Modification of Nano-α-Al2O3 and Its Influence on the Surface Properties of Waterborne Polyurethane Resin Composite Passivation Films

Silane coupling agent KH560 was used to modify the surface of nano-α-Al2O3 in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al2O3 was determined by nano-particle size analyzer, and the effects of nano-α-Al2O3 content, ethanol-aqueous solution ratio and KH560 dosage on the dispersion and particle size of nano-α-Al2O3 were investigated. The material structure before and after modification was determined by Fourier transform infrared spectroscopy (FTIR). Aqueous polyurethane resin and inorganic components are combined with modified nano-α-Al2O3 dispersion to form chromium-free passivation solution. The solution is coated on the galvanized sheet, the adhesion and surface hardness are tested, the bonding strength of the coating and the surface hardness of the substrate are discussed. The corrosion resistance and surface morphology of the matrix were investigated by electrochemical test, neutral salt spray test and scanning electron microscope test. The chromium-free passivation film formed after the modification of nano-α-Al2O3 increases the surface hardness of galvanized sheet by about 85%. The corrosion resistance of the film is better than that of a single polyurethane film. The results show that the surface hardness and corrosion resistance of polyurethane resin composite passivation film are significantly improved by the introduction of nano-α-Al2O3.

Preparation and Characterization of Two-component Waterborne Polyurethane Comprised of Water-soluble Acrylic Resin and HDI Biuret

A two-component waterborne polyurethane(2K-WPU) was prepared by mixing water-soluble acrylic resin and hexamethylene diisocyanate biuret, and then diluted for phase inversion with water. Compared with water-soluble acrylic resin, the phase inversion of 2K-WPU occurs at lower water content. It is indicated by TEM that 2K-WPU parti-cles show a core-shell structure, in which HDI biuret is encapsulated by hydrophilic acrylic resin. 2K-WPU emulsion with HDI biuret has larger particle size and narrower distribution index, while for 2K-WPU emulsion with HDI iso-cyanurate, the latex not only has large particle size, but also has two-peak distribution. FTIR shows that the reaction be-tween HDI biuret and acrylic resin can complete in 12h. In addition, studies on effect of composition of acrylic resin on performance of 2K-WPU show that narrowing the polar difference between water-soluble acrylic resin and HDI biuret and improving the miscibility of two components are the key to prepare the transparent and high gloss films with high crosslinking density.

PROGRESS IN PHASE INVERSION EMULSIFICATION FOR EPOXY RESIN WATERBORNE DISPERSIONS

In this review, our recent work in phase inversion emulsification （PIE） for polymer （especially epoxy resin） waterborne dispersions is summarized. Based on experimental results about PIE process, the physical model is proposed which can guide the synthesis of the waterborne dispersions such as polymer/nanoparticle composite dispersion. In the presence of a latent curing catalyst, PIE can give a crosslinkable epoxy resin waterborne dispersion. The dispersions can form cured transparent coatings with some unique properties such as UV shielding. They are promising in functional coatings, waterborne resin matrices for composites, and sizing for high performance fibers.

Waterborne Epoxy Resin Modified by AMPS

A stable epoxy emulsion was prepared with epoxy resin （EP） as raw material, 2-acrylamido-2- methyl-l-propanesulfonic acid （AMPS） as modifier and benzoyl peroxide as initiator. By criterion of yield of the copolymer AMPS-EP, water-solubility, change of the acid value and intrinsic viscosity [η] along with reaction time, the copolymerization course was deduced. It is found that during the process, AMPS takes part in both the grafting copolymerization with epoxy principal chain and the ring-opening polyaddition with epoxy group. It is also discovered that the yield of AMPS-EP and water dispersing varies with reaction time. When it reaches 1.5 h, AMPS-EP can obtain good water-solubility; but the water-solubility will go bad gradually if it exceeds 3.5 h.. R spectrum analysis indicates that partial epoxy group partially remains and the others create sulfonic ester.

PREPARATION OF WATERBORNE ULTRAFINE PARTICLES OF EPOXY RESIN BY PHASE INVERSION TECHNIQUE

Waterborne ultrafine particles of epoxy resin were prepared by phase inversion technique. The results of SEM revealed that the particles diameter was in the range of 50 to 100 nm and the effects on amount of water required at phase inversion point were also discussed.

PREPARATION OF BISPHENOL A EPOXY RESIN WATERBORNE DISPERSIONS BY THE PHASE INVERSION EMULSIFICATION TECHNIQUE

The phase inversion emulsification technique (PIET) is an effective physical method for preparing waterborne dispersions of polymer resins. Some results concerning the preparation of bisphenol A epoxy resin waterborne dispersions by PIET in our laboratory were summarized. Electrical properties, rheological behavior and morphological evolution during phase inversion progress were systematically characterized. The effects of the emulsifier concentration and emulsification temperature on phase inversion progress and the structural features of the waterborne particles were studied as well. The deformation and break up of water drops in a shear field were analyzed in terms of micro-theology, while the interaction and coalescence dynamics of water drops were discussed in terms of DLVO theory and Smoluchowski effective collision theory, respectively. Based on the experimental results and theoretical analysis, a physical model of phase inversion progress was suggested, by which the effects of the parameters on phase inversion progress and the structural features of the waterborne particles were interpreted and predicted.

Cure Behaviors and Water Up-take Evaluation of a New Waterborne Epoxy Resin

Cure behaviors and water up-take evaluation of a low cost, ecofriendly and water soluble epoxy resin prepared by reaction between epichlorohydrin and PEG400, PEG600 and PEG1000, respectively, were investigated using non-isothermal differential scanning calorimetry （DSC） and gravimetrical method, respectively. Factors affecting the cure behaviors as well as water up-take of waterborne epoxy resins, such as amount of triethylenetetramine （TETA） and triethylene diamine （TEDA）, PEG molecular weight, curing temperature, were systematically investigated. The prepared water soluble epoxy resins can be cured under room temperature with the shape of the curing curves similar to that expected for an autocatalytic reaction.

Mechanism Analysis of Stiffness Improvement by Waterborne Epoxy Resin Surface Sizing Agent

Low-basis-weight paper lacks normal strength and stiffness. Waterborne epoxy resin could be employed with oxidized starch to improve paper stiffness through surface sizing. In this study,the mechanism of enhancing stiffness by adding waterborne epoxy resin was fully investigated. The results indicated that through surface sizing with epoxy resin,the paper thickness was preserved,whereas the elastic modulus increased significantly and the epoxy resin had positive impact on single fiber strength. A rigid resin layer and interpenetrating polymer network formed on the surface and in the inner layer of the paper,respectively. The formed resin layer and interpenetrating polymer network strongly supported the paper,leading to the improvement of the elastic modulus and stiffness. The stiffness improvement through surface sizing was mainly due to the formation of a fibrous composite layer and penetration of the sizing agent into the inner layers of the paper. The better the combination between fiber and sizing agent,the higher were the elastic modulus and the stiffness of the whole paper.

RHEOLOGICAL BEHAVIOR OF EPOXY RESIN WATERBORNE DISPERSIONS

The waterborne dispersions of epoxy resin were prepared by the phase inversion emulsification technique. Rheological behavior and its relationship with the structural change of the systems were studied. It was shown that the concentrated dispersions were highly viscoelastic and pseudoplastic, which was attributed to the formation of a physical network among the waterborne particles via hydrogen bond. The dilute dispersions were Newtonian fluids. The discrete clusters composed of small waterborne particles were found in diluted dispersions. With increasing solid content, there existed a structural transition via percolation through a cluster-cluster aggregation mode to form the physical network, which was qualitatively evidenced by the TEM morphologies.

MICRO-PHASE SAEPARATION IN EPOXY RESIN WATERBORNE PARTICLES DURING CURING PROCESS

Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples possessed one glass transition temperature （Tg） and two exothermal processes during DSC heating scannings. After being thermally treated above the exothermal peak temperature, they possessed two glass transition temperatures with the disappearance of exothermal peaks, whilst a core/shell structure was formed. This was likely related with the outward diffusion of reactive oligomers to the outer layer of particles.

Compatibility evaluation between waterborne epoxy resin and SBR latex modified asphalt emulsion

Good compatibility between waterborne epoxy resin(WER)modifier and styrene-butadiene rubber(SBR)latex modified asphalt emulsion(SBRE)is an essential premise for good pavement performance of WER and SBR latex compositely modified asphalt emulsion(WSAE).This study aims to explore the compatibility between WER modifier and SBRE.To achieve the goal,several WER modifiers produced by two methods were first selected to modify SBRE,thus the WSAEs were prepared.Next,storage stability and workability of the WSAEs themselves,and high-temperature performance,rheological behavior and temperature sensitivity of their evaporated residues were compared and evaluated via performing a series of experiments,respectively,thus the WER modifier possessing an optimal modification effect was recommended.Results show that the storage stability of WSAEs is sensitive to the amount of WERs.The incorporation of 1%WERs by the mass of SBRE improves the storage stability of SBRE,while WERs that exceed 1%weaken its storage stability.When the WERs reach 3%and 4%,the 5 d storage stability of prepared WSAEs will be beyond the limitation of specification.Incorporating WERs into SBRE negatively affects the workability of SBRE,and the workability of WSAEs is adversely influenced by the WERs content and the storage time.To ensure the construction,the WSAEs with 3%and 4%WERs should not be stored for more than 36 h and 48 h,respectively.The WERs effectively improve the high-temperature performance of SBRE residue,especially the 3%WERs.Besides,the WERs notably enhance the rheological property and thermal stability of SBRE residue.In contrast,the WER modifier produced by chemically modified method has a smaller adverse impact on the storage stability and workability of WSAE,and a larger enhancement on the high-temperature performance,rheological property and thermal stability of SBRE residue,which is thus recommended to modify SBRE.

水性环氧树脂-聚丙烯纤维改性水泥基快速修补砂浆性能研究

为改善机场道面修补砂浆脆性大和粘结性能差等问题,本文利用水性环氧树脂(WER)、聚丙烯(PP)纤维和硫铝酸盐水泥(SAC)制备出一种快速修补砂浆,并对其工作性能、力学性能、阻尼性能和耐硫酸盐腐蚀性能进行研究。结果表明,PP纤维和WER可显著提高快速修补砂浆韧性和粘结性能,使得快速修补砂浆2 h抗压、抗折强度和粘结强度分别达到22.3,5.1和3.7MPa,满足民用机场规范要求,同时可改善快速修补砂浆的阻尼性能和抗硫酸盐侵蚀性能。

水性环氧树脂改性的建筑结构密封胶缓凝性能研究

为研究水性环氧树脂建筑结构密封胶缓凝性能,选用水性环氧树脂、水性环氧树脂固化剂、MS聚合物、硅烷偶联剂、纳米碳酸钙以及不同填料等试剂,以MS聚合物质量为标准设定试剂比例,分别制备A组分与B组分,将2组分依照1∶1质量比混合配比,由此获取不同配比条件下的改性密封胶样本。结果显示,在偶联剂用量达到2%以上时,密封胶样本的适用期符合建筑结构密封胶应用的适用期标准;水性环氧树脂用量为25%,密封胶样本硬度最优;当密封胶样本内不同填料质量比达到3.4∶20∶66∶16时,密封胶样本不会发生流淌现象;不同MS聚合物具有不同特征。

水性丙烯酸树脂对PBAT/淀粉复合材料性能影响

研究了四种水性丙烯酸树脂对聚对苯二甲酸-己二酸丁二酯(PBAT)/淀粉复合材料性能的影响,选择最佳水性丙烯酸树脂进一步研究其用量对复合材料性能的影响。通过万能拉伸测试仪、熔体流动速率仪、接触角测试仪、差式扫描量热仪、热失重分析仪对复合材料力学性能、熔体流动性能、亲水性能、热性能进行了分析;采用红外光谱仪、偏光显微镜对PBAT/淀粉复合材的分子结构与微观组织形貌进行了表征。研究结果表明:玻璃化温度较低的水性丙烯酸树脂对淀粉的改性效果更佳;当水性丙烯酸树脂7168(B7168)用量为25.2g时,复合材料拉伸强度和断裂伸长率有最佳值,较空白样提高10.8%和38.5%;随B7168的增加,复合材料熔体流动速率先减小后趋于平缓,亲水性能增加,对PBAT的结晶和熔融温度影响不明显,对球晶形貌影响不大,但使球晶平均直径略有减小,3000~3600 cm^(-1)的红外响应峰强度有增加的趋势,波峰略向低波数方向移动;热失重显示B7168的加入,使体系热分解起始温度提前,700℃残余量增加。

水性环氧乳液/海泡石复合改性苯丙乳液涂层粘结性能研究

采用物理共混法制备水性环氧乳液/海泡石复合改性苯丙乳液涂层,探讨了苯丙-水性环氧乳液配比,三乙醇胺、填料及乳化沥青掺量对涂层粘结强度的影响,同时考察了复合涂层的抗渗性和耐高低温性。结果表明,当苯丙乳液与水性环氧乳液的有效质量比为1∶2,三乙醇胺、海泡石和乳化沥青掺量分别为2%、3%、5%时,复合涂层粘结强度为3.54MPa,与钢板间具有较好的相容性,且不透水性和耐高低温性优良。

基于响应曲面法的WER-SBR复合改性乳化沥青性能研究

为了定量分析水性环氧树脂(WER)和丁苯橡胶乳液(SBR)对乳化沥青性能的影响,并优化其配合比设计。基于响应曲面法设计了三因素三水平正交试验并以WER掺量、SBR掺量及固化温度为试验变量,以三大指标、车辙因子以及S/m值作为响应指标,利用Box-Behnken模型进行WER-SBR复合改性乳化沥青试验设计,并对试验结果进行回归分析。结果表明:WER能显著提高乳化沥青的高温性能,而低温性能的改善主要得益于SBR的低温柔韧性,固化温度对各响应指标的影响均呈现先增加后减小的变化趋势;当WER掺量为16%,SBR掺量为4%,固化温度为70℃时综合性能最优,其三大指标均满足规范值,高低温性能均优于单一改性乳化沥青和基质乳化沥青;实际试验值与预测值误差均不超过1%,表明改性剂掺量及固化条件可以利用响应曲面法进行设计、优化、预测,且结果具有一定的可靠度。

植酸改性水性环氧乳液的制备及其应用研究

以环氧树脂E20、聚乙二醇二缩水甘油醚和聚醚胺为原料制备了水性环氧树脂乳化剂,进一步添加植酸,并通过相反转法获得了均匀分散的水性环氧乳液。通过耐盐水腐蚀试验、交流阻抗能谱和极化曲线考察了植酸添加量对乳液性能的影响,筛选性能最优的乳液。基于水性环氧乳液制备水性环氧涂料,并涂覆于测试钢板上获得清漆和灰漆涂层。对涂层进行铅笔硬度、附着力、耐盐水和电化学测试,结果表明:植酸添加量为1.0 g时制备的乳液性能最优,涂层具有优异的防腐蚀性能;清漆涂层的铅笔硬度为HB,附着力为0级,耐盐水时间达480 h;灰漆铅笔硬度为H,附着力为0级,耐盐水时间高于720 h。

水性无机耐高温防腐涂料的研制

以硅烷KH560、甲基三甲氧基硅烷偶联剂、气相二氧化硅和氢氧化钾为主要原料合成水性无机耐高温树脂,为提高涂料的耐热性,选择铜铬黑、磷酸锌、碳酸镁作为主要颜填料,并选用抗开裂粉料、消泡剂、分散剂等提高涂层外观及涂料的施工性能等。结果表明,该涂料有机挥发物低于100mg/L,涂层能在200℃固化成膜,700℃煅烧2h仍具有良好的防腐性能,且附着力好、耐盐雾性能良好。

纤维增韧水性环氧乳化沥青混合料性能研究

为提升水性环氧乳化沥青混合料的韧性,采用3种不同类型的纤维材料,分别为木质素纤维、聚酯纤维和玄武岩纤维,并探究它们在不同掺量(0.2%,0.4%,0.6%)下对水性环氧乳化沥青混合料路用性能的影响规律,对9组纤维改性后的水性环氧乳化沥青混合料进行了马歇尔稳定度试验、单轴压缩蠕变试验、低温劈裂试验、冻融劈裂试验、动态模量试验和间接拉伸疲劳试验,得到了马歇尔稳定度、蠕变变形量、破坏拉伸应变、冻融劈裂抗拉强度比、动态模量和疲劳寿命等评价指标结果,并与空白样的各项性能进行了对比分析。研究结果显示:纤维的掺加增加了混合料的最佳乳液含量,并显著增强了集料间的黏结力,从而有效改善了混合料的抗水损害能力。同时,纤维改性对水性环氧乳化沥青混合料的韧性和扩张力也有显著影响,经过纤维增韧处理的混合料在低温劈裂试验中的破坏拉伸应变最大可提升33.6%。基于纤维在提升水性环氧乳化沥青混合料性能方面的效果进行排序,玄武岩纤维表现最佳,其次为聚酯纤维,而木质素纤维排在第3。综合考虑路用性能和经济性,木质素纤维、聚酯纤维、玄武岩纤维的推荐掺量分别为0.2%,0.2%,0.4%。值得注意的是,高掺量的纤维可能导致其在混合料中分散性差,形成力学薄弱点,因此在选择纤维掺量时应对其予以谨慎考虑。

热塑性复合材料玻璃纤维环氧成膜剂的制备与性能研究

本文采用化学改性法,以环氧氯丙烷、共聚物P105、环氧树脂E-51和双酚A为原料,制备了一种水性环氧树脂乳液作为玻璃纤维成膜剂,研究了原料摩尔比、E-P105用量和乳化温度对乳液粒径和稳定性的影响。结果表明,当P105、ECH、NaOH摩尔比为1∶1.5∶1.2,环氧树脂与双酚A摩尔比为2.25∶1,E-P105质量份数为环氧树脂和双酚A质量的20%,乳化温度为60℃时,乳液粒径为0.387μm,粒径分布均匀,具有良好的稳定性,经上浆处理后的玻璃纤维复合材料力学性能优异。