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Novel biodegradable polymeric materials based on protein hydrolysate (PH), derived from waste products of the leather industry, and poly(ethylene glycol) diglycidyl ether (PEG) or epoxidized soybean oil (ESO) were obtained and their physico-chemical properties and mechanical behaviour were evaluated. Different processing conditions and the introduction of fillers of natural origin, as saw dust and wood flour, were used to tailor the mechanical properties and the environmental durability of the product. The biodegradable products, which are almost completely manufactured from renewable-based raw materials, look promising for several applications, particularly in agriculture for the additional fertilizing action of PH or in packaging.

The objective of the present study was to synthesize and to characterize Silica/polyethylene glycol (SiO2/PEG) organic-inorganic hybrid materials containing a high polymer amount (60 and 70 wt%) for biomedical applications. Scanning electron microscopy (SEM) showed that the samples are homogeneous on the nanometer scale, confirming that they are nanocomposites. Fourier transform infrared spectroscopy (FT-IR) proved that the materials are class I hybrids because the two phases (SiO2 and PEG) interact by hydrogen bonds. To evaluate the possibility of using them in the biomedical field, the bioactivity and biocompatibility of the synthesized hybrids have been ascertained. The formation of a hydroxyapatite layer was observed on the hybrid surface by SEM/EDX and FTIR after soaking in simulated body fluid (SBF). Moreover, their biocompatibility was assessed by performing WST-8 cytotoxicity assay in vitro.

When bioactive coatings are applied to medical implants by means of sol-gel dip coating technique, the biological proprieties of the implant surface can be modified to match the properties of the surrounding tissues. In this study organo-inorganic nanocomposites materials were synthesized via sol-gel. They consisted of an inorganic zirconium-based and silica-based matrix, in which a biodegradable polymer (the poly-ϵ-caprolactone, PCL) was incorporated in different weight percentages. The synthesized materials, in sol phase, were used to dip-coat a substrate of commercially pure titanium grade 4 (CP Ti gr. 4) in order to improve its biological properties. A microstructural analysis of the obtained films was carried out by scanning electron microscopy (SEM) and attenuated total reflectance (ATR) Fourier transform infrared spectroscopy (FT-IR). Biological proprieties of the coated substrates were investigated by means of in vitro tests.

In the present work, Silica/Polyethylene glycol (PEG) hybrid nanocomposites containing an antioxidant agent, the quercetin, were synthesized via sol-gel to be used as implants with antioxidant properties. Fourier transform infrared (FT-IR) analysis proved that a modification of both polymer and quercetin occurs due to synthesis process. Scanning electron microscope (SEM) showed that the proposed materials were hybrid nanocomposites. The bioactivity was ascertained by soaking the samples in a simulated body fluid (SBF).

The swelling behavior of molten poly(epsilon-caprolactone) in contact with carbon dioxide has been analyzed by using the pendant drop method. At subcritical pressures, the swelling kinetics of the polymer-gas solution follow the typical Fickian diffusion behavior, the volume approaching an equilibrium value after the initial transient. In supercritical conditions, after the first transient, the volume of the solution does not approach an equilibrium value but still, slowly increases. Raman experiments have suggested that this anomalous time-dependent swelling in scCO2 could be due or to slow, secondary diffusion, or to polymer dissolution in scCO2.

The dynamics of assembly of lamellar (clay) nanoparticles in a molten blend of polystyrene (PS) and poly(methyl methacrylate) (PMMA) with drop-matrix morphology are studied combining viscoelastic measurements and morphological analyses. The goal is studying how the preferred polymer-polymer interface alters the melt state dynamics of the filler and the structures resulting from particle self-assembly. The PMMA drops anchor the lamellae, frustrating their peculiar mobility in the polymer melt, at least until saturation of the available polymer-polymer interface. On the other hand, the clay radically affects the blend morphology, inducing irregularly-shaped drops and drop clustering phenomena even in case of partial coverage of the drop surface.

In the present work, two-dimensional systems based on biodegradable polymers such as poly(ε-caprolactone) (PCL), poly(ethylene oxide) (PEO) and polylactic acid (PLA) are fabricated by means of a sustainable approach which consists in inducing phase separation in solutions of such polymers and "green" solvents, namely ethyl lactate (EL) and ethyl acetate (EA). The extraction of the solvent is promoted by a controlled drying process, which is performed in either air or supercritical CO2. The latter can indeed act as both an antisolvent, which favors the deposition of the polymer by forming a mixture with EL and EA, and a plasticizing agent, whose solvation and transport properties may considerably affect the microstructure and crystallinity of the polymer films. The morphological, topographical and crystalline properties of the films are tailored through a judicial selection of the materials and the processing conditions and assessed by means of thermal analyses, polarized optical microscopy, scanning electron microscopy and confocal interferometric microscopy. The results show that the morphological and crystalline properties of the films are strongly dependent on the choice of both the polymer/solvent system and the operating conditions during the drying step. In particular, the morphological, topographical and thermal properties of films prepared starting from highly crystalline polymers, namely PCL and PEO, are greatly affected by the crystallization of the material.

We prepare and characterize multiphase systems in which small amounts of recycled polymer, namely polyethylene terephtalate (PET) ground from waste bottles, are dispersed in a co-continuous blend of high-density polyethylene (HDPE) and polypropylene (PP). Some of such ternary systems are also filled with plate-like clay nanoparticles with different polarities, in order to assess their influence on the morphology and mechanical behaviour of the blends. On the basis of preliminary wettability considerations and inspections by means of scanning electron microscopy (SEM), the PET is found to preferentially locate within the PP phase. Such a positioning is desirable in order to minimize the presence of multiple interfaces, which is one of the major issues in the recycling process of co-mingles plastics. By means of SEM, dynamic-mechanical analysis and tensile tests we show that the addition of a filler with low polarity, which locates at the PET-matrix interface, has relevant implications on the structure and properties of the ternary systems, refining their morphology at the micro-scale and enhancing their high-temperature mechanical behaviour.

The use of natural antioxidants is an attractive way to formulate nanocomposites with extended durability and with potential applications in bio-medical field. In this work, Vitamin E (VE) in the form of α-tocopherol and Quercetin (Q) are physically immobilized on the outer surface of multi-walled carbon nanotubes (CNTs). Afterward, the CNTs-VE and CNTs-Q are used to formulate thermally stable ultra high molecular weight polyethylene based nanocomposites. The obtained results in the study of the thermo-oxidation behavior suggest a beneficial effect of the natural anti-oxidant carbon nanotubes systems. The unexpected excellent thermo-resistance of the nanocomposites seems to be due to a synergistic effect of the natural anti-oxidant and carbon nanotubes, i.e. strong interaction between CNT surface and anti-oxidant molecules. Particularly, these interactions cause the formation of structural defects onto outer CNT surfaces, which, in turn, increase the CNT radical scavenging activity.

Hybrid flexible polyurethane foams (HPU) were synthesized by using a hybrid hydroxilated adduct (HHA) based on renewable resources. In particular the HHA was obtained by dispersing cellulose wastes in colloidal silica at room temperature, pressure and humidity. The colloidal silica was selected for its ability of modifying the cellulose structure, by inducing a certain “destructurization” of the crystalline phase, in order to allow cellulose to react with di-isocyanate for the final synthesis of the polyurethane foam. In fact, cellulose-polysilicate complexes are engaged in the reaction with the isocyanate groups. This study provides evidence of the effects of the colloidal silica on the cellulose structure, namely, a reduction of the microfiber cellulose diameter and the formation of hydrogen bonds between the polysilicate functional groups and the hydroxyl groups of the cellulose, as assessed by IR spectroscopy and solid state NMR. The HHA was added to a conventional polyol in different percentages (between 5 and 20%) to synthesize HPU in presence of catalysts, silicone surfactant and diphenylmethane diisocyanate (MDI). The mixture was expanded in a mold and cured for two hours at room temperature. Thermal analysis, optical microscopy and mechanical tests were performed on the foams. The results highlighted an improvement of thermal stability and a decrease of the cell size with respect neat polyurethane foam. Mechanical tests showed an improvement of the elastic modulus and of the damping properties with increasing HHA amount.

The paper belongs to the high performace engineering materials. In particular, it deals with cementitious materials reinforced by fillers, in this case a recycled multifunctional filler, such as fly ashes coming from thermoelectric industries. It is shown that the combination of filler with very fine particle size and specific chemical properties may lead to new high performance composite materials, which may be very useful for many engineering applications.

The influence of nanosized calcium carbonate on the gelation process, thermal stability and mechanical properties of rigid poly(vinyl chloride) has been studied. The gelation time of rigid PVC/calcium carbonate nanocomposites depends on the percentage and superficial treatment of CaCO3. The results of thermogravimetric analysis underline an improvement of the thermal stability as a function of the surface modifier. Finally, the flexural modulus, the flexural strength as well as the critical stress intensity factor increase with the addition of poly(acrylic acid) (PAA) or poly(butadiene-co- acrilonitrile-co-acrylic acid) (PBAA) coated nanoparticles.

Epoxy nanocomposites with ceramic nanoparticles, i.e. Al2O3, Tio2 and SiO2, were prepared by combined dispersion techniques, namely mechanical mixing and sonication. The influence of fillers addition on thermal, mechanical and dielectric properties have been investigated by means of Differential Scanning Calorimetry (DSC), Dynamic‐mechanical analysis (DMA) and dielectric spectroscopy to measure the dielectric permittivity, tan δ and volume resistivity. Morphological investigations by Scanning Electron Microscopy (SEM) has been also performed.

High performance polymer based‐cements (i.e. cements having a water to cement ratio, w/a, close to 0.1) almost totally free of defect, have been developed in recent years claiming a great interest for their very high tensile strength compared with traditional cements. These materials can be produced utilizing very simple unit operations and further formed in complex shapes with high surface quality. Indeed these materials have the disadvantage of being too much brittle and for this main reason they are rarely utilized in practice. Toughening the Macro Defect Free Cements (MDF) implies the strict control of the structure. The structure is governed by the process‐induced paste modifications. In this paper we show that toughening can be achieved with elastomeric particles having well defined size distribution and physico‐chemical characteristics in relation with both the binder polymer and the cement chemistry.

Since the properties of semicrystalline polymers depend on the morphology, studies on effect of fillers on the composites crystallization are of great interest. In this work, a micrometric talc and a nanoclay are dispersed in a polypropylene matrix and the influence of two different fillers and temperature on the polymer crystallization behavior in quiescent conditions is assessed by means of differential scanning calorimetry (DSC) and rheological characterization through linear viscoelasticity (SAOS) [1]. The DSC tests lead to the half crystallization time, depending on overall crystallization rate (i.e. nucleation and growth) whereas by rheological measurement one can deduce also the induction time, depending only on nucleation [2].