Influence of graphene oxide on ‘in situ’ preparation of nanocomposites with polyvinyl butyral

In this work, polyvinyl butyral (PVB) nanocomposites reinforced with 0.5 to 2.5 wt% of graphene oxide(GO) were synthesized via „in situ‟ polymerization. PVB was obtained by condensation of hydroxyl groupsof polyvinyl alcohol (PVA) with butyraldehyde (BU) Thermogravimetric analyzes (TGA) showed the increasein the thermal conductivity of the nanocomposites compared to PVB. FTIR results showed the conversionof PVA to PVB, but no changes in the spectrum were observed for nanocomposites. Nuclear magneticresonance spectroscopy (1H NMR) shows a change in the degree of acetalization of PVB with the presence ofthe nanoparticles. When the increase in the concentration of GO, a decrease in the degree of acetalization ofPVB is observed. The differential scanning calorimetry (DSC), show a decrease in Tg values, probablycaused by the change of degree of acetalization. The results of the Raman spectroscopy analysis show upshiftin the G band up to 20 cm-1, associated with the presence of van der Walls interaction between the GO andPVB and the mechanical compression phenomena of the GO nanoparticles are compressed in the „bulk‟ ofpolymer. Thus, it was observed that the „in situ‟ polymerization process contributed to the formation of acolloid between GO and water used as solvent in the synthesis. The formation of this colloid helped to improvethe interfacial interaction between GO and PVB. However, the presence of GO also contributed tochange the degree of acetalization of PVB, as it decreased the condensation of some hydroxyl groups of theprecursor PVA degree of acetalization.Keywords: polyvinyl butyral, graphene oxide, nanocomposites