PREPARATION AND PROPERTIES OF THERMOSETTING ACRYLIC COATINGS USING TITANIUM-OXO-CLUSTER AS A CURING AGENT

Thermosetting acrylic coatings were prepared by using carboxyl acid group-containing acrylic oligomer and curing with titanium-oxo-clusters which were first pre-hydrolyzed from titanium n-butoxide.The curing ability of the titanium-oxo-cluster was examined using a microdielectric analytical(DEA)curing monitor,Fourier transformed infrared spectroscopy(FTIR),and Soxhlet extraction experiments,and the properties of the resulted coatings were investigated with pendulum hardness tester,dynamic mechanical analysis(DMA),thermogravimetric analysis(TGA)and ultraviolet-visible spectrometer.The effect of titania-oxo-cluster in leading acrylic oligomers to form thermosetting acrylic coatings was confirmed.An increasing pendulum hardness and modulus of acrylic coatings with increasing titania content was observed, which resulted from the increment of crosslinking degree rather than of the titania content.The thermosetting acrylic/titania coatings also showed better thermal stability and higher UV-blocking properties than those coatings using organic curing agent.

Preparation of Silica Powder in Epoxy Resin Wear-Resistant Coating

Silicon powders possess good thermal stability and rub resistance and can be used as the filler of high temperature wear-resistant coating;it can possess good wettability and dispersibility in the organic polymer by surface modification of silane coupling agent. Organic silicon has good thermal stability, which can modify the frangibility and thermal stability of epoxy resin. A certain proportion of modified silica powder, curing agent and additives were dispersed to modified epoxy resin can compound wear-resistant coating. The results show that: the modification effect can be the best if the dosage of silane coupling agent is 1.5% of silicon powder. If the methyl triethoxy silane is 50 phr and modified silica powder is 200 phr, then various performances of coating tend to be the best.

Evaluation of the injection and plugging ability of a novel epoxy resin in cement cracks

Sustained casing pressure(SCP)is a crucial issue in the oil and gas production lifecycle.Epoxy resins,exhibiting exceptional compressive strength,ductility,and shear bonding strength,have the potential to form reliable barriers.The injectivity and sealing capacity of the epoxy resin is crucial parameters for the success of shallow remediation operations.This study aimed to develop and assess a novel solid-free resin sealant as an alternative to Portland cement for mitigating fluid leakage.The investigation evaluated the viscosity,compressive strength,and brittleness index of the epoxy resin sealant,as well as its tangential and normal shear strengths in conjunction with casing steel.The flow characteristics and sealing abilities of conventional cement and epoxy resin were comparatively analyzed in cracks.The results showed that the application of a viscosity reducer facilitated control over the curing time of the epoxy resin,ranging from 1.5 to 6 h,and reduced the initial viscosity from 865.53 to 118.71 m Pa,s.The mechanical properties of the epoxy resin initially increased with a rise in curing agent content before experiencing a minor decrease.The epoxy resin containing 30%curing agent exhibited optimal mechanical properties.After a 14-day curing period,the epoxy resin's compressive strength reached81.37 MPa,2.12 times higher than that of cement,whereas the elastic modulus of cement was 2.99 times greater than that of the epoxy resin.The brittleness index of epoxy resin is only 3.42,demonstrating high flexibility and toughness.The tangential and normal shear strengths of the epoxy resin exceeded those of cement by 3.17 and 2.82 times,respectively.In a 0.5 mm-wide crack,the injection pressure of the epoxy resin remained below 0.075 MPa,indicating superior injection and flow capabilities.Conversely,the injection pressure of cement surged dramatically to 2.61 MPa within 5 min.The breakthrough pressure of0.5 PV epoxy resin reached 7.53 MPa,decreasing the crack's permeability to 0.02 D,a mere 9.49%of the permeability observed following cement plugging.Upon sealing a 2 mm-wide crack using epoxy resin,the maximum breakthrough pressure attained 5.47 MPa,3.48 times of cement.These results suggest that epoxy resin sealant can be employed safely and effectively to seal cracks in the cement.

New flame retardant epoxy resins based on cyclophosphazene-derived curing agents

To obtain high-efficiency flame retardancy of epoxy resins,a cyclophosphazene derivative tri-(ohenylenediamino)cyclotriphosphazene(3 ACP)was successfully synthesized and used as a curing agent for the thermosetting of an epoxy resin system.The flame retardant properties,thermal stability,and pyrolysis mechanism of the resultant thermosets were investigated in detail.The experiments indicated that the synthesized thermoset achieved a UL-94 V-0 rate under a vertical burning test as well as a limiting oxygen index(LOI)of 29.2%,which was able to reach V-0 even when a small amount of 3 ACP was incorporated.Scanning electronic microscopic observation demonstrated that the char residue of the thermosets was extremely expanded after the vertical flame test.Thermal analysis showed that the samples had a lower initial decomposition temperature when 3 ACP was introduced into the epoxy resin systems.This indicates that the carbonization ability of the thermosets was significantly improved at elevated temperatures.In addition,the incorporation of 3 ACP can effectively suppress the release of combustible gases during the pyrolysis process,and the decomposition of E-44/DDS-3 ACP curing systems also promotes the formation of polyphosphoramides charred layer in the condensed phase.The investigation on the chemical structures of both the gaseous and condensed phase pyrolysis process confirmed the flame-retardant mechanism of the 3 ACP-cured epoxy resins.Therefore,the nonflammable halogen-free epoxy resin developed in this study has potential applications in electric and electronic fields for environment protection and human health.

Bio-Based Hyperbranched Toughener From Tannic Acid and Its Enhanced Solvent-Free Epoxy Resin with High Performance

It is essential to design economic and efficient tougheners to prepare high-performance epoxy resin;however,this has remained a huge challenge.Herein,an eco-friendly,low-cost,and facile-fabricated bio-based hyperbranched toughener,carboxylic acid-functionalized tannic acid(CATA),was successfully prepared and applicated to the preparation of solvent-free epoxy resins.The mechanical performance,morphology,structural characterization,and thermal characterization of toughened epoxy resin system were studied.The toughened epoxy resin system with only 1.0wt%CATA reached the highest impact strength,111%higher than the neat epoxy resin system.Notably,the tensile strength and elongation at break of toughened epoxy resin systems increased moderately with increasing CATA loading.Nonphase-separated hybrids with significant toughening effect were obtained.Additionally,the thermal stabilities of toughened epoxy resin systems decreased with increasing CATA loading.This study provides an eco-friendly,cost-effective,and facile approach for the preparation of high-performance,solvent-free epoxy resins with potential for practical applications in sealing integrated circuits and electrical devices fields.

Nucleophilic amino acids as a renewable alternative to petrochemically-derived amines in glycerol epoxy resins

The standard epoxy resin curing agents revealed are from unsustainable petroleum-based sources,which produce poisonous exhaust when cured.Amino acids,a bio-based epoxy curing agent with amino and carboxyl groups,are another potential curing agent.Water-soluble epoxy resins cured with lysine(Lys),glutamic acid(Glu),leucine(Leu),and serine(Ser)as amino acids were inves-tigated.The results showed that the water-soluble epoxy resin(glycerol epoxy resins,GER)was cured with Lys and Glu after reacting.Fourier transform infrared(FT-IR)spectroscopic analysis of the GER-Lys showed that the amino and carboxyl groups of Lys primarily reacted with the epoxy groups of GER.The elongation at break of Lys-cured GER(GER-Lys)cured at 70℃ with a molar ratio of 1꞉0.75 was 75.32%.The fact that elongations at break of GER-Lys(79.43%)were higher than those of GER-Glu(17.33%),respectively supports the decrease of crosslinking density by the amino acid-cured GER reaction.The potential of Lys and Glu alternatives for petrochemical amines is demonstrated and provides promising opportunities for industrial application.

水利工程用环氧树脂改性聚氨酯丙烯酸酯性能研究

水利工程金属结构和水工建筑物常遭受腐蚀、高速含沙水流磨蚀破坏,需对其进行便捷有效的防护。利用环氧树脂对聚氨酯丙烯酸酯(PUA)进行改性提高PUA与基体黏结性能,采用紫外光(UV)固化技术制备PUA涂层。研究了环氧树脂改性PUA的化学结构及环氧树脂用量对PUA的力学性能、热稳定性能、耐溶剂性能和抗冲磨性能的影响。结果表明,环氧树脂改性PUA的拉伸强度随着环氧树脂用量增加,呈下降趋势,当加入5%时,PUA拉伸强度为103.0 MPa,材料呈强而脆的特性。环氧树脂加入提升了PUA的拉伸剪切强度,由0.25 MPa增至1.60 MPa。同时,环氧树脂改性PUA具有良好的耐水性能、耐溶剂性能、抗冲磨性能,5%环氧树脂改性PUA抗冲磨强度为800 h/(kg·m^(2))。

厚朴酚环氧树脂涂层的制备及综合防护性能研究

采用联苯结构的生物质原料厚朴酚合成生物基环氧树脂,以柔性聚醚胺固化剂(D230、D400、D2000及T403)进行固化制备生物基环氧抗冲蚀涂层,探究聚醚胺分子量与官能度对厚朴酚环氧树脂力学性能、防腐性能以及抗冲蚀防护性能的影响,阐述厚朴酚环氧涂层抗冲蚀磨损机理。结果表明:D230固化的厚朴酚环氧涂层在3.5%(质量分数)NaCl溶液中浸泡15 d后仍具有较高的阻抗值(1.25×10^(11)Ω·cm^(2));以T403固化可获得高拉伸强度(26.59 MPa)、低摩擦系数(0.373)和磨损率[0.0183 mm^(3)/(N·m)]涂层;D2000固化的厚朴酚环氧涂层在抗冲蚀测试中表现出较低质量损失(244.74 mg)与体积损失(157 mm^(3))。在固/液/气三相流冲蚀作用下,D2000较长的柔性链段,赋予厚朴酚环氧涂层更好的弹性和柔韧性,降低了冲蚀介质的冲击作用,从而表现出优异的抗冲蚀性能。

1,3-二(2′-氨基亚乙基)-2-甲基咪唑溴盐与环氧树脂E-51的固化工艺

通过咪唑环上的季铵化反应,制备一种适用于环氧树脂的双氨基咪唑类离子液体固化剂1,3-二(2′-氨基亚乙基)-2-甲基咪唑溴盐(DAIL)。以环氧树脂E-51作为基体树脂,深入研究DAIL作为固化剂的固化工艺条件和固化物的性能。结果表明,DAIL可作为环氧树脂E-51的中温固化剂使用,二者的最佳质量比为DAIL∶E-51=20∶100,最佳固化温度范围为74~105℃,后固化温度为162℃,固化后的浇注体样条抗拉强度为159 MPa,弹性模量为2281 MPa,断裂伸长率为12.8%,热分解温度为424.4℃。DMA分析表明DAIL/E-51浇注体最大损耗因子tanδ为0.56,玻璃转化温度θg为83℃,对应的贮存模量E为290 MPa,交联密度为30149 mol·m^(-3)。该结果为高力学性能中温环氧树脂固化剂的使用提供了重要实验依据。

改性异佛尔酮二胺固化剂的制备与固化性能研究

环氧树脂是一种应用广泛的热固性树脂,固化剂在环氧树脂体系占很大的比重。以环氧树脂对固化剂异佛尔酮二胺(IPDA)进行改性,通过不同的配比得到不同性能的改性固化剂。再以不同性能的改性固化剂分别与环氧树脂反应,制得不同的固化样品。运用Gelprof 518树脂行为分析仪对固化过程进行评价分析,对固化样品评价分析,改性固化剂的性能相较于未改性固化剂都有所提高,但性能存在不同,改性IPDA比例为m(NPEL-128)∶m(IPDA)∶m(benzyl alcohol)=9∶46∶45时,反应活性最强。此研究揭示了不同比例固化剂对环氧树脂固化的影响,为工业过程中固化剂改性提供了思路。

水性环氧固化剂的研究及应用进展

水性环氧固化剂是水性环氧树脂自乳化和自固化的关键,其组成、结构对水性环氧树脂性能起着决定性作用。综述了固化剂制备技术,分析了酰胺化多胺法、聚酰胺法及环氧-多胺加成法制备技术及其优缺点,探讨了水性环氧固化剂的应用进展,展望了其未来的发展方向。

高光泽阴极电泳涂料的制备及其性能研究

为提高阴极电泳涂层光泽,将环氧树脂与胺反应并中和,合成水溶性阳离子聚合物分散体,再与季铵盐分散树脂混合研磨制得高光泽阴极电泳涂料专用色浆,并研究主体树脂环氧当量、环氧树脂种类、封闭型异氰酸酯固化剂的封闭剂和异氰酸酯种类、涂料颜基比和色浆细度对阴极电泳涂层光泽的影响。结果表明:当主体树脂环氧当量为400~500 g/mol,使用二聚酸改性环氧树脂制备阳离子聚合物分散体,采用甲苯二异氰酸酯和乙二醇丁醚合成封闭型异氰酸酯固化剂,涂料颜基比控制在0.2左右,色浆细度≤15μm,可制得高光泽阴极电泳涂料,涂层具有良好的机械性能、耐盐雾性和一定的耐老化性能。

香兰素基环氧树脂的制备及性能研究

以香兰素(VAN)改性4,4-二氨基二苯甲烷(DDM),经脱水缩合反应,合成香兰素希夫碱固化剂(VDM)。在催化剂2-乙基-4-甲基咪唑(EMI)作用下,采用VDM固化双酚A型环氧树脂(E44)。交联后的环氧树脂(E44-VDM)表现出优异的拉伸强度(60MPa)、拉伸断裂率(8.2%)和玻璃化转变温度(109℃)。在高温下,基于亚胺键的交换反应,E44-VDM表现出再加工性、快速的应力松弛和形变恢复行为,根据阿伦尼乌斯(Arrhenius)定律,计算出亚胺键交换活化能为65.15kJ/mol。将E44-VDM分别浸没在酸碱溶液中,经过72h处理后,并未溶解或溶胀,仍能保持结构完整性,显示出优异的耐酸碱性。尽管经再加工的E44-VDM力学性能不可避免地低于原始试样,但VDM可应用于多种环氧树脂体系中,可为缓解环境污染和资源消耗提供解决方案。

水性环氧树脂灌浆材料的制备及渗透性能研究

以水性环氧树脂E51为原料、二乙烯三胺(DETA)为固化剂,制备出了水性环氧树脂灌浆材料,研究了DETA用量对灌浆材料凝结时间、黏度、力学强度和渗透性能的影响。结果表明,随着固化剂DETA质量分数的增加,水性环氧树脂灌浆材料的初凝时间逐渐降低,黏度持续增大,粘接强度先增大后减小,热稳定性提高,热失重速率减慢,残炭率提高,渗透时间增多。当DETA质量分数为30%时,灌浆材料的初凝时间最短为8.0 h,对应时刻的黏度最大为80334 mPa·s;当DETA质量分数为25%时,灌浆材料的粘接强度和抗压强度达到了最大值,分别为2.94和59.9 MPa,对应的断裂延伸率为13.82%;在800℃时,DETA质量分数为25%的水性环氧树脂灌浆材料的残炭率为9.3%,渗透时间为1709 s,热稳定性和渗透性能较好。综合分析可知,DETA的最佳质量分数为25%。

环氧涂层与基材附着性能评价

环氧树脂作为最常见的热固性树脂之一,因其自身优异的化学特性被广泛应用于建筑防腐领域。作为涂层使用时,环氧树脂防腐性能的优劣与涂层和基材间的附着力息息相关。通过对比不同固化剂种类确定小分子固化剂三乙烯四胺与环氧树脂固化效果较优,当其与环氧树脂以3∶1的质量比混合时,涂层固化最完全,此时涂层与基材的附着力可达到6.54 MPa,为进一步提高涂层附着强度,在涂层中添加质量分数为1%的MOFs钴纳米粒子,此时涂层附着力提高24%,达到8.11 MPa,在此基础上添加一定量功能颜填料,涂层附着力进一步提升至10.28 MPa。

高触变高抗流挂双组分水性环氧涂料的制备

双组分水性环氧涂料具有触变性和抗流挂性不易调节的问题。采用聚氨酯缔合型增稠剂和膨润土复配,并选用乳液型胺固化剂取代常用的水溶性胺固化剂的方式,制备了一款具有高触变、高抗流挂和优异综合性能的双组分水性环氧涂料。研究了增稠剂和流变助剂的种类及用量、胺固化剂的类型对双组分水性环氧涂料的触变性、抗流挂性及其他应用性能的影响规律,结果表明:6870乳液型胺固化剂与299增稠剂和LT膨润土之间存在相互促进作用,当299增稠剂用量为0.5%、LT膨润土用量为0.3%时,搭配6870乳液型胺固化剂可制得触变指数为4.5、抗流挂极限膜厚为475μm、综合性能优异的双组分水性环氧涂料。

公路用胶粘剂制备与工程造价应用研究

为了提升公路建设用高质量高性价比的胶粘剂,研究制备了环氧树脂配比、固化剂和增韧剂对胶粘剂表干时间、拉伸性能、冲击性能、拉剪强度和压剪强度的影响。结果表明,当环氧树脂816与环氧树脂862配比即m(816)∶m(862)为1∶1时,胶粘剂的表干时间较短、拉剪强度和压剪强度最大,破坏形式为内聚破坏;随着PPG-2000增韧剂(PPG)含量增加,当固化剂为6610和D2238时胶粘剂的拉伸强度都表现为先增后减特征,冲击强度都表现为先增而后趋于稳定,当PPG含量为4%时取得拉伸强度最大值。随着PPG含量增加,当固化剂为6610和D2238时胶粘剂的拉剪强度和压剪强度都表现为逐渐减小特征。适宜的PPG含量为4%,m(816)∶m(862)为1∶1,固化剂选择脂肪胺类6610,此时胶粘剂具有良好的综合性能。

风电混塔用环氧拼接胶在低温下的应用性能研究

自制改性胺固化剂B1与环氧A1组份搭配使用,研究不同的胶体温度对风电用环氧拼接胶施工性能及压缩强度的影响,以及不同改性胺固化剂与不同A组份搭配使用时,风电用环氧拼接胶的施工性能及压缩强度。结果表明:当自制改性胺B1作为固化剂与A1复合使用,并维持胶体温度在20、25℃时,风电用环氧拼接胶具有较好的施工性能和压缩强度;因此建议冬季环境温度在-10~-7℃时,将风电用环氧拼接胶A、B组份升温至20℃再混合使用,此时风电用环氧拼接胶的对粘弯曲性能符合T/CECS 10080—2020的要求。当环氧A4组份与自制改性胺固化剂B1复合使用时,室温调节30 min后,风电用环氧拼接胶的7、14 d压缩强度分别为56.5、71.9 MPa;与B3复合使用时,其7、14 d压缩强度分别为61.2、68.2 MPa,14 d强度低于自制改性胺固化剂B1。

固体环氧树脂固化特性研究

固体环氧树脂是一种广泛应用于各个领域的聚合物材料。本研究采用Gelprof518树脂反应行为分析仪研究了固体环氧E20树脂在不同固化剂添加量、不同种类固化剂及其不同固化温度条件下的固化特性,探究固化温度、固化剂添加量及固化剂种类对固化反应速率的影响。结果表明:固化剂类型、温度和时间对固化反应速率和反应程度有显著影响。不同的固化条件下,固化反应的速率和程度存在差异,随着固化温度的升高,固化时间缩短;随着固化剂添加量的增加固化时间也相应的缩短;四氢邻苯二甲酸酐反应活性较邻苯二甲酸酐高,表现为在相同固化剂添加量下反应时间较短。在实际应用中需要根据具体应用需求进行选择。

新型环氧树脂固化剂2-乙基-4-甲基咪唑三嗪的合成研究

合成并优化了环氧树脂固化剂2-乙基-4-甲基咪唑三嗪。第一步以2-乙基-4-甲基咪唑和丙烯腈为原料,经迈克尔加成反应,得到中间体1-氰乙基-2-乙基-4-甲基咪唑;该反应在水作溶剂、60℃保温8小时条件下,产率达到最优95.5%。第二步以双氰胺为原料,经环合反应得到产物;该反应在乙二醇单甲醚作溶剂、氢氧化钠作碱,123℃反应6 h条件下时得率达到86.4%。经优化后的总收率可达82.5%。