"Quick evaluation method of ozone aging resistance for natural rubber vulcanizate"

Abstract

The effects of elongation, ozone volume concentration, relative humidiy on ozone aging resistance of natural rubber (NR) vulcanizates had been investigated. A quick evaluation method of ozone aging resistance for NR vulcanizate was established. The appropriate type and amount of protective wax for NR vulcanizate were optimized by this method. Test results showed that the ozone cracking began to appear on the surface of samples and the degree of cracking gradually increased with higher elogation and ozone volume concentration as well as relative humidity. The test condition of 50% maximum elongation and 1.00×10-4% ozone volume fraction with 50% relative humidity at 40 ℃ could characterize the resistance to ozone aging of NR vulcanizates filled with carbon black quickly. The protective wax with high content of non-normal pafaffins and intermediate carbon paraffins had good protection effect of static ozone for NR vulcanizates. Using this quick evaluation method, protective wax A was found to have better performance of ozone aging resistance for NR vulcanizate. And the optimum amount of protective wax A was 3 phr.

Keywords

• natural rubber
• vulcanizate
• ozone aging resistance
• protective wax
• elongation
• ozone concentration
• relative humidity