Silvia Patachia

Macro defect free (MDF) cements are polymer-cement composites characterized by high biaxial flexural strength compared to traditional concrete, having as a drawback a low water resistance. Glazing these composite materials with an inorganic enamel containing TiO₂ nano-particles has led to a high water-stable material with advanced photocatalytic properties. Classic glazing by thermal treatment of samples, at 1050 °C, requires energy consumption and long-time performing. The purpose of this paper is to test the use of solar radiation as a source of energy in the glazing process. A vertical axis solar furnace has been used, from PROMES-CNRS Solar Laboratory, Font-Romeu Odeillo, France, and it has been observed that a uniform appearance of the glaze coating has been achieved; it shows high scratch resistance, meaning a good hardness and adhesion to the substrate. The obtained film was also characterized by SEM, EDS and XRD, aiming to evidence the coat morphology, the TiO₂ distribution and its crystallinity alteration, when compared to the samples obtained by classic thermal treatment. The conclusion of the paper is that using solar radiation in the MDF cement glazing process is a promising approach for obtaining multifunctional materials.

This paper presents a possible alternative to traditional cellulose nanofibers functionalization, by treatment of the material at low temperatures (25–35°C) with electron-beam irradiated 1-hexyl-3-methylimidazolium chloride ionic liquid. The treatment promotes decreasing the crystallinity of the cellulose with up to 45% and possible imidazolium moieties grafting to cellulose, as demonstrated from FTIR, XRD, and elemental analysis. The grafting determines water vapors uptake values with 50–70% lower and water vapors uptake rate with 50% lower than those of reference cellulose nanofibers. The grafting determined also improved adhesion of the cellulose nanofibers to HDPE, thus contributing to the obtaining of polymer matrix composites with improved properties.

Cryogels based on poly(vinyl alcohol) [PVA] and three types of bioinsertions such as scleroglucan, cellulose microfibers, and zein, respectively, have been prepared using capacity of PVA to crosslink by repeated freezing–thawing cycles. The effect of the incorporation of biopolymers on the properties of PVA cryogel has been studied by using several techniques such as: scanning electron microscopy, differential scanning calorimetry, and Fourier transform infrared studies. The obtained biobased cryogel membranes were subjected to sorption and to diffusion experiments using Crystal Violet (CV), a dye commonly used in the textile industry and in medicine. Image analysis with CIELAB system was used both to monitor the cryogels loading with CV and to gain insight in the dye state into the gel, in correlation with the bioinsertion type and gels morphology. Dye diffusion but also sorption capacity of the cryogels was found to be closely related to the type of biopolymer. In this article the equilibrium (sorption isotherms) and transport properties (diffusion and permeability coefficients) of CV, in/through physical cross‐linked PVA hydrogel membranes with bioinsertions has been reported. The highest efficiency for the CV removal from aqueous solutions was obtained for the PVA/Scl cryogels. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41838.

In this paper, a novel method for wood surface impregnation with inorganic compounds, such as titanium dioxide, wolfram trioxide, and calcium metasilicate, using an alkylimidazolium ionic liquid as solvent-carrier is presented. The aforementioned compounds are able to diffuse into the wood surface and form an even coating that provides higher dimensional stability in wood as well as higher Brinell hardness as compared to non-impregnated materials. The main advantage of the proposed method of impregnation is the use of an eco-friendly ionic liquid, avoiding volatile organic compounds. In addition, the process saves time and energy, as it is faster and requires considerably lower temperatures (40°C as compared to 100–200°C with conventional processes of impregnation).

The aim of this study is to determine the suitable conditions for poly(vinyl alcohol) [PVA] cryogels ions loading, aiming to obtain both conductive and antimicrobial gels. Five types of ionic liquids [ILs] have been used: 1-butyl-3-methylimidazolium tetrafluoroborate [BMIMBF₄]; 1-ethyl-3-methylimidazolium chloride [EMIMCl]; 1-butyl-3-methyl-imidazolium chloride [BMIMCl]; 1-hexyl-3- methylimidazolium chloride [HMIMCl]; and 1-butyl-3 methylimidazolium tetracloroferrate [BMIMFeCl₄]. The influence of the ILs ions kosmotropicity, of their concentration and of the polymer/ILs ratio, on the gel’s loading process was studied. The kinetic study of these processes shows that they consist of two simultaneous steps and that they are reversible. PVA/[BMIMBF₄], PVA/[EMIMCl], PVA/[BMIMCl], PVA/[HMIMCl], and PVA/[BMIMFeCl₄] interaction-type has been discussed based on FTIR spectra and conductimetric measurements. The repartition constants of the ILs between the contact liquids and PVA cryogel have been determined. Antimicrobial activity of PVA/ILs gels against E. coli is correlated with their loading degree.