【作者】 张波；

【导师】 杨小牛；

【作者基本信息】 中国科学技术大学 ， 高分子化学与物理， 2020， 硕士

【摘要】 聚氨酯凭借其丰富的原料种类和多样的材料成型工艺可以制备具有耐磨、耐疲劳、隔热和良好的生物相容性等优异性能的材料,能满足不同应用场合的需求。随着科学技术和材料需求的快速发展,开发具有更优异性能的聚氨酯材料满足新发展领域对材料的需求具有重要意义。采用小分子脂肪族二胺作为扩链剂制备聚氨酯材料可以构建更多更强的氢键来提高材料的物理机械性能,二胺丰富的分子结构也能赋予聚氨酯材料性能很宽的可调节范围,但是其高反应活性限制了脂肪族二胺在聚氨酯弹性体和泡沫材料制备中的应用。针对以上问题,本论文采用CO2对氨基进行可逆保护,成功制备了小分子脂肪族二胺扩链的聚氨酯-脲弹性体和泡沫材料。具体的研究内容如下:(1)利用CO2和二胺生成羧酸盐的可逆反应,屏蔽二胺的反应活性。羧酸盐在加热的条件下分解释放出二胺和异氰酸酯基反应完成扩链,释放的CO2气体外排后,得到聚氨酯-脲弹性体材料。基于该方法我们以高活性脂肪族二胺为扩链剂,设计合成了四种不同的聚氨酯-脲弹性体材料,同时与对应的二醇作为扩链剂制备的聚氨酯弹性体进行了对照研究,发现聚氨酯-脲弹性体材料中形成了更多更强的氢键,诱导材料发生了更好的微相分离,赋予了材料更高的橡胶态平台模量、更宽的橡胶态平台温度区间和更好的力学性能,有望解决新发展领域对弹性体材料物理机械性能的需求。(2)利用CO2和二胺生成羧酸盐的可逆反应,通过对发泡温度、催化剂以及羧酸盐用量的调控,得到了泡孔均匀、结构稳定、力学性能和耐疲劳性能优异的泡沫材料。在密度相近的条件下,对比了水和羧酸盐两种不同发泡剂制备泡沫材料的工艺和材料性能的差异。结果表明羧酸盐作为发泡剂制备泡沫材料的方法具有更长的凝胶时间和更高的发泡效率,泡沫材料具有更好的力学和抗疲劳性能,为聚氨酯泡沫材料力学性能的提升提供了新的研究思路,有望解决聚氨酯物理发泡剂破坏环境的问题。更多还原

【Abstract】 Diverse processing technology and abundant raw materials give polyurethane materials excellent properties such as wear resistance,fatigue resistance,heat insulation and good biocompatibility to meet the needs of different applications.With the rapid development of science and technology,developing polyurethane materials with excellent properties to fulfill the requirements of newly developed fields is of significant importance.Using low molecular weight aliphatic diamines to synthesize polyurethane materials is a good way to improve their physical and mechanical properties and the diversiform structures of diamines will give polyurethane materials a wide range of adjustable properties.But the reactivity of low molecular weight aliphatic diamines is too high to be used in the synthesis of polyurethane elastomers and foams.In order to solve the problem mentioned above,carbon dioxide was used to protect amine groups reversibly.After being protected,low molecular weight aliphatic diamines were successfully applied to produce polyurethane elastomers and foam.Details of research work are as follows:(1)The reversible reaction between carbon dioxide,diamines and carbamate salt is used to cover diamine’s reactivity.When being transferred into the hot mold in the plate vulcanizer,diamines gradually release and react with prepolymer under the condition of heating to produce polyurethane-urea elastomer materials.Four kinds of polyurethane-urea elastomers were synthesized with the method mentioned above.Four polyurethane elastomers chain-extended with diols were also prepared as control to investigate the influence of diol and diamine chain extenders on the properties of polyurethane elastomers.Results show that more and stronger hydrogen bonds are formed in the polyurethane-urea elastomers which provide a greater driving force for the formation of better microphase separation and give polyurethane-urea elastomers higher modulus,wider temperature range at rubbery platform and better mechanical properties in comparison to their polyurethane counterparts.This method provides a new avenue to develop polyurethane-urea elastomers with excellent properties which could satisfy the demands of newly emerged fields.(2)The reversible reaction between carbon dioxide,diamines and carbamate salt was utilized to produce polyurethane foams,via varying foaming temperature and the amount of catalyst and carbamate salts used foams with uniform and stable cell structures,excellent mechanical properties and good fatigue resistance were obtained.By contrast,the process of using carbamate salt as foaming agents to produce polyurethane has longer gel time and higher foaming efficiency than that of using water as blowing agents,and the resulting materials give better mechanical and anti-fatigue properties.Using carbamate salts as foaming agent to synthesize polyurethane foam gives guidance to improve the mechanical property of foam and is expected to solve the environmental damage caused by physical foaming agent.更多还原