Thermal degradation and hemocompatibility of polyurethane cellulose nanocomposites

Abstract

Bio based polymers are reinforced with natural fibers as a good candidate to the replacement of synthetic materials. In this work biobased polyurethane cellulose nanocomposites (PUCNs) prepared from hydroxylated olive oil and diphenyl methane - 4, 4 - diisocyanate,in the presence of dibutyl tin dilaurate as catalyst and incorporated with varying concentration of cellulose nanocrystals. The polyurethane cellulose nanocomposites films have been characterized by FTIR, XRD, SEM and TGA/DTA studies. The compatibility of the nanocomposites is evaluated by invitro hemolytic assay method. The FTIR analysis indicates the presence of the cellulose nanocrystals in the polyurethane matrix. The formation of urethane linkage is confirmed by the stretching vibrations of the peak around 3330 cm-1. XRD diffraction pattern of the samples shows a increase of 2% crystallinity by the addition of cellulose nanoparticles. The average size of cellulose nanocrystals is calculated as 16nm. SEM images shows a rod like structure of cellulose nanocrystals and the fine dispersion of cellulose nanocrystals in the polymer matrix. The degradation of PUCNs is more pronounced in different chemical environments than polyurethane. Thermogravimetric analysis observed that the addition of cellulose nanocrystals increases the thermal stability of PUCNs upto 300oC.