, some dishonest farmers mixed something which is not rubber material in the natural fresh rubber latex to improve the concentration and gain more economic benefits. After natural rubber fresh latex adulterated with the non rubber material,the property of natural fresh rubber latex、 physical and chemical properties of the raw rubber would be changed,which not only influenced quality of natural rubber,but also damaged benefit of the rubber processing factory.. It is difficult for us to distinguish the natural fresh rubber latex adulterated with nonrubber material with the naked eye. We must quickly detect adulterated substances which is in the natural fresh rubber latex to protect the interests of the glue factory and improve the quality of natural rubber. So far, there is rarely reported about research of fresh latex adulteration not only domestic but also foreign.This article detected several common adulterated substances in fresh natural rubber latex including starch, sodium bicarbonate, sodium chloride, gelatin, and establish a set of simple and rapid method. This article also investigated the property of natural fresh rubber latex、physical and chemical properties of the raw rubber、vulcanization characteristics of blended rubber、mechanical properties and thermal stability of vulcanizates. Experimental results show that we can detected the incorporation of several substances in fresh latex with the chemical method. For example, the potassium iodide can be used to detect the starch, calcium chloride can be used to detect the sodium bicarbonate, silver nitrate can be used to detect the sodium chloride, potassium dichromate can be used to detect the gelatin, primer can be detected by centrifugation after the latex color. After the natural rubber fresh latex adulterated with starch、gelatin、primer,the viscosity improved, Especially, the viscosity of gelatin Increased by 1020%. Ammonia content and conductivity improve significantly after the natural rubber fresh latex adulterated with sodium bicarbonate, the density and conductivity increased significantly, after the natural rubber fresh latex adulterated with sodium chloride. Impurity content, ash content, nitrogen content, volatile matter content of raw rubber all improve when the natural fresh rubber latex mined with starch, sodium bicarbonate, sodium chloride, gelatin and primer, but the plastic initial value and plastic retention rate reduced, the torque of rubber vulcanizate declined, curing time extend, the mechanical properties of vulcanizate decreased, thermal stability degraded.