Article
Polymer Science
Nabil Hayeemasae, Sitisaiyidah Saiwari, Siriwat Soontaranon, Abdulhakim Masa
Summary: NRL, a natural polymer extracted from para rubber trees, contains proteins that may cause allergies. This study examines the differences in properties between NRL and DPNR, and finds that proteins, phospholipids, and chain entanglements contribute to the formation of natural polymer networks in NR.
Article
Polymer Science
Supinya Nijpanich, Adun Nimpaiboon, Porntip Rojruthai, Jae-Hyeok Park, Takeshi Hagio, Ryoichi Ichino, Jitladda Sakdapipanich
Summary: In this study, the photochemical degradation method was used to modify the properties of natural rubber. TiO2-coated hollow glass beads (TiO2-HGBs) were introduced as photocatalysts to functionalize deproteinized natural rubber (DPNR). The molecular weight of DPNR was significantly reduced and functional groups were successfully incorporated. Remarkably, TiO2-HGBs maintained their performance after multiple cycles of reuse, showing great potential for the advanced functionalization of natural rubber.
Article
Polymer Science
Apisara Sillapasuwan, Phattharawadi Saekhow, Porntip Rojruthai, Jitladda Sakdapipanich
Summary: Hydroxyl-terminated natural rubber (HTNR) is a versatile product that can be produced using photochemical degradation with a TiO2 film. Coating a quartz substrate with the TiO2 film significantly enhances the photochemical activity and photocatalytic efficiency.
Article
Pharmacology & Pharmacy
Wiwat Pichayakorn, Pattwat Maneewattanapinyo, Chaowalit Monton, Nattakan Dangmanee, Jirapornchai Suksaeree
Summary: The study demonstrated the use of natural rubber for topical drug delivery and successfully fabricated a porous film loaded with silver nanoparticles. It was discovered that the silver nanoparticles could easily enter the film and exhibited potent antibacterial activity when released.
Article
Polymer Science
Thuong Thi Nghiem, Nurul Hayati Yusof, Seiichi Kawahara
Summary: Our research aimed to investigate the morphology and properties of natural rubber (NR) dispersed in a polystyrene/silica hybrid nanomatrix. The hybrid nanomatrix structure was formed by graft copolymerization, resulting in outstanding mechanical and viscoelastic properties. The tensile strength and storage modulus of NR with the hybrid nanomatrix structure were significantly higher than those of the silica nanomatrix, attributed to the formation of the hybrid nanomatrix structure.
Article
Polymer Science
Supharat Inphonlek, Namthip Bureewong, Kasama Jarukumjorn, Pranee Chumsamrong, Chaiwat Ruksakulpiwat, Yupaporn Ruksakulpiwat
Summary: This study successfully achieved graft copolymerization of poly(acrylic acid-co-acrylamide) onto deproteinized natural rubber, which enhanced the polarity of natural rubber and improved its compatibility with silica. The mixture of (PAA-co-PAM)-DPNR and silica improved the mechanical properties of DPNR.
Article
Materials Science, Characterization & Testing
Takayuki Saito, Masaki Yamano, Kazumi Nakayama, Seiichi Kawahara
Summary: Rubber-state nuclear magnetic resonance (NMR) spectroscopy was used to quantitatively analyze crosslinking junctions and uncrosslinked pendant sulfidic groups in natural rubber (NR) vulcanizates with two different formulations. The resulting NR vulcanizates were characterized to determine crosslink density, number of sulfur atoms at crosslinking junctions, and structure of crosslinking junctions. Signals in rubber-state C-13 and H-1 NMR spectra were assigned to specific groups using two-dimensional NMR spectroscopy, allowing for estimation of the proportion of CH linking to sulfur at the crosslinking junctions.
Article
Engineering, Chemical
Lam Ba Nguyen, Hoang Van Nguyen, Cuong Quoc Vu, Ha Hong Cao, Anh Van Nguyen, Seiichi Kawahara, Thuong Thi Nghiem
Summary: This study investigated the self-healing performance of epoxidized deproteinized natural rubber (EDPNR) and EDPNR/graphene oxide (GO) composites. It was found that the recovery of tensile strength was higher for EDPNR25/GO0.5 and EDPNR25/GO1.0 composites compared to EDPNR50/GO0.5 and EDPNR50/GO1.0 composites. The interdiffusion of epoxidized natural rubber molecules was identified as the key factor affecting the self-healing performance rather than the hydrogen bonds between GO and functional groups on EDPNR molecules.
POLYMER ENGINEERING AND SCIENCE
(2023)
Article
Engineering, Environmental
Jirapornchai Suksaeree, Rungtiwa Waiprib, Wiwat Pichayakorn
Summary: This study developed lidocaine transdermal patches composed of deproteinized natural rubber latex, gelatinized starch, and glycerin. Adding starch increased the hydrophilic properties of the blended films, improving swelling, erosion, and moisture uptake. Storage at 4 degrees Celsius was found to be the most suitable condition for film storage.
JOURNAL OF POLYMERS AND THE ENVIRONMENT
(2022)
Article
Polymer Science
Masaki Yamano, Yoshimasa Yamamoto, Takayuki Saito, Seiichi Kawahara
Summary: The vulcanized natural rubber prepared at 130 degrees Celsius exhibited superior mechanical properties due to high stereoregularity and rapid strain-induced crystallization after vulcanization.
Article
Polymer Science
Zhenhui Yang, Yizhong Yuan, Xiaohui Tian, Jinyu Sun, Jie Jin
Summary: In this study, water swellable rubber DPP was synthesized by emulsion polymerization using DPNR as the substrate, AM and St as the monomers, and Brij-35 as the emulsifier. The successful grafting of AM and St was confirmed by various analysis methods. The effects of blending with different amounts of BT on the mechanical and water absorption properties were investigated. The prepared DPP and DPP/BT show great potential for a wide range of applications.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Polymer Science
Supharat Inphonlek, Kasama Jarukumjorn, Pranee Chumsamrong, Chaiwat Ruksakulpiwat, Yupaporn Ruksakulpiwat
Summary: In this work, crosslinked poly(acrylic acid-co-acrylamide)-grafted deproteinized natural rubber/silica composites were prepared and used as coating materials for fertilizer. The addition of silica improved the mechanical properties of the composites. The crosslinked (PAA-co-PAM)-DPNR/silica composites as outer layers had the ability to retain water and delay the release of fertilizer. These composites have potential for controlled release and water retention in agricultural applications.
Article
Chemistry, Medicinal
Manjuan Liu, Amin Mirza, P. Craig McAndrew, Arjun Thapaliya, Olivier A. Pierrat, Mark Stubbs, Tamas Hahner, Nicola E. A. Chessum, Paolo Innocenti, John Caldwell, Matthew D. Cheeseman, Benjamin R. Bellenie, Rob L. M. van Montfort, Gary K. Newton, Rosemary Burke, Ian Collins, Swen Hoelder
Summary: Here, we present a reproducible, accurate, and versatile quantitative ligand-observed NMR assay that can determine K(d) values of fragments in the affinity range of low μM to low mM using the transverse relaxation rate R(2) as the observable parameter. We designed an assay format with automated sample preparation and simplified data analysis, and demonstrated its reproducibility, accuracy, and detection limits using tool compounds. Furthermore, we used this assay to triage fragment hits against the CRBN/DDB1 complex.
JOURNAL OF MEDICINAL CHEMISTRY
(2023)
Article
Polymer Science
Saki Yokota-Imai, Shinsuke Chida, Takehiro Suzuki, Naoshi Dohmae, Takeshi Gotoh
Summary: This study investigated the microstructure and protein composition of solid rubber from Ficus carica. It was found that the nonrubber components formed a nonuniform framework in the rubber matrix, and many rubber particles were fused together. The major protein in Fc rubber was determined to be ficin, a cysteine endoproteolytic protease, which degrades proteins associated with rubber particles rather than connecting the cis-1,4-polyisoprene chains.
POLYMERS FOR ADVANCED TECHNOLOGIES
(2021)
Review
Polymer Science
Seiichi Kawahara
Summary: Natural rubber is a nanocomposite material with an island-nanomatrix structure composed of cis-1,4-polyisoprene particles dispersed in a nanomatrix of proteins and phospholipids. The presence of this structure greatly enhances the mechanical properties of natural rubber. Experimental results demonstrate that the mechanical properties of natural rubber decrease when proteins are removed, but can be recovered when the island-nanomatrix structure reforms.
Article
Polymer Science
Thu Ha Nguyen, Quoc Viet Do, Anh Dung Tran, Seiichi Kawahara
POLYMERS FOR ADVANCED TECHNOLOGIES
(2020)
Article
Polymer Science
Thuong Nghiem, Linh Nguyen, Nghia Phan, Nurul Yusof, Seiichi Kawahara
POLYMERS FOR ADVANCED TECHNOLOGIES
(2020)
Article
Chemistry, Multidisciplinary
Seiichi Kawahara, Asangi Gannoruwa, Ken Nakajima, Xiaobin Liang, Isamu Akiba, Yoshimasa Yamamoto
ADVANCED FUNCTIONAL MATERIALS
(2020)
Article
Polymer Science
N. T. Thuong, N. P. D. Linh, C. H. Ha, P. T. Nghia, S. Kawahara
RUBBER CHEMISTRY AND TECHNOLOGY
(2020)
Article
Chemistry, Multidisciplinary
Hoang V. Tran, Nghia D. Nguyen, Chinh T. Q. Tran, Luyen T. Tran, Thu D. Le, Huyen T. T. Tran, B. Piro, Chinh D. Huynh, Thinh N. Nguyen, Nga T. T. Nguyen, Hue T. M. Dang, Huy L. Nguyen, Lam D. Tran, Nghia T. Phan
ARABIAN JOURNAL OF CHEMISTRY
(2020)
Article
Materials Science, Multidisciplinary
Nguyen Thu Ha, Cao Hong Ha, Le Viet Hung, Nguyen Pham Duy Linh, Tran Thi Thuy, Phan Trung Nghia, Seiichi Kawahara, Toshiaki Ougizawa
MATERIALS TRANSACTIONS
(2020)
Article
Biotechnology & Applied Microbiology
Lan Huong Nguyen, Hoang Dung Nguyen, P. Thao Tran, Thi Thuong Nghiem, Thi Thanh Nguyen, Viet Linh Dao, Trung Nghia Phan, Anh Kim To, Masashi Hatamoto, Takashi Yamaguchi, Daisuke Kasai, Masao Fukuda
Article
Chemistry, Multidisciplinary
Quentin Tevenot, Seiichi Kawahara
Summary: In this study, ATRP-ARGET was used to graft polymerization of styrene onto natural rubber in the latex stage as a heterogeneous system. The particles were characterized by H-1 NMR spectroscopy and SEC, confirming the success of graft copolymerization. The resulting grafted polystyrene exhibited living radical behavior, showing a linear evolution of molecular weight versus monomer conversion and a high grafting efficiency with a narrow molecular weight distribution.
Article
Materials Science, Composites
Trinh Thi Hang, I. Putu Mahendra, Tran Manh Thang, Seiichi Kawahara, Phan Trung Nghia
Summary: The study found that the temperature glass of EDPNR shifted to the right with an increase in lithium salt content in the ternary blends, while the ionic conductivity reached its peak at 35 wt.% and decreased significantly afterwards. In the EDPNR/PMMA blend with an 80/20 ratio, the highest ionic conductivity was observed. Results also demonstrated a close correlation between the temperature glass and conductivity behavior of EDPNR.
PROGRESS IN RUBBER PLASTICS AND RECYCLING TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Seiichi Kawahara, Hironari Nishioka, Masaki Yamano, Yoshimasa Yamamoto
Summary: The preparation of synthetic rubber with mechanical properties identical to natural rubber has been achieved by forming an island-nanomatrix structure in the synthetic rubber.
ACS APPLIED POLYMER MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Nguyen Thu Ha, Vu Huy Hien, Nguyen Hai Nam, Phan Trung Nghia, Toshiaki Ougizawa, Seiichi Kawahara
Summary: This study successfully prepared an electrically conductive membrane based on natural rubber through graft-copolymerization of aniline and epoxidation in latex stage. Structural characterization confirmed the successful introduction of polyaniline and epoxy group to natural rubber chain. The obtained EDPNR-g-PAni showed higher tensile strength, thermal resistance and significantly improved electrical conductivity compared to raw natural rubber.
VIETNAM JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
I. P. Mahendra, Mai K. Linh, Nguyen N. Thang, Vu T. Thuy, Le T. Trang, Le X. Thinh, Nguyen T. H. Phuong, Nguyen T. Ha, Nghiem T. Thuong, Seiichi Kawahara, Yoshimasa Yamamoto, Phan T. Nghia
Summary: The study successfully removed protein from natural rubber latex using magnetic coated alumina (Fe3O4@Al2O3), demonstrating the effectiveness of this method and identifying the optimal operating conditions.
JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
(2021)
Article
Polymer Science
I. Putu Mahendra, Phan Trung Nghia, Nguyen Thi Hong Phuong, Tring Thi Hang, Nur Fazreen Alias, Hanafi Ismail
Summary: PLLA-g-LMWNR was used as a compatibilizer for PLLA/DPNR blend, significantly improving the mechanical properties of the blend containing 3 wt % PLLA-g-LMWNR. Scanning electron microscopy revealed a decrease in pore diameter from 5.44 to 1.56 μm, while thermal analysis showed a shift in T-g value of the PLLA phase from 63.1 to 61.4 degrees C. These results confirm the enhanced compatibility of PLLA/DPNR blend with PLLA-g-LMWNR.
Article
Polymer Science
Tetsu Sato, Mariko Takahashi, Takeshi Saito, Masahito Toyonaga, Itsuo Tanuma, Rie Yamada, Satoru Hosoda
Summary: An automatic evaluation system for photooxidation has been developed and successfully applied to assess the photo-OIT of LDPE samples containing photooxidation stabilizers. The system allows independent setting of various measurement conditions and provides detailed information on the photooxidation process.
POLYMER DEGRADATION AND STABILITY
(2024)
Article
Polymer Science
Zongzheng Zuo, Shuxue Zhou
Summary: In this study, three fluoroalkyl trimethoxysilane (FATMS) additives with different chain lengths were incorporated into a two-component polyurethane clearcoat to improve its hydrophobic durability. The coatings modified with FATMS maintained their surface hydrophobicity under various conditions, but quickly lost it when exposed to both UV irradiation and/or high temperature with water. The results suggest that the FATMS route is more suitable for indoor applications at room temperature.
POLYMER DEGRADATION AND STABILITY
(2024)
Article
Polymer Science
Song Li, Feng Zhao, Xueya Wang, Zhihua Liu, Jingze Guo, Yutong Li, Shuangmei Tan, Zhenxiang Xin, Shuai Zhao, Lin Li
Summary: Green flame retardants have garnered attention for their environmental friendliness, but current options fall short in achieving high flame retardancy for flammable polymers and maintaining environmental protection. This study takes a two-pronged approach to address flame retardants and the flame-retardant process. An eco-friendly bio-based synergistic flame retardant (PAU), synthesized using phytic acid (PA) and urea (U), is used to create a flame retardant coating that can be directly applied to any surface shape using polydopamine as an adhesive. The resulting EPS-PAU exhibits excellent flame retardancy, smoke suppression, and light weight while only slightly increasing the density.
POLYMER DEGRADATION AND STABILITY
(2024)
