Evaluation of the effect of isocyanate modification on the thermal and rheological properties of poly(ε-caprolactone)/cellulose composites

Nanocellulose obtained with acid hydrolysis method using microcrystalline cellulose (MCC) was chemically modified with n-octadecyl isocyanate. Nanocellulose (NC), isocyanate modified nanocellulose (ISO-NC) and MCC were added to poly(ε-caprolactone) (PCL) in order to produce composites by solvent casting method. Transmission electron microscopy (TEM) images showed that diameter of nanofibers ranged from 10 to 20 nm. The surface chemical modification of nanocellulose was characterized by Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). In order to understand the effect of cellulose content and modification on the performance of PCL/cellulose composites, surface morphologies, contact angle, thermal and rheological properties of the composites were investigated. The surface chemical modification with n-octadecyl isocyanate improved distribution of NC in PCL matrix. The dynamic mechanical and rheological properties of neat PCL were greatly improved by the addition of ISO-NC with respect to untreated NC and MCC due to the excellent interfacial compatibility between PCL and ISO-NC.