Characterisation of macrogel composition from industrial natural rubber samples: Influence of proteins on the macrogel crosslink density

Rolère, Sébastien; Bottier, Céline; Vaysse, Laurent; Sainte‐Beuve, Jérôme; Bonfils, Frédéric

doi:10.3144/expresspolymlett.2016.38

Cited by 27 publications

(10 citation statements)

References 32 publications

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“…This is in agreement with the correlation between the protein content and the gel content [49], which suggested that proteins were involved in the majority of crosslinks in NR [45,50]. Furthermore, these proteins were also suggested to be involved in the structuring of microaggregates, also called as "microgel" [44]. Of course, we cannot rule out completely the PMMA graft polymer may also lead to the restriction of the large-scale relaxation of NR-g-PMMA.…”

Section: Rheological Properties Of the Parent Polymerssupporting

confidence: 83%

“…This behavior may be attributed to the network of crosslinked chains (e.g., microgels), which restricted the long-range motion of chains. Works have been reported that the extracted NR contained nitrogen-containing compounds even after extensive purification [43,44]. These nitrogeneous compounds, namely proteins and phospholipids, formed an intermolecular interaction at the NR chain ends via hydrogen bonding, which possibly formed branching and gels [43,45,46], as a naturally occurring network [47,48].…”

Section: Rheological Properties Of the Parent Polymersmentioning

confidence: 99%

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Melt Rheological Behavior and Morphology of Poly(ethylene oxide)/Natural Rubber-graft-Poly(methyl methacrylate) Blends

2020

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The influence of morphology on the rheological properties of poly(ethylene oxide) (PEO) and natural rubber-graft-poly(methyl methacrylate) (NR-g-PMMA) blends in the melt was investigated. The blends were prepared at different blend compositions by a solution-casting method. Linear viscoelastic shear oscillations measurements were performed in order to determine the elastic and viscous properties of the blends in the melt. The rheological results suggested that the blending of the two constituents reduced the elasticity and viscosity of the blends. The addition of an even small amount of NR-g-PMMA to PEO changed the liquid-like behavior of PEO to more solid-like behavior. Morphological investigations were carried out by optical microscopy to establish the relationship between morphology and melt viscosity. Depending on the blend compositions and viscosities, either droplet–matrix or co-continuous morphologies was observed. PEO/NR-g-PMMA blends exhibited a broad co-continuity range, and phase inversion was suggested to occur at the PEO/NR-g-PMMA blend with a mass ratio of 60/40 (m/m), when NR-g-PMMA was added to PEO as a matrix.

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Section: Rheological Properties Of the Parent Polymerssupporting

confidence: 83%

Section: Rheological Properties Of the Parent Polymersmentioning

confidence: 99%

Melt Rheological Behavior and Morphology of Poly(ethylene oxide)/Natural Rubber-graft-Poly(methyl methacrylate) Blends

2020

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“…Another probable cause of variations is that drying and chewing are not rigorously controlled in small plantations. It has been reported that molecular weight and gel content in NR vary markedly with the drying conditions after washing with water, because storage hardening takes place after drying even if the natural rubber is left to stand at room temperature [10].…”

Section: Properties Of Nr Sheets-based Compoundsmentioning

confidence: 99%

“…These yields to variability in NR properties, what generates loss of materials and energy during the various stages of industrial processes [10]. Variations can be explained because NR latex is a very complex colloidal system.…”

Section: Introductionmentioning

confidence: 99%

Variation of technological properties of field natural rubber lattices from Hevea brasiliensis clones and natural rubber-based compounds

Vásquez¹,

Velásquez-Restrepo²

2017

DYNA

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Natural rubber (NR) is a widely used biopolymer, but the variability of its properties is a great disadvantage. In this work, variation during a 6-month period of total solids (TSC), dry rubber (DRC), ash, volatile-matter, and nitrogen content of field natural rubber (NR) lattices and mechanical properties of NR solid sheets-based compounds was studied. NR samples were collected from IAN 710, IAN 873 and FX 3864 clones of Hevea brasiliensis at a plantation within the state of Antioquia, Colombia. Rainfall, environmental temperature, relative humidity, and sunlight hours were daily registered. NR sheets-based compounds were manufactured and their rheometric and mechanical properties were measured. Significant variations (p<0.05) among clones and tappings for most of the measured properties were found. Leaf senescence was the phenological stage that presented the greatest influence on NR properties. Some recommendations to control the variation of properties of raw NR during manufacturing of rubber goods were stated.Keywords: Natural rubber; process control; variability in raw materials; rubber testing.Variación de las propiedades tecnológicas de látex de campo de caucho natural de variedades clonales de Hevea brasiliensis y de compuestos de caucho natural ResumenEl caucho natural (NR) es un biopolímero ampliamente usado, pero la variabilidad de sus propiedades es una gran desventaja. En este trabajo se estudió la variación del contenido de caucho seco (DRC), total de sólidos (TSC), cenizas, material volátil y nitrógeno de látex de campo de NR, así como de las propiedades mecánicas de compuestos basados en láminas sólidas de NR, evaluando muestras recolectadas durante 6 meses. Las muestras se obtuvieron de tres variedades clonales de Hevea brasiliensis -IAN 710, IAN 873 and FX 3864-cultivadas en una plantación en Antioquia, Colombia. En el cultivo donde se recolectó el látex se monitorearon diariamente pluviosidad, temperatura ambiente, humedad relativa y horas de sol. Se moldearon compuestos emplenado láminas de NR, determinando sus parámetros reométricos y sus propiedades mecánicas. Se encontraron diferencias estadísticamente significativas (p<0.01) para la mayoría de las propiedades evaluadas como efecto de la variedad clonal y la época de recolección. La defoliación fue la etapa fenológica que presentó la mayor influencia sobre las propiedades del NR. Se presentan algunas recomendaciones para controlar la variación de las propiedades del NR durante la fabricación de artículos con este material.Palabras clave: caucho natural; control de procesos; variabilidad en materias primas; ensayos a cauchos.

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“…It has reported that NR and deproteinised NR could not proceed with storage hardening after lipid/phospholipid groups linked to NR molecules were decomposed by transesterification reaction while the role of proteins in storage hardening is negligible [8]. On the contrary, the macrogel of various commercial grades of NR samples after at least 14 months of storage was found to contain a high content of nitrogen [15]. It was proposed that proteins are involved in the majority of crosslinks in macrogel.…”

Section: Introductionmentioning

confidence: 99%

Impact of non-rubber components on the branching structure and the accelerated storage hardening in Hevea rubber

2020

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Natural rubber (NR) contains cis-1,4-polyisoprene as well as a small quantity of non-rubber components, affecting the physical properties of NR, especially the storage hardening via gel formation. The free and/or linked non-rubber components were removed from NR by various treatments. The origin of gel formation in NR mainly resulted from proteins, which could be removed by enzymatic deproteinisation, surfactant washing or saponification treatment, and partly from phospholipids linked to NR molecule via H-bonding, which were decomposed by saponification or polar solvent treatment. The effect of the nonrubber components in NR on storage hardening was investigated by an accelerated storage hardening test (ASHT). The crude NR (CNR) containing proteins and lipids clearly showed the increase of gel content, suggesting the formation of crosslink structure during storage, resulting in the high plasticity number and Mooney viscosity after the ASHT. The gel content in protein-free NR did not change significantly only in washed NR (WSNR), but increased in the enzymatic deproteinised NR (DPNR). This resulted from the presence of residual proteins, such as oligopeptides. Interestingly, the gel content also reduced in the acetone extracted CNR (AE-CNR) and there was no significant effect on the storage hardening after ASHT, like WSNR. These were supposed to be due to the interaction or the participation of proteins and free fatty acids in the branching formation. Although the saponification could be decomposed branching at both terminal ends of the NR molecule, the protein and lipid residues occluded in the saponified NR (SPNR) affected the storage hardening. However, the flocculant remaining in the SPNR coagulated with acid and flocculant (AF-SPNR) would obstruct both gel formation and storage hardening.

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Characterisation of macrogel composition from industrial natural rubber samples: Influence of proteins on the macrogel crosslink density

Cited by 27 publications

References 32 publications

Melt Rheological Behavior and Morphology of Poly(ethylene oxide)/Natural Rubber-graft-Poly(methyl methacrylate) Blends

Melt Rheological Behavior and Morphology of Poly(ethylene oxide)/Natural Rubber-graft-Poly(methyl methacrylate) Blends

Variation of technological properties of field natural rubber lattices from Hevea brasiliensis clones and natural rubber-based compounds

Impact of non-rubber components on the branching structure and the accelerated storage hardening in Hevea rubber

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