This work is aimed to present an innovative technology for the reinforcement of beams for urban furniture, produced by in-mold extrusion of plastics from solid urban waste. This material, which is usually referred to as “recycled plastic lumber”, is characterized by very poor mechanical properties, which results in high deflections under flexural loads, particularly under creep conditions. The Prowaste project, founded by the EACI (European Agency for Competitiveness and Innovation) in the framework of the Eco-Innovation measure, was finalized to develop an innovative technology for selective reinforcement of recycled plastic lumber. Selective reinforcement was carried out by the addition of pultruded glass rods in specific positions with respect to the cross section of the beam, which allowed optimizing the reinforcing efficiency. The reinforcement of the plastic lumber beams with pultruded rods was tested at industrial scale plant, at Solteco SL (Alfaro, Spain). The beams obtained, characterized by low cost and weight, were commercialized by the Spanish company. The present paper presents the most relevant results of the Prowaste project. Initially, an evaluation of the different materials candidates for the reinforcement of recycled plastic lumber is presented. Plastic lumber beams produced in the industrial plant were characterized in terms of flexural properties. The results obtained are interpreted by means of beam theory, which allows for extrapolation of the characteristic features of beams produced by different reinforcing elements. Finally, a theoretical comparison with other approaches which can be used for the reinforcement of plastic lumber is presented, highlighting that, among others, the Prowaste concept maximizes the stiffening efficiency, allowing to significantly reduce the weight of the components.

Crosslinking and denaturation were two variables that deeply affected the performance of collagen-based scaffolds designed for tissue regeneration. If crosslinking enhances the mechanical properties and the enzymatic resistance of collagen, while masking or reducing the available cell binding sites, denaturation has very opposite effects, as it impairs the mechanical and the enzymatic stability of collagen, but increases the number of exposed cell adhesive domains. The quantification of both crosslinking and denaturation was thus fundamental to the design of collagen-based scaffolds for selected applications. The aim of this work was to investigate the extents of crosslinking and denaturation of collagen-based films upon dehydrothermal (DHT) treatment, that is, one of the most commonly employed methods for zero-length crosslinking that shows the unique ability to induce partial denaturation. Swelling measurements, differential scanning calorimetry, Fourier transform infrared spectroscopy, colorimetric assays for the quantification of primary amines, and mechanical tests were performed to analyze the effect of the DHT temperature on crosslinking and denaturation. In particular, chemically effective and elastically effective crosslink densities were evaluated. Both crosslinking and denaturation were found to increase with the DHT temperature, although according to different trends. The results also showed that DHT treatments performed at temperatures up to 120°C maintained the extent of denaturation under 25%. Coupling a mild DHT treatment with further crosslinking may thus be very useful not only to modulate the crosslink density, but also to induce a limited amount of denaturation, which shows potential to partially compensate the loss of cell binding sites caused by crosslinking. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 186-194, 2016.

Waterlogged wood samples of Ulmus sp. and Fraxinus sp. from the ancient harbor of Otranto in Southern Italy were radiocarbon dated by accelerator mass spectrometry (AMS) and examined for physical and chemical changes to assess the degree of degradation. The analyzed woods were dated to the 2nd half of the twelfth – 1st half of the thirteenth centuries AD. The results of all the used methods (maximum water content, basic density, shrinkage, XRD analysis and holocellulose content) indicated a low level of degradation in the inner part of the wooden find. The outer and middle part, on the other hand, showed a greater degradation level. An important result is the identification of a not homogeneous degradation in the different parts of the examined wooden block, which will affect the design of the consolidating treatment

Abstract: In materials research, the development of polymer nanocomposites (PN) is rapidly emerging as a multidisciplinary research field with results that could broaden the applications of polymers to many different industries. PN are polymer matrices (thermoplastics, thermosets or elastomers) that have been reinforced with small quantities of nano-sized particles, preferably characterized by high aspect ratios, such as layered silicates and carbon nanotubes. Thermal analysis (TA) is a useful tool to investigate a wide variety of properties of polymers and it can be also applied to PN in order to gain further insight into their structure. This review illustrates the versatile applications of TA methods in the emerging field of polymer nanomaterial research, presenting some examples of applications of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA) and thermal mechanical analysis (TMA) for the characterization of nanocomposite materials.

Experimental organic–inorganic hybrid systems, based on silane functionalized difunctional and trifunctional epoxy resins and an alkoxysilane precursor mixture, containing small amounts of ammonium molybdate, are evaluated for potential use as adhesives cured at ambient temperatures. The precursor resin mixtures are found to exhibit a large increase in viscosity with a pseudoplastic behavior. Scanning electron microscopy (SEM) analysis shows the existence of siloxane domains with nanometric dimensions, except for the presence of microscopic molybdate particles. By monitoring the evolution of the glass transition temperature (Tg) during curing, varying the thickness of the specimens between 0.2 and 4.5 mm, it is found that the organic–inorganic hybrids display a significant increase in the final Tg over the parent unmodified epoxy resins, particularly in thin specimens and when ammonium molybdate is added. Small-angle X-ray scattering (SAXS) spectra show that the dimensions and typographic features of thick and thin specimens are similar, both containing an agglomeration of primary particles of 5-6 nm.

Many aspects of concrete have been researched and published over the last few years. Many books have covered the properties, applications and more recently about the durability of concrete. Eco-efficient concrete will look at many different types of concrete and the environmental performance of each type whilst using the latest research on this subject. The first part of the book analyses concretes based on new chemistry cements (sulfoaluminate and magnesia cements) associated to low CO2 emissions. The second part the moves on to analysing concretes that have been partially replaced with Portland cement and discusses pozzolanic activity or hydraulic properties. This chapter describes the use of different polymers, added in fresh or hardened hydraulic cement or to replace the cement. The introduction of polymers, in or with concrete, is able to modify its characteristics and properties, to protect or to repair concrete elements.

Reactive compounds in thermosetting matrices of composite materials are monomers or oligomers characterized by a functionality that ranges from a minimum of two up to six or more, in order to produce a crosslinked network. The generic term of resin is usually referred either to the monomer present in the larger amount either to the mix containing the main monomer and all other reactive components, i.e. curing agents, catalysts and initiators. The same base monomer can thus be used to produce crosslinked polymers characterized by properties strongly different depending on the curing agents. In this section, the curing agents involved in and strictly necessary to the curing reactions, are only considered. In very basic terms, curing agents are divided in two classes depending on the role they play in the curing reactions. In step reactions curing agents participate to form the crosslinked network being present in a significant amount and are often referred as hardeners. In radical chain reactions the initiator, producing the first radical promoting the initiation step, is present in a very limited amount in the reactive mixture (a few percent by weight). The discussion will be essentially limited to epoxy resin and partly to polyester and vinylester resins.

The use of fiber reinforced polymer (FRP) composites for the rehabilitation of buildings or other infrastructure is increasingly becoming an effective and popular solution, being able to overcome some of the drawbacks experienced with traditional interventions and/or traditional materials. The knowledge of long-term performance and of durability behavior of FRP, in terms of their degradation/aging causes and mechanisms taking place in common as well as in harsh environmental conditions, still represents a critical issue for a safe and advantageous implementation of such advanced materials. The research of new and better performing materials in such fields is somewhat limited by practical and economical constrains and, as a matter of fact, is confined to an academic argument.

The success of Fiber Reinforced Polymer (FRP) composites for the strengthening/reparation of concrete structures is due to a favorable combination of suitable properties, superior than those of traditional materials, and manufacture/ installation capability. Of great importance is the behavior of the repaired structure under loading and its durability in the outside climate. The lack of fundamental knowledge on their longterm behavior and of specific standards for durability investigation makes difficult the assessment of reliable theoretical models, hampering their extensive use in construction. The analysis of durability of FRP’s, in terms of their degradation causes and mechanisms, is a critical issue for their safe implementation in concrete structures.

Dehydrothermal (DHT) crosslinking is routinely performed to increase the stiffness and the enzymatic resistance of collagen-based devices. Amide and ester bonds are formed among the collagen macromolecules, as a result of the high temperatures and high vacuum involved in the process. The extent of crosslinking is known to increase with the DHT temperature and duration, but simultaneous collagen denaturation might be induced. The aim of this work was to investigate the extent of crosslinking and denaturation of DHT-treated collagen-based films, by means of thermal and physicochemical analyses. With the ultimate goal of optimizing the DHT process, five different temperatures (110, 120, 140, 160 and 180°C) were used, while the DHT duration was kept constant (24 hours). Differential scanning calorimetry (DSC) was carried out to measure the denaturation temperature (Td) and enthalpy (ΔHd) of the collagen films. The reaction of 2,4,6-trinitrobenzenesulfonic acid (TNBS) with primary amines (-NH2) allowed determining the number of free -NH2 in the collagen films, whereas Fourier transform infrared spectroscopy (FTIR) was used to investigate the chemical modifications occurring upon DHT treatment. Higher degrees of crosslinking were attained for increasing DHT temperatures, as demonstrated by reduced number of free -NH2, lower absorbance of amide II band (1545 cm-1) and higher Td values. However, the sharp reduction of ΔHd detected for samples treated at 140, 160 and 180°C indicated a significant denaturation associated to crosslinking. The analysis of the absorbance band at 1236 cm-1 confirmed that collagen denaturation was particularly pronounced for DHT temperatures higher than 120°C, suggesting that, at those temperatures, denaturation might predominate over crosslinking. Further stress relaxation tensile tests and dynamic mechanical analysis (DMA) are currently being performed to measure the stiffness of DHT-treated samples and to estimate the elastically effective crosslink density, according to the rubber elasticity theory.

The influence of chemical treatments based on novel organic products on the consolidation of deteriorated wood by insect attack was evaluated on two hardwoods and one softwood: fir (Abies alba), beech (Fagus sylvatica) and deciduous oak (Quercus sp.). Degraded and intact specimens of the three wood species were impregnated with two different chemical treatments aimed to verify the potential synergic action of the novel products on wood. Then, the specimens were subjected to bending, compression parallel to the grain, impact, hardness and water absorption tests. Untreated specimens of the same botanical species, both degraded and non-degraded, were examined for comparison purposes. The experimental results showed a different effectiveness of the proposed chemical treatments to improve the mechanical and absorption properties of degraded wood. The most effective treatment was the one assuming the concurrent use of the studied novel consolidants. The species more susceptible of the enhancement in mechanical properties were fir and beech. The observed differentiations were most likely caused by the different structure of the botanical species considered, leading to a consequent different product penetration in the wood structure. The dimensional stability in terms of water repellent and antiswelling efficiency, after a three-month immersion in deionized water, was found to improve in all the treated wood specimens. Overall, experimental results showed that the impact of the chemical treatments was higher on degraded samples than on intact ones.

The effects of exposure to different humid environments in a commercial cold-cured epoxy adhesive were investigated. Samples were exposed up to one month to 55%, 75% and 100% relative humidity (RH) or immersed in liquid water, at a constant temperature (23 C). Weight changes, thermal and mechanical properties before and at different stages of the aging, were discussed. In the examined aging conditions, absorbed water remained below 1% and saturation level was not achieved. Plasticization, reactivation of curing reactions and erasure of physical aging were observed in the specimens subjected to the different humidity regimes, all affecting both the thermal and the mechanical properties of the aged samples: while the Tg was influenced by plasticization mainly at shorter times of exposure and by post-curing at longer treatment times, the mechanical characteristics were less affected by these phenomena. These effects were found more pronounced at humidity levels higher than 75% RH. Doubly hydrogen-bonded water molecules linked to the network also influenced the Tg of the system, while they did not affect noticeably their flexural properties. Finally, the effects of water exposure can be regarded as equivalent to those of a thermal treatment at temperature around the Tg, i.e. both leading to an erasure of the physical aging.

The article investigates the effects of long term environmental aging on thermal and mechanical properties of epoxy-silica hybrids. These nanostructured materials, prepared by non-aqueous sol-gel process and in situ generation of nanosilica during epoxy curing at room temperature, present the potential to be used as cold-cured adhesives for civil engineering and Cultural Heritage applications. A specifically developed conditioning procedure for these cold-cured nanostructured materials was applied before moisture/ water absorption tests. The work evidenced the superior durability of the studied epoxy-silica hybrid, which kept its performances in severe, but realistic, environmental conditions with respect to traditional epoxy adhesives. The reduction in the glass transition temperature and mechanical properties of the studied epoxy-silica hybrid, observed in the first weeks of environmental aging, was followed by a significant recovery. This was attributed to two concomitant phenomena: the reactivation of the incomplete curing reactions in the epoxy domains and the continuation of the condensation reactions in the siloxane domains activated by the absorbed water. Finally, the Fickian behavior, presented by the studied epoxy-silica hybrid, was used as an indirect indication of the homogeneity of achieved microstructure, with well dispersed silica nanostructures in the epoxy network

An epoxy–silica hybrid was produced from a mixture of an amine-silane functionalized bisphenol-A resin and a siloxane precursor derived from tetraethoxysilane with small amounts of glycidoxypropyltrimethoxysilane coupling agent. The low temperature curing characteristics and final properties of the hybrid system were compared to those of two epoxy controls. Examinations were carried out by differential scanning calorimetry, dynamic mechanical analysis, electron microscopy, thermogravimetric analysis, UV–Vis spectroscopy, SAXS and densitometry. The modulus, strength and ductility were measured in 3-point bending mode at 23 and 50 C. The siloxane hybridization of the original epoxy resin was found to increase the glass transition temperature (Tg) of cold cured systems by more than 10 C and to produce large improvements in mechanical properties. The study has also provided new insights for the events taking place during gelation, vitrification and curing to the equilibrium state.

An experimental study was carried out for the development and characterization of innovative photopolymerizable siloxane-modified acrylic formulations for possible use as protective coatings of stone substrates. The kinetics of the radical photopolymerization mechanism induced by UV radiations in presence of a suitable photoinitiator was studied by a calorimetric analysis by varying the atmosphere (oxygen or nitrogen) and the composition of the mixtures, in particular of the UV photoinitiator. The reactivity, expressed in terms of both heat developed and rate of reaction, was generally found to decrease when the photopolymerization was carried out in air, due the inhibiting action of the oxygen towards the free radical polymerization. The addition of a proper thiol to the acrylic modified resin was found to reduce the adverse effect of oxygen on the kinetic reaction and on the degree of conversion. This result allowed to reduce the content of the photoinitiator and to increase the content of the siloxane in the acrylic based mixtures. The effect of the change of the composition of the formulations on the kinetic behaviour of the acrylic based resins was also analysed by calorimetric analysis. Calorimetric experimental data were fitted to a simple kinetic model for radical photopolymerization reactions. Finally, a proper relationship between the glass transition temperature and the total extent of reaction was applied to the experimental data. A good agreement between the experimental data and both the theoretical models was generally found.

The research aims to investigate the effects of natural and accelerated weathering on polyethylene-based films. At this regard, monolayer films of low density/linear low density polyethylene blends, containing commercially available organic pigments and an UV absorber of the benzophenone type, have been considered. The samples were weathered on field (natural weathering) or using two different artificial procedures: UV lamp and QUV chamber. Conditioned film samples were, then, analyzed by performing several physical tests taking as-received films as a reference. Rheological measurements showed an increase in viscosity of weathered sample melts as a consequence of photodegradation phenomena, inducing the formation of double bonds and crosslinks. This latter result was also confirmed by gel content measurements. UV-visible spectroscopic tests indicated that in both cases of natural and artificial weathering an increase of the transmittance of films occurred. Tensile tests indicated the increase of films stiffness, especially in case of samples conditioned using the UV lamp, and a large decrease of the strain at break, both in machine and in transverse directions, especially for film weathered using the QUV chamber.

A study was made of the effects of calcarenitic stone particles, known as pietra gentile, inclusions on the rheological behavior of photopolymerizable siloxanemodified acrylic formulations, intended as protective for the calcarenitic stone structures. Different amounts of stone particles (ranging from 15% wt to 35% wt) were added to the modified acrylic mixture to achieve a natural color matching for calcarenitic stone substrates. The presence of stone particles was expected to modify the rheological behavior of the protective formulation. Therefore, the viscosity of the mixtures was studied at ambient temperature as function of the shear rate and the solid volume fraction. A relationship was obtained to predict the modification of viscosity of each formulation as a consequence of inclusions of different amounts of stone.

In this paper the effect of a long term immersion in water on bond durability is analyzed when FRPs (Fiber Reinforced Plastic) are externally applied to a masonry substrate. In the performed research a substrate made by natural calcareous stones, strengthened by CFRP (Carbon Fiber Reinforced Plastic) sheets has been analyzed. For a better comprehension of water effect on the adhesive bond between stone and CFRP, the same treatments were performed to the constituent materials, namely epoxy resins, CFRP sheets and stones. To this aim mechanical tests were carried out on stone, composite materials and epoxy resins before and after their immersion in water, evaluating the effects of this agent on the properties of the materials. The influence of the aging in water on the interface stone-reinforcement was analyzed in terms of bond strength, maximum bond stress, optimal bond length, slip-bond stress relationship and mode of failure. In addition the possibility of calibrating design relationships, taking into account the influence of environmental conditions is discussed. Detailed results on adhesives and composites aged in water have been reported in a previous paper while in the present work the significant decay of the mechanical properties of the stone is specifically investigated. With regard to the conditioning treatment a reduction of the bond strength has been observed (up to 26%) as well as a similar decrease of the maximum bond stress; in addition the aged specimens have shown a more fragile behavior. On the basis of the obtained results the empirical coefficient, reported in the available Italian Guidelines, to determine the FRPmasonry bond strength seems still effective when the system FRP-masonry is aged in water once the properties of the aged materials are considered in the provided relationships.

An experimental study was carried out for the development and characterization of innovative photopolymerizable siloxane-modified acrylic formulations for possible use as protective coatings. The kinetics of the radical photopolymerization mechanism induced by UV and visible radiations in presence of suitable photoinitiators was studied by a calorimetric analysis by varying the testing conditions (temperature, light power emission, atmosphere). The reactivity, expressed in terms of both heat developed and rate of reaction, was generally found to decrease when the photopolymerization was carried out in air, due the inhibiting action of the oxygen towards the free radical polymerization. The addition of both a silane coupling agent or a high molecular weight polysiloxane monomer to the acrylic resin was found to reduce the heat of reaction. Experimental data were fitted to a kinetic model to quantify the effects of light intensity and temperature on reaction rates and extent of reaction. A good agreement between the experimental data and the theoretical model was generally found.

A deep study on the possibility to increase the quality of the dispersion of organically modified Boehmite nanoparticles into photo-polymerizable methacrylic-siloxane monomers, to be used as coatings, was conducted using unconventional indirect analyses. The nanocomposite were produced using two different procedures, starting from the conventional ‘‘solvent dispersion method.’’ The two procedures used differ for the technique used to obtain the dispersion of Boehmite, i.e., sonication or magnetic stirring and for the time used in each procedure. The efficiency of each method of preparation of nanostructured systems was analyzed, both in the liquid (uncured) and ultraviolet (UV) cured state. First, dynamic light scattering and rheological measurements were performed on the liquid suspensions, supplying experimental data used in proper theoretical models to estimate the dimensions and distribution of Boehmite particles. The suspensions obtained with the two different methods were, then, UV cured obtaining thin and thick films, on which scanning electron microscopy and transmittance measurements were performed.

An innovative photopolymerizable microgel modified UV-cured acrylic-silica hybrid formulation was developed and characterized for possible use as protective coating for different substrates. A deep investigation, aiming at providing a strong scientific basis for the production of organic-inorganic (O-I) hybrids exhibiting phase co-continuity, was firstly carried out. The O-I hybrid first proposed in this study was obtained from organic precursors with a high siloxane content, which are mixed with tetraethoxysilane (TEOS) in such a way to produce co-continuous silica nanodomains dispersed within the crosslinked organic phase, as a result of the sol-gel process. The first part of the research deals with the selection and optimization of suitable systems through appropriate chemical modifications, in order to ensure that curing reactions can be carried out at room temperature and in the presence of UV radiation. Firstly, the silica domains are formed, followed by crosslinking reactions of the acrylic groups in the oligomer via a free radical polymerization. The crosslinking reaction was controlled with the use of a suitable photoinitiator. Most of the experimental work was devoted to understanding the morphology of the hybrid system, both in uncured and cured states, and to assess its final thermal and optical properties, using different experiential techniques.

The work is addressed to investigating the potentiality of calcination of organic-inorganic (O-I) hybrids as a feasible approach to produce silica particles, at mild temperature conditions and with tailored morphology. Two different innovative hybrid systems were obtained through sol-gel process with a siloxane content ranging from 6 to 26wt%. The two O-I hybrids differed for i) the organic matrix (methacrylic or epoxy), ii) its crosslinking mechanism (photopolymerization for methacrylic systems or thermal cold-cure for epoxy systems) and iii) the rate ratio between solgel and crosslinking reactions. Different characterization techniques were used to understand the effect of composition and curing method on the morphology of the silica obtained from O-I hybrids after calcination in air. The results confirm the morphology and properties of silica particles in terms of surface and porosity may be tailored over a wide range by varying the composition and nature of organic and inorganic precursors of hybrids

Three cold-cured epoxy resins, specifically designed as structural adhesives for rehabilitation or renewal applications of civil infrastructures and cultural heritage, were submitted to natural and artificial weathering. We evaluated the variations in the thermal and mechanical properties and color changes after an artificial treatment carried out at 70°C and 75% relative humidity and after natural weathering, performed in two areas of South Italy, both located adjacent to the Mediterranean Sea. The variations in properties due to both natural exposure and artificial weathering were qualitatively similar. However, the selected artificial weathering procedure appeared excessively severe compared to the weathering that occurred after outdoor exposure.

The effects of environmental aging at various levels of humidity were studied on the experimental formulations of epoxy-silica hybrids, specifically designed for curing at ambient temperature to be employed as adhesives for concrete and/or masonry structures. The addition of small amounts of ammonium molybdate to the amine hardener was investigated using thick section specimens (4.5 mm thick) capable of retaining substantial amounts of ethanol either originally added to the resin mixture or subsequently formed by the sol-gel hydrolysis and condensation reactions. The changes taking place during aging were evaluated in terms of variations in glass transition temperature (Tg), water absorption and mechanical properties. It has been found that during environmental aging in moist atmosphere the siloxane domains of the epoxy-silica hybrids undergo additional sol-gel reactions, which bring about a further increase in Tg and substantial increases in Young’s modulus (Eflex) and flexural strength (σmax flex). The observed effects were found to be enhanced by the addition of small amounts of ammonium molybdate to the formulation. Furthermore, the moisture in the atmosphere was found to assist the extraction of the residual ethanol in the specimens.

Novel epoxy-silica hybrid systems based on silane-functionalized epoxy resins containing interpenetrating silica domains were investigated as structural adhesives with the aim to achieve a good retention of properties when the adhesives are exposed to severe environmental conditions or weathered. Durability experiments have been conducted on the experimental hybrid adhesives by monitoring their mechanical properties, on both cast specimens and on adhesive joints composed of cylindrical concrete or masonry blocks, in ordinary conditions or after exposure to different environmental agents (moderate temperature, immersion in water, outdoor exposure).

The application of hydrophobic polymers to stone materials is an effective way to preserve stone artifacts and protect Cultural Heritage from decay. To improve the characteristics and performance of waterrepellent treatments, and to avoid the use of harmful solvents, new solutions have been recently explored. The authors have recently proposed experimental photopolymerizable hybrid organic–inorganic (O–I) protective coatings, mainly intended for the surface protection of porous stones. In this paper, different analytical techniques (contact angle, colorimetric measurements, water absorption measurements, ESEM–EDS analyses) were employed to fully characterize the innovative water-repellent coatings applied on a calcareous stone substrate, typical of Apulia Region (Pietra Leccese, PL). The research work consists of two parts: the first one concerns the evaluation of the appropriate amount of the novel photopolymerizable O–I hybrid coating applied on Lecesse Stone in order to achieve better protective properties; the second one refers to the comparison of the properties of this latter coating with two commercial waterrepellent products. The final performances of the innovative free-solvent photopolymerizable coating, in terms of hydrophobicity and color change, are found to be comparable to those of the commercial products.

In the last years there has been a considerable interest in a new class of materials, known as organic–inorganic (O-I) hybrids, which present unique characteristics arising from the combination of organic and inorganic components. Recently, epoxy-based O-I hybrids, consisting of epoxy resins with interpenetrating silica domains, have been optimized by the authors. The methodology for their production is based on the sol-gel technology, involving the hydrolysis and condensation of metal alkoxides in aqueous solution, which is able to bind chemically, at nanometric scale, the organic phase with the inorganic one. These novel hybrid systems present superior properties then those of the parent resins. The presence of nanostructured co-continuous organic and inorganic domains, in fact, allows to achieve higher glass transition temperatures, greater mechanical properties and enhanced adhesion to different substrates than those experienced by epoxy resins. Thanks to their peculiarities, these epoxy-based hybrid systems have been investigated by the authors as potential “cold-cured” adhesives, i.e. to be cured at ambient temperature and to be used in Cultural Heritage for restoration of artefacts and consolidation of masonry structures. The main interest in cold-cured epoxy-silica hybrids lies, in fact, in the possibility of overcoming the main limitations of conventional cold-cured epoxy resins, currently used as adhesives and matrices for FRP (Fiber Reinforced Plastics) in the restoration and repair of ancient masonry structures. They require, in fact, long curing times, while, due to the incomplete cure, the glass transition temperature (Tg) of the final products can only achieve values about 10-20°C higher than the temperature used for the curing process. Moreover, the Tg of cold-cured epoxies can decrease to even lower values through the absorption of water, due to plasticization phenomena caused by strong association of OH of water with NH groups of the epoxy. The aim of this chapter is to analyse the properties of the organic–inorganic epoxy-based hybrid systems, highlighting their potential as efficient, structural and non-structural, adhesives for Cultural Heritage.

An attempt to substitute in concrete the 5% by weight of fine aggregate (natural sand) with an equal weight of PET aggregates manufactured from the waste un-washed PET bottles (WPET), is presented. The WPET particles possessed a granulometry similar to that of the substituted sand. Specimens with different cement content and water/cement ratio were manufactured. Rheological characterization on fresh concrete and mechanical tests at the ages of 28 and 365 days were performed on the WPET/concretes as well as on reference concretes containing only natural fine aggregate in order to investigate the influence of the substitution of WPET to the fine aggregate in concrete. It was found that the WPET concretes display similar workability characteristics, compressive strength and splitting tensile strength slightly lower that the reference concrete and a moderately higher ductility.

Several innovative photopolymerizable siloxane-modified acrylic formulations were characterized, both in presence or absence of organically Boehmite (OMB) nanoparticles, in order to assess their rheological and kinetic behavior. The experimental formulations were mainly intended for the surface protection of porous stones or wood elements. The importance of the experimental investigation lies in the specific requirements necessary for the proposed applications, i.e. the innovative UV coatings developed should possess adequate viscosity, photopolymerization reaction rate and time. The kinetics of the radical photopolymerization mechanism, induced by UV radiations, was studied by calorimetric analysis and FTIR spectroscopy as function of the mixtures composition and test conditions (air or nitrogen atmosphere). The addition of a silane coupling agent or a high molecular weight polysiloxane monomer to the acrylic resin was found to reduce the heat of reaction. On the other hand, the presence of Boehmite nanoparticles in the UV photopolymerizable formulations does not seem to modify the reactivity of the siloxane-modified acrylic formulations. The effect of the presence of oxygen on the kinetic reaction was also investigated and correlated to the composition of the systems. Finally, the viscosity of the formulations was studied at ambient temperature with a parallel plates rheomether as a function of composition and shear rate. The viscosity curves were also fitted according to theoretical models as function of shear rate and composition, obtaining a good agreement between experimental data and model predictions.

This work was aimed to test the suitability of an epoxidized cardanol derived plasticizer for the production of soft PVC characterized by low environmental and toxicological impact soft PVC. Nowadays, the use of natural derived plasticizer in soft PVC industry is emerging as valid alternative towards conventional phthalate plasticizers, in order to reduce the environmental and toxicological impact of soft PVC. In facts, cardanol is a natural and renewable resource, characterized by a wide worldwide availability. In addition, being derived from cashew nut shell liquid, which is a by-product of cashew nut shell industry, it does not contribute to the subtraction of resources from the food chain, in contrast, for example, to epoxidized soybean oil. To this purpose, soft PVC samples were produced in an industrial plant, using both cardanol derived and phthalate plasticizer. Thermal and mechanical characterization showed that the properties of PVC plasticized by cardanol derivative are comparable to those of soft PVC obtained by phthalate, which is a clear indication of the good plasticizing effectiveness of cardanol derivative, and highlights its potential for the production of soft PVC characterized by reduced environmental and toxicological impact.

Novel UV-photopolymerizable siloxane-modified methacrylate/ Boehmite nanocomposites were experimented as possible protective coatings for different substrates. To this aim, unfilled and Boehmite-filled suspensions were applied and photocured on a glass substrate. A subsequent detailed experimental characterization was performed in order to evaluate the effect of the presence of Boehmite nanoparticles on the surface properties of the coatings and on their durability characteristics. In particular, transparency, glass transition temperature, scratch, and surface hardness, contact angle, and color change were measured on the coatings applied on glass support before and after QUV accelerated weathering cycles.

Novel nanocomposite UV - cured coatings, based on photopolymerizable siloxane-modified acrylic formulations with the addition of organo-modified Boehmite (OMB), are proposed as potential protective coatings for porous stones and wood elements. The OMB nanofiller has been dispersed into an optimized acrylic-based formulation in the presence of a proper photoinitiator for UV-curing. This represents the first example of the use of Boehmite-based UV-cured nanocomposite in the field of Cultural Heritage. The advantages offered by UV-cured coatings with respect to traditional heat-cured ones mainly reside in the attainment of superior performance achievable in less time. The use of a nanocomposite protective coating will guarantee better surface properties and durability characteristics. In this chapter, the characterization of the innovative liquid photopolymerizable siloxane-modified acrylic formulations, both in presence or absence of OMB nanoparticles, is presented in order to assess the suitability of the proposed products for the specific applications. A wide experimental characterization of the solid coatings, applied on different substrate and photo-cured by using a medium pressure Hg UV lamp, is illustrated, in order to assess the attainment of the expected superior properties in terms of transparency, hydrophobicity, surface resistance, glass transition temperature, among the most important. An accelerated weathering procedure is proposed as a means to evaluate the weathering resistance of the coatings.

An organo-modified Boehmite (OMB) was used to prepare nanocomposite UV-cured coatings, based on an innovative photopolymerizable siloxane-modified acrylic formulation, for possible use as protective coatings. 3 wt.% of the nanofiller was dispersed into the mixture in the presence of a proper photoinitiator for UV curing. Different amounts of a silane coupling agent were added to the mixture in order to enhance the compatibility between the nanofiller and the siloxane-modified acrylic formulation. The kinetics of the radical photopolymerization reaction, induced by UV radiations, was studied by photo-calorimetric analysis. The rheological behaviour of the formulations produced was studied as function of the shear rate using a plate and plate rheometer. The formulations, coated on a glass substrate, were photo-cured by using a medium pressure Hg UV lamp. On the coatings photo-polymerized in air were measured: gel content, transparency, scratch and surface hardness. The water absorption effect of the coating based on the novel organic photo-curable nanocomposite on walnut wood elements was evaluated.

tThe kinetic behavior of innovative photopolymerizable UV-cured methacrylic–silica hybrid formula-tions, previously developed, was studied and compared to that of a reference control system. Theorganic–inorganic (O–I) hybrids proposed in this study are obtained from organic precursors with a highsiloxane content mixed with tetraethoxysilane (TEOS) in such a way to produce co-continuous silicanano-domains dispersed within a cross-linked organic phase, as a result of the hydrolysis and condensa-tion reactions. The kinetics of the radical photopolymerization mechanism induced by UV-radiations, inpresence of a suitable photoinitiator, was studied by calorimetric, FTIR and Raman spectroscopic analy-ses, by varying the composition of the mixtures and the atmosphere for reactions. The well known effectof oxygen on the kinetic mechanism of the free radical photopolymerization of the methacrylic–siloxanebased monomers was found to be strongly reduced in the hybrid system, especially when a properthiol was used. The experimental calorimetric data were fitted using a simple kinetic model for radicalphotopolymerization reactions, obtaining a good agreement between the experimental data and the the-oretical model. From the comparison of the kinetic constants calculated for control and hybrid systems,it was possible to assess the effect of the composition, as well as of the atmosphere used during thephoto-polymerization process, on the kinetic of photopolymerization reaction.

An experimental study was carried out for the development and characterization of novel photopolymerizable siloxane-modified methacrylic formulations containing hydroxyapatite (HA) powders for possible use as protective coating for carbonate stone substrates. The experimental formulations were mainly intended for the surface protection of porous stones, in particular those employed in Apuliam monumental, archeological and historical constructions, or wood supports. Amounts of HA particles ranging from 2.5 wt.% to 20 wt.% were added to a siloxane-modified methacrylic mixture, previously investigated. The effect of inclusion of HA particles in the methacrylic mixture on the final properties of the photopolymerizable systems, applied on glass support and on two different carbonate stone elements, was investigated. To this aim, the transparency and scratch hardness characteristics of the coatings, photo-cured on a glass substrate, were firstly measured. Then, the hydrophobic properties and

An experimental study was carried out for the development and characterization of innovative photopolymerizable siloxane-modified acrylic formulations for possible use as protective coatings for stone substrates. Two amounts of calcarenitic stone particles (25 wt.% and 35 wt.%) were added to a siloxane-modified acrylic mixture. The effect of stone particles inclusion on the reactivity and surface properties of the photopolymerizable systems was investigated. To this aim, the kinetics of the radical photo-polymerization reaction, induced by UV radiations in the presence of a suitable photoinitiator, was studied by calorimetric analysis, both in air and nitrogen atmosphere. The formulations, coated on a glass substrate, were photo-cured by using a medium pressure Hg UV lamp in air. On the coatings photo-polymerized in air were measured: gel content, transparency, scratch and surface hardness.

The assessment of durability of fiber-reinforced polymers (FRP), used to strengthen masonry or concrete structures, if subjected to weathering is a knotty problem. Environmental factors can have a significant effect on their performance in service. In order to investigate on this aspect, the mechanical behavior of two commercial composites, reinforced with unidirectional carbon and glass fibers, respectively, was analyzed after a long term immersion in distilled water. For comparison purposes, three different commercial epoxy resins, used as primer, putty or adhesive to manufacture and apply the composites through the wet lay-up technique to the surfaces to strengthen, were subjected to the same treatment. In order to take into account the peculiarities of the three cold-curing epoxy resins, a novel procedure to dry the specimens before the immersion treatment was used. The mechanical tests, performed on the composites before and after their immersion in water, evidenced that this agent has a limited effect only on the in-plane tensile strength of wet lay-up manufactured GFRP, while the mechanical properties of CFRP are substantially unaffected by water. On the other hand, the effect of water on the thermal and mechanical characteristics of the three epoxy resins is quite severe, with significant reductions in the glass transition temperature, stiffness and strength.

Organic-inorganic hybrids made of an organic phase based on epoxy oligomer and an inorganic phase consisting of silica nanodomains wherein the organic phase based on epoxy oligomer is polymerizable at room temperature and the silica nanodomains are produced in situ thanks to a modified sol-gel process carried out in the absence of organic or aqueous solvents and their use as adhesives or matrices for composite materials used in the rehabilitation, repair, consolidation and restoration of infrastructure and cultural heritage as well as in related methods, are disclosed.

A nanostructured organic-inorganic hybrid formulation comprising an organic phase based on methacrylic-silane monomers, which is crosslinkable by solar radiations, and an inorganic phase, obtained from an alkoxy-silane precursor, is described. The inorganic phase is composed of continuous silica nanodomains, obtained after hydrolysis and condensation reactions, dispersed within the crosslinked organic phase. The nanostructured organic-inorganic hybrid formulation is crosslinkable by solar radiation and comprises 4-15% by weight of at least one alkoxy-silane compound, 22-90% by weight of trimethoxypropyl silane methacrylate and functionalized poly(dimethylsiloxane)-terminated vinyl, 5-60% by weight of a methacrylic resin and 1-5% by weight of a photoinitiator mixture containing at least one UV photoinitiator and at least one photoinitiator that can be activated by visible light

A nanostructured organic-inorganic hybrid formulation comprising an organic phase based on methacrylic-silane monomers, which is cross-linkable by UV radiation, and an inorganic phase, obtained from an alkoxy-silane precursor, is described. The inorganic phase is composed of continuous silica nanodomains, obtained after hydrolysis and condensation reactions, dispersed within the cross-linked organic phase. The nanostructured organic-inorganic hybrid formulation is cross-linkable by UV radiation and comprises 4-15% by weight of at least one alkoxy-silane compound, 22-90% by weight of methacrylic-silane monomers whereof at least one is functionalized, 5-60% by weight of a methacrylic resin and 1-3% by weight of a UV photoinitiator and 1-4% by weight of an organic solvent.