Phase Transition Temperature Controllable Poly(acrylamide-co-acrylic acid) Nanocomposite Physical Hy

• 作 者: Li-qin Zhang Li-wen Chen Ming Zhong Fu-kuan Shi Xiao-ying Liu 谢续明
• 机 构: Laboratory of Advanced Materials(MOE),Department of Chemical Engineering,Tsinghua University,
• 出 处: Chinese Journal of Polymer Science
• 发表日期: 2016年10期
• 关键词: acrylamide hydrogel acrylic monomer chains polymerization grafted analogous fabr

Poly(acrylamide-co-acrylic acid) nanocomposite physical(P(AAm-co-AAc)NCP) hydrogels have been prepared through the in situ free radical solution polymerization based on a “single network, dual cross-linkings” strategy. The P(AAm-co-AAc) NCP hydrogels are composed of nanobrushes of P(AAm-co-AAc) chains grafted on the surface of vinylhybrid silica nanoparticles(VSNPs). In the hydrogel system, the VSNPs act as the “analogous chemical cross-linking points”once the hydrogen bonds formed between the P(AAm-co-AAc) chains of the nanobrushes, thus leading to the fabrication of high-strength P(AAm-co-AAc) NCP hydrogels. Compared with conventional thermosensitive P(AAm-co-AAc) hydrogels,the P(AAm-co-AAc) NCP hydrogels have a broader range of phase transition temperature, which can be adjusted by altering the monomer ratio, the VSNPs concentration, the addition of urea and N,N-dimethylacrylamide(DMAAm). At the same time, the mechanical properties of the P(AAm-co-AAc) NCP hydrogels have been improved significantly by the introduction of VSNPs. Furthermore, both the phase transition and the tensile strength of the P(AAm-co-AAc) NCP hydrogels are largely influenced when Fe3+ ions are introduced as the ionic crosslinkers into the hydrogel networks.

Poly (acrylamide-co-acrylic acid) nanocomposite physical (P (AAm-co-AAc) NCP) hydrogels have been prepared through the in situ free radical solution polymerization based on a “single network, dual cross-linkings” strategy. In the hydrogel system, the VSNPs act as the “analogous (AAm-co-AAc) chemical cross-linking points ”once the hydrogen bonds formed between the P (AAm-co-AAc) chains of the nanobrushes, thus leading to the fabrication of high-strength P (AAm-co- AAc) NCP hydrogels. The thermosensitive P (AAm-co-AAc) hydrogels, the P (AAm-co-AAc) NCP hydrogels have a broader range of phase transition temperatures, which can be adjusted by altering the monomer ratio, the VSNPs concentration, the addition of urea and N, N-dimethylacrylamide (DMAAm). At the same time, the mechanical properties of the P (AAm-co-AAc) NCP hydrogels have been im significantly significantly by the introduction of VSNPs. Both, the phase transition and the tensile strength of the P (AAm-co-AAc) NCP hydrogels are largely influenced when Fe3 + ions are introduced as the ionic crosslinkers into the hydrogel networks.