Abstract:

The structure of natural rubber (NR) is not only affected by the biosynthesis of rubber trees, but also has a lot to do with the processing technology. In order to scientifically compare the effects of the processing technology, in this paper, the latex produced by the same rubber tree was collected to prepare NR using five typical processing technologies according to the current factory production conditions, namely WF, RSS, ADS, CV, TSR. The analysis of the raw rubber structure showed that the decomposition of non-rubber components and the structuring of rubber hydrocarbons caused by maturation would occur during the processing. The specific manifestations were reduced nitrogen content, increased number average molecular weight, narrowed molecular weight distribution, and higher gel content, which caused the increase of initial value of plasticity and Mooney viscosity. Among them, TSR had the highest degree of structure, while CV could retain its inherent molecular structure and had the lowest degree of structure. The performance analysis of the vulcanizates showed that the decomposition of non-rubber components was beneficial to increasing the curing rate and crosslinking density of natural rubber, thereby improving the static mechanical properties of the vulcanizates. The structuring of the rubber hydrocarbon could increase the physical entanglement in the vulcanizates. The network made it more prone to strain-induced crystallization and improve dynamic fatigue performance by increasing energy dissipation. Taken together, the order of the static and dynamic mechanical properties of vulcanizates is: TSR > ADS > RSS > WF > CV.

Key words: natural rubber, processing technology, structure, static mechanical properties, dynamic mechanical properties