Dept. of Mechanical Engineering, Koç University, Rumelifeneri Yolu, Sariyer, 34450, Istanbul, Turkey.
Dept. of Chemistry, Faculty of Science and Letters, Istanbul Technical University, Maslak, 34467, Istanbul, Turkey.
J Mech Behav Biomed Mater. 2019 Dec;100:103374. doi: 10.1016/j.jmbbm.2019.103374. Epub 2019 Jul 27.
The control of viscoelastic properties of alginate biopolymer that mimics the matrix properties of biological substrates plays an important role for the success of its biomedical applications. For this purpose stress relaxation behavior of glycerol plasticized sodium alginate films is characterized at room temperature as a function of the glycerol concentration ranging up to 40%. A series of experiments are thus conducted at relative humidity levels of 38 ± 1% and 51 ± 1%. The glycerol content is demonstrated to amplify the effect of humidity on relaxation profiles. In the case of 30% glycerol, normalized stress at the level of 65% is recorded at the end of the first 30 min at the low humidity level, whereas the corresponding value drops to 8% with increased humidity. Alginate films with no glycerol content exhibit much higher normalized stresses of 89% and 73% at low and high humidity levels, respectively. In addition, stress relaxation is observed to continue well beyond the first 30 min, especially for glycerol concentrations lower than 30%, where 9-hour parameters for a stretched exponential Kohlrausch - Williams - Watts function are reported demonstrating the importance of relaxation time for successful modeling.
控制藻酸盐生物聚合物的黏弹性，使其模拟生物基质的特性，对于其在生物医学应用中的成功至关重要。为此，研究了室温下甘油增塑的海藻酸钠薄膜的应力松弛行为，甘油浓度范围高达 40%。因此，在相对湿度为 38±1%和 51±1%的水平下进行了一系列实验。结果表明，甘油含量放大了湿度对松弛曲线的影响。在 30%甘油的情况下，在低湿度水平下的最初 30 分钟结束时，记录到 65%水平的归一化应力为 89%，而随着湿度的增加，该值下降到 8%。不含甘油的海藻酸盐薄膜在低湿度和高湿度水平下分别表现出更高的归一化应力，分别为 89%和 73%。此外，应力松弛被观察到在最初的 30 分钟之后继续进行，特别是对于甘油浓度低于 30%的情况，其中报告了拉伸指数科勒拉乌斯-威廉姆斯-瓦特函数的 9 小时参数，这表明松弛时间对于成功建模的重要性。
