Abstract
The effect of different ethephon concentrations 1%-5% (w/v) on colour of crepe rubber and plasticity retention index (PRI) was studied. The study was conducted with the RRISL 121 clone using S/2, d3 harvesting system. The results revealed that ethephon stimulation affects strongly the antioxidant and polyphenol oxidase (PPO) inhibitory potential. Further, thiol content and PRI values were increased while giving low Lovibond colour index upto 3% ethephon concentration and the properties were found to be inferior above 3% concentration. A probable reaction mechanism is proposed for colour improvement with optimum concentration of ethephon.
Highlights
Latex crepe is the purest form of natural rubber available in the market and Sri Lanka is the world’s leading producer of pale crepe and sole crepe for the export market (Seneviratne et al, 2003)
Tapped latex collected into vessels, immersed in ice and send to the laboratory immediately for the analysis of sucrose and thiol content without preservation and the other fraction was processed into unfractioned un-bleached crepe rubber (UFUB)
With s/2 d/3tapping system, the thiol content and plasticity retention index increases up to 3% and above that concentration the properties were drastically reduced with increasing ethephon concentration (Table 1)
Summary
Latex crepe is the purest form of natural rubber available in the market and Sri Lanka is the world’s leading producer of pale crepe and sole crepe for the export market (Seneviratne et al, 2003). Discoloration due to ethephon stimulation has been reported (Yapa, 1976), there is no evidence for the effect of ethephon concentration on colour of crepe rubber. With the presence of polyphenol oxidase, phenols and amino phenols combine with oxygen from air to form orthoquinones. These orthoquinones react with naturally occurring amino acids and proteins in latex, giving coloured compounds resembling melanin (Mason, 1955). Both polyphenol oxidase (PPO) and phenolic substances are present in latex but do not react with each other intact laticifers. New insight into ethephon stimulation the objective of the present study was to investigate the effect of ethephon concentration on latex discolouration and underpinning reasons
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
