【作者】 周小三；

【导师】 杲云；

【作者基本信息】 华东理工大学 ， 材料科学与工程， 2011， 博士

【摘要】 一方面传统聚氨酯(PU)材料存在耐热性、耐水性不好,表面性能差的缺点,因而限制了它在某些领域的应用,新型改性聚氨酯的开发变得非常重要。另一方面石油资源枯竭,而硅资源丰富为有机硅类材料提供了巨大的发展空间。目前世界硅单体产能巨大,因此硅类材料的深加工以及应用将有着巨大的发展空间,把硅类材料引入聚氨酯变得十分必要与紧迫,因此寻求新的引入方法以及研究引入后材料宏观性能与微观结构之间的关系意义重大。(1)水性聚氨酯(WPU)合成工艺和配方对微观结构和宏观性能的影响及其机硅改性a)水性聚氨酯合成工艺和配方对微观结构和宏观性能在合成工艺方面研究了预聚体合成中二元醇滴加到异氰酸酯(A法)和异氰酸酯滴加到二元醇(B法)两种加料顺序对水性聚氨酯的微观结构和宏观性能的影响。并利用凝胶渗透色谱(GPC)、红外分峰技术及动态力学热分析对该工艺进行研究,分析的结果反映加料顺序影响亲水硬段在PU主链上分布的均匀性,A法产物的亲水硬段分布较为均匀,硬段聚集也较为有序。采用A法可以得到较稳定的乳液,其涂膜的断裂伸长率较高,吸水率较低。在不同硬段含量对WPU微观结构和宏观性能的影响研究中,本文利用了红外光谱(FTIR)、DSC、XRD研究不同硬段含量对WPU的氢键化与微相分离的影响,研究发现随着硬段含量的增大WPU的相分离程度增大。同时利用万能力学试验机对其宏观性能进行了研究。b)有机硅改性水性聚氨酯合成了一系列的有机硅改性WPU,并通过对C=O的分峰对其氢键化程度进行了研究。通过小角激光散射(SAXS、原子力学显微镜(AFM)对改性的WPU的相分离程度、硬段与软段间界面以及软硬段的大小进行了研究。通过万能力学试验机对其宏观性能进行了研究,借助X射线能谱(EDS)对改性的WPU的表面和本体的硅含量进行了测试结果发现有机硅向聚氨酯膜的表面迁移从而使得聚氨酯具有低表面张力。(2)聚氨酯/二氧化硅/量子点的制备及其性能研究本文首次利用两种完全不同的路线制备出两种水性聚氨酯/二氧化硅/量子点(WPU/ SiO2/CdTe; WPU/SiO2/CdSe)并且首次对复合材料的上转化性能进行了研究。a）通过一步法制备水相SiO2/CdTe,然后通过氨基硅烷偶联剂对SiO2/CdTe表面进行修饰得到Amine-SiO2/CdTe, Amine-SiO2/CdTe与聚氨酯预聚体链端的NCO基团进行反应制备出WPU/SiO2/CdTe。该方法易于商业化且十分环保。我们利用FT-IR, DSC,DMA.万能试验机对WPU/SiO2/CdTe进行表征,发现材料的力学性能以及耐热性得到了较大的提高。另一方面,WPU/二氧化硅/碲化镉复合材料在可见光范围和优越的上转换发光性能。量子点／聚合物复合材料的上转换性能目前还没有报道。这项工作可以为上转换材料提供一个新的方法。b）本文利用Deng的方法合成了CdSe,避免了传统合成方法使用的价格昂贵且毒性极强磷系的原料,通过微乳液聚合,用正硅酸乙酯(TEOS)和3-氨丙基三乙氧基硅烷(APTES)同时对CdSe进行包裹,简化了实验步骤降低了QDs表面配体的交换概率,通过荧光与动态光散射(DLS)分析发现,Amine-Si2/CdSe有着优异的存储稳定性。Amine-SiO2/CdSe与聚氨酯预聚体链端的NCO基团进行反应制备出WPU/SiO2/CdSee。我们利用FT-IR, DSC,DMA万能试验机对WPU/二氧化硅/硒化镉进行表征,发现材料的力学性能以及耐热性得到了更大的提高。在WPU/二氧化硅/量子点纳米复合材料的多功能特性的基础上,可以预见,由于聚氨酯赋予了复合材料的加工性能,这些材料在功能性涂料树脂,光电器件,生物材料以及其它领域发挥越来越重要的作用。(3)硅类纳米粒子改性聚氨酯的研究笼型硅氧烷齐聚物(POSS)改性聚氨酯已成为研究热点,然而带有官能团的POSS价格昂贵制约了由其制备的材料的商业化,本文利用最为常见且廉价的硅醇苯基POSS与聚氨酯预聚体反应制备出PU/POSS杂化材料。并利用FT-IR, AFM, TGA, DMA研究了PU/POSS杂化材料的性能,结果发现POSS的加入降低了相分离,提高了PU耐热性和力学性能。为了获取聚氨酯／二氧化硅(PU/SiO2)杂化材料,本文采用在聚氨酯主链中引入硅烷偶联剂,然后在碱性且潮湿的条件下加入正硅酸乙酯(TEOS)与硅烷偶联剂缩合形成二氧化硅从而制备出PU/SiO2杂化材料。通过(TGA, DMA以及万能拉力试验机和接触角详细研究了硅烷偶联剂以及TEOS的用量对PU/SiO2杂化材料性能的影响,结果表明生成的二氧化硅与聚氨酯形成了较强的化学作用,而不是简单的共混,同时随着生成的二氧化硅的增多杂化材料的热学性能和力学性能都有大幅的提高,并且膜的表面能也有明显的降低。更多还原

【Abstract】 The traditional polyurethane material have some disadvantages in some fileds, such as heat resistance, water resistance and the surface properties, so that its appilication have been limited, the development of new modified polyurethane become very important. On the other hand oil resources becoming poor, but resource-rich silicon offer great space for development of silicone material, so deep processing and applications of silicone will have a huge space for development. The introduction of silicone material to polyurethane has become very necessary and urgent, so looking for new methods and sutding the relationship between the microstructure and great significance of the modified material are very important.(1) The synthetic process and the formula of water-born polyurethane (WPU) affect the microstructure and macroscopic properties of WPU; silicone modified WPU. a) Different synthsis method of the WPU prepolymer were studied by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR) dynamic mechanical thermal analysis(DMA). The result shows the mothod of added polyether into isocyanate have excellent micropropertes and marcoproperties. This method products have more uniform distribution of hydrophilic hard segment and the hard segment aggregation is also more orderly. This method used to obtain a more stable emulsion and the film elongation at break higher, low water absorption. A series of waterborn polyurethane(WPU) was prepared with different hard segment content. The relationship of microstructure and macro performance of they were studied by (FTIR), DSC, XRD. The result shows that with increasing hard segment content the degree of phase separation also increased. b) a silicon modified polyurethaneA series of waterborn polyurethane (WPU) modified by silicon was prepared. The copolymer was characterized by FTIR and the fraction of hydrogen bonded carbonyl group was determined through decomposition of C=O stretching. Energy dispersive X-ray analyzer (EDS) was used to investigate the siloxane concentration.on the surface and bulk regions. The morphology of aqueous polyurethane before and after modification was studied by Small-angle X-ray scattering (SAXS) and Atomic force microscopy (AFM), including the interface between soft and hard micro-domain, the size and shape of the dispersive particles, as well as the degree of the phase separation. It was shown that the degree of hydrogen bonding and phase separation of aqueous polyurethane decreased after the introduction of silicon. The migration of silicon to the surface of the film. Therefore, water resistance improved a lot after the introduction of silicon, and the tensile strength and elongation of modified polyurethane decreased while those of EPDMS(PDMS terminated by hydroxyl polyether) appeared little increase at low content and than decreased.(2)A facile synthesis of waterborne polyurethane/SiO2/QDs nanocomposites with excellent mechanical, thermal and optical propertiesThis is the first use of two completely different routes prepared two kinds of polyurethane/SiO2/quantum dots (PU/SiO2/CdTe; PU/SiO2/CdSe) for the first time on the conversion of the composite material properties were studied.Monodispersed waterborne polyurethane WPU/SiiO2/CdTe-QDs nanocomposites were directly synthesized via the reaction between the groups of amine group (-NH2) on the SiO2-hybrided CdTe QDs surface and an isocyanate end group (-NCO) of polymer chains. The SiO2-hybrided CdTe QDs were characterized by Dynamic Light Scattering. This method is easy commercial and environmentally-friendly.The WPU/Si2/CdTe-QDs nanocomposites were characterized by UV-Visible, FT-IR, TGA, DMA and CMT results showed that the nanocomposites have excellent thermal properties. DMA reveals these nanocomposites also have excellent mechanical properties.The Fluorescence Spectroscopy shows the nanocomposites could emit bright and colorful photoluminescence covering the range from the entire visible light to near infrared (NIR) spectre. These nanocomposites have notably up-conversion fluorescence properties. We have found that WPU/Si2/CdTe-QDs nanocomposites have the strong PL in visable range and excellent UPL property. This work could offer a novel approach to fabricate up-conversion materialsWater-soluble amine-SiO2-coated quantum dots (QDs) were encapsulating hydrophobic QDs into amine-SiO2 via microemulsion method. The amine-SiO2-coated QDs were tested by High-resolution transmission electron microscopy (HRTEM), the results show that amine-SiO2-coated QDs are well defined with monodisperse,water-soluble,highly-stable. Fluorescence emission spectra (PL) show fluorescence spectra of CdSe blue shift and Full width at half maximum (FWHM) broaden after encapsulated.The result of PL and dynamic light scattering (DLS) show that the fluorescence of the amine-SiO2-coated QDs have good stability and dimensional stability.The amount of APTES on the amine-SiiO2-coated QDs were estimated by TGA. Monodispersed waterborne polyurethane (WPU/Si2/CdSe-QDs nanocomposites were directly synthesized via the reaction between the groups of amine group (-NH2) on the SiO2-hybrided CdSe QDs surface and an isocyanate end group (-NCO) of polyurethane chains.The applicaton of amine-SiO2-coated QDs in in the polymer material was also studied. The WPU/SiO2/CdSe-QDs were characterized by FT-IR and TGA, results showed that the nanocomposites have excellent thermal properties. The Fluorescence Spectroscopy shows the nanocomposites could emit bright photoluminescence. DMA reveals these WPU/Si2/CdSe-QDs also have excellent mechanical properties.This work could offer a novel approach to fabricate highly fluorescent QD-polymer composites from aqueous QDs without any post-preparative treatment. On the basis of the versatile properties of WPU/Si2/CdTe-QDs nanocomposites, it is envisioned that these materials could be used as functional coating resins, optoelectronic devices and biomaterials. (3)silicon naonoparticels modify polyurethaneIn this work, we have utilized an open-caged POSS structure containing three functional hydroxyl groups to produce a polyurethane with a POSS core in the polymer chain,the mdified plyurethane were characterized by FT-IR, TGA, results showed that the nanocomposites have excellent thermal properties. DMA reveals these nanocomposites also have excellent mechanical properties. The morphology of polyurethane before and after modification was studied by AFM, including the interface between soft and hard micro-domain, the size and shape of the dispersive particles, as well as the degree of the phase separation. It was shown that the degree of hydrogen bonding and phase separation of aqueous polyurethane decreased after the introduction POSS. The migration of POSS to the surface of the film. Therefore, contact angle improved a lot after the introduction of POSS.A new organic/ingorganic(polyurtane/SiO2) hybrid material was prepared by a simple method. In this paper, Silane coupling agent was introducted to polyurethane chain, then Tetraethoxysilane (TEOS) was added to it which can be hydrolysised and condensated by silane coupling agent in alkaline and humid conditions. The polyurethane/SiO2(PU/SiO2) hybrid material were characterized by FT-IR, TGA, DMA and CMT tensile tester. The results revealed that a strong interaction between PU and SiO2 esists in the PU/SiO2 hybrid materials because of which the hybrid materials have excellent mechanical and thermal properties. The surface morphology of nanocomposites was also studied.更多还原