Preparation Of Double Network Hydrogel With PH Response And High Strength

The main purpose of this work is to combine IPN hydrogels with nanocompositehydrogels using the method of interpenetrating polymer networks prepared with sensitiveresponse and good biocompatibility of high-strength intelligent hydrogels.The basic idea ofthe study are: ion cross-linking alginate as a network to provide responsiveness; UsingLaponite or N,N-methylene-polyacrylamide bis-acrylamide (BIS) as across-linking anothernetwork, carrying stress.By controlling the synthesis conditions, the use of two networksynergy preparing a high strength and responsive hydrogel.The main contents and the results of this experiment are as follows:1. K2S2O8used as an initiator, TEMED as an accelerator,initiator acrylamide (AM)monomer is polymerized.Using conventional chemical cross-linking agent BIScross-linked to form a network.Sodium alginate(SA)and calcium ions to form a secondphysical cross linking network to form a double network hydrogels.By changing theadjustment of the amount of Ca2+and BIS two network cross-linking density ratio tocontrol the strength of the hydrogel;By changing the content of SA to adjust the pHsensitivity.Universal electronic tensile test machine by the mechanical properties of thehydrogel,given the different ionic strength buffer of pH of water and the swelling of theimpact of the impulse response.The results of this experiment show that: SA representing0.75%(wt)overall, K2S2O8: TEMED=1:1(mol), AM: K2S2O8=1:0.25%(wt), AM: BIS=1:0.06%(wt), SA: Ca2+=1:0.06（wt）, SA and AM and the overall quality score of9%under the conditions, the system of double-network hydrogels tensile strength of up to83.88kPa.Under this condition,the tensile strength of the hydrogel single network only17.69kPa,significantly enhanced.In between pH=4-7,the degree of swelling of thehydrogel mutation showed significant pH responsiveness.pH=3and at pH=7of theimpulse response, the degree of swelling of the gel showed good reproducibility.2.Using Laponite as cross-linking agent, AM Laponite dispersion in situfree radicalpolymerization to form a first network.Sodium alginate(SA) and calcium ions to form asecond physical cross-linking network to form a double network hydrogels.Laponite bychanging Laponite adjust both the amount of Ca2+and cross-linking density than the network，controlling the intensity of the hydrogel;SA by changing the content of,adjustingthe pH sensitivity.Universal electronic tensile test machine by the mechanical properties ofthe hydrogel,given the different ionic strength buffer of pH of water and the swelling of theimpact of the impulse response.Experimental results show that: SA from0.25%of thetotal(wt), K2S2O8: TEMED=1:1(mol), AM: K2S2O8=1:0.25%(wt), Laponite=6%(wt/v), SA: Ca2+=1:0.056(wt), SA and AM and the overall mass fraction of9%under theconditions, the system of two high tensile strengthhydrogels79.8kPa.Under thiscondition,the tensile strength of a single network hydrogel only46.20kPa,while thesemi-IPN hydrogel strength70.9kPa.In between pH=4-7,the degree of swelling of thehydrogel network double mutation showed significant pH-responsive.pH=3and at pH=7of the impulse response, the degree of swelling of the gel showed good reproducibility.