Determination of hydrogenated natural rubber (HNR) bearing pad vulcanizate performance based on thermal oxidative resistance characteristic

Isolation systems to protect a bridge structure often use steel-laminated elastomeric bridge bearing pad based on natural or chloroprene rubber. Supply of imported chloroprene rubber becomes the main constrain to produce high-quality elastomeric bridge bearing pad especially which has superior thermal-oxidative resistance. The research was aimed to study the possibility of hydrogenated natural rubber (HNR) as an alternative base elastomer to substitute mainly synthetic chloroprene rubber in the production of elastomeric bridge bearing pad. HNR was compounded at various capacities (300, 900, and 2700 g) to investigate the quality consistency. The procedure of HNR compounding referred to ASTM D 3182. HNR vulcanizate was characterized mainly in accordance with elastomeric bridge bearing pad standard requirement as stated in SNI 3967:2013 Duro 60. The result showed that all of the bearing pad vulcanizate were produced at any capacity had hardness value that filled the SNI 3967:2013 requirement since the difference of hardness value due to aging condition as max 5 point. While the ozone resistant parameter was only proper to natural rubber bearing pad specification. The low tensile properties and compression set values were caused by the short HNR molecular chain and less flexibility of the crosslink networks. Both factors inhibited strain-induced crystallization of the HNR molecular chain during stretching. HNR vulcanizates showed good performance on UV weathering resistance. Referred to the results, it could be concluded that HNR was potential to be developed as alternating base elastomer on elastomeric bridge bearing pad production although it remains necessary to conduct compound reformulation procedure at a higher capacity of production.