Scientific Research Report
Preparation and properties of non-covalently modified graphene epoxy nanocomposites with naphthalene ring
Zhai Ninghui, Cai Xiqing, ZhaoFugui, Zhang Junying, Cheng Jue
(College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China)
【Abstract】The force of dispersion with different structures on graphene was investigated, and the graphene dispersion was characterized by microscope and Raman spectroscopy. It was found that 2-hydroxynaphthalene glycidyl ether (2-NGE) had the strongest naphthalene ring π-π interaction with graphene. Then, 2-NGE suspension chain was introduced into 1,6-dihydroxynaphthalene glycidyl ether (1,6-DNGE), and 4,4'-diaminodiphenylmethane (DDM) was used as curing agent, the effect of "internal anti-plasticization" and the effect of 2-NGE graphene dispersion with different concentrations on the system were investigated. The research results showed that 1,6-DNGE/2-NGE-10%-G5 system exhibited the best comprehensive performance. Compared with 1,6-DNGE, the tensile strength, modulus and impact strength increased by 12.74%, 21.67% and 55.74%, respectively. These excellent properties were achieved based on the construction of the "internal anti-plasticization" system and the good dispersion of graphene, demonstrating that the efficient utilization of high-performance materials was realized under the condition of extremely low graphene loading (0.026 9%). Through this simple and practical method, the rapid and large-scale preparation of high performance graphene epoxy nanocomposites was achieved.
【Keywords】naphthyl epoxy; graphene; internal anti-plasticization; π-π interaction of naphthalene ring
Application of ferrocenium salt as cationic photoinitiator in adhesive
Luo Yicong1, Li Zhiquan1,2, Liu Xiaoxuan1,2
（1. Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter, School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong, China; 2.Guangdong Laboratory of Chemistry and Fine Chemical Industry Jieyang Center, Jieyang 522000, Guangdong, China)
【Abstract】Two types of ferrocenium salt (I-261 and I-262) were used as cationic photoinitiators, the cationic adhesive was successfully cured under 405 nm LED light source. Three types of epoxy monomers were selected, namely bisphenol-A diglycidyl ether (BADGE), 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (CE), 3,3’-[Oxybis(methylene)]bis(3-ethyloxetane) (DOX), their photo curing kinetics were studied under 405 nm LED light source. The photoinitiation properties of different cationic photoinitiators, the initiation efficiency of ferrocenium salt on different cationic monomers, the thermal stability of epoxy resin, the tensile shear properties of cationic light-curing adhesive and the effects of post-curing time on tensile shear strength of adhesive were also investigated. The research results showed that the practicality of ferrocenium salts as photoinitiator for visible light curing adhesive was determined, their initiation efficiency was stronger than that of iodonium salt photoinitiator I-250 under 405 nm LED light source. Using BADGE as the main monomer, the tensile shear properties of photo curing adhesive formed by adding different contents of CE and DOX were studied. It was found that with the adding amount of 40%, the tensile shear strength of the adhesive mixed with CE and DOX was 2.19 times and 1.38 times respectively higher than that of the adhesive polymerized by BADGE, and the tensile shear strength of the adhesive could be significantly improved with the increase of post-curing time. This study provided a practical method for visible light curable cationic adhesive.
【Keywords】ferrocenium salt; visible light curable; cationic adhesive; photo curing kinetics
Synthesis and properties of fluorine-containing diaminophthalonitrile resin
Liu Caizhao, Li Shuaijie, Zhang Bin, Sun Mingming, Zhang Xugang, Li Jianhui
(Institute of Petrochemistry Heilongjiang Academy of Sciences, Harbin 150040, Heilongjiang, China)
【Abstract】A kind of fluorine-containing diaminophthalonitrile resin (FPN-p) was prepared by nucleophilic substitution reaction using 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane and 4-nitrophthalonitrile as raw materials. Its chemical structure was characterized by Fourier infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H-NMR), the curing behavior of the resin was investigated by differential scanning calorimetry (DSC) and FT-IR, and the thermal stability, thermal mechanical properties and moisture heat resistance of the resin were also studied. The research results showed that FPN-p resin could realize autocatalytic polymerization without accelerator, and the product structure was mainly composed of triazine ring and phthalocyanine ring. The glass transition temperature and thermal decomposition temperature with 5% mass fraction of the resin both exceeded 400 ℃, indicating a high temperature resistance level. The resin had good moisture heat resistance, the water absorption rate was less than 1% after 168 hours of high-temperature water boiling. The resin was expected to be used in fields such as high-temperature resistance coatings, resin based composites, and high performance adhesive.
【Keywords】diamino group; phthalonitrile; resin; thermal property; water absorption rate
Development of epoxy resin adhesive for agricultural machinery maintenance
Wang Donglin, Li Shouzhong
(College of Engineering, China Agricultural University, Beijing 100083, China)
【Abstract】With amino-terminated liquid acrylonitrile-butadiene rubber (ATBN) and silane coupling-treated aluminum powder as modifiers, epoxy resin adhesive for quick repair of agricultural machinery was prepared. The effects of aluminum powder and ATBN dosage on the bonding properties of adhesive were investigated. The research results showed that the pot life of epoxy resin adhesive was prolonged with the increase of aluminum powder using amount. With the continuous increase of aluminum powder dosage or ATBN dosage, the bonding strength of adhesive on aluminum alloy was increased first and then decreased. When the using amount of aluminum powder and ATBN was 20 and 15 phr respectively (relative to the mass of 100 phr epoxy resin), the comprehensive performance of epoxy resin adhesive was relatively good, its pot life was 37 min, tensile shear strength and floating roll peel strength were 29.5 MPa and 5.4 kN/m respectively. The adhesive had excellent medium resistance and heat resistance, which could be used not only for daily maintenance of agricultural machinery, but also for structural bonding of various metallic and non-metallic materials in other fields.
【Keywords】epoxy resin; adhesive; room temperature curing; agricultural machinery; maintenance
Preparation and properties of solvent-resistance emulsion-type acrylate pressure sensitive adhesive
Chen Jie, Pei Kemei
(Zhejiang Sci-Tech University, Hangzhou 310020, Zhejiang, China)
【Abstract】Acrylate pressure sensitive adhesive was prepared by seed emulsion polymerization using epoxy resin and acrylate monomer as raw materials. The effects of hard monomer type and content, soft monomer ratio, functional monomer content, initiator content and seed emulsion content on the bonding properties of pressure sensitive adhesive were studied. The research results showed that among 8 types of hard monomer, the performance of epoxy resin E-20 was relatively optimal. When its addition amount was 2.5% by mass (relative to the total mass), the soft monomer was 2-ethylhexyl acrylate (2-EHA) and the mass fraction was 35%, the mass fraction of functional monomer b-carboxyethyl acrylate (β-CEA) was 10%, the mass fraction of initiator was 0.5%, the mass fraction of seed emulsion was 5%, and the mass fraction of buffer agent was 0.5%, the prepared pressure sensitive adhesive had good performance, the peel strength was 15.10 N/25 mm, the holding power was greater than 48 h, and the solvent resistance was excellent.
【Keywords】acrylate; pressure sensitive adhesive; emulsion polymerization
Development and Application
Study on reinforcement performance of modified epoxy resin adhesive in underground steel frame structure of building
Zhao Hongmei, Zhang Shipin
(China Nuclear Industry Huawei Engineering Design and Research Co., Ltd., Nanjing 210000, Jiangsu, China)
【Abstract】The composite epoxy resin adhesive for building reinforcement was prepared with epoxy resin, curing compound, accelerator, filler and coupling agent as main preparation materials, mixed with different kinds or contents of them, and modified by self-made graphene oxide. 45# steel sheet specimen was prepared, and the mechanical indexes, gel time and other indexes of the specimen coated with adhesive were tested respectively, and the reinforcement effect of epoxy resin adhesive with different proportions in the underground steel frame structure of building was analyzed. The research results showed that the tensile, flexural and compressive strength of epoxy resin adhesive could be improved by selecting E-51 as main resin, and the tensile resistance of epoxy resin adhesive was the best when it was mixed with curing agent at the mass ratio of 75∶100. The mechanical properties of epoxy resin adhesive could be improved effectively when the mass addition amounts of curing agent, accelerator and filler were 30%, 4% and 80% respectively, and KH-570 was used as coupling agent. After adding 2.0% graphene oxide, the tensile strength and elongation at break of composite epoxy resin adhesive reached the maximum. In the humid environment, the composite epoxy resin adhesive could be fully cured after about 65 hours, and the shear bonding strength was stable at 20 MPa.
【Keywords】epoxy resin adhesive; steel frame; reinforcement effect; graphene oxide; tensile resistance; shear bonding strength
Application of waterproof concrete in crack filling of tunnel secondary lining
Song Jianing, Zeng Qingwei, Wang Andong
(Shaanxi Railway Institute, Weinan 714000, Shaanxi, China)
【Abstract】Waterproof concrete samples were prepared by mixing cement, fly ash and waterproof agent in a certain ratio. The application effect of waterproof concrete in crack filling of tunnel secondary lining was tested, and various properties such as impermeability and crack resistance of waterproof concrete in crack filling of tunnel secondary lining were studied. At the same time, the microstructure of building materials in crack filling of tunnel secondary lining before and after drying was observed. The research results showed that in the application of crack filling of tunnel secondary lining, fly ash helped to increase the impermeability of concrete, and an excess replacement ratio between 15% and 25% was suitable. When the water cement ratio was high, adding an appropriate type of waterproof agent could improve the impermeability performance. When the water cement ratio was low, there was no need to add waterproof agent to the concrete. Under the same replacement ratio of fly ash, concrete with excessive replacement had good resistance to chloride ion diffusion. Fly ash could avoid early cracking of concrete, and concrete with different fly ash ratios had the characteristics of later cracking time and narrower crack width. The microstructure of the concrete added with fly ash exhibited dense fine needle bar ettringite crystals, the concrete had strong tensile strength after the drying test.
【Keywords】fly ash; concrete; waterproof agent; crack filling; water pressure impermeability; secondary lining; crack resistance
Simultaneous determination of multiple compounds in water-based adhesive
Yang Fei1, Zhou Yun2, Zhang Yupu3, Ju Huabo4, Yan Jun2, Meng Dongling2, Deng Huimin1, Tang Gangling1, Chen Zhiyan1
（1. China National Tobacco Quality Supervision & Test Center, Zhengzhou 450001, Henan, China; 2. China Tobacco Guangxi Industrial Co., Ltd., Nanning 530001, Guangxi, China; 3. Jilin Tobacco Quality Supervision & Test Station, Changchun 130062, Jilin, China; 5. Northwest Tobacco Quality Supervision & Test Station, Lanzhou 730030, Gansu, China)
【Abstract】A method was developed for the simultaneous determination of isothiazolinone fungicides and environmental hormones such as bisphenol A, nonylphenol, octylphenol and phthalate in water-based adhesive. After methanol extraction, the sample was directly analyzed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and quantified by isotope internal standard method. The research results showed that all compounds showed good linearity (R2≥0.998 3) within the concentration range of 20~500 ng/mL, and the limit of detection (LOD) and limit of quantification (LOQ) were in the range of 0.009~0.115 mg/kg and 0.029~0.382 mg/kg, respectively. At different concentration levels, the recovery rates of all analytes were in the range of 84.1% to 105.6%, the daytime relative standard deviation (RSD) was less than 8.0%. Sixty actual samples were tested, all samples detected isothiazolinone fungicides, and one sample each detected nonylphenol and dibutyl phthalate. This method had high detection efficiency and saved detection costs, especially suitable for routine detection of large batches of samples in the laboratory.
【Keywords】water-based adhesive; ultra-high performance liquid chromatography-tandem mass spectrometry; bisphenol A; alkylphenol; phthalate; isothiazolinone
Influence of weathering test on infrared spectrum of insulating glass sealants
Wang Longmei, Yao Yongxin, Zhou Lei, Huang Xinhang
(Shanghai Institute of Quality Inspection and Technical Research, Shanghai 201114, China)
【Abstract】The weathering test of insulating glass sealants was carried out under four conditions of high humidity, high and low temperature, climate and ultraviolet radiation. The attenuated total reflection (ATR) method was used to test the infrared spectrum of sealants before and after weathering test, the effects of different test conditions on the infrared spectrum of silicone sealant, polysulfide sealant and polyurethane sealant for insulating glass were analyzed. The research results showed that the position of infrared spectrum absorption peak of insulating glass sealants had no obvious change after four kinds of weathering test. After the high humidity test, the intensity of infrared absorption peak decreased, with silicone sealant showing the most significant decrease. After the high and low temperature test, the infrared spectrum remained basically unchanged. After the climate test and ultraviolet irradiation test, the infrared spectrum of silicone sealant did not change, the intensity of the main absorption peaks of polysulfide sealant decreased significantly, and the intensity of other absorption peaks of polyurethane sealant increased except for the decrease of intensity of the absorption peak near 1 407 cm-1. The change of infrared spectrum of sealants after weathering test showed that three sealants had excellent high and low temperature resistance, among which silicone sealant had the worst moisture resistance and polyurethane sealant had the best, meanwhile silicone sealant had the best UV radiation resistance and polysulfide sealant had the worst.
【Keywords】weathering test; silicone sealant; polysulfide sealant; polyurethane sealant; infrared spectrum
Study on preparation and properties of dealcoholized photovoltaic module sealant
Wen Renguang, Chu Saixia
（Shenzhen SISUN Silicone Technology Co., Ltd., Shenzhen 518107, Guangdong, China）
【Abstract】Using a,w-dihydroxypolydimethylsiloxane, dimethylpolysiloxane, reinforcing filler, thixotropic agent, coupling agent and catalyst as raw materials, adding self-made multifunctional telechelic oligosiloxane crosslinking agent and modified siloxane tackifier, a kind of dealcoholized silicone sealant suitable for durable bonding of photovoltaic module was prepared. Different types, structures and using amounts of tackifier and crosslinking agent on the properties of dealcoholized silicone sealant were studied. The research results showed that when the mass fraction of a,w-dihydroxypolydimethylsiloxane was 100 parts, the mass fraction of dimethylsiloxane was 10 parts, the mass fraction of multifunctional telechelic oligosiloxane crosslinking agent with R of —(OCH3) and m=4 was 5 parts, the mass fraction of reinforcing filler was 120 parts, the mass fraction of thixotropic agent was 5 parts, the mass fraction of modified siloxane tackifier with n=4 was 2 parts, the mass fraction of coupling agent was 3 parts, and the mass fraction of catalyst was 2 parts, the prepared dealcoholized silicone sealant had relatively optimal performance, with high deep curing and excellent adhesive strength. After multiple aging tests, it could still maintain excellent bonding strength, which could meet the continuous use of photovoltaic module in harsh environment, meeting the application requirements of photovoltaic module sealant.
【Keywords】dealcoholized sealant; photovoltaic module; tackifier; crosslinking agent; anti-aging
Special Topics and Review
Research progress on low-temperature curing conductive silver paste system
Miao Xiangsen, Sun Ying, Zhang Xueqin
(School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, Jiangsu, China)
【Abstract】Low-temperature curing conductive silver paste, as key functional material for the preparation of electronic components, has excellent properties such as electrical conductivity, hardness, adhesion and bending resistance after curing, and has been widely used in the field of electronic information industry. In this paper, the compounding of silver powder with different morphologies and sizes in low-temperature curing conductive silver paste system, the properties of organic resin, solvent and common additive on its properties were reviewed, some application of this system in the field of conductive adhesive was listed. The higher application requirements of low-temperature curing silver paste in future electronic information industry were prospected.
【Keywords】compounding of silver powder; nano silver powder; organic resin; conductive silver paste; conductive adhesive