Degradation of Silica-Reinforced Natural Rubber by UV Radiation and Humidity in Soil

In this research study, the degradation of natural rubber was applied for applications in agriculture products such as rubber mulch. This work included the synthesis of 20% wt silica/ natural rubber composites from high ammonia concentrate latex (HA) and fresh latex (FL). They were casted by film casting. The experimental study of rubber composite degradation was done by putting the samples underground and above the soil surface under accelerated degradation test box equipped with a solar simulator lamp for a period of 50 days. Samples were characterized by scanning electron microscopy (SEM) to examine the dispersion on cross-sectional area between natural rubber and silica. Thermogravimetric analysis (TGA) was used to analyze the thermal stability of the composites. Tensile strength (MPa), modulus at 100% elongation (MPa), and elongation at break (%) of the samples after aging were tested by focusing on. It was found that thermal degradation of natural rubber compounds consisted of one step of mass loss between 341°C and 455°C. The SEM result showed good dispersion of Si in the rubber samples. Moreover, it was found that before aging, the composite samples had higher tensile strength than that of the rubber. After aging, the composite samples had lower tensile strength than that of the rubber. Elongation @ break value of HA/Si and FL/Si after aging were decreased obviously.