Various coagulation techniques and their impacts towards the properties of natural rubber latex from Hevea brasiliensis — a comprehensive review related to tyre application

• Published in: Industrial crops and products Vol. 181; p. 114835
• Main Authors: Ng, Jing Wei, Othman, Nadras, Yusof, Nurul Hayati
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2022
• Subjects: coagulation; Coagulation mechanism; Green strength; Hevea brasiliensis; latex; Latex coagulation; microstructure; Properties of natural rubber; rubber; tires; Vulcanizate performance; Hevea brasiliensis; ABC; HFA; NR; Coagulation mechanism; PRI; HLL; Properties of natural rubber; ADS; VFA; Green strength; NADH; CaCl2; Latex coagulation; P0; SDS; AE; SRPs; KOH; TSC; pKa; MV; MW; SIC; MST; Vulcanizate performance; TSR; CV; RSS; DRC; HA; SMR; GPC
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2022.114835

Coagulation is the first crucial step in the processing of natural rubber (NR) that happens naturally or is induced by various techniques. The mechanism of Hevea latex coagulation involves the destabilization and aggregation of latex particles that are influenced by different factors. By understanding the basics of coagulation process, the use of different coagulation techniques and their efficiency are illustrated in this paper. The corresponding impact on the technological properties of unvulcanized NR is connected to the choice of coagulation technique. For instance, the microstructure of natural coagulated NR relies on the precedence of microbial activities which further decides the mesostructure and macrostructure properties. As NR is widely used in the rubber manufacturing industry notably tyres, the subsequent impacts of coagulated NR using different techniques are described from the aspect of processing, vulcanization characteristics, mechanical properties, and ageing retention properties of NR vulcanizate. By providing such an overview, the connection of coagulation technique of Hevea latex to the rubber industries is established to have a more comprehensive understanding when selecting the best option for the respective application. •Coagulation of Hevea latex starts with destabilization then aggregation of latex particles.•Efficiency of coagulation depends on storage, pH, ionic strength, and agronomic parameters of Hevea latex.•Various coagulation techniques are triggered by different factors respectively.•Coagulation technique decides properties of unvulcanized NR after the latex tapping process.•Properties of NR vulcanizate are directly or indirectly affected by the choice of coagulation techniques.