【作者】 熊思勇；

【导师】 李明忠；

【作者基本信息】 苏州大学 ， 纺织工程， 2010， 硕士

【摘要】 以往国内外研究者将γ-射线辐照、超声波、多元醇、剪切应力等因素对家蚕丝素蛋白结构转变的影响进行了一定程度的研究,但目前为止,国内外关于这些因素对天蚕丝素、柞蚕丝素蛋白结构转变的影响的相关研究还很少。本文主要探讨γ-射线、超声波、多元醇、剪切应力对天蚕丝素、柞蚕丝素蛋白结构转变的影响,并与这些因素对家蚕丝素蛋白结构转变的影响进行对比,初步探讨了丝素凝胶的形成机理。通过对天蚕、柞蚕、家蚕丝素膜进行XRD、FTIR、DSC及力学性能的测试,研究了γ-射线辐照对天蚕、柞蚕、家蚕丝素蛋白结构转变的影响。结果表明:经γ-射线辐照处理后的天蚕、柞蚕、家蚕丝素膜,其结晶结构及分子构象均未发生明显的改变;随着辐照剂量的增加,丝素膜的热稳定性稍有下降,断裂强度、断裂伸长率明显下降。通过对天蚕、柞蚕、家蚕丝素凝胶进行XRD、FTIR测试,研究了不同功率的超声波对天蚕、柞蚕、家蚕丝素溶液胶凝时间及对最终形成的丝素凝胶结构的影响。结果表明:对于天蚕丝素溶液,当超声波功率小于400 W时,随着功率的增大,胶凝时间减小;当超声波功率大于400 W时,随着功率的增大,胶凝时间增大。而对于柞蚕丝素溶液,当超声波的功率小于500 W时,随着功率的增大,胶凝时间减小;当超声波的功率大于500 W时,胶凝时间急剧增大。对于家蚕丝素溶液,随着超声波功率的增大,胶凝时间急剧减小。超声波作用能加快丝素溶液中丝素蛋白分子的构象由无规卷曲向β-折叠结构的转变,但对最终形成的天蚕、柞蚕和家蚕丝素凝胶的结晶结构及分子构象的影响不显著。通过对天蚕、柞蚕、家蚕丝素凝胶进行XRD、FTIR、Raman光谱测试,研究了不同添加比例的多元醇(乙二醇,聚乙二醇600)对天蚕、柞蚕、家蚕丝素溶液胶凝时间及对最终形成的丝素凝胶结构的影响。结果表明:无论是向丝素溶液中添加乙二醇还是聚乙二醇600,当添加比例小于300%时,随着添加比例的增加,天蚕、柞蚕丝素溶液胶凝时间急剧减小;当添加比例大于300%时,随着添加比例的增加,胶凝时间稍有增大。而对于家蚕丝素溶液,随着添加比例的增加,胶凝时间急剧减小。多元醇的添加能加速丝素溶液中丝素蛋白分子的构象由无规卷曲向β-折叠结构的转变,但对最终形成的天蚕、柞蚕、家蚕丝素凝胶的结晶结构及分子构象均无明显影响。当乙二醇的添加量为300%时,丝素凝胶具有较均匀的孔隙。通过对天蚕、柞蚕、家蚕丝素溶液进行CD测试及对天蚕、柞蚕、家蚕丝素凝胶进行XRD、FTIR测试,研究了剪切作用对天蚕、柞蚕、家蚕丝素溶液中分子构象、胶凝时间及凝胶结构的影响。结果表明:对于天蚕、柞蚕丝素溶液,随着剪切作用时间的增大,胶凝时间减小。而对于家蚕丝素溶液,当剪切作用时间小于45min时,随着剪切作用时间的增大,胶凝时间稍有减小;当剪切作用时间大于45min时,胶凝时间急剧减小。对于三种丝素溶液,在相同剪切作用时间时,剪切速率越大,胶凝时间亦越小;剪切作用时间越长,剪切速率越大,剪切作用后放置的时间越长,溶液中丝素分子β-折叠化的程度越高。剪切作用能加速丝素溶液中丝素蛋白分子的构象由无规卷曲向β-折叠结构的转变,但对最终形成的天蚕、柞蚕、家蚕丝素凝胶的结晶结构及分子构象均无明显影响。综上所述,γ-射线辐照处理对天蚕、柞蚕、家蚕丝素膜内分子构象及结晶结构均无明显影响,但使丝素膜的热稳定性、断裂强度及断裂伸长率下降。超声波、多元醇、剪切作用均能促进丝素溶液中丝素蛋白分子的构象由无规卷曲向β-折叠结构的转变,但对最终形成的丝素凝胶的分子构象及结晶结构均无明显影响。丝素凝胶的形成主要是丝素分子不断β-折叠化的过程。更多还原

【Abstract】 Researchers at home and abroad had studied the effects ofγ-ray irradiation, ultrasonic, polyalcohol and shear stress on the structural transformation of regenerated Bombyx mori silk fibroin, to a certain extent. But so far, the research on the structural transformation of regenerated Antheraea yamamai, Antheraea perny silk fibroin by these factors has been very rare. In this paper, we have focused on the effects ofγ-ray irradiation, ultrasonic, polyalcohol and shear stress on the structural transformation of regenerate Antheraea yamamai, Antheraea perny silk fibroin, compared with the behavior of Bombyx mori silk fibroin affected by these factors, further to discuss the formation mechanism of silk fibroin gel.The structural transformation of silk fibroin molecules in the regenerated Antheraea yamamai, Antheraea perny, Bombyx mori silk fibroin films with different doses ofγ-ray radiation treatment was studied by analyzing the experiments of X-ray diffraction, FTIR spectroscopy, Differential Scanning Calorimetry and Mechanical Properties Test. The results showed that there were not noticeable changes in the crystal structure and molecular conformation of those silk fibroin films. However, with the increase in radiation dose, the thermal stability of those silk fibroin films becomes a slight weaker, the broken strength and the broken elongation rate of those silk fibroin films decreased greatly.The effects of ultrasonic on the structural transformation of the regenerated Antheraea yamamai, Antheraea perny, Bombyx mori silk fibroin molecules were studied. The gelation time of the silk fibroin solution was determined and the structure of silk fibroin gels was analyzed by X-ray diffraction and FTIR spectroscopy. The results show that when the power was lower than 400 W, with the increase of ultrasonic power, the gelation time of Antheraea yamama silk fibroin solution decreased gradually, and when the ultrasonic power was higher than 400W, as the ultrasonic power increased, the gelation time raised slightly. When the power was lower than 500 W, with the increase of ultrasonic power, the gelation time of Antheraea perny silk fibroin solution decreased gradually. And when the ultrasonic power was higher than 500W, as the ultrasonic power increased, the gelation time also raised sharply. As the ultrasonic power increased, the gelation time of Bombyx mori silk fibroin solution decreased sharply. The ultrasonic can accelerate the gelation of silk fibroin solution and promote the structural transformation of silk fibroin molecules from random coil orα-helix toβ-sheet, but the crystal structure and molecular conformation of silk fibroin gels are not significant.The effects of polyalcohol (EG, PEG600) on the structural transformation of the regenerated Antheraea yamamai, Antheraea perny, Bombyx mori silk fibroin molecules were studied. The gelation time of the silk fibroin solution was determined and the structure of silk fibroin gels was analyzed by X-ray diffraction, FTIR spectroscopy, Raman spectroscopy, Scanning electron microscopy. The results show that when the adding percentage is less than 300%, either EG or PEG600, with the increase in the adding percentage of polyalcohol, the gelation time of the Antheraea yamamai or Antheraea perny silk fibroin solution decreased sharply, and when the adding percentage is more than 300%, with the increase in the adding percentage, the gelation time raised slightly. The gelation time of the Bombyx mori silk fibroin solution dropped sharply with the increase in the adding percentage. Polyalcohol can accelerate the gelation of silk fibroin solution and promote the structural transformation of silk fibroin molecules from random coil orα-helix toβ-sheet, but the crystal structure and molecular conformation of silk fibroin gels are not significant by the polyalcohol. When the adding percentage of EG was 300%, the silk fibroin gel has relatively uniform pores.The effects of shearing force on the structural transformation of the regenerated Antheraea yamamai, Antheraea perny, Bombyx mori silk fibroin molecules were studied by X-ray diffraction, FTIR spectroscopy and Circular Dichrosim, and the gelation time of the silk fibroin solution was determined. The results show that the gelation time of the Antheraea yamamai or Antheraea perny silk fibroin solution decrease sharply with the increase in the shearing time. When the shearing time is less than 45 min, the gelation time of Bombyx mori silk fibroin solution decreases slightly with the increase in the shearing time, but when the shearing time is more than 45 min, the gelation time dropped sharply. The longer the shearing time or the bigger the shear rate or the longer the positioned time, the bigger the percentage ofβ-sheet silk fibroin in solution. Shearing force can accelerate the gelation process of silk fibroin solution and promote the structural transformation of silk fibroin molecules from random coil orα-helix toβ-sheet, but the crystal structure and molecular conformation of silk fibroin gels are not significant.In summary, silk fibroin films withγ-ray irradiation treatment have no changes in the molecular conformation and crystal structure, but the mechanical properties of those films become weaker. Ultrasonic, polyalcohol and shearing force can accelerate the gelation of silk fibroin solution and promote the structural transformation of silk fibroin molecules from random coil orα-helix toβ-sheet, but the crystal structure and molecular conformation of silk fibroin gels are not significant changed. The formation of silk fibroin gels mainly contains aβ-sheet process of silk fibroin molecules.更多还原