Functionalization of Graphene Nanoplatelet and the Shape Memory Properties of Nanocomposite Based on Thermoplastic Elastomer Polyurethane/Poly(vinyl chloride)/Graphene Nanoplateletes

In this study, shape memory polymers (SMPs) based on thermoplastic polyurethane/ poly(vinylchloride)/ graphen nanoplatelet (TPU/PVC/GNP) were produced via solution method using tetrahydrofuran(THF) solvent. Blend ratio of the all samples was 60/40 (w/w) and GNP concentration were 0.5, 1 and 2 W.t% from neat and functionalized GNP. In order to get better dispersion of GNP and inhibit from their agglomeration, functionalization with polycaprolactam was accomplished. At first, nanoparticles were treated with nitric acid and in the next step acylation was done using tionylcholride and finally polycaprolactam was grafted on the surface of nano platelet graphen. The functionaliztion reactions were tracked using fourier transfer infra red (FTIR), thermal gravimetric analysis (TGA) and ultraviolet chromatography.The results of these tests showed the successful reaction has been occurred and polycaprolactam was grafted on the surface of GNP. The presence of new peaks in FTIR spectra at 1165 and cm-1 and the loss weight in TGA by 10 and 30wt. % for modified nanoparticles in comparison to pristine one revealed the successful occurrence of modifications reaction reactions.Morphology of the samples was studied using scanning electron microscopy (SEM) and the results depicted that a fine dispersion of graphen nanoplatelet was obtained in comparison to samples including unfunctionalized nanoparticles. Shape memory induction and the measurement of shape fixity and shape recovery were done using thermal-mechanical analyzer (TMA). The results showed that the shape fixity was increased from 76.8 to 83% and shape recovery was increased from 81.5 to 86.7% for the sample containing modified GNp due to better dispersion of the nanoparticles.