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Highly Soluble Phenylethynyl-terminated Imide Oligomers and thermosetting Polyimides Based on 2,2′3,3′-Biphenyltetracarboxylic Dianhydride

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Chemical Research in Chinese Universities 2019年第3期35卷 530-536页

作者： MENG Xiangsheng LU Gewu LIU Xiuju MENG Qingjie SHI Junwei YUAN Hang KE Hongjun WANG Xianwei FAN Weifeng LIU Jingfeng YAN Jingling WANG Zhen Laboratory of Polymer Composites Engineering Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022P.R.China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201P.R.China Aerospace Research Institute of Special Materials and Technology Beijing 100076P.R.China Shandong Non-metallic Materials Institute Jinan 250031P.R.China

The properties of a series of imide oligomers were characterized according to their molecular weights, solubility, and thermal and rheological properties. This series of imide oligomers was synthesized via a two-step method using 2,2′,3,3′-biphenyltetracarboxylic dianhydride(3,3′-BPDA) and aromatic diamines as the monomers, and 4-phenylethynyl phtlialic anhydride(PEPA) as the end-capping agent. The imide oligomers based on 3,3′-BPDA showed excellent solubility in low boiling point solvents and low melt viscosity, which were attributed to their unique bent architectures. High-performance thermosetting polyimides were produced from these oligomers via thermal crosslinking of the phenylethynyl groups. The mechanical and thermal properties of the thermosets were studied using tensile testing, dynamic mechanical thermal analysis(DMTA), and thermogravimetric analysis(TGA). The 3,3′EPDA-based thermosets exhibited excellent thermal properties, with glass transition temperatures of up to 455℃, and 5% mass loss temperatures of up to 569℃ in air. The thermosets based on 3,3-BPDA showed superior thermal properties compared to those derived from TriA-X series oligomers.

关键词： 2,2′,3,3′-Biphenyltetracarboxylic dianhydride Phenylethynyl-terminated imide oligomer Solubility Processability thermosetting polyimide

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Phase separation time/temperature dependence of thermoplastics-modified thermosetting systems

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Frontiers of Chemical Science and Engineering 2008年第3期2卷 276-285页

作者： Xiujuan ZHANG Xiaosu YI Yuanze XU The Key Laboratory of Molecular Engineering of Polymers Ministry of EducationDepartment of Macromolecular ScienceFudan UniversityShanghai 200433China Institute Aeronautic Materials Beijing 100095China

The cure-induced phase separation processes of various thermoplastics(TP)-modified thermosetting systems which show upper critical solution temperature(UCST)or lower critical solution temperature(LCST)were studied with emphasis on the temperature dependency of the phase separation time and its potential application in the cure time-temperature processing *** found that the phase separation time/temperature relationship follows the simple Arrhenius *** cure-induced phase separation activation energy E_(a)(ps)generated from the linear fitting of the Arrhenius equation is irrelevant to the detection means of phase separation *** also found that E_(a)(ps)is insensitive to TP content,TP molecular weight and curing rate,but it changes with the cure reaction kinetics and the chemical environment of the *** the established phase separation time-temperature dependence relation,we can easily establish the whole cure time-temperature transformation(TTT)diagram with morphology information which is a useful map for the TP/TS composites processing industry.

关键词： polymerization induced phase separation thermosetting thermoplastic time and temperature dependence Arrhenius equation TTT diagram

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Spreading and Curing Behaviors of a thermosetting Droplet-Silicone on a Heated Surface

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Journal of Harbin Institute of Technology(New Series) 2019年第4期26卷 1-8页

作者： Xingjian Yu Run Hu Liliang Zhou Han Wu Xiaobing Luo School of Energy and Power Engineering Huazhong University of Science and Technology

thermosetting materials are widely used as encapsulation in the electrical packaging to protect the core electronic components from external force, moisture, dust, and other factors. However, the spreading and curing behaviors of such kind of fluid on a heated surface have been rarely explored. In this study, we experimentally and numerically investigated the spreading and curing behaviors of the silicone(OE6550 A/B, which is widely used in the light-emitting diode packaging) droplet with diameter of ~2.2 mm on a heated surface with temperature ranging from 25 ℃ to 250 ℃. For the experiments, we established a setup with high-speed camera and heating unit to capture the fast spreading process of the silicone droplet on the heated surface. For the numerical simulation, we built a viscosity model of the silicone by using the Kiuna’s model and combined the viscosity model with the Volume of Fluid(VOF) model by the User Defined Function(UDF) method. The results show that the surface temperature significantly affected the spreading behaviors of the silicone droplet since it determines the temperature and viscosity distribution inside the droplet. For surface temperature varied from 25 ℃ to 250 ℃, the final contact radius changed from ~2.95 mm to ~1.78 mm and the total spreading time changed from ~511 s to ~0.15 s. By further analyzing the viscosity evolution of the droplet, we found that the decreasing of the total spreading time was caused by the decrease of the viscosity under high surface temperature at initial spreading stage, while the reduction of the final contact radius was caused by the curing of the precursor film. This study supplies a strategy to tuning the spreading and curing behavior of silicone by imposing high surface temperature, which is of great importance to the electronic packaging.

关键词： thermosetting material silicone surface temperature spreading and curing

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Challenging multiphase complex fluids for applications

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Journal of Central South University 2008年第S1期15卷 130-134页

作者：许元泽 Department of Macromolecular Science Fudan University Key Laboratory of Molecular Engineering of Polymers of Ministry of Education Fudan University

Modern processing technology is calling the scientific understanding of dynamic processes,where the science of complex fluids plays a central *** summarize our recent efforts using the generic approaches of multi-scale physics of complex fluids on apparently irrelevant processes,*** mixing of polymer blends,the processing of thermoplastic(TP) toughened thermosetting(TS) composites using phase separation of TP in TS,as well as the enhanced oil recovery using polymer soft *** is emphasized that the thorough physical understanding in multi-scales of time and space through the joint efforts of experiment and theory in each scale is the key issue for the modeling of various processes.

关键词： complex fluid multi-scale physics polymer blend phase separation thermosetting composite soft gel EOR

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The Effect of Epoxy Concentration and Fibre Loading on the Mechanical Properties of ABS/Epoxy-Coated Kenaf Fibre Composites

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Open Journal of Composite Materials 2015年第2期5卷 41-48页

作者： Hafsat R. Saliu U. S. Ishiaku M. K. Yakubu E. G. Kolawole S. S. Adefila M. B. Abu Bakar Z. A. Moh’d Ishak Department of Textile Science and Technology Ahmadu Bello University Zaria Nigeria Department of Chemical Engineering Ahmadu Bello University Zaria Nigeria School of Materials and Mineral Resources Engineering Engineering Campus Universiti Sains Malaysia Penang Malaysia

In this work, thermosetting resin, epoxy and fibre loading were used in optimizing the strength at which ABS/epoxy coated kenaf fibre (EKF) composites would perform apparently during mechanical stress. Kenaf bast fibres were resin coated before incorporated into engineering thermoplastic ABS at its processing temperature (230°C), cured in-situ at internal mixer and later compression moulded at 210°C under 65 kg/cm2pressure. The results showed the optimum level of tensile strength with thermoset and fibre loading as well as increase in strong interfacial bonding while the hardness values increased with increasing thermosetting and fibre contents. Both the tensile and flexural modulus apparently increased as the fibre contents increased.

关键词： thermosetting Resin Kenaf Fibre Engineering Thermoplastic ABS

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Mechanical Properties of Carbon Epoxy Prepreg Insert Phenolic Resin Injection Moldings

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纤维复合材料 2019年第2期36卷 3-7页

作者： PINPATHOMRAT Badin KEIGO Nishitani THUMSORN Supaphom Narongchai O-Charoen Yuqiu YANG HAMADA Hiroyuki Department o f Advanced Fibro-Science Kyoto Institute of Technology Matsugasaki Sakyo-ku Kyoto 606-8585 Japan Department of Industrial Engineering Pathumwan Institute of Technology Department of Materials and Metallurgical Engineering Rajamangala University of Technology Thanyaburi Klong 6 Thanyaburi Pathumthani 12110 Thailand Key Laboratory of Textile Science & Technology Ministry of Education College of Textiles Donghua University Shanghai 201620 PR China

This study focuses on the insert-injection molding process. The thermoset composite inserts in this study were carbon fiber/epoxy (CF/Epoxy) prepreg sheets. The injected molded part was glass fiber contained phenolic resin (GF/PF). The CF/Epoxy was placed in the mold cavity prior to injecting GF/PF onto the inserted injection molded CF/Epoxy specimens. The role of adhesion between the inserted part and injected resin on the mechanical properties was evaluated by 3 point bending and impact tests. In addition, the effect of prepreg orientation on the mechanical properties of the prepreg inserted-injection molding system was investigated. It was found that the prepreg with unidirectional orientation significantly improved flexural and impact strength of the inserted injection molding composites, providing better support and resistance to bending and impact loading. The main failure modes of the specimens were structural and adhesive failure.

关键词： insert injection molding unidirectional prepregs woven fabric prepreg thermosetting composite

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