Preparation And Performance Research Of PNIPAM-based High Strength Hydrogels

Hydrogel is a kind of functional polymer material with high water absorbability,good biocompatibility and stimulus response ability,which has been widely used in tissue engineering,drug delivery,wastewater treatment,chemical devices,supplies,and other fields.But traditional hydrogel is fragile and has slow response rate,which seriously limits the application range of hydrogels.So the present research mainly focused on accelerating the response rate and improving the mechanical property of hydrogel.In this paper,different modification methods were adopted to synthesize nanocomposite hydrogels,porous hydrogels and interpenetrating network hydrogels.The swelling properties and mechanical properties of novel hydrogels were studies.The main content are as follows:1.Using free radical solution polymerization,acrylolsobutyl polyhedral oligomeric silsesquioxane(MAPOSS)and poly(ethylene glycol)diacrylate(PEGD)are added to the N-isopropylacrylamide(NIPAM)matrix to synthesize nanocomposite hydrogels.The compression strength of hydrogels significantly increased with the increase in MAPOSS and PEGDA.When MAPOSS and PEGDA were the maximum content at the same time,the compression strength of hydrogel reached maximum value of 368.32 kPa.In addition,a higher deswelling rate of hydrogel was associated with the increasing introduction of MAPOSS and decreasing introduction of PEGDA.Hydrogel with the most MAPOSS content and the least PEGDA content displayed the fastest deswelling rate,expelling 60.7 % water molecules within 30 min.2.Polyethylene glycol(PEG),acting as pore-forming agent,was added to P(NIPAM-co-MAPOSS)nanocomposite hydrogels.The pore structure of hydrogel without PEG almost could not be see.While the pore structure of hydrogel containing 0.3g PEG is very clear.The addition of PEG contributed to produce more holes,and the average pore diameter increased with the increase of PEG content.The compression modulus of hydrogels firstly increased and then decreased as the PEG content increased,and hydrogel with 0.1g PEG displayed the best mechanical property.The deswelling rate of hydrogel increased with the increasing introduction of PEG.With 5-fluorouracil(5-FU)as model drug,the drug release could be controlled by adjusting the content of PEG.3.Using cross-linking reaction and interpenetrating polymer networks(IPN)technology,polyvinyl pyrrolidone(PVP)was introduced into P(NIPAM-co-AA)network to prepare temperature/pH double sensitivity P(NIPAM-co-AA)/PVP semi-IPN hydrogel.Compared to hydrogel without PVP,the melting temperature of hydrogel containing 0.1g PVP displayed a modest increase,up to 215°C.The compressive tangent modulus of hydrogel without PVP with 20% strain is 0.24 MPa.Higher compressive tangent modulus value(0.36 MPa)is obtained for hydrogel containing 0.1g PVP,indicating that the formation of IPN structure contributed to improve the mechanical properties of hydrogels.With 5-FU as model drug,the sustained drug release time of hydrogel containing 0.1g PVP reached 9 hours and cumulative drug release reached 84.5%.