Article
Polymer Science
Wen Luo, Jiping Wang, Yaqian Guo, Wenbing Hu
Summary: Our study focused on the competition among stress relaxation, strain rates, and temperatures in the polymer crystallization process under different conditions. We found that stress relaxation, limited by fast stretching, plays a dominant kinetic role in slowing down crystallization, similar to the effect of high strain rate. Enhanced stress relaxation during post-growth polymer crystallization influences the final crystallinity and crystal morphology achieved.
Article
Polymer Science
Noelle Billon
Summary: Conventional biaxial testing and free stretch blow molding (ISBM) of preforms were conducted to analyze the biaxial behavior of PET and strain-induced crystallization (SIC) under biaxial conditions. Stretch blowing promoted complex loading paths, allowing for local analysis using marked preforms. The time-temperature superposition principle applied up to high strain in biaxial conditions, facilitating experimental sets and mechanical comparisons. X-ray diffraction analyzed the crystal microstructure and texture, showing that the texture in ISBM is not a simple image of the final deformation state.
Article
Polymer Science
Vito Speranza, Sara Liparoti, Roberto Pantani, Giuseppe Titomanlio
Summary: Understanding the mechanisms that determine mechanical performances during micro-injection molding is crucial for meeting the demand for advanced plastic products. The ability to correctly predict morphology opens the possibility to forecast final part properties. The morphology of semi-crystalline polymers parts mainly consists of spherulites and fibrils, with the thermomechanical history experienced by polymer chains playing a key role.
Article
Chemistry, Multidisciplinary
Jinfu Xing, Bujin Liu, Tuanhui Jiang, Yujing You, Xiangbu Zeng, Jinkui Yang, Chun Zhang, Wei Gong, Li He
Summary: The process of nucleation and growth of polypropylene foam was observed using visualizations of MOFIM and FREEF. The fitting of a mathematical model formula supplemented the judgment conditions of secondary bubbles and explored the generation process and formation conditions. Results showed that secondary bubbles started appearing in the late stage of balanced-foaming and were formed through the combined action of several nucleation mechanisms. The formation of secondary bubbles was closely related to temperature and pressure drop.
Article
Polymer Science
Sara Liparoti, Vito Speranza, Roberto Pantani, Giuseppe Titomanlio
Summary: The possibility of enhancing sustainability through tailoring key surface properties in the injection molding process is intriguing, but challenging due to the presence of micro and nanostructures, which requires a multiscale simulation approach.
Article
Polymer Science
Kristjan Krebelj, Anton Krebelj, Miroslav Halilovic, Nikolaj Mole
Summary: This study investigates crystallization modeling of high-density polyethylene using the open-source code OpenFOAM, incorporating various physical interdependencies such as deformable cavity, pressure-dependent heat transfer coefficient, pressure and crystallinity-dependent thermal conductivity, temperature and crystallinity-dependent specific heat, and latent heat release based on crystallization progress. Through-thickness plots of pressure, temperature, and cooling rate at different levels of crystallinity provide insights into thermomechanical conditions.
Article
Polymer Science
Chidambara Kuttalam Kailasanathan, Salem Thangavel Saravanan, Elango Natarajan, Balasubramaniam Stalin
Summary: The study investigates the reduction in warpage in injection-molded thin-walled components by preparing Polyoxymethylene (POM) composite with various weight fractions of talc. The talc is found to act as a nucleation agent and affect the crystallinity of POM, impacting mechanical properties. The study reveals that POM/1% wt Talc polymer composite shows a 12% reduction in warpage with a 45% increase in impact strength, while POM/3% wt Talc polymer composite exhibits superior mechanical properties but more warpage.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Masayuki Yamaguchi, Wen Shu, Takeyoshi Kimura, Hoang-Giang Dai Vo, Takumitsu Kida, Toyoichiro Mori, Makoto Kitani, Norifumi Aridome, Akira Miyamoto
Summary: The study found that an injection-molded product made from poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVAL) exhibited expansion in the flow direction after postprocessing annealing. This was due to the transcrystallization of PLA from the deformed PVAL droplets during annealing. The injection-molded products showed a high degree of molecular orientation after annealing, unlike the unannealed products.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Masayuki Yamaguchi, Wen Shu, Takeyoshi Kimura, Hoang-Giang Dai Vo, Takumitsu Kida, Toyoichiro Mori, Makoto Kitani, Norifumi Aridome, Akira Miyamoto
Summary: The study found that a product made of poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVAL) through injection molding exhibited an abnormal dimensional change, expanding in the flow direction after postprocessing annealing. Although the addition of PVAL did not accelerate the crystallization of PLA during cooling, the PLA showed transcrystallization from the dispersed PVAL droplets during postprocessing annealing, resulting in a high degree of molecular orientation in the injection-molded products after annealing. This anomalous behavior is important for controlling dimensional change after processing.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Engineering, Chemical
Weiyuan Lin, Yoshiki Hamamoto, Yuta Hikima, Masahiro Ohshima
Summary: This study proposed a method to improve the surface appearance of polypropylene (PP) foams from the perspective of material properties. The method focused on reducing bubble size, delaying polymer solidification, squeezing bubbles at the mold-polymer interface, and redissolving bubbles into the polymer. Experimental results showed that the proposed method effectively improved the surface appearance of the foams.
POLYMER ENGINEERING AND SCIENCE
(2023)
Article
Polymer Science
C. Loyer, P. Ferreira, J-B Marijon, V Michel, G. Regnier, J. Vera, V Duval, E. Richaud
Summary: This study investigates the embrittlement caused by injection molding of Polybutylene terephthalate (PBT). The effect of temperature and residence time on the mechanical properties of PBT was studied. Macromolecular analysis and crystallinity measurements were conducted to discuss the results. It was found that embrittlement occurs exclusively through a chain scission process, with oxygen playing a negligible role in degradation. A simple kinetic model based on hydrogen abstraction near ester groups was developed to describe the thermolysis-induced degradation. A processing window was determined using this model, which can assist practitioners in processing PBT parts.
POLYMER DEGRADATION AND STABILITY
(2022)
Article
Physics, Applied
Sanaz Koohfar, Yasemin Ozbek, Hayden Bland, Zhan Zhang, Divine P. Kumah
Summary: The structural and magnetic properties of LSCO/LSMO heterostructures grown on (001)-oriented MgO by molecular beam epitaxy were investigated. Strain relaxation was observed within the first 2-3 unit cells of the film due to large film-substrate lattice mismatch. The presence of LSCO spacer and capping layers induced ferromagnetism in ultra-thin LSMO layers, with magnetic easy axis oriented in the film plane. Magnetic anisotropy of the superlattice was found to be significantly higher than bulk LSMO, highlighting the crucial role of interfacial interactions in tuning magnetic anisotropy at oxide interfaces.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Virginia C. Ritter, Samantha M. Mcdonald, Andrey V. Dobrynin, Stephen L. Craig, Matthew L. Becker
Summary: Most elastomers undergo strain-induced crystallization (SIC) under tension, and the molecular response of mechanophore activation may have an interplay with the macroscopic response of SIC. Thiol-yne-derived stereoelastomers doped with a dipropiolate-derivatized spiropyran (SP) mechanophore exhibit mechanochromism correlated with SIC, which is strain-rate-dependent. These polymers can be recycled by melt-pressing into new films, increasing their potential range of applications.
ADVANCED MATERIALS
(2023)
Article
Polymer Science
Mengxue Du, Katalee Jariyavidyanont, Regine Boldt, Muhammad Tariq, Matthieu Fischer, Yvonne Spoerer, Ines Kuehnert, Rene Androsch
Summary: This study analyzed the formation of crystal nuclei in injection-molded poly (L-lactic acid) (PLLA) and found that the number of nuclei varied in different regions of the molded component due to varying shear rates. The simulation results showed that the higher shear rate near the surface caused a higher number of nuclei in the skin region compared to the core region. However, shear-induced nuclei formation was also observed in the core region. By comparing the cold-crystallization kinetics and morphology with non-injection molded PLLA, it was concluded that both the skin and core regions had shear-induced nuclei formation. The simulated shear-rate data exceeded the critical specific work of flow for shear-induced nuclei formation in all regions of the component. This study demonstrates the importance of understanding the crystallization kinetics of shear and quiescent melt in PLLA for predicting structure formation in industrial processing.
Article
Polymer Science
Chenxu Zhou, Siyuan Dong, Ping Zhu, Jiguang Liu, Dujin Wang, Xia Dong
Summary: By studying the crystallization behavior and crystal form transition of the transparent polyamide PAPACM12, its macroscopic properties can be affected. The crystal transition and strain-induced crystallization during stretching deformation contribute to higher breaking strength and elongation of PAPACM12.
Article
Polymer Science
Masatoshi Tosaka, Kohji Tashiro
Article
Chemistry, Multidisciplinary
Lai Nang Duy, Ryo Sekiya, Masatoshi Tosaka, Shigeru Yamago, Takuya Matsumoto, Takashi Nishino, Takayuki Ichikawa, Takeharu Haino
Article
Materials Science, Multidisciplinary
Alice Gros, Bertrand Huneau, Erwan Verron, Masatoshi Tosaka
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2019)
Article
Polymer Science
Masatoshi Tosaka, Daiki Kumagawa
Article
Polymer Science
Podchara Rattanakawin, Kenji Yoshimoto, Yuta Hikima, Alvin Chandra, Teruaki Hayakawa, Masatoshi Tosaka, Shigeru Yamago, Masahiro Ohshima
Article
Polymer Science
Beomsu Park, Masatoshi Tosaka, Shigeru Yamago
Summary: Isotactic poly(N, N-diethyl acrylamide) (i-PDEAA) was synthesized by ytterbium triflate/H2O-catalyzed radical polymerization and its single crystals were successfully grown from solution. The lattice constants of Form-1 crystal were determined, while those of Form-2 crystal were only roughly estimated. The study provided insights into the crystallization of i-PDEAA and its crystal polymorphisms.
Article
Polymer Science
Yuhan Jiang, Weijia Fan, Masatoshi Tosaka, Michael F. Cunningham, Shigeru Yamago
Summary: High molecular weight poly(butyl acrylate)s and diblock copolymers were successfully synthesized using water-soluble organotellurium chain transfer agents in water, achieving high monomer conversion rates and low viscosity due to stable latex formation. The presence of termination reactions in reversible deactivation radical polymerization has been a limiting factor for synthesizing HMW polymers, but high end group fidelity was confirmed through block copolymer synthesis under the current conditions.
Article
Polymer Science
Podchara Rattanakawin, Kenji Yoshimoto, Yuta Hikima, Shinsuke Nagamine, Yuhan Jiang, Masatoshi Tosaka, Shigeru Yamago, Masahiro Ohshima
Summary: A method of fabricating highly ordered nanocellular foam using UV-induced chemical foaming technique and self-assembly of block copolymer PMMA-b-PtBA was reported. Different self-assembled morphologies were investigated for their effects on the formation of nanocellular foams. It was found that cells generated from the lamella templates had higher expandability compared to those from the cylindrical templates. Increasing the molecular weight of PMMA could mitigate the drastic change in cell structure.
Article
Polymer Science
Yuhan Jiang, Weijia Fan, Masatoshi Tosaka, Shigeru Yamago
Summary: In this study, structurally controlled high-molecular-weight (HMW) PSts and block copolymers were successfully synthesized using emulsion organotellurium-mediated radical polymerization (TERP). The method demonstrated high monomer conversion, high end-group fidelity, and rapid monomer diffusion, providing a valuable route for fabricating polymer materials based on HMW PSts.
Article
Chemistry, Multidisciplinary
Masatoshi Tosaka, Hinako Takeuchi, Masato Kibune, Tianxiang Tong, Nanyi Zhu, Shigeru Yamago
Summary: Stochastic simulation of the formation process of hyperbranched polymers (HBPs) using a branch-inducing monomer, evolmer, revealed that the observed dispersities (Ds) were due to the distribution of the number of branches instead of undesired side reactions. The simulation also showed that the branch structures were well controlled and the majority of HBPs had structures close to the ideal one. Furthermore, the simulation suggested a slight dependence of branch density on molecular weight, which was experimentally confirmed.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Materials Science, Textiles
Masatoshi Tosaka
Proceedings Paper
Polymer Science
Wenjuan Li, Masatoshi Tosaka, Shigeru Yamago
REVERSIBLE DEACTIVATION RADICAL POLYMERIZATION, VOL 1: MATERIALS AND APPLICATIONS
(2018)
Article
Chemistry, Multidisciplinary
Noboru Osaka, Yuichi Minematsu, Masatoshi Tosaka
Article
Materials Science, Textiles
Masatoshi Tosaka
Article
Chemistry, Multidisciplinary
Weijia Fan, Masatoshi Tosaka, Shigeru Yamago, Michael F. Cunningham
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2018)
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.
