Preparation And Characterization Of Emulsion Composite High-strength Polyacrylamide Hydrogels

As a soft material, hydrogels has broad application on the biomedical industry and agriculture, which mainly come from artificial synthetic or natural environment. The strength of hydrogel is usually thought to be low because of large amount of water within it. But strength of natural hydrogels such as animal cartilage, muscle are very high near rubber, to make people reconsider relationship between hydrogel strength and internal structure. Therefore, to explore the relationship between internal structure and hydrogel strength, it is a very important research issue at current home and abroad.Material scientists had made great progress on high-strength hydrogel in recent years, such as double-network gel, organic-inorganic nano composite hydrogel, macromolecular microspheres composite hydrogels. But the synthesis process takes a long time, or performance of hydrogel is seriously affected by the defects of the internal structure. The approach of synthesis and the ways to high -strength gel need to be further improvement and innovation. The main purpose of this research is to prepare high -strength gel by designing of a specific cross-linking agent system. The main idea as follows:preparing un-polymeric emulsion through two different tactics, and hydrogel prepared by latex copolymerize with monomer acrylamide.1.The high strength hydrogel is prepared by copolymerizing monomer acrylamide and latex; latex comes from emulsions formed spontaneously by nano-silica and y-methacryloxypropyltrimethoxysilane (TPM); and the formation different sizes of emulsion varies with the ratio of nano-SiO2 to TPM. The emulsion stability was then observed under different conditions, and we discuss the function of different components to the pre-gel emulsion stability. High-strength gel was prepared by different concentrations and different sizes of latex with acrylamide monomer, stretching between 373～757%, the tensile strength between 70～148kPa; gel can be compressed to 80%, and compressive strength can be more than 10MPa. All above hydrogel's strength is far more than common chemical polymer hydrogel.2. The magnetic high-strength hydrogel is prepared by copolymerizing monomer acrylamide and latex; latex comes from emulsions formed spontaneously by magnetite nanoparticles and y-methacryloxypropyltrimethoxysilane(TPM). Dynamic light scattering tests showed that the emulsion particle size was within 100nm in this research, and there is close relationship between size and the ratio of TPM to Fe3O4 nanoparticles. We discuss the function of different components to the pre-gel emulsion stability. High-strength gel was prepared by different concentrations and different sizes of latex with acrylamide monomer under mild conditions. The gels can be stretching in the range of 300 to 548%, tensile strength more than 140kPa; the gels can be compressed to 80%, and compressive more than 15MPa. Compared to SiO2/TPM/AM composite gels, the overall mechanical properties have greatly improved, mainly due to more effective crosslinking density.