TiO2‐Oligoaldaramide nanocomposites as efficient core‐shell systems for wood preservation

Homogeneous core‐shell systems were obtained with a growth, in controlled steps, of several oligoamides on TiO₂ nanoparticles. Derivatives of natural compounds, such as l ‐tartaric acid and α,α′‐trehalose, were used as diesters in the polycondensation reactions with ethylenediamine. TiO₂ anatase was chosen because of its high photo‐activity and its antimicrobial activity. The TiO₂ nanoparticles had been previously activated then functionalized using two different coupling agents, and finally, the TiO₂‐oligoamide nanocomposites were synthesized using two synthetic pathways. The final products were characterized by ¹H NMR, ¹³C NMR, FT‐IR, and transmission electron microscope. These nanocomposites can show improved properties in comparison with the single components (TiO₂ nanoparticles or oligoamides), which are useful in many fields, such as antimicrobial coatings for surfaces in cultural heritage conservation. A nanocomposite (TiO₂‐polyethylenetartaramide) was used for applicative studies, and it has shown a good efficacy against fungal attack by Trametes versicolor on wood specimens (Fagus sylvatica). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42047.     

Improving water solubility of poly(acrylic acid‐co‐styrene) copolymers by adding styrene sulfonic acid as a termonomer

Acrylic acid is often used to make water‐soluble polymers while styrene is often modified to add special functions to polymers. However, when styrene and acrylic acid are copolymerized, the resulting polymer is much less water soluble. To regain water solubility, the effect of styrene sulfonic acid on solubility of poly(acrylic acid‐co‐styrene) copolymers was investigated. Even though acrylic acid polymers are known for their water solubility, the presence of styrene units within acrylic acid copolymers reduces the solubility of the copolymer substantially at the natural pH of the solutions. By adding styrene sulfonic acid as a termonomer, polymers that are water soluble at the natural pH of the polymerization could be obtained. The solubility of the polymer after removal of the solvent and by redissolving at different concentrations and pH levels is also reported. Solubility increases at higher pH especially with low styrene concentration in the copolymer. It was found that incorporation of as little as 5 mol % of styrene into poly(acrylic acid) reduced the aqueous solubility to less than 0.5 g dL^?1 at pH 7. Upon adding 7 mol % styrene sulfonic acid as a termonomer, the water solubility increased to 5 g dL^?1 at pH 7. At higher levels of styrene, more styrene sulfonic acid was needed, especially at low pH. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Valorisation of waste fractions from autohydrolysis of selected lignocellulosic materials

Non‐isothermal processing of lignocellulosic materials in aqueous media (autohydrolysis reaction) under mild conditions leads to solutions containing valuable chemicals (oligosaccharides, sugars and acetic acid) and other, undesired, compounds (belonging to the extractive and acid‐soluble lignin fractions) which have to be removed in further purification treatments. Liquors obtained by non‐isothermal autohydrolysis of Eucalyptus globulus wood and corncobs under a variety of operational conditions were extracted with ethyl acetate in order to remove non‐saccharide components, and the suitability of the fraction dissolved in the organic phase was assayed for possible utilisation as an antioxidant. The yield and antioxidant activity of ethyl acetate extracts (measured by the α,α‐diphenyl‐β‐picrylhydrazyl (DPPH) radical scavenging capacity) showed a strong dependence on the autohydrolysis conditions. The antioxidant activity of extracts obtained under selected operational conditions compared well with synthetic antioxidants. © 2003 Society of Chemical Industry     

Preparation of microgel composite hydrogels by heating natural drying microgel composite polymers

Acrylamide‐co‐2‐acrylamido‐2‐methylpropane sulfonic acid‐based microgel composite (MC) hydrogels were prepared by heating natural drying MC polymers. It can reduce the influence of water content on the hydrogel properties. The natural drying MC polymer was swelling when the microgel content exceeded 0.5. It was soluble when the microgel content was 0.25, which was used to investigate the heating conditions. Under 50°C, MC hydrogels was obtained and hydrogen bonding was the reason for their formation. The tensile strength increased and the tensile elongation decreased as the heating time increased. When the heating time was 3 h, the tensile elongation decreased, as the heating temperature increased from 50°C to 80°C. However, the tensile strength increased first and then decreased. Under 60°C, the MC hydrogel had a high tensile strength of 155.3 kPa and a high tensile elongation of 313.3%. The more crosslinking density and the formation of covalent crosslinking bonds between the microgel particles and hydrogel matrix led to an increase in the tensile strength. However, the excess crosslinking of the polymer chains under high temperature could reduce the tensile strength. The tensile strength increased as the microgel content increased to 0.75 and then decreased as microgel content further increased. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40841.     

Water‐soluble polymers and gels from the polycondensation between cyclodextrins and poly(carboxylic acid)s: A study of the preparation parameters

Native cyclodextrins (CDx) and some of their derivatives were reacted with poly(carboxylic acid)s (PCAs) [citric acid (CTR), 1,2,3,4‐butanetetracarboxylic acid (BTCA), and poly(acrylic acid) (PAA)]. These reactions were carried out in the dry state at a temperature greater than 140°C in air or in vacuo. They resulted in water‐soluble and insoluble polymers formed by polyesterification between CDx and PCA. In this study, the parameters of the reaction were studied, and their influence on the water solubility or swellability of the obtained polymers was investigated. High reaction temperatures, high PCA/CDx molar ratios, and long reaction times preferably yielded insoluble gels, whereas softer conditions resulted in very soluble polymers. The gels could swell up to 10 times their initial volume in water, and the water‐soluble fraction had a solubility of 1 g/mL. A reaction mechanism was proposed that required the use of PCA carrying at least three neighboring carboxylic groups (CTR, BTCA, and PAA), and it was confirmed experimentally by the unsuccessful use of some dicarboxylic acids. A preliminary characterization by Fourier transform infrared spectroscopy and size exclusion chromatography was also conducted. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 433–442, 2005     

Preparation and cell morphology of ethylene‐vinyl acetate copolymer (EVA)/wood‐flour foams with low density

The main objective of this study is to obtain ethylene‐vinyl acetate copolymer (EVA)/wood‐flour foams with low density (< 0.2 g/cm³) using chemical blowing agent. Stearic acid was used as a compatibilizer to improve not only the compatibility between wood‐flour and EVA but also the compatibility between moisture and EVA in this study. The effects of wood‐flour content on the density and mechanical properties of EVA/wood‐flour foams were studied. Also, the effects of content of stearic acid on the cell morphology of EVA/wood‐flour foams were investigated. The shape of EVA/wood‐flour foams with 20% wood‐flour content becomes more uniform with increasing content of stearic acid. The most stabilized shape of the foams is obtained with 5 wt % stearic acid content. The density of EVA/wood‐flour foams with 20% wood‐flour and 5 wt % stearic acid is 0.11 g/cm³. With increasing content of stearic acid, more gas remains in the EVA matrix and consequently, average cell size and density increase. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40894.     

Ferulic acid as a comonomer in the synthesis of a novel polymeric chain with biological properties

In this study, ferulic acid was copolymerized with methacrylic acid to obtain a useful material with both antioxidant and antifungal properties. An ascorbic acid/hydrogen peroxide redox pair was used as a water‐soluble and biocompatible initiator system to prime the one‐pot polymerization reaction. The obtained material was characterized with gel permeation chromatography, Fourier transform infrared spectroscopy, ultraviolet spectroscopy, and fluorescence analyses, and the disposable phenolic group content was determined to verify the insertion of ferulic acid into the polymeric backbone. Finally, the antioxidant and antifungal activities were demonstrated toward the hydroxyl radical and Aspergillus niger, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Manufacture of Microcrystalline Cellulose from Eucalyptus globulus Wood Using an Environmentally Friendly Biorefinery Method

In this work, hemiceluloses and lignin were solubilized by successive steps of autohydrolysis and delignification, and the resulting solids were processed to obtain microcrystalline cellulose. Eucalyptus globulus wood chips were treated with hot, compressed water under selected conditions to cause the hydrolytic breakdown of heteroxylan into substituted saccharides. The xylan-depleted solids were treated with acetic acid under optimized conditions to remove lignin, leaving a solid phase with high cellulose content. This latter was subjected to Totally Chlorine Free (TCF) bleaching to yield microcrystalline cellulose. These sequence autohydrolysis-organosolv delignification-TCF bleaching enabled the selective separation of hemicelluloses (which were mainly converted into soluble saccharides), lignin (as compounds soluble into acetic acid), and microcrystalline cellulose, according to an environmentally friendly biorefinery method.     

Water soluble trehalose-derived oligoamides

A new family of oligotrehaluronamides was synthesized through the polycondensation of α,α-trehaluronic acid dimethyl ester and different diamines or polyamines. In particular, diamines with different molecular structure (1,n-alkylene diamines, aromatic diamine, and alkyleneoxydiamine) were used in order to modulate the molecular weights and the physical characteristics of the products, such as T_g, hydrophilic or hydrophobic properties, and solubility. α,α-Trehaluronic acid was obtained from a renewable source as α,α-trehalose. The syntheses of oligotrehaluronamides were carried out in different solvents such as ethanol, methanol, THF and DMSO, using triethylamine as catalyst. All the compounds obtained in this study were characterized through FT-IR and NMR spectroscopy. The molecular weights were evaluated by ¹H-NMR and in some cases compared with those obtained from ESI-MS spectrometry. Glass transition temperatures and melting points were detected by differential scanning calorimetry. Low molecular weight oligoamides, containing several hydroxyl groups, are water-soluble and could be used in water-based formulations.     

Synthesis,swelling behaviors,and slow‐release characteristics of a guar gum‐g‐poly(sodium acrylate)/sodium humate superabsorbent

Superabsorbents used in agricultural and ecological projects with low‐cost, slow‐release fertilizers and environmentally friendly characteristics have been extensively studied. The use of a natural polymer as the matrix and then further polymerization with some functional material has become the preferred method. In this work, with natural guar gum (GG), partially neutralized acrylic acid, and sodium humate (SH) as the raw materials, ammonium persulfate as the initiator, and N,N′‐methylenebisacrylamide (MBA) as the crosslinker, GG‐g‐poly(sodium acrylate) (PNaA)/SH superabsorbents were synthesized through a solution polymerization reaction and were characterized with Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The effects of the SH content and MBA concentration on the water absorbency were investigated. The results showed that the introduction of SH into the GG‐g‐PNaA system could improve the water absorbency, swelling rate, pH‐resistant property, and reswelling capability, and the superabsorbent containing 15 wt % SH had the highest water absorbency of 532 g/g of sample in distilled water and 62 g/g of sample in a 0.9 wt % NaCl solution. The slow release in water and water retention in sandy soil tests revealed that the superabsorbent could act as a fertilizer as well as an effective water‐saving material for agricultural applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Gewinnung molekulareinheitlicher N-Propionyl-oligo-ε-aminocapronsäurepropylamide aus Oligokondensaten durch Gelpermeationschromatographie

N-propionyl-oligo-ε-aminocaproic-acid-propylamides have been prepared by transamidation of caprolactam with propionic acid propylamide. The oligocondensate contains no cyclic compounds, and is nearly free from linear amides with terminal amino or carboxy groups. Variations in the conditions of transamidation change the distribution of chain length. The oligocondensates are separated into individual compounds by gelpermeation chromatography using Sephadex LH-20 and phenol/ethanol/water (1:2.6:1.6 v/v) as eluant. The oligoamides have been isolated up to the pentadecamer. Sufficient amounts of material for physico-chemical measurements are easily obtained by this procedure.     

Hydrothermal Liquefaction of Cypress: Effect of Water Amount on Structural Characteristics of the Solid Residue

Hydrothermal liquefaction of cypress was performed in an autoclave with various amounts of water. The obtained acid‐soluble and acid‐insoluble solid residues were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, sugar analysis, elemental analysis, and nuclear magnetic resonance to help understand the reaction mechanisms of this process. The characteristics of solid residues were significantly affected by the water amount. Cellulose was more stable at high water amount and hemicelluloses were much more reactive than cellulose. Comparison of nuclear magnetic resonance spectra of milled wood lignin and milled solid residues indicated a significant cleavage of the side chains. The components of milled solid residues were mainly derived from decomposition and repolymerization of lignin. The decomposition of the side chains was substantial for lignin depolymerization during hydrothermal liquefaction.     

Water‐soluble poly(ethylene glycol) prodrug of pemetrexed: Synthesis,characterization, and preliminary cytotoxicity

Pemetrexed is a novel antifolate of antimetabolite with multiple enzyme targets involved in both pyrimidine and purine synthesis. It has entered the clinical usage due to favorable profiles especially in the cancer treatment of mesothelioma and non–small‐cell lung carcinoma. But it presents numerous challenges associated with poor water solubility and unstability in its original form of glutamic acid. The aim of this study is to solubilize pemetrexed by designing and synthesizing its aqueous‐soluble prodrug using high aqueous‐soluble polymeric carrier poly(ethylene glycol) (PEG). A new type of soluble pemetrexed prodrug was synthesized with dihydroxyl PEG and a single amino acid linkage, and was extensively characterized using ¹H‐NMR, ¹³C‐NMR, Fourier‐transform infrared, and matrix‐assisted laser desorption time of flight mass spectrometry. In addition, the prodrugs were evaluated for the drug loading capability, the aqueous solubility, and the preliminary in vitro cytotoxicity. The results indicate that the new PEGylated pemetrexed conjugates possess enhanced water solubility and stability, and provide another feasible choice of the pharmaceutical form of pemetrexed in the clinical application. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and evaluation of a dispersant for gypsum paste from acid hydrolysis lignin

The preparation of dispersants with carboxyl groups from acid lignin (a byproduct in the saccharification process of woody materials that are renewable resources) was investigated, and their dispersion efficiency was evaluated. In this study, sulfuric acid lignin (SAL) was selected as a representative acid lignin. To convert SAL to water‐soluble polymers, it was first subjected to phenolation with sulfuric acid to enhance its chemical reactivity. The introduction of a carboxy group was carried out with two methods. One was carboxymethylation with bromoacetic acid, and the other was the Mannich reaction with glycine, sarcosine, and iminodiacetic acid. The carboxymethylation product [carboxymethylated phenolized sulfuric acid lignin (CP‐SAL)] with 1.4 carboxymethyl groups per phenolated phenylpropane lignin base unit was soluble in water. The Mannich reaction products were also soluble in water with a lower addition of carboxyl groups than that for CP‐SAL. Surprisingly, all the prepared water‐soluble polymers possessed a higher dispersibility for gypsum paste than commercial lignosulfate. This may be due to the higher molecular weights of acid lignin derivatives. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2508–2513, 2005     

Multiporous microstructure for enhancing the water absorption and swelling rate in poly(sodium acrylic acid) superabsorbent hydrogels based on a novel physical and chemical composite foaming system

In this article, we report a novel physical and chemical composite foaming system, which was used to successfully prepare high‐performance and low‐cost composite superabsorbent [poly(sodium acrylic acid) (PAA–Na)] hydrogels based on acrylic acid by free‐radical polymerization in a water bath under a nitrogen atmosphere without the use of any organic solvents. The prepared hydrogels showed superabsorbent properties, high water‐absorption abilities and swelling rates, a lighter packing density, and a multiporous microstructure. Fourier transform infrared spectroscopy and scanning electron microscopy revealed that the sodium dodecyl sulfate surfactant, sodium bicarbonate chemical foaming agent, and 1,1,2‐trifluorotrichloroethane physical foaming agent were evenly distributed and grafted onto the PAA–Na matrix. Water‐absorption, swelling rate, and packing density testing confirmed that the superabsorbent had a high water‐absorption ability and swelling rate and a lighter packing density. Furthermore, we investigated the effects of different foaming agents, including chemical and physical foaming agents, on the swelling and water‐retention capabilities of the superabsorbent hydrogels (SAHs).The results show that the combination of these foaming agents significantly improved the water‐absorbing capacity. With the help of these foaming agents, we obtained PAA–Na hydrogels without any organic solvents for posttreatment or special porogens; this is an environmentally beneficial way to prepare SAHs for hygiene and biomedical products. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44149.     

Synthesis and photosensitivity of acryloylmorpholine copolymers with a pendant (meth)acryloyl group

We have developed new photopolymers that have superior waterproof properties and that can easily interact with polyfunctional acrylate compounds, thus serving as hydrophobic photocrosslinking reagents. Acryloylmorpholine monomers whose homopolymers were less moisture absorbing than the usual water‐soluble polymers but were still water soluble to a good degree, were copolymerized with other acryloyl monomers. We then introduced the photosensitive (meth)acryloyl group to side chains of the resulting polymers. Among six copolymers examined, the copolymers composed of acryloyl morpholine, hydroxyethyl acrylate, ethyl, or methyl methacrylate, and methacryloyl isocyanate were found to have nicely balanced hydrophilicity and waterproof properties, in addition to good compatibility with hydrophobic photocrosslinking reagents. The composite polymers thus obtained were confirmed to be promising photopolymers usable even in a highly humid environment. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 684–692, 2003     

Morphological control of porous membranes based on aromatic polyether/water soluble polymers

This work describes the development of porous membranes based on blends of an aromatic polyether bearing main and side chain pyridine units (AP) with hydrophilic ionic polymers, like poly(sodium 4‐styrenesulfonate) (PSSNa) and its acid form (PSSH), or non‐ionic like polyvinylpyrrolidone and polyethylene glycol. Porous membranes were obtained after the removal of the water soluble polymers from the respective blend. The effect of various parameters such as water soluble polymer used (pore former), blend composition, casting solvent, and solvent evaporation level on porous structure formation was studied thoroughly. Specifically, SEM examination for the aforementioned systems indicated various porous morphologies depending on experimental conditions as well as thermodynamic and kinetic parameters occurring during their formation. The thermal properties of the membranes were influenced by the kind of the pore former, as revealed by thermogravimetric analysis. Special attention was paid to the systems AP/PSSNa and AP/PSSH to evaluate their miscibility via dynamic mechanical analysis and ATR‐FTIR spectroscopy. AP/PSSNa membranes have been preliminary used to test the water permeability for water purification. The tests revealed high water flux values at increased PSSNa concentrations. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44539.     

Release behavior from hydrogen‐bonded polymer gels prepared by pressurization

Our previous research showed that a simple ultra‐high‐pressure process made poly(vinyl alcohol) (PVA) solution into a macrogel and nanoparticles. To investigate the release properties of PVA hydrogels prepared by the ultra‐high‐pressure treatment, we prepared hydrogels containing model drugs by pressurizing a PVA solution with Alfa‐G Hesperidin or Oil Blue N as a water‐soluble or an oil‐soluble model drug, respectively. In the case of the oil‐soluble drug, an oil‐in‐water emulsion, Oil Blue N containing dodecane in a PVA solution, was used by homogenization before pressurization. The average diameter and the diameter distribution of oil droplets before and after the ultra‐high‐pressure treatment were almost the same. However, the PVA hydrogel prepared at 10,000 atm for 10 min exhibited the slowest release rate of model drugs. Thus, we found that the release rates of the model drugs from the PVA hydrogels were controlled by the degree of crosslinking in the resulting gels, which was determined from the operation parameters of the ultra‐high‐pressure treatment, such as the pressure, time, and concentration of the PVA solution. Therefore, an ultra‐high‐pressure process is promising for drug‐carrier development because of the nonharmful simple preparation process. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Wood flour: A new filler for the rubber processing industry. I. Cure characteristics and mechanical properties of wood flour‐filled NBR and NBR/PVC compounds

In this study, conifer wood flour was evaluated as a filler to NBR or NBR/PVC compounds studying it influence on their cure characteristics and mechanical properties. It was shown that the filling by wood flour offers a possibility to obtain high modulus high elastic or less elastic or rigid wood like vulcanizates by varying of both the filling level and NBR/PVC mass ratio.It was established that in contrary to the mineral fillers usually causing significant delay of the vulcanization process, the wood flour shows a tendency to reduce the optimum cure time, τ₉₀. Modulus M₁₀₀ and Shore hardness of the wood flour‐filled vulcanizates of NBR or NBR/PVC compounds in which NBR is predominant, increase in a compliance with the increase of M_max and DM when the filling level increases. The dependence is other when NBR and PVC are in equal amounts or PVC predominates. As a most probable explanation of the effect of the wood flour on the cure characteristics is accepted, the influence of the wood flour polar groups as well as of the presenting as wood flour humidity water molecules, the specific mechanical properties of the wood flour‐filled NBR or NBR/PVC compounds could be connected (to some extend) with a specific interface interaction between the wood flour particles and the polymer matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2734–2739, 2003     

Surface characterization of wood treated with boron compounds combined with water repellents

Longer weathering exposure periods are more reliable for end‐use performance evaluations of wood surfaces. This study aimed to investigate the effect of boron impregnation on the surface composition and color of Scots pine (Pinus sylvestris L.) wood exposed to 18 months of natural weathering in the West Black Sea Region of Turkey. All measurements were performed at 6 month intervals. Samples were first impregnated with boron compounds and then for a second time using five different water‐repellent materials. Polyethylene glycol and aluminum sulfate were introduced with the boric acid as single impregnations. With increased weathering time, the samples darkened, while sodium silicate kept the color change to a minimum. Nano boron‐impregnated samples exhibited more effective results than those impregnated with boric acid. The FTIR analysis results demonstrated that the impregnation process had caused significant changes in the chemical structure of the samples. The changes in the chemical structure of the wood resulting from the impregnation process were partially maintained during the weathering.