Evaluation of Intermolecular Interactions in the PHB/ZnO Nanostructured Materials

Unmodified zinc oxide nanoparticles were added to poly (3-hidroxybutyrate) matrix in four different PHB/ZnO ratios: 99.9/0.1, 99.75/0.25, 99.5/0.5 and 99/1. The method used to obtain the nanostructured materials was solvent casting, employing chloroform as solvent. The nanomaterials obtained were analysed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) relaxometry using low-field NMR, through the determination of proton spin-lattice relaxation time, with T1H as a time constant. This parameter allows us to evaluate the domain formation in the nanometer size scale, due to the new molecular arrangements promoted by zinc oxide nanoparticles dispersion and distribution process. All results, especially the ones obtained from relaxation time, indicated that the nanomaterial formed presented a good dispersion and distribution of the nanoparticle in the polymer matrix, due to the good interaction formed between polymer matrix and nanoparticle, breaking polymer-polymer and nanoparticle-nanoparticle intermolecular interaction creating new and strong interactions among polymer chains and nanoparticles with just 0.1% wt. of unmodified ZnO.