Fzbrication And Properties Of Silicon-Based Composite Hydrogel

Polymer hydrogels are sorts of soft and wet materials which contain water (50-90%) in the system. By introducing a part of hydrophobic groups and hydrophilic residues in the water soluble polymers, the water molecules are combined with the hydrophilic residues, while the hydrophobic residues are expanded in water. The unique network is flexible, maintaining certain shape even the mass of water contained. The structure endowed the materials many irreplaceable excellent properties, such as swelling/deswelling, stimulus response, shock absorption, low friction etc. These characteristics make the hydogels widely used in the field of waste treatment, agriculture, food chemistry, environmental engineering and so on. However, the traditional preparation method of chemically cross-linked hydrogels usually result in poor mechanical properties because of the crosslinking density, moisture content, the non-uniformity of the network structure and so on, greatly reducing its development in various areas. Many efforts have been made to develop new polymerization methods for preparing strong hydrogels. These developments have led to the generation of diverse and tough hydrogels, including nanocomposite, sliding ring, tetrapolyethylene glycol, macromolecular microsphere composite, and dual-component polymer hydrogels. Dual-component polymer hydrogels are represented by interpenetrating network, semi-interpenetrating, and double-network hydrogels. We report the new and simple one-pot method in this paper to synthesize a tough, highly resilient, fast-recovering, and self-healing hydrogel composed of silicone and polyhydroxyethyl acrylate (PHEA) using photopolymerization and sol-gel transition processes. The main work was as follows:(1) All reactants of HEA, photoinitiator 2959, MTMS, urea, and cetyltrimethyl ammonium bromide (CTAB) were added into one single water pot. HEA is first photopolymerized in the water solution, and the shape of the gel is fixed, the network that is physically linked by the hydrogen bond between hydroxyl groups is formed. Urea decomposes into NH3 and CO2 during the sol-gel process at 80?. NH3·H2O also catalyzes the sol-gel process, and then the silicone/PHEA network is formed.(2) The effects of different factors on the preparation of composite toughness hydrogels were analyzed by experiment and theory. The optimal experimental conditions were determined. Besides, the properties of the four kinds of silicone were compared and analyzed by using diverse characterization methods. The mechanical properties and other properties of the hydrogels can be changed by adjusting the silicone type to satisfy the demand of different application fields.(3) The properties of the composite toughness hydrogels prepared by MTMS (methacrylatesilane) and hydroxyethyl acrylate (HEA) were studied. Through a variety of characterization methods, it was found that the HEA/MTMS hydrogel possessed high mechanical strength and good ductility, even excellent resistance to fatigue. In addition, the hydrogels can self-heal because of the hydrogen bonding interactions in the network system. The new hydrogels with comprehensive mechanical property and biocompatibility are expected to be applied in biomedical materials area, especially the tissue engineering etc.