环氧富锌底漆防沉降的研究

系统地研究了防沉剂对环氧富锌底漆的性能影响。结果表明不同种类的防沉剂对环氧富锌底漆的分散性、增稠性、流变性、沉降性和贮存稳定性产生不同的影响,而对防腐性几乎不产生影响。     

快干型水性环氧富锌底漆的研制

以水性环氧树脂作为成膜物质,以锌粉为主要防锈颜料,制备出一种耐腐蚀性良好的快干型水性环氧富锌底漆.对影响环氧富锌底漆耐腐蚀性能和干燥性能的一些因素,如水性环氧树脂和填料的选择、锌粉用量以及助溶剂类型及其复配等进行了研究.结果表明,选用水性树脂C,滑石粉质量分数10%、锌粉质量分数50%,助溶剂b和c按2:1的质量比搭配时,所得水性环氧富锌底漆的性价比最佳,表干时间为5 min.     

水性环氧富锌底漆的研究及评价

以水性环氧树脂、固化剂、锌粉、磷铁粉、防沉剂、闪锈剂等原料合成了水性环氧富锌底漆并进行了分析讨论。表明水性环氧富锌底漆具有溶剂型环氧富锌底漆防腐性好、附着力强等基本性能,又兼具水性无机富锌底漆低VOC和安全性的优点。     

腰果酚基环氧树脂的制备及其硅烷化改性

采用从腰果壳油中提炼出来的腰果酚为原料,在乙酸锌的催化下生成腰果酚基酚醛树脂(CN),随后利用CN在苄基三乙基氯化铵(TEBAC)的催化下进一步合成腰果酚基环氧树脂(CNE),最后对CNE进行有机硅改性,制备了有机硅改性环氧树脂(SICNE).研究结果表明:将CNE和SICNE与三乙烯四胺(TETA)固化后,由于反应性...     

Effect of zinc oxide in combating corrosion in zinc-rich primer

During the production of zinc pigments, some zinc may get oxidized and remains as impurity. In the present study, the effect of spherical ZnO on corrosion protection properties was evaluated along with lamellar zinc. ZnO was added in various weight fractions in epoxy primer coating at 60% PVC. The coated panels were evaluated among others for their conductance, packing density and morphology. The corrosion resistance was measured using salt spray test for 3000 h of exposure. Open circuit potential (i.e. corrosion potential) was measured in 3.5 wt.% NaCl salt solution. The best corrosion protection was obtained with 15 wt.% of ZnO.     

提高水性富锌底漆防腐性能的涂装技术

对溶剂型和水性富锌底漆的施工技术指标进行了对比分析,从除锈等级、表面清洁度和粗糙度以及钢结构表面的缺陷处理等方面论述了喷涂水性富锌涂料对钢材表面处理的要求,并对无气喷涂技术应用于水性富锌底漆涂装中需要注意的事项及对环境条件的要求等进行了探讨。     

UV generation of a multifunctional hyperbranched thermal crosslinker to cure epoxy resins

A new hyperbranched polymer (HBP) was obtained via an iterative synthetic procedure that consists of esterification and thiol-ene click reaction. This polymer was used as a latent multifunctional macroinitiator for the dual curing of a commercially available cycloaliphatic epoxy resin and this process was studied by photo-DSC and FTIR. The presence of thioether groups in the HBP structure leads, by photoirradiation, to the formation of sulfonium salts, which are thermal cationic initiating species. The materials obtained were characterized by DMTA, TGA, gel content and FESEM. By means of the last technique domains of HBP as a second phase within the epoxy matrix were observed.     

Synthesis and evaluating corrosion protection effects of emeraldine base PAni/clay nanocomposite as a barrier pigment in zinc-rich ethyl silicate primer

In the present work, polyaniline/clay nanocomposite (PAniCN) was synthesized by chemical oxidative polymerization of aniline monomers in the presence of Closite30B powders. XRD and SEM examinations were used to examine the intercalation and morphologies of PAniCN, respectively. Electrical conductivity test showed that the conductivity of final PAniCN was higher than pristine PAni by one order of magnitude. Synthesized nanocomposite was added to the zinc rich ethyl silicate primer to modify its barrier properties. The corrosion protection performances of modified and unmodified primers were evaluated using open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) in 3.5% sodium chloride solution for a period of 120 days. It was found that the modified primer had higher barrier properties than original primer. After 120 days of immersion, resistance of modified and unmodified primers reaches 5.565 × 10³ Ω cm² and 6.056 × 10² Ω cm² respectively. The OCP of both primers were lower than −800 mV/SCE during the immersion. Besides, the OCP of modified primer was higher than the original primer due to the passivation and barrier effects of PAniCN. Results revealed that the performance of modified primer improved strongly.     

环氧富锌/氯化橡胶涂层体系腐蚀过程的电化学阻抗谱

采用环氧富锌作为底漆、氯化橡胶作为面漆,研究了涂层体系腐蚀过程中电化学阻抗谱(EIS)的变化。结果表明,腐蚀初期环氧富锌/氯化橡胶涂层体系中底漆的厚度比例与涂层的防护性能无关,而在腐蚀中后期,随底漆厚度比例适当增大,涂层自修复能力增强,离子等腐蚀介质在涂层中的传输速度得到显著延缓,涂层吸水率和孔隙率明显降低,涂层防护性能出现短时间升高。当环氧富锌底漆为涂层总厚度的2/3左右时,涂层体系的防护性能最好,而仅有底漆或面漆的体系则不具备良好的防护性能。     

提高环氧富锌涂料耐盐雾性和稳定性

通过对原料进行试验和筛选,制备了耐盐雾性和耐盐水性及储存稳定性较好的富锌涂料。     

Synthesis and architecture study of a reactive polybutadiene polyamine as a toughening agent for epoxy resin

In this study, a novel reactive toughener for the epoxy resin was developed and compared with traditional hydroxyl‐terminated polybutadiene (HTPB). For this purpose, the highly reactive aliphatic amine‐terminated polybutadiene (ATPB) was synthesized at ambient conditions by nucleophilic substitution amination. The characterizations of the product were provided by Fourier transform infrared and ¹H NMR spectroscopy. According to the mechanical test results, incorporation of ATPB into epoxy networks can significantly toughen the epoxy matrix. The addition of 10 phr ATPB increased the critical stress intensity factor (K_IC) and critical strain energy release rate (G_IC) of the epoxy from 0.85 to 2.16 MPa m^1/2 and from 0.38 to 3.02 kJ m^?2, respectively. Furthermore, unlike HTPB, the presence of the ATPB did not deteriorate the tensile strength of the matrix. The toughening and failure mechanisms were discussed based on the epoxy network morphological characteristics. The reduction in cross‐linking density and glass transition temperature of the epoxy system upon modification with liquid rubbers was confirmed by dynamic mechanical analysis. This article opens up the possibility of utilizing reactive flexible diamines with polybutadiene backbone as effective toughening agents for thermoset polymers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44061.     

Curing kinetics of epoxy cured by cardanol-based phenalkamines synthesized from different polyethylenepolyamines by Mannich reaction

Phenalkamines with different structures are expected to affect the curing reaction of epoxy, yet the exact mechanism remains to be elucidated. In this study, four cardanol-based phenalkamines (named PK1, PK2, PK3, and PK4, respectively), synthesized from ethylenediamine, diethylenetriamine, triethylenetetramine, and pentaethylenehexamine, were used as curing agents in diglycidyl ether of bisphenol A (DGEBA) epoxy system. The phenalkamines were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, and time-of-flight secondary ion mass spectrometry. The curing behaviors and kinetics were investigated by non-isothermal differential scanning calorimetry, and the activation energies of the reactions (E _α ) were determined using Kissinger–Akahira–Sunose (KAS) and Starink methods. The results indicate a similar curing mechanism for all four phenalkamines. All E _α values remain almost constant in the range of 0.05 ≤ α ≤ 0.6, and increase dramatically after α > 0.6 due to greater viscosity of the reaction systems. The diffusion of reactive groups plays an increasingly important role in determining the curing kinetics. In addition, DGEBA/PK1 and DGEBA/PK2 have lower initial E _α values than DGEBA/PK3 and DGEBA/PK4, because PK1 and PK2 have lower viscosity than PK3 and PK4. When α is high, DGEBA/PK1 and DGEBA/PK2 have higher E _α values than DGEBA/PK3 and DGEBA/PK4, because more tertiary amine groups can be formed in the reactions between the epoxy and secondary amine groups in the DGEBA/PK3 and DGEBA/PK4 systems, which catalyze the curing reaction and it thus lowers energetic barrier.     

Thermal and dielectric properties of epoxy/DDS/CTBN adhesive modified by cardanol-based benzoxazine

Cardanol-based benzoxazine (Bz-C) was introduced to a ternary resin system to substitute carboxyl-terminated butadiene–acrylonitrile (CTBN) partially and improve the thermal and dielectric properties of the diglycidyl ether of bisphenol-A (epoxy)/4,4′-diaminodiphenylsulfone (DDS)/CTBN adhesive resin system. The effect of Bz-C on the curing behavior of blends was studied, and factors that affect the thermal, mechanical, and dielectric properties were discussed systematically. Results show that reactions between Ep, DDS, and Bz-C decrease the curing temperature of the quaternary blends and increase the cross-linking densities of the network, leading to higher glass-transition temperature and enhanced mechanical properties. The flexibility of the copolymer films was maintained by the introduction of the aliphatic side chain of Bz-C. Substitution of Bz-C for some group of CTBN in the cross-linked network resulted in decreased dielectric constant and dielectric loss in the copolymer films.     

Investigation of allyl‐capped carbosilane dendrimers used as crosslinker for silicone rubber

High‐temperature vulcanized silicone rubber was prepared by using allyl‐capped carbosilane dendrimers, in which the core molecules were Si(CH₂CH?CH₂)₄ and Ph₂Si(CH₂CH?CH₂)₂ as crosslinker and nanoscale reinforcing filler, respectively. Allyl‐capped carbosilane dendrimers improved the mechanical properties of silicone rubber. The optimum tensile strength and tear strength were 9.6 MPa and 31.0 kN/m, respectively, when using SiG_n(allyl)m as the crosslinker and 10.1 MPa and 32.0 kN/m, respectively, when using Ph₂SiG_n(allyl)m as the crosslinker. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1772–1775, 2006     

Copper particles/epoxy resin thermosetting conductive adhesive using polyamide resin as curing agent

Thermosetting conductive adhesive (TCA) comprised of epoxy resin E‐51 as matrix, Cu microparticles and nanoparticles modified by silane coupling KH550 as conductive fillers, polyamide resin with low molecular weight as curing agent, and some other additives. It was reported creatively a new liquid curing agent, which solved successfully some difficult problems during preparation of TCA, such as limit of quantity of conductive fillers. Therefore, application of this liquid curing agent decreased greatly the resistivity of TCA under the condition of keeping enough adhesion strength. Antioxidized and mixed Cu particles were developed as conductive fillers in place of expensive Ag. The results showed that optimum conditions of conductive adhesive composed of 16 wt % of epoxy resin E‐51, 8 wt % polyamide resin, 65 wt % of Cu microparticles and nanoparticles, 1.3 wt % of silane coupling agent, and 9 wt % of other additives with curing time for 4 h at 60°C. The adhesion strength reached 16.7 MPa and the bulk resistivity was lower than 3.7 × 10^?4 Ω cm. The variation of bulk resistivity was less than 15% at high temperature (100°C). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Dodecyl methacrylate as a crosslinker in the preparation of tough polyacrylamide hydrogels

Copolymerization of acrylamide with dodecyl methacrylate (C12) solubilized in aqueous micelles of sodium dodecyl sulfate produces tough hydrogels exhibiting moduli of elasticity around 1 kPa. Swelling and gel fraction measurements show that the hydrophobic associations acting as temporary crosslinks are too strong to be destroyed in water during the expansion of the gel network. An order of magnitude larger value of loss factor tan δ of the hydrogels formed using the hydrophobe C12 as compared to the conventional hydrogels indicates the dynamic nature of their crosslink zones. The hydrogels are more homogeneous than the corresponding gels prepared by a chemical crosslinker, as determined by the static light scattering measurements. Mechanical tests indicate that, in addition to the dodecyl domains, permanent crosslinks are also needed to obtain hydrogels that are mechanically stable up to 250% elongation ratios.     

钢结构用水性环氧防腐底漆的研制

采用水性环氧固化剂乳化固化液体环氧树脂技术路线,制备钢结构用水性双组分环氧防腐底漆。该底漆VOC含量低,气味和毒性小,涂膜附着力强,耐水、耐碱、耐盐雾性能好。其性能可以达到溶剂型环氧底漆水平,成本与溶剂型环氧底漆相当。     

Reuse of cured epoxy as a reinforcement in an epoxy composite

This article discusses the reuse of a thermoset‐based epoxy polymer. In this method, cured epoxy polymer is ground to powder of particle size ranging from 1 to 30 μm. The ground epoxy is then filled in an epoxy polymer to form an epoxy–epoxy composite system using both room and high temperature processing. The amount of filler material was varied from 1 to 10 wt% in the epoxy matrix. Rheology and tensile properties test were then performed. The result shows that the room temperature‐processed epoxy composites (above 5 wt% of powders) resulted in the formation of voids, agglomeration of particles, and reduced degree of cure leading to a decrease in tensile properties. These drawbacks (voids, agglomeration, and low degree of cure) were correspondingly absent in composites processed at high temperature. Results from this work suggest that the thermoset polymer can be reused effectively with minimal changes to the unfilled resin properties. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

The effect of brominated epoxy on epoxy/phenolic reactive blends

Innovative reactive blends containing epoxy and brominated epoxy (BE) incorporated with resole-type phenolic were studied with the aim to elucidate the curing kinetics and the final thermomechanical characteristics of this unique system. Curing kinetics was investigated by means of the activation energy determined using differential scanning calorimetry (DSC ) at various heating rates analyzed by the Arrhenius equation. Both DSC and Fourier transform infrared revealed that bromine elimination at elevated temperatures (above 220 °C) had lowered the activation energy in the case of BE containing phenolic blends. The thermomechanical properties showed that the addition of conventional epoxy to resole decreased its thermal properties and modulus compared to neat resole. Distinctively, BE/resole blends exhibited increased glass-transition temperature, compared to diglycidyl ether of bisphenol A/resole blends in combination with higher elongation and toughness compared to neat resole. It was concluded that BE/epoxy resin/phenolic reactive systems offer high T _g, mechanical properties and toughness and hence are applicable for structural adhesives and for matrices of polymer-fiber composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47172.