蓖麻油聚氨酯-丙烯酸酯复合乳液的合成

采用甲基丙烯酸甲酯（MMA）与蓖麻油水性聚氨酯乳液共聚反应制备聚氨酯丙烯酸酯（PUA）复合乳液,研究了蓖麻油水性聚氨酯性能、MMA添加量、引发剂种类和聚合温度对PUA复合乳液及涂膜性能的影响,并应用傅里叶红外光谱（FTIR）测定反应产物的结构.研究发现,用外观半透明或微透明的PU-M分散液制备的PUA乳液及涂膜性能优良.油溶性引发剂（AIBN）比水溶性引发剂（K₂S₂O₈）更适合本体系的乳液聚合.随着MMA含量增大,PUA复合乳液胶粒粒径增大,黏度减小,涂膜光泽度下降,机械性能变好,耐水性增加.合适的MMA含量为体系总固含量的20%～30%.提出了PUA复合乳液胶粒形成及粒径长大机理.     

聚氨酯-丙烯酸酯复合乳液的合成与性能

采用甲基丙烯酸甲酯(MMA)与水性聚氨酯乳液共聚反应制备聚氨酯-丙烯酸酯(PUA)复合乳液,研究了MMA添加量、引发剂种类和聚合温度对PUA复合乳液及涂膜性能的影响,确定了PUA复合乳液合成的工艺参数。用傅立叶红外光谱(FTIR)测定反应产物的结构。研究发现油溶性引发剂比水溶性引发剂更适合PUA体系的乳液聚合。随着MMA添加量的增大,PUA复合乳液胶粒粒径增大,黏度减小,涂膜光泽度下降,机械性能增强,耐水性增加。     

Preparation in presence of urushiol and properties of acrylate latex with interparticle bridges

Acrylate latices were prepared by seeded emulsion polymerization of methyl methacrylate (MMA) and butyl acrylate (BA) in presence of urushiol with multifunctional groups (0–6 wt%). The emulsion polymerization was strongly influenced by the urushiol content. With increasing urushiol content, the conversion rate of the monomers first increased then decreased, the stability of emulsion polymerization gradually declined, the average particle size of the latex increased from 115.9 to 175.3 nm, and a change from mono- to bimodal particle size distribution occurred. Interestingly, transmission electron microscopy (TEM) showed that some particles were connected by linear bridges in presence of urushiol. Based on results of ¹H nuclear magnetic resonance (NMR) analysis, such formation of interparticle bridges is due to participation of urushiol in the emulsion polymerization of the acrylate monomers. The content of urushiol also affected the properties of latex films. With increasing urushiol content from 0 to 3 wt%, the adhesion, pencil hardness, and contact angle were markedly improved from grade 6 to grade 2, from B to 3H, and from 22° to 61°, respectively, due to formation of interparticle bridges. When the content of urushiol exceeded 3 wt%, the adhesion and pencil hardness remained unchanged, but the water contact angle markedly declined because of higher surface roughness of the latex film. Furthermore, addition of urushiol enhanced the thermal stability of the latex films.     

Emulsion and miniemulsion copolymerization of acrylic monomers in the presence of alkyd resin

Emulsion and miniemulsion copolymerizations were carried out with acrylic monomers (methyl methacrylate, butyl acrylate, and acrylic acid) in the presence of an alkyd resin. Poly(methyl methacrylate) was used as a hydrophobe or cosurfactant in the miniemulsion reactions. The results demonstrate that miniemulsion polymerization is the preferred process, probably because of mass transport limitations of the alkyd in the conventional emulsion polymerization reactions. The monomer emulsions prepared for the miniemulsion reactions were much more stable and the polymerizations were free of coagulum. Reaction rates, particle size characteristics, grafting efficiencies, and some film properties were measured. © 1996 John Wiley & Sons, Inc.     

Preparation of paraffin-based phase-change microcapsules and application in geopolymer coating

A type of paraffin phase-change microcapsule for thermal insulation of exterior walls was prepared by in situ polymerization of low-softening-point paraffin (46°C) as core material and acrylic copolymer as shell. The surface morphology, phase-change thermal properties, and thermal stability were characterized by scanning electron microscopy, laser particle size distribution analysis, differential scanning calorimetry, and thermogravimetric analysis, respectively. The results showed that, for polymerization reaction temperature of 75°C and paraffin/acrylic copolymer mass ratio of 1.8, the microcapsules prepared at rotation speed of 1600 r/min with 8% emulsifiers were spherical particles with smooth surface and average particle size of 0.68 μm. The phase-change temperature and latent heat storage capacity of the microcapsules were 47.8°C and 174 J/g, respectively. The paraffin phase-change microcapsules obtained using the optimum synthesis condition were mixed in a metakaolin-based geopolymer coating at different proportions, and the thermal insulation ability of the resulting phase-change thermal energy storage coating characterized.     

Pickering乳液法制备复合壳层微胶囊及其在涂料中的应用

以水包油(O/W)型Pickering乳液为模板,经UV光聚合法制备复合壳层中空微胶囊,探究了乳化剂纳米粒子的加入方式、粒径和光敏低聚物PUA对微胶囊壳层的影响,并将微胶囊加入到树脂涂层中,探究微胶囊作为填料对涂层基本性能的影响。使用傅立叶变换红外光谱、扫描电镜、光学显微镜、热重等仪器对微胶囊结构进行表征,并对涂层性能进行了测试。结果表明:乳化剂SiO₂-E纳米粒子加入到油相中制备得到的中空微球表面镶嵌有SiO₂-E纳米粒子;乳化剂纳米粒子粒径的增加,影响中空微球的形貌但对尺寸无影响;当PUA的质量分数从10%增加到30%时,中空微胶囊表面分布的纳米粒子减少,断裂伸长率从11.1%增加至34.5%,而最大拉伸应力从21.5 MPa降低至12.1 MPa。中空微胶囊加入到涂料中,随中空微胶囊含量的增加,涂层的铅笔硬度提高且附着力良好。     

Preparation of epoxy resin/acrylic composite latexes by miniemulsion polymerization method

Epoxy resin/acrylic composite latexes were prepared by miniemulsion polymerization. Epoxy resins have a functional epoxy group in them and excellent characteristics, such as heat resistance and good adhesion. Acrylic latexes have weather and water resistance. Combining the epoxy resin and the acrylic latex was an attempt to actualize these advantages. The miniemulsion polymerization method was effective in obtaining the composite latex. A less than 500‐nm droplet size for the monomer preemulsion was necessary to obtain the latex in a stable manner. Dimethylaminoethylmethacrylate and methacrylic acid as the reactive functional monomer with an epoxy group were introduced to the latexes. The effect of the polymerization method of these functional groups on the properties of latexes and their films was investigated. The latex prepared by the two‐stage polymerization method had good polymerization stability, storage stability, and solvent resistance. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 128–133, 2001     

Polymeric coatings based on acrylic resin latexes from miniemulsion polymerization using hydrocarbon resins as osmotic agents

Waterborne acrylic resins with a solid content higher than 40 wt % were obtained by miniemulsion polymerization of methyl methacrylate, butyl acrylate, and acrylic acid using a hydrocarbon coumarone–indene resin (HCR) as osmotic agent. HCR is a cheap polymer widely used for coatings and pressure‐sensitive adhesives. The resin leads to a higher hydrophobicity for the acrylic latex film and acts as osmotic agent in miniemulsion polymerization preventing Ostwald ripening, leading to latexes with particle sizes, size distributions, and stability comparable to those obtained using n‐hexadecane as osmotic agent. However, the monomer conversion and molecular weight were lower, indicating the occurrence of a chain‐transfer reaction. Atomic force microscopy analysis demonstrated that a smooth film surface with phase‐separated morphology was formed when using HCR. Faster film hardness development was achieved with HCR comparing with hexadecane. Compared with market standard in a paint formulation, a similar performance was achieved. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40569.     

Investigations on the mechanical properties of hybrid nanocomposite hard coatings on polycarbonate

Hybrid nanocomposite coatings derived from titanium tetraisopropoxide and epoxy or acrylic modified silanes were deposited on polycarbonate (PC) by dip coating employing various withdrawal speeds followed by ultraviolet and thermal curing. The effect of different organic functional groups in the precursors and ageing effect of these sols were systematically studied with respect to thickness, abrasion resistance, pencil scratch test, nanoindentation hardness and transmittance. The gels derived from the freshly prepared and aged sols were structurally characterized by FT-IR and TEM analysis. The viscosities of the sols were monitored with time. The change in viscosity is rapid for sol from epoxy modified silane. The thickness of the coatings increases with increase in viscosity in case of both the silane precursors. The scratch as well as abrasion resistance increases as a function of coating thickness. The pencil scratch hardness improves from 2B for the bare PC to a maximum of 3H for the coating obtained from an aged sol derived from epoxy modified silane. Also, the abrasion resistance of the coatings from same sol was maximum as evidenced by a <6% change in haze after 500 cycles, vis-a-vis 40% for the bare PC. The coatings from a freshly prepared sol of acrylic modified silane and titania showed the maximum nanoindentation hardness of 0.52 GPa, when compared to 0.23 GPa for the bare PC.     

Facile synthesis of a castor oil-based hyperbranched acrylate oligomer and its application in UV-curable coatings

Fabrication and performance of the castor oil (CO)-based hyperbranched acrylate (C20AA) UV-curable coatings are highlighted in this work. Herein, C20AA was obtained through a facile reaction of a castor oil-based hyperbranched polyol (C20) with acrylic acid. FT-IR and ¹H NMR spectra confirmed the synthesis of the target C20AA. Subsequently, the as-prepared C20AA was employed for crosslinking a commercialized linear polyurethane acrylate (PUA) UV-curable oligomer. Specifically, by varying the content of C20AA over the range of 0, 20, 40, and 60 wt%, a series of UV-curable coatings were prepared and coded as C20AA-0, C20AA-20, C20AA-40, and C20AA-60, respectively, which were further cured under UV irradiation. The effect of C20AA loadings on the UV-curing efficiency and final polymer performance were investigated. Consequently, the tensile strength, Shore D hardness, pencil hardness, gel content, water resistance, and glass-transition temperature of the UV-cured coatings were greatly improved upon the addition of C20AA. Impressively, with the incorporation of 40 wt% C20AA, the resultant UV-cured coating exhibited highest double bond conversion, superior chemical resistance, and good flexibility. Additionally, all of the coatings showed outstanding transparency and good surface microstructures.     

丙烯酸树脂改性水性聚氨酯的结构与性能研究

采用丙烯酸树脂对水性聚氨酯进行改性，得到了共混改性（PU／PA）、共聚改性（PUA’）、接枝改性（PUA）3种丙烯酸改性水性聚氨酯聚合物。通过对改性聚氨酯乳液的激光粒度分析，乳胶膜的红外光谱、热分析、透明性、耐化学性及扫描电镜进行分析，结果表明：改性后的水性聚氨酯，各项性能均有不同程度的提高。在机械共混聚合物PU／PA体系中，聚氨酯分子链和丙烯酸树脂分子链间具有一定的相容性及共混性；在共聚反应聚合物PUA’、PUA体系中，聚氨酯分子链和丙烯酸树脂分子链形成核壳结构，且在PUA中，聚氨酯分子链和丙烯酸树脂分子链之间形成的化学键，可以有效的提高二者的相容性及共混程度。     

Studies on Performance of Cured Water-Borne Melamine–Acrylic Emulsion Coatings

In this study, water-borne coating formulations which could be cured quickly were prepared using acrylic emulsion as the major coating constituent and highly reactive melamine resin as curing agent, and further incorporating a variety of additives. Melamine and acrylic types, melamine/acrylic mass ratio in coating formulation, and curing temperature were found to influence the performance of cured coatings. When melamine resin etherified slightly with methanol was used as curing agent, melamine/acrylic mass ratio was 0.45 and the coating formulation was baked at 170°C for 30 s, it was observed that performance of cured coating was the best. FTIR was used to study molecular structural changes of coatings after curing, and to analyze the cure mechanism of the coating. DSC was used to study the range of temperature in which curing occurred. The water-borne coating prepared in this study could be cured quickly when it was applied on decorative paper surface and baked at high temperature. Performance properties of cured coatings were tested according to standard methods, it was observed that dry heat resistance, wet heat resistance, adhesion, pencil hardness, and stain resistance all met standard requirements.     

New high performance two-component wood coatings comprised of a hydroxy functional acrylic emulsion and a water-dispersible polysiocyanate

Statistical methods were used to develop hydroxy functional acrylic emulsions for use with a water-dispersible polyisocyanate crosslinker. The resulting two-component waterborne coating systems were optimized for kitchen cabinet and office furniture applications. Key performance criteria included appearance and aesthetics, pot life, print and mar resistance, and chemical resistance involving both Kitchen Cabinet Manufacturers’ Association (KCMA) and office furniture requirements. Statistical analysis revealed several strong correlations between acrylic emulsion hydroxy level, particle size, composition T_g, polymerization process and wood coating performance. For example, smaller acrylic emulsion particle size was found to yield many performance benefits with few detriments. Coating formulation variables were also found to be significant. Ultimate coating hardness increased with water-dispersible polyisocyanate level, yet early hardness readings correlated negatively with water-dispersible polyisocyanate level. Plasticization and crosslinking effects were thought to be responsible. A higher ethylene glycol monbutyl ether (EB) coalescent level was found to correlate negatively with coating hardness, suggesting a reaction between the EB hydroxyl group and the water-dispersible polyisocyanate, resulting in plasticization of the coating. Coatings and Colorants Div., 100 Bayer Rd., Pittsburgh, PA 15205-9741 Performance Materials Div., 9921 Brecksville Rd., Brecksville, OH 44141-3259.     

Preparation of Raspberry-Like Adsorbed Silica Nanoparticles via Miniemulsion Polymerization Using a Glycerol-Functionalized Silica Sol

A series of polymer/SiO₂ organic-inorganic composite microspheres were successfully prepared through miniemulsion polymerization. A TEM study indicated that the composite microspheres had raspberry-like morphology and silica particles were successfully deposited onto the surfaces of organic polymer microspheres. The average particle size and the silica content of composite microspheres could range from 180 nm to 240 nm and 15 ～ 35 wt%, respectively. The influence of reaction conditions such as the amount of emulsifier, the sonification frequency and sonification time, the amount of silica sol, butyl acrylate (BA) on the particle size, silica content and morphology of composite microspheres have been studied.     

聚氨酯-聚丙烯酸互穿网络聚合物乳液的合成

以甲苯二异氰酸酯、聚醚多元醇、二羟甲基丙酸、1,4 丁二醇、甲基丙烯酸甲酯、甲基丙烯酸丁酯等为原料,采用原位乳液聚合工艺合成聚氨酯聚丙烯酸酯乳液.研究了单体含量对乳液及胶膜性能的影响.实验结果表明:随着乙烯基单体含量的增加,乳液稳定性下降;胶膜的断裂伸长率降低,硬度和耐水性增加.当乙烯基单体的质量分数为35%时,乳液的稳定性大于365 d,胶膜的断裂伸长率为482%,摆杆硬度为0.68,吸水率为18.7%.红外光谱分析表明合成了聚氨酯聚丙烯酸酯.     

共混法制备低摩擦聚氨酯复合涂层

选用自制聚氨酯、不同规格的聚乙烯蜡及有机硅为原料,采用共混的方法制备了聚氨酯复合涂层,通过测定摩擦系数、铅笔硬度、接触角及划痕试验、扫描电镜等表征手段研究了聚乙烯蜡含量及粒径和有机硅含量对涂层性能的影响。结果表明:聚乙烯蜡含量为1%~3%时,涂层的润滑性较好,且粒径越小对降低涂层摩擦系数越有利。有机硅含量为0.6%时,涂层的润滑效果最好。有机硅和聚乙烯蜡可对涂层润滑效果起到协同作用,且对涂层热性能、硬度、附着力等几乎没有影响。     

水性环氧丙烯酸酯乳液涂层成膜性能

采用细乳液聚合法制备了环氧丙烯酸酯复合乳液,考察了固化温度、固化时间及磷酸酯乳化剂含量对环氧丙烯酸酯复合涂膜性能的影响,结果表明环氧丙烯酸酯复合乳胶粒子呈均匀的球形结构,且平均粒径分布在150 nm左右。当固化温度为120℃、固化时间为2 h、磷酸酯乳化剂含量为3%时,涂层的耐腐蚀性较好。研究了复合乳液的成膜过程和防腐蚀机理,通过复合乳液与金属底材形成致密的钝化膜,阻隔水分子和无机离子的浸入,提高了涂层的防腐性能。     

氢化松香/丙烯酸酯复合细乳液的制备及其性能研究

以氢化松香(HR)作为增黏树脂,采用细乳液聚合法制备了HR/丙烯酸酯复合细乳液。探讨了乳化剂、HR等因素对该乳液及其胶膜性能的影响。结果表明:与常规乳液聚合相比,细乳液聚合制得的乳液粒径更小、粒径分布更窄、单体转化率更高、凝聚率更低、Zeta电位更高且体系更稳定;HR能有效改善PSA(压敏胶)的粘接性能,并且当w(HR)=5%时,PSA的初粘力(9#钢球)、180°剥离强度(11.2 N/25 mm)和持粘力(47 min)相对较好。     

聚己内酯三元醇型双固化聚氨酯丙烯酸酯的合成及其固化膜性能研究

以聚己内酯三元醇、异佛尔酮二异氰酸酯和羟基丙烯酸酯为原料,合成了一种新型聚氨酯丙烯酸酯。该树脂含有C C双键和未封闭的—NCO基团,可同时进行光固化和热固化反应。研究了不同双键含量对体系成膜性能的影响。结果表明,随着双键含量的上升,体系光固化后的摆杆硬度变大,耐溶剂性、玻璃化转变温度、铅笔硬度提高,但是柔韧性下降。同时发现,后期的热固化对体系的硬度和热性能有补强的作用,但是会在一定程度上导致涂膜的柔韧性下降。     

Sol-Gel法制备光固化纳米复合涂料的应用性能

运用紫外光固化技术与溶胶-凝胶（Sol-Gel）法制备紫外光固化纳米复合涂料,考察了SiO2含量及有机树脂结构对涂膜性能的影响.结果表明复合涂料中纳米颗粒具有良好的分散性,并在其表面形成良好的界面结合层;纳米SiO2的加入可以改善涂膜的硬度、附着力和抗冲性能.用该方法得到的EA/PUA纳米复合涂料光固化后涂膜具有优良的综合性能.