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The increasing demand for the use of sustainable materials in industrial applications has created an urge to develop technologies that enable the use of biopolymers such as cellulose for the improvement of properties of commercial products. In this study, the potential of the silyl functionalized cellulose nanofibrils (CNF) as a reinforcing additive for the water- and solvent-based two-component polyurethane (PU) lacquer coatings was evaluated. The addition of the silylated CNF improved the abrasion resistance, strength, and elasticity of the PU coatings. When using the silylated CNF as an additive, the adhesion of the PU coatings was retained. The oxygen permeation rate of the silylated CNF films was strongly influenced by the nature of the solvent. The silylated CNF showed potential as a reinforcing additive even at low loadings in the two-component PU lacquers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 133, 44801.

Recently, surface treatment concepts with slow release encapsulated activates have shown to provide a potential approach for the control of biological surface contamination. These new protection concepts respond to the current regulations and demands set for the sustainable development. In this study, screening of the efficacy of biocidal agents – benzoic acid and sodium benzoate – embedded in poly(acrylic acid) matrices was carried out. The efficacy of the polymer systems on mould growth was tested with the blue stain fungus Aureobasidium pullulans and with the mould fungi Trichoderma harzianum and Aspergillus niger. In addition, release of the active agents at different pH was determined in aqueous media. The release tests in aqueous media showed that the release of the active agents is more pronounced at pH higher than 4. The efficacy of the polymer systems according to the present arrangements was dependent on the fungi and the release rate of the active agents from the matrix.

Two organic–inorganic hybrid sol–gel coatings were developed in order to modify the surface energy and moisture behaviour of the commercial impregnated paper. The surface characteristics of the paper samples were studied by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectroscopy (ToF-SIMS). It was found that the applied sol–gel coatings as well as the curing process changed the surface structural and chemical properties of the impregnated paper. The chemical bonding between the hydroxyl groups present on paper surface and silanol groups from sol–gel coatings was confirmed by the FTIR spectra. The measured surface energies divided into polar and dispersive components indicated that the coating B resulted in less polar surface than did the coating A which was more polar than the reference (the impregnated paper with water and heat treatment). Coating B brought about the lowest total surface energy. It was obtained that the water repellence of the impregnated paper was improved by both coatings and the curing process.

Two hybrid coatings synthesized by using alkoxysilanes as precursors in a sol–gel process, differing from each other in terms of the organic components in alkoxysilanes, have been developed to improve the water repellent properties of base paper. The sol–gel-coated base paper samples were characterized by scanning electron microscopy, atomic force microscopy, confocal laser scanning microscopy, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and contact angle measurements. The sol–gel coatings were found to clearly change the surface properties of base paper. Thin coating layers were formed on base paper surfaces. The topographical data indicated the formation of discontinuous thin films; the time-of-flight secondary ion mass spectrometry analyses confirmed that the coatings were covering the fibres but only partially covered the fibre–fibre intersections. Water and the subsequent heat treatment used as a reference treatment reduced the surface roughness and porosity and slightly changed the surface chemistry of the base paper. The wettability and absorptivity of base paper was clearly reduced by the applied coatings. Copyright © 2011 John Wiley & Sons, Ltd.

The surface morphology and moisture behaviour of pine (Pinus sylvestris) sapwood and heat-treated spruce (Picea abies) deposited with two types of silane-based sol–gel coatings were studied by atomic force microscopy (AFM) and water contact angle measurement. The chemical composition and distribution of sol–gel coatings on wood surfaces were investigated by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The AFM images revealed that the sol–gel coatings applied by spreading covered the fine structure of the wood substrates. The surface roughness analysis of the AFM topographical images indicated that the sol–gel coatings, especially the one with short aliphatic chain, had a tendency to smooth the wood surface. The XPS results confirmed that the sol–gel coatings had successfully deposited onto pine sapwood and heat-treated spruce changing their surface chemistries. ToF-SIMS images showing Si ion distribution on treated surfaces revealed that the coatings fully covered pine sapwood surfaces. The thin coating layers formed on heat-treated spruce surfaces followed the original wood surface structure. The contact angle measurements indicated that the water repellent properties of both pine and heat-treated spruce were improved to certain extent by the sol–gel coatings.

Self-emulsifying binders have been prepared by reaction of long oil alkyd resins with maleated derivatives of fatty acids. These binders were dispersed in water without use of external surfactants and free from volatile organic compounds. The binders were evaluated based on their performance properties, including penetration and moisture repellency ability against commercial references. According this study, binders with interesting properties have been prepared. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Two silane-based hybrid coatings were developed to modify the surface energy of phenolic resin impregnated paper. The coated paper samples were further pressed onto surfaces of plywood. The surface properties and water repellence of coated paper were investigated by AFM, XPS and water contact angle measurements. The water absorption of plywood with pressed paper was studied by water uptake tests. It was found that the sol-gel coatings had slightly improved the water repellence of the impregnated paper. The water absorption of plywood was also slightly decreased.

Preparation and properties of alkyd–acrylic hybrids have been studied. Hybrids with different alkyd–acrylic ratios and acrylic parts were prepared via free radical polymerization of acrylic monomers in a presence of an unsaturated alkyd resin using emulsion polymerization technique. The binders were characterized according to their solid content, conversion, viscosity, pH and particle size. Evidence on formation of true copolymer was obtained via NMR spectroscopy and molecular weight and glass transition temperature measurements, as well as via performance studies. The performance evaluation was focused on investigation of drying, penetration and water repellency ability, as well as on film formation and surface topography studies. The binders were compared to references of an alkyd emulsion, acrylic latex and a blend made of them. The results showed that alkyd–acrylic hybrids with synergistic and improved properties can be prepared.

Scots pine planks were heat‐treated under steam in a temperature range of 100–240°C at every 20°C. Changes in chemical structure of the wood samples were examined with UV resonance Raman (UVRR) and Fourier transform infrared (FT‐IR) spectroscopies. Prior to the FT‐IR and UVRR analysis, the heartwood part of wood samples were ground and extracted with acetone. Both the extracts and the extracted samples were analyzed. In addition, Klason lignin contents of the samples were determined. The FT‐IR and UVRR spectroscopy were powerful techniques to monitor chemical changes in the heat‐treated wood samples. Results confirmed most of what determined previously by other research groups using different techniques. The UVRR and FT‐IR spectra of acetone extracts showed that lignin became partly acetone soluble after a heat treatment of 180°C or greater. Increased levels of free phenolic hydroxyl groups were detected in lignin, probably due to cleavages of β‐O‐aryl ether interunit linkages. The amount of extr...

Scots pine samples, heat-treated (225°C under steam) and reference (kiln-dried), were exposed to natural weathering for 7 years in Espoo, Finland. The weathered and unweathered samples were examined with FTIR, UV resonance Raman, and 13C CPMAS NMR spectroscopies. The spectroscopic results revealed that the lignin contents of the weathered heat-treated and especially of the weathered reference softwood samples diminished significantly. The surface of the weathered heat-treated sample was still rich in aromatic and conjugated carbonyl structures, whereas the surface of the reference sample was enriched with cellulose. These results indicated that weathering products of lignin were leached out with water from the reference sample, whereas in the heat-treated wood they were largely unleachable. The structure of the heat-treated wood was modified and degradation products did not leach out as easily as in the case of the reference sample. The weathering also resulted in a decreased content of amorphous polysaccharides of the reference sample, whereas the changes in the polysaccharide contents between weathered and unweathered heat-treated samples were not as dramatic because the amorphous carbohydrates were already degraded in the heat treatment. The results indicated that heat-treated wood is more resistant to natural weathering than untreated wood. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2128–2134, 2004

Scots pine battens were heat-treated at 100–240º C under saturated steam. Cross-sections of heat-treated battens were analysed using ATR and reflection FTIR microscopies. A typical absorption band of fats and waxes at 1740 cm-1 was detected on the sapwood edges in the temperature range of 100–160º C, indicating that fats and waxes moved along the axial parenchyma cells to the surface of the sapwood during the heat treatment. At the elevated temperatures (above 180° C) fats and waxes disappeared from the sapwood surface and were no longer detected with FTIR spectroscopy. Resin acids were detected at temperatures between 100 and 180º C in the middle of the battens. IR spectra of these spots showed a characteristic absorption band of resin acids at 1697 cm-1. At 200º C resin acids were not detected in the middle of the battens; however, resin acids were detected at distances of 500 and 600 mm from the midpoint of the battens and on the edges of battens. At temperatures above 200° C, resin acids had disappeared from the wood.

Summary Thermal modification is a technique to produce wood with increased dimensional stability and lower equilibrium moisture content. 2H NMR relaxation measurements and pulsed field gradient (PFG-NMR) methods are non-invasive spectroscopic techniques that can be used to measure the response of liquid confined in porous materials and yield information on the size and distribution of the pores. These methods were used to study the structure and changes in structure of thermally modified Scots pine wood. The 2H longitudinal relaxation measurements of wood samples at different moisture contents showed different relaxation times and relaxation time distribution in the thermally treated samples. The effect of the thermal treatments on the cell size in wood samples was studied by PFG-NMR measurements with different dwell times. The PFG-NMR measurements showed no clear change in the cell dimensions of the thermally modified samples compared with control samples taken from the same log.

Polystyrene (PS, 1), polycaprolactone homopolymers (PCL, 2) and 3-Iodo-2-propynyl n-butylcarbamate (IPBC, 3) were physically mixed in dichloromethane (DCM) and processed into solid microspheres by using emulsion solvent evaporation method. Five different compositions with varying PS/PCL ratio were tested. The phase morphology of the microspheres was studied using Phase imaging atomic force microscopy (AFM) of polished cross-sections. Scanning electron microscopy was utilized to assess the distribution of IPBC in the polymer microspheres. The phase separation of the PS and PCL polymers in solvent cast films was assessed using polarized light optical microscopy of 11 polymer blends (0-100 wt-% PCL in PS). The PS/PCL-IPBC microspheres were incubated in water at RT and the release of IPBC was studied using high performance liquid chromatography (HPLC) at time points 1, 7 and 30 days. The microspheres dispersed in water borne outdoor paint matrix were tested for their antifouling activity against moulds in vitro.

Two silane-based hybrid coatings were developed for surface modification of paper samples with an attempt to improve the hydrophobic properties of the paper surfaces. A phenolic resin was used along with the sol–gel coatings to impregnate the paper samples before they were pressed on to plywood surfaces. The surface characteristics of the sol–gel-coated paper were investigated by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), confocal laser scanning microscopy (CLSM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The surface chemical properties and water absorption of the laminated plywood was also evaluated. It was observed that the hybrid coatings had clearly different effect on the surface properties of the base paper compared to the industrially impregnated paper. The water absorption of the laminated plywood was decreased the most effectively by mixing the phenolic resin with the coating having an octyl group attached to the silane backbone.

Le traitement thermique du bois est utilise afin d'ameliorer la durabilite et de reduire l'hygroscopicite et les changements de dimensions du bois. Des echantillons de pin sylvestre et de sapin ont ete traites six heures a 225°C. Les eprouvettes etaient revetues par divers types de peintures de finition utilises usuellement sur les placages a l'exterieur, la menuiserie et les clotures en Finlande. Le rendement des eprouvettes traitees thermiquement et non traitees etait controle pondant trois annees d'exposition aux intemperies. La teneur en humidite des eprouvettes traitees etait d'a peu pres 40-60% inferieure a celle des eprouvettes en bois non traite. Le gondolage et les deformations en forme de cratere des planches traitees au cours de l'exposition n'ont pas ete observes. La couleur foncee initiale du bois traite n'est pas stable aux rayons UV. La resistance aux intemperies du bois traite etait amelioree par les peintures. La penetration des peintures au coeur du bois traite aussi bien que l'adherence etaient bonnes. Les peintures du commerce testees peuvent etre reccommandees pour le bois traite thermiquement.

The feasibility of using alkyd-acrylic copolymers as a barrier material was studied. Copolymers of tall oil fatty acid or rapeseed oil-based alkyd resin and polyacrylates were synthesized and films of these copolymers were prepared. Nuclear magnetic resonance spectroscopy revealed that after copolymerization the proportion of double bonds in alkyd resin was diminished due to grafting reactions. The mechanical properties, such as strength and flexibility, of the copolymer films were tested, and the performance of the films as water, oil, and oxygen barrier was evaluated. An increased amount of alkyd resin made the films more brittle and increased their oxygen permeability, however, at the same time their hydrophobicity was increased.

The VTT-Aalto-FIOH-IST joint RESCOAT (Novel Responsive Surfaces based on Active Hybrid Coatings Utilizing Encapsulation Technologies) project focuses on the development of novel active and responsive surfaces based on paint and thin coatings with encapsulated active agents. The developed polymeric or silica capsules are either slowly releasing or responsive to the external stimulus. The active agents in the capsules may have different functionalities being e.g. flame retardants, biocides, self-healers, antifreezers. By combining and further developing the existing know-how of coating and encapsulation technologies, the project aims to provide feasible functional solutions against e.g. biofouling, flare-up (delayed), wearing and scratches (self-healing) or ice nucleation. The developed coating and encapsulation technologies increase competitiveness of the products especially in the fields of construction, processing, electronic devices, machinery, infrastructure and transportation.

Recently, inorganic–organic hybrid coatings produced by the sol–gel route have proven to be a potential protective treatment for wooden surfaces. In this study, the effect of curing process on simulated antisoiling properties of sol–gel coating was investigated. The sol–gel coating was spray-coated on pine sapwood and cured with different temperature and time combinations. The antisoiling properties were studied by measuring the water contact angle of the coating after different curing processes. In addition, abrasion resistance and contact angle of oleic acid were measured. An optical profilometer was used to investigate surface roughness of the coating. Sufficient hydro- and oleophobicity were obtained with all of the curing parameters. The comparison between curing parameters showed that lower temperature and 1–3 h curing time leads to significant improvement in the durability of the water and oil repellent properties of the coating.

Wood is thermally modified by heating and steaming in order to change its properties, e.g., to improve the biological resistance and to increase the hardness of wood. The structure of thermally modified Scots pine (Pinus sylvestris) was studied using wide-angle, small-angle and ultra-small-angle X-ray scattering methods. Modification temperatures varied from 100 to 240°C. No marked changes in the microfibril angle distribution were observed. The mass fraction of crystalline cellulose in wood (the crystallinity of wood) and the size of cellulose crystallites increased above 150°C. After modification at 230°C for 4 h the thickness of the cellulose crystallites increased from 3.1 to 3.4 nm. Thermal modification had no effect on the orientation of the voids, but an increase in the porosity of the cell wall was observed. The distance between cellulose crystallites was approximately 4.7 nm in hydrated wood and a decrease in order between microfibrils was observed at 160–200°C.

In the present study the performance of boards treated by ThermoWoodr process were studied above ground and the results given are based on a "modified" horizontal double- layer test. The base layer of boards was in direct contact with ground and the conditions were much harder than in the standard method. After six years' exposure clear differences were found between untreated Scots pine and treated ones. In all cases thermal modification improved the performance. The greatest differences were discovered in boards located in base and lower boards of the double layer test. The best performed thermally modified pine heartwood, where only very little decay was found in base layer boards laying against the ground. Other layers were not attacked. The same trend was detected with Scots pine sapwood, but already some decay was also present in lower and top layer of boards. The smallest differences between modified and unmodified were found in upper layer of boards, which mainly suffered from blue stain and cracking. Also in this occasion pine heartwood performed better than sapwood boards. In addition, measured moisture content figures were in good correlation with found decay rates.