Preparation Of High Performance Hydrogels Based On Polyacrylic Acid

Polyacrylic hydrogel is one of the polymeric materials with three-dimensional network structure.It is widely favored in scientific research and application development due to its unique properties.Traditionally,polymer hydrogels with small molecular crosslinkers or covalently crosslinked often suffered low mechanical strength.Thus,preparation of high performance is also a hot issue in recent years.In this work,non-covalent interactions were introduced into our system to improve the mechanical property of PAA hydrogel.And the applications of hydrogels were researched.The main works and results are summarized as follows:1.The spherical polymer brushes consisted of a polystyrene core and poly(acrylic acid)chains was synthesized.Then,the PAA@PS were employed as macromolecular crosslinker to synthesize hydrogel.The obtained PAA/PAA@PS hydrogels combined desirable strethability,toughness,notch-insensitivity and high water-absorbing capacity.The uniaxial tensile tests show a very high fracture elongation up to 9.1 ×103%,while the compressive stress up to 1.8 MPa and the maximum swelling ratio of the hydrogel can be 2.0×103 as well.After being loaded with silver nanoparticles,the PAA/PAA@PS hydrogels were employed as a recyclable catalyst successfully.2.In order to improve the hydrogen bond in our hydrogels,amphiphilic block copolymer,polyethylene oxide-b-polyacrylamide leucine(PEO-b-PLAA),was synthesized by ATRP.Then,the PEO-PLAA were employed as macromolecular crosslinker to prepare hydrogel.The obtained PAA/PEO-PLAA hydrogels combine self-healing ability and well mechanical properties due to a large number of hydrogen bonds and physical entanglement existed in hydrogel system.And dopamine were introduced in hydrogel system to reduce the time of self-healing.3.Another amphiphilic block copolymer,polyethylene oxide-b-polyacrylamide aspartic acid(PEO-b-PAAC),was synthesized by RAFT.Then,the PEO-PAAC were employed as macromolecular crosslinker to synthesize hydrogel.The obtained PAA/PEO-PAAC hydrogels combine strethability,toughness,notch-insensitivity and high water-absorbing capacity.The uniaxial tensile tests show a very high fracture elongation up to 7.6×103%,while the compressive stress up to 3.4 MPa and the maximum swelling ratio of the hydrogel can be 1.2×103 as well.