Scientific Research Report
Bulk synthesis and properties of UPy-terminated supramolecular peelable hot melt adhesive
Rao Houdong1, Zhang Ling1, Cheng Wei1, Wang Wenfei1, Yuan Yu2, Wei Liuhe2, Li Yuhan2
(1.CSSC Luoyang Ship Material Research Institute, Luoyang 471027, Henan, China; 2.College of Chemistry, Zhengzhou University, Zhengzhou 450001, Henan, China)
【Abstract】Reusable and recyclable adhesives are an inevitable trend in the development of the electronic industry. In this study, polyurethane prepolymer was synthesized by using polyester polyols (7130), polyethylene glycol (PEG-1500) and isophorone diisocyanate (IPDI) as raw materials through bulk polymerization. Then it was terminated with 2-amino-4-hydroxy-6-methylpyrimidine (UPy) and inserted into the UPy sequence at the end of the linear polyurethane to form self-complementary quadruple hydrogen bonds, the supramolecular polyurethane hot melt adhesive (HMA-UPy) with excellent mechanical properties, bonding properties, impact resistance, and reusability was synthesized, and its structure and various properties were measured or characterized. The research results showed that, ⑴ HMA-UPy was successfully synthesized, and the molecular weight of this hot melt adhesive was smaller than that obtained by conventional polyurethane hotmelt adhesive method. ⑵ Introducing UPy crosslinking agent into the polymer end had no significant effect on the glass transition temperature (Tg) of the soft chain segment. The UPy sequence provided high thermal mechanical stability and fast kinetic reversibility, and the UPy sequence at the polymer chain end did not damage the block structure of soft chain segment based on PEG-7130, making HMA-UPy soft, stretchable, but tough. ⑶ This hot melt adhesive was easy to process, reusable, with good mechanical strength, moderate viscous flow transition temperature (135 ℃), and fast dynamic reversibility of hydrogen bonds, making it very suitable for multiple peeling and repeated bonding. ⑷ This hot melt adhesive had two weight loss peaks, namely 338.03 and 428.34 ℃, which were much higher than the hot melting temperature of conventional hot melt adhesive and fully met the usage requirements. ⑸ This synthesis strategy was expected to open up a new path for designing impact resistance and reusable hot melt structural adhesive. It proposed a new strategy for developing high-strength, peelable, reusable, and impact resistance thermally reversible adhesive and provided an effective solution for their application in industrial production.
【Keywords】hot melt adhesive; impact resistance; repeatable; high-strength; self-complementary quadruple hydrogen bonds
Development of new sulfone-containing epoxy adhesive
Lai Lixing, Yu Xinhai
(College of Chemistry and Chemical Engineering, Donghua University 201620, Shanghai, China)
【Abstract】Epoxy adhesive systems consisting mainly of bisphenol S epoxy resin, E-51 epoxy resin and SRTEM-80 epoxy resin were investigated, and by changing the ratio of bisphenol S epoxy resin, E-51 epoxy resin and SRTEM-80 epoxy resin in the adhesive system, the epoxy adhesive systems containing sulfone such as SJ-1, SJ-2, SJ-3, SJ-4 and SJ-5 were prepared through a series of chemical reactions. The viscosity, gelation time, apparent activation energy, mechanical properties, electrical properties, water absorption properties were systematically studied, and the formulation and preparation process were optimized. The research results showed that bisphenol S epoxy resin and SRTEM-80 epoxy resin had more active groups, which could increase the activity of the crosslinking reaction of the adhesive system and accelerate the crosslinking speed, resulting in a shorter gelation time of the adhesive system. The mechanical properties, electrical properties, and hydrophobicity of the five adhesives were all good, and the various properties of SJ-3 adhesive were superior to other formulations. After curing, the tensile strength of SJ-3 adhesive was 32.3 MPa, the capacitance was 5.94-5.98 pF, the dielectric loss was 0.37%-0.51%, and the water absorption rate was only 0.16%, which was a reasonable formulation with great application prospects.
【Keywords】bisphenol S epoxy resin; epoxy adhesive; sulfone-containing epoxy adhesive; preparation; property
Preparation and properties of modified boron nitride/waterborne epoxy thermally conductive insulation coating
Huang Peng, Pei Kemei
(School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310020, Zhejiang, China)
【Abstract】A series of coupling agent modified BN samples (mBN-550, mBN-560 and mBN-570) were prepared by hydroxylation of boron nitride (BN) in sodium hydroxide solution and modification with three kinds of silane coupling agent (KH-550, KH-560 and KH-570). The optimal type and content of modified silane coupling agent were determined through dispersion performance testing. The waterborne epoxy thermally conductive insulation coating was prepared by adding mBN-570 with the best dispersibility to the waterborne epoxy coating. The effect of mBN-570 content on the mechanical properties, thermal conductivity, heat resistance, and insulation properties of the composite coating was studied. The research results showed that, ⑴ The dispersibility of modified BN in epoxy resin solution was improved, and the mBN-570 modified with 3% KH-570 had the best dispersion effect, with the dispersion time of 18 days. ⑵ The mechanical performance test indicated that when the content of mBN-570 was 3% and 5%, the mechanical properties of mBN-570/EP composite coating were relatively optimal. ⑶ The thermal conductivity test indicated that the thermal conductivity of the 5%mBN-570/EP composite coating at room temperature was 0.245 W/(mK), which was 28.3% higher than that of the pure EP coating. At the same time, the heat dissipation rate of the 5%mBN-570/EP composite coating was significantly faster than that of the pure EP coating. Therefore, the addition of 5%mBN-570 improved the thermal conductivity of the composite coating. ⑷ The thermal stability test indicated that the addition of 5%mBN-570 significantly enhanced the thermal stability of the composite material and delayed the thermal degradation process. ⑸ The insulation performance test indicated that the volume resistivity of the 5%mBN-570/EP composite coating was 2.65×1016 Ωcm, the surface resistivity was 4.73×1016 Ω, therefore this composite coating had good electrical insulation performance.
【Keywords】waterborne epoxy resin; boron nitride; surface modification; thermally conductive insulation coating
Preparation and performance characterization of novel UV adhesive for LED glass display substrate
Li Xiaoyuan, Luo Wenhui, Huang Fuming, Huang Lu, Li Yikun
(Tianjin Normal University, Tianjin 300387, China)
【Abstract】UV adhesive for light display substrate was prepared by using alicyclic epoxy resin as matrix resin and aluminum nitride (AlN) as thermal conductive filler. The material was overall evaluated by testing the comprehensive performance between the UV adhesive on the substrate and the copper foil, including thermal conductivity, peel strength, immersion welding resistance, reliability analysis and light transmittance test. The research results showed that, in the adhesive solution with m(TA3150):m(TA21)=40:60, the content of photoinitiator was 3.5% of epoxy resin mass fraction, the content of photopromoter was 6% of epoxy resin mass fraction, the content of AlN was 60% of epoxy resin mass fraction, the UV adhesive could be quickly cured. Its thermal conductivity was 1.1 W/(m∙K), peel strength was 1.20 N/mm, immersion welding resistance time reached 10 minutes, and light transmittance was 86%. It had good reliability and met the performance requirements of LED glass display substrate preparation, which had broad application prospects.
【Keywords】epoxy resin; UV adhesive; thermal conductivity; peel strength; light transmittance; reliability
Development and Application
Effect of continuous aging at high temperature on static characteristics of vehicle adhesive joints
Yang Yang1, Lin Yinghao2, Wang Yuanwu3, Fan Yisa2
(1. Materials and Transportation Research Institute, Peter the Great Saint-Petersburg Polytechnic University, Saint-Petersburg 195251, Russia; 2. School of Mechanical Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450040, Henan, China;3.CRRC Tangshan Co., Ltd., Tangshan 064000, Hebei, China）
【Abstract】The butt joint was selected to be aged for 144, 288, 432, 576, and 720 hours respectively, at high temperature of 80 ℃, and the failure load of the joint at room temperature for different aging time was tested. The failure load was divided into six levels: 100%, 60%, 50%, 40%, 30%, and 20% for fatigue testing, and the corresponding number of fatigue failure of load level joints was obtained. The joint fatigue life function based on the number of fatigue failure was established, and the effect of different aging time on the joint fatigue life was compared. Finally, the microstructure of the failure joint surface was compared and observed by using scanning electron microscopy. The research results showed that, ⑴ Under the condition of 80 ℃, as the aging time increased, the average failure strength of the butt joint slowly decreased. After 720 hours of high temperature aging, the average failure strength of the joint decreased by 16.55% compared to the initial value. ⑵ All load-displacement curves exhibited nonlinear changes. Under the condition of 80 ℃, as the aging time increased, the joint failure displacement gradually decreased, indicating that high temperature aging led to a decrease in the toughness of the adhesive. Although the failure displacement gradually decreased with aging time, the slope of the load-displacement curve gradually increased with aging time. ⑶ Under different aging time, the microstructure of the fatigue failure section of the joint underwent significant changes. ⑷ The fatigue test data showed that the combined effect of environment and time reduced the fatigue durability of the adhesive. The longer the aging time in the high temperature environment of 80 ℃, the more significant the impact on the fatigue performance of the joint.
【Keywords】lightweight; adhesive technology; adhesive joint; high temperature environment; fatigue property
Synthesis of β-diketone and its application in metal bonding
Liu Yifan, Liu Yan, Lin Hao, Liu Jian
(School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China)
【Abstract】1-phenylnonane-1,3-diketone (denoted as β-diketone) was prepared by using acetophenone and ethyl heptanoate as raw materials, ethylene glycol dimethyl ether as solution, and sodium ethanol as catalyst, for the study of bonding properties with pretreatment of steel surface and after treatment. The reaction between β-diketone and iron was studied under aerobic and anaerobic conditions, the changes in Fe3+ concentration in the reaction solution and the corrosion on the steel plate surface were tested, and the bonding performance of the steel plate bonding joints before and after treatment with β-diketone was tested. The research results showed that β-diketone was successfully synthesized by structural characterization of Fourier transform infrared spectroscopy (FT-IR) and Fourier digital nuclear magnetic resonance (1H-NMR). Inductively coupled plasma emission spectroscopy analysis showed that coordination bonds could be formed with oxygen atoms in β-diketone after Fe was oxidized into Fe3+, forming chelates. The reaction rate between β-diketone and steel plate was accelerated through cyclic voltammetry and potentio static testing methods. The surface corrosion degree obtained by electrochemical treatment of steel plate for 2 hours was similar to that obtained by treatment at room temperature for 18 hours, therefore electrochemical treatment could be used to improve bonding performance. When the steel plate was treated with β-diketone for 18 hours, the rough surface obtained could form the strong mechanical interlock with the adhesive, the bonding strength increased by 27.0% compared to the original, reaching the highest strength.
【Keywords】β-diketone; surface pretreatment; chelate; mechanical interlock; bonding strength
Study on release amount and content of acrylamide and acrylate residual monomers in adhesive
Sun Wenhui, Liu Xiaoqin, Pan Minxia, Tian Guangchao, He Yihua, Zhao Zhihao, Zhang Lanlan
(GRG Metrology & Test Group Co., Ltd., Guangzhou 510656, Guangdong, China)
【Abstract】The bag method was used to determine the release amount of residual monomers such as acrylamide and acrylate in cured adhesive. The effects of curing time, test temperature, and heating time on the release amount of these two substances were studied. The research results showed that extending the curing time appropriately had a significant effect on reducing the residual monomers of adhesive after curing. When the test temperature in the bag method was 60 ℃, the release amount of residual monomers in adhesive was much greater than the release amount corresponding to the test temperature of 40 ℃, indicating that temperature had a significant impact on the release of residual monomers in adhesive. The different heating time of the air bag could affect the release of residual monomers in adhesive. Therefore, an appropriate heating time should be selected to avoid the situation of undetected or oversaturated residual monomers. By analyzing the release amount and content of residual monomers in various adhesives after curing, it was possible to have a more comprehensive understanding of the composition and environmental performance of various adhesives. The data comparison results indicated that the release amount and content of residual monomers such as acrylamide and acrylate in adhesive were basically positively correlated.
【Keywords】adhesive; acrylamide; acrylate; monomer; release amount; content; bag method
Study on the preparation and properties of acrylate pressure sensitive adhesive
Wang Beibei1, Cao Sheng 2, Cui Ao1, Wang Liya 2
(1.Xi'an Aeronautical Institute, Xi'an 710077, Shaanxi, China; 2.Xi'an Aerospace Sunvalor Chemical Co., Ltd., Xi'an 710089, Shaanxi, China)
【Abstract】Solvent-based acrylate pressure sensitive adhesive with different monomer concentrations and adhesive thickness were prepared by solution polymerization process, using 2-ethylhexyl acrylate as soft monomer, methyl acrylate as hard monomer, acrylic acid as functional monomer, ethyl acetate as solvent, and azodiisobutyronitrile as initiator. The effects of monomer concentration and adhesive thickness on the mechanical properties (loop tack, 180° peel strength and holding power) of acrylate pressure sensitive adhesive were studied. The research results showed that the monomer concentration had little effect on the solid content of acrylate pressure sensitive adhesive. When the monomer concentration was 47.64%, the viscosity was relatively optimal. When the monomer concentration was 47.64% and the adhesive thickness was 30 μm, the acrylate pressure sensitive adhesive with excellent performance and balance among the three properties of loop tack, 180° peel strength and holding power could be obtained.
【Keywords】acrylate; pressure sensitive adhesive; monomer concentration; adhesive thickness; mechanical property
Special Topics and Review
Research progress of high performance polyimide adhesive
Shi Ruixin1, Wu Xiao2, Xu Hui2, Cai Xiulian1, Yu Wenfang1, Wu Mingyue1, Zhu Qingzeng1
(1.Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, Shandong, China; 2.AVIC Research Institute for Special Structures of Aeronautical Composites, Jinan 250023, Shandong, China)
【Abstract】Polyimide has important application prospects in the high-tech field due to its characteristics of excellent high-temperature resistance. In this paper, the research and application progress of high performance polyimide adhesive in recent years were reviewed. The classification of polyimide adhesive and the current status of modification research were analyzed, the introduction of bulk groups, polysiloxanes, active end groups and other methods of structural modification in polyimide were mainly described. The research progress of component modification by combining polyimide with carbon fibers and nano inorganic particles was elaborated, and the development prospects of high performance polyimide adhesive were put forward.
【Keywords】polyimide; modification; adhesive; research progress
Development of cellulose aerogels and their application in dye adsorption
Du Yanli1, Wu Tong2, Zhao Xueyan2, Pei Lu2, Ren Fang2
（1. No.203 Research Institute of Nuclear Industry, Xianyang 712000, Shaanxi, China; 2. Xi'an University of Technology, Xi'an 710048, Shaanxi, China）
【Abstract】The modern printing industry produces a large amount of printing and dyeing wastewater, if directly discharged, it will seriously damage the ecological environment and threaten human health. Among many methods to solve the pollution, adsorption method has attracted the attention of researchers due to its easy operation, low cost and green characteristics of no secondary pollution. Cellulose aerogels have become the focus of research in the field of adsorption due to their large specific surface area, high porosity, excellent biocompatibility, as well as renewable and degradable properties. In this paper, the preparation and modification methods (e.g., hydrophobic modification, chemical modification) of cellulose aerogels were introduced, the research progress on the application of cellulose aerogels in the field of dye adsorption was emphatically discussed, and the development prospect of cellulose aerogels was put forward.
【Keywords】printing and dyeing wastewater; cellulose aerogels; adsorption performance; modification