Scientific Research Report

Development of testing device and test method for puncture resistance of adhesive tape

Chen Weibin^1,2, Shen Yan³

(1. Meixin New Material Co., Ltd., Shenzhen  518053, Guangdong, China; 2. Guangdong Provincial Engineering Technology Research Center for High Performance Special Adhesive Materials, Shenzhen  518053, Guangdong, China; 3. Shanghai Institute of Rubber Products Co., Ltd., Shanghai  201702, China)

【Abstract】A set of test device and test method applicable to the puncture resistance of adhesive tape were developed, and the test research was carried out on adhesive tape with different substrates and thicknesses. The change of puncture force during the puncture test was observed, the influence of puncture rate and roughness of the puncture cone head on the puncture performance was discussed, and the stability and consistency of the test method were analyzed. The research results showed that the puncture load and deformation during the puncture resistance test were linearly related to the puncture time. With the increase of the puncture rate, the puncture force showed a decreasing trend and the fluctuation of test data of puncture force increased. In general test method, the default puncture rate was adopted as 50 mm/min. The increase of roughness of puncture cone head reduced the puncture force, and the effect of the roughness controlled at less than 0.8 μm on the puncture force could be negligible. The reproducibility of test results between different test laboratories was relatively good. In addition, due to the high accuracy and precision of the developed test method, it could be applicable for the determination of puncture resistance of adhesive tape made of different substrates. The equipment and fixtures used in the test method were simple, with low investment cost and convenient use, which could be promoted and applied in adhesive tape manufacturers, and could also be referenced in some adhesive tape product standards in the future.

【Keywords】adhesive tape; puncture; puncture force; testing device; test method

Study on the properties of silicone conductive adhesive

Wang Shuqi¹, Zou Hua¹, Zhang Jiyang², Liu Wei¹

(1.College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing  100029, China; 2.Beijing Beihua Xinxiang Special Material Technology Co., Ltd., Beijing  100029, China)

【Abstract】A single-component addition-type silicone conductive adhesive was prepared by using the combination of two-dimensional flake silver powder and nano one-dimensional spherical silver powder as conductive fillers. Its volume resistivity, micro-morphology, tensile shear strength, curing properties and apparent viscosity were analyzed through electrical test, scanning electron microscopy (SEM), tensile shear test, rheological test, and other methods. The research results showed that the conductive adhesive prepared by using multi-dimensional conductive fillers could solidify well. The increase in the proportion of two-dimensional flake silver powder resulted in a small increase in the elastic modulus of conductive adhesive, which was stable between 10⁶-10⁷ Pa, giving the conductive adhesive basic mechanical strength. As the proportion of two-dimensional flake silver powder increased, the proportion of one-dimensional spherical silver powder decreased, the conductivity of silicone conductive adhesive gradually increased, but the bonding property gradually deteriorated. By adjusting the proportion of silver flakes to silver balls, a balance between the two could be achieved, providing a feasible method for optimizing the performance of silicone conductive adhesive. The apparent viscosity of conductive adhesive increased with the increase of the proportion of two-dimensional flake silver powder. The use of multi-dimensional conductive fillers facilitated the regulation of the viscosity of conductive adhesive. Combined with temperature control, the viscosity of conductive adhesive could be effectively regulated, achieving a wider range of process applications.

【Keywords】silicone conductive adhesive; volume resistivity; tensile shear strength; apparent viscosity

Preparation and characterization of waterborne polyurethane based on quadruple hydrogen bonds

Wu Tong¹, Wang Chuanxi¹, Zheng Ruxin¹, Lin Weirong¹, Cai Anmin¹, Gong Sai², Xiang Shanglin²

(1.China Huaneng Clean Energy Research Institute Co., Ltd., Beijing  102209, China; 2. College of Materials Science and Engineering, Nanjing Tech University, Nanjing  211816, Jiangsu, China)

【Abstract】A quadruple hydrogen bonded waterborne polyurethane (H-WPU) was prepared by using polyether diol, isophorone diisocyanate (IPDI), dimethylol propionic acid (DMPA), 1,4-butanediol (BDO), and 5-(2-hydroxyethyl)-6-methyl-2-aminouracil (HMA) as raw materials. The effect of the ratio of chain extender BDO to HMA on its properties was investigated. The research results showed that the characteristic peak of HMA was found from the infrared curves of H-WPU samples, which indicated that the quadruple hydrogen bond unit was introduced into the main chain of polyurethane. From the particle size analysis, it was found that the particle size distribution of four H-WPU emulsions was around 26 nm, and all four emulsions had good stability and could be stored at room temperature for 6 months. From the analysis of dynamic force performance of the films, it could be seen that the storage modulus of four H-WPU films decreased rapidly during the transition from glass state to rubber state. The higher the content of quadruple hydrogen bonds, the stronger the internal hydrogen bond physical crosslinking network, and the higher the initial storage modulus. From the thermal weight loss of the films, it was found that HMA monomer was easy to decompose, the more amount added, the lower the peak temperature (T_max1) of the first phase, however, the trend of decomposition temperature (T_max3) in the soft segment region was not significant compared to the decomposition temperature (T_max2) in the hard segment region. The tensile performance test showed that the more HMA monomer was added, the better the mechanical properties of the film.

【Keywords】waterborne polyurethane; quadruple hydrogen bonds; chain extender; strength

Preparation and properties of epoxy resin toughened by epoxy-terminated polyurethane

Tan Yanfang, Zhao Haipeng, Zhao Yaqi, Feng Qiao, Shi Xiangyang, Xia Xuelian, Wang Zongtao, Wu Yuting

（Henan University of Urban Construction, Pingdingshan  467041, Henan, China）

【Abstract】Polyurethane prepolymer with isocyanate-terminated groups (NCO-PUE) was synthesized by reacting polyethylene glycol (PEG) and isophorone diisocyanate (IPDI). Then it reacted with glycidyl to prepare epoxy-terminated polyurethane (PU-EP), and then epoxy resin was toughened and modified with epoxy-terminated polyurethane (to form EP/PU materials). The structure of PU-EP was characterized by using Fourier transform infrared spectroscopy (FT-IR), the impact cross-section was analyzed by using scanning electron microscopy (SEM), the thermal properties of EP/PU materials were investigated by using differential scanning calorimetry (DSC) curves, and their mechanical properties were studied. The research results showed that with the increase of PU-EP addition amount, the tensile strength of EP/PU materials decreased, the elongation at break increased, the impact strength gradually increased, and the shear strength first increased and then decreased. When the addition amount was 50 phr, the comprehensive performance of EP/PU materials was the best. In the range of 10-100 phr of PU-EP content, the glass transition temperature of EP/PU materials decreased with the increase of PU-EP content, and the decrease degree was linearly related to the change of PU-EP content. The length of PU-EP molecular chain had a great influence on the properties of EP materials, in which the tensile strength gradually decreased with the growth of PU-EP molecular chain, the elongation at break first increased and then decreased, the bonding shear strength (steel-steel) first increased and then decreased, and the impact strength continued to increase with the increase of molecular chain length.

【Keywords】epoxy-terminated polyurethane; toughening and modification; epoxy resin

 Development and Application  

The influence of mineral admixtures on water immersion performance of ceramic tile adhesive

Fan Duncheng, Zhao Lun, Yan Xingli, Wang Wenping, Wang Hongbin, Zhao Minghui

(Oriental Yuhong Mortar & Powder Technology Group Co., Ltd., Beijing  101300, China)

【Abstract】In order to improve water immersion performance of ceramic tile adhesive, the effects of single and compound addition of two mineral admixtures such as slag powder and metakaolin on the tensile bonding strength, water absorption, wetted area of interlayer of ceramic tile adhesive after water immersion were studied, and the action mechanism of mineral admixtures in ceramic tile adhesive was revealed. The research results showed that when slag powder or metakaolin was added alone, with the increase of mineral admixture content, the tensile bonding strength of ceramic tile adhesive after water immersion gradually increased, and the improvement effect of metakaolin on the tensile bonding strength of ceramic tile adhesive after water immersion was better than that of slag powder. Slag powder and metakaolin added alone and in combination significantly improved the tensile bonding strength of ceramic tile adhesive after water immersion. When slag powder and metakaolin were mixed in the mass ratio of 1:1 (mass fraction of 6%), the bonding strength of ceramic tile adhesive after water immersion reached the maximum value as 1.65 MPa. Single or compound addition of mineral admixtures could reduce the water absorption of ceramic tile adhesive and the wetted area of the bonding layer, slowing down the penetration of water into the interior of ceramic tile adhesive. Among them, compound addition was more conducive to reducing the water absorption of ceramic tile adhesive than single addition, and the impact on the wetted area of the bonding layer depended on the addition amount of metakaolin during the compound addition. Analysis of phase and microstructure revealed that the addition of slag powder and metakaolin hindered the formation and crystallization of flake and plate-like portlandite on the surface of aggregate particles and at the interface between ceramic tile adhesive, forming more C-S-H hydration products and polymer film composite structural layers, making the bonding structure of the transition interface more dense, thereby improving the water immersion performance of ceramic tile adhesive.

    【Keywords】slag powder; metakaolin; ceramic tile adhesive; tensile bonding strength after water immersion; portlandite

Study on the binding behavior of typical rubber asphalt

Lu Yongchun¹, Li Xiaotun¹, Zhang Chuanping², Wang Shifeng²

(1.Gansu HATG Low Carbon Technology Co., Ltd., Lanzhou  730099, Gansu, China; 2.School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai  200240, China)

【Abstract】As a binding agent, rubber asphalt has unique advantages in deformation resistance, impact resistance and energy absorption, which can effectively prevent and control low-temperature cracks and reflective cracks in road. However, the bonding and energy absorption behavior of different rubber asphalt in road is still unclear. In this study, recycled (mature) rubber powder was first prepared, and different rubber asphalt was prepared under certain conditions by adding different contents of rubber powder, recycled rubber powder or SBS. The effects of rubber powder type, structure, content, processing technology and loading mode on the conventional properties, bonding and energy absorption behavior of rubber asphalt were studied. The mechanical properties of static pullout strength, shear strength, dynamic impact toughness and construction workability were compared. The research results showed that rubber powder greatly improved the binding performance of asphalt and effectively improved the problem of road cracking. The conventional performance indicators of recycled rubber powder modified asphalt with the same dosage were more reasonable than those of raw rubber powder modified asphalt. Recycled rubber powder was more suitable for high content of modified asphalt than raw rubber powder, and its static bonding performance, shear resistance, and dynamic impact toughness were better. Recycled rubber powder and SBS composite modified asphalt could further optimize the performance of asphalt. When asphalt was modified by 2.5% addition of SBS and 22% addition of recycled rubber powder, it had good conventional performance, as well as pullout strength, shear strength, and impact toughness, making it more suitable for road construction.

【Keywords】rubber asphalt; pullout strength; shear strength; impact toughness; brittle-ductile transition

Study on antistatic and mechanical properties of epoxy resin matrix for composite anchor bolt molding

She Yongming¹, Feng Xiao², Xiao Jie², Zhang Xufeng^2,3

(1. China Shenhua Energy Co., Ltd. Shendong Coal Branch, Yulin  719300, Shaanxi, China; 2. Shandong AOZO New Materials Co., Ltd., Tengzhou  277500, Shandong, China; 3.School of Materials Science & Engineering, Beijing Institute of Technology, Beijing  100081, China)

【Abstract】By adding antistatic agents (conductive carbon black and conductive carbon fiber) to the resin matrix, an antistatic resin matrix for composite anchor bolt molding was developed, and the resin with excellent antistatic and mechanical properties was prepared. The effect of different amounts of antistatic agents on the surface resistance and mechanical properties of resin casting was studied. The research results showed that when adding carbon black ≥ 1.0 parts, the surface resistance met the requirement for mining anchor bolt (surface resistance ≤ 3×10⁸ Ω), the tensile strength of resin casting body > 57 MPa, and the impact strength ≥ 28 kJ/m². When adding carbon fiber ≥ 1.0 parts, the surface resistance met the requirement for mining anchor bolt, the tensile strength of resin casting body > 60 MPa, and the impact strength ≥ 24 kJ/m², indicating high mechanical properties. With the 1.0 part formulation of carbon fiber as the research object, the kinetics of resin curing reaction was studied by using differential scanning calorimetry and extreme value method, and the activation energy of curing reaction was 65.8 kJ/mol. This resin was suitable for pultrusion processing and could be applied to the preparation of mining anchor bolt, and the prepared anchor bolt could achieve long-term antistatic properties.

【Keywords】epoxy resin; antistatic; surface resistance; activation energy

Synthesis and application of blocked isocyanate curing agent

Zhang Yuli, Xia Ying, Yang Boxiang, Zhang Li, Liu Zhiwei, Liu Lingzhi, Wang Shuwei

(School of Textile and Material Engineering, Dalian Polytechnic University, Dalian  116034, Liaoning, China)

【Abstract】The blocked triphenylmethane triisocyanate (B-TTI) was prepared by reacting with triphenylmethane triisocyanate (TTI) using methyl ethyl ketoxime (MEKO) as blocking agent. The degree of reaction between MEKO and TTI at different temperatures and different time was explored. The research results showed that at 50 ℃, the reaction rate between MEKO and TTI was relatively fast. After the blocking was completed, the content of free isocyanates in the system decreased to below 0.05%. When the reaction time was 4 hours or more, the storage performance of the product was good. It was confirmed that the unblocking temperature was around 120 ℃, self-polymerization reaction would occur after unblocking, and the products after unblocking could undergo rapid curing reaction with TTI. The prepared B-TTI was added as the curing agent to TTI, when m(B-TTI):m(TTI)=2:10, the bonding effect was good, and the bonding strength could reach 4.76 MPa.

【Keywords】triphenylmethane triisocyanate; methyl ethyl ketoxime; blocked; curing agent

 Special Topics and Review 

Research progress and application of polymer-based hydrogels

Zhang Jinyu¹, Qu Dezhi², Wang Shuyu¹, Bai Yongping³

(1.College of Biological and Chemical Engineering, Guangxi University of Science and Technology, Liuzhou    545006, Guangxi, China; 2.Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Liuzhou    545006, Guangxi, China; 3.School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin    150001, Heilongjiang, China)

【Abstract】As a kind of polymer material, polymer-based hydrogels possess properties such as biocompatibility, chemical stability, and adjustability, and can be widely used in medicine, environment, and energy fields. In this paper, four kinds of common polymer-based hydrogels, namely polyacrylic acid hydrogel, polyvinyl alcohol hydrogel, polyoxyethylene hydrogel, and polyacrylamide hydrogel were mainly involved. Through literature review and experimental data analysis, the preparation methods, performance parameters and application scope of these four types of hydrogels were summarized. Among them, polyacrylic acid hydrogel was the most commonly used one, with the advantages of good permeability and biodegradability, which was widely used in medical and health fields. Polyvinyl alcohol hydrogel was mainly used for water treatment in the environmental field, with good adsorption performance and reusability. Polyoxyethylene hydrogel was often used as buffer materials for drug controlled release and artificial joints. Polyacrylamide hydrogel was considered as a new material with wide application prospects. In conclusion, as an important new material, polymer-based hydrogel had a wide range of application prospects in the field of medicine, environment, energy, but also faced many challenges. For the direction and focus of future research, continuous in-depth research and exploration were still needed.

【Keywords】polymer-based hydrogel; preparation method; adsorption; sensor; biomedical; tissue engineering

Research and progress of wood friction welding technology

Zhang Jian, Fu Wentao, Zhu Hai

(College of Mechanical and Electrical Engineering, Northeast Forestry University, Harbin  150040, Heilongjiang, China)

【Abstract】In the context of the “Dual Carbon” strategy, wood, as a naturally carbon-negative, green and low-carbon material, is considered as one of the best alternatives to replace high carbon emitting materials such as plastic and steel. Wood welding process does not emit toxic substances and is efficient in processing, making it an environmentally friendly technology, therefore, it is of great significance under the “Dual Carbon” strategy. In this paper, the development and current application status of wood friction welding were briefly introduced, the influencing factors and optimization methods of welding effect were summarized, the welding mechanism was analyzed, and the development trend of wood friction welding was prospected.

【Keywords】wood friction welding; welding effect; welding mechanism; process parameter