The enhancement of cure and mechanical properties of natural rubber vulcanizates with waste Aquilaria crassna wood

Aquilaria crassna wood (WAC) waste was studied to reduce waste and use it as an alternative filler for rubber industry, by preparing masterbatches with varying WAC contents (0, 20, 40, and 60 phr). Dry mixing was also tested for comparison. The effects of WAC on curing characteristics, crosslink density, and mechanical, dynamic, and thermal properties were investigated. The results indicate that the masterbatch with 20 phr of WAC was near optimal. It showed a lower scorch time than control sample. That is, scorch time decreased from 1.4 min for Latex/WAC0 to 1.1 min for Latex/WAC20. This is because WAC contains some metals that activate vulcanization reactions. Thus WAC filler is beneficial in terms of reducing the cost of processing rubber to vulcanizates. In addition, the masterbatch with 20 phr of WAC showed high delta torque at 10.1 dN m, Mooney viscosity at 28.1 +/- 0.5, crosslink density at 250 mol/m3, and hardness at 44 Shore A. It was also found that 20 phr of WAC gave a good filler dispersion and the highest glass transition temperature (T g) at -41.2 degrees C, indicating strong fillermatrix interactions. Moreover, the masterbatch method exhibited overall better properties than the dry mixing method. This choice of processing method as well as compatibility of filler and matrix both affected the end results. Furthermore, the alternative filler use serves to reduce/recycle waste.

Automated summary

The study found that 20 phr of Aquilaria crassna wood waste filler performed best in the rubber industry, reducing processing costs and exhibiting good mechanical and thermal properties. Rubber masterbatches prepared using the filler showed better filler dispersion and glass transition temperature than dry mixing method.