Novel photopolymerizable nanocomposite formulations, able to photopolymerize with a dual curing mechanism (cationic and radical), were developed, characterized and used in the stereolithography (SL) process for the construction of 3D objects with a very simple geometry. The influence of the presence of organically modified montmorillonite (OM) nanoparticles on the reactivity of the photopolymerizable liquid mixtures was firstly analyzed, as function of the amount of nanofiller, by photocalorimetric analysis (p-DSC). The basal distance of OM before and after mixing with the photocurable formulation was characterized by X-ray diffraction. Composites with higher content of OM show an intercalated structure. An exfoliated structure was instead observed in the composites with the lowest OM content, after photocuring in the SL apparatus. These results were also confirmed by the morphological analysis performed by SEM. The glass transition temperature of nanocomposites, photocured by stereolithography, was finally measured by TMA and DSC techniques, confirming that the photocurable formulation loaded with the lowest amount of OM presents improved properties than the unloaded formulation.

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This work is focused on the optimization of an innovative and cheap process for the valorization of the organic fraction of municipal solid waste (OFMSW), through its transformation into an odorless and environmentally compatible material to be employed for building applications or as a thermal and acoustic insulator. The process starts with the grinding of OFMSW, followed by its sterilization in order to obtain a complete removal of the bacterial activity. Afterwards, the incorporation in a catalysed thermosetting matrix is carried out by mixing the OFMSW to a water soluble urea formaldehyde based resin (UF), characterized by a formaldehyde content lower than 1% wt. The OFMSW/UF blends were firstly analysed by the dynamic rheological analyses, as a function of the content of a proper catalyst, that is able to decrease the curing temperature and time. Rheological analyses results allowed the selection of times and temperatures necessary for the polymerization (T = 60 °C, t = 1 h). The effect of the presence of different additives on both the cure process and the mechanical properties of the cured samples was finally analysed, evidencing that the OFMSW/UF composites possess improved mechanical properties in comparison to that of the neat resin.

A novel UV-light-curable nanocomposite material formed of a methacrylic-siloxane resin loaded with 1 wt % oleic acid and 3-(trimethoxysilyl)propyl methacrylate silane (OLEA/MEMO)-coated TiO2 nanorods (NRs) has been manufactured as a potential self-curing structural coating material for protection of monuments and artworks, optical elements, and dental components. OLEA-coated TiO2 NRs, presynthesized by a colloidal chemistry route, have been surface-modified by a treatment with the methacrylic-based silane coupling agent MEMO. The resulting OLEA/MEMO-capped TiO2 NRs have been dispersed in MEMO; that is a monomer precursor of the organic formulation, used as a "common solvent" for transferring the NRs in prepolymer components of the formulation. Differential scanning calorimetry and Fourier transform infrared spectroscopy have allowed investigation of the effects of the incorporation of the OLEA/MEMO-capped TiO2 NRs on reactivity and photopolymerization kinetics of the nanocomposite, demonstrating that the embedded NRs significantly increase curing reactivity of the neat organic formulation both in air and inert atmosphere. Such a result has been explained on the basis of the photoactivity of the nanocrystalline TiO2 which behaves as a free-radical donor photocatalyst in the curing reaction, finally turning out more effective than the commonly used commercial photoinitiator. Namely, the NRs have been found to accelerate the cure rate and increase cross-linking density, promoting multiple covalent bonds between the resin prepolymers and the NR ligand molecules, and, moreover, they limit inhibition effect of oxygen on photopolymerization. The NRs distribute uniformly in the photocurable matrix, as assessed by transmission electron microscopy analysis, and increase glass transition temperature and water contact angle of the nanocomposite with respect to the neat resin.

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In order to guarantee a very high preservation of stone artworks from water actions, an experimental superhydrophobic photopolymerizable organic–inorganic (O‐I) nanostructured hybrid product, namely HEP, has been developed and tested on a calcarenitic stone characteristic of Apulia Region (Italy), i.e., Pietra Leccese (PL). HEP is a “green” product, not containing harmful solvents, and is able to quickly set and harden at room temperature. The first part of the work was devoted to the analysis of the dimension of the silica nanodomains and the suitability of the liquid system produced to be applied on stone surfaces. To this aim, dynamic light scattering and rheological analyses were performed after different times from the preparation of the O‐I system. The hybrid mixture was subsequently applied on a glass substrate and photopolymerized by UV lamp. Several physical properties (glass transition temperature, transparency, scratch, and surface hardness) were, then, measured on the hybrid coating: a substantial improvement of all the surface properties measured was observed. HEP was, finally, applied on PL elements and different analytical techniques (contact angle, colorimetric and water absorption measurements, liquid water, and vapor water transmission) were used to fully characterize the product in terms of hydrophobicity, protective efficacy, water penetration resistance, and transpiring capability. The protective properties of the novel hybrid coating were also compared with those of two commercial water‐repellent products, applied on the same stone substrate, evidencing that the experimental coating is able to equal the performance of high‐quality commercial products. POLYM. COMPOS., 36:1039–1047, 2015. © 2015 Society of Plastics Engineers

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This work represents an innovative study that, for the first time, explores the possibility to use waste flours to produce thermoplastic polymeric bio-films. To the best of our knowledge, this is the first time that waste flours, derived from bakeries, pizzerias or pasta factories, have been proposed for the production of bio-polymers, as a replacement of neat starch. To this aim, durum waste flour derived from a pasta factory, soft waste flour derived from pizzerias and neat maize starch used as control material were firstly analyzed from dimensional, morphological and chemical points of view. Afterwards, waste flour films were produced by the addition of a nature-based plasticizer, glycerol. Mechanical characterization of the plasticized thermoplastic films, produced by compression molding, evidenced low performances, even in the case of the neat maize starch. In order to improve the mechanical properties, the possibility to include polylactic acid and cardanol-based plasticizer was also investigated. Mass transport properties of all the produced bio-films were investigated by measuring their water vapor permeability and hygroscopic absorption. The durability properties of the bio-films were assessed by accelerated ageing tests, while the bio-degradability of the waste-based films was evaluated by measuring the solubility and the degradation in water. The physicochemical analyses of the novel bio-films evidenced good mechanical properties; specifically, the waste-based films showed a lower hygroscopic absorption and water solubility than those of the blends containing neat starch.