Pretreatment of Hevea Latex by Sorbitol: Improving the Efficacy of Silica Dispersion by a Biomimetic Approach

Incorporating a high amount of silica in cis-1,4-polyisoprene (CPI) by conventional dry mixing is a Herculean task. A biomimicking approach is adopted herein through incorporation of a bio-based sugar alcohol (sorbitol) into the CPI latex, which creates protein-carbohydrate interactions in the latex called protein-sugar conjugates. These treatments unveiled a significant improvement in key properties of the CPI vulcanizates, like >15% reduction in tan delta at a high temperature, besides better dispersion as evident from morphological studies. The protein and phospholipid ends were cleaved by respective enzymes for a clearer percipience of their individual effects on compounds' key properties. The molecular dynamics study reveals a faster convergence of root-mean-square deviation (RMSD) and maximum radius of gyration (R-g) values of the sorbitol-treated latex, confirming a stable conformation of the CPI matrix in the presence of silica. Subsequently, a greater number of hydrogen bonds between the functional groups of protein and sorbitol demonstrates successful blocking of the functional groups (protein-sugar conjugates) of CPIs' unwanted substances.

Automated summary

Incorporating a bio-based sugar alcohol into CPI latex through protein-sugar conjugates shows significant improvement in key properties of CPI vulcanizates. Molecular dynamics study confirms stable conformation of the CPI matrix in the presence of silica, and successful blocking of unwanted substances' functional groups in CPI.