Characterization of mesostructure of natural rubber
To study NR mesostructure (macromolecular structure + aggregates or gels) (Figure 1), the NR sample is placed in a good solvent of polyisoprene (cyclohexane, toluene or tetrahydrofuran). In addition to a soluble fraction, there is always an insoluble fraction called macrogel (Figure 1) or gel depending on the authors [1-4]. The gel fraction of NR not only consists of an insoluble fraction or macrogel, but also includes a fair quantity of microaggregates or microgels (sphere-like or core-shell structure) distributed in the soluble fraction with the polyisoprene macromolecules (random coil structure) (Figure 1) [5]. The gel in NR formed because of associations between poly(cis-1,4-isoprene) chains due to interactions with non-isoprene compounds (proteins [6-7] and lipids [8]). The characterization of NR mesostructure by separative methods coupled to a multiangular light scattering (MALS) detector is presented. The separative methods used were size exclusion chromatography (SEC) [5,9] and asymmetrical field field-flow fractionation (AsFlFFF) [10]. These two techniques offer the opportunity to fully characterize NR mesostructure (average molar masses, size, microaggregates, conformation, and gel contents). Two examples of AsFlFFF-MALS use are presented: (i) characterization of NR mesostructure from different Hevea brasiliensis genotypes, (ii) characterization of the dynamic structuring of NR. A focus is on microaggregates with sizes smaller than 1 μm (Gel<1μ). They were purified by SEC and analyzed by TEM [11]. The different changes in the microaggregate structure after mastication (thermal or mechanical) were also studied [12]. Lastly, the relation with the protein content and crosslink density of the macrogel [13] is presented.
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| Format: | conference_item biblioteca |
| Language: | eng |
| Published: |
Prince of Songkla University
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| Subjects: | Q60 - Traitement des produits agricoles non alimentaires, F60 - Physiologie et biochimie végétale, |
| Online Access: | http://agritrop.cirad.fr/586212/ http://agritrop.cirad.fr/586212/2/ID586212.pdf |
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| Summary: | To study NR mesostructure (macromolecular structure + aggregates or gels) (Figure 1), the NR sample is placed in a good solvent of polyisoprene (cyclohexane, toluene or tetrahydrofuran). In addition to a soluble fraction, there is always an insoluble fraction called macrogel (Figure 1) or gel depending on the authors [1-4]. The gel fraction of NR not only consists of an insoluble fraction or macrogel, but also includes a fair quantity of microaggregates or microgels (sphere-like or core-shell structure) distributed in the soluble fraction with the polyisoprene macromolecules (random coil structure) (Figure 1) [5]. The gel in NR formed because of associations between poly(cis-1,4-isoprene) chains due to interactions with non-isoprene compounds (proteins [6-7] and lipids [8]). The characterization of NR mesostructure by separative methods coupled to a multiangular light scattering (MALS) detector is presented. The separative methods used were size exclusion chromatography (SEC) [5,9] and asymmetrical field field-flow fractionation (AsFlFFF) [10]. These two techniques offer the opportunity to fully characterize NR mesostructure (average molar masses, size, microaggregates, conformation, and gel contents). Two examples of AsFlFFF-MALS use are presented: (i) characterization of NR mesostructure from different Hevea brasiliensis genotypes, (ii) characterization of the dynamic structuring of NR. A focus is on microaggregates with sizes smaller than 1 μm (Gel<1μ). They were purified by SEC and analyzed by TEM [11]. The different changes in the microaggregate structure after mastication (thermal or mechanical) were also studied [12]. Lastly, the relation with the protein content and crosslink density of the macrogel [13] is presented. |
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