Sustainability of prevulcanization of natural rubber latex: a comparative assessment of sulfur-based and radiation-based processes

Prevulcanization of natural rubber (NR) latex is a key process in producing diverse rubber products, as it governs their mechanical performance. Conventional sulfur prevulcanization is widely used owing to its simplicity and low cost, yet it poses environmental and health concerns due to zinc-based accelerators and sulfur compounds. This study compared five prevulcanization processes (sulfur-based; UV irradiation from fluorescent lamps, UV-Flu; UV from light emitting diodes, UV-LED; electron beam, EB; X-ray irradiation) using life cycle analysis (LCA) and life cycle cost analysis (LCCA). Laboratory experiments established the life cycle inventory (LCI) for processes that were then scaled up to industrial production scenarios. Measurements confirmed that all processes produced films that met ASTM requirements (Standard D3578–19). The LCA showed that EB irradiation minimized the environmental burdens because of short irradiation times and high throughput. X-ray prevulcanization resulted in the highest impact, driven by a high energy requirement and low productivity. UV-LED outperformed UV-Flu, reflecting higher efficiency of LED lamps and their longer life compared to fluorescent lights. The LCCA revealed sulfur-based process to be the most economic (US$ 1.48 kg−1), followed by UV-LED (US$ 4.38 kg−1) and the EB (US$ 10.56 kg−1). The X-ray process was prohibitively expensive (US$ 203.83 kg−1) and environmentally the most burdensome. Overall, the UV-LED and EB processes were most sustainable, especially if these technologies were developed further to reduce energy input and the hardware costs.