Development of natural rubber with enhanced oxidative degradability

• Main Authors: Azhar, Natasya Nabilla Hairon, Cheng, Acga, Lee, Siang Yin, Rahman, Nor Mas Mira, Ang, Desmond Teck-Chye
• Format: Article
• Published: Springer Verlag (Germany) 2023
• Subjects: QD Chemistry
• Online Access: http://eprints.um.edu.my/39562/

A persistent increase in the amount of rubber waste in the environment could herald the next environmental crisis. Elastomeric properties of natural rubber are relevant and essential for a wide range of applications, and because of the heavy utilization, there is a huge amount of rubber waste produced. Rubber waste, like most hydrocarbon polymers, does not readily degrade when discarded in the environment, resulting in excessive accumulation over time. Hence, novel or innovative approaches to improving natural rubber degradability are required for better waste management. The aim of the present study is to evaluate the effectiveness of metal stearates in enhancing the thermal oxidative degradability of natural rubber. Natural rubbers were blended individually with cobalt (II) stearate and iron (III) stearate, and the compounded rubbers were subsequently thermally treated in an oxidative environment at 65 degrees C for up to 8 weeks. Throughout the degradation period, the rubber films were characterized by FTIR, H-1-NMR, C-13-NMR, water contact angle, molecular weight analysis, and thermogravimetric analysis. Rubber films compounded with metal stearates experienced 1200% increase in carbonyl content, significant increase in hydrophilicity, and reduction in molecular weight by greater than 80%. These changes are highly desirable in the context of oxo-biodegradable materials because they could facilitate the subsequent biotic degradation process. The findings in this study indicate that metal stearates are efficient in enhancing the rubber's oxidative degradability. The technology may be adopted to innovate oxo-biodegradable rubbers for a more sustainable rubber consumption.