Characterization of enzyme‐deproteinized skim rubber

Abstract

Skim natural rubber latex is a protein-rich byproduct obtained during the centrifugal concentration of natural rubber latex. Skim latex has a very low dry rubber content (4-8%), and the rubber particles are smaller in size. It has a higher proportion of nonrubber solids, which are mostly proteinaceous in nature. It is difficult to coagulate, and it takes more processing time. The proteins in skim latex can be decomposed by proteolytic enzymes. This article discusses the use of stabilized liquid papain from the papaya plant (Carica papaya) for deproteinization followed by creaming for quick and easy coagulation of skim latex. The technological properties and aging characteristics of the deproteinized skim rubber are compared with those of conventionally prepared skim rubber and block rubber. The deproteinized skim rubber showed enhanced quality parameters. Particle size analysis revealed that deproteinization and creaming of the skim latex did not markedly change the particle size. Gel permeation chromatography showed a reduction in the quantity of fatty acids after deproteinization and creaming, which was reflected in the improvement of the aging characteristics in comparison with the control sample. Vulcanizates prepared with the deproteinized skim rubber had higher resilience, lower heat buildup, lower compression set, and good tensile strength and elongation at break in comparison with conventionally prepared skim rubber, and the properties were almost comparable to those of block rubber. The improvement in the mechanical properties and aging characteristics could be attributed to the reduction of the protein content, the partial removal of unsaturated fatty acids, and the removal of metal ions that were pro-oxidants during the deproteinization and creaming process.

Influence of phenolic curative on crosslink density and other related properties of dynamically cured NR/HDPE blends

“…It is therefore concluded that the higher degree of crosslinking in the TPVs caused increasing tensile strength but decreased degree of swelling in the IRM903 oil. This result agrees with previous work21–24 which stated that the TPVs exhibited higher tensile strength than corresponding unvulcanized blends. In Figure 4, the elongation at break also increased with increasing crosslink density (Fig.…”

Enhanced Kinetic Performance of CLEA-Lipase Extracted from Skim Latex of Hevea brasiliensis upon Immobilization on Magnetic Iron Nanoparticles

“…Skim latex is the by-product of the natural rubber processing industry and can be considered as the most polluting waste that comes out of it. This is because, besides the residual 4 to 8% dry rubber content [2], skim latex also contains the pungent-smelled ammonia that was necessarily added to stabilize the field latex. As per standard operation procedure, skim latex should be pre-treated in the effluent treatment oxidation pond, before the cleaner water from the pond is periodically released into the main waterways.…”

Characterization the rheology behavior of modified skim rubber

“…Howerver, it has about 95% rubber hydrocarbon and 2% protein in natural rubber. [2] Standard of chinese rubber (SCR) is classificated natural rubber in china, and it includes SCR-WF, SCR-5, SCR-10, SCR-20. According to chinese standard (GB/T 8081-2008), identified grade of natural rubber is accorded to impurity, ash, nitrogen, volatile matter, P 0 and PRI (for short: six indexes).…”