Clonal characterisation of latex and rubber properties

Esah Yip, . Clonal characterisation of latex and rubber properties. pp. 52-80. ISSN 0127-7065

Properties of latex and bulk rubber from Hevea clones of commercial interest have been studied. These include the Class I Class II and some new Class IIIA clones described in the Rubber Research Institute of Malaysia (RRIM) Planting Recommendations. Latices collected under standard conditions from about 100 trees of each clone and processed into latex concentrates and bulk rubbers using a fixed procedure were investigated. Clonal differences have been observed in almost all the properties examined. Possible influences of various latex components and other factors on the variability of some of the properties are discussed. Generally most clones produce latex concentrates with fairly good latex stability although added soap is needed in some cases. The mechanical stability of a few unstable clones however remain low due to poor response to the soap treatment. All other properties tested meet the specifications for latex concentrate. While the RRIM clones often yield rubbers with low to medium viscosities those from the PB (Prang Besar) clones generally tend to be of relatively high viscosity. The inclusion of comparatively few rubber clones with low viscosity in the Recommendations is noted. Latices from all clones are suitable for commercial production of SMR non-viscosity-stabilised rubbers while clones which can be processed into SMR CV60 grade without blending with other latices have been identified. Twenty-five clones have been observed to yield light-coloured rubbers consistently. Good correlations are observed between Mooney viscosity and initial Wallace plasticity of both non-CV and CV rubbers of these clones. Their cure characteristics such as the torque change (DT) and the relaxed modulus (MRIOQ) are also significantly correlated.

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Abstract

Properties of latex and bulk rubber from Hevea clones of commercial interest have been studied. These include the Class I Class II and some new Class IIIA clones described in the Rubber Research Institute of Malaysia (RRIM) Planting Recommendations. Latices collected under standard conditions from about 100 trees of each clone and processed into latex concentrates and bulk rubbers using a fixed procedure were investigated. Clonal differences have been observed in almost all the properties examined. Possible influences of various latex components and other factors on the variability of some of the properties are discussed. Generally most clones produce latex concentrates with fairly good latex stability although added soap is needed in some cases. The mechanical stability of a few unstable clones however remain low due to poor response to the soap treatment. All other properties tested meet the specifications for latex concentrate. While the RRIM clones often yield rubbers with low to medium viscosities those from the PB (Prang Besar) clones generally tend to be of relatively high viscosity. The inclusion of comparatively few rubber clones with low viscosity in the Recommendations is noted. Latices from all clones are suitable for commercial production of SMR non-viscosity-stabilised rubbers while clones which can be processed into SMR CV60 grade without blending with other latices have been identified. Twenty-five clones have been observed to yield light-coloured rubbers consistently. Good correlations are observed between Mooney viscosity and initial Wallace plasticity of both non-CV and CV rubbers of these clones. Their cure characteristics such as the torque change (DT) and the relaxed modulus (MRIOQ) are also significantly correlated.

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Item Type:	Article
AGROVOC Term:	Hevea rubber
AGROVOC Term:	Latex
AGROVOC Term:	Clones
AGROVOC Term:	Drying
AGROVOC Term:	Temperature
AGROVOC Term:	Extraction in chemical analysis
AGROVOC Term:	Acetone
AGROVOC Term:	Chemical analysis (methods)
AGROVOC Term:	Physical properties
AGROVOC Term:	Synthetic rubber
Geographical Term:	Malaysia
Depositing User:	Ms. Suzila Mohamad Kasim
Last Modified:	28 Apr 2025 04:43
URI:	http://webagris.upm.edu.my/id/eprint/23495

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