Natural rubber (NR) is an important industrial material and strategic resource. Its composition, structure, and properties are influenced by factors such as the rubber tree cultivar and processing methods, leading to significant variations in quality stability. By studying the changes in particle size and molecular weight of natural rubber prepared through different centrifugation cycles, this research explored the effects on rubber composition and performance, which is crucial for obtaining high-quality rubber. In this study, two rubber cultivars, Reyan 73397 and PR107, were selected to investigate the impact of different centrifugation cycles on the particle size of latex, molecular weight, physicochemical properties of raw rubber, and vulcanized rubber properties. After centrifugation, the particle size of the latex from both cultivars increased with the number of centrifugation cycles, and the particle size distribution became more concentrated, with Reyan 73397 having a larger particle size than PR107. The molecular weight decreased, and the molecular weight distribution narrowed as the centrifugation cycles increased. With more centrifugation cycles, the ash content, gel content, nitrogen content, and Mooney viscosity of both cultivars decreased, the vulcanization time extended, but the resistance to storage hardening increased. However, the tensile strength and tear strength were reduced. The aging resistance of the vulcanized rubber from both cultivars decreased with the increase of centrifugation cycles. Furthermore, centrifugal treatment increased the glass transition temperature (Tg) of the rubber, enhanced its resistance to wet sliding, and increased the rolling resistance and heat build-up of the rubber.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |