Preparation Of Aqueous Graphene/water-borne Polyurethane Composites With Enhanced Properties

The purpose of this paper is to improve the water solubility of graphene, so that graphene can be uniformly dispersed in water-based polyurethane, thereby improving the property of polyurethane materials. Polyurethane/graphene composites with different graphene contents were prepared by solution mixing method, and then The structure and properties were received by infrared, XRD, transmission electron microscopy and other methods. The main contents are as follows:1)The graphene oxide was surface-modified with a polyoxyethylene-polydimethylsiloxane copolymer (PEG-b-PDMS-b-PEG, hereinafter referred to as PEPS), reduced by hydrazine hydrate to prepare a Water-dispersible functionalized graphene. Through the microstructure analysis of functionalized graphene (FGNs), it was found that FGNs were uniformly and stably dispersed in water, which prevented the accumulation of graphene. The effect of the pH value of GO on the stability of graphene oxide system was studied. It was found that the pH of GO was about 9.0,and a stable dispersion system was obtained.2) Anionic polyurethane with two kinds of particle size was prepared. The mixture of anionic polyurethane which is coarse-grained and FGNs were precipitated. The AWPU/FGNs were prepared by mixing fine-grained anionic polyurethane (AWPU)with functionalized grapheme. The results show that the flaky graphene is uniformly dispersed in AWPU by XRD, TEM and so on. TG, DSC and other analysis found that heat resistance, oxygen barrier performance of AWPU/FGNs were significantly improved. When the content of FGNs is 2.0 wt%, Compared with pure AWPU, the peak heat release rate of AWPU/FGNs is reduced by 33.4%.3) The CWPU/FGNs composite system was prepared by mixing cationicpolyurethane (CWPU) with functionalized graphene. It was found that there was electrostatic interaction between FGNs and CWPU, so FGNs could be better dispersed in CWPU matrix. TEM and SEM morphology analysis found that FGNs and CWPU has a good compatibility. The conductivity test results show that the conductivity of CWPU/FGNs is significantly higher than that of pure CWPU. The TG and DSC results show that the heat resistance, mechanical and oxygen barrier rates of CWPU/FGNs are significantly improved.