Preparation Of PDMAA/Graphene Nanocomposite Hydrogel

Nanocomposite hydrogel,as an important member of the hydrogel family,can exhibit excellent properties combining nano-particles and hydrogel,which can be widely applied in biomedical engineering,environmental protection,sensors and many other fields.Graphene is a typical kind of two dimensional nano-materials,which has attracted great attention since it was found because of its outstanding optical,thermal,electrical,mechanical properties,thus incorporating graphene into nanocomposite hydrogels has rencently become one hot research spot.It is worth noting that graphene is incline to agglomerate due to its higher specific surface area and the chemical inertness makes it difficult to be connected with the polymer chains when apply graphene into nanocomposite hydrogels.In order to solve this problem,we used N,N-dimethylacrylamide(DMAA)as the monomer to synthesize nanocomposite hydrogels.The strong electrostatic interaction between DMAA and graphene has a dual effect: on the one hand,it greatly improves the dispersibility of graphene in the hydrogel system,on the other hand,it also makes the graphene and the polymer chain effectively connected,which enhances the crosslinking effect of graphene in the composite hydrogel system.In addition,to improve the mechanical strength of PDMAA/graphene nanocomposite hydrogels,the N,N-methylene bisacrylamide(BIS)was used as organic crosslinking agent,whose best dosage was confirmed as 0.4% of the mass fraction by optimization experiments.In this paper,we prepared PDMAA/graphene nanocomposite hydrogels by in-situ radical polymerization.Then,the influences of graphene content on the formation and corresponding properties of PDMAA/graphene nanocomposite hydrogels with the fixed BIS content were detaily investigated.The SEM confirmed the homogeneous stable dispersion of graphene in the composite hydrogel system.At the same time,the interaction between graphene and DMAA was verified by rheological test,UV-visible spectroscopy and 1H-NMR.According to the results,we found that 1.0% of the graphene content is the best value to form nanocomposite hydrogels,that is,the mechanical,swelling and conduction properties of the hydrogels increased gradually with the increase of graphene content when the mass fraction range was 0%-1.0%,however,when the graphene content was more than 1.0%,the corresponding properties showed a decreasing trend.Compared with PDMAA hydrogel without graphene,the tensile strength,elongation at break,swelling ratio,and thermal conductivity of PDMAA/graphene nanocomposite hydrogel at 1.0% graphene content were increased by 88%,60%,29%,0.073 W/m·K,respectively.Therefore,the results of this paper provide a good theoretical basis for the preparation of graphene-based nanocomposite hydrogels,thus show a good application prospect and potential in biomedical and sensor fields.