Article
Chemistry, Physical
Xue Liang, Xiaojie Li, Yong Tang, Xiyu Zhang, Wei Wei, Xiaoya Liu
Summary: In this study, graphene oxide (GO) sheets were covalently linked with hyperbranched epoxy resin to enhance the properties of epoxy composites. The functionalized GO sheets showed better dispersion and interfacial compatibility, leading to significant improvements in mechanical and thermal properties. The results suggest that the functionalized composite is a promising, all-purpose modifier for epoxy resins.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Yuanbo Zhang, Hongxia Yan, Ruizhi Yu, Junshan Yuan, Kaiming Yang, Rui Liu, Yanyun He, Weixu Feng, Wei Tian
Summary: A new strategy of using hyperbranched dynamic crosslinking networks (HDCNs) to convert petroleum-based thermosets into degradable, reconfigurable, and multifunctional vitrimers has been proposed. HDCNs possess solvent adaptation and reversible behavior, enabling degradation and reconstruction at room temperature. The resulting vitrimers exhibit superior properties compared to the original thermosets.
Article
Agricultural Engineering
Xiang Zhen, Zhongbin Xu, Huiwen Li, Jin Xu, Shunni Zhu, Zhongming Wang
Summary: Lignin-based epoxy resins with tunable thermomechanical properties were prepared through constructing a partially ordered crosslinking network. It was found that the introduction of lignin-based epoxy resin can significantly reduce the activation energy of curing reaction, indicating higher reactivity. The epoxy resins exhibited improved flexural strength, impact toughness, storage modulus, and glass transition temperature with the increase in lignin content. Moreover, the incorporation of lignin decreased the initial degradation temperature of epoxy resins, while improving Td50%, Tmax, and char yield.
INDUSTRIAL CROPS AND PRODUCTS
(2023)
Article
Polymer Science
Tianyu Zhu, Chunxiang Lu, Xiaoxuan Lu, Jieying Zhi, Yingjun Song
Summary: A new epoxy-terminated hyperbranched polyether sulfone (EHPES) was synthesized and modified in diglycidyl ether of bisphenol-A (DGEBA), improving the comprehensive performance of the copolymer, especially the tensile, flexural, and impact strengths.
Article
Chemistry, Multidisciplinary
Laihui Xiao, Wenbin Li, Shuai Li, Jie Chen, Yigang Wang, Jinrui Huang, Xiaoan Nie
Summary: A method to prepare hyperbranched epoxies (HBEPs) with different molecular weights was proposed in this study, which showed superior mechanical properties and toughness after curing compared to commercial DGEBA thermosets. HBEP with the highest molecular weight and degree of branching demonstrated the best comprehensive mechanical properties.
Article
Polymer Science
I Lorero, A. Rodriguez, M. Campo, S. G. Prolongo
Summary: In this work, epoxy/amine resins with different Diels-Alder crosslinking ratios were manufactured, providing a simplified route that enhances sustainability and industrial transferability. The effect of curing temperatures and Diels-Alder crosslinking on the mechanical properties was studied, leading to the identification of an optimal crosslinking ratio that balances recyclability and mechanical properties. The feasibility of monitoring the network reversibility and evolution was demonstrated through DMTA and microhardness analysis.
Article
Polymer Science
Qiu Shi, Siqi Huo, Cheng Wang, Guofeng Ye, Lingfeng Yu, Zhengping Fang, Hao Wang, Zhitian Liu
Summary: The implementation of current flame-retardant strategy often leads to the deterioration of other properties. In this study, a flame-retardant hyperbranched polymer was synthesized and applied to epoxy resin. The results show that this hyperbranched polymer improves the transparency, glass-transition temperature, and UV-blocking properties of epoxy resin, while also enhancing its toughness and strength. Additionally, incorporating this hyperbranched polymer significantly enhances the fire safety performance of epoxy resin.
POLYMER DEGRADATION AND STABILITY
(2022)
Article
Chemistry, Multidisciplinary
Yanxin Hao, Liuyue Zhong, Tingcheng Li, Junheng Zhang, Daohong Zhang
Summary: An efficient strategy utilizing disulfide and imine dynamic covalent bonds in a vanillin-based hyperbranched epoxy resin is proposed for the development of recyclable biobased materials. The resin demonstrates high glass transition temperature, improved creep resistance, mechanical properties, and exhibits self-healing ability, reprocessability, and degradability. This represents a significant advancement in the design of high-performance epoxy covalent adaptable networks.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Siqi Huo, Ting Sai, Shiya Ran, Zhenghong Guo, Zhengping Fang, Pingan Song, Hao Wang
Summary: This study presents an effective method to create transparent epoxy thermosets with outstanding mechanical, dielectric, and fire-retardant properties by incorporating a P/N/B-containing hyperbranched oligomer. The addition of the hyperbranched additive improves the glass-transition temperature, optical transmittance, mechanical strength, and toughness of the epoxy resin, while reducing the dielectric constant, loss, heat release, and smoke generation during combustion. These findings have significant implications for the development of high-performance flame-retardant epoxy resins.
COMPOSITES PART B-ENGINEERING
(2022)
Article
Polymer Science
Jingyuan Hu, Liyue Zhang, Mingxuan Chen, Jinyue Dai, Na Teng, Hongchi Zhao, Xinwu Ba, Xiaoqing Liu
Summary: In order to improve the fire safety and mechanical properties of epoxy resins, researchers synthesized three epoxy-terminated hyperbranched flame retardants (EHBFRs) with different branches. These EHBFRs were added to the diglycidyl ether of bisphenol A (DGEBA) and cured with 4, 4-diaminodiphenylmethane (DDM). The results showed that the EHBFRs greatly enhanced the fire safety of the cured resins and improved their mechanical properties.
Article
Polymer Science
Andrzej Puszka, Marcin Knec, Wojciech Franus, Beata Podkoscielna
Summary: The synthesis, characterization, and properties of polymeric composites were investigated. The composites were prepared using commercially available epoxy resin cross-linked with triethylenetetramine. Natural fillers in the form of minerals were added to improve the thermal and mechanical properties. The structures were confirmed using infrared spectroscopy, and the thermal properties were studied through calorimetry and dynamic-mechanical analysis. Hardness and strength tests were also conducted.
Article
Materials Science, Composites
Zhongzhou Zhang, Qichen Yin, Yuhong Liu
Summary: Despite its many merits, the practical application of epoxy (EP) is significantly hindered by its intrinsic flammability. Intercalation-functionalized graphene oxide (GO) has shown excellent performance in flame retardancy studies, but the effect of layer spacing on the flame retardant performance of polymers is still lacking. Three GO flame retardants with different layer spacing were prepared and evaluated for flame retarding EP composites. The results showed that the layer spacing of GO significantly affects the flame retardancy of the composite by influencing the formation of a protective char layer.
POLYMER COMPOSITES
(2023)
Article
Polymer Science
Beata Podkoscielna, Monika Wawrzkiewicz, Lukasz Klapiszewski
Summary: This study addresses water pollution caused by toxic substances, such as azo dyes, by synthesizing and characterizing new polymeric sorbents for the removal of the toxic azo dye C.I. Acid Violet 1 (AV1). The results indicate that the obtained sorbents have good adsorption capacities for AV1, providing a potential solution for environmental remediation.
Article
Engineering, Environmental
Huawei Qiao, Mingfeng Chen, Bing Chen, Huagui Zhang, Botuo Zheng
Summary: This study systematically reveals the role of a hyperbranched polysiloxane (PBPS) with boron in the curing kinetics of epoxy resin. Boron efficiently reduces the induction time of curing and increases the reaction rate in the non-catalytic stage. The addition of PBPS also affects the activation energy of the viscous flow stage, resulting in excellent toughening effects. This study fills the knowledge gap regarding the mechanism and influence of hyperbranched polysiloxane in the curing of epoxy resin.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Multidisciplinary
Guofeng Ye, Siqi Huo, Cheng Wang, Qiu Shi, Lingfeng Yu, Zhitian Liu, Zhengping Fang, Hao Wang
Summary: The study presents a novel epoxy resin based on TP, which has a high oxygen index and fire rating, reduces smoke production, improves the mechanical properties and transparency of the epoxy resin.
COMPOSITES PART B-ENGINEERING
(2021)
Article
Polymer Science
J. Casado, O. Konuray, A. Roig, X. Fernandez-Francos, X. Ramis
Summary: Polymer networks with dynamic bonds, known as covalent adaptable networks (CANs), combine the mechanical properties and chemical resistance of thermosets with the ability to be reprocessed. In this study, a thermoset material with high concentration of dynamic bonds was designed to facilitate repair and recycle at feasible temperatures. The material was partially cured through UV light and further improved by a thermal treatment. The effect of thermal post-treatment and catalyst choice on the material's properties was investigated, showing that transesterification reactions increased the overall crosslinking density. The material demonstrated the ability to be fully repaired and recycled due to the presence of dynamic bonds.
EUROPEAN POLYMER JOURNAL
(2022)
Article
Polymer Science
Licheng Liu, Haijun Dong, Yingfeng Yu, Zhengming Tang, Chenyan Bai, Yanli Feng, Hongyu Chen, Thorsten Schmidt
Summary: A new microcapsule thermolatent catalyst was prepared using the emulsion solvent evaporation method. By changing the composition of the polymeric shell, the latency and catalytic activity of the catalyst could be controlled. Compared to traditional thermolatent catalysts, the microcapsule catalyst showed better latency and activity.
Article
Polymer Science
Federico Guerrero, Silvia De la Flor, Xavier Ramis, Jose-Ignacio Santos, Angels Serra
Summary: The present study demonstrates the synthesis of nanocomposites with a polymeric matrix and silsesquioxane-type structures, aiming to combine the advantages of hardness and strength from the inorganic phase and elasticity and toughness from the organic matrix. The incorporation of POSS improved the vitrimeric behavior of the materials by reducing relaxation times and increasing storage moduli. The modified materials showed high transparency and enhanced toughness.
EUROPEAN POLYMER JOURNAL
(2022)
Article
Forestry
Dora Straus, Maria Caballol, Francesc Serrado, Josep Oliveras, Xavier Ramis, Jonas Oliva
Summary: The decline of trees caused by exotic Phytophthora pathogens is a significant problem worldwide. This study found that forests with high recreational use are more susceptible to Phytophthora attack compared to forests with low recreational use in Catalonia. The presence of Phytophthora is associated with defoliation and low regeneration of trees.
FOREST ECOLOGY AND MANAGEMENT
(2023)
Article
Materials Science, Multidisciplinary
B. Pascual-Jose, S. De la Flor, A. Serra, A. Ribes-Greus
Summary: The dielectric spectra of the poly(thiourethane) network, HDI-S3, were analyzed to understand the nature and cooperativity of each observed dielectric process. The Y1, Y2, and fi dielectric relaxations at low temperatures were attributed to noncooperative local motions in the glassy state, with apparent activation energies of 30, 36, and 60 kJ/mol, respectively. At higher temperatures, three dielectric relaxations were observed (alpha Tg, alpha*, p), with alpha Tg being attributed to the glass transition and overlapping with the alpha* relaxation. The molecular origin of the alpha* relaxation was associated with a bond exchange reaction, while the p relaxation was ascribed to sample heterogeneity, although its origin remained uncertain. The DC conductivity (sigma DC) was found to be a suitable variable for analyzing the bond exchange reaction, indicating a molecular exchange mechanism of dissociative nature in HDI-S3.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
David Santiago, Dailyn Guzman, Jesu's Padilla, Pere Verdugo, Silvia De la Flor, Angels Serra
Summary: Epoxy-based vitrimers with high Tg values and a homogeneous network structure were developed as recyclable and reprocessable adhesives for automotive structural applications. The materials showed complete stress relaxation in just 3.6 minutes at 180 degrees C, with the presence of TBD catalyst resulting in the fastest relaxation. They were successfully recycled and reprocessed through alcoholysis and mechanical grinding, and demonstrated high single-lap shear stress values for mono- and multimaterial joints. Overall, this study presents a comprehensive investigation of recyclable and reprocessable epoxy-based vitrimers.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Polymer Science
Osman Konuray, Xavier Fernandez-Francos, Xavier Ramis
Summary: In this work, a model is proposed to reproduce the stress relaxation dynamics of relaxation processes in covalent adaptable networks (CANs) produced by stepwise polymerization. The model captures the elastic response of the material under initial stress by simulating a network decrosslinking process. By using a combination of a recursive structural model and a kinetic model for the bond exchange reaction, the model can predict the stress relaxation profile in different CAN-based materials based on their network structure, bond exchange rate, and presence of permanent bonds. The model's prediction capabilities are validated through simulations of scenarios taken from the literature, demonstrating the flexibility in designing CAN-based materials through tailored network architecture.
Article
Chemistry, Physical
Federica Vitrone, Sascha Brinker, Diego Ramos, Francesc Ferrando, Joan Salvado, Carsten Mai
Summary: This study introduces an innovative method to produce formaldehyde-free Medium Density Fiberboard (MDF). By combining steam exploded Arundo donax L. (STEX-AD) and untreated wood fibers (WF) in different ratios, two series of boards were manufactured and self-bonded using 4 wt% of pMDI. The mechanical and physical properties of the boards were significantly influenced by the material formulation and density, and the boards made solely of STEX-AD showed comparable performance to those made with pMDI.
Article
Polymer Science
Federico Guerrero, Xavier Ramis, Silvia De la Flor, Angels Serra
Summary: A series of poly(thiourethanes) (PTUs) have been synthesized from biobased monomers. Limonene and squalene were transformed into polyfunctional thiols which were then reacted with hexamethylene diisocyanate (HDI) to prepare bio-based poly(thiourethane) vitrimer-like materials. The proportions of the two thiols in the reactive mixture can change the characteristics of the final material. The materials exhibited good self-healing efficiency.
Article
Materials Science, Multidisciplinary
Osman Konuray, Sasan Moradi, Adria Roig, Xavier Fernandez-Francos, Xavier Ramis
Summary: In order for covalent adaptable networks to be fully recyclable, they need to overcome all topological restrictions and flow. A statistically based method showed that the relaxation of stress in disulfide-containing thiol-ene polymers is closely related to the fraction of permanent cross-links. Even with low disulfide content, the materials can be recycled at moderate temperatures without losing tensile properties by triggering transesterification reactions through increased reprocessing temperature, due to the presence of ester bonds.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Gang Wang, Zhengxiang Zhou, Mengyu Chen, Juanjuan Wang, Yingfeng Yu
Summary: In this study, a facile method to improve the processability and performance of ultraviolet (UV) curable acrylate-based pressure-sensitive adhesives (PSAs) was demonstrated by introducing a low-vinyl-equivalent and high-viscosity polyurethane acrylate (PUA) prepolymer. The chemical cross-linking-induced enhancement of the haze values of PUA-based PSAs was investigated for the first time. Moreover, using poly(PUA-2EHA) as the optically clear adhesive resulted in an improved and uniform bright image display without blemish.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Polymer Science
Adria Roig, Marco Agizza, Angels Serra, Silvia De la Flor
Summary: This study synthesized bio-based disulfide vitrimers through an epoxy-amine polycondensation process and characterized them using FTIR, TGA, and thermomechanical analysis. The addition of TREN increased the crosslinking density, resulting in a maximum relaxation rate at a proportion of 25%. The relaxation times of the vitrimers were decreased by catalyzing the disulfide metathesis and achieving a balance between the proportion of disulfide bonds and the content of nucleophilic tertiary amines.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Polymer Science
Adria Roig, Xavier Ramis, Silvia De la Flor, Angels Serra
Summary: This paper aims to enhance sustainability in the thermosetting polymeric field through the use of bio-based monomers and environmentally friendly processing technologies based on dual-curing. By transforming eugenol into acrylate epoxy eugenol (AEEU), which can take part in thio-Michael additions and thiol-epoxy reactions, the authors have developed a sequential dual-curing process. The addition of a basic catalyst helps facilitate the curing process. Through the selection of three thiols, including one derived from eugenol and others derived from pentaerythritol, the authors have demonstrated the ability to tailor and improve the intermediate material characteristics in the dual-curing process. Rheology, DSC, and FTIR were used to evaluate the curing steps, while TGA and DMTA were employed to assess the thermal characteristics of intermediate and final materials. Tensile tests were performed to evaluate the mechanical properties.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
Zhengxiang Zhou, Gebin Shen, Xinrong Huang, Chuanhui Yang, Yingfeng Yu
Summary: In this study, a series of polyimides and polyimide-b-polysiloxane copolymers were fabricated to minimize the internal stress between the polymer and substrates. The results showed that the internal stress decreased significantly with the copolymerization of polyimides and polysiloxanes, and the copolymer had a similar coefficient of thermal expansion to copper.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Polymer Science
Yuanzhang Jiang, Xuyi Wang, Yanting Han, Dakai Gong, Yingchun Gu, Lin Tan
Summary: In this study, FeCl3 and poly(acrylic acid) (PAA) were doped into waterborne polyurethanes (WPUs) to create multifunctional materials with self-healing and antimicrobial properties. WPU/Fe/PAA-5.5, containing 5.5 wt % PAA, exhibited excellent mechanical properties, strong self-healing capabilities, and an impressive antimicrobial rate of over 90%. These supramolecular films were also highly recyclable through hot-pressing.
Article
Polymer Science
Longyu Tian, Min Wang, Guangming Liao, Baoliang Liu, Sujuan Zhang, Yucheng Sun, Zhen Meng, Jintao Zhang, Zaijun Lu
Summary: Two kinds of benzoxazine monomers were synthesized and used to prepare polybenzoxazine anion exchange membranes (AEMs) with quaternary ammonium functionalization. The LQPBZ AEM exhibited better ion conductivity and alkaline stability.
Article
Polymer Science
Claire A. Lemarchand
Summary: This study investigates the shock behavior of three different polymers through molecular dynamics simulations. The results reveal specificities in the shock behavior of polymers, including deviations from the linear relation between shock velocity and particle velocity, as well as differences in shear stress relaxation behind the shock front. It is found that the deviation of the Hugoniot locus is related to the change in the relative contribution of bonding and non-bonding potential energies, while polymers with higher glass transition temperatures exhibit slower shear stress relaxation.
Article
Polymer Science
Zengquan Liu, Xiaochun Yin, He Zhang, Shuo Gao, Qinglin Kuang, Yanhong Feng
Summary: A powder solid-state extension (PSSE) technology was proposed to address the high melt viscosity issue of UHMWPE. By uniaxial extension and sintering in the solid state, a highly self-reinforced material was prepared. X-ray diffraction and scattering techniques were used to study the structural evolution during the PSSE process, and a solid-phase induced transformation model was established.
Article
Polymer Science
Zhike Li, Anyu Luo, Rui Zhou, Xin Li, Haiyan Li
Summary: A novel high temperature resistance IL@SiO2 nanocapsules were successfully prepared and their friction and wear properties in PA6 composites were studied. The addition of IL@SiO2 nanocapsules reduced the friction coefficient and wear rate without affecting the mechanical properties of PA6. The synergy between the IL core and SiO2 wall in the nanocapsules improved the self-lubricating performance of the PA6 composites.
Article
Polymer Science
Xin Liu, Xuhong Guo, Qi Liao
Summary: In this study, an algorithm for accurately estimating viscosity is developed using molecular dynamics simulations and the Green-Kubo formula. This algorithm can be applied to complex systems with long correlations, such as macromolecular and biological simulation systems.
Article
Polymer Science
Hao Pu, Yun-Lei Hou, Jing -Zhou Chen, Dong -Lin Zhao
Summary: The use of modified graphene improves the interfacial adherence of carbon fibers to epoxy resin, resulting in enhanced interfacial and bending properties of CF and matrix in CF/EP composites, as well as increased interlaminar shear strength and flexural strength.
Article
Polymer Science
Wei-Chung Ke, Jin-Wei Lin, Manohar Reddy Busireddy, Yueh-Hsing Lee, Jiun-Tai Chen, Chain-Shu Hsu
Summary: This study introduces a crosslinkable monomer, TAIC, to synthesize three crosslinked polyimide films, which exhibit improved thermal, mechanical, and dielectric properties. The introduction of TAIC enhances the tensile strength, reduces the dielectric constant and dielectric loss, and decreases the coefficient of thermal expansion of the polyimide films.
Article
Polymer Science
Alex Kwasi Kumi, Ruiling Fan, Ye Chen, Yumei Zhang
Summary: The difference in leaching of amylopectin from cellulose/amylopectin/1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) blends during regeneration in water and aqueous ethanol has been studied. Molecular dynamics simulations showed that the dissolution and regeneration mechanisms of amylopectin in [Bmim][Cl] are similar to cellulose in ionic liquids. Water regeneration leads to weak electrostatic interactions, resulting in high leaching of amylopectin. In contrast, ethanol-water interactions enhance electrostatic interactions among amylopectin chains, limiting amylopectin leaching in aqueous ethanol.
Article
Polymer Science
Xi Zeng, Junwei Zhou, Junbiao Peng, Chunsheng Zhang, Danling Wang, Yihu Song, Qiang Zheng
Summary: This study utilizes an oligomer deep eutectic solvent (DES) based on polyethylene glycol to regulate the vulcanization kinetics of rubber. The results show that the DES can accelerate vulcanization at low temperatures without affecting the crosslinking density and Mullins effect.
Article
Polymer Science
Qianqian Yue, Yongfei Peng, Xingjian Liu, Aihua He, Huarong Nie
Summary: The addition of metal deactivators can effectively suppress the aging of TBIR, prolong its lifespan, and have no negative effects on its physical and processing properties. These research findings are of great importance for improving the stability and aging resistance of polymers.
Article
Polymer Science
J. Gomez-Caturla, J. Ivorra-Martinez, R. Tejada-Oliveros, V Moreno, D. Garcia-Garcia, R. Balart
Summary: This work focuses on the development of environmentally friendly PLA formulations by using different esters derived from geraniol as plasticizers. The results show that these esters have good compatibility with PLA, and they can effectively enhance the elongation and plasticity of PLA, reduce its glass transition temperature, and slightly improve its water absorption capabilities.
Article
Polymer Science
Dandan Li, Zhaohui Lu, Zhao Ke, Ke Xu, Fengna Dai, Youhai Yu, Guangtao Qian, Chunhai Chen
Summary: In this study, cross-linked PI aerogel membranes with low dielectric constant and high moisture resistance were prepared by co-polymerization and scraping coating technology. The incorporation of fluorinated blocks and benzimidazole ring structures resulted in novel PI aerogel membranes with fascinating dielectric properties and outstanding moisture resistance.
Article
Polymer Science
Zhaoyang Chu, Qing Zhang, Haihua Luo, Han Zhou, Fapei Zhang, Wei Chen, Wenhua Zhang
Summary: Multi-physical fields solution processing strategy is a universal and facile method for preparing various conjugated polymer films and high-performance devices. In this study, we employed a combined microfluidic flow and ultrasonication strategy (FU) for processing CP solutions, and found a pronounced synergetic effect in promoting the pre-ordering of chains in solution. The conformation order and anisotropy of the solution were revealed through various characterizations. A non-classical nucleation model for polymer crystallization in non-equilibrium solution processing was confirmed. The roles of microfluidic flow and ultrasonication in chain aggregation and crystallization were addressed through multi-physical simulations. Compared to pristine solutions, the FU strategy showed improved solution anisotropy and crystallization kinetics, resulting in higher crystallinity in films and increased mobilities in OFET devices. The FU processing strategy provides a universal approach for regulating chain conformation and aggregation in conjugated polymer solutions.
