Special Topics Review
Research progress of high viscosity modified asphalt and its application in road engineering
Shi Zhongbao, Shi En, Wang Yuxiao, Ji Jiajun, Li Junhui, Li Qingxu, Zhang Zengping
(Key Laboratory for Special Area Highway Engineering of Ministry of Education, Chang’an University, Xi’an 710064, Shaanxi, China)
【Abstract】In the face of challenges posed by heavy traffic and extreme climates on road engineering, high viscosity modified asphalt has become a key material for enhancing pavement durability and service life due to its excellent viscoelastic properties. The progress in material design, preparation process, performance evaluation, and engineering application of high viscosity modified asphalt was reviewed systematically in this paper. In terms of material composition, the high temperature rutting resistance, low temperature cracking resistance, and water stability of asphalt were significantly enhanced through a composite modification system (such as the synergistic effect of polymers, rubber powder, and fibers). In terms of preparation process, the technical advantages of shear method over direct casting method were elucidated, and energy consumption was reduced through process parameter optimization. In terms of performance evaluation, the evolution laws of material properties were revealed based on multi-scale rheological indicators and aging simulation experiments, guiding their standardized application in scenarios such as drainage pavement, ultra-thin wearing layer, and bridge deck pavement. It was also pointed out in the study that high viscosity modified asphalt currently faced challenges such as high energy consumption, long-term aging performance degradation, and high cost. In the future, it was necessary to promote the development of low-carbon, high-efficiency, and long-life direction through the development of green modifiers, nano reinforcement technology, and intelligent warm mixing strategies, thereby providing theoretical support for the technological upgrading of road engineering materials.
【Keywords】high viscosity modified asphalt; process optimization; multi-scale evaluation; engineering application
Research Report
Synthesis of coumarin-carbazole-based oxime ester photoinitiator and its application in adhesive
Liu Jin , Li Zhiquan, Liu Xiaoxuan
(School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong, China)
【Abstract】A novel coumarin-carbazole-based oxime ester photoinitiator (OXE-BM) was designed and synthesized in this study. By introducing γ,δ-unsaturated double bonds, the effective conversion of low activity imine radicals to high activity methylene radicals was achieved, solving the problem of insufficient imine radical activity in traditional oxime ester photoinitiators. The research results showed that, ⑴ Multiple characterization techniques have confirmed that OXE-BM had a unique "dual radical" initiation mechanism: imine radicals generated by photolysis could be cyclized with unsaturated double bonds within the molecule to generate highly active methylene radicals, while methyl radicals were generated through photo induced decarboxylation pathway, significantly improving the initiation efficiency. ⑵ The absorption spectrum of OXE-BM was red-shifted by 29 nm compared to commercial photoinitiator (OXE-02), extending beyond 400 nm, effectively matching 365-405 nm LED light sources. In the photopolymerization kinetics experiment, its initiation performance was significantly better than OXE-02. ⑶ OXE-BM had moderate thermal stability (221 ℃) and excellent solubility, and the optimal addition amount in polyurethane acrylate (PUA) adhesive was 1.0%, which could achieve the highest bonding strength (about 460 N). ⑷ The molecular design strategy of photoinitiator proposed in this study provided a new idea for developing efficient long-wave photoinitiators, which had important application value in fields such as photo curing adhesive, 3D printing materials, and electronic packaging.
【Keywords】photocuring; oxime ester photoinitiator; photocyclization
Development of silicone pressure sensitive adhesive for extremely low temperature environments
Liu Yangfei, Yao Minshan, Wang Xinyuan, Liu Hao
(State Key Laboratory of Advanced Fiber Materials, Center for Advanced Low-Dimension Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China)
【Abstract】Using methylphenylvinyl silicone oil as the base adhesive, an adhesive solution was prepared by introducing crosslinking agent, MQ silicone resin, platinum-containing catalyst, and toluene solvent. After coating on polyimide film and high temperature curing, the silicone pressure sensitive adhesive tape with the thickness of about 60 μm was obtained. The effect of hydrogen content, silicon hydrogen ratio of hydrogen-containing silicone resin, as well as MQ silicone resin type and addition amount on the 180° peel strength, initial tack, and holding power of pressure sensitive adhesive was systematically studied. The research results showed that when the viscosity of methylphenylvinyl silicone oil was 4 000 mPa·s, the hydrogen content of hydrogen-containing silicone resin was 0.25%, the silicon hydrogen ratio was 1.3:1, MQSN was selected as the reinforcing filler, and its addition amount was 140% of methylphenylvinyl silicone oil, the comprehensive performance of pressure sensitive adhesive was relatively optimal. Its 180° peel strength could reach 7.03 N/25 mm, with the initial tack of 30# small ball and the holding force of over 99 hours. This pressure sensitive adhesive had excellent high and low temperature resistance and could meet the needs of wide temperature range applications. This study provided a theoretical basis for the formulation design and performance optimization of high performance silicone pressure sensitive adhesive.
【Keywords】silicone pressure sensitive adhesive; high and low temperature resistance; phenyl group; silicon hydrogen addition
Preparation and properties of moisture curing PUR hot melt adhesive based on bio raw materials
Liang Chengxu, Huang Yiping
(Anhui Key Laboratory of Green Polymer Materials, School of Chemistry and Chemical Engineering, Anhui University, Hefei 230601, Anhui Province, China)
【Abstract】A series of moisture curing reactive polyurethane (PUR) hot melt adhesive with different ratios of polyether/polyester were prepared by using bio-based raw materials such as polytrimethylene ether glycol (PO3G) and polyethylene terephthalate (PBA) as soft segments and 4,4'- diphenylmethane diisocyanate (MDI) as hard segments, and their mechanical properties, thermal properties, bonding properties, and resistance to moisture and heat aging were characterized. The research results showed that when isocyanate content to hydroxyl content (R value) was 1.5 and the mass ratio m(PO3G)∶m(PBA) was 3:7, the bio-based moisture curing PUR hot melt adhesive sample prepared had excellent performance, with the maximum tensile strength of 28.7 MPa. At this time, PUR had the lowest polydispersity index (up to 1.88), stable physical and chemical properties, and good bonding properties and construction performance. The thermal decomposition temperature of self-made PUR products was higher than 200 ℃, and the heat resistance was good. The self-developed bio-based PUR hot melt adhesive was comparable to the commercially available PUR adhesive in terms of adhesion and aging resistance. It significantly improved the shear strength of multiple substrates under cold and hot cycles and high temperature and humidity, especially for ABS, iron and other materials with excellent wet heat stability. The interface bonding mechanism was more robust, effectively suppressing wet heat debonding. In the future, it was expected to prepare more excellent performance bio-based moisture curing PUR hot melt adhesive by changing the proportion of different types of bio-based raw materials and blending raw materials.
【Keywords】bio-based; moisture curing; PUR hot melt adhesive
Preparation and properties of phenolic resin adhesive modified by fast pyrolysis of bio-oil
Zhang Ziqi, Deng Xiaoshan, Ma Junyao, Jiang Jiongcen, Gong Jiaying, Jia Liangyuan
(School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009, Anhui, China)
【Abstract】Using fast pyrolysis technology to pyrolyze poplar wood to obtain bio-oil (BO), BO was then added to phenolic resin (PF) for modification. A BO-phenolic resin composite adhesive was synthesized by semi synthetic method, and its properties and physicochemical properties were characterized and discussed. Using gas chromatography-mass spectrometry (GC-MS) technology to determine the main componentsin pyrolyzed bio-oil, especially phenolic substances that played a key role in the modification of phenolic resin.The prepared bio-oil-phenolic resin adhesive was tested for viscosity, pH, curing amount, water absorption rate, infrared detection, thermogravimetric analysis, and X-ray diffraction analysis. The research results showed that, ⑴ The viscosity, pH, and solid content of phenolic resin adhesive modified with bio-oil decreased with the increase of bio-oil addition ratios. The water absorption rate of phenolic resin modified with different ratios of bio-oil was not significantly different, but it was higher than that of pure phenolic resin adhesive. In summary, bio-oil modified phenolic resin adhesive had lower viscosity, stronger acidity, lower solid content, and higher water absorption rate. ⑵ The tensile strength of modified adhesive showed a trend of first increasing and then decreasing with the increase of bio-oil addition ratios. When m(BO)∶m(PF)=2∶8, the modified adhesive exhibited the best mechanical properties, with the tensile strength of 7.534 MPa, which was about 36% higher than pure phenolic resin. Therefore, adding an appropriate amount of bio-oil could promote the bonding performance of phenolic resin. ⑶ The carbonization temperature (523 ℃) of bio-oil modified phenolic resin with m(BO)∶m(PF)=2∶8 was only 10 ℃ lower than that of pure phenolic resin, therefore it had good thermal stability. ⑷ The main structure of adhesive formed by adding bio-oil in different proportions was similar to that of pure phenolic resin adhesive. However, after mixing bio-oil with phenolic resin adhesive, most of its functional groups underwent changes and the activity of the substance was significantly reduced. Among them, the infrared spectrum of m(BO)∶m(PF)=2∶8 was most similar to that of pure phenolic resin, indicating that their structures were similar and both had excellent properties. ⑸ The addition of bio-oil had a certain effect on the modification of phenolic resin adhesive. The crystals formed after curing of the prepared modified adhesive were all amorphous crystals. When m(BO)∶m(PF)=2∶8, the diffraction peak intensity was the highest, and it was easier to crystallize after curing, which was more conducive to the bonding of wood.
【Keywords】phenolic resin; adhesive; fast pyrolysis; bio-oil; modification
Process and Application
Study on VOCs removal mechanism of waterborne polyurethane adhesive by vacuum rotary evaporation
Xia Zhiyuan, Liang Guiping, Li Zhenmei, Wan Jing, Yang Dongxiao, Ye Daiyong
(School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China)
【Abstract】In order to prepare waterborne polyurethane-acrylate composite adhesive (WPUA) with ultra-low VOCs, methyl methacrylate was partially used instead of acetone to reduce the viscosity of polyurethane prepolymer during the synthesis process, and co-modified in the dispersion to improve the adhesive performance. The mass transfer equation for the vacuum rotary evaporation process was established, analyzed computationally, and optimized to investigate the effects of rotation speed, volume, and temperature on mass transfer. The research results showed that, ⑴ The synthesized WPUA adhesive had 180° peel strength of 2.57 N/mm and 2.81 N/mm on ABS board and steel plate, respectively. At the same time, the lap shear strength test conducted on ABS spline also showed tensile shear strength of 3.364 MPa, which had good bonding performance on other substrates. The above indicated that WPUA adhesive had a wide range of applicability in various practical application scenarios. ⑵ During the vacuum rotary evaporation process, the synergistic effect of heating and steam stripping could significantly enhance the removal efficiency of VOCs. According to the difference method and gas chromatography analysis, the VOCs content was less than 10 g/L, far lower than that of commercially available products. The shear strength was equivalent to that of commercially available products, but the peel strength was significantly higher. ⑶ The new waterborne polyurethane adhesive synthesized in this study had excellent bonding performance and extremely low VOCs content.
【Keyword】waterborne polyurethane; adhesive; VOCs; mass transfer
Study on development and properties of a thermoplastic spacer butyl sealant for insulating glass
Huang Shiwen1,2, Wu Songze3, Chen Jianjun2,3, Sun Taolin1, Huang Hengchao2
（1.South China University of Technology, Guangzhou 510641, Guangdong, China; 2.Guangzhou Baiyun Technology Co., Ltd., Guangzhou 510540, Guangdong, China; 3.Guangdong Baiyun Technology Co., Ltd., Foshan 528143, Guangdong, China)
【Abstract】A thermoplastic spacer sealant for insulating glass was prepared by modifying butyl hot melt adhesive with silane modified polyolefin, compounding with nano calcium carbonate and carbon black. The effects of the amount of silane modified polyolefin, polyisobutene, nano calcium carbonate and carbon black on the mechanical properties, processing properties, water resistance and aging resistance of silane modified butyl hot melt adhesive were studied. The research results showed that, ⑴ The effect of the amount of silane modified polyolefin/polyisobutene on butyl hot melt adhesive was explored from the aspects of melt index, mechanical properties, interface bonding failure area, aging resistance, and water vapor transmission rate. It was found that the appropriate amount of silane modified polyolefin in the formulation system was 10-20 parts. ⑵ The modified material had improved the thermal stability of the sample in practical use (≤90 ℃). ⑶ When the total amount of nano calcium carbonate/carbon black was constant, the mechanical properties of the material decreased as the value of nano calcium carbonate/carbon black increased, while the melt index increased as the value of nano calcium carbonate/carbon black increased. In order to meet the requirements of good processing performance, mechanical properties, and zero interface damage area for butyl hot melt adhesive, m(nano calcium carbonate)∶m(carbon black)=30∶20 was selected. ⑷ Based on the mechanical properties, construction performance, and aging performance of the above formula, the preferred formula for thermoplastic spacer butyl sealant for insulating glass was 30 parts of polyisobutene, 20 parts of silane modified polyolefin, 20 parts of carbon black, and 30 parts of nano calcium carbonate. A thermoplastic spacer sealant for insulating glass with performance indicators that met the requirements of T/ZBH 024—2023 was prepared.
【Keywords】silane modified polyolefin; butyl hot melt adhesive; aging resistance; insulating glass
Lifetime prediction of side window adhesive for high-speed rail based on activation energy calculation under multiple environmental stresses
Qian Xiumin1, Li Yong1, Li Dongdong2, Li Ying2, Zhang Lanlan2
(1.CRRC Changchun Railway Vehicles Co., Ltd., Changchun 130062, Jilin, China;
2.GRG Metrology & Test Group Co., Ltd., Guangzhou 510700, Guangdong, China;)
【Abstract】In order to evaluate the impact of environmental stress on the performance of side window adhesive for high-speed rail and predict its service life, five different brands of adhesive were selected in this study. Firstly, single environmental stress assessment during use was conducted to identify the sensitive stress factors affecting the adhesive. Based on sensitive stress and use environment, three types of adhesive were subjected to the 1 000 h (70 ℃, 95%RH) damp heat aging test, while the other two types of adhesive were subjected to the combined 1 000 h damp heat and light aging test. By comparing the changes in physical properties of adhesive before and after aging, the specific impact mechanisms of different environmental factors on adhesive properties were revealed. The research results showed that sample 254 adhesive had the highest expected lifespan and exhibited the best durability, making it suitable for high demand application such as side windows for high-speed rail. On this basis, a lifetime prediction model for adhesive was constructed, and the expected service life of each adhesive was obtained, providing important reference information for the selection and maintenance of side window materials for high-speed rail.
【Keywords】adhesive; Peck model; lifetime prediction; accelerated testing
Material Science
Preparation of self-initiating waterborne polyacrylate and its application in cathodic electrophoretic coatings
Wu Shufang, Yang Zhuotao, Liu Xiaoxuan
(School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong, China)
【Abstract】This study aims to develop a novel photocurable self-initiating waterborne polyacrylate to improve the problems of organic solvent volatilization and environmental pollution associated with traditional polyacrylate coatings. By introducing photosensitive groups into the side chains of waterborne polyacrylate, the self-initiating waterborne polyacrylate resin was successfully prepared. This material could rapidly cure under ultraviolet light irradiation, forming a crosslinked structure with certain hardness, thereby solving the migration problem caused by the need for external initiators in traditional waterborne polyacrylate. By adjusting hydrophilic groups such as dimethylaminoethyl methacrylate (DMAEMA), soft segments such as n-butyl acrylate (n-BA), the molar ratios of isophorone diisocyanate-hydroxyethyl acrylate (IPDI-HEA) and hydroxyethyl methacrylate (HEMA), as well as the content of self-initiating groups, the properties of the self-initiating waterborne polyacrylate resin prepared could be controlled and characterized. The research results showed that,⑴ IPDI-HEA and photocurable polyacrylate resin were successfully synthesized. ⑵ When the content of DMAEMA gradually increased, the emulsion state changed gradually from milky yellow to milky white, demonstrating good storage performance. The particle size of the emulsion gradually decreased, and the distribution became more uniform. The coated surface gradually changed from a slightly orange-peel texture to a smooth and flat state, with the hydrophilicity of the cured film significantly improved. ⑶ As the content of soft segments gradually increased, the emulsion state, storage stability, and adhesion showed no significant changes. However, the hardness of coating film exhibited a certain degree of decline. The thermal stability of polyacrylate resin decreased as the proportion of soft segments increased. ⑷ With the gradual increase in the ratio of n(IPDI-HEA)∶n(HEMA), the stability of the emulsion had relatively limited changes, while the hardness of the coating film showed a progressive upward trend. The resistance to acetone wiping also improved, and the adhesion remained consistently at an excellent level, and both the storage modulus (G') and the gelation rate exhibited a gradual increasing trend. ⑸ With the increase in the content of self-initiating groups, both the reaction rate of double bonds and the final conversion rate were improved, reaching a threshold when the self-initiating group content reached 3.0%. ⑹ The electrophoretic coating produced in this study was smooth and flat, featuring low water absorption, superior light transmittance, aging resistance, acid-base resistance, and salt spray resistance, meeting the standard requirements of metallic paint.
【Keywords】self-initiating; waterborne polyacrylate; cathodic electrophoresis; coating; photocurable