Citation
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
Abstract
The effect of divalent metal ions on the intrinsic viscosity of natural rubber (NR) from Manihot glaziovii has been investigated. The molar mass ofcis-l 4-polyisoprenefrom Manihot rubber was found to be M 1.0 106 and the intrinsic viscosity rj 5.66 dL/g for toluene solution at 30 C. Some metal ions such as Ca2 and 5rr2 increase the NR viscosity in toluene solution (6.00 dL/g and 6.26 dL/g for 15.0 mmol of metal ion/g of rubber respectively). Others such as Mg2 Zn2 andCu2 decrease the NR viscosity to 4.82 dL/g 4.73 dL/g and 4.96 dL/g respectively for the same addition of metal ion/g of rubber. A correlation between relative variation of intrinsic viscosity (r)NRM/riNR) 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 (w/v)(E 7.3 kJ/mol) solution. Cations that increase r/ also cause an increase of Ea to 7.8 kJ/mol and 7.6 kJ/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-l-4-polyisoprene. The interaction between NR and metal ions may be due to naturally occurring 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 ofcis-l 4-polyisoprenefrom Manihot rubber was found to be M 1.0 106 and the intrinsic viscosity rj 5.66 dL/g for toluene solution at 30 C. Some metal ions such as Ca2 and 5rr2 increase the NR viscosity in toluene solution (6.00 dL/g and 6.26 dL/g for 15.0 mmol of metal ion/g of rubber respectively). Others such as Mg2 Zn2 andCu2 decrease the NR viscosity to 4.82 dL/g 4.73 dL/g and 4.96 dL/g respectively for the same addition of metal ion/g of rubber. A correlation between relative variation of intrinsic viscosity (r)NRM/riNR) 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 (w/v)(E 7.3 kJ/mol) solution. Cations that increase r/ also cause an increase of Ea to 7.8 kJ/mol and 7.6 kJ/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-l-4-polyisoprene. The interaction between NR and metal ions may be due to naturally occurring non-rubber constituents probably those containing carboxylic groups.
Additional Metadata
| Item Type: | Article |
|---|---|
| AGROVOC Term: | Manihot glaziovii |
| AGROVOC Term: | Euphorbiaceae |
| AGROVOC Term: | Natural rubber |
| AGROVOC Term: | Viscosity |
| AGROVOC Term: | Metals |
| AGROVOC Term: | Ions |
| AGROVOC Term: | Nitrogen content |
| AGROVOC Term: | Degradation |
| AGROVOC Term: | Temperature |
| AGROVOC Term: | Cross-linking |
| Depositing User: | Ms. Suzila Mohamad Kasim |
| Last Modified: | 24 Apr 2025 06:28 |
| URI: | http://webagris.upm.edu.my/id/eprint/23328 |
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