Article
Materials Science, Multidisciplinary
Sai Wang, Haoyang Feng, Jianming Hong, Guilong Wang
Summary: This study investigates the improvement in the foaming of thermoplastic polyurethane (TPU) by enhancing the crystallization of hard segments. The effects of packing time in MOFIM technology on the crystallization behavior of hard segments and the cell morphology of TPU foams are studied. It is found that prolonging the packing time increases the crystallinity of TPU solids and foams due to closer-packed crystals. The enhanced foamability of TPU is attributed to both increased crystallinity of hard segments and broader distribution of crystals at the same crystallinity. Moreover, TPU foams with higher hardness have smaller cell size, higher cell density, and narrower distribution in cell size due to their higher viscosity and storage modulus.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Polymer Science
Long Wang, Minghui Wu, Qian Ren, Zhengsheng Weng, Wanwan Li, Xiuyu Zhu, Wenge Zheng, Xiaosu Yi
Summary: Polypropylene/carbon nanostructure (PP/CNS) nanocomposite foams with high void fraction and good mechanical properties were successfully prepared using foam injection molding technique. The addition of carbon nanostructures improved the melt strength and crystallization process of PP, and a high mold temperature overcame the adverse effect of CNS, leading to significantly increased cell density.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Engineering, Chemical
Zhengsheng Weng, Qian Ren, Minghui Wu, Xiuyu Zhu, Wanwan Li, Long Wang, Wenge Zheng
Summary: PVDF foam materials with excellent mechanical properties were successfully fabricated by adding PMMA as a modifier, using supercritical CO2 as a blowing agent, and employing foam injection molding technology.
POLYMER ENGINEERING AND SCIENCE
(2022)
Article
Polymer Science
Chen-Yuan Chung, Shyh-Shin Hwang, Shia-Chung Chen, Ming-Chien Lai
Summary: The study utilized PP and PS as matrix materials with exothermic foaming agents, conducting injection molding to investigate the effects of different process parameters on foam characteristics. Through experimental design and microscopic observation, the optimal expansion ratios were determined for the two matrix materials.
Article
Polymer Science
Kentaro Taki, Marco Menale, Giovanni Pisante, Ernesto Di Maio
Summary: A visual observation experiment was conducted to mimic the pressure history in foam injection molding and infer the bubble formation in core-back operations. The experiment examined the stages of bubble nucleation, dissolution, and re-nucleation corresponding to injection, packing, and core-back opening, respectively. The study revealed a reduction in the density of re-nucleated bubbles compared to the initial nucleation. By analyzing the evolution of the blowing agent concentration around dissolved bubbles, a characteristic time was introduced to achieve uniformity and cancel the memory of the system. A numerical model based on Fickian behavior was derived and validated, providing a predictive tool for designing core-back operations in foam injection molding.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Pengke Huang, Yaozhuo Su, Haibin Luo, Xiaoqin Lan, Yunkai Chong, Fei Wu, Wenge Zheng
Summary: A novel method for continuous production of expanded polypropylene (EPP) foam beads via supercritical CO2 (scCO2) extrusion foaming coupled with a wind cutting device is developed, and the real-time cell growth and pelletizing processes of the extruded bead foams are revealed for the first time. This method can greatly shorten production time, save energy consumption, and promote structural diversification. In addition, the transformation of foamed beads and the mechanical and thermal insulation properties of the prepared foamed products are also investigated.
JOURNAL OF CO2 UTILIZATION
(2022)
Article
Multidisciplinary Sciences
Songyan Li, Shaopeng Li, Kexin Du, Jianzhong Zhu, Liying Shang, Kaiqiang Zhang
Summary: In this study, a CO2-switchable foam was synthesized by adding hydrophilic nanoparticles to the foaming agent, resulting in improved stability and longer half-life. This research is significant for future CO2 foam research and applications in energy and environmental practices.
Article
Polymer Science
Po-Wei Huang, Hsin-Shu Peng, Sheng-Jye Hwang, Chao-Tsai Huang
Summary: This investigation developed a structural foam injection molding technology using gas supply equipment connected to the unique plasticizing mechanism of the injection machine. The study examined its impact on the melt rheology quality and foam structures of specimens. The experiment used polypropylene (PP) as the forming material and nitrogen (N-2) as the gas for mixing and forming foaming characteristics. Through the connection of the nitrogen supply equipment to the unique plasticizing mechanism, gas and molten plastic can be mixed during the screw plasticizing stage, achieving a foaming effect during the melt-filling process. The study found that an increase in N-2 fill content increased melt fluidity, and the foaming characteristic depended on the gas thermodynamic instability and pressure release.
Article
Polymer Science
Chung-Chih Lin, Chao-Long Yang
Summary: In this work, a novel method is proposed to manufacture complicated hollow products without limitations on resin type and with a lower energy consumption process. This method utilizes a water-soluble core and a shell to achieve the desired internal contour of the product, resulting in improved product quality.
Article
Chemistry, Multidisciplinary
Qian Ren, Minghui Wu, Zhengsheng Weng, Long Wang, Wenge Zheng, Yuta Hikima, Masahiro Ohshima
Summary: An innovative method combining sorbitol gelling agent and low-pressure microcellular injection molding (MIM) technique was reported to produce high-performance polypropylene (PP) foams. The addition of sorbitol gelling agent notably enhanced the crystallization, viscoelasticity and melt strength of PP, resulting in PP foams with well-defined cellular structures and increased tensile toughness and strength. The scalable and novel FIM technique shows promising future applications in automotive, construction and electrical components.
JOURNAL OF CO2 UTILIZATION
(2021)
Article
Polymer Science
Shia-Chung Chen, Che-Wei Chang, Chia-Yen Tseng, En-Nien Shen, Ching-Te Feng
Summary: This study demonstrates the successful control of foaming cell size and uniformity in size distribution in microcellular injection molding of polystyrene (PS). A preliminary study in the molding of elastomer thermoplastic polyurethanes (TPU) using the P-T path also shows promising results.
Article
Energy & Fuels
Linh Le, Raja Ramanathan, Tariq Almubarak, Hisham A. Nasr-El-Din
Summary: Switchable ethoxylated amine surfactants are highly soluble in CO2 and high-saline brines, making them suitable for maximizing the foamability and stability of CO2 foam at elevated temperatures. The study found that using Ethomeen C12 (EC12) as a surfactant can enhance foam stability under high-saline conditions, with optimal parameters being 1.5 wt% EC12 concentration, 25 wt% NaCl salinity, and pH 6.5. The presence of salt significantly improved foam stability, while absence of salt led to poor foam stability, indicating the importance of salt influence on foam behavior.
Article
Engineering, Chemical
Constantin Ott, Dietmar Drummer
Summary: Foam injection molding process was used to encapsulate FR4 with Polyamid66 in order to achieve high-quality assembly production and protect against external influences. Successful tests showed low leakage rate and shear stress, demonstrating the suitability of the new solution concept.
POLYMER ENGINEERING AND SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Yaozhuo Su, Pengke Huang, Haibin Luo, Yunkai Chong, Yongqing Zhao, Minghui Wu, Hao Zheng, Xiaoqin Lan, Fei Wu, Wenge Zheng
Summary: This study creatively used supercritical CO2 extrusion foaming combined with wind-cooling granulator technology to prepare controllable polypropylene (PP)/thermoplastic polyurethane (TPU) composite bead foams. The process of polymer melting, gas dispersion, foaming, and pelletizing can be completed in one continuous step, with advantages such as high efficiency, low cost, and controllable cellular structures. The effect of processing parameters on the cellular structures and properties of the foam board was also studied. The prepared foam board exhibited low density and thermal conductivity, making it suitable for thermal insulation applications.
ACS APPLIED POLYMER MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Jung H. Lee, Raymond K. M. Chu, Ruosong Li, Kermit Kwan, Chul B. Park
Summary: This study utilized the one-step batch foaming technique with supercritical carbon dioxide as a physical blowing agent to develop microcellular foams from polysulfone and polyethersulfone. The results showed that different pressure and temperature conditions led to variations in cell densities and expansion ratios of the foams produced.
JOURNAL OF CO2 UTILIZATION
(2022)
Article
Polymer Science
Shinsuke Nagamine, Yosuke Mizuno, Yuta Hikima, Kiyomi Okada, Long Wang, Masahiro Ohshima
Summary: Cellulose microfibers modified with polydopamine and octadecylamine showed improved dispersibility and reinforcing effects in polypropylene matrix. Proper alkylation can enhance the tensile modulus of the composite, while excess alkylation may decrease the performance. Composites fabricated by injection molding exhibited better tensile properties compared to those prepared by batch mixing.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Materials Science, Characterization & Testing
Shun Muroga, Yu Takahashi, Yuta Hikima, Seisuke Ata, Masahiro Ohshima, Toshiya Okazaki, Kenji Hata
Summary: A nondestructive method using ATR-FTIR spectroscopy was proposed to evaluate the curing degree of cured rubbers and their nanocomposites, specifically in fluorine-based rubber. The study found that the FWHM of the C=O band can be used as a standard to measure the crosslinking density, showing good applicability in the presence of various nanofillers. Additionally, the study revealed that FWHM was more sensitive to changes in crosslinking density when fillers like CNTs were added to the rubber compared to changes in Young's modulus.
Article
Chemistry, Applied
Qian Ren, Minghui Wu, Zhengsheng Weng, Xiuyu Zhu, Wanwan Li, Pengke Huang, Long Wang, Wenge Zheng, Masahiro Ohshima
Summary: The addition of cellulose nanofibers (CNFs) significantly reduced the half-crystallization time of the PLLA/PDLA blend, and when 3% modified CNFs were incorporated, almost exclusively SC crystallites were formed with no HC crystallite presence. This was speculated to be due to enhanced interchain molecular interactions between CNFs and PLA, presenting a feasible and efficient method for producing high-performance PLA materials with exclusively SC crystallites.
CARBOHYDRATE POLYMERS
(2022)
Article
Chemistry, Multidisciplinary
Koji Nishida, Yuta Hikima, Tsuyoshi Koga, Masahiro Ohshima
Summary: By combining the nonequilibrium nature of a polymeric material and a rapid temperature-jump technique, a polymer crystallite with a ring-like morphology was obtained, and the phenomenon of melting point inversion was observed.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Engineering, Chemical
Mina Farahani, Yousef Jahani, Ali Kakanejadifard, Masahiro Ohshima
Summary: This study investigates the influence of a temperature-sensitive nucleating agent on the crystallization and rheological properties of polypropylene. The self-assembly behavior of the nucleating agent molecules is found to have a significant impact on the rheology of molten polypropylene. By controlling the nucleating agent content and process temperature, the formation of larger fibrils and increased viscosity and storage modulus can be achieved.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Polymer Science
Dongho Kim, Yuta Hikima, Masahiro Ohshima
Summary: In this study, microcellular foams with unique cellular structures were prepared from blends of poly(lactic acid) (PLA) and poly(butylene succinate-co-adipate) (PBSA). The blend morphologies and cellular structures were investigated for different blend ratios, with a 50/50 PLA/PBSA blend showing a layered structure. By utilizing the unique blend morphology and viscosity differences of the polymers, a millefeuille-like microcellular structure was created, resulting in foams with unique anisotropic mechanical properties.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
Article
Engineering, Chemical
Xiao Yuan Chen, Shinsuke Nagamine, Masahiro Ohshima, Denis Rodrigue
Summary: In this study, silica xerogels and PE-silica xerogel foams were successfully prepared using various precursors, surfactants, and solvents, showing excellent thermal insulation properties compared to conventional insulation materials. The presence of silica xerogel led to improved compressive modulus and density of the PE foam, making them promising candidates for cost-effective thermal insulation applications.
POLYMER ENGINEERING AND SCIENCE
(2022)
Article
Materials Science, Paper & Wood
Jisuk Lee, Yuta Hikima, Takafumi Sekiguchi, Masahiro Ohshima
Summary: The rheological and thermal properties of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and chemically modified cellulose nanofiber nanocomposites (PHBH/CNF) were studied. The composite material showed improved crystallization rate, viscosity, and mechanical properties compared to pure PHBH. The injection molding process was successfully used to enhance the processability of PHBH.
Article
Polymer Science
Weiyuan Lin, Yuta Hikima, Masahiro Ohshima
Summary: Styrene-isobutylene-styrene copolymer (SIBS) is a thermoplastic elastomer with excellent chemical stability, biocompatibility, and low gas permeability. By introducing polypropylene (PP) in foam injection molding processes, the foamability can be improved and the shrinkage of SIBS foams can be impeded.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
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
Kentaro Taki, Marco Menale, Giovanni Pisante, Ernesto Di Maio
Summary: A visual observation experiment was conducted to mimic the pressure history in foam injection molding and infer the bubble formation in core-back operations. The experiment examined the stages of bubble nucleation, dissolution, and re-nucleation corresponding to injection, packing, and core-back opening, respectively. The study revealed a reduction in the density of re-nucleated bubbles compared to the initial nucleation. By analyzing the evolution of the blowing agent concentration around dissolved bubbles, a characteristic time was introduced to achieve uniformity and cancel the memory of the system. A numerical model based on Fickian behavior was derived and validated, providing a predictive tool for designing core-back operations in foam injection molding.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
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
Tsukasa Kida, Masatoshi Ohara, Keigo Inamori, Shogo Nagasawa, Shin-ichi Kihara, Kentaro Taki
Summary: A sensing technology was developed to measure the plastication process of pellets in a co-rotating twin-screw extruder using acoustic emission simulation. This study provides an effective solution for product homogeneity and stability in the plastic industry.
Article
Engineering, Chemical
Yuto Mori, Soichiro Kishimoto, Rajesh Kumar Sharma, Kentaro Taki
Summary: This study demonstrated the successful separation of the metal/polymer interface in a multimaterial product using gas bubble nucleation. Two separation modes, cohesive failure and interfacial delamination, were observed depending on the heating temperature. The maximum load was reduced by 50% compared to the control, paving the way for recycling multimaterial products.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Polymer Science
Jisuk Lee, Kenta Moriyama, Yuta Hikima, Masahiro Ohshima
Summary: Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) foams were prepared using nitrogen as a physical blowing agent. The foam injection molding process and the melt memory effect were used to achieve microcellular foams with small cell size and high cell density. Mechanical properties evaluation showed that a high ductility PHBH foam was obtained at a melting temperature of 150 degrees C.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)