Effect of maturation on the bulk viscosity and molecular chain length of cuplump natural rubber

Ehabe, Ejolle Eugène; Roux, Yannick Le; Ngolemasango, F.; Bonfils, Frédéric; Nkeng, George Elambo; Nkouonkam, B.; Sainte‐Beuve, Jérôme; Gobina, M. S.

doi:10.1002/app.10968

Cited by 18 publications

(18 citation statements)

References 34 publications

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“…Although the PRI of rubber from clones PB 235 and PB 217 remained almost constant throughout, those from clone GT 1 decreased significantly following prolonged maturation and storage for 45 days. The differences observed for the various clones would indicate some inherent differences in the nonrubber constituents of the clones studied and/or a discriminatory effect of maturation (leaching, denaturing, and deactivation), depending on the clonal origin of the rubber 12…”

Section: Resultsmentioning

confidence: 99%

“…Even the effects of some agronomic traits of the Hevea plant on the bulk behavior of its rubber have been postulated. Indeed, significant relationships have been confirmed between some relevant bulk properties of raw rubber and some physiological parameters of Hevea latex (inorganic phosphorus and total solids content),11 as well as on the effects of coagula maturation and storage on the macromolecular chain length of raw natural rubber of different clonal typologies 12. This study was undertaken to investigate the contribution of coagula maturation prior to factory processing (washing and drying) on the flow behavior of natural rubber, the cure behavior of its pure gum (ACS 1) compounded stocks, and the mechanical properties of its vulcanizates.…”

Section: Introductionmentioning

confidence: 96%

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Effect of natural coagula maturation on the processability, cure, and mechanical properties of unfilled vulcanizates of Hevea natural rubber

Fri

Nkeng

Ehabe

2006

J of Applied Polymer Sci

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Fresh latex from different Hevea brasiliensis clones was naturally coagulated, subjected to different durations of maturation, processed into solid rubber, and compounded into pure gum stocks and vulcanized. Coagula maturation had clone-specific effects on the processability of the raw rubber: reduced for some clones, while others was less sensitive. The cure and mechanical behaviors of the compounded stocks and vulcanizates, respectively, were not sensitive to the clonal origin of coagula and their duration of maturation. Although coagula maturation could be associated with leaching, deactivation of inherent antioxidants in Hevea latex, as well as crosslinking and/or oxidation of polyisoprene chains, these results show that compounding with a standard pure gum recipe compensates for the Hevea latex constituents affected by maturation. Hence, extended maturation of Hevea coagula, for economic or other reasons, would influence much more the bulk behavior of raw rubber and have insignificant effects on the compounded stocks and vulcanizates.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Effect of natural coagula maturation on the processability, cure, and mechanical properties of unfilled vulcanizates of Hevea natural rubber

Fri

Nkeng

Ehabe

2006

J of Applied Polymer Sci

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“…This increase of the gel content is quite variable, from a negligible value in some cases (about 1%) to about 25% for others studies (Ehabe et al . ; Cocard et al . ; Intapun et al .…”

Section: Introductionmentioning

confidence: 99%

Micro-organisms in latex and natural rubber coagula ofHevea brasiliensisand their impact on rubber composition, structure and properties

et al. 2014

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Summary Natural rubber, produced by coagulation of the latex from the tree Hevea brasiliensis, is an important biopolymer used in many applications for its outstanding properties. Besides polyisoprene, latex is rich in many nonisoprene components such as carbohydrates, proteins and lipids and thereby constitutes a favourable medium for the development of micro‐organisms. The fresh rubber coagula obtained by latex coagulation are not immediately processed, allowing the development of various microbial communities. The time period between tree tapping and coagula processing is called maturation, during which an evolution of the properties of the corresponding dry natural rubber occurs. This evolution is partly related to the activity of micro‐organisms and to the modification of the biochemical composition. This review synthesizes the current knowledge on microbial populations in latex and natural rubber coagula of H. brasiliensis and the changes they induce on the biochemistry and technical properties of natural rubber during maturation.

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“…To obtain dry products, NR latex is subjected to several treatments. Traditionally, rubber is rapidly coagulated from latex, treated to eliminate serum, appropriately dried and baled [1,2] .…”

Section: Introductionmentioning

confidence: 99%

Thermooxidative degradation and its kinetics of natural rubber coagulated by microwave radiation

Liao¹,

Liao²,

Li³

et al. 2012

Journal of Polymer Engineering

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The thermooxidative degradation of natural rubber (NR) coagulated by microwave radiation (NR-m) was investigated by thermogravimetry (TG) analysis, and compared with NR coagulated by acid (NR-a). It was found that the degradation process is not a one-step reaction, the main degradation process occurs at 300 -400 ° C, and the equilibrium degradation temperatures of NR-m are higher than those of NR-a. Different methods were used to find the most probable kinetic model and the Arrhenius para meters (activation energy E and preexponential factor A ) for the main stage of thermooxidative degradation of NR-m. The results show that the values of E and A , obtained from the Coats-Redfern method, are highly variable with the kinetic model chosen and the heating rate ( β ), and the apparent activation energy ( E 0 ) when β approaches zero for the D n type kinetic model is in the range of 96.7 -106.4 kJ · mol -1 . The mean values of E , calculated by the Friedman and Flynn-Wall-Ozawa (FWO) methods, are 113.8 and 83.3 kJ · mol -1 , respectively, suggesting E in the range of 83.3 -113.8 kJ · mol -1 . Comparison of these two ranges indicates the most probable kinetic model to be D n type kinetic models, corresponding to a diffusion-controlled mechanism.

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Effect of maturation on the bulk viscosity and molecular chain length of cuplump natural rubber

Cited by 18 publications

References 34 publications

Effect of natural coagula maturation on the processability, cure, and mechanical properties of unfilled vulcanizates of Hevea natural rubber

Effect of natural coagula maturation on the processability, cure, and mechanical properties of unfilled vulcanizates of Hevea natural rubber

Micro-organisms in latex and natural rubber coagula ofHevea brasiliensisand their impact on rubber composition, structure and properties

Thermooxidative degradation and its kinetics of natural rubber coagulated by microwave radiation

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