Alternative Natural Rubber Crops: Why Should We Care?

Natural rubber is a strategic raw material essential to the manufacture of 50,000 different rubber and latex products. Until recently, natural rubber has been produced solely from a single species, the rubber tree (Hevea brasiliensis), which is grown as genetically similar clones in tropical regions and harvested by hand. Developed countries import all the natural rubber they require: >1.2 megatons/year by the U.S. and >12 megatons/year globally. Steadily increasing demand cannot be met in the future by the rubber tree alone, and viable alternative crops that can be established on farms and managed with mechanized equipment are required. If we fail to accomplish this goal in the near future, adverse economic consequences are predicted. However, while the introduction of any new crop is extremely challenging, a new rubber crop requires parallel coordinated expansion of farm acreage and processing capacity, initially feeding high-value niche markets suited to small-scale production, but which can gradually transition to address the much larger commodity markets. Sustainability of new rubber crops depends on valorization of the entire plant and environmentally-friendly processing. In the long term, the rubber from alternate rubber crops, especially more heat-stable derivatives such as epoxidized rubber, may supplement sections of the market share currently occupied by various synthetic rubbers with enormous carbon footprint savings.