Preparation and properties of MWCNTs reinforced polyethylene glycol-polyvinyl alcohol composite hydrogel

Carboxy-functionalized multi-walled carbon nanotubes(MWCNTs)/polyethylene glycol (PEG)-poly-vinyl alcohol (PVA) composite hydrogels were prepared by the freezing/thawing method. The microstructure, swelling property, tensile strength, thermal stability and conductivity of MWCNTs/PEG-PVA composite hydrogels with different mass ratios were studied. The results show that the MWCNTs/PEG-PVA hydrogel still has a porous 3D structure, but the pore size becomes smaller after the addition of MWCNTs. When the mass ratio of MWCNTs to PVA is larger than 1.0:100, the uniformity of the porous structure of the MWCNTs/PEG-PVA hydrogel decreases. With the increment of MWCNTs content, the swelling degree and tensile strength of the MWCNTs/PEG-PVA composite hydrogel increase first and then decrease. When the mass ratio of MWCNTs to PVA is 1.0:100, the swelling degree and porosity of the MWCNTs/PEG-PVA hydrogel reach the maximum (1450% and 75.8%, respectively). The tensile strength and elongation reach a maximum value of 0.97 MPa and 384.0%, respectively. The addition of MWCNTs improves the thermal stability of the composite hydrogel, and the initial thermal decomposition temperature of MWCNTs/PEG-PVA composite hydrogel increases from 235℃ to 260℃. With the increment of the amount of MWCNTs, the conductivity of the composite hydrogel increases from 1.10×10^-6 S/cm to 6.96×10^-4 S/cm.