Effects of Maleic Anhydride Content on Thermomechanical and Mechanical Properties of Maleated Natural Rubber

Influences of maleic anhydride (MA) contents (1-10 wt%) on the properties of natural rubber (NR) grafted with MA – or maleated natural rubber (MNR) – were investigated. According to rheometric tests, the scorch and cure times of MNRs were longer than that of NR, because the acidity of MA slowed down crosslinking reactions and decreased grafting efficiency of MA onto the NR. The maximum torque and torque difference of MNRs were improved over NR due to the maleated linkages formation. These maleated linkages induced greater crosslink density and shifted thermo-stability of NR toward higher temperature. A dramatic increase in crosslink density was attained in the MNR containing 1% MA, having also the highest thermomechanical properties and tensile strength. The thermostability and tensile strength of the MNR containing 1% MA were improved by about 10 ℃ and 53% over those of the NR.