【作者】 王小荣；

【导师】 沈一丁；

【作者基本信息】 陕西科技大学 ， 应用化学， 2014， 博士

【摘要】 聚氨酯（PU）材料是一类含有氨基甲酸酯键，脲键等的产品形态多样的多功能合成树脂，氨基甲酸酯键间易形成氢键，氢键作用使PU分子链形成致密聚合物网络，使聚氨酯涂膜具有优异的耐磨性、柔韧性、耐低温及耐化学介质性。本论文针对水性聚氨酯的研究现状，开展了不饱和有机硅单体和丙烯酸酯单体改性聚氨酯乳液的合成工作，系统的研究了制得的硅烷偶联剂和丙烯酸酯单体改性聚氨酯乳液的乳液性能和胶膜性能，且合成的改性聚氨酯乳液可以作为水性漆树脂乳液，制备性能优良的水性清漆，并分别应用于纸张，墙面和木材表面。本论文主要包括以下三个方面的工作：（1）以异佛尔酮二异氰酸酯（IPDI）、聚四氢呋喃二醇（PTMG）、γ-（甲基丙烯酰氧基）丙基三甲氧基硅烷（MEMO）为基本原料，采用偶氮引发剂引发MEMO与聚氨酯预聚体反应，制得了系列不饱和有机硅单体改性的聚氨酯乳液，并外加交联剂进一步提高了胶膜的性能。采用衰减全反射傅里叶变换红外光谱（ATR-FTIR）对产物的结构进行了表征，同时采用动态激光光散射（DLS）、多功能力学实验机及热重分析（TGA）考察了MEMO含量对乳液粒径、胶膜耐水性、力学性能及热性能的影响，同时通过X-光电子能谱（XPS）对胶膜表面的元素进行了分析，以及对胶膜的结晶性及接触角进行了测试。结果表明，ATR-FTIR分析证实了MEMO成功的反应到了聚氨酯分子链上；随着MEMO含量的增加，乳胶粒的粒径从121.4nm降至91.4nm。在w（MEMO）=5.67%，w（COOH）=1.5%，w（AZ）=2%时，胶膜的耐水性最低为14.84%，胶膜的最大拉伸强度为17.334MPa，断裂伸长率为232.56%，且经不饱和有机硅单体改性后聚氨酯的热稳定性提高。XPS分析证实有机硅氧烷已经成功反应到聚氨酯分子链上，胶膜表面Si元素的实际含量比理论计算值略高，表明有机硅组分主要聚集于聚合物膜表面。XRD及接触角测试表明胶膜的结晶性及表面能均降低。将合成的MPU乳液应用于纸张表面，纸张耐折次数达到90次和渗透时间增加至65s，扫描电镜显示乳液成膜性能优良。（2）以聚氨酯乳液作为种子乳液，在丙烯酸酯聚合体系中引入甲基丙烯酸缩水甘油酯（GMA）合成了环氧基团改性的聚氨酯/丙烯酸酯（EPUA）复合乳液。通过流变，表面张力，动态光散射（DLS）和透射电镜（TEM）测试表征了相关乳液的性能。流变测试表明，EPUA乳液表现出剪切变稀的特性，利于涂装后涂料的流动和流平。表面张力测试表明聚氨酯乳液具有相关表面活性剂的性能，随着聚氨酯浓度的增加，乳液的表面张力迅速下降。当聚氨酯乳液浓度为0.3%时，体系表面张力最低为47.98mN/m。DLS结果表明随着GMA含量的增加，乳液的粒径及粒度分散系数均越来越大。TEM测试表明乳液有明显的核壳结构。采用衰减全反射傅里叶变换红外光谱（ATR-FTIR）及X-光电子能谱（XPS）对产物的结构及元素进行了表征，同时采用多功能力学实验机及热重分析（TGA）考察了GMA含量对胶膜耐水性、力学性能及热性能的影响。红外分析证实了丙烯酸酯的存在，XPS测试表明胶膜表面富集有聚氨酯组分，通过对XPS测试结果进行去卷积拟合处理证实了胶膜中含有EPUA组分。随着GMA含量从0%增加到3%，吸水率从18%下降到7.8%，吸THF率从30.1%下降到15.3%。在w（GMA）=3%，w（PA）=20%时，体系的拉伸强度增加到5.825MPa，交联度较高。TGA分析表明随着体系中环氧基团与羧基的反应，交联网络结构形成，胶膜的热稳定性提高。原子力显微镜（AFM）分析表明随着GMA含量的增加，胶膜表面结构中的“沟壑”数量明显减少，胶膜表面平整光滑。将此乳液配制成水性清漆，并采用水性漆性能测试表征了此清漆的性能。结果表明，随着GMA含量的提高，所制得水性清漆的铅笔硬度增加，耐冲击性能变小，柔韧性能好，附着力优良，光泽度逐渐增加，耐磨耗性不断变好，耐失光性好，可作为外墙涂料进行应用。（3）以聚氨酯乳液为种子乳液，烯丙氧基羟丙基磺酸钠(AHPS)为功能性单体，甲基丙烯酸甲酯(MMA)，丙烯酸丁酯(BA)，甲基丙烯酸羟乙酯(HEA)为聚合单体，采用原位乳液聚合法，合成了新型聚氨酯丙烯酸酯(PUAS)复合乳液。采用表面张力，动态光散射（DLS）和透射电镜（TEM）测试表征了相关乳液的性能。随着AHPS用量的增加，乳液的稳定性越来越好。表面张力测试表明采用AHPS合成的乳液表面张力(62.5-65.6mN·m-1)比AHPS单体的表面张力大，且更加接近于水的表面张力，说明绝大部分AHPS单体与丙烯酸酯单体参与了聚合反应，只有很小一部分通过物理作用吸附在粒子表面。随着AHPS含量的从1%增加到4%，乳液的转化率从89.70%上升至95.78%，乳液的粒径则从102nm降至83nm。TEM测试结果表明核壳结构紧密的结合在了一起。采用衰减全反射傅里叶变换红外光谱（ATR-FTIR）及X-光电子能谱（XPS）对产物的结构及元素进行了表征，同时采用拉力试验及热重分析（TGA）考察了AHPS含量对胶膜耐水性、力学性能及热性能的影响。红外分析表明AHPS成功聚合到PUAS分子链上。X-光电子能谱分析表明钠元素主要在胶膜表面富集。随着AHPS用量的增加，PUAS胶膜的拉伸强度不断增加，断裂伸长率不断减小。热重测试结果表明PUAS胶膜中可聚合乳化剂AHPS的加入提高了体系的热稳定性。差示扫描量热分析（DSC）和动态力学分析（DMA）表明随着AHPS含量的增加，胶膜的玻璃化转变温度（Tg）逐渐升高，体系的相容性不断变好。原子力显微镜微观形貌分析表明所制得的胶膜表面平整。漆膜测试性能优良，可作为家具用涂料进行应用。本论文围绕水性聚氨酯乳液展开研究，主要针对水性涂料行业对涂料综合性能要求的不断提高的现状，开发综合性能优良的水性聚氨酯涂料。在无皂乳液技术的条件下，分别采用不饱和硅烷偶联剂，甲基丙烯酸缩水甘油酯和烯丙氧基羟丙基磺酸钠等单体在聚氨酯大分子为自乳化剂条件下，对聚氨酯乳液进行改性研究，制得了具有核壳结构的系列改性聚氨酯复合乳液。同时，深入探讨了改性聚氨酯乳液的乳胶粒及胶膜的形成机理。更多还原

【Abstract】 ~Polyurethane (PU) is one of the most versatile materials in the world today,which contains a significant number of urethane groups (-HN-COO-) and ureagroups (-NH-CO-). The molecular chains can be easily to form compact networkdue to the hydrogen bonds between the urethane groups, so the PU films havebetter abrasion resistance, flexibility, low temperature and chemical resistance. Inthis study, a series of silane and acrylic monomers modified PU emulsions andfilms were prepared and their properties were discussed according to the recentstudy of the waterborne PU. The prepared PU emulsion can be used as mainbinder in clear coatings to obtain a better performance of clear coatings, and theycan be used in the surface of paper, wall and wood. The main works in this studyinclude the following parts:(1) A series of γ-Methacryloxypropyl trimethoxy silane modifiedwaterborne polyurethane(MPU) was synthesized by using isophoronediisocyanate(IPDI), polytetrahydrofuran glycol(PTMG), γ-Methacryloxypropyltrimethoxy silane(MEMO) as raw materials and aziridine was also used toimprove the property of the film. The azo initiators were used to initiate theMEMO react with the PU prepolymer. The structure was characterized byATR-FTIR. Dynamic light scattering (DLS), Multi-function mechanical testingmachine and Thermo gravimetric analysis (TGA) were used to evaluate theeffect of MEMO content on emulsion size, the mechanical properties andthermal stability of the MPU films. The X-ray photoelectron spectroscopy (XPS)was used to analysis the element of the film surface. The crystallinity and contactangle were studied. The ATR-FTIR results showed that MEMO was successfullyintroduced into the PU chains. With the increment of the MEMO content, theparticle size decreased gradually. The results also showed that when w(MEMO)=5.67%,w(COOH)=1.5%,w(AZ)=2%, the water absorption was lowto14.84%, the maximum tensile strength was17.334Mpa, the breakingelongation was232.56%. XPS result indicated that the film surface was rich insilane content. The surface energy and the crystallinity of the polyurethane filmwere decreased while the thermal stability was enhanced. The folding strengthcan be reached to90times, while the penetration time to65s. The SEM showsthat the MPU emulsion’s film formation property on the paper surface was good.(2) Polyurethane/polyacrylate (EPUA) composite emulsions weresynthesized based on the presence of preformed polyurethane chains. Glycidylmethacrylate (GMA), an acrylate monomer, was introduced into the system.Rheology measurements, Surface tension measurements, Dynamic lightscattering (DLS) and Transmission electron microscope (TEM) were used tocharacterize the property of the composite emulsions. The EPUA with acrylicmonomers displays non-Newtonian, shear-thinning behavior during shear ratesweep experiment. Surface tension measurements assured the surface activitiesof the polyurethane emulsion. Normally surface tension decreases as thesurfactant concentration increases, and comes to equilibrium above the criticalmicelle concentration (CMC). The surface tension came to equilibrium at47.98mN/m when the mass concentration is0.3%. Dynamic light scattering(DLS) result showed that the average diameters and polydispersity wereincreased with the increment of GMA content. A core-shell structure is observedby TEM. Attenuated total reflection Fourier transform infrared (ATR-FTIR) andX-ray photoelectron spectroscopy (XPS) were used to test the polymer structureand element content. The tensile test and Thermo gravimetric analysis (TGA)were used to analysis the water resistance, mechanical property and thermalstability of the films. ATR-FTIR analysis ascertains the formation of EPUA, andXPS result indicated that the upper surface was rich in PU phase. The peakdeconvolution results of XPS also confirmed the formation of EPUA. With thew(GMA) increases from0%to3%, the water absorption decrease from18%to7.8%, and the THF absorption decrease from30.1%to15.3%. Whenw(GMA)=3%，w(PA)=20%, the tensile strength was up to5.825MPa, and the gelcontent was also in a high level. TGA of the membranes showed that the thermalstability enhanced and the decomposition temperature was much higher than the pure PU membrane, due to the reaction between the carboxyl groups and theepoxide groups. Atomic force microscopy (AFM) observation performed thatwith the increment of GMA content, the quantity of hills and valleys in thesurface structure were decreased and the extremely flat surface was obtained.The waterborne coating was prepared by using the synthesized emulsion, and thetest showed that with the increment of the GMA, the pencil hardness, gloss andabrasion resistance were all increased, the impact resistance was decreased, thelight loss resistance was good, and it can be used in wall coatings.(3) Novel polyurethane/polyacrylate (PUA) composite emulsions weresynthesized by soap-free emulsion polymerization method from methylmethacrylate (MMA), butyl acrylate (BA), and2-Hydroxyethyl acrylate (HEA)in the presence of PU as seeds and a polymerizable emulsifier-Allyloxy hvdroxylpropanesulfonic salt (AHPS). Surface tension measurements, Dynamic lightscattering (DLS) and Transmission electron microscope (TEM) were used tocharacterize the property of the composite emulsions. With the increment of theAHPS content, the stability of the emulsion was good. Compared with thesurface tension of AHPS, the surface tension of all emulsions prepared by AHPSis very high (from62.5to65.6mN·m-1) and closes to that of water, it can be saidthat large part of AHPS is joined polymerization with monomer, only small partanchored on the surface of the emulsion particles. With augment of the AHPS,the conversion ratio increased sharply from89.70%to95.78%, while theaverage particle diameters of the PUAS emulsion particles, decreased from102nm to83nm as the AHPS amount increased from1to4wt%. A core-shellstructure is observed by TEM. Fourier transform infrared (ATR-FTIR) and X-rayphotoelectron spectroscopy (XPS) were used to test the polymer structure andelement content. The tensile test and Thermo gravimetric analysis (TGA) wereused to analysis the water resistance, mechanical property and thermal stabilityof the films. Fourier transform infrared spectroscopy (FT-IR) result shows thatAHPS was introduced into the PUAS chains. X-ray photoelectron spectroscopy(XPS) analysis showed that sodium was preferably enriched on the surface oflatex particles. With the increment of the AHPS content, the tensile strengthincreased, and the breaking elongation decreased. TGA of the films showed thatthe thermal stability enhanced. The DSC and DMA tests show that Tg of the films increased gradually and the compatibility between the components of thePU and PA is increased with augment of AHPS amount in polymer. Atomic forcemicroscopy (AFM) observation performed the extremely flat membrane.In this paper, we are aimed to explore PU coatings with better properties, soas to satisfy the meetings of the coatings. A series of silane, glycidylmethacrylate (GMA) and allyloxy hvdroxyl propanesulfonic salt(AHPS) wereused to modify PU emulsions and films were prepared and their properties werediscussed according to the recent study of the waterborne PU, and the modifiedPU with core-shell structure were successfully obtained. The latex formationprocess and film-forming mechanismwere also discussed.更多还原