【作者】 黄鹤；

【导师】 严灏景； 于伟东； 毛志平；

【作者基本信息】 东华大学 ， 纺织材料与纺织品设计， 2009， 博士

【摘要】 本文对形状记忆聚氨酯和温敏性水凝胶的制备作了尝试,对其结构与件能进行了测试及分析,并在此基础上探讨了透湿性可控的智能复合薄膜的制备及其性能表征。以聚己二酸丁二醇酯（PBAG）、聚己内酯（PCL）和聚乙二醇（PEG）为软段材料,甲苯-2,4-二异氰酸酯（TDI）为硬段,1,4-丁二醇（BDO）为扩链剂,采用溶液聚合法。合成了系列形状记忆聚氨酯。由此,系统讨论了软段分子量、硬度含量对聚氨酯热学性能、结晶结构及透湿性能的影响。随着软段分子量和硬段含量的增加,形状记忆聚氨酯软硬链段的相分离程度增加,从而导致薄膜的透湿性能有所增加。同时,随着软段分子量的增加和硬段含量的降低,聚氨酯的触发温度T_s.m向高温区域移动。选取PBAG基形状记忆聚氨酯系列中两种具有代表性的形状记忆聚氨酯,以不同比例进行了物理混合,进而探讨不同混合比例对混合所得的混合型聚氨酯的相转变温度的影响,以及寻找混合型聚氨酯的相转变温度与其组分中各单一聚氨酯的相转变温度之间的关系。基于相同软段材料但不同分子量和硬段含量所得的聚氨酯混合体,其触发温度的变化与其组分中各单一聚氨酯的含量呈现线性变化关系。这种物理共混方法可以成为控制形状记忆聚氨酯触发温度的一种有效方法。并应用于可呼吸织物及膜的制备上,尤其适用于基于相同合成材料的形状记忆聚氨酯。通过在软段材料中引入亲水性聚合物聚乙二醇（PEG）可以获得在室温温度范围的触发温度,且由于聚乙二醇的加入增加了整个聚氨酯体系的亲水性,因此其透湿量也显著提高。以N,N’-亚甲基双丙烯酰胺（BIS）为扩链剂,过硫酸铵（APS）和四甲基乙二胺（TEMED）分别为引发剂和加速剂,采用自由基聚合法合成聚（N-异丙基丙烯酰胺-丙烯酸钠）[poly（NiPAAm-co-SA）]水凝胶。系统研究了聚（N-异丙基丙烯酰胺-丙烯酸钠）凝胶体系在不同丙烯酸钠含量、交联剂浓度、溶液浓度（共聚单体在水溶液中的百分率）及其不同溶胀介质中的溶胀性能。同时,也研究了在不同pH和温度下,凝胶体系的激发响应性能。研究结果表明丙烯酸钠（SA）含量控制在相对于总单体的10%（mol/mol）之内,才能获得有显著热敏性的聚（N-异丙基丙烯酰胺-丙烯酸钠）水凝胶,即水凝胶溶胀率在最低临界溶液温度区域附近的变化幅度可达到和超过50%。由于亲水性共聚单体丙烯酸钠的引入,极大地提高了水凝胶网络的溶胀性能,其溶胀能力相比与未加入丙烯酸单体的水凝胶。提高了20～40倍。在此基础上,采用相分离技术,制备出了具有快速响应性和强溶胀性能的聚（N-异丙基丙烯酰胺-丙烯酸钠）凝胶体系。最后,采用两种方法制备了智能透湿复合薄膜。方法一,是将干凝胶微颗粒与非离子型形状记忆聚氨酯进行复合涂层后,采用湿法成膜工艺制备成膜,方法二,是将溶胀平衡状态下的水凝胶微颗粒与离子型形状记忆聚氨酯进行复合涂层后,采用干法成膜工艺制备成膜。所得到的智能透湿复合薄膜,其透湿原理在于热敏型（形状记忆）聚氨酯随温度升高,链段热运动加剧,产生暂时的缝隙,即膜的自由体积,而自由体积增加导致透气导湿性能的增加。由于在触发温度区域,自由体积会发生突变,故透湿性能突变。与水凝胶微颗粒混合后,形成智能共混体系,由于凝胶微颗粒物质具有热缩冷胀的性能,在外界水汽（如雨滴或者汗液）的环境中,当温度升高时（高于最低临界溶液温度）,水凝胶的体积相转变性能被激发,聚合物网络急剧脱水,表现为体积快速收缩。这会在聚氨酯薄膜中形成孔道,使得膜的透气导湿性能大大提高。当温度降低时,由于水凝胶颗粒遇湿溶胀,孔道封闭,透气导湿性能下降。对制得的智能复合薄膜进行测试后发现,其透湿性能要超越单一组分的形状记忆聚氨酯薄膜,并可以实现薄膜的“双开关”效应,即由组分中的两种智能材料共同控制。更多还原

【Abstract】 Shape memory polyurcthanes （SMPUs） and temperature-sensitive hydrogels were synthesized and prepared. The structure and properties of these two kinds of smart polymers were tested and analyzed. Then these two kinds of polymers were assembled to prepare smart composite membranes, and the water vapor permeability of the membranes could be controlled by temperature.Segmented shape memory polyurethanes were synthesized by solution synthesis method. Poly（butylenes adipate） glycol （PBAG）, polycaprolactone polyol （PCL） and polyethylene glycol （PEG） were used as soft segment, toluene-2,4-diisocyanate （TDI） as hard segment, and 1,4-butanediol （BDO） as chain extender in order to prepare segmented SMPUs. The influence of soft segment molecular weight and hard segment content on the thermal properties, crystallization structures and water vapor permeability was investigated. The phase separation of soft/hard segment of SMPUs was enhanced when the higher hard segment content and larger molecular weight of soft segment was used, which resulted in larger water vapor permeability of shape memory polyurethane membranes. Meanwhile, the trigger temperature T_s.m （the crystalline melting temperature） shifted to higher temperature region with the increase of molecular weight of soft segment and the decrease of hard segment content. Two representative PBAG-based SMPUs were mixed according to different weight ratios in order to adjust the trigger temperature and water vapor permeability of the obtained mixture. The results showed that the shape recovery temperature of mixed polyurethanes based on the same soft segment with differing molecular weight and hard segment contents, changed linearly as a function of the content of either polyurethane. This occurred within the range of the shape recovery temperature of the two kinds of simplex polyurethanes, providing a practical method to control the shape recovery temperature of shape memory polyurethanes. Hydrophilic polymer PEG was used as soft segment with PCL, which could induce a trigger temperature around 30℃. The water vapor permeability of PCL/PEG based SMPUs was enhanced greatly.Poly（N-isopropylacrylamide-co-sodium acrylate） gels with N,N-methylene bisacrylamide （BIS） as crosslinker, ammonium persulfate （APS） and Tetramethylethylenediamine （TEMED） as initiator and accelerator were prepared by free radical polymerization method. The swelling behavior of Poly（NiPAAm-co-SA） hydrogels was investigated systematically by varying the SA contents, crosslinker concentrations, the pre-gel solution concentrations （ total monomer content in water and also in different swelling solution medium） for obtaining higher swellabilities to study the stimuli-sensitive behavior in the solutions with different pH and temperature. The results indicated that the swelling rate of poly（NiPAAm-co-SA） hydrogel with small content of SA can changed about 50% which proved that the content of SA should be controlled within 10% （mol/mol） in order to obtain the hydrogels with distinctive thermo-sensitivity. The introduction of hydrophilic comonomer SA did greatly enhance the swelling ability of poly（NiPAAm-co-SA） hydrogels, which can improve the swelling rate of poly（NiPAAm-co-SA） hydrogels 20-40 times when compared with pure PNiPPAm hydrogels. Phase separation technique was employed to prepare fast response and strong swelling hydrogels.Finally, two methods were used to prepare smart composite membranes. Membrane A was made using dry process by multi-coating poly（NiPAAm-co-SA） hydrogel dry micro-particles and non-ionic shape memory polyurethane. Membrane B was made using wet process by multi-coating poly（NiPAAm-co-SA） hydrogels swollen micro-particles and ionic shape memory polyurethane. The mechanism of water vapor transmission of the membranes is as follow. In the composite system, the water vapor permeability of shape memory polyurethanes can increase dramatically at the trigger temperature, which is provided by the enhanced micro-brown motions of polyurethane molecules around the soft segment crystalline melting temperature （?）s.m· Meanwhile, the hydrogels micro-particles assembled with polyurethane exhibit a reversible volume transition at a transition temperature or lower critical solution temperature （LCST）, that is. the hydrogel particles could swell and deswell dramatically with the change of temperature. When the composite membranes were heated to the temperature above the LCST with the presence of water, the hydrogel particles dispelled greatly and pores were created around the particles. As a result, the water vapor permeability of composite membranes was enhanced greatly. When the temperature decreases, the hydrogel particles swelled and the pores disappeared. The water vapor permeability of the composite membranes decreases. The results showed that the water vapor permeability of composite membranes is superior to the single component membranes, and the "double on-off" effect of water vapor permeability of the composite membranes can be achieved.更多还原