二元溶剂两步法制备聚氨酯膜及纤维的性能研究

发布时间：2018-05-02 19:17

本文选题：聚氨酯膜 + 甲苯　；参考：《武汉纺织大学》2017年硕士论文

【摘要】：聚氨酯是由硬段相和软段相组成的高分子材料,其性能主要取决于软硬段的相结构和微相分离程度。聚氨酯中的硬段是由强极性和刚性的氨基甲酸酯等基团组成,由于其内聚能大,分子间形成的氢键使其聚集在一起形成硬段区;而极性较弱的聚醚段或聚酯段等聚集在一起形成软段区。蜘蛛丝由于其高强高韧的性能引起了广泛的研究,研究者认为蜘蛛丝高强高韧的原因是由于蜘蛛丝中含有完全结晶区、准结晶区以及无定形区三相结构。有人对聚氨酯在不同溶剂下的溶胀状态做了研究,发现溶剂可以减小聚氨酯分子链中硬段区的氢键作用,会造成聚氨酯的强力降低,断裂伸长率增加。通过对比聚氨酯的分子结构和蜘蛛丝的分子结构,本文采用甲苯作为溶剂溶胀聚氨酯,使得聚氨酯中小部分的硬段介于硬段和软段之间,来模拟蜘蛛丝的三相结构。通过上述方式制得的聚氨酯材料与纯DMF为溶剂湿法成型的聚氨酯材料相比,在强力和伸长方面有显著提高,与纯DMF为溶剂干法成型的聚氨酯材料相比,断裂伸长率和断裂功有显著提高。本文采用甲苯与DMF二元溶剂制备聚氨酯材料,主要开展以下三个方面的工作:第一,通过改变二元溶剂中甲苯与DMF的比例,制备出了聚氨酯干法膜。通过扫描电镜观察不同比例溶剂体系制备出的膜的横截面,发现不同比例溶剂体系所制备的聚氨酯膜与DMF为单一溶剂制备出的聚氨酯干法膜的截面均较为致密,无明显差异,且其力学性能相似。第二,采用二元溶剂两步法制备出了聚氨酯膜,通过扫描电镜、红外光谱、热学性能、热力学性能和力学性能测试对不同比例二元溶剂两步法制备的聚氨酯膜的结构和性能进行了表征。通过膜截面的扫描电镜图可知,随着二元溶剂中甲苯比例的增加,聚氨酯膜的表面更加光滑,横截面更加致密;通过傅里叶红外光谱分析可知,在3300cm-1附近的吸收峰向高波段略有偏移且峰变宽,表明随着二元溶剂中甲苯比例的增加,聚氨酯膜的硬段中的氢键减弱;通过DSC和DMA的测试可知,当二元溶剂中甲苯比例为30%时,聚氨酯材料的玻璃化转变温度最低,表明聚氨酯材料的软链段变得更软了;通过力学性能测试可知,当二元溶剂中甲苯比例为30%时,聚氨酯膜的拉伸应力,拉伸应变和断裂功最大,分别为27.72MPa,2034.18%和10.25J,是单一溶剂DMF湿法制备的聚氨酯膜拉伸应力的6.45倍,拉伸应变的3.18倍,断裂功的8.47倍。通过与二元溶剂制备的干法膜对比可知,二元溶剂两步法制备的聚氨酯膜约为干法膜拉伸应变的2.11倍,断裂功的2倍,而拉伸应力有所降低,是干法拉伸应力的78.26%。第三,通过采用二元溶剂两步法制备出了聚氨酯纤维,通过扫描电镜和力学性能测试对不同比例二元溶剂两步法制备的聚氨酯纤维的结构和性能进行了表征。通过膜截面的扫描电镜图可知,随着二元溶剂中甲苯比例的增加,聚氨酯纤维的横截面更加致密;通过力学性能测试可知,随着二元溶剂中甲苯比例的增加,纤维的力学性能具有较大的提高,且当甲苯比例为30%时,聚氨酯纤维的断裂伸长率达到最大。
[Abstract]:Polyurethane is a polymer material composed of hard segment phase and soft segment. Its properties mainly depend on the phase structure and phase separation degree of the soft and hard segments. The hard segments in the polyurethane are composed of strong and rigid carbamate groups. Because of their large cohesive energy and hydrogen bonds formed by intermolecular hydrogen bonds, the hard segments are formed together to form a hard segment. The weak polyether segments or polyester segments gather together to form a soft segment together. Spider silk has been widely studied because of its high strength and toughness. The reasons for the high strength and toughness of the spider silk are due to the three phase structure of the spider silk, which contains the complete crystalline area, the quasi crystalline area and the amorphous region. The swelling state has been studied. It is found that the solvent can reduce the hydrogen bond in the hard segment of the polyurethane chain, resulting in the strength reduction of the polyurethane and the increase of the elongation at break. By comparing the molecular structure of the polyurethane and the molecular structure of the spider silk, the toluene is used as solvent to expand the polyurethane to make the hard segments of the medium and small parts of the polyurethane. Between the hard segment and the soft segment, the three phase structure of the spider silk is simulated. The polyurethane material obtained by the above method is significantly improved in strength and elongation compared with the pure DMF for the solvent wet forming of the polyurethane. Compared with the pure DMF as the solvent based polyurethane, the breaking elongation and fracture work are significantly improved. This paper uses two elements solvent of toluene and DMF to prepare the polyurethane material. The main work is to carry out the following three aspects: first, by changing the proportion of toluene and DMF in the two element solvent, the dry membrane of the polyurethane is prepared. The cross section of the film prepared by different proportion solvent system is observed by scanning electron microscope, and the different proportion of solvent system is found. The cross-sections of the polyurethane film prepared by the polyurethane film and DMF for the single solvent are relatively compact, and the mechanical properties are similar. Second, the polyurethane film is prepared by two steps of two element solvent. The scanning electron microscope, infrared spectra, thermal properties, thermodynamic properties and mechanical properties test for different ratios of two yuan dissolve to different proportions. The structure and performance of the polyurethane film prepared by the two step method are characterized. Through the scanning electron microscope diagram of the film section, it is known that the surface of the polyurethane film is more smooth and the cross section is more compact with the increase of the proportion of toluene in the two solvent. The absorption peak near the 3300cm-1 is slightly offset to the high band through the Fourier transform infrared spectrum analysis. With the increase of the peak value, the hydrogen bond in the hard segment of the polyurethane film is weakened with the increase of the ratio of toluene in the two element solvent. Through the test of DSC and DMA, the glass transition temperature of the polyurethane material is the lowest when the proportion of toluene in the two solvent is 30%, indicating that the soft chain section of the polyurethane material becomes softer. When the proportion of toluene in two solvent is 30%, the tensile stress, tensile strain and fracture work of the polyurethane film are the largest, 27.72MPa, 2034.18% and 10.25J, respectively, 6.45 times the tensile stress of the single solvent DMF wet method, 3.18 times the tensile strain and 8.47 times the breaking work. The polyurethane film prepared by the two step method of two element solvent is about 2.11 times the tensile strain of the dry process, 2 times the breaking work, and the tensile stress is reduced, it is 78.26%. third of the dry tensile stress. The polyurethane fiber is prepared by two steps of two solvent solvent. The two step method of two yuan solvent two step by the scanning electron microscope and the mechanical properties test is carried out. The structure and properties of the prepared polyurethane fibers were characterized. Through the scanning electron microscope diagram of the film section, it was found that the cross section of the polyurethane fiber was more compact with the increase of the proportion of toluene in the two solvent, and the mechanical properties of the fibers increased with the increase of the ratio of toluene in the two solvent. When the toluene ratio is 30%, the elongation at break of polyurethane fiber reaches the maximum.

【学位授予单位】：武汉纺织大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ342;TB383.2

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