Scientific Research Report
Preparation and performance study of high temperature resistance pressure sensitive adhesive for protective film
Wang Hu1, Hu Wei2, Lin Kehua3, Chen Qihui1, Hong Maochun1, Fu Heqing1,2
(1.Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, Fujian, China; 2.School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China; 3.Fujian Youyi Adhesive Tape Group Co., Ltd., Fuzhou 350300, Fujian, China)
【Abstract】With butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA), methyl methacrylate (MMA), and lauryl acrylate (LA) as raw materials, β-carboxyethyl acrylate (β-CEA) as internal crosslinking agent, γ-methacryloxypropyl trimethoxysilane (KH-570) as modifier, trimethylhexamethylene diisocyanate (TMDI) as curing agent and ethyl acetate as solvent, a kind of solvent-based acrylate pressure sensitive adhesive with high performance and high temperature resistance for protective film was prepared. The effects of addition amount of internal crosslinking agent β-CEA, modifier KH-570, monomer LA and curing agent TMDI on the performance of pressure sensitive adhesive for protective film were investigated. The research results showed that when the addition amount of β-CEA was 5%, the water contact angle of pressure sensitive adhesive for protective film was 75.2°, and the wetting performance was the best. When the addition amount of KH-570 was 2.5%, the water absorption rate of pressure sensitive adhesive for protective film was the lowest as 3.5%. With the increase of the content of monomer LA and curing agent TMDI, the high temperature resistance of pressure sensitive adhesive for protective film was significantly improved. In the formula, when w(β-CEA)=5%, w(KH-570)=2.5%, w(LA)=7% and w(TMDI)=2.0%, the water contact angle of pressure sensitive adhesive for protective film was 75.2°, the water absorption rate was 3.5%, the initial tack was No.6 ball, the holding power was 24 h, 180°peeling force was 4.0 N/25 mm, there was no residual after 8 h at 100 ℃, and it was not foamed at 80 ℃ and 90%RH for 100 h.
【Keywords】pressure sensitive adhesive; high temperature resistance; acrylate; protective film
Preparation and curing properties of new tetrafunctional epoxy resin derived from bisphenol S
Yang Zhijian1, Li Kun1, Fan Kefan1, Zhao Fugui1, Zhao Weiwei2, Cheng Jue1, Zhang Junying1
（1. Key Laboratory of Carbon Fiber and Functional Polymer, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, China; 2. Heterostructure Multi-Interface EFS Bonding & Encapsulation Technology Joint Laboratory, AVIC Research Institute for Special Structures of Aeronautical Composites, Ji’nan 250023, Shandong, China）
【Abstract】Tetrafunctional epoxy resin has good temperature resistance and excellent mechanical properties because of its high crosslinking density, among which AG-80 is the matrix resin of high-performance composite material with good comprehensive performance. However, the structural characteristics of AG-80 lead to problems such as poor toughness, high viscosity, unstable storage, and limited degree of crosslinking, which to a certain extent limits the use process and curing performance of AG-80. In order to solve these problems, a new type of tetrafunctional epoxy resin — bisphenol S tetrafunctional glycidyl ether (SEP) was designed and synthesized by two-step method in this paper. The structure of SEP was determined by infrared, nuclear magnetism resonance, mass spectrometry, and the curing behavior of SEP and the properties of cured product were analyzed by differential scanning calorimeter, thermo mechanical analyzer, dynamic thermo mechanical analyzer, thermogravimetric analyzer, etc.. The research results showed that: (1)Compared with AG-80, the viscosity of SEP epoxy resin was lower at 25 ℃, as 52.56 Pa·s, indicating that SEP epoxy resin had better processing flowability. When methyl hexahydrophthalic anhydride was used as the curing agent, the curing temperature of SEP was lower than that of AG-80 epoxy resin, and storage was more stable. (2)A comparative study was conducted on the properties of SEP and AG-80 modified bisphenol A epoxy resin (E-51). When the mass fraction of SEP was 30% (SEP-30), its tensile strength reached 85.77 MPa and impact strength reached 18.74 kJ/m2. The tensile strength and impact strength of AG-80 at the same curing temperature were 68.25 MPa and 12.61 kJ/m2, respectively, indicating that the tensile strength and impact strength of SEP system were higher than those of AG-80 system. Through SEM cross-sectional morphology, it was further determined that the SEP blending system had better mechanical properties than the AG-80 system. (3)The Td5 of all SEP blending systems was higher than that of AG-80 system. The maximum carbon residue rate of SEP system at 800 ℃ was 16.9%, while the maximum carbon residue rate of AG-80 system at 800 ℃ was 9.9%, indicating that SEP had better thermal stability than AG-80. (4)Compared with AG-80 epoxy resin, SEP epoxy resin exhibited better mechanical and heat resistance properties, which provided the possibility of achieving reinforcement and toughening simultaneously, and had the potential to be widely used in high-temperature fields such as aerospace.
【Keywords】tetrafunctional epoxy resin; mechanical property; thermal stability; methyl hexahydrophthalic anhydride
Preparation and properties of biomimetic polyaspartamide derivative adhesive
Liu Hua1, Cai Guidi1, Wang Bo2
(1. Shandong Hongxu Chemical Co., Ltd., Dongying 257200, Shandong, China;2. Jilin Provincial Key Laboratory of Straw-Based Functional Materials, Institute for Interdisciplinary Biomass Functional Materials Studies, Jilin Engineering Normal University, Changchun 130012, Jilin, China)
【Abstract】The development of bio-adhesive for tissue fixation and wound care still remains a challenge. In this study, three different combinations of dopamine (DOPA), ethanolamine (EA) and hydrophobic amino octane (OA) were introduced, polyaspartamide derivatives were first synthesized by using polysuccinimide as the matrix, and then polyaspartamide derivatives PolyAspAm(DOPA/EA) and PolyAspAm(DOPA/OA/EA) adhesive were prepared through continuous ammonolysis reaction. The research results showed that: (1) The tensile shear strength of PolyAspAm(DOPA/EA) adhesive with different water contents on glass substrate was quite different, and the tensile shear strength increased with the decrease of water content. When the water content of PolyAspAm(DOPA/EA) adhesive decreased to 7%, the tensile shear strength increased significantly to 0.6 MPa. (2) The tensile shear strength of PolyAspAm(DOPA/OA/EA) adhesive on different substrates was greater than that of PolyAspAm(DOPA/EA) adhesive. On common substrates such as glass, plastic substrate (PMMA) and tin foil, the tensile shear strength of PolyAspAm(DOPA/OA/EA) adhesive could reach (0.36±0.032) MPa, (0.28±0.021) MPa and (0.29±0.024) MPa, respectively. (3) PolyAspAm(DOPA/OA/EA) adhesive had good bonding stability. After 14 days of application to glass substrate, the tensile shear strength reached the highest value as (0.65±0.029) MPa. (4) The introduction of 5% sodium periodate into PolyAspAm(DOPA/OA/EA) polymer could improve the cohesion of the adhesive, the tensile shear strength on glass substrate increased from (0.36±0.032) MPa to (0.51 ±0.039) MPa.
【Keywords】bio-adhesive; dopamine; polyaspartamide; biomimetic; hydrophobic
Molecular dynamics study on the bonding of polyurethane sealant to glass interface
Shen Hefei1, Han Xiaohui1, Yin Chengze2, Wang Rui1, Zheng Ziqin2, Liang Jingheng2
(1.CRRC Qingdao Sifang Co., Ltd., Qingdao 266111, Shandong, China; 2. Yantai Branch of China Ordnance Industry No.52 Research Institute Co., Ltd., Yantai 264003, Shandong, China)
【Abstract】In order to study the action mechanism of interface molecules on the interface between polyurethane sealant and glass, a microstructure model of polyurethane sealant/glass interface was established. The molecular dynamics simulation method was used to explain the action mechanism of polyurethane sealant/glass bonding interface at the molecular scale. The influence of water molecules and the main components of primer on the interface between them was studied, and verification was carried out through tensile shear test. The simulation research results showed that the addition of water and primer in the interface could improve the adsorption rate of polyurethane sealant on the glass surface, in which the primer acted as a bridge during the movement of polyurethane molecules towards the SiO2 surface, promoting the faster adsorption of polyurethane molecules on the SiO2 surface. By calculating the interaction energy of three configurations, it was found that the presence of water molecules and primer in the interface significantly enhanced the interfacial bonding energy, making it easier for polyurethane molecules to form an excellent bonding interface with the SiO2 surface. The tensile shear test results showed that two surface treatment processes of high humidity and primer could indeed improve the interfacial bonding between polyurethane sealant and glass substrate in the bonding joint, and the test results were consistent with the simulation conclusions. The water molecules and primer in the interface promoted close interfacial bonding through various types of interactions, such as long range van der Waals force and short range hydrogen bond, chemical bond, improving the bonding performance of polyurethane sealant/glass bonding joint.
【Keywords】polyurethane sealant; interface action mechanism; molecular dynamics simulation
Effect of temperature on the properties of quartz fiber reinforced medium-temperature curing epoxy resin composite material
Lu Haijun1,2, Zhang Dujuan1,2, Li Yafeng1,2
(1.AVIC MTI Composite Technology Center, Beijing 101300, China; 2.AVIC BIAM Key Laboratory of Advanced Composites, Beijing 100095, China)
【Abstract】The effect of temperature on the properties of quartz fiber reinforced medium-temperature curing epoxy resin composite material was studied, and the thermal conductivity, thermal expansion coefficient, mechanical properties and dielectric properties of material were characterized. The research results showed that the resin and fiber composing composite material had obvious differences in thermal conductivity and thermal expansion properties, which were the key factors causing internal stress in the material during heating. Under dry condition, in the range of -50~80 ℃, the strength of composite material decreased with the increase of temperature, the modulus did not change significantly, and the mechanical properties of composite material were stable. The mechanical strength and modulus of material decreased significantly after moisture absorption, and the long-term humid and thermal environment would cause significant damage to the resin, fiber and the interface of composite material. After constant temperature at different temperatures, the dielectric constant and loss of AC319 resin and QW280/AC319 composite material increased with temperature, and the change range of dielectric loss was higher than that of dielectric constant, the mobility of polar groups in the material (dipole orientation ability) was the key factor to determine the dielectric constant and loss of resin and composite material. The dielectric constant of resin and composite material showed opposite changes in the process of temperature tracking, the dielectric constant of resin increased first, then decreased and finally stabilized, while the dielectric constant of composite material decreased first, then increased and finally stabilized, mainly due to the interface layer of composite material.
【Keywords】temperature; composite material; mechanical property; dielectric property
Development and Application
Test method and evaluation requirements for underfill voids of ball grid array (BGA) device
Zhang Sheng, Zhang Chenhui, Jin Xing, Liu Zhidan
(Xi'an Research Institute of Navigation Technology, Xi′an 710068, Shaanxi, China)
【Abstract】Based on the reliability application of satellite-borne products for thermal insulation adhesive, the study of test method and evaluation for underfill voids of ball grid array (BGA) device was carried out. Using the daisy-chain network structure test piece, the source process of the voids and main influencing factors of each process were identified through the verification of thermal insulation adhesive filling process. The impact mechanism and consequences of voids on the end machine module were elaborated, and three types of voids were established based on voids position. The calculation of underfill voids rate of large-sized metal packaged BGA device was achieved using an industrial ray computed tomography (CT) imaging system and pixel area statistical method. The research results showed that environmental test had a certain degree of increasing effect on voids rate, but this increase had little effect on the electrical performance of the daisy-chain test piece. It was verified that the daisy-chain test piece had the ability to withstand thermal cycle, sinusoidal vibration, random vibration and thermal vacuum environmental stress, and the void filling rate of thermal insulation adhesive could meet the test requirements of daisy-chain device. The reliability evaluation criteria and examples of the criterion for void filling rate of BGA device with thermal insulation adhesive were clarified, which provided a guide for the optimization and improvement of the filling process.
【Keywords】thermal insulation adhesive; BGA device; daisy-chain; voids rate; industrial CT; environmental test; evaluation criteria
Preparation and performance study of impact resistance UV-curing sealant
Wang Yaoshuang, Lu Xinhang, Wang Shiwei, Xie Shouhua
（Guangdong Provincial Key Laboratory of Electroacoustic Electronic Technology R&D and Application, GuoGuang Electric Company Limited, Guangzhou 510800, Guangdong, China）
【Abstract】Different UV sealants were prepared by using different acrylate monomers, and the effects of different monomers on the mechanical properties, temperature resistance, impact resistance and water resistance of adhesive were compared. The research results showed that the surface tension of monomer was inversely proportional to the shear force of adhesive on PC/PC, and the temperature resistance of adhesive was directly proportional to the glass transition temperature (Tg) of monomer. Adding a high Tg diluent monomer to the adhesive could significantly improve the temperature resistance of adhesive. The impact resistance of adhesive was affected by two aspects. On the one hand, it was affected by the adhesion between adhesive and substrate. On the other hand, the adhesive needed to have both high yield strength and high elongation at break. The impact strength with 25% content of isobornyl acrylate (IBOA) monomer could be maximized. The more ether bond content in the adhesive monomer, the higher water absorption, and the worse water resistance. The water resistance of adhesive with 25% content of dicyclopentenylacrylate (DCPA) monomer was relatively good.
【Keywords】impact resistance; water resistance; diluent monomer; UV sealant
Study on application performance of expanded polytetrafluoroethylene sealing material
Li Yan1, Dou Peng1, Hui Xin1, Ren Jie 2, Gong Haibo2
(1.AVIC Manufacturing Technology Institute, Beijing 100024, China; 2.AVIC Chengdu Aircraft Design & Research Institute, Chengdu 610091, Sichuan, China)
【Abstract】The mechanical properties, dimensional shrinkage rate, compressive stress relaxation and sealing performance of four kinds of expanded polytetrafluoroethylene material (A-D) were compared and analyzed, the effect of material uniformity on the sealing effect was discussed, and the structure-activity relationship between material uniformity and sealing performance was investigated. The research results showed that the tensile strength, medium resistance stability, high-temperature resistance to compressive stress relaxation and short/long-term sealing effect of sealing material C were all the best, and its basic application performance was the best. The dimensional shrinkage rate, compressive stress relaxation and short-term sealing effect of sealing material A were better than those of sealing material B. However, sealing material A leaked in several repeated sealing tests. The long-term sealing effect of sealing material B was better than that of sealing material A. Material uniformity was an important factor in determining the long-term sealing effect of expanded polytetrafluoroethylene sealing material. When there was no significant difference in mechanical properties, dimensional shrinkage rate, compressive stress relaxation and mechanical performance results, the worse the material uniformity, the worse the multiple repeated sealing performance. Therefore, when selecting expanded polytetrafluoroethylene sealing material in future engineering, based on the basic application performance indicators of material, the uniformity of material from different manufacturers was also a key factor to be considered.
【Keywords】expanded polytetrafluoroethylene; sealing material; sealing effect; application performance; material uniformity
Effects of hot melt pressure sensitive adhesive formulation on peeling strength of self-adhesive polymer waterproof roll material with post-cast concrete
He Dian
(Rubber Department, Sinopec Baling Petrochemical Co., Ltd., Yueyang 414014, Hunan, China)
【Abstract】Using styrene-isoprene-styrene (SIS), tackifying resin and plasticizer as raw materials, SIS hot melt pressure sensitive adhesive was prepared. It was evenly coated on HDPE sheets, and the required self-adhesive polymer waterproof roll material was obtained. The effects of different types of SIS grade, tackifying resin, plasticizer, and their addition amounts on the peeling strength of hot melt type self-adhesive polymer waterproof roll material with post-cast concrete were investigated, the formulation of hot melt pressure sensitive adhesive for self-adhesive polymer waterproof roll material was optimized. The research results showed that the ideal raw materials for preparing hot melt pressure sensitive adhesive for self-adhesive polymer waterproof roll material were SIS-1716, hydrogenated C5 petroleum resin, and polyisobutylene PB-950. The optimal formulation was 30 portions of SIS-1716, 53-55 portions of tackifier resin, and 15-17 portions of plasticizer PB-950 in the total mass of 100 portions. The peeling strength of self-adhesive polymer waterproof roll material prepared under this formula with post-cast concrete could reach over 3.60 N/mm.
【Keywords】hot melt pressure sensitive adhesive; formulation; self-adhesive; polymer waterproof roll material; peeling strength; effect
Special Topics and Review
Research progress in improving the processability of phenylethynyl-terminated polyimide
Liu Caizhao, Zhang Song, Zhang Bin, Sun Mingming, Zhang Xugang, Li Jianhui
(Institute of Petrochemistry Heilongjiang Academy of Sciences, Harbin 150040, Heilongjiang, China)
【Abstract】As a kind of organic polymer material with excellent comprehensive performance, polyimide is widely used in aerospace, precision instruments, automobiles, electronics and other fields. Phenylethynyl-terminated polyimide has the advantages of high temperature resistance, good mechanical properties, excellent flame retardance, and no release of small molecules during curing. However, there are also many defects such as high melting temperature, high melt viscosity and low solubility, which limit their application range. In this paper, the research status of improving the processability of phenylethynyl-terminated polyimide was reviewed, and its future development direction was prospected.
【Keywords】low viscosity; solubility; phenylethynyl group; polyimide; processability