A novel nanocomposite of rigid polyurethane foam was prepared by the polymerization of a sucrose-based polyol, a glycerol-based polyol and polymeric methylene diphenyl diisocyanate in the presence of cellulose whisker...A novel nanocomposite of rigid polyurethane foam was prepared by the polymerization of a sucrose-based polyol, a glycerol-based polyol and polymeric methylene diphenyl diisocyanate in the presence of cellulose whiskers. The cell morphology of the resulting foams was examined by scanning electron microscopy which showed both the pure foam and the nanocomposite foam had homogeneous cell dispersion and uniform cell size of approximately 200 μm. Analysis of the foams by Fourier transform infrared(FT-IR) spectroscopy indicated that both samples exhibited signals attributed to the polyurethane including the NH stretching and bending vibrations at 3320 cm^(-1) and 1530 cm^(-1), the OC=O vibration at 1730 cm^(-1) and the CO-NH vibration at 1600 cm^(-1). FT-IR analysis of the nanocomposite indicated that cellulose whiskers were crosslinked with the polyurethane matrix as the signal intensity of the OH stretch at 3500 cm^(-1) was significantly reduced in comparison to the spectral data acquired for a control sample prepared from the pure polyurethane foam mixed with cellulose whiskers. According to ASTM standard testing procedures, the tensile modulus, tensile strength and yield strength of the nanocomposite foam were found to be improved by 36.8%, 13.8% and 15.2%, and the compressive modulus and strength were enhanced by 179.9% and 143.4%, respectively. Dynamic mechanical analysis results testified the improvements of mechanical properties and showed a better thermal stability of the nanocomposite foam.展开更多
Nanocelluloses have emerged as novel materials and attracted significant interest from both academia and industry.Nanocelluloses can now be produced at pilot plant and pre-commercial scales,and even at commercial scal...Nanocelluloses have emerged as novel materials and attracted significant interest from both academia and industry.Nanocelluloses can now be produced at pilot plant and pre-commercial scales,and even at commercial scales in some regions in the world.Successful commercial applications of nanocelluloses have entered commercial stages though their full potentials are yet to be developed.In this short communication,the applications of these nanomaterials are high-lighted,including high-volume applications(e.g.,paper,textiles),high-value applications(e.g.,aerogels and structure materials for aerospace),and novel/emerging applications(e.g.,organic light emitting diodes,photonic films).Close collaboration between industries and the academic world would facilitate the development of commercial markets for using nanocelluloses in existing/new areas.展开更多
基金financial support from the PSE Fellowship program at IPST@GT
文摘A novel nanocomposite of rigid polyurethane foam was prepared by the polymerization of a sucrose-based polyol, a glycerol-based polyol and polymeric methylene diphenyl diisocyanate in the presence of cellulose whiskers. The cell morphology of the resulting foams was examined by scanning electron microscopy which showed both the pure foam and the nanocomposite foam had homogeneous cell dispersion and uniform cell size of approximately 200 μm. Analysis of the foams by Fourier transform infrared(FT-IR) spectroscopy indicated that both samples exhibited signals attributed to the polyurethane including the NH stretching and bending vibrations at 3320 cm^(-1) and 1530 cm^(-1), the OC=O vibration at 1730 cm^(-1) and the CO-NH vibration at 1600 cm^(-1). FT-IR analysis of the nanocomposite indicated that cellulose whiskers were crosslinked with the polyurethane matrix as the signal intensity of the OH stretch at 3500 cm^(-1) was significantly reduced in comparison to the spectral data acquired for a control sample prepared from the pure polyurethane foam mixed with cellulose whiskers. According to ASTM standard testing procedures, the tensile modulus, tensile strength and yield strength of the nanocomposite foam were found to be improved by 36.8%, 13.8% and 15.2%, and the compressive modulus and strength were enhanced by 179.9% and 143.4%, respectively. Dynamic mechanical analysis results testified the improvements of mechanical properties and showed a better thermal stability of the nanocomposite foam.
文摘Nanocelluloses have emerged as novel materials and attracted significant interest from both academia and industry.Nanocelluloses can now be produced at pilot plant and pre-commercial scales,and even at commercial scales in some regions in the world.Successful commercial applications of nanocelluloses have entered commercial stages though their full potentials are yet to be developed.In this short communication,the applications of these nanomaterials are high-lighted,including high-volume applications(e.g.,paper,textiles),high-value applications(e.g.,aerogels and structure materials for aerospace),and novel/emerging applications(e.g.,organic light emitting diodes,photonic films).Close collaboration between industries and the academic world would facilitate the development of commercial markets for using nanocelluloses in existing/new areas.
