Thermal and photo oxidative degradation of natural rubber film in the presence of iron (III) stearate

• Main Authors: Azhar, Natasya Nabilla Hairon, Cheng, Acga, Lee, Siang Yin, Ang, Desmond Teck Chye
• Format: Article
• Published: Springer 2022
• Subjects: QD Chemistry
• Online Access: http://eprints.um.edu.my/40730/

The use of pro-degradant additive (PDA) to enhance the oxidative degradability of polymers has been successful in hydrocarbon plastics, but few, if any studies have been conducted to evaluate the effect of PDA on natural rubbers. This study investigated thermal, and photo oxidative degradation of natural rubber facilitated by iron (III) stearate as PDA. For a total of eight weeks, natural rubber compounded with PDA was subjected to thermal and photo oxidation separately. Spectroscopic analysis was used to quantify changes in the chemical structure of the rubber, including the formation of carbonyl, hydroxyl, and ether linkages. The changes in the surface hydrophilicity, crystallinity, and thermal properties of the rubber throughout the degradation process were evaluated as well. PDA-containing natural rubber film exhibited greater oxidative degradation, as evidenced by a significant increase in carbonyl index, a decrease in water contact angle, and a lower decomposition temperature. Between the two modes of degradation, natural rubber was found to degrade better in the presence of light. The apparent improvement in the oxidative degradability of the rubber following the incorporation of the iron salt suggests that the material could be formulated or developed as oxo-biodegradable rubber to promote more sustainable consumption. Oxidative degradation is a crucial process that converts rubber into shorter chains with a higher concentration of oxygen-carrying functional groups, and these changes are required to support the subsequent biodegradation process, resulting in a more environmentally friendly material.