Silane compatibilzation to improve the dispersion, thermal and mechancial properties of cellulose nanocrystals in poly (ethylene oxide)

Abstract

Cellulose nanocrystal (CNC) has potential to be used as a reinforcement in polymeric nanocomposites because of their inherent biodegradability, universal accessibility, and superior mechanical properties. The most crucial challenge faced in the nanocomposite production is dispersing the nanoparticles effectively in the polymer matrix, so that the exceptional mechanical properties of the nanoparticles can be transferred to the macroscale properties to the bulk nanocomposites. In this research, a safe, effective and ecofriendly modification was used to functionalize the surface hydroxyl groups of CNC via silane treatment. These modified CNCs were used as reinforcements to prepare poly (ethylene oxide) (PEO)/CNC nanocomposites. The composites were prepared using solvent casting method. The composite properties were evaluated using Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Thermo-Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Dynamic Mechanical Analysis (DMA). The SEM micrographs demonstrated that the composites incorporated with silane treated CNCs showed improvement in the dispersion behavior of the nanoparticles in the matrix. Oxidative combustion of the composites containing silane treated CNCs promoted char formation and enhanced thermal stability. The composites containing (1:1) silane treated CNCs exhibited the better crystallization ability, highest storage modulus, and lowest tan δ value compared to the other silane treated systems indicating improved dispersion of CNC. The polysiloxane network provided an efficient surface covering of the CNC molecules, imparting reduced polar surface characteristics and enhancing the overall mechanical properties of the composites.

Keywords

• cellulose nanocrystals
• poly (ethylene oxide)
• dispersion
• thermal stability
• mechanical properties
• self-condensation reaction