超声时间对胶原溶液流变性能的影响

Effects of Ultrasonic Treatment Time on the Rheological Properties of Collagen Solutions

5 mg/m L胶原溶液在超声条件为20 k Hz、45 W时分别处理0、5、10和30 min后,采用流变仪考察其稳态剪切、动态黏弹性、触变和蠕变性能的变化。结果表明:胶原溶液均表现出明显的假塑性,其流变学性能在超声处理10 min时已发生了显著改变,超声10 min后改变速率减缓。在超声处理10 min时和未超声处理的胶原相比,动态频率0.1 Hz处的弹性模量(G')、黏性模量(G")及复数黏度(η*)下降均超过了70%,力学损耗(tanδ)增加了42.91%,触变环面积和应变回复率分别下降了88.86%和92.56%,最大柔量增加了24.88倍。经超声处理后胶原溶液中分子的缠结程度降低,抵抗形变能力变弱,溶液的流动性能增强。

Collagen solutions of 5 mg/mL were treated under the ultrasonic？conditions of 20 kHz and 45 W for 0, 5, 10 and 30 min, respectively and then the reological properties were studied by a rheometer about the changes of the steady flow, dynamic viscoelasticity, thixotropy and creep. The results showed that all collagen solutions were obvious pseudoplastic and the rheological properties of collagen solutions were significantly changed in the first 10 rain after ultrasonic treatment and then the rate of changes relatively slowed down. After the collagen solutions were treated with ultrasonic for 10 min, compared with the collagen solution without ultrasonic treatment, the elastic modulus （G＇）, viscous modulus （G＂） and complex viscosity （ η＊ ） decreased by 70% while the mechanical loss （ tanδ ） increased by 42.91% at the dynamic frequency of 0.1 Hz. Also the area of thixotropic loop and the strain recovery rate decreased by 88.86% and 92.56% ,respectively, and the maximum of compliance increased by 24.88 times. After collagen solutions were treated with ultrasound, owing to the reduction of the entanglement of collagen molecules and the ability to resist deformation, the fluidity of collagen solutions enhanced.