Distribution of molar mass and branching index of natural rubber from Hevea brasiliensis trees of different age by size exclusion chromatography coupled with online viscometry
The Medical Journal of Malaysia
;
: 214-215, 2004.
Artigo
em Malaiala
| WPRIM
| ID: wpr-629967
ABSTRACT
Natural rubber from hevea brasiliensis trees (Thailand, RRIM 600 clone) of different age (8, 20, and 35 years) were characterized by size exclusion chromatography coupled with online viscometry according to their distribution of molar mass and branching index at a temperature of 70 degrees C using cyclohexane as solvent. Washing with an aqueous solution of sodium dodecylsulfate and subsequent saponification purified the natural rubber samples. With this procedure physical branching points caused by phospholipids, proteins and hydrophobic terminal units, mainly fatty acids, of the natural rubber (cis-1,4-polyisoprene) molecule, could be removed leading to completely soluble polymer samples. All samples investigated possess a very broad (10 to 50,000 kg/mol) and distinct bimodal molar mass distribution. With increasing age the peak area in the low molar mass region decreases favoring the peak area in the high molar mass region. By plotting the branching index as a function of the both, the molar mass and the age of the trees.
Texto completo:
DisponíveL
Índice:
WPRIM (Pacífico Ocidental)
Assunto principal:
Borracha
/
Viscosidade
/
Sistemas On-Line
/
Cromatografia em Gel
/
Fatores Etários
/
Hevea
/
Peso Molecular
País/Região como assunto:
América do Sul
/
Brasil
Idioma:
Malaiala
Revista:
The Medical Journal of Malaysia
Ano de publicação:
2004
Tipo de documento:
Artigo
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