Ammonia-free latex preservative systems: past, present and future outlook

Abstract

Malaysia is one of the world’s largest producers of natural rubber latex (NRL), making an important contribution to its gross domestic product (GDP). However, NRL is highly susceptible to microbial contamination. This leads to spontaneous coagulation once it leaves the rubber tree, reducing yield and necessitating the use of latex preservation systems. Ammonia is widely used as commercial preservatives for latex stabilisation. However, the incorporation of ammonia into latex has long been shown to negatively impact both the environment and the well-being of latex industry workers and consumers of latex products. The multiple disadvantages of ammonia in latex formulations, such as undesirable odour, toxicity, volatility, health and environmental issues, have therefore highlighted the need for the development of new and innovative latex preservative systems that are free of ammonia. This paper begins with a comprehensive overview of NRL production, preservation and its history. It then covers the production of ammonia, its main applications in latex, and the drawbacks associated with its synthesis and use in latex stabilisation. Additionally, the review explores alternative non-ammonia latex stabilisers in detail, highlighting their advantages compared to ammonia, the pros and cons of these stabilisers, and the sustainability of ammonia-free latex preservative systems for future industrial applications.