The Preparation Of PH And Temperature Dual Response Hybrid Hydrogels

Hydrogel is a kind of three-dimensional polymer material with high water content.It is widely used in biology,medicine,agriculture and so on.However,the application of traditional hydrogels which crosslinked by chemical crosslinker are limited due to its uneven crosslinking structure and poor mechanical properties.In this thesis,nano composite gel is combined with double networks to prepare Intelligent hydrogels with high strength,and explored the mechanical properties,p H response and temperature response of the double network hydrogel.The main contents and results are as follows:1.The preparation of polyacrylamide/poly?2-dimethyl amino?ethyl methacrylate?PAM/PDMAEMA?double network hydrogels.We used a two-step method for preparing the Interpenetrating Polymer Network double network hydrogels,first,with Laponite as crosslinkr sythesising PAM hydrogel and then using the BIS as crosslinkr sythesising PDMAEMA hydrogel.Through studying the monomer ratio of AM and DMAEMA,crosslinking density,the molar ratio of K₂S₂O₈ and TEMED in the network,synthesis the high tensile srength and pH responsive double network hydrogels.The results show that when AM:DMAEMA=1:1?wt?,K₂S₂O₈:TEMED=1:0.7?moL?,DMAEMA:BIS=1:2%?wt?,AM:Laponite=1:70%?wt?,the tensile strength of the hydrogel can reach55KPa with a p H response.2.The preparation of poly?N-isopropylacrylamide?/polacrylic acid sodium?PNIPAm/PAANa?double network hydrogels.Laponite crosslinked poly?N-isopropylacrylamide??PNIPAm?was used as the first network to synthesize interpenetrating polymer networks,PAANa which was crosslinked with N,N-methylenebisacrylamide.The tensile strength,pH response and temperature sensitivity of the hydrogels were investigated by changing the monomer ratio,the crosslinking density and the neutralization degree of acrylic acid.The results show that the low critical solution temperature of PNIPAm/PAANa double network hydrogel is 34?,it has good mechanical strength and pH sensitivity.3.The preparation of poly?N-isopropylacrylamide?/poly(?2-dimethyl amino?ethyl methacrylate?PNIPAm/PDMAEMA?double network hydrogels.We used Laponite cross-linked poly N-isopropyl acrylamide?PNIPAm?as the first network,and N,N-methylenebisacrylamide?BIS?cross-linked poly?2-dimethyl amino?ethyl methacrylate?PDMAEMA?synthesis the interpenetrating double network hydrogels.By changing the amount of monomer and the amount of crosslinking agent,the tensile strength,the pH and temperature response of the double network hydrogel were investigated.The results show that the low critical transition temperature of PNIPAm/PDMAEMA double network hydrogels is 33?,and has good mechanical properties and pH response.