Super-adsorbent polyacrylate under swelling in water for passive solar control of building envelope

Super-adsorbent polymers have the capacity to immobilize huge quantities of water in the form of hydrogel, thanks to their configuration. A commercial sodium polyacrylate (PA) was analysed as such and at different water uptakes, indicated through the weight ratios PA:H2O. The hydrogels were prepared using different type of water (tap, distilled and deuterated) and characterized by Infrared and Raman spectroscopic analyses, nuclear magnetic resonance experiments, CHN elemental analysis, measurements of thermal conductivity and diffusivity. All the measurements were done in order to assess applications of PA:H2O gels as Thermal Energy Storage systems for improving thermal performances of building envelope through passive solar walls. It has been observed that the behaviour of the hydrogels depends both on temperature and water content. In certain conditions such as low weight ratios, a spontaneous and quick cooling of the hydrogel could be observed. The curves of heat flow and average specific heat (cp) were determined as a function of temperature in order to investigate the states of water in PA hydrogels. When a few water molecules are present, they are mainly and strongly bonded with carboxylate groups. Increasing the amount of water, greater shells of solvation around ionic groups form and water molecules can even interact with neighbouring non-polar hydrocarbon groups. At very high amount of water molecules, they are much more involved into H-bonds among themselves, rather than with PA, so that water pools form into the links of polymeric network. Bulk-like water can freeze and melt. Whatever the amount of water in the hydrogel, its thermal capacity is higher than dry polymer, because the heat can be absorbed by the continuous desorption of water from polymer to bulk-like water (watergel → waterliquid), which can evaporate as temperature approaches 100 °C (watergel → waterliquid → watervapour)

Three-Dimensional (3D) Printed Silver Nanoparticles/Alginate/Nanocrystalline Cellulose Hydrogels: Study of the Antimicrobial and Cytotoxicity Efficacy

Here, a formulation of silver nanoparticles (AgNPs) and two natural polymers such as alginate (ALG) and nanocrystalline cellulose (CNC) was developed for the 3D printing of scaffolds with large surface area, improved mechanical resistance and sustained capabilities to promote antimicrobial and cytotoxic effects. Mechanical resistance, water content, morphological characterization and silver distribution of the scaffolds were provided. As for applications, a comparable antimicrobial potency against S. aureus and P. aeruginosa was demonstrated by in vitro tests as function of the AgNP concentration in the scaffold (Minimal Inhibitory Concentration value: 10 mg/mL). By reusing the 3D system the antimicrobial efficacy was demonstrated over at least three applications. The cytotoxicity effects caused by administration of AgNPs to hepatocellular carcinoma (HepG2) cell culture through ALG and ALG/CNC scaffold were discussed as a function of time and dose. Finally, the liquid chromatography-mass spectrometry (LC-MS) technique was used for targeted analysis of pro-apoptotic initiation and executioner caspases, anti-apoptotic and proliferative proteins and the hepatocyte growth factor, and provided insights about molecular mechanisms involved in cell death induction

Sistemi inorganici e ibridi inorganici-organici per trattamenti conservativi di materiali lapidei e lignei

Inorganic and hybrid inorganic-organic systems for conservative treatments of stone and wood materials The research has focused on the synthesis, characterization and application of inorganic and hybrid inorganic-organic systems for conservative treatments of stone and wood. The wood preservatives synthesized and tested for biocidal activity are polyamidoamines functionalized with hydroxyl and siloxane groups, while the coatings applied on the stones are water based TiO2 nanosols with photocatalytic and self-cleaning properties. Firstly is reported the synthesis of amidoamines by addition reaction between an α,β-unsaturated amide (2-propenamide or N,N'-methylenebisacrylamide) and an amine (ethanolamine or diethanolamine). Their synthesis is a simple system for the study of polyamidoamines. The characterization of the starting reagents and the products of addition was made by means of different techniques (ESI-MS, NMR, FTIR and Raman spectroscopy). The model amidoamines synthesized by aza-Michael addition have allowed the study of the main parameters that influence the reaction It was verified that the reaction proceeds better in water compared to alcohol, and that at 55 °C the reaction takes place relatively quickly (about 4 h). Polyamidoamines under different reaction conditions were then synthesized. The polymers were functionalized with OH groups (PAAOH) and siloxane groups (SiPAA, SiPAAOH). The various polymers were characterized by spectroscopic techniques (ESI-MS, NMR, FTIR, Raman) and with thermal analysis. Polymers were applied on wood samples and their efficacy against fungi and termites has been verified according to UNI EN. The interaction with the substrate, the depth of penetration and the colour changes induced by the treatment were also investigated. The investigations showed that the polymerization reaction for the polymers with hydroxyl side chain is favoured when the amide is completely dissolved in the solvent and added slowly into the solution containing the ethanolamine, in particular when using water or methanol as the solvent. The measurements carried out on the polymers obtained without solvent at 90 °C show that the reaction proceeds up to completeness in less than 3 hours. As regards the polymers functionalized with siloxane, it is noticed that with increasing EtA/APTES ratio the effectiveness of polymerization increases. The DSC has allowed to evaluate the glass transition temperature of the polymers in the range 109 ÷ 120 °C. The hybrid polymers have been incorporated in the lignocellulosic structure of the wood and subjected to heat treatment (103 ± 1 °C for 18h) in order to increase the crosslinking. The high degree of crosslinking (DOC Degree of Condensation) within the wood has been demonstrated by 29Si-NMR spectra. Thanks to electron microscopy SEM it has been possible to verify the successful impregnation of wood specimens with different treatments. The preparations were applied as a protective coating on wood samples (sapwood of Pinus sylvestris) and tested for efficacy against biotic attack, both xilophagous insects and fungi, and resulted effective. After aging tests the polymers with siloxane functionality (SiPAA, SiPAAOH) are effective on wood-decay fungi. Finally, the synthesis and characterization of sol-gel TiO2 based coatings for the photocatalytic self-cleaning of biocalcarenites, are reported. Nanocrystalline titania sols in acid and basic aqueous environments have been prepared by sol-gel, processing titanium isopropoxide with two complexing agents, acetic acid and malonic acid and different peptizers, i.e. acetic acid, nitric acid and triethylamine. To verify the photocatalytic activity, gold nanoparticles have been added to the sol obtained by acetic acid. The effectiveness of the photocatalytic sols was verified by evidence of degradation of dyes, methyl orange (MeO) and methylene blue (MB), under UV-Vis irradiation. In accordance with the rules on cultural heritage, the harmlessness of coating towards the substrate has been investigated. XRD, Raman and TEM measurements on the corresponding titania powders have revealed nanocrystalline particles of anatase (5-6 nm) and of brookite in lesser amount. DLS and ELS-IEP analyses have indicated that preparations with acetic acid, acetic/nitric acids or malonic/triethylamine (basic) gives stable sols. The catalytic photoactivity of the sols under UV irradiation for the degradation of the anionic azo-dye MeO is much faster with acid sols than with the basic one. The cationic MB dye is completely photodegraded only by the basic TiO2 sol, on which the dye is adsorbed with the formation of trimeric species. Coatings at different pH were applied to biocalcarenites typical of southern Italy (Comiso, Modica, Noto and Lecce stones) used in the Baroque period of interest for cultural heritage. Satisfactory results are obtained by photodegradation under UV irradiation of Modica and Comiso stones coated by acid sol. The colour difference before and after the treatments is acceptable. The coatings do not alter the intrinsic properties of Modica and Comiso stones in the capillarity absorption of water, do not prevent the salts crystallization and leave unchanged the stone characteristics. The sol, used alone or with a silica interlayer, is promising for application in limestone protection. On Pietra di Lecce all the acidic sols showed good photocatalytic activity. All the coatings slightly reduce the capillarity water absorption. Colorimetric analyses show that the coatings do not significantly alter the original colour of the stones. The photocatalytic activity for MeO stain degradation is comparable for all the coatings: the addition of gold nanoparticle improves the cleaning in the first minutes, but the purple coloring prevents its use. On Pietra di Noto, both acid and basic titanium coatings do not alter the proprieties of the stone as the color difference measured is very small and capillarity absorption coefficient are comparable for treated and untreated samples. Referring to durability of the stone, the resistance to salt crystallization is generally improved. As concerns the self-cleaning properties, both TiO2 coatings exhibit a good photodegradation activity of methylene blue and methyl orange dyes. Both nanosols are suitable for harmlessness protection of Pietra di Noto, but the basic one exhibits better performances in term of filmogenic properties, colour changes, water absorption, durability enhancement and photocatalytic degradation of organic dyes and then it should be preferred for calcarenite substrates. The results highlight the compatibility of the treatments with respect to the properties of the calcarenite stones, showing no chromatic changes, no alteration of physical properties, an improvement of the resistance to salts crystallization and good photocatalytic activity on both dyes. This study has revealed that the basic sol is particularly suited for the self-cleaning of carbonatic stones, widely employed in ancient and modern architecture, opening perspectives for further applications.Sistemi inorganici e ibridi inorganici-organici per trattamenti conservativi di materiali lapidei e lignei La ricerca si è concentrata sulla sintesi, caratterizzazione e applicazione di sistemi inorganici e ibridi organici-inorganici per la protezione di pietra e legno. Il preservante del legno sintetizzato e di cui si è testata l’attività biocida è una poliammidoammina funzionalizzata con gruppi idrossilici e silossanici, mentre il rivestimento applicato su pietre è un nanosol a base di TiO2 con proprietà fotocatalitiche e autopulenti. Nella prima parte è riportata la sintesi di piccole molecole ammidoamminiche, ottenute dalla reazione di addizione tra un’ammide α,β-insatura (2-propenammide o N, N'-Methylenebisacrylamide) ed una ammina (etanolammina o dietanolammina). Queste molecole sono state sintetizzate in quanto sistema semplice per lo studio delle poliammidoammine. La caratterizzazione dei reagenti di partenza e dei prodotti di addizione è stata effettuata mediante diverse tecniche (ESI-MS, NMR, FTIR e spettroscopia Raman). Dall’analisi delle molecole modello sintetizzate si è verificato che la reazione procede meglio in acqua rispetto all'alcol, e che a 55 ° C la reazione avviene in modo relativamente rapido (circa 4 h). Successivamente sono state sintetizzate le poliammidoammine (PAA) in diverse condizioni di reazione. I polimeri sono stati funzionalizzati con gruppi OH (PAAOH) e gruppi silossanici (SiPAA, SiPAAOH). I vari polimeri sono stati caratterizzati mediante tecniche spettroscopiche (ESI-MS, NMR, FTIR, Raman) e analisi termica. Quindi, le PAA sono state applicate su campioni di legno e la loro efficacia contro funghi e termiti è stata verificata in accordo alle norme UNI EN. Sono state inoltre studiate l'interazione con il substrato, la profondità di penetrazione e le variazioni di colore indotte dal trattamento. Le indagini hanno mostrato che la reazione di polimerizzazione dei polimeri con catena laterale idrossilica è influenzata dal modo di miscelazione dei reagenti: è favorita quando l'ammide è completamente disciolta nel solvente e aggiunta lentamente nella soluzione contenente l'etanolammina, in particolare quando si utilizza acqua o metanolo come solvente. Le prove effettuate sui polimeri ottenuti senza solvente a 90 °C mostrano che la reazione procede fino a completamento in meno di 3 ore. Per quanto riguarda i polimeri funzionalizzati con gruppi silossanici, si nota che con l'aumentare rapporto EtA/APTES aumenta l’efficienza di polimerizzazione. I polimeri ibridi sono stati incorporati nella struttura lignocellulosica del legno e i provini impregnati sottoposti a trattamento termico (103 °C per 18 ore) per aumentare la reticolazione. L'alto grado di reticolazione dentro il legno è stato dimostrato dagli spettri 29Si-NMR. Grazie alla microscopia elettronica è stato possibile verificare il successo dell’impregnazione dei campioni di Pinus sylvestris. I trattamenti testati come biocidi contro insetti xilofagi e funghi sono risultati efficaci. Infine, sono descritte la sintesi e la caratterizzazione di rivestimenti self-cleaning a base di TiO2 per la protezione di materiale lapideo, in particolare di biocalcareniti. Sols di titania nanocristallina sono stati sintetizzati via sol-gel, in ambiente acido e basico da titanio isopropossido, con due agenti complessanti, acido acetico e acido malonico, e differenti peptizzanti: acido acetico, acido nitrico e trietilammina. Per verificare gli effetti sull’attività fotocatalitica, al sol con acido acetico sono state aggiunte nanoparticelle d’oro. L'efficacia fotocatalitica dei sols è stata verificata mediante prove di degradazione di coloranti organici (Blu di Metilene e Metilarancio) sotto irraggiamento UV-Vis. In conformità con le norme sui Beni Culturali, è stata studiata l'innocuità del rivestimento verso il substrato. Analisi XRD, Raman e TEM sulle corrispondenti polveri di titania hanno rivelato particelle nanocristalline di anatasio (5-6 nm) e di brookite in minore quantità. DLS ed ELS-IEP hanno indicato che le preparazioni con acido acetico, acido acetico/nitrico o malonico/trietilammina forniscono sol stabili. L’attività fotocatalitica dei sols sotto irraggiamento UV per la degradazione del colorante anionico Metilarancio è risultata molto più veloce con sol acido che con quello basico. Il colorante cationico Blu di Metilene è completamente foto-degradato solo dalla formulazione basica. I coating sono stati applicati a biocalcareniti tipiche dell’Italia meridionale, utilizzate in epoca barocca e di interesse per i beni culturali (pietra di Comiso, Modica, Noto e Lecce). Sulle pietre di Modica e Comiso, trattate con la formulazione acida, sono stati ottenuti risultati soddisfacenti per quanto riguarda la fotodegradazione dei coloranti. La differenza di colore prima e dopo i trattamenti è accettabile. I rivestimenti non alterano le proprietà intrinseche delle pietre: assorbimento d’acqua per capillarità, fuoriuscita dei sali cristallizzati dai pori e caratteristiche estetiche. Sulla Pietra di Lecce i sols hanno mostrato una buona attività fotocatalitica per la degradazione del colorante; inoltre l'aggiunta di nanoparticelle di oro migliora le prestazioni nei primi minuti, ma la colorazione violacea impedisce il suo uso nell’ambito dei Beni Culturali. I rivestimenti riducono leggermente l'assorbimento d'acqua per capillarità e le analisi colorimetriche mostrano che, ad eccezione del sol con aggiunta di nanoparticelle d’oro, essi non modificano significativamente il colore originale delle pietre. Su Pietra di Noto, entrambi i nanosols acido e basico mostrano buone prestazioni in termini di idrorepellenza e la resistenza alla cristallizzazione dei sali. Inoltre non alterano l’aspetto estetico della pietra. Per quanto riguarda le proprietà autopulenti, entrambi i rivestimenti di TiO2 mostrano una buona attività fotocatalitica per il degrado dei coloranti. Tutti i sol sintetizzati sono risultati efficaci per il foto-degrado di coloranti sulle pietre studiate. Il sol basico è particolarmente adatto come rivestimento self-cleaning per le pietre carbonatiche, ampiamente utilizzate nell'architettura antica e moderna, suggerendo possibilità per ulteriori applicazioni

The 20th Century Wall Paintings in the Chapel of the Fallen in Parma Cathedral (Italy): Scientific Investigations for a Correct Conservation Project

In this work, we present a diagnostic study carried out on 20th century wall paintings in the Chapel of the Fallen of the Great War in the Cathedral of Parma (Italy). The Chapel was painted in the two-year period of 1921–1922 and has been recently restored. The paintings were investigated in order to study the technique used by the painter, Biagio Biagetti (Porto Recanati, 1877–Macerata, 1948) and their state of conservation. A total of twelve micro-fragments of the painting layers were sampled and investigated using different techniques. Raman spectroscopy revealed the large amount of different pigments used for each hue, many of them being synthetic materials. SEM/EDS analysis showed that the mortar was an aerial lime obtained from calcium carbonate mixed with a small amount of clay. Organic materials were identified by FTIR spectroscopy. GC/MS investigations revealed lipid and proteinaceous materials in the examined specimens; the lipid fraction, however, is not attributable to the presence of drying oils. From the determination of the amino acid content, it became apparent that the proteinaceous fraction is due to the combination of egg and animal glue; this allowed us to infer the use of “a secco” techniques, confirming the visual impressions of the restorer. The results obtained have contributed to the definition of the conservation project in its various phases

Preservanti del legno: trattamenti innovativi a base di poliamidoamine e proposta di norma standard per termiti “del legno secco”

Il legno è una risorsa rinnovabile ampiamente usata come materiale strutturale e per una varietà di manufatti, grazie alle proprietà meccaniche particolarmente vantaggiose ed alle caratteristiche estetiche. Tuttavia, a causa della sua natura organica, è soggetto a deterioramento fisico e biologico e in particolare all’attacco di insetti xilofagi come le termiti. È stato sviluppato e brevettato un trattamento innovativo del legno a base di poliamidoamine (PAA) funzionalizzate con silossani, che è stato testato su diversi agenti di biodeterioramento. A livello europeo e italiano, nell’ambito della tecnologia e dei prodotti per la protezione del legno, le norme standard esistenti riguardano test di efficacia e durabilità del legno nei confronti di diversi organismi, come i funghi lignivori, organismi marini perforanti (es. Teredini) e, tra gli insetti, i coleotteri xilofagi (Anobiidae, Lyctidae, Cerambycidae) e le termiti (Dictyoptera: Isoptera). Tuttavia, considerando in particolare le termiti, le uniche norme esistenti (UNI EN117, UNI EN118) riguardano esclusivamente le termiti sotterranee (Rhinotermitidae) come Reticulitermes spp. Le cosiddette termiti “del legno secco” (Kalotermitidae), rappresentate in Europa da Kalotermes flavicollis e Cryptotermes brevis, sempre più frequentemente si annoverano come pericolosi infestanti di manufatti lignei ed elementi strutturali per abitazioni/edifici. Queste termiti sono assai diverse da quelle sotterranee per caratteristiche biologiche ed etologiche, modalità di attacco e tipologia di danno sul legno e non è pertanto proponibile ne accettabile utilizzare le norme esistenti relative alle termiti sotterranee. Per sopperire all’assenza di norme internazionali ufficiali idonee, viene quindi proposto un protocollo specifico per verificare l’efficacia di trattamenti su legno contro specie di Kalotermitidi. Il presente lavoro era volto a testare l'efficacia di tre formulazioni di PAA (denominate A, B, C) come preservanti del legno, utilizzando per la termite sotterranea R. lucifugus lo standard EN 118, e per la termite del legno secco K. flavicollis il protocollo appositamente sviluppato. Dai risultati è emerso che tutte le formulazioni si sono rivelate efficaci come trattamenti preventivi nei confronti di R. lucifugus, facendo registrare un consumo di legno trascurabile ed una mortalità significativamente maggiore rispetto al controllo. Per quanto riguarda K. flavicollis, tutte le formulazioni di PAA hanno comportato una riduzione significativa del livello di attacco del legno e la formulazione B si è rivelata la più efficace anche nel ridurre la sopravvivenza delle termiti. Nel complesso, i trattamenti innovativi a base di PAA appaiono promettenti nella protezione del legno dagli attacchi delle termiti, risultando efficaci a basse concentrazioni, oltre ad avere un ridotto impatto ambientale e a dimostrare un buon fissaggio nel legno. Il protocollo proposto per la norma standard sulle termiti del legno secco si è rivelato valido ed efficace e potrebbe essere candidato tra le norme internazionali a questo scopo

The Polychromatic Inscriptions on the Relief Sculpture <i>Deposition from the Cross</i> by Benedetto Antelami in Parma Cathedral, Italy

This paper reports on the studies carried out on engraved inscriptions of the Deposition from the Cross by Benedetto Antelami (1150–1230), a relief sculpture conserved in the Cathedral of Parma (Italy). The inscriptions between the characters show residues of colored material in alternating red- and dark-colored stripes. The purpose of this specific investigation was to identify the materials (pigments and organic binders) used for the polychromy that are still present on the relief sculpture. Seven microsamples were taken to carry out laboratory analyses. In red-colored letters, mercury, and sulfur, constituents of the cinnabar (or vermilion) pigment were easily identified by SEM-EDS. This result is confirmed by Raman spectroscopy and XRD measurements. In the dark letters, carbon, iron, and lead are observed. The presence of materials containing metals is compatible with a mastic encrustation technique. FT-IR, Raman, and XRD techniques clearly detect beeswax, which was probably used as a polishing material. Amino acids and lipids that are typical of eggs have been identified by means of GC-MS investigations, suggesting their use as organic components of the mastic encrustation

The polychromatic inscriptions on the relief sculpture Deposi-2 tion from the Cross by Benedetto Antelami in Parma Cathedral, 3 Italy

This paper reports on the studies carried out on engraved inscriptions of the Deposition from the Cross by Benedetto Antelami (1150–1230), a relief sculpture conserved in the Cathedral of Parma (Italy). The inscriptions between the characters show residues of colored material in alternating redand dark-colored stripes. The purpose of this specific investigation was to identify the materials (pigments and organic binders) used for the polychromy that are still present on the relief sculpture. Seven microsamples were taken to carry out laboratory analyses. In red-colored letters, mercury, and sulfur, constituents of the cinnabar (or vermilion) pigment were easily identified by SEM-EDS. This result is confirmed by Raman spectroscopy and XRD measurements. In the dark letters, carbon, iron, and lead are observed. The presence of materials containing metals is compatible with a mastic encrustation technique. FT-IR, Raman, and XRD techniques clearly detect beeswax, which was probably used as a polishing material. Amino acids and lipids that are typical of eggs have been identified by means of GC-MS investigations, suggesting their use as organic components of the mastic encrustatio

Green Extraction of Cellulose Nanocrystals of Polymorph II from <i>Cynara scolymus</i> L.: Challenge for a “<i>Zero Waste</i>” Economy

The increase of agri-food wastes by agriculture and industries is one of the main causes of environmental pollution. Here we propose the recycling of Cynara scolymus L. wastes to obtain polymorph II cellulose nanocrystals (CNC). Two different extraction procedures are compared: (i) Soxhlet extraction in an ethanol/toluene mixture, and (ii) water boiling of the agricultural waste. Both procedures were followed by purification of cellulose fibers through bleaching treatments and extraction of cellulose nanocrystals by acid hydrolysis. CNCs have been extensively characterized by FTIR spectroscopy, electrophoretic light scattering measurements, X-ray powder diffraction methods, transmission electron microscopy, and thermogravimetric analyses. Extracted CNC are rod-like-shaped polymorph IIs with a good crystallinity index, and they are characterized by high hydrogen bonding intensity. The ELS measurements on samples from both procedures show good results regarding the stability of the CNC II sol (ζ Cynara scolymus L. waste can be used to produce high-quality cellulose nanocrystals as a green alternative to the commonly used synthetic route