Discovery of island-nanomatrix structure in natural rubber

Kawahara, Seiichi

doi:10.1038/s41428-023-00797-2

Cited by 10 publications

(5 citation statements)

References 64 publications

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“…Natural rubber is a naturally occurring nanocomposite with an island-nanomatrix structure, which is composed of cis -1,4-polyisoprene particles with an average diameter of ~1 μm dispersed in a nanomatrix (several tens of nanometers thick) of nonrubber components such as proteins and phospholipids. The island-nanomatrix structure is stabilized by physical and chemical pinning with proteins and phospholipids, which is based on the fact that the cis -1,4-polyisoprene of natural rubber is a branched polymer [ 37 ]. A medical glove is a vulcanized natural rubber product where crosslinks must be formed between the polymer chains to provide adequate mechanical resistance for natural rubber latex products [ 38 ].…”

Section: Discussionmentioning

confidence: 99%

Classification of the Crosslink Density Level of Para Rubber Thick Film of Medical Glove by Using Near-Infrared Spectral Data

Jongyingcharoen,

Howimanporn,

Sitorus

et al. 2024

Polymers

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Classification of the crosslink density level of para rubber medical gloves by using near-infrared spectral data combined with machine learning is the first time reported in this paper. The spectra of medical glove samples with different crosslink densities acquired by an ultra-compact portable MicroNIR spectrometer were correlated with their crosslink density levels, which were referencely evaluated by the toluene swell index (TSI). The machine learning protocols used to classify the 3 groups of TSI were specified as less than 80% TSI, 80–88% TSI, and more than 88% TSI. The 80–88% TSI group was the group in which the compounded latex was suitable for medical glove production, which made the glove specification comply with the requirements of customers as indicated by the tensile test. The results show that when comparing the algorithms used for modeling, the linear discriminant analysis (LDA) developed by 2nd derivative spectra with 15 k-best selected wavelengths fairly accurately predicted the class but was most reliable among other algorithms, i.e., artificial neural networks (ANN), support vector machines (SVM), and k-nearest neighbors (kNN), due to higher prediction accuracy, precision, recall, and F1-score of the same value of 0.76 and no overfitting or underfitting prediction. This developed model can be implemented in the glove factory for screening purposes in the production line. However, deep learning modeling should be explored with a larger sample number required for better model performance.

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Section: Discussionmentioning

confidence: 99%

Classification of the Crosslink Density Level of Para Rubber Thick Film of Medical Glove by Using Near-Infrared Spectral Data

Jongyingcharoen,

Howimanporn,

Sitorus

et al. 2024

Polymers

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“…Natural rubber (NR) is a biosynthesized polymer derived from the Brazilian rubber tree, which consists of approximately 94% cis-1,4-polyisoprene and 6% nonrubber components (NRCs). − Due to its superior comprehensive properties, NR is widely used in myriad aspects of daily life. However, most NR products need to be vulcanized to ensure good strength and elasticity, while the conventional vulcanization process usually requires energy-consuming processing steps and the addition of harmful curing agents. − Moreover, the permanent cross-linking network also puts an obstacle to its reprocessing, degradation, as well as the potential functionalization of vulcanized NR products. − In this context, developing a new generation of NR materials with better performance, degradability, and functional designability via more effective and eco-friendly strategies garnered widespread attention.…”

Section: Introductionmentioning

confidence: 99%

“…35−37 Recent research confirmed that the NRCs such as proteins are located at the surface of rubber particles and could form an "islandnanomatrix" segregated structure in the NR membrane, which contributed to the good mechanical properties of the NR membrane. 3 In fact, the abundant reactive functional groups such as amine and carboxyl groups on the surface of rubber particles in latex may provide interactive sites for the incorporated fillers. If the NRC can be leveraged as a bridge to strengthen the interaction between NR and the incorporated polysaccharide, the fabrication of fully bioresourced and vulcanization-free NR materials with good mechanical properties is promising and tantalizing.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Developing fully biosourced NR composites based on the unmodified NR and biomass remains a challenge. In fact, NR as a biosynthesized resource contains some NRC including proteins, lipids, and inorganic ions in addition to the polyisoprene rubber chains. , It is commonly accepted that protein and phosphate lipid are connected at both ends of the rubber chains (by the α-end and ω-end, respectively) and located on the surface of rubber particles. − Recent research confirmed that the NRCs such as proteins are located at the surface of rubber particles and could form an “island-nanomatrix” segregated structure in the NR membrane, which contributed to the good mechanical properties of the NR membrane . In fact, the abundant reactive functional groups such as amine and carboxyl groups on the surface of rubber particles in latex may provide interactive sites for the incorporated fillers.…”

Section: Introductionmentioning

confidence: 99%

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Fully Biosourced, Vulcanization-Free, and Thermal-Responsive Natural Rubber Material

Huang,

Zhang,

Kong

et al. 2024

Macromolecules

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Natural rubber (NR) material is indispensable in various fields of our daily life, while its preparation usually involves toxic cross-linking agents and energy-consuming vulcanization processes. The permanent cross-linking network of NR products also makes its degradation and recycling difficult. Herein, a fully biosourced, vulcanization-free NR material is developed by simply introducing carrageenan (KC) in the rubber matrix via a facile aqueous mixing method. The nonrubber components (NRCs) on the rubber latex particles are of crucial importance for this art as they can interact with KC by forming hydrogen bonding between the functional groups of proteins in NRCs and the abundant hydroxyl and sulfonate groups on KC molecules. As a result, KC is selectively dispersed between the latex particles and forms a segregated filler network. The special KC network and the good interfacial interaction between KC and rubber promote strain-induced crystallization and endow rubber composites with great mechanical properties. Moreover, the obtained NR/KC composites exhibit an interesting thermalresponsive attraction behavior, which has good potential in smart applications, such as artificial muscle. This work paves a simple and effective path to vulcanization-free NR by leveraging the inherent NRC on latex rubber particles, opening a new horizon for the sustainable development of NR/polysaccharide composite elastomers.

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“…Therefore, new approaches have been introduced to process NR into eco-friendly commercial products [ 6 – 7 ]. Since the discovery of the island nanomatrix structure of NR [ 8 ] and the development of effective methods to prepare deproteinized natural rubber (DPNR) [ 9 – 10 ], graft copolymerization of NR has had significant impacts on improving the mechanical properties of NR. Numerous studies have utilized suitable monomers to graft onto NR via radical routes.…”

Section: Introductionmentioning

confidence: 99%

Modification of graphene oxide and its effect on properties of natural rubber/graphene oxide nanocomposites

Thuong,

Quang,

Cuong

et al. 2024

Beilstein J. Nanotechnol.

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Modification of graphene oxide (GO) by vinyltriethoxysilane (VTES) was investigated to study the effect of silanized GO on radical graft copolymerization of GO onto deproteinized natural rubber (DPNR). The modified GO, GO-VTES (a and b), was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, contact angle, thermal gravimetric analysis, and scanning electron microscopy. The XRD results showed the appearance of an amorphous region of silica particles at a diffraction angle of 22°. The formation of silica was investigated by 29Si NMR, and it was found that the hydrolysis and condensation of VTES proceed more completely in basic conditions than in acidic conditions. The silica content of GO-VTES(b) was 43%, which is higher than that of GO-VTES(a) (8%). Morphology of silica was observed by SEM. The DPNR/GO-VTES nanocomposites prepared with the same amount of GO, GO-VTES(a), and GO-VTES(b) were characterized with tensile tests and dynamic mechanical tests. The stress at break of DPNR/GO-VTES(a) and DPNR/GO-VTES(b) was 5.2 MPa and 4.3 MPa, respectively, which were lower than that of DPNR/GO. However, it exhibited higher stress at small strains and higher storage modulus than DPNR/GO.

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Discovery of island-nanomatrix structure in natural rubber

Cited by 10 publications

References 64 publications

Classification of the Crosslink Density Level of Para Rubber Thick Film of Medical Glove by Using Near-Infrared Spectral Data

Classification of the Crosslink Density Level of Para Rubber Thick Film of Medical Glove by Using Near-Infrared Spectral Data

Fully Biosourced, Vulcanization-Free, and Thermal-Responsive Natural Rubber Material

Modification of graphene oxide and its effect on properties of natural rubber/graphene oxide nanocomposites

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