【作者】 陈炜；

【导师】 王新灵； 李肇强；

【作者基本信息】 上海交通大学 ， 化学工程， 2007， 硕士

【摘要】 聚氨酯具有优良的耐磨性能、韧性、及高抗冲性等,不仅是一类用途广泛的工程材料,而且还是涂料中重要的基材。不过,用传统原料和方法制备的聚氨酯基材的耐热性较弱,因而限制了它在涂料中的进一步应用。通过共聚的方式将耐热性基团及刚性基团引入到聚氨酯主链中去,是改善聚氨酯基材耐热性能及机械性能的重要方法。本研究分别从硬段和软段两个方面对聚氨酯进行了改性。首先合成了一种含氟芳族二醚胺,并以此为扩链(交联)剂,制备了聚氨酯改性基材,并对其结构和性能进行了讨论。此外,将有机硅引入聚氨酯分子主链中,从软段的角度对聚氨酯基材进行了改性。具体研究内容如下:1.以含氟二苯醚二胺为扩链交联剂制备聚氨酯改性基材用两步法合成了一种新型含氟芳香族二醚胺BAFP,并用红外光谱、核磁共振、元素分析等方法对其结构进行了分析验证。分别以BAFP和传统的3,3′-二氯-4,4′-二氨基二苯基甲烷(MOCA)为扩链交联剂,采取相同的反应条件,用预聚体法制备了两种聚氨酯基材FPUU和MPUU。热重分析的结果表明,FPUU基材的热分解稳定性高于MPUU,这应该是由于氟原子和较多芳醚环的引入,使得聚氨酯基材分子之间的内聚能变大,所以热分解稳定性较好。由拉伸测试的结果可知FPUU基材的拉伸强度和硬度高于MPUU,但断裂伸长率相差不大。此外由红外光谱和差示扫描量热分析的结果可知,FPUU软硬两相微区的相容性相对较大,硬段微区尺寸较小,数量较多,于是硬段能够更加均匀地分散在软段微区中。而由此也可以推断,FPUU基材的微相混容程度比MPUU高,可能是F原子的引入使得两相间的作用力增大的缘故。2.有机硅改性聚氨酯基材的研究用碳羟基封端的聚二甲基硅氧烷(PDMS)和聚四氢呋喃二醇组成混合聚醚,采取本体聚合的方法,将有机硅链段引入到了聚氨酯主链中。场发射扫描电镜和能量散射X-射线光谱的研究结果表明,PDMS加入量超过10%后,有机硅向表面富集的程度便趋于饱和。此外由热失重分析结果可知,引入少量PDMS后,聚氨酯基材的热分解稳定性得到了提高,而其机械性能并没有受到太大影响。不过与前面的新型扩链剂改性后的基材相比,有机硅改性基材的各项热分解温度均相对偏低。这或许可以说明,从软段进行改性,所得基材热分解稳定性的改善效果不如从硬段进行改性的效果显著。从能量散射X-射线光谱和表面水接触角的研究结果可知,将有机硅引入聚氨酯主链后,有机硅链段具有向表面富集的倾向,只是富集的程度不如其他研究中将其引入聚氨酯侧链后的富集程度高。更多还原

【Abstract】 Polyurethanes (PU) are becoming more and more important as engineering materials, and also, important material in paint & coating industry due to their many excellent properties such as high abrasion resistance, chemical resistance and high flexibility. However, it’s well known that conventional polyurethanes exhibit poor thermal stability, which limits their more application in paint & coating fields .An effective way to improve the thermal and mechanical properties of polyurethane is a chemical modification by introducing heteroaromatic groups into polyurethane backbones. In this work, polyurethanes have been modified in view of hard and soft segment respectively. A novel fluoro-containing diamine has been synthesized and was used as the chain-extender to prepare polyurethane(urea) elastomers. In addition, polyurethane was modified by incorporating polydimethylsiloxane into its soft segments in the last sector. The main contents were listed below:1. Polyurethane-urea material based on fluorine-containing bisphenoxydiamineA novel fluorine-containing bisphenoxydiamine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexa- fluoropropane (BAFP), was synthesized and characterized by means of FTIR, nuclear magnetic resonance (NMR) and EA. The obtained BAFP was used as chain-extender to prepare polyurethane-urea material (FPUU), whose morphology and properties was measured through FTIR, DSC, TGA and tensile measurements. The results showed that FPUU exhibited good mechanical properties and thermal stability than conventional polyurethane-urea (MPUU) based on MOCA. On the other hand, it could be concluded that the miscibility between soft and hard segments of FPUU was higher than that of MPUU perhaps because the introduction of fluorine atoms increased the interaction of two segments.2. Silicone-modified polyurethane-urea material A series of silicone-modified polyurethaneurea material (SPUU) were prepared with different composition ofα,ω-(6-hydroxyethoxypropyl) polydimethylsiloxane (PDMS)/polytetramethylene glycol (PTMG) mixed macrodiol. The results of field emission scanning electronic microscope (FESEM) and energy emission X-ray (EDX) measurements showed that no more than 10% (PDMS/PTMG, wt%) of PDMS could be introduced into PUU backbones. If more than 10%, the extra PDMS would separate out from PUU bulk and become solid matter.SPUU material were characterized by means of FTIR, TGA, DSC, tensile measurements and water contact angle. The results indicated that thermal stability of PUU material has been improved by incorporating a small quantity of silicone into the main chains. However, the typical composition temperatures of SPUU were not as high as that of modified PUUs in previous studies. It maybe indicated that the effect of improving the thermal stability by modifying polyurethane soft segments was not as much as that by modifying hard segments. Furthermore, the mechanical property of SPUU material has been weakened due to the introduction of silicone but the decreasing degree was very little.The results of EDX and water contact angle measurements showed that silicone segments tend to appear in the surface of SPUU films. However, compared to silicone-modified polyurethanes by introducing silicone into the side chains, the enrichment degree of silicone was not so high. It’s probably because the main chains limited the activity of silicone segments.更多还原