Study On Preparation And Properties Of Poly(N-isopropylacrylamide)/ Biomacromolecule/Graphene Oxide Composite Membrane

Currently,Poly(N-isopropylacrylamide)(PNIPAM)is one of the most widely studied thermo-responsive polymers,with the lowest critical temperature(LCST)of about 32 ?.PNIPAM is widely used in biomedical fields because of its unique temperature sensitivity.However,the practical application of traditional intelligent hydrogels is seriously restricted because of their weak mechanical strength and low biological activity.In order to solve this problem and obtain better materials,PNIPAM and the biomolecules konjac glucomannan(KGM)and carboxylated chitosan(CCS)with non-toxic,regenerated,biocompatible and biodegradable were combined with the reinforcer graphene oxide(GO)to improve the mechanical properties and biocompatibility of PNIPAM.A new thermo-sensitive PNIPAM/KGM/GO composite membrane was prepared by solution blending method,and the reaction mechanism of PNIPAM/KGM/GO was discussed.By controlling the content of PNIPAM and KGM,the effects of morphology,mechanical properties,swelling and biodegradability of PNIPAM/KGM/GO composite membrane with different contents of GO were studied.The results showed that GO was uniformly dispersed in polymer matrix after crosslinking reaction with PNIPAM/KGM and GO did not affect the overall structure of the composite membrane network.The PNIPAM/KGM/GO composite membrane showed a three-dimensional porous structure,and the pore size gradually became denser with the increase of GO.Compared with the PNIPAM/KGM binary composite membrane,the incorporation of GO can increase the swelling rate of the PNIPAM/KGM/GO composite membrane,but with the increase of GO content,the network structure of the composite membrane will be more compact.The introduction of GO can enhance the water retention rate of the composite membrane,and the water retention rate of the composite membrane increased with the increase of GO content.The mechanical properties of PNIPAM/KGM/GO composite membrane were improved by adding GO,when the content of GO was increased from 0 mg to 3 mg,The tensile strength of the composite membrane was increased from 4.85 MPa to 9.86 MPa(2.03-fold).The Young's modulus of the composite membrane was increased from 57.88 MPa to 385 MPa(6.66-fold increase).However,the increase of GO content also resulted in some defects,making PNIPAM/KGM/GO exist brittleness.Compared with the external force report of human skin,the mechanical properties of the composite membrane are within the range of the external force that the human skin can bear.The enzymatic degradation experiment shows that the composite membrane can be degraded by ?-mannanase.With the increase of enzyme concentration from 0.2 mg mL-1 to 0.4 mg mL-1,the enzymatic degradation rate increased from 58%to 70%,46%to 60%?65%to 79%?62%to 75%and 60%to 72%,respectively.And the degradation rate of PNIPAM/KGM/GO composite membrane gradually decreased with the increase of GO content.However,the enzyme degradation rate of the composite membrane was higher than that of the KGM and PNIPAM/KGM composite membranes.A new temperature/pH sensitivity PNIPAM/CCS/GO composite membrane was prepared by one step synthesis method,and the reaction mechanism of PNIPAM/CCS/GO was discussed.The content of PNIPAM was fixed by single factor variable,the optimum amount of CCS was found by DSC test,and the contents of PNIPAM and KGM were fixed.The effects of GO content on the morphology,swelling property and drug release rate of PNIPAM/CCS/GO composite membrane were studied,and the effects of different temperature and pH on the swelling property and drug release rate of PNIPAM/CCS/GO composite membrane were investigated,thereby further determining the optimal conditions for drug release.The results showed that GO was uniformly dispersed in polymer matrix GO did not affect the overall structure of the composite membrane network.With the addition of a small amount of GO the PNIPAM/CCS1.5/G02 composite film and PNIPAM/CCS1.5/G04 composite film with smooth surface without folds.and porous structure.With the increase of GO content,the composite membrane pores gradually decreased and even disappeared,and presenting flake phenomenon.Composite membrane has the obvious phase transition behavior before and after 34 ?.The swelling rate of PNIPAM/CCS 1.5/GO composite membrane is affected by temperature and pH.At room temperature,the swelling rate of PNIPAM/CCS 1.5/GO composite membrane decreases with the increase of swelling temperature.When pH=1.0,the swelling rate of the composite membrane is between 14 and 24,pH =2.0,the swelling rate of the composite membrane is the lowest(SR? 4),and the swelling ratio increases with the increase of pH value,pH=7.0,the highest swelling rate of the composite membrane is between 15 and 35.The swelling rate of the composite membrane increased gradually,and the water retention rate of the composite membrane increased with the increase of GO content.The effect of temperature and pH on the drug release rate of the composite membrane was obviousand the optimum conditions of drug release were pH 7,0 and temperature 25 ?.Based on the above analysis,the method for preparing the PNIPAM/KGM/GO and PNIPAM/CCS 1.5/GO composite membranes is a simple,controllable method,and the composite membrane is expected to be used in biomedical fields,such as skin dressing and drug release.