Enzymatic approach in accelerating colloidal stability of concentrated natural rubber latex and its effect on rubber products

In this work, enzymatic treatment was thoroughly investigated as an environmentally benign method for accelerating the colloidal stability and maturation rate of concentrated natural rubber latex (CNRL). It was found that the treatment of CNRL with lipase, an enzyme that catalyze the hydrolysis of lipids and phospholipids, was much more effective in boosting the colloidal stability of CNRL than the use of commercial ammonium laurate soap without causing an over-stabilized problem at longer time. The investigation of lipase treatment in CNRL obtained from different production lots indicated that the lipid content in CNRL was the key parameter in determining maturation rate of lipase-treated latex: the latex lot with higher lipid content could be maturated faster. Moreover, lipase treatment could also reduce the use of ammonia by at least 50% (from 0.6 to 0.7 to less than 0.29 wt%) and could completely replace the use of zinc oxide and tetramethylthiuram disulfide (TMTD), a carcinogenic chemical commonly used in low-ammonia latex, without affecting its colloidal stability. For the effect on the downstream processes, it was found that lipase treatment did not cause any adverse effect to downstream product-forming process but could also lead to stronger cross-linking bonds and better rubber product quality.

Automated summary

This research discovered that enzymatic treatment can enhance the colloidal stability of concentrated natural rubber latex while reducing the use of chemicals and improving the quality of rubber products.