The current article addresses a new strategy for the preparation of polylactic acid/cellulose nanocrystal(PLA/CNCs)nanobiocomposite films with improved structural morphology,mechanical and barrier properties for food ...The current article addresses a new strategy for the preparation of polylactic acid/cellulose nanocrystal(PLA/CNCs)nanobiocomposite films with improved structural morphology,mechanical and barrier properties for food packaging applications.The addition of hexadecyltrimethylammonium bromide(CTAB)and sodium lauryl sulfate(SLS)as cationic and anionic surfactants respectively,was found to play a crucial role in preventing re-aggregation of the CNCs during drying and improving the dispersion of CNCs in the PLA.The coated paper was characterized using mechanical tests,water vapor permeability(WVP),X-ray diffraction(XRD),scanning electron microscopy(SEM)and air permeability.The results showed that the paper coated with PLA containing 7.5%CNCs and 0.15%CTAB based on weight of PLA,gives the highest measured paper properties,where an increase in tensile strength(+133%),Young’s modulus(+309%),tear index(+183%),burst(+60.8)and a decrease in air permeability(−92%)was obtained.展开更多
Cross-linked polyethylene(XLPE)and silicone rubber(SiR)samples were subjected to a high-voltage AC stress plane-plane configuration and inclined plane test,respectively.The voltage was applied such that discharge was ...Cross-linked polyethylene(XLPE)and silicone rubber(SiR)samples were subjected to a high-voltage AC stress plane-plane configuration and inclined plane test,respectively.The voltage was applied such that discharge was observed across the surface of the XLPE test sample for several hours and for visible damage to occur on SiR samples also after several hours.Selected stressed samples together with virgin samples from the same manufactured batch were tested using nuclear magnetic resonance(NMR)spectroscopy.Specifically,^(1)H NMR spin-lattice(T_(1))and spin-spin(T_(2))relaxation time measurements were employed to examine potential changes in the chemical bonding of undamaged and damaged XLPE and SiR samples.Preliminary results show that there may be a moderate increase in the T_(1)and T_(2)values of the damaged samples in comparison with the undamaged ones.This raises the possibility that NMR can be a useful additional experimental tool in characterising material degradation.展开更多
文摘The current article addresses a new strategy for the preparation of polylactic acid/cellulose nanocrystal(PLA/CNCs)nanobiocomposite films with improved structural morphology,mechanical and barrier properties for food packaging applications.The addition of hexadecyltrimethylammonium bromide(CTAB)and sodium lauryl sulfate(SLS)as cationic and anionic surfactants respectively,was found to play a crucial role in preventing re-aggregation of the CNCs during drying and improving the dispersion of CNCs in the PLA.The coated paper was characterized using mechanical tests,water vapor permeability(WVP),X-ray diffraction(XRD),scanning electron microscopy(SEM)and air permeability.The results showed that the paper coated with PLA containing 7.5%CNCs and 0.15%CTAB based on weight of PLA,gives the highest measured paper properties,where an increase in tensile strength(+133%),Young’s modulus(+309%),tear index(+183%),burst(+60.8)and a decrease in air permeability(−92%)was obtained.
文摘Cross-linked polyethylene(XLPE)and silicone rubber(SiR)samples were subjected to a high-voltage AC stress plane-plane configuration and inclined plane test,respectively.The voltage was applied such that discharge was observed across the surface of the XLPE test sample for several hours and for visible damage to occur on SiR samples also after several hours.Selected stressed samples together with virgin samples from the same manufactured batch were tested using nuclear magnetic resonance(NMR)spectroscopy.Specifically,^(1)H NMR spin-lattice(T_(1))and spin-spin(T_(2))relaxation time measurements were employed to examine potential changes in the chemical bonding of undamaged and damaged XLPE and SiR samples.Preliminary results show that there may be a moderate increase in the T_(1)and T_(2)values of the damaged samples in comparison with the undamaged ones.This raises the possibility that NMR can be a useful additional experimental tool in characterising material degradation.
