Innovation in natural rubber latex coagulation using CO2 microbubbles

Abstract

Traditionally, acids have been employed in the production of raw rubber sheets. Using concentrated acids to coagulate natural rubber latex has led to issues such as subpar product quality and the generation of a significant volume of acidic latex serum waste. In contrast, opting for weak acids results in increased production costs. To address these limitations, this research adopts an innovative approach that leverages CO2 microbubbles as a process intensification technique. CO2 was bubbling into a bubble column filled with fresh natural rubber latex and closely monitored the pH and coagulation percentage over time. The physical and mechanical properties of the solid rubber products were characterized, in comparison with the products gained from conventional techniques. The use of CO2 microbubbles yielded shorter processing times and reduced the generation of acidic waste serum. Notably, this approach also led to significant improvements in key properties such as initial Wallace plasticity (P0), plasticity retention index (PRI), nitrogen content, and biodegradability in soil of the rubber samples. Interestingly, the utilization of CO2 as a feedstock highlights its role in promoting a sustainable process. This innovative approach not only minimizes environmental impact but also results in the production of value-added rubber products with enhanced properties.