A novel fabrication method of temperature-responsive poly(acrylamide) composite hydrogel with high mechanical strength

• Published in: Polymer (Guilford) Vol. 54; no. 21; pp. 5830 - 5838
• Main Authors: Li, Pengchong, Xu, Kun, Tan, Ying, Lu, Cuige, Li, Yangling, Wang, Pixin
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 04.10.2013; Elsevier
• Subjects: acrylamides; ambient temperature; Applied sciences; Composite hydrogels; crosslinking; energy; Exact sciences and technology; Forms of application and semi-finished materials; gels; High mechanical strength; hydrocolloids; mechanical properties; microstructure; Polymer industry, paints, wood; polymerization; polymers; Reinforced plastics; rheology; Technology of polymers; Temperature-response; transmittance; water transportation; High mechanical strength; Temperature-response; Composite hydrogels; Viscoelasticity; Swelling; Filled polymers; Stress strain relation; Crosslink density; Mechanical properties; Temperature effect; Experimental study; Grafting; Acrylamide derivative polymer; Colloidal gel; Acrylamide; Cloud point; Compressive stress; Vinyl amine polymer; Morphology; Preparation; Concentration effect; Acrylamide polymer; Microgel; Bulk modulus
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2013.08.019

High strength, stimuli-responsive poly(acrylamide) composite hydrogels (PAAm CH gels) were prepared by grafting polymerization of acrylamide (AAm) onto temperature-sensitive core–shell microgels. These microgels, composing of poly(N-isopropylacrylamide) as core and polyvinylamine (PVAm) as shell, were used as both initiator and crosslinker to form a robust three-dimensional network via bonding the poly(acrylamide) (PAAm) backbone. The CH gels exhibited a remarkably rapid shrinking rate and transmittance switch in response to the environmental temperature change, which the conventional chemically cross-linking PAAm hydrogels (PAAm OR) were short of. Even compared to the bulk PNIPAAm hydrogels (PNIPAAm OR) crosslinked with N,N′-methylenebisacrylamide (MBA), the CH gels were featured with faster responsive rate, which could be attributed to the formation of interconnected water transportation channels between the microspheres and PAAm gel matrix due to the fast shrinking of microgels. Moreover, the effects of microgel species and content on swelling and mechanical properties of CH gels were also systematically investigated. The results elaborated that the CH gels could be compressed almost 99% without breaking and completely recovered their original shape when the stress was removed. And the optimized compressive strength of CH gels could be up to 21.94 MPa. Based on the analysis of CH gel mechanical properties, the influence of microsphere content on effective network chains density of CH gels was discussed through rheology measurements. Finally, the essential reinforcement on mechanical properties was mainly contributed to the homogeneous microstructure of hydrogel network and the energy dissipation mechanism of microgels in gel matrix. [Display omitted]