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A multilayer nanofibrous membrane consisting of a layer of polycaprolactone and one of physically cross-linked alginate-embedding ZnO nanoparticles is prepared via electrospinning technique as potential wound healing patches with drug delivery capabilities. A washing-cross-linking protocol is developed to obtain stable materials at the same time removing poly(ethylene oxide), which was used here as a cospinning agent for alginate, without interfering with the membrane's peculiar nanofibrous structure. The mechanical behavior of the samples is assessed via a uniaxial tensile test showing appropriate resistance and manageability together with a good thermal stability as proved via thermogravimetric analysis. The polycaprolactone external layer enriches the samples with good liquid-repellent properties, whereas the alginate layer is able to promote tissue regeneration owing to its capability to promote cell viability and allow exudate removal and gas exchanges. Moreover, using methylene blue and methyl orange as model molecules, promising drug delivery abilities are observed for the mats. Indeed, depending on the nature and on the dye-loading concentration, the release kinetic can be easily tuned to obtain a slow controlled or a fast burst release. Consequently, the proposed alginate-polycaprolactone membrane represents a promising class of innovative, simple, and cost-effective wound healing patches appropriate for large-scale production.

Mark–Houwink parameters are determined for sodium alginate with low (SA LV) and medium (SA MV) molecular mass via a rheological approach. Firstly, salt screening concentration and polyelectrolyte nature of the polymers are investigated. Despite both alginates behaving as neutral polymer in θ solvent, differences are observed between them with the strong associative nature of SA MV highlighted by an abnormal high viscosity concentration dependence compared with the predicted values. The polysaccharide-specific hydrodynamic volume (i.e., intrinsic viscosity) is determined via Fedors approach, which is proved to provide accurate results applicable to a wide concentration range. A viscosity–molecular mass–concentration relationship is finally derived to calculate Mark–Houwink parameters via a non-linear regression according to Kulicke equation; the obtained values are consistent with those reported in literature, confirming the semi-flexible nature of SA in the investigated environment and proving the effectiveness of the proposed approach for polyelectrolytes with added salt ions.

The present review discusses the use of cyclodextrins and their derivatives to prepare electrospun nanofibers with specific features. Cyclodextrins, owing to their unique capability to form inclusion complexes with hydrophobic and volatile molecules, can indeed facilitate the encapsulation of bioactive compounds in electrospun nanofibers allowing fast-dissolving products for food, biomedical, and pharmaceutical purposes, filtering materials for wastewater and air purification, as well as a variety of other technological applications. Additionally, cyclodextrins can improve the processability of naturally occurring biopolymers helping the fabrication of "green" materials with a strong industrial relevance. Hence, this review provides a comprehensive state-of-the-art of different cyclodextrins-based nanofibers including those made of pure cyclodextrins, of polycyclodextrins, and those made of natural biopolymer functionalized with cyclodextrins. To this end, the advantages and disadvantages of such approaches and their possible applications are investigated along with the current limitations in the exploitation of electrospinning at the industrial level.

Poly(vinyl alcohol) nanofibrous mats containing ad hoc synthesized gold nanostructures were prepared via a single-step electrospinning procedure and investigated as a novel composite platform with several potential applications. Specifically, the effect of differently shaped and sized gold nanostructures on the resulting mat physical-chemical properties was investigated. In detail, nearly spherical nanoparticles and nanorods were first synthesized through a chemical reduction of gold precursors in water by using (hexadecyl)trimethylammonium bromide as the stabilizing agent. These nanostructures were then dispersed in poly(vinyl alcohol) aqueous solutions to prepare nanofibrous mats, which were then stabilized via a humble thermal treatment able to enhance their thermal stability and water resistance. Remarkably, the nanostructure type was proven to influence the mesh morphology, with the small spherical nanoparticles and the large nanorods leading to thinner well defined or bigger defect-rich nanofibers, respectively. Finally, the good mechanical properties shown by the prepared composite mats suggest their ease of handleability thereby opening new perspective applications.

Chitosan nanofibrous membranes are prepared via an electrospinning technique and explored as potential wound healing patches. In particular, the effect of a physical or chemical crosslinking treatment on the mat morphological, mechanical, water-related, and biological properties is deeply evaluated. The use of phosphate ions (i.e., physical crosslinking) allows us to obtain smooth and highly homogenous nanofibers with an average size of 190 nm, whereas the use of ethylene glycol diglycidyl ether (i.e., chemical crosslinking) leads to rougher, partially coalesced, and bigger nanofibers with an average dimension of 270 nm. Additionally, the physically crosslinked mats show enhanced mechanical performances, as well as greater water vapour permeability and hydrophilicity, with respect to the chemically crosslinked ones. Above all, cell adhesion and cytotoxicity experiments demonstrate that the use of phosphate ions as crosslinkers significantly improves the capability of chitosan mats to promote cell viability owing to their higher biocompatibility. Moreover, tuneable drug delivery properties are achieved for the physically crosslinked mats by a simple post-processing impregnation methodology, thereby indicating the possibility to enrich the prepared membranes with unique features. The results prove that the proposed approach may lead to the preparation of cheap, biocompatible, and efficient chitosan-based nanofibers for biomedical and pharmaceutical applications.

This paper deals with the interfacial adhesion properties of Ti-6Al-4V alloy substrates, prepared by using different treatment protocols selected on the basis of their different effectiveness, and bonded using a structural, high-strength epoxy adhesive. The alternative pre-bonding treatments were sodium hydroxide anodization and low-pressure-plasma treatment, the effects of which were compared to that of a base preparation via solvent degreasing of the substrates’ surface. The treated surfaces were joined according to standard protocols, and then tested for shear strength. The mechanical results were then correlated to surface characteristics of the substrates such as oxidation state and wettability. Parallel scanning Kelvin-probe measurements allowed us to focus our attention on the possible role of the electrical properties of the substrates. We observed that each treatment entails different behavior of the electrical potential of the surface, which correlates with the mechanical strength of the joints. The results suggest that an evaluation of the surface potential of titanium-alloy substrates might be a promising, indicative supplementary parameter for the evaluation of their pre-bonding surface conditions, allowing correlations with presence/absence of an oxide layer at the resin-substrate interface.

Alginate-based electrospun nanofibers prepared via electrospinning technique represent a class of materials with promising applications in the biomedical and pharmaceutical industries. However, to date, the effect of alginate molecular mass and block composition on the biological response of such systems remains to some extent unclear. As such, in the present work, three alginates (i.e., M.pyr, L.hyp, A.nod) with different molecular features are employed to prepare nanofibers whose ability to promote cell adhesion is explored by using both skin and bone cell lines. Initially, a preliminary investigation of the raw materials is carried out via rheological and zeta-potential measurements to determine the different grade of polyelectrolyte behaviour of the alginate samples. Specifically, both the molecular mass and block composition are found to be important factors affecting the alginate response, with long chains and a predominance of guluronic moieties leading to a marked polyelectrolyte nature (i.e., lower dependence of the solution viscosity upon the polymer concentration). Subsequently, physically crosslinked alginate nanofibrous mats are first morphologically characterized via both scanning electron and atomic force microscopy, which show a homogenous and defect-free structure, and their biological response is then evaluated. Noticeably, fibroblast and keratinocyte cell lines do not show significant differences in terms of cell adhesion on the three mats (i.e., 30-40% and 10-20% with respect to the seeded cells, respectively), with the formers presenting a greater affinity toward the alginate-based nanofibers. Conversely, both the investigated osteoblast cells are characterized by a distinct behaviour depending on the alginate type. Specifically, polysaccharide samples with an evident polyelectrolyte nature are found to better promote cell viability (i.e., cell adhesion in the range 15-36% with respect to seeded cells) compared to the ones displaying a nearly neutral behaviour (i.e., cell adhesion in the range 5-25% with respect to seeded cells). Therefore, the obtained results, despite being preliminary, suggest that the alginate type (i.e., molecular structure properties) may play a topical role in conditioning the efficiency of healing patches for bone reparation, but it has a negligible effect in the case of skin regeneration.

Due to its high toxicity, Pb2+ pollution is a serious threat for human health and environments. However, in situ real-time detection of Pb2+ pollution is difficult and laboratory instruments are usually required. Then, the possibility to monitor water quality without laboratory instruments could lead to the extensive assessment of polluted water sources, especially in rural environments and developing countries where large lead concentrations are often found in surface water. Consequently, new simple colorimetric sensors are highly interesting in the field. In this work we report for the first time disposable polymer planar 1D photonic crystals made of poly (N-vinylcarbazole) as high refractive index medium and sodium alginate as low refractive index and active medium for the detection of Pb2+ in water. The detection relies on the ionic exchange occurring into the alginate matrix. This process effectively induces a physical cross-linking phenomenon, which inhibits water solubilization of the polymer. In turn, this affects the spectral response of the planar 1D photonic crystals modifying its color.

Chitosan-based membranes were prepared via electrospinning technique using a low concentrated acetic acid solution as solvent and poly(ethylene oxide) as co-spinning agent. Different solutions were rheologically characterized and increasing the solution viscosity was found to correspond to a better-defined morphology. The membranes were first subjected to a coagulation process with different baths in order to stabilize chitosan and the mats were found not able to withstand a strongly basic environment. Subsequently, a physical and a chemical crosslinking approach were separately optimized to obtain stable mats whose composition was assessed via thermogravimetric and spectroscopic techniques, proving in both cases the elimination of the co-spinning agent. Above all, the ionically crosslinked mats represent a class of extremely promising biomedical products being probably highly biocompatible and characterized by thin and homogenous nanofibers with a diameter of 200 nm, thus showing the ideal structure to foster cell viability.

The effects of varying percentage loadings of morpholine pre-treated cellulose nanofibrils (MCNF) and carboxymethylated cellulose nanofibrils (CMCNF) on the aqueous swelling, compressive modulus and viscoelastic properties of calcium-ion-crosslinked alginate hydrogels were investigated. In addition, the pore structures of hydrogels with the highest compressive modulus were studied. The incorporation of 5 wt. % MCNF resulted in a slightly reduced aqueous swelling, a 36% increase in compressive modulus and a layered pore structure when compared with the neat alginate hydrogel. On the other hand, the addition of CMCNF at the same loading led to a slightly improved aqueous swelling, an increase in compressive modulus (17%) and high porosity. Further increases in CNF loadings did not result in significant increase in material properties. The alginate/CNF composite materials have potentials to be used in applications where good swelling and mechanical robustness are required.

Collagen filaments derived from the two marine demosponges Ircinia oros and Sarcotragus foetidus were for the first time isolated, biochemically characterised and tested for their potential use in regenerative medicine. SDS-PAGE of isolated filaments revealed a main collagen subunit band of 130 kDa in both of the samples under study. DSC analysis on 2D membranes produced with collagenous sponge filaments showed higher thermal stability than commercial mammalian-derived collagen membranes. Dynamic mechanical and thermal analysis attested that the membranes obtained from filaments of S. foetidus were more resistant and stable at the rising temperature, compared to the ones derived from filaments of I. oros. Moreover, the former has higher stability in saline and in collagenase solutions and evident antioxidant activity. Conversely, their water binding capacity results were lower than that of membranes obtained from I. oros. Adhesion and proliferation tests using L929 fibroblasts and HaCaT keratinocytes resulted in a remarkable biocompatibility of both developed membrane models, and gene expression analysis showed an evident up-regulation of ECM-related genes. Finally, membranes from I. oros significantly increased type I collagen gene expression and its release in the culture medium. The findings here reported strongly suggest the biotechnological potential of these collagenous structures of poriferan origin as scaffolds for wound healing.

In the present work, different sodium alginates were used to prepare nanofibrous mats by means of electrospinning technique. Firstly, a molecular characterization of each sample was carried out: the molecular mass and the composition, i.e. mannuronic/guluronic acid ratio, were determined using the Mark–Houwink–Sakurada relation and FTIR spectroscopy, respectively. Afterwards, the polyelectrolyte nature and the characteristic concentration regimes of each alginate were studied through rheological tests. The results indicated that both the molecular mass and the composition strongly influence the properties of the polymer in solution; in particular, long chains and the predominance of guluronic moiety lead to a marked polyelectrolyte behaviour. Subsequently, in order to obtain a good spinnability, polyethylene oxide and Triton X-100 were added to alginate-based solutions. The resulting solutions were carefully characterized by a rheological point of view; the viscosity, viscoelasticity, thixotropy and thermal stability were investigated and correlated with their capability of being electrospun. Two different set-ups were used for electrospinning: one consisted in a dry collector and the other one in a wet collector (immersed in a collecting solution). The morphology of the membranes was characterized through scanning electron microscopy; moreover, thermogravimetric analysis was performed in order to study the final composition and the thermal degradation. The preliminary results indicated that the membrane obtained using guluronic-rich alginate and the wet-collector system is composed of only sodium alginate and characterized by thin fibres and a high porosity, which could make it suitable for pharmaceutical and biomedical applications.

TiO2 was prepared via sol–gel synthesis, and in order to obtain crystallized anatase in a colloidal suspension, it was subjected to a hydrothermal process in the presence of a minimum amount of nanoparticles, which acted as nucleation seeds. Concurrently, high-pH sol–gel syntheses were performed with the increase in NH3 solutions as a comparison for the samples’ activity. Polydimethylsiloxane was chosen as supporting material for the TiO2 nanoparticles for its high surface area and its stability against catalyst’s photoactivity. They were both processed with the electrospinning technique: It was possible to disperse titania among PDMS fibers and to obtain detachable polymeric membranes with the appearance of white soft sheets. These membranes show antibacterial activity under fluorescent light, and thus, they may be used as a film for several kinds of surfaces. The synthesized samples were controlled and characterized by means of rheological measurements, scanning electron microscopy images together with EDS maps, differential scanning calorimetry analyses, diffuse reflectance spectra for energy gap (Egap) calculations and recycling photocatalytic experiments, while Escherichia Coli inactivation gave evidence of the antibacterial activity.

In this paper, raw hemp fibres were used to reinforce a commercial biopolyester, namely poly(1,4-butylene adipate-co-terephthalate), to achieve eco-composite materials. To promote the adhesion between the polyester matrix and the fibrous reinforcement, chemical modification of fibres surface with coupling agents was accomplished. Usually, the grafting of coupling molecules is carried out involving high amount of solvents. Here, in a general approach of an environmental sustainability, uncut, combed and slightly stretched hemp fibres were treated with a green process based on a novel soft plasma jet device (developed by Nadir Srl). This technique activates the fibres surface and, at the same time, allows the deposition of reactive monomers as coupling agents. Three different monomers were investigated: methyl methacrylate (MMA), (3-aminopropyl)triethoxysilane (APTES) and (3-glycidyloxypropyl)trimethoxysilane. Unmodified and surface-modified fibres were characterized and compared in terms of thermal behaviour and morphological features. Long-fibre eco-composites were then prepared by different compression moulding procedures and characterized by thermal, morphological and dynamic mechanical analysis. Experimental evidences indicated that the cold plasma deposition/grafting treatment was successfully carried out; the composite with the best mechanical performance resulted that obtained by using APTES as coupling agent.

Non-ionic polysaccharides, mainly cellulose ethers, have been extensively studied as thickeners in paint formulation. Their mechanism of interaction with the surrounding system is well known and, due to their easy dissolution properties and availability on the market, they are the most used thickening agents. On the other hand, ionic polysaccharides, having possible interaction with the components of the formulation, are less used. In this work, the role of an anionic polysaccharide, sodium alginate (SA), as a thickener, was investigated in a typical wall paint formulation by evaluating its interaction with the principal components of the formulation: water, binder, pigment and extender. Rheology and FTIR spectroscopy were used to evaluate the occurrence of chemical bonds between the polysaccharide chains and the surrounding system. Contemplating the results, sodium alginate, depending on its molecular weight, M ¯ w , and concentration, turns out to be a suitable thickener for wall paint formulations. In particular, the possibility of building-up a network due to the presence of entanglements, and the interaction with water molecules and extender, demonstrated that the formulation prepared with 0.2 wt. % of a medium M ¯ w alginate was the most promising one. On the other hand, low M ¯ w alginate exhibited a weaker gel structure and only if present at 0.4 wt. % was appropriate concentration for a ready-to-use product.

The molecular mass of two sodium alginates with the same composition but different chain length is reduced via a simple ultrasonic treatment and monitored by rheological measurements. The polymer molecular mass decreases until a lower limiting value of 100 kg/mol is reached, with the degradation occurring via a mid-point-chain kinetic consisting into the breakage of the glycosidic bonds towards the middle of the macromolecules. The evaluation of the concentration regimes (i.e. viscosity dependence upon the polymer concentration) demonstrates that short chains are characterized by higher critical concentrations and lower scaling factors, most likely owing to their poor ability to form entanglements. Nevertheless, the typical behaviour of neutral polymer in θ solvent is observed independently of the alginate molecular mass. The viscosity temperature dependence of the investigated solutions obeys Arrhenius law in a wide temperature range. Additionally, the flow activation energy is observed to follow a linear relationship with the polymer molecular mass with values of 26.2 kJ/mol for the longest chains and 18.2 kJ/mol for the shortest ones. Consequently, ultrasonic treatment is here proved to be extremely efficient to reduce the molecular mass of alginate, thus representing a fast, safe and cost-effective approach to obtain materials with tailored properties.

Different additives based on Na oleate, Na oleate – Ca stearate and Al stearate were used in two different quantities (0.15 %w/w and 0.30 %w/w of the solid amount) to enhance the waterproofing effect of mortars. From capillary water absorption test, Na oleate showed the better performance with a reduction of water absorbed of 86% in comparison with the reference mortar. The microstructure showed the presence of microcavities ranging between 0.01 mm and 0.2 mm, due to air bubbles trapped during the mortar preparation for the surfactant effect of Na oleate. The presence of a higher amount of pores (210 mm3/g vs. 175 mm3/g) was confirmed by the Hg porosimetry. Moreover a reduction of the carbonation rate for the presence of additive was verified.

Agar is a natural polymer commonly used in various fields of application ranging from cosmetics to the food industry. In particular, for over forty years agar gels have been used in the field of conservation of Cultural Heritage where they are considered as one of the main well-performing tools in cleaning procedures. In the present work, the relation between the chemical composition and the mechanical strength of four different agar hydrogels was evaluated by comparing the results obtained via pyrolysis-gas chromatography/mass spectrometry and rheological characterization. Agar composition was studied by means of a pyrolysis-gas chromatography/mass spectrometry approach in order to differentiate the anhydrous, galactose and glucose units. Pristine agar gels, gels after double annealing, and gels with and without chelating agent were studied by means of amplitude, frequency and time sweep rheological tests to evaluate all the preparation approaches commonly used by conservators, also taking into account changes in the transparency via UV–vis spectroscopy. A high percentage of anhydrous units in the polymer backbone was found to provide superior mechanical stiffness to the pristine hydrogels, even if it did not seem to affect their long-term stability. The annealing process significantly improved the rheological response of galactose-rich agar hydrogels being able to promote the establishment of additional crosslinking points, whereas the additive presence showed to improve the hydrogel stiffness owing to a more structured polymer network. Moreover, the progressive reduction of the impurities and/or network defects within the hydrogels occurring due to the annealing process slightly increased the transparency of the hydrogels, which is an important aspect for applications in the conservation of Cultural Heritage.

In the present work alginate-based nanofibrous membranes embedding zinc oxide nanoparticles (ZnO-NPs) were prepared via electrospinning technique. ZnO-NPs were synthesized by means of a "green" sol-gel method by using alginate itself as stabilizing agent and characterized through UV-vis spectroscopy, thermogravimetric and morphological analysis. Formulations containing sodium alginate, poly(ethylene oxide) and ZnO-NPs were rheologically studied to identify the most suitable ones to be electrospun; alginate molecular structure played an important role on the solution spinnability due to the polysaccharide capability to establish electrostatic interactions and hydrogen bonds with ZnO-NPs. An innovative washing-crosslinking protocol was developed to obtain stable products which composition was assessed using Fourier Transform InfraRed spectroscopy and thermogravimetric analysis. Morphological investigation combined with EDX spectroscopy proved the obtained mats were highly porous and composed by thin homogenous nanofibers with a good distribution of the used nanofillers, thus representing potential products for several purposes (e.g. biomedical, pharmaceutical and environmental applications).

Collagen is involved in the formation of complex fibrillar networks, providing the structural integrity of tissues. Its low immunogenicity and mechanical properties make this molecule a biomaterial that is extremely suitable for tissue engineering and regenerative medicine (TERM) strategies in human health issues. Here, for the first time, we performed a thorough screening of four different methods to obtain sponge collagenous fibrillar suspensions (FSs) from C. reniformis demosponge, which were then chemically, physically, and biologically characterized, in terms of protein, collagen, and glycosaminoglycans content, viscous properties, biocompatibility, and antioxidant activity. These four FSs were then tested for their capability to generate crosslinked or not thin sponge collagenous membranes (SCMs) that are suitable for TERM purposes. Two types of FSs, of the four tested, were able to generate SCMs, either from crosslinking or not, and showed good mechanical properties, enzymatic degradation resistance, water binding capacity, antioxidant activity, and biocompatibility on both fibroblast and keratinocyte cell cultures. Finally, our results demonstrate that it is possible to adapt the extraction procedure in order to alternatively improve the mechanical properties or the antioxidant performances of the derived biomaterial, depending on the application requirements, thanks to the versatility of C. reniformis extracellular matrix extracts.

Hyaluronic acid (HA) solutions represent an important class of biomedical products, mostly used in viscosupplementation of joints and as fillers. In the present work the hydrodynamic and rheological properties of hyaluronic acid, of differing MW(90-4000 kDa), in physiological saline were investigated. Firstly, the effective conformation taken by the polymer chains was studied using dynamic light scattering. It was observed that they behaved like random coils which dimension is higher increasing the molecular weight of the material. Secondly, combining a novel microrheological technique, based on the dynamic light scattering of tracer particles, with conventional rheometry, it was possible to study in which way the molecular weight and the concentration of the polymer influence the storage modulus (G’), loss modulus (G”) and complex viscosity (η*) of its solutions, over an extended frequency range (typically 0.01-10000 Hz). This extended characterization allowed determination of the mesh size ξ of the physical network, created by the entangled polymer chains. Calculated mesh sizes in the range 200-700 nm were observed, demonstrating the possibility to use these systems as injectable carriers of biomolecules with an appropriate dimension.

The on-site assessment of the effectiveness and durability of conservation treatments have several drawbacks which have their origin in the demands of the owners (both from the aesthetical point of view and with the need to conclude the restoration as soon as possible), and in the requirements of the restorer related with the logistic of the yard and with the need to satisfy the owner demands. These aspects are often in conflict with the methodological approach used in the scientific framework for evaluate the performance of applied treatments. The aims of this paper is to suggest practical solutions, capable to overcome the previous problems in the assessment of the efficiency of the consolidating and protective treatments applied on the marly limestone ashlars of the Abbey of San Fruttuoso di Capodimonte (Genoa, Italy). The abbey is located at the bottom of a bay few meters from the see, therefore strongly exposed to the action of the marine aerosol and wave erosion. The consolidation and protection of the marly limestone building material was performed by testing several products both inorganic and organic. Preliminary tests were performed on laboratory samples. Afterwards, the same products were applied on selected ashlars of the facade in order to study their performance in a real condition. The products were ethyl silicate, ethyl silicate with polysiloxane, litium silicate, nanosilica, ammonium oxalate, ammonium phosphate, silane/siloxane, fluorelastomers and acrylic polymers and acrylic/siloxane. The study of the effect of the treatments on the stone samples was performed by non-destructive and micro-destructive methods, and an assessment procedure has been proposed.

To verify the effect of hydrogen bonding on the polymer mixing, blends of poly(vinyl methyl ether) (PVME) and poly(methyl methacrylate) (PMMA) with poly(4-hydroxy styrene) (PHS), respectively, have been prepared. The effect of hydrogen bond strength on the enthalpy of mixing, ΔHM, was investigated by microcalorimetric measurements and FTIR spectroscopy. Infrared analysis allowed to measure the amount of hydrogen bonding by a curve fitting procedure in PHS/PMMA blends, looking to the change in the characteristic bands of carbonyl group of PMMA. In the case of PHS/PMVE, the hydroxyl-stretching region has been investigated to have only a qualitative estimation of hydrogen bonding. For both PHS/PMVE and PHS/PMMA systems, the measured exothermic (negative) ΔHM decreases with the increase in the PHS content, indicating that the presence of strong specific intermolecular interactions, such as hydrogen bonding, favours the polymer blending.

To enhance dispersion of silica into styrene-butadiene emulsion copolymer (e-SBR), used in tyres production, two new modifiers, characterized by 3-mercaptopropyltrimethoxysilane grafted onto polybutadiene oligomers of =900 (sb1) and 5000 (sb3), were used. Silica was modified with several degrees of the two new silanes. Thermodynamic surface properties of the modified silicas were estimated by inverse gas chromatography as a function of the grafting degree of sb1 and sb3. e-SBR/silica compounds, with silica pre-modified and in situ modified during the mixing, were prepared and characterized using vulcanization tests, dynamic-mechanical analysis, and morphological observations by TEM. At degree of silylation lower than 10 wt%, the method of pre-modification allows a better dispersion of the silica within the elastomeric matrix and the best results were obtained using sb3. In particular, the lowest Payne effect, similar to that of a sample containing silica modified with bis-triethoxysilylpropyltetrasulfide, usually used in tyre production, was found for the sample containing silica grafted with about 10 wt% of sb3. POLYM. COMPOS., 35:1603-1613, 2014. © 2013 Society of Plastics Engineers.

Porous membranes based on polydimethylsiloxane fibers with titanium dioxide nanoparticles were developed to be used as photocatalysts. PDMS was chosen as a support for the titania because of its high thermal and chemical resistance to the photodegradative effect of the TiO2. Porous membranes are produced via electrospinning using three different apparatus configurations. The photocatalytic activity analysis shows that the best results are obtained dispersing the titanium oxide on the surface of the polymer using an electrospinning configuration which involves the use of two needles. The membranes produced in this way show a good catalytic activity, even though lower than the one observed for the pure TiO2 nanoparticles. This is caused by the low wettability of the membranes and by the surface area of the oxide being hidden from the polymer.

In the paper we present a new approach for obtaining a controlled gelling process of sodium alginate, based on the quantity of bivalent ions rich alginate micro-beads added as crosslinkers. Typically, calcium ions are used in gelation of alginate solutions. In this study we present different gelling systems realized with alginate microspheres, made by electrospinning methodology, enriched with different bivalent ions (Ca2+, Ba2+ and Mg2+). The microspheres were characterized under the point of view of the morphology by OM and as the ions content. Realized gels were characterized in light of the amount of the ions added to the alginate solution, and in light of the different dimensions of the micro-beads, using rheological measurements to assess the variation in the storage modulus (G′), loss modulus (G″) and complex viscosity (η*).

In this work, a study concerning the composition of Italian papers from the seventeenth to the twentieth centuries was carried out using energy dispersive X-ray fluorescence spectrometry (EDXRF), X-ray diffraction (XRD), and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS). The analyzed samples consisted of papers employed for drawing, writing, printing, and absorbance. Observations carried out by SEM magnified the typical paper morphology. EDXRF in combination with XRD and SEM-EDS allowed the determination of calcite, gypsum, kaolin, talc, magnesite, and dolomite, used as fillers in the production of the papers studied herein. The inks present in the handwritten and printed papers, investigated by SEM-EDS and μ-EDXRF, were synthetic, Fe based, and iron gall inks.

In this article, the miscibility of poly(e-caprolactone) (PCL) with poly(styrene-co-acrylonitrile) (SAN) containing 25 wt % of acrylonitrile is studied from both a qualitative and a quantitative point of view. The evidences coming from thermal analysis (differential scanning calorimetry) demonstrate that PCL and SAN are miscible in the whole range of composition. The Flory interaction parameter χ1,2 was calculated by the Patterson approximation and the melting point depression of the crystalline phase in the blends; in both cases, negative values of χ1,2 were found, confirming that the system is miscible. The interaction parameter evaluated within the framework of the mean field theory demonstrates that the miscibility of PCL/SAN blends is due to the repulsive interaction between the styrene and acrylonitrile segments in SAN. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010

Grafting polymerization of acrylic monomers onto cellulose chains possesses a great potential for tailoring the properties of cellulose-based materials. In this article, some results concerning the grafting polymerization of ethyl acrylate/methyl methacrylate (EA/MMA) 75/25 wt % on cotton fabrics are reported. The effectiveness of the grafting process as a method for the mechanical reinforcement of cotton without any modification of its handle is discussed. In addition, SEM observations were carried out to check the morphological modification occurring on cotton after the grafting reaction. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The methodology to create alginate and alginate/hyaluronic acid membranes, which involves wet conditions electrospinning, is presented in this paper. The wet conditions allow simultaneously to work in water solutions avoiding the toxic solvents and to obtain crosslinked alginate. An accurate rheological characterization of all solutions examined is performed. By optimizing the electrospinning parameters, it is possible to obtain alginate membranes with homogeneous nanofibers and a narrow diameter distribution (i.e., around 100 nm) as well as alginate/hyaluronic acid membranes characterized by a network of bimodal distribution of the dimensions, namely nanofibers with a diameter comparable to the ones of the alginate membrane, in which are blocked microfibers with a ribbon like appearance, as observed in the SEM images. In order to facilitate the electrospinning process, poly(ethylene oxide) is added to the solutions and then removed after membranes preparation, as demonstrated by the differential scanning calorimetry results, obtaining membranes made up only biopolymers. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46390.

BACKGROUND: The miscibility of poly(vinyl acetate) (PVAc) with a series of polyacrylates, namely poly(methyl acrylate) (PMA), poly(ethyl acrylate) (PEA) and poly(butyl acrylate) (PBA), with ester chains of varying bulkiness was studied from both qualitative and quantitative points of view. RESULTS: The evidence from thermal (differential scanning calorimetry) and Fourier transform infrared analyses demonstrates that the miscibility of PVAc with the polyacrylates is rapidly reduced on increasing the bulkiness of their ester chains. Miscibility is quantitatively discussed in the framework of the corresponding states theory applying the approximate Patterson form. For this reason the characteristic values of volume, temperature and pressure were preliminarily evaluated both experimentally, through dilatometric measurements, and by calculations. At the same time, calorimetric measurements allowed the evaluation of the enthalpies of mixing of the components. CONCLUSION: The conclusions reached with this approach are that polar interactions are active among the repeat units of the blend components, but the intensities of these forces are progressively reduced by the shielding of the apolar groups of the polyacrylates. The steric hindrance of the hydrocarbon groups shields the interactions of the polar groups of PVAc with the COOR moieties of the acrylates, so that the miscibility progressively decreases from PMA to PEA to PBA. Copyright © 2009 Society of Chemical Industry

Some polyester and polycarbonate-based waterborne polyurethanes (WPU) were characterised by means of several techniques, to correlate the morphology with their structures and properties. The morphological analysis carried out by transmission electron microscopy on thin sections showed that the selected polyurethanes, after purification, exhibit a nanostructured phase separation between hard and soft domains. The presence of hydrogen bonding and the hard/soft ratio were evaluated by FT IR and NMR spectroscopy. Both the thermal and the dynamic mechanical analysis allowed the polymers microstructure to be correlated with the polymer properties; two glass transition temperatures were determined, corresponding to the hard and soft domains respectively.

Grafting polymerisation of acrylic monomers onto cellulose chains represents a useful method of restoration for both artificially and naturally aged paper-based materials. In this paper, some results concerning the grafting polymerisation of ethyl acrylate/methyl methacrylate 75/25 wt.% copolymer onto several paper grades are reported, highlighting how the presence of fillers in the raw materials reduced the grafting yields. The consolidating and protective effects have been investigated by evaluating the mechanical properties and the wetting behaviour of the grafted samples, and comparing them with the original and aged substrates.

In this article, the Lattice Cluster Theory developed by Freed and coworkers is applied to the poly(styrene)/poly(vinyl methylether) system by measuring the enthalpy and the volume variation associated with the mixing of the two homopolymers. It comes out that the chains architectures previously chosen for the two macromolecules based on the phase diagram and of the partition function developed by the theory correctly predicts the sign of both ΔHM and ΔVM. The foreseen trends as function of mixture composition fit the experimental data only for ΔVM; ΔHM is higher than predicted, asymmetrical and independent on the chain lengths of the components. The conclusion is that the theory needs some final touches in order to obtain a better agreement with experiments. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 791–797, 2008

In this research the thermal stability of paper and its components are investigated, in order to evaluate the effect of the artificial weathering treatments, carrying on measurements of thermal gravimetry; also some SEM observations are performed to follow the degradative phenomena. Our work allowed to correlate the level of degradation of the artificially aged paper samples with that of the naturally aged ones. TGA curves of the weathered samples show changes in respect to the starting materials; particularly, the chemical oxidation appears as the most degradative action in respect to the other physical treatments.

We present an overview of the application of some vibrational spectroscopic techniques (Fourier transform infrared (FTIR) and Raman) to industrial archaeology in the field of cultural heritage, particularly centered on the wallpaper industry. Both techniques present a better performance for cost than other set-ups applied to the analysis of multilayer artworks on cellulose supports. To illustrate the applicability of these techniques, we present examples of different decorative wallpapers from the whole nineteenth century and compare the results obtained with other artworks from the same century. Raman spectroscopy was mainly used in pigment determination with the help of FTIR spectroscopy. The study of the binder was better achieved using FTIR spectroscopy, and FTIR could also be used to evaluate semi-quantitatively the degree of the degradation of the cellulose. The wallpaper industry was a very prosperous sector in the nineteenth century that followed the same pattern of the other crafts from the same century, applying the new pigments available in that period. Antique pigments (e.g., minium, red oxides and carbon black) were determined together with new ones, first synthesised during the nineteenth century (e.g., copper-arsenic pigments and ultramarine blue). We observed a transition in the use of the antique pigments to the new ones in the wallpaper items going through the century. The great transformation of the chemical industry was clearly reflected in the evolution of the wallpaper industry during that century.

Nuclear Magnetic Resonance (NMR) can be successfully applied to a wide number of organic, inorganic, and hybrid materials regarding cultural heritage. High-resolution solid-state NMR provides information on the structure of materials, and portable NMR devices allow non-destructive and non-invasive in situ investigation of variably sized objects. This result is possible by combining open magnets and surface radiofrequency coils to generate a sensitive volume external to the sensor and inside the object under investigation. In this paper we focus on the application of NMR to investigate inorganic porous materials such as pottery, plasters, and stones from cultural heritage sites. 27 Al MAS and 3QMAS, and 29 Si MAS high-resolution solid-state NMR along with spectral deconvolution allowed for the investigation of the chemical structure of ancient pottery. Portable unilateral NMR was used to investigate, in a non-invasive and non-destructive way, the porous structure of pottery. The effect of protective-consolidating treatments on plaster was carefully investigated by 1 H NMR depth profiles that allowed for scanning with micrometric resolution of plaster specimens. Changes occurring in the total open porosity after treatments were also evaluated. NMR diffusion measurements provided information on the restricted geometry of the porous structure of two types of biocalcarenite and tuff. A suitable processing of collected data enabled us to define the average pore radius and pores’ interconnection in these materials.

In the preservation of Cultural Heritage items, the use of polymeric materials for the consolidation and protection of artifacts with historical and artistic value is widely accepted, except for cellulose-based materials, since here there are no suitable products and appropriate application techniques. Grafting polymerization of acrylic monomers onto cellulose chains represents an innovative method of restoration for both artificially and naturally aged textiles. In this article, some results concerning the grafting polymerization of ethyl acrylate/ethyl methacrylate 75/25 and ethyl acrylate/methyl methacrylate/trifluoroethyl methacrylate 73/24.5/2.5 polymers onto linen and cotton are reported. The effectiveness of grafting polymerization as a method for textiles conservation is discussed. The consolidating and protective effects were investigated by evaluating the mechanical properties and the wetting behavior of the grafted samples, and comparing them with the original and aged substrates. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 90–99, 2007

Grafting polymerisation of methyl methacrylate and ethyl acrylate onto linen and cotton was carried out in order to reinforce these materials, when they underwent degradation. Take into account this aim, an artificially ageing was performed onto cellulose based textiles by metaperiodate oxidation, in order to obtain degraded model samples. Carbonyl groups were introduced in the cellulose and used as photosensitive agents, allowing the formation of radical sites during the polymerisation reaction, that started by irradiating the substrate by ultraviolet light. In this paper the effectiveness of grafting polymerisation as a method for textile conservation is discussed, starting from the results obtained from several characterisations, as the grafting yields and the grafting efficacy evaluation, the DSC analysis, the FTIR spectroscopy and the SEM observations. Moreover the consolidating and the protective effects were investigated by evaluating the mechanical properties and the wetting behaviour of the grafted samples, and comparing them with the original and aged substrates. The mechanical strength of cellulose based textiles has been improved, as well as the wetting behaviour has been enhanced.

The mechanical and surface properties of chitosan, poly(vinyl pyrrolidone) (PVP) and chitosan/PVP blends before and after UV irradiation have been investigated by mechanical testing (Instron) and by contact angle measurements. Air-dried specimens were submitted to treatment with UV irradiation (wavelength 254 nm) for different time intervals. The changes in mechanical properties, such as breaking strength, percentage elongation and Young's modulus have been investigated. The results have shown that the mechanical properties of the blends were greatly affected by UV irradiation, but the level of the changes of these properties were smaller in the blend than in pure chitosan and strongly dependent on the time of irradiation and the composition of the samples. The contact angle and the surface free energy were altered by UV irradiation, which indicates photooxidation and an increase of polarity. The range of these changes points to greater sensitivity of chitosan to photooxidation in comparison with PVP and chitosan/PVP blends.

New spherically shaped crosslinked IPN hydrogels based on chitosan and poly(vinylpyrrolidone) were prepared. The IPN hydrogels were synthesized in two steps: (1) chitosan (CHT) crosslinked beads were obtained by reaction of chitosan with ethyleneglycol diglycidyl ether (EGDE); (2) absorption of a suitable amount of a solution of vinylpyrrolidone (VP) monomer from the porous CHT beads followed to VP polymerization and crosslinking inside the network. Sequential IPN's at different composition were obtained: they reversibly swell in water at various pH and show sensitive volumetric behaviour.

An oxidative reaction of cellulose with sodium methaperiodate was performed in order to reproduce the natural ageing of textiles. The oxidised groups were transformed into free macroradicals by treatment with UV light. In presence of acrylic monomers in the vapour phase, these reactive sites become the starting point for the graft copolymerisation of methyl methacrylate and ethyl acrylate onto cellulose. Thermal analysis is a convenient, useful and reproducible method for characterising complex organic materials from plants. In this research we have examined the thermal stability of oxidised and grafted flax and cotton using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) analyses, in order to evaluate the effect of the grafting on their thermal behaviour. In presence of acrylic grafted polymer, the thermal stability of the textiles increases.

Polymeric products are largely used for consolidation of stone in the field of cultural heritage. Nevertheless, the main problem of polymeric compounds is related to their macromolecular nature, it being difficult for a polymer to penetrate inside the pores which may have a very small diameter. These considerations are the starting points for in situ polymerization. According to this technique, not the pre-formed polymer, but the monomer is introduced into the stone and it is polymerized in situ in a subsequent step. Frontal polymerization (FP) is a particular technique in which the heat released by the exothermal reaction of monomer to polymer conversion is exploited to promote the formation of a hot traveling front able to propagate and self-sustain the reaction. In the present work, FP is performed inside the pores of the stone and the results lead to the conclusion that the hot front is still active in the presence of an inorganic material which dissipates partially the heat released during the polymerization. In addition some recent applications of FP are discussed in comparison with the traditional polymerization for the in situ consolidation and protection of stones. Copyright © 2005 John Wiley & Sons, Ltd.

The oxidation reactions of cellulose involve the primary and secondary hydroxyl groups of the pyranose ring and result in carbonyl and carboxyl groups. This reaction can be accompanied by opening the pyranose ring. In any cases the glucosidic bond becomes weaker; the formation of carboxyl groups induces a depolymerisation, thus reducing the polymerisation degree and the physical and mechanical strength of the material. The conversion of 1,2-dihydroxyl groups to dialdehyde by periodate oxidation on cellulose based materials as textiles (flax and cotton) and paper with different composition and characteristics, has been studied. To investigate the cellulose behaviour at different level of oxidation, two different solutions of sodium methaperiodate were used: 0.1 and 0.4 M, for different times of treatment. The oxidised samples become “models” to investigate the different levels of degradation in real materials. Thermal analysis is convenient and reproducible, and is a useful method for characterising heterogeneous organic materials from plants. In this research we have examined the assignment of the exothermic transition in DSC analysis of paper, flax and cotton and its components in order to understand their thermal behaviour in more detail and to evaluate the effect of the oxidation treatment on the thermal behaviour. The aim of our work is to correlate the level of degradation of the oxidised samples with the natural ageing of the real cellulose based materials. The results obtained suggest information in the restoration and conservation field of cellulosic materials.

Estimate of sorption of liquid materials inside porous stones is an important parameter in industrial material testing and cultural heritage conservation. In the latter case, a suitable polymer can be used for both consolidation and conservation, it being applied either in the final form or as its parent monomer, which is subsequently allowed to polymerize in situ by the classical method or by frontal polymerization. However, the sorption of such materials through the stone is often difficult because of their viscosity and/or stone porosity. For this reason, the amount of monomer (or polymer) is a parameter of great interest in order to determine the extent of protection reachable by the treatment. In this paper a new methodology based on X-ray tomography is presented. The methodology makes use of a contrast agent added to the monomer that does not interact with its propagation inside the stone and allows to increase the absorption coefficient and so to observe the monomer inside the sample, which is finally frontally polymerized.

The effectiveness of butyl methacrylate/ethyl acrylate-based copolymers as consolidants for stone was investigated. The penetration of polymeric consolidating products is extremely slight because of their macromolecular nature and in situ polymerization of the monomers is suggested as an alternative technique to the use of macromolecular solutions. The efficiencies of three products synthesized in situ and fluorinated by various copolymers were comparatively evaluated in terms of surface properties, water permeability, and consolidation on a selected stone substrate. Moreover, because the environmental stability of such polymeric products is one of the key factors for their extensive application for conservative treatments, the photooxidative stability of reference polymers prepared in vitro was also investigated. © 2004 Wiley Periodicals, Inc.

In this paper, the properties of some polymeric materials used as consolidating and protective products in the restoration field of stone manufactured objects of artistic interest are discussed. The penetration of polymeric consolidating products is very small because of their macromolecular nature, and in situ polymerization of the monomers is suggested as an alternative technique to the use of macromolecular solutions. The effects of plasticizer agents in the reaction system have been investigated, in order to decrease T g and make the products more elastic.