【作者】 贾鹏翔；

【导师】 汤克勇；

【作者基本信息】 郑州大学 ， 皮革化学与工程， 2006， 硕士

【摘要】 本文系统研究了鞣制、复鞣、加脂等工艺过程以及湿含量等对皮胶原纤维力学行为、干热稳定性和通透性能的影响，采用X-射线衍射、DSC等方法研究了在这些过程中其聚集态结构发生的变化。结果发现，皮革内部有两相，一相为较规整的结构，另一相为无序态结构。皮革内部规整结构的尺寸较小，仅2nm左右，其有序程度远远小于小分子晶体。证明关于皮革“核壳”结构的理论是合理的。皮革经鞣制后耐热稳定增加，模量降低，孔隙率增加，透水汽性增加而吸水性减小。经鞣制后，皮革内部有序结构的尺寸减少，结晶度降低，纤维间距离变大。复鞣后，皮革热稳定性有所增加，且随着复鞣剂用量的增加收缩温度提高。复鞣使皮革内晶体尺寸减少，结晶度降低，即复鞣降低了皮革内结晶部分的有序程度，使胶原纤维分子链之间的距离变小，皮革内部结构的均一程度增加。加脂后皮革的模量降低，断裂伸长率有所增加，孔隙率减小，透水汽性变差而吸水性增加。加脂使皮胶原纤维内部有序结构的尺寸减少，结晶度减低，分子链间距离有所增加。鞣制、复鞣和加脂并不能改变胶原蛋白的三股螺旋结构。湿含量的增加使皮胶原纤维的干热稳定性下降。水分的存在对胶原分子的三股螺旋结构没有影响，但相对湿含量的增加使皮胶原纤维内部的有序态结构增多，对其聚集态结构则有较大影响。 本文还对复鞣、加脂皮胶原纤维进行了TG分析，采用Flynn-Wall-Ozawa法和Satava-Sestak法计算了其热降解活化能。结果发现，复鞣和加脂后皮胶原纤维的热降解活化能与铬鞣试样相比都降低了。其原因是由于加脂以及复鞣后降低了胶原纤维内部分子间的氢键作用，削弱了分子之间的相互作用。本文还研究了未鞣皮胶原纤维在空气和氮气中的热降解行为。结果表明，在空气中，皮胶原纤维更容易降解，热降解活化能也更低。 本文还研究了皮革收缩前后力学行为、干热稳定性和通透性能的变化，采用X-射线衍射、红外光谱等方法研究了在这些过程中其聚集态结构发生的变化。结果发现，皮革收缩后，热稳定性增强，孔隙率减小，透水汽性能和吸水性都减小了，而拉伸模量和断裂伸长率都增大了。皮革发生收缩后，结晶度减小，晶体尺寸减小。收缩过程中皮革内部的氢键作用遭到破坏，收缩完成后又重新形成。鞣制、复鞣和加脂都会增加皮革的耐热收缩稳定性；加热介质的性质对皮革的收缩行为影响很大；增加皮革内部水分的含量会使其容易发生收缩。皮革收缩行为的实质是在热的作用下，氢键作用被削弱，三股螺旋结构发生破坏，肽链分子发生横向摇摆所致。收缩后分子内部在更大的范围内形成氢键作用，使整个分子形成网状交联结构。更多还原

【Abstract】 In this paper, systematic studies were done on the influence of tanning, retanning, fatliquoring and humidity content on the mechanical performance, dry heat resistance and permeability of leathers. Such methods as X-ray diffraction, differential scanning calorimetry (DSC) were employed in the analysis of the aggregation structure of leather collagen fibers and its influencing factors. The results indicate that there are two phases in the leather collagen fibers, which are ordered structure (crystalline region) and disordered structure (amorphous region). The dimension of the ordered structure is about 2 nm, which proved that the "nuclear-shell structure" of the leather collagen fibers is reasonable. When leathers are tanned, their dry heat resistance, aperture ratio and water vapor permeability increase, while the tensile modulus, water absorption and crystallinity of leathers decrease. The dry heat resistance of leather collagen fibers increases, and the crystallinity decreases after being retanned. The homogeneity of leathers is increased after being retanned. After being fatliquored, the leathers show decreased dry heat resistance, aperture ratio, water vapor permeability and crystallinity, but the water absorption and elongation at break increase. The triple helix structure showed no change after such processes as tanning, retanning and fatliqoring. The dry heat resistance decreases and the crystalline region increases with the increase of the humidity content of the leathers.In this paper, the thermal degradation behavior of retanned and fatliquored samples are studied by thermogravimetry. The thermal degradation activation energies of these samples are obtained. The results indicate that, for both processes of retanning and fatliquoring, the thermal degradation activation energies are decreased. The reason may be that the hydrogen bonds between collagen fibers are broken in the two processes. The influence of atmosphere on the thermal degradation behavior and thermal degradation activation energy of untanned collagen fibers are discussed. The results indicate that, the thermal degradation is easier to happen in air atmosphere,更多还原