【作者】 戴震；

【导师】 许戈文；

【作者基本信息】 安徽大学 ， 高分子化学与物理， 2011， 硕士

【摘要】 聚氨酯(PU)是分子链段中含氨基甲酸酯结构单元的一类高分子聚合物的总称,分子链上存在大量的极性键,分子间易形成氢键,氢键作用使得涂膜具有优异的强度、耐磨、耐水、耐溶剂、耐低温及粘接等方面性能,广泛应用于涂料、胶黏剂、皮革、纺织、造纸及医药等方面。随着环保法规的确立和人们环保意识的增强,环境友好型聚氨酯应运而生。水性聚氨酯(WPU)是以水代替有机溶剂作为分散介质的新型聚氨酯体系,结合了溶剂型聚氨酯的高性能和水性乳液的低VOC含量,是优异的环境友好型材料。水性聚氨酯涂料符合发展涂料工业的“四E原则”(Economy、Efficience、Ecology、Energy),然而水性聚氨酯分子中亲水性基团的存在及树脂本身的缺陷(如耐温性差、硬度低、耐老化性差等),影响了它的使用范围,许多化学工作者致力于对其进行改性,常见的改性方法有丙烯酸改性、环氧树脂改性、有机硅改性、氟改性、植物油改性、纳米改性等。本论文在阅读大量国内外文献的基础上,根据本实验室具体条件,采用一种新的合成方式,制备了环氧树脂E-51改性水性聚氨酯(EPU)材料和非离子型丙烯酸改性水性聚氨酯(PUA)材料。具体工作分为两个部分：1.环氧树脂E-51改性水性聚氨酯的合成及性能本节选用异佛尔酮二异氰酸酯(IPDI)、聚四氢呋喃二醇(PTMG)、二羟甲基丙酸(DMPA)及一缩二乙二醇(DEG)为主要原料,经相转化法合成了阴离子型水性聚氨酯(WPU)自乳化乳液；然后加入过量胺开环的环氧树脂E-51,后扩链30min,得到环氧树脂E-51改性水性聚氨酯(EPU)乳液。并对这种材料进行了力学、耐水性、硬度、粘度、存储稳定性、粒径、结构及热力学等方面的测试,与改性前进行比较,研究了不同环氧树脂E-51添加量对乳液粒径、粘度、存储稳定性及胶膜强度、接触角、吸水率、硬度、耐热性等方面的影响。结果表明：(1)TEM观察及粒径测试表明WPU及EPU乳液粒子呈球状,乳液平均粒径均小于100nm,随着环氧树脂E-51添加量的提高,EPU乳液的平均粒径增大,且乳液粒径分布变宽；(2)乳液粘度随着环氧树脂E-51添加量的提高而增大,当环氧树脂E-51添加量达8%时乳液稳定性较差；(3)红外光谱分析表明,乙二胺成功开环环氧树脂E-51,且EPU中存在环氧树脂E-51特征吸收峰；(4)力学测试表明,随着环氧树脂E-51添加量的提高,胶膜拉伸强度逐渐增大,断裂伸长率逐渐降低；(5)耐水性及接触测试表明,环氧树脂E-51的添加明显降低胶膜吸水率,且接触角随着环氧树脂E-51添加量的提高而增大；(6)TGA及MCC测试表明,环氧树脂E-51的添加提高了胶膜的耐热性,胶膜热释放速率随着环氧树脂E-51添加量的提高而降低,胶膜的阻燃性得到提高。2.丙烯酸改性水性聚氨酯的合成及性能本节选用异佛尔酮二异氰酸酯(IPDI)、聚氧化丙烯二醇(N-210)、聚氧化乙烯二醇(PEG)等为基本原料,合成端异氰酸根的聚氨酯预聚体；然后采用丙烯酸羟乙酯(HEA)将双键引入到聚氨酯主链上,最后经相转化法合成了非离子型双键封端水性聚氨酯(HPU)乳液。然后采用热引发方式,和甲基丙烯酸甲酯(MMA)及丙烯酸丁酯(BA)进行自由基聚合,将丙烯酸单体接到水性聚氨酯主链上,得到非离子型丙烯酸改性水性聚氨酯(PUA)乳液。并对这种材料进行了耐水性、粒径、电镜、结构及热力学等方面的测试,与改性前进行比较,分析了不同丙烯酸含量对乳液粒径、粒子形貌及胶膜吸水率及热力学等方面的影响。结果表明：(1)TEM观察及粒径测试表明HPU乳液粒子呈球状,PUA及PA乳液粒子有明显核壳结构；乳液平均粒径均小于100nm, PA及HPU乳液粒径分布较窄,随着HPU添加量的提高,PUA乳液的平均粒径增大,且乳液粒径分布变宽；(2)乳液粘度随着HPU添加量的增加而提高,胶膜耐水性随着HPU添加量的提高而降低；(3)红外光谱分析表明,采用理论HEA添加量的120%,于70℃反应3h,封端反应进行的比较完全,PUA中含有HPU及PA的特征吸收峰；(4)TGA及DSC测试表明,PUA胶膜的耐温性较HPU有明显提高,且随着丙烯酸单体含量的增加而提高,且胶膜的玻璃化转变温度随着丙烯酸单体含量的增加而提高。更多还原

【Abstract】 Polyurethane (PU) is one class of polymers which contains repeating urethane groups in the structure. The macromolecular chains of PU contain a lot of polar bonds, so it is apt to form the hydrogen bonding between the PU chains which endows PU with the outstanding strength, abrasion resistance, water repellency, solvent resistance, low-temperature resistance and adhesive.With the inevitable trend of "low-carbon & environmental protection", the regulations and consumer demands are forcing polyurethane industries to develop environmentally friendly products, thus waterborne polyurethane (WPU) comes into being. WPU is a novel PU system dispersed into water instead of organic solvents, so it is a kind of environmentally friendly materials which combines the high performance of solvent-type PU with little or no volatile organic compounds (VOCs). Due to the existence of hydrophilic groups and their inherent defects in the structure, the application range of WPUs is limited. Consequently, many researchers have been devoting their work to modifing the WPUs. Usually, WPUs can be modified by acrylate, epoxy, organosilicone, fluorined compounds, vegetable oils and nano-particles.We had prepared the WPU modified by epoxy resins (E-51) and the non-ionic WPU modified by acrylate, respectively, based on the extensive literature research. The detailed research of this dissertation is composed of the following two parts:1. Preparation and properties of the WPU modified by epoxy resins (E-51) The anionic WPU was synthesized by the phase inversion method, using isophorone diisocyanate (IPDI), polytetramethylene glycol (PTMG), dimethyopropionic acid (DMPA) and diethylene glycol (DEG) as the main raw materials. The epoxy resins (E-51) modified by excess amine were added into the above WPU and stirred for the chain extension (30 min). Then the WPU emulsions modified by epoxy resins (E-51) were obtained. Compared with the unmodified WPU, the influence of the epoxy resins (E-51) content on the particle size, the viscosity, and the storage stability of the emulsions was studied. Meanwhile, the effect of the epoxy resins (E-51) content on the strength, the contact angle, the water absorption, the hardness and the thermal resistance of the WPU coatings was also investigated. The results indicated that:(1) It can be observed from TEM that the particles of the WPU and the epoxy modified WPU (EPU) presented a spherical structure. The particle size tests indicated that the average particle size was lower than 100 nm. Moreover, the average particle size of EPU became larger and the distribution of the particle size became broaden, with the increase of the epoxy resins (E-51) content.(2) The viscosity of the epoxy modified WPU emulsions was improved with the increase of the epoxy resins (E-51) content. However, the storage stability of the emulsions was deteriorative when the epoxy content was 8%.(3) The FTIR spectra suggested that the reaction between ethylenediamine and epoxy resins (E-51) was successfully performed and the FTIR spectra of the EPU displayed the characteristic absorption bands of the epoxy resins (E-51).(4) The tensile tests showed that the tensile strength of the EPU coatings was improved gradually while the elongation at break was reduced gradually as the epoxy resins (E-51) content increased.(5) The water absorption tests indicated that the incorporation of epoxy resins can decrease the water absorption of the EPU coatings obviously. Meanwhile, the contact angle of the EPU coatings became larger with the increase of the epoxy resins (E-51) content.(6) The TGA results showed that the addition of epoxy resins can enhance the thermal stability of the EPU coatings and the MCC results showed that the heat release rate of the EPU coatings was lowered with the increase of the epoxy resins (E-51) content, suggesting the improvement of the flame resistance.2. Preparation and properties of the WPU modified by acrylateThe procedure for fabricating the acrylate modified WPU was illustrated as follows:firstly, the NCO-terminated PU prepolymer was synthesized by isophorone diisocyanate (IPDI), polypropylene glycol (PPG, N-210) and polyethylene glycol (PEG); secondly, the 2-hydroxyethyl acrylate (HEA) was added into the NCO-terminated PU prepolymer as the end capping agent and then the non-ionic WPU modified by HEA (HPU) were prepared via phase inversion method; lastly, the methyl methacrylate (MMA) and the butyl acrylate (BA) monomers were incorporated into HPU by the thermally-initiated free radical polymerization. Thus, the non-ionic acrylate modified WPU emulsions (PUA) were obtained and characterized by the water resistance test, the particle size analyzer, the hardness test, the electron microscope, the thermogravimetric analyse (TGA) and the differential scanning calorimetry (DSC). The detailed research results of this part are listed as follows:(1) It can be observed from TEM that the particles in the HPU emulsions presented a spherical structure, while their counterparts in the PUA and PA emulsions displayed a core-shell structure. The particle size tests indicated that the average particle size was lower than 100 nm. Moreover, the average particle size of PUA became larger and the distribution of the particle size became broaden, with the increase of the HPU content.(2) The viscosity of the PUA emulsions was improved with the increase of the HPU content. However, the water resistance and the hardness exhibited the opposite trend.(3) The FTIR spectra indicated that the end capping reactions between PU prepolymer and HEA were performed thoroughly at 70℃for 3 h when the HEA addition was 120% of the theoretical value. The FTIR spectra of the PUA displayed the characteristic absorption bands of the HPU and PA.(4) The TGA results showed that the thermal stability of the PUA coatings was improved compared with the HPU, and inceased gradually with the increase of the acrylate monomer content. The DSC data indicated that the glass transition temperature (Tg) of the PUA coatings was increased with the increase of the acrylate monomer content.更多还原