Effect of divalent metal ions on the viscosity of natural rubber from manihot glaziovii

Rodrigues J.F., . and Oliveira F.C., . and Ricardo N.M.P.S., . and Lima M.C.P., . Effect of divalent metal ions on the viscosity of natural rubber from manihot glaziovii. pp. 240-252. ISSN 1511-1768

The effect of divalent metal ions on the intrinsic viscosity of natural rubber (NR) from Manihot glaziovii has been investigated. The molar mass of cis-1 4-polyisoperene from manihot rubber was found to be Mv equal to 1.0 times 10 strength 6 and the intrinsic viscocity n equal to 5.66 dL per g for toluene solution at 30 degree Celcius. Some metal ions such as Ca2 and Sr2 increase the NR viscosity in toulene solution (6.00 dL per g and 6.26 dL per g for 15.0 micro mol of metal ion per g of rubber respectively). Others such as Mg2 Zn2 and Cu2 decrease the NR viscosity to 4.82 dL per g 4.73 dL per g and 4.96 dL per g respectively for the same addition of metal ion per g of rubber. A correlation between relative variation of intrinsic viscosity (nNR M per nNR) and cation radius has been proposed. A relative variation greater than unity for large cations has been observed while for small metals such variation was less than 1. Cations that decrease the intrinsic viscosity do not lead to alteration in the activation energy of flow (Ea) for the 0.5 perccent (w per v)(Ea equal to 7.3 kJ per mol) solution. Cations that increase n also cause an increase of Ea to 7.8 kJ per mol and 7.6 kJ per mol for NR solutions containing Sr2 and Ca2 respectively. Intramolecular crosslinks may be formed with small and large cations. No evident interaction has been detected between metal ions and synthetic cis-1-4-polyisoprene. The interaction between NR and metal ions may be due to naturally occuring non-rubber constituents probably those containing carboxylic groups.

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Abstract

The effect of divalent metal ions on the intrinsic viscosity of natural rubber (NR) from Manihot glaziovii has been investigated. The molar mass of cis-1 4-polyisoperene from manihot rubber was found to be Mv equal to 1.0 times 10 strength 6 and the intrinsic viscocity n equal to 5.66 dL per g for toluene solution at 30 degree Celcius. Some metal ions such as Ca2 and Sr2 increase the NR viscosity in toulene solution (6.00 dL per g and 6.26 dL per g for 15.0 micro mol of metal ion per g of rubber respectively). Others such as Mg2 Zn2 and Cu2 decrease the NR viscosity to 4.82 dL per g 4.73 dL per g and 4.96 dL per g respectively for the same addition of metal ion per g of rubber. A correlation between relative variation of intrinsic viscosity (nNR M per nNR) and cation radius has been proposed. A relative variation greater than unity for large cations has been observed while for small metals such variation was less than 1. Cations that decrease the intrinsic viscosity do not lead to alteration in the activation energy of flow (Ea) for the 0.5 perccent (w per v)(Ea equal to 7.3 kJ per mol) solution. Cations that increase n also cause an increase of Ea to 7.8 kJ per mol and 7.6 kJ per mol for NR solutions containing Sr2 and Ca2 respectively. Intramolecular crosslinks may be formed with small and large cations. No evident interaction has been detected between metal ions and synthetic cis-1-4-polyisoprene. The interaction between NR and metal ions may be due to naturally occuring non-rubber constituents probably those containing carboxylic groups.

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Item Type:	Article
Additional Information:	Summary (En)
AGROVOC Term:	MANIHOT GLAZIOVII
AGROVOC Term:	RUBBER
AGROVOC Term:	METALS
AGROVOC Term:	IONS
AGROVOC Term:	VISCOSITY
AGROVOC Term:	CATIONS
AGROVOC Term:	PROTEINS
AGROVOC Term:	ELECTROLYTES MANIHOT GLAZIOVII
AGROVOC Term:	CAUCHO
AGROVOC Term:	METALES
Depositing User:	Ms. Norfaezah Khomsan
Last Modified:	24 Apr 2025 05:52
URI:	http://webagris.upm.edu.my/id/eprint/17708

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