The effectiveness of a watersoluble synthetic acrylic polymer in enhancing reinforcing action of silica in carboxylated acrylonitrile butadiene rubber latex

Carboxylated acrylonitrile butadiene rubber (XNBR) latex was filled with surface modified precipitated silica. Surface modification of silica was affected in an aqueous medium by reacting with a synthetic polymer (SP) containing both hydrophilic and hydrophobic groups. The effectiveness of SP in enhancing reinforcing action of silica in XNBR latex films was evaluated through investigation of mechanical properties of vulcanized latex films cast from XNBR latex compounds filled with modified silica over a range of 5 to 20 phr loadings. Tear strength, which is an important mechanical property in certain latex based products like gloves, of modified silica filled cast films was found to be improved in comparison with that of unmodified silica filled cast films. Tear properties of cast films were continued to increase within the range of filler loadings investigated. An optimization of tensile strength was observed at 15phr filler loading in films containing modified fillers and it exceeds the tensile strength of unmodified filler added films with same loading. Morphological studies performed by scanning electron microscopy illustrated that a better distribution of modified filler particles within the XNBR matrix has occurred which may be a consequence of the discouragement of filler aggregation with surface modification. Surface modification of silica has improved the reinforcement action on XNBR.