Son Dongwan, Hwang Hwanmin, Fontenot Jake F, Lee Changjae, Jung Jangwook P, Kim Myungwoong
Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea.
Department of Biological Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
ACS Omega. 2022 Aug 17;7(34):30028-30039. doi: 10.1021/acsomega.2c03031. eCollection 2022 Aug 30.
We demonstrate the impact of engineering molecular structures of poly(acrylamide) (PAAm) and poly(-isopropylacrylamide) (PNIPAm) hydrogel composites on several physical properties. The network structure was systematically varied by (i) the type and the concentration of difunctional cross-linkers and (ii) the type of native or chemically modified natural polymers, including sodium alginate, methacrylate/dopamine-incorporated porcine skin gelatin and fish skin gelatin, and thiol-incorporated lignosulfonate, which are attractive biopolymers generated in pulp and food industries because of their abundance, rich chemical functionalities, and environmental friendliness. First, we added cross-linking agents of varying lengths at different concentrations to assess how the cross-linking agent modulates the mechanical properties of acrylamide-based composites with alginate. After chemically modifying gelatins from fish or porcine skin with methacrylate and/or dopamine, the acrylamide-based composites were fabricated with the chemically modified gelatins and thiolated lignosulfonate to assess the stress-strain behavior. Furthermore, swelling ratios were measured with respect to temperature change. The mechanical properties were systematically modulated by the changes in the molecular structure, that is, the length of the chemical unit between two end alkene groups in the difunctional cross-linker and the types of the additive natural polymers. Overall, PAAm hydrogel composites exhibit a significant, negative correlation between toughness and the volume fraction of the swollen state and between strain at fracture and the volume fraction of the swollen state. In contrast, PNIPAm hydrogel composites showed positive, but only moderate correlations, which is attributed to the difference in the network polymer structure.
我们展示了聚（丙烯酰胺）（PAAm）和聚（N-异丙基丙烯酰胺）（PNIPAm）水凝胶复合材料的工程分子结构对几种物理性质的影响。通过以下方式系统地改变网络结构：（i）双官能交联剂的类型和浓度，以及（ii）天然或化学改性天然聚合物的类型，包括海藻酸钠、甲基丙烯酸酯/多巴胺掺入的猪皮明胶和鱼皮明胶，以及硫醇掺入的木质素磺酸盐，这些都是在纸浆和食品工业中产生的有吸引力的生物聚合物，因为它们丰富、具有丰富的化学官能团且环境友好。首先，我们添加不同浓度的不同长度的交联剂，以评估交联剂如何调节基于丙烯酰胺的复合材料与海藻酸盐的机械性能。在用甲基丙烯酸酯和/或多巴胺对鱼皮或猪皮明胶进行化学改性后，用化学改性的明胶和硫醇化木质素磺酸盐制备基于丙烯酰胺的复合材料，以评估应力-应变行为。此外，测量了相对于温度变化的溶胀率。机械性能通过分子结构的变化进行系统调节，即双官能交联剂中两个末端烯烃基团之间化学单元的长度和添加剂天然聚合物的类型。总体而言，PAAm水凝胶复合材料在韧性与溶胀状态的体积分数之间以及断裂应变与溶胀状态的体积分数之间呈现出显著的负相关。相比之下，PNIPAm水凝胶复合材料显示出正相关，但只是中等程度的相关，这归因于网络聚合物结构的差异。
