Using 2-methyl-2-acrylamidopropanesulfonic acid sodium salt (NaAMPS),polyvinyl alcohol (PVA),and carboxymethyl cellulose (CMC) as raw materials,N,N′-methylene bisacrylamide as the cross-linking agent and 2-oxoglutaric acid as the initiator,the first network of the gel was formed by UV light triggered chemical cross-linking of NaAMPS.Cyclic freezing-thawing method was used to form the second network of the gel by hydrogen bonding between PVA chains.The third gel network was formed by ionic complexation between Al3+ and carboxyl groups of CMC,and the PNaAMPS/PVA/CMC-Al3+ composite hydrogel was successfully prepared.The microscopic morphologies of the gels were characterized and the mechanical properties of the gels were tested.The results showed that the internal network of the hydrogels became denser after the formation of the first and second networks,and the formation of hydrogen bonds between PVA chains increased the fracture strength from 14kPa to 53kPa.The formation of the third network of CMC-Al3+ increased the fracture strength to be 127kPa.In addition,N-isopropyl acrylamide (NIPAM) was added to the gel as a pre-polymerization monomer,and the gel exhibited a self-enhancement of fracture strength after mechanical training,with an enhancement of fracture strength of 23% at the mechanical training strain of 40%,and the fracture strength enhancement of 56% as the mechanical training strain increased from 40% to 160%.This hydrogel achieved the self-reinforcement of mechanical properties through the mechanical training-induced structural damage and reconstruction process,which broadened the practical applications in various fields and could lay the foundation for self-reinforced materials used in applications such as soft robots and smart devices.
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基金资助
山西省自然科学基金项目(2021-0302123158);山西浙大新材料与化工研究院技术开发项目(2022SX-TD023)
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