Scientific Research Report
Study on properties and mechanism of polyimide fiber reinforced epoxy resin structure wave-transmitting composites
Li Yafeng, Zhang Dujuan, Qiu Yang, Lu Haijun
(1.Composite Technology Center, AVIC Manufacturing Technology Institute, Beijing 101300, China; 2.National Key Laboratory of Science and Technology on Advanced Composites, AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China)
【Abstract】Polyimide fiber and epoxy resin were selected, and the polyimide fiber/epoxy structure wave-transmitting composite material was prepared by hot melt method. By the means of Fourier transform infrared spectroscopy, moisture absorption, mechanical properties, dielectric properties, hygrothermal aging properties and scanning electron microscopy, the structural wave-transmitting properties and hygrothermal environment resistance of polyimide/epoxy structure wave-transmitting composites were studied. The research results showed that the rigid conjugate structure in the polyimide fiber gave the polyamide fiber composite with good wave-transmitting properties and hygrothermal resistance. However, compared with the quartz fiber reinforced epoxy resin composite, the polyimide fiber reinforced epoxy resin structure wave-transmitting composite still had the problems of low compression strength, flexural strength and interlaminar shear strength, and high moisture absorption rate. The results of failure mode analysis of mechanical properties showed that polyimide fiber also had the problems of moisture absorption of organic fiber, low compressive strength and poor fiber/resin interface bonding.
【Keywords】polyimide fiber; epoxy resin; wave-transmitting composites; mechanical property; dielectric property; hygrothermal resistance
Mechanism discussion and influencing factor analysis on interface weakening of electronic adhesive
Jin Zhili, Wang Lin, Xu Huanxiang, Wang Zihan, Tang Yanhuang
（The Fifth Electronics Research Institute of Ministry of Industry and Information Technology, Guangzhou 511370, Guangdong, China）
【Abstract】The bonding theory and microscopic forces at the interface were discussed, and the key factors affecting the interfacial bonding strength of electronic adhesive were discussed as well. The research in this paper showed that the microscopic forces described by adsorption theory, interlocking theory and diffusion theory had important contributions to the bonding of electronic adhesive, while the microscopic forces described by electrostatic theory and suction theory could be ignored. The interfacial chemical composition, wetting degree, interfacial contamination, interfacial morphology, temperature and mesophase thickness could significantly affect the interfacial bonding force. Finally, based on the above key factors and combined with relevant engineering experience, the interface weakening mechanism of electronic adhesive was reviewed.
【Keywords】electronic adhesive; bonding; interface weakening; mechanism discussion
Preparation of low modulus silane-modified polyether resin and study on sealant properties
Ren Jie1,2, Qu Rui3
[1. Skshu New Materials (Shanghai) Co., Ltd., Shanghai 201100, China; 2. Skshu Paint Co., Ltd., Putian 351100, Fujian China; 3. Shanghai Plastics Research Institute Co., Ltd., Shanghai 201702, China]
【Abstract】Silane-modified polyether polymer was synthesized from polypropylene glycol (PPG), N,N’-carbonyldiimidazole (CDI) and N-phenyl-3-aminopropyltrimethoxysilane as raw materials. The effects of reaction temperature, feed ratio and other conditions on polyether chain extension reaction were studied, and the optimum reaction conditions were selected. The research results showed that at the reaction temperature of 90 ℃, when n(CDI)∶n(PPG)=1.4∶1, the chain extension reaction effect of polyether and CDI was good, and the prepared silane-modified polyether resin had excellent performance. MS sealant prepared by the self-made resin had a wide range of substrate bonding property, excellent mechanical property, low tensile modulus and excellent elongation at break, which showed great application prospects in low modulus prefabricated building, home decoration and waterproof industries.
【Keywords】silane-modified polyether resin; MS sealant; N,N’-carbonyldiimidazole; low modulus
Research and analysis of compatibility between high-adhesion modified polysulfide sealant and anticorrosion coating
Dai Xiaoying, Wang Bo, Yang Xiaomin
(AVIC Xi’an Aircraft Industry Group Co., Ltd., Xi’an 710089, Shaanxi, China)
【Abstract】The physical and chemical properties, process properties and mechanical properties of high-adhesion modified polysulfide sealant (HM116C8) were studied. At the same time, the compatibility of HM116C8 sealant and anticorrosion coating (BFJ-1650) was studied with reference to the experimental design in the compatibility of aircraft integral fuel tank materials. The research results showed that HM116C8 sealant had good physical properties, process properties, low temperature resistance, corrosion resistance, liquid resistance and repairability, and had good adhesion performance with various materials. The integral fuel tank sealing system composed of anodized aluminum alloy+BFJ-1650 anticorrosion coating+NJD-3 primer+HM116C8 sealant had good compatibility among various materials, which could meet the requirements of adhesion between layers of the sealing system.
【Keywords】sealant; anticorrosion coating; bonding property; compatibility
Development and Application
Study on chemical load compatibility of silicone RTV sealant for vehicle LiDAR
Liu Zexuan, Wang Bing, Xu Shan, Lin Zhiqiang
(Guangzhou Huitian New Materials Co., Ltd., Guangzhou 510800, Guangdong, China)
【Abstract】The vehicle environment where the LiDAR is located will be exposed to a large amount of grease solvents. Therefore, the compatibility test of silicone RTV sealant and common solvents in this environment was carried out to study the tolerance of various properties of different formulation systems after immersing and aging. The research results showed that since the crosslinking density was generally lower than that of polyurethane and epoxy, the silicone RTV sealant should be specially formulated to reduce the swelling effect of grease on the system. At the same time, according to the provisions of ISO 16750-5—2018 standard, different degrees of immersion in different solvents and different temperatures were carried out to evaluate the aging condition. The filler system of oil-resistant silicone RTV sealant should try to choose a system with low oil absorption value such as CaCO3 or modify to lipophobic system to slow down the infiltration of oil molecules, and fumed silica filler should be cautiously used. Under the condition of not considering the risk of butanone oxime odor released after vulcanization, corrosion to metallic copper, or swelling polycarbonate (PC), the formula design of de-ketoxime formulation with high crosslinking density should be preferentially selected.
【Keywords】LiDAR; silicone RTV sealant; filler; crosslinking density; oil resistance
Preparation and properties of modified nano-TiO2/waterborne acrylate anti-aging coating
Liu Chuanqi1, Shen Jianqiang1, Gao Huiliang1, Zhang Xin2, Pei Kemei2
(1. Zhejiang Tiannv Group Paint Co., Ltd., Jiaxing 314505, Zhejiang, China; 2. Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, Zhejiang, China）
【Abstract】The self-made modified nano-TiO2 particle with strong ultraviolet absorption was used to blend with and modify the waterborne hydroxyacrylic secondary dispersion, and high-temperature baking coating was then prepared with amino resin. The effects of modified nano-TiO2 particle on the coating properties, especially the aging resistance behavior were studied. The research results showed that the nano-TiO2 particle modified by silica film could effectively improve the ultraviolet absorption performance of the material. When the proportion of modified nano-TiO2 particle in the coating was 0.4%, the coating had excellent mechanical properties such as hardness, adhesion and flexibility. Modified nano-TiO2 particle could significantly improve the aging resistance of the coating.
【Keywords】nano-TiO2; modification; hydroxyacrylic secondary dispersion; aging resistance
Study on preparation of all-water foamed polyurethane insulation material and its application in concrete dam protection
Yang Chen1, Luo Jianhua1, Ren Yinxia2, Sun Yongqi2
(1. Xinjiang Irtysh River Investment and Development (Group) Co., Ltd., Urumqi 830000, Xinjiang, China; 2.Xinjiang Keneng New Material Technology Co., Ltd., Urumqi 830022, Xinjiang, China)
【Abstract】The protective structure of “permanent anti-seepage coating, all-water foamed polyurethane rigid foam insulation material (seam seperation), reinforced anti-cracking mortar leveling layer and one-component polyurea waterproof coating” was used to protect the concrete panel in an upstream alpine region of Xinjiang for heat preservation, moisture retention and anti-freezing protection. The research results showed that by controlling the composite polyether, composite catalyst, water consumption and construction temperature, on-site spraying of all-water foamed polyurethane insulation material could be achieved, and the material had good dimensional stability and high compressive strength. By adopting the construction technology of “layer by layer gradually flexible release” and “block by block protection and internal stress release”, the cracking and falling off of the thermal insulation layer could be effectively prevented, and the protection effect of the concrete dam could be ensured.
【Keywords】all-water foaming; rigid polyurethane foam; alpine region; hydraulic concrete; heat preservation and moisture retention; spraying; environmental protection
Performance testing of domestic waterborne adhesive and polyurethane adhesive for floor cloth bonding
Sun Yuying1, Zhang Jiaxin2, Geng Shujiang2
(1.CRRC Tangshan Co., Ltd., Tangshan 064000, Hebei, China; 2.School of Metallurgy, Northeastern University, Shenyang 110819, Liaoning, China)
【Abstract】The domestic two kinds of waterborne adhesive (type I and type II) and one kind of two-component polyurethane adhesive were used as adhesive to bond the floor cloth to the floor of different materials, i.e. aluminum alloy and wood floor. The adhesive peel strength was tested, and the mode of bonding failure on different floor substrates was compared and analyzed. The research results showed that the peel strength of adhesive type I on aluminum alloy and wood floor was 1.182 and 1.731N/mm respectively, which not only had a certain bonding strength, but also could meet the requirements of removing the floor cloth of EMU, and was applicable to the bonding of the floor cloth at conduit ferrule of EMU. However, the peel strength of waterborne adhesive type II on aluminum alloy and wood floor substrate was 0.355 and 1.172 N/mm respectively, and it was not suitable to be used as adhesive for EMU floor cloth. The peel strength of domestic two-component polyurethane adhesive on aluminum alloy and wood floor substrate was 3.089 and 2.698 N/mm respectively, which had high bonding strength and was suitable to be used as adhesive for floor cloth of urban rail vehicles.
【Keywords】waterborne adhesive; two-component polyurethane adhesive; floor cloth; bonding performance
Special Topics and Review
Pickering emulsion polymerization and its application in adhesive related fields
Sun Guanqing, Xu Jianan, Liu Ren
（Key Laboratory of Synthetic and Biological Colloids Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, Jiangsu, China）
【Abstract】Pickering emulsion polymerization does not need or only needs a small amount of surfactant, and can prepare high-performance waterborne polymer dispersion system, which can solve the problems caused by surfactant migration, water absorption and other factors on the application of waterborne latex system in adhesive and coating, and has important value for developing high-performance waterborne adhesive. In this paper, the theoretical basis, polymerization mechanism of Pickering emulsion polymerization and its application in adhesive and coating fields were systematically introduced.
【Keywords】emulsion polymerization; Pickering emulsion polymerization; nanoparticle; adhesive; coating
Research progress on synthesis and application of core-shell polymer/metal composite microsphere
Feng Xiaotong, Deng Caishuang, Liao Jiancong, Jiang Yiming, Hu Yang
[Lescent (China) Advanced Materials Co., Ltd., The Research Center of Fine Polymer (Lescent) Engineering and Technology of Guangdong Province, Jiangmen 529157, Guangdong, China]
【Abstract】The preparation of core-shell composite microsphere could realize the design and optimization of particle properties, especially the semi-organic and semi-inorganic spherical materials with polymer microsphere as the core and metal layers as the shell, which had become a research hotspot in the field of conductive microsphere in recent years. In this paper, the main preparation methods of core-shell polymer/metal composite microsphere, such as magnetron sputtering method, sol-gel method, in-situ reduction method, layer-by-layer self-assembly method and UV irradiation method were reviewed, and their advantages and disadvantages were summarized as well. The application of such microsphere in specific fields such as anisotropic conductive film (ACF), sewage treatment, wave absorbing material and surface-enhanced Raman scattering (SERS) were introduced, and their future development was also prospected.
【Keywords】polymer/metal composite microsphere; core-shell structure; synthesis; application; prospect
Research and application progress of silicone pressure sensitive adhesive
Yuan Xu, Zhou Changwei, Wang Yan, Liu Tian
(Guangzhou Ruihe New Material Technology Co., Ltd., Guangzhou 510800, Guangdong, China)
【Abstract】Starting from the curing mechanism, raw material composition, structure and properties of silicone pressure sensitive adhesive, the functional exploration of silicone pressure sensitive adhesives in high temperature/high humidity resistance, antistatic/conductive properties as well as the research/improvement ideas and improvement results in application process optimization such as high solid content, emulsion, no primer, photo-initiated system, and the stability of AF anti-fingerprint screen products were analyzed and summarized. Finally, the application prospect and future focus direction of silicone pressure sensitive adhesive were prospected.
【Keywords】silicone pressure sensitive adhesive; silicone rubber; MQ silicone resin; overview
Brief discussion on testing standard for mold resistance of building material at home and abroad
Hu Xiaozhen1,2,Gu Chenrong1,Xu Yanhua1,2
（1.Shanghai Jianke Technical Assessment of Construction Co., Ltd., Shanghai 200032, China；2.National Center for Quality Supervision and Test of Building Engineering Materials, Shanghai 201108, China）
【Abstract】Mold resistance has become a major direction for the future development of various building materials, and the testing standards for mold resistance of various building materials are constantly being introduced and improved. In this study, the commonly used mold resistance testing standards for building materials at home and abroad were summarized, and the sample preparation methods, test culture media and test bacteria were compared and analyzed. Through the analysis of the domestic and foreign mold resistance testing standards, it was found that there were complete domestic testing standards for coating products, wood and bamboo products and rubber products, but there were no domestic testing standards for adhesive, plastic floor, and waterproofing membrane. Therefore, the testing standards for these products could be developed by referring to the corresponding domestic and foreign standards.
【Keywords】building material; mold resistance; testing standard