Special Topics Review
Research progress on compatibility of epoxy asphalt
Qian Dan, Fan Hong
(College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310014, Zhejiang, China)
【Abstract】Epoxy asphalt is a kind of modified asphalt with excellent performance, which has been mainly used in bridge deck paving of large-span bridges, and has a relatively broad market. At present, domestic epoxy asphalt mainly relies on imports and is very expensive, so developing domestically produced epoxy asphalt has been a research hotspot in recent years. Due to the polarity difference between epoxy resin and asphalt, solving compatibility issues is one of the focuses of epoxy asphalt research. In this article, the formation mechanism, compatibility research methods, and compatibilization methods of epoxy asphalt phase separation were mainly reviewed.
【Keywords】epoxy asphalt; compatibility; curing agent; compatibilizer
Development status of sealing technology for deep-sea underwater connector
Gou Haolan1, Qi Liuming2, Fan Hong1
(1.College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, Zhejiang, China; 2. China State Shipbuilding Corporation Limited (CSSC) 715th Research Institute, Hangzhou 310023, Zhejiang, China)
【Abstract】The underwater connector is one of the key universal supporting components for marine equipment, ensuring the supply of energy and transmission of signals for deep-sea detectors in the process of exploring marine resources. In this article, the development history of underwater connector, the types of underwater connectors at home and abroad, the production and manufacturing processes, enterprises and application scenarios were introduced, the research progress of sealing technology between encapsulating insulation materials and metal conductors in underwater connector was emphatically elaborated. Based on the characteristics of materials science, the selection of insulation materials, sealing molding processes, and research progress in three types of underwater connectors, i.e. rubber type underwater connector, glass sintered underwater connector, and plastic type underwater connector were reviewed, providing a reference for the comprehensive understanding of sealing technology in underwater connector. Finally, the future development of underwater connector was prospected.
【Keywords】underwater connector; insulation material; encapsulation process
Research Report
Study on the modification of APAO-V based hot melt adhesive with vinyl triethoxysilane (VTES) and its properties
Hu Yuan, Yang Hong, Li Shijuan, Li Qiuying, Guo Weihong
(School of Materials Science and Engineering, East China University of Science and Technology, Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, Shanghai 200237, China)
【Abstract】A reactive poly alpha olefin vinyl triethoxysilane (APAO-V) based hot melt adhesive with high bonding strength, solvent resistance, and heat stability was prepared by grafting modification of poly alpha olefin (APAO) based hot melt adhesive with vinyl triethoxysilane (VTES). The effects of different mass fractions of VTES modified APAO on the various properties of the prepared hot melt adhesive system were explored, in order to determine the optimal ratio. The research results showed that: ⑴The FT-IR curves indicated that VTES underwent hydrolysis and self-crosslinking, and VTES modified APAO successfully. The XRD diffraction curves indicated that VTES grafted APAO had no effect on its crystal morphology. ⑵ When the mass fraction of VTES was 8%, the softening point and rotational viscosity of VTES modified APAO based hot melt adhesive reached their maximum values, which were 147.7 ℃ and 7 025 mPa·s, respectively. APAO based hot melt adhesive had the best thermal stability performance. ⑶ The reactive APAO-V based hot melt adhesive prepared by modifying APAO with 8% VTES showed improved bonding strength at room temperature, high temperature (60 ℃), and low temperature (-20 ℃), among which the best bonding enhancement effect was at room temperature and the peel strength increased 15.0 N/cm. After being immersed in water for 28 days, the peel strength of the modified hot melt adhesive could still reach 22.3 N/cm. ⑷ The reactive APAO-V based hot melt adhesive prepared by modifying APAO with 8% VTES showed that, the single lap shear strength of hot melt adhesive on four different plastic substrates (PE, PVC, PP, and ABS) was compared, the bonding performance of hot melt adhesive prepared by APAO after modification was greatly improved.
【Keywords】hot melt adhesive; vinyl triethoxysilane; APAO-V based hot melt adhesive; heat resistance; bonding strength
Molecular dynamics simulation of diffusion properties of plasticizers in silicone sealant systems
An Guilei1, Lu Chun1, Chen Bohan2, Qi Wen1
(1.School of Chemistry and Chemical Engineering, Guangxi Minzu University, Key Laboratory of Chemistry and Engineering of Forest Products, State Ethnic Affairs Commission, Guangxi Key Laboratory of Chemistry and Engineering of Forest Products, Guangxi Collaborative Innovation Center for Chemistry and Engineering of Forest Products, Nanning 530006, Guangxi, China; 2.Dalian University of Technology, Dalian 116024, Liaoning, China)
【Abstract】The diffusion properties of three kinds of plasticizers (white oil, methyl silicone oil, and vinyl-terminated silicone oil) in de-ketoxime silicone sealant were analyzed by using molecular dynamics simulation method under the COMPASS II force field. The research results showed that, ⑴ At the same temperature (298 K), the order of diffusion coefficients of plasticizers was: white oil > methyl silicone oil > vinyl-terminated silicone oil. As the temperature increased, the diffusion coefficients of three kinds of plasticizers also increased. When the temperature exceeded 318 K, the diffusion coefficient of white oil increased sharply, and the increase in vinyl-terminated silicone oil was the slowest. As the content of plasticizers increased, the diffusion coefficients of three kinds of plasticizers in the silicone sealant system also increased, and the diffusion ability of plasticizers increased with the increase of their content. ⑵ Among three kinds of blending systems, the compatibility of de-ketoxime sealant/white oil system was the worst, the intermolecular free volume and free volume fraction of the system were the highest, and the occupied volume and size of plasticizer molecules were the largest. The combined effect of these factors led to strong diffusion ability of white oil, while vinyl-terminated silicone oil had good anti-migration ability. ⑶ The increase in temperature weakened the intermolecular interaction between de-ketoxime sealant and plasticizer, while increasing the free volume and free volume fraction of the system, increasing the movement space of plasticizer molecules and improving their diffusion ability. ⑷ The higher the plasticizer content, the greater the interaction energy and van der Waals force interaction energy formed between the molecules of de-ketoxime sealant. However, at the same time, the free volume and free volume fraction of the system also increased with the increase of plasticizer content. The molecular diffusion ability of plasticizers was the result of the mechanical effect and spatial effect of intermolecular interactions.
【Keywords】silicone sealant; mixture; diffusion; dissolution; microscale; molecular simulation; dynamics model
Preparation and performance study of silicone modified composite soft segment of waterborne polyurethane
Liu Mingze, Wei Xiaoli, Zhang Faxing, Shama Nonghua
(Sichuan University of Science and Engineering, Zigong 643000, Sichuan, China)
【Abstract】A new type of waterborne polyurethane (WPU-SiF) emulsion was prepared with hydroxyfluorosilicone oil (FSiO) as raw material, linolenic acid-epoxy diol (LA-ER) and polypropylene glycol 1000 (PPG-1000) as composite soft segment, isophorone diisocyanate (IPDI) and diphenylmethane diisocyanate (MDI) as composite hard segment, and sodium ethylenediaminoethanesulfonate (CA-95) as hydrophilic chain extender. The influence of FSiO content on the performance of WPU-SiF emulsion was also discussed. The research results showed that, ⑴ The infrared spectroscopy analysis confirmed that FSiO was successfully integrated into waterborne polyurethane (WPU) and the target product WPU-SiF was synthesized. ⑵ With the increase of FSiO content, the average particle size of WPU-SiF emulsion gradually increased, the solid content gradually decreased, and the viscosity gradually decreased. The stability of emulsion at room temperature and freeze-thaw was good, and the stability at high temperature was also improved. ⑶ With the increase of FSiO content, the overall trend of pencil hardness of the coating decreased, the glossiness slightly increased, the surface drying time gradually prolonged, the water contact angle of the coating first increased and then decreased, the tensile strength of the adhesive film also increased, and the elongation at break of the adhesive film showed a trend of first increasing and then decreasing. When the FSiO content was 5%, the hydrophobicity of WPU-SiF adhesive film was relatively good, and the water contact angle of the adhesive film was 78.46°. ⑷ In comprehensive consideration, when the FSiO content was 5%, the comprehensive performance of WPU-SiF emulsion was excellent.
【Keywords】silicone; modification; composite soft segment; waterborne polyurethane
Process and Application
Acrylate block copolymer latex empowering high-end pressure sensitive adhesive "oil to water"
Pi Junke1, Fan Xin1, Zhao Hui1, Chen Wendong1, Zeng Ming1, Ge Yuzhou1, Wu Rongsheng1, Luo Yingwu1,2
(1.Entron Advanced Materials Co., Ltd., Shaoxing 312000, Zhejiang, China; 2.Institute of Polymer and Polymerization Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China)
【Abstract】Starting from the relationship between the structure and performance of pressure sensitive adhesive, the design ideas of high-end pressure sensitive adhesive were summarized in this paper. Based on active emulsion polymerization technology, the acrylate block copolymer emulsion was designed and prepared that could meet the requirements of high-end adhesive tape, breaking through the current dilemma of unbalanced performance and poor resistance to moisture and heat in waterborne pressure sensitive adhesive, which is expected to accelerate the process of "oil to water" in high-end pressure sensitive adhesive.
【Keywords】acrylate block copolymer; acrylate emulsion; waterborne pressure sensitive adhesive; pressure sensitive adhesive performance; physical crosslinking
Study on curing process of one-component paste adhesive with high-temperature resistance
Jing Junyi1, Song Caiyu2, Sun Mingming2, Xie Tianyi2, Yu Haoyang2, Zhang Bin2, Wang Hongyang2, Li Jinzi2
（1. AVIC Chengdu Aircraft Design and Research Institute, Chengdu 610091, Sichuan, China; 2. Institute of Petrochemistry, Heilongjiang Academy of Sciences, Harbin 150040, Heilongjiang, China）
【Abstract】One-component paste adhesive J-481 with high-temperature resistance was taken as the research object, the exothermic curve of adhesive J-481 was detected by using differential scanning calorimeter. The viscosity-temperature curve of adhesive sample and the viscosity-time characteristics under different heating processes were investigated by using rheometer. The bonding strength of the adhesive sample under different curing processes and the physical state of the adhesive with different adhesive layer thicknesses after curing under different curing processes were analyzed. The research results showed that, the viscosity, curing degree, and bonding performance of adhesive J-481were significantly affected by the curing mechanism. Excessive heating caused rapid viscosity growth, heat accumulation caused explosive aggregation and ablation of thick adhesive layer samples, and insufficient curing temperature led to a decrease in bonding strength. By using a gradient heating and curing method of 120 ℃/3 h+180 ℃/1 h, all samples with the thickness of 0.3~5 mm could be cured normally without any explosive aggregation or ablation phenomenon, which was more suitable for practical applications. Comparing the curing degree and bonding strength of different substrates under two curing conditions of 120 ℃/3 h+180 ℃/1 h and 180 ℃/3 h, it was found that using the gradient heating and curing mechanism of 120 ℃/3 h+180 ℃/1 h could ensure excellent and stable bonding performance of adhesive J-481 for bonding different substrates.
【Keywords】paste adhesive; construction technology; curing condition
Preparation and properties of hyperbranched polyurethane acrylate adhesive
Xiao Sihao1, Huang Chengshang1, Mei Wei1, Li Quantao2, Xu Zushun1,2
[1. School of Materials Science and Engineering, Hubei University, Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymer Materials, Wuhan 430062, Hubei, China;2.Huda Changhe Technology Innovation (Huzhou) Co., Ltd., Huzhou 313100, Zhejiang, China]
【Abstract】Hyperbranched polyurethane acrylate (HPUA) was prepared by using isophorone diisocyanate, polytetrahydrofuranediol, trimethylolpropane, and hydroxyethyl methacrylate as raw materials. A series of photocuring adhesives were prepared by adding photoinitiators and active diluents, and their structural characterization and thermal stability were studied. The effects of the type of photoinitiator, the ratio of HPUA to the active diluent trimethylolpropane triacrylate (TMPTA), and the amount of siloxane coupling agent (3-aminopropyltriethoxysilane) on the properties of photocuring adhesive were explored. The research results showed that the expected product was successfully prepared, and the synthesized HPUA had excellent thermal stability. When using 3% mass fraction of photo initiator Irgacure1173, m(HPUA): m(TMPTA)=1:1, and adding 3% content of 3-aminopropyltriethoxysilane, the comprehensive performance of the photocuring adhesive was the best. At this time, the tensile shear strength of the adhesive to the glass substrate was 2.15 MPa, the elongation at break was 49.23%, the gelation rate was 98.56%, the volume shrinkage rate was 1.02%, and the Shore hardness was D55.
【Keywords】hyperbranched; polyurethane acrylate; ultraviolet curing; adhesive
Material Science
Preparation of 4-dimethylaminopyridine-boron trifluoride complex type curing accelerator and its catalytic effect on epoxy curing
Dai Shengwei1, Wang Xiaolei1, Zhang Yousheng2, Yang Changxu1, Han Shujun1, Qi Yuexin1, Liu Jingang1
(1. China University of Geosciences Beijing, Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing 100083, China; 2. Zhejiang Jameen New Material Co., Ltd., Jiaxing, 314011 Zhejiang, China)
【Abstract】A complex type of curing accelerator (DMAP-BF) was prepared by using 4-dimethylaminopyridine (DMAP) and boron trifluoride-ether solution [BF3-O(C2H5)2] as the raw materials, and its chemical structure was characterized. The catalytic effects of this curing accelerator on the curing reaction of the ternary composite system (BF-1~BF-6) composed of biphenyl aromatic alkyl epoxy resin (NC3000), naphthalene-containing tetrafunctional epoxy resin (HP4700) and nitrogen-containing phenolic resin (PF8705) were systematically investigated. The research results showed that, ⑴ The expected product was successfully prepared by conducting infrared, nuclear magnetic, XRD, and microscopic morphology analysis on the curing accelerator and epoxy-phenolic aldehyde-curing accelerator premix. ⑵ The curing performance test results indicated that DMAP-BF could catalyze the curing reaction of epoxy-phenolic system and exhibited good thermal latency characteristics. DMAP-BF had a good catalytic effect on the curing of the epoxy-phenolic composite system mentioned above. The activation energy (Ea) of curing reaction of the BF-ref sample without DMAP-BF promoter was 109.4 kJ/mol higher than that of the BF-6 system [m(NC3000): m(HP4700)=50:50]. ⑶ The melt viscosity of the BF sample system in the temperature range of 100-140 ℃ could be as low as 0.1 Pa×s, but when the temperature reached the curing process temperature (175 ℃), DMAP-BF could catalyze the rapid curing of the epoxy-phenolic resin system. This characteristic was crucial for the practical application of DMAP-BF, as it could endow epoxy molding compound (EMC) with better storage stability and process performance. ⑷ The initial thermal decomposition temperature of BF series cured products was around 400 ℃, and the weight loss decreased after 500 ℃, indicating that BF composite cured products had good heat resistance stability and could meet the subsequent application requirements of EMC.
【Keywords】epoxy molding compound; curing accelerator; thermal latency; 4-dimethylaminopyridine; boron trifluoride