Crosslinking of Epoxidized Natural Rubber with Terephthalic Acid: Effect of Terephthalic Acid and Cassava Starch

By : Sa-Ad Riyajan, Watcharin Khiatdet, Thanawadee Leejarkpai, Duangporn Riyapan

Page No: 145-158

Abstract
The objective of the present work was to study the vulcanization of epoxidized natural rubber (ENR) latex using terephthalic acid (TA) as a novel crosslinker. The influence of TA on the physical properties including the swelling behaviour, tensile strength and thermal stability of the cured ENR, which was compressed at 180o C for 30 minutes, was studied. The optimum mechanical properties were observed for particular ratios of ENR/TA. In addition, the effect of cassava starch (CSt) and glycerol on the swelling ratio in toluene, the tensile strength, elongation at break and biodegradation of the cured ENR were also investigated. The ester linkage at 1730 cm-1 of the cured ENR was confirmed by ATR-FTIR. The swelling in toluene of the modified ENR decreased as a function of the proportion of TA. The thermal stability of the modified ENR was enhanced significantly after chemical modification as observed by TGA. A ratio of 7 phr of TA gave good mechanical strength of the vulcanized ENR compared to other TA contents. The ENR cured with TA easily degraded in natural soil compared to NR conventionaly vulcanized with sulfur.

Authors :
Sa-Ad Riyajan, Watcharin Khiatdet and Duangporn Riyapan : Department of Materials Science and Technology, Natural Products Research Centre, And Center of Excellence in Nanotechnology for Energy, Faculty of Science, Prince of Songkla University, Songkhla 90112
Thanawadee Leejarkpai : National Metal and Materials Technology Center,114 Thailand Science Park Paholyothin Rd., Klong 1, Klong Luang, Pathumthani, 12120, Thailand.