Calcium carbonate mineralization. Part II: effect of poly(ethylene glycol) and block copolymers molecular weight on formation of precipitate

In this study the role of PEG and PEO-PPO-PEO block copolymers molecular weight in precipitation of calcium carbonate was examined. The CaCO3 particles were characterized by FTIR spectroscopy, X-ray, SEM and particle size distribution analysis. In absence and presence of modifiers, mixing of the reagents led to the formation of calcite crystals. The calcium carbonate obtained with poly(ethylene glycol) and block copolymers was characterized by smaller diameter in comparison with the one without modifiers. It was observed that using compounds with different molecular weights has no obvious effect on the form and properties of precipitated calcium carbonate particles

Mechanically strong nanocomposite films based on highly filled carboxymethyl cellulose with graphene oxide

Biopolymer nanocomposite films were prepared by adding exfoliated graphene oxide nanosheets (GOn) into carboxymethyl cellulose (CMC) at low and high GOn loadings (0.4–7 wt %). As firstly evidenced by viscosity of film-forming solutions, microscopic observations and infrared spectroscopy measurements, it was found that the GOn form a three-dimensional network throughout strong interfacial interactions with CMC, confirming that the GOn were well dispersed within the CMC, even at high GOn content, owing to the presence of several multifunctional groups on both phases which ensured the high compatibility between them. The topography of as prepared films was characterized by atomic force microscopy measurements showing that the films have a smooth surface with a very low average roughness for all range of GOn contents. Furthermore, the thermal stability, glass transition temperature, and tensile properties of nanocomposite films were gradually increased with increasing of GOn contents. By adding 7 wt % GOn, 18% increases of thermal stability, 17% of glass transition temperature, 623% of Young's modulus, and 268% of tensile strength were achieved. This work produced structured CMC-based nanocomposite films containing low and high loadings of well-dispersed GOn. The high performances of these films can be expected to have potential in biomaterials or packaging materials applications