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本文用差示扫描量热法(DSC),研究了铬鞣猪皮胶原的热变性过程。首次报导了铬鞣猪皮胶原的热变性的逐步行为,DSC曲线呈现主峰和肩蜂两个吸热效应,其中主峰峰温在100℃左右,130—150℃之间即出现一个肩峰。主峰的热效应代表天然胶原纤维,在鞣剂和其它助剂存在下,水合结晶区域的熔融转变;肩峰则归属于胶原超分子结构的变化。随着试样含水率的增加,肩峰的热效应逐渐增大;含水率达39.0％时则明显变小,含水率为58.1％时肩峰消失。考察了肩蜂热效应的不可逆性,认为这一变性过程可能涉及体系中不稳定共价交联——Schiff碱交联结构的破坏。借鉴小角x—光散射法(SAXS)测定的胶原纤维轴长间距的变化,作出了较具体的解释。另一方面,主峰可随水份的再吸附而重视,且依赖于试样损坏程度、再吸附量、再次扫描的间歇时间及环境温度,湿度等因素。
In this paper, differential scanning calorimetry (DSC) was used to study the thermal denaturation of chrome-tanned pigskin collagen. The first step was to report the gradual behavior of thermal denaturation of chrome-tanned pigskin collagen. The DSC curve showed two endothermic effects of main peak and Shoulder-bee. The peak temperature of main peak was about 100 ℃, and a shoulder peak appeared between 130-150 ℃. The thermal effect of the main peak represents the natural collagen fibers, melting transitions in the hydrated crystalline region in the presence of tanning agents and other auxiliaries; shoulder acuity is attributed to changes in the supramolecular structure of the collagen. With the increase of moisture content of sample, the thermal effect of acromion increased gradually. When the moisture content reached 39.0%, the acromion decreased obviously, and the acromion disappeared when the moisture content was 58.1%. The irreversibility of the shoulder-bee heat effect was investigated. It is considered that this denaturation process may involve the breakdown of the unsteady covalent cross-linking-Schiff base cross-linked structure in the system. A more specific explanation is given based on the changes in the axial distance of collagen fibers measured by the small angle x-ray scattering method (SAXS). On the other hand, the main peak with the re-adsorption of water and attention, and depends on the extent of damage to the sample, reabsorption, rescanning intermittent time and ambient temperature and humidity and other factors.