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Paper manufacturers have long used silicone as the coating agent for release liners. However, silicone‐based release paper is very difficult to recycle due to covalent bonds between silicone and fibers. The most suitable solution to overcome this problem is to use alternative coating materials with adequate release properties, provided that they can be easily repulped in typical paper recycling facilities. We proposed a coating agent composed of phosphate esters and dimethylacetamide in order to manufacture a recyclable and efficient release paper. Analyses carried out on coated sheets showed that phosphate esters allowed the formation of a surface with adequate release properties (low peeling force and surface free energy). In addition, the residual adhesion values obtained with phosphate esters confirmed that they are well anchored on the backing paper surface, thus limiting the mass transfer to the adhesive tape. [ABSTRACT FROM AUTHOR]

Phosphorylated fibers offer a broad range of applications, particularly in thermal insulation, notably with wood fibers, provided they exhibit improved mechanical characteristics. Despite encountering challenges in applying traditional papermaking methods, the creation of paper or board sheets with phosphorylated pulp fibers remains a challenge. Findings suggest that phosphorylation-modified fibers show increased roughness. Moreover, in comparison with unbeaten kraft sheets (KF) and thermomechanical pulp sheets (TMP), those made from phosphorylated kraft fibers (PKF), using a cationic coagulant and a flocculant, demonstrate significant enhancements in burst index, break index, and tensile energy absorption by 2.12 times, 1.7 times, and 2.77 times, respectively. Similarly, phosphorylated TMP sheets, prepared with a dual polymeric system (coagulant/flocculant), exhibit improvements of 1.42 times, 1.33 times, and 1.82 times, respectively, in these properties. The study emphasizes the ameliorating effect of cationic polymeric agents on the charge impact of phosphorylated fibers on overall sheet quality, while also highlighting the substantial influence of hot-pressing lignin-containing paper on all determined physical properties. [ABSTRACT FROM AUTHOR]

The production of release coatings has been increasing in recent years because of their use in various fields. However, commercially available release coatings are regarded as non-recyclable. As a consequence, the repulping of these residues is difficult, and their presence in the recycling stream represents an important source of contamination. One solution to this problem is to use new coating materials that can replace the siliconized backing, provided that these new materials are recyclable. As a solution to this problem, the authors propose the use of alkylated phosphorylated fibers to produce an environmentally friendly and inexpensive release paper. The results show that a surface application of hydrophobic phosphorylated fibers reduces the surface free energy of the paper support, as well as the peel strength, which facilitates the separation of the adhesive tape. [ABSTRACT FROM AUTHOR]

Materials used in many sectors like building or transportation must respect flame resistance standards. In this work, a dispersion of flame retardant phosphorylated kraft fibers (PKF), used in replacement of aluminum trihydroxide (ATH) in a polyester resin of a glass‐reinforced composite laminate, and their impact on the flame retardancy of the material was investigated. SEM and EDS images showed a regular and homogeneous distribution of PKF in the resin matrix. The addition of PKF in the resin has a significant impact on the flammability parameters of the composite. For the tested experimental conditions, powdered PKF can be dispersed into the resin at a maximum powder/resin ratio of 20 wt% to maintain a low enough viscosity of resin for molding and procure a significant weight reduction of the laminate. However, there seems to be several unprotected areas in the material, by either PKF or ATH, that could promote flame propagation and smoke emission. Complete coverage of laminate with PKF will need to be achieved for a complete substitution of ATH. [ABSTRACT FROM AUTHOR]

Transverse compaction of fibre reinforcements has significant importance in the production of complex dry fibre preforms for the resin transfer moulding (RTM) process of composite materials. This work investigates, for the first time, the planar compaction of phosphorylated stacks of unidirectional (UD) reinforcements made of flax yarns held together by a thin layer of short flax fibres. Planar compaction tests were carried out to evaluate the influence of temperature and humidity on the creep percentage, thickness recovery, and permanent deformation of UD reinforcements prepared with and without phosphorylation. It appears that the creep percentage and permanent deformation are more important for phosphorylated reinforcements than for untreated ones. Increasing the compaction temperature and humidity results in an increase of the creep and permanent deformation of phosphorylated fibres. The tensile strength of phosphorylated fibres‐reinforced composites is lower than that of untreated ones while there is no effect on the tensile modulus. [ABSTRACT FROM AUTHOR]

Contamination of water resources by toxic heavy metals has significant impacts on environmental and human health. Their removal from aqueous media is essential to ensure water sustainability and to provide safe freshwater availability to population. Electrospun chitosan (CS) nonwoven mats are efficient at removing heavy metals from aqueous media. However, they suffer from low permeability and low‐mechanical strength. They are also unable to remove contaminants in a nonselective way. A bilayer sorbent media made of a porous phosphorylated cellulose substrate covered by electrospun CS nanofibers was developed to overcome those weaknesses. The hydrophilic composite shows good water permeability and mechanical strength with appropriate thermal and chemical characteristics. Adsorption tests with Cd(II) indicate that pseudo‐second order and Langmuir models best fitted experimental data, with a maximum adsorption capacity of 591 mg/g at 25°C. Adsorption with multielement samples containing Cr(VI), Cu(II), Cd(II), and Pb(II) also reveal their capability to remove them in a selective way. This mechanically resistant, hydrophilic, and permeable adsorbent media was able to capture both cationic and anionic metallic contaminants. [ABSTRACT FROM AUTHOR]

Porous silicon carbide (SiC) materials were fabricated using the polymer‐derived ceramics method with kraft pulp papers (KPP) and a commercial polycarbosilane, the allylhydridopolycarbosilane (AHPCS), as starting materials. For this, KPP, propargylated KPP, or phosphorylated KPP were used to be impregnated by the AHPCS, with or without Karstedt catalyst. The pyrolysed materials were characterized at different stages, by using thermogravimetric analysis (TGA) coupled with mass spectrometry, X‐ray diffraction (XRD), and scanning electron microscopy (SEM). Depending on the nature of the initial template, various architectured SiC ceramics were successfully obtained with adjustable porosities. The key role of the previous functionalization of the papers was highlighted in terms of interactions at the interface between the polymer and the lignocellulosic handsheets. It led to either replica or sacrificial template methods. Thus, it was possible to tune the open porosity of the porous carbon and β‐SiC materials between 14.8% and 92.9%, with ceramic yields varying from 12% to 71%. [ABSTRACT FROM AUTHOR]

ABSTRACT: This work aims to investigate the dielectric potential of microcrystalline cellulose, a green biosourced material, as a third constituent in the three‐phase composites based on ethylene vinyl acetate‐vinyl ester of versatic acid (EVA‐VeoVa) terpolymer and BaTiO3. For that, new green three‐phase composites were prepared using an economic and green process, with simple implementation at room temperature and using water as a solvent. Compared with the binary composite EVA‐VeoVa/BaTiO3, the three‐phase composite EVA‐VeoVa/BaTiO3/microcrystalline cellulose showed an improvement of the BaTiO3 particles dispersion, enhanced relative permittivity, and reduced dielectric loss, which explains the significance of this study. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46147. [ABSTRACT FROM AUTHOR]

ABSTRACT Acetylation is a common way to enhance interfacial adhesion between natural fibres and polymeric matrices in composites. This work investigates the effect of a solvent-free environmentally friendly acetylation treatment of short flax and kraft fibres on the impregnation behaviour and tensile properties of flax fibre/epoxy composites. Untreated and acetylated fibres have been used to prepare fibre mats, which were next studied for their morphology, their permeability to liquid epoxy, and their ability to adhere to the epoxy matrix after cure. The results show that acetylation enhances the roughness of flax fibres and improves fibre-matrix interaction, but reduces the permeability of the fibre mats and the intrinsic properties of fibres, thus leading to slightly lower composite modulus and strength. The proposed treatment is an interesting option to improve the affinity between natural fibres and polymeric matrices, but more work will be required to improve the interfacial adhesion without damaging the fibres. [ABSTRACT FROM AUTHOR]

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ABSTRACT An economic and environment friendly process was adapted to synthesize new dielectric composite materials. Using ethylene vinyl acetate (EVA)/vinyl ester of versatic acid (VeoVa) terpolymer as an aqueous emulsion provides a homogenous dispersion of BaTiO3 (BT) particles, due to the high viscosity and polarity of the vinyl resin (VR). Composites films were obtained from these dispersions by water evaporation. The evolution of the dielectric properties as a function of the BaTiO3 content, was correctly fitted by a Maxwell-Garnett model. This fitting of the experimental curve shows a good dispersion of filler in the vinyl resin and the particles separation by a layer of resin as expected for the preparation method used in this study. The VR/BT composites show good synergy between the dielectric properties of the different phases of the composites due to the formation of macrodipoles and to the strong interactions between polar EVA/VeoVa groups and the BaTiO3 particles surface. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44333. [ABSTRACT FROM AUTHOR]

Acetylation is one of the most widespread chemical treatments to improve the affinity of lignocellulosic fibers with polymeric matrices for the elaboration of several types of composites. In this study, the acetylation of flax and wood pulp (bleached softwood kraft pulp and thermomechanical pulp) fibers was carried out in conditions that respect the environment and are suitable for industrial use. The thermal stability of acetylated fibers was evaluated. The evolution of the hydrophobic/hydrophilic character of fibers was determined by contact angle measurements. The wettability of fibers by liquid epoxy resin was also evaluated to confirm the improvement of the affinity of acetylated fibers with the epoxy matrix. It was found that the hydrophilic character of fibers decreases with increasing reaction time, whereas the trend was less pronounced beyond specific reaction times. Acetylated fibers can therefore be potential candidates for replacing non-biodegradable reinforcing materials in composite applications. [ABSTRACT FROM AUTHOR]

Due to its physical properties and its ease of manufacture, paper is widely used in various engineering applications such as electrical insulation materials for components in high voltage technology. In this study, paper loaded with ferroelectric nanoparticles (BaTiO3 and SrTiO3) was made with fibers obtained from plants growing on the Moroccan soil [Halfa (Stipa tenacissima), Agave (Agave americana), Pennisetum (Pennisetum alopecuroides), Typha (Typha latifolia), and Junc (Juncus effusus)] and two commercial pulps (bleached softwood Kraft and newsprint grade thermomechanical pulps). A retention aid, cation polyacrylamide (Percol 292), was necessary to retain ferroelectric particles in the fibrous network and improve the dispersion of strontium titanate particles. The different pulp and handsheets used were characterized according to standard methods (Pulp and Paper Technical Association of Canada, PAPTAC). It is well known that annual and perennial plants contain high percentages of fines (length < 0.2 mm) and short fibers. The results show that there is a strong interdependence between the dielectric properties of the loaded paper and surface finish, porosity, dispersion level of ceramic particles, fines content, shape, conformability, and sheet formation. The single dielectric relaxation detected towards low frequencies is attributed to hydroxyl groups present on fiber surfaces, in ceramic particles and adsorbed water. [ABSTRACT FROM AUTHOR]

ABSTRACT Acetylation is one of the most interesting chemical treatments to improve the affinity of lignocellulosic fibers with polymeric matrices for the elaboration of several types of composites. In this paper, the acetylation of flax and wood pulp (bleached softwood Kraft pulp and thermomechanical pulp) fibers was carried out at room temperature in a solvent-free system with acetic anhydride in the presence of sulfuric acid as catalyst. The effect of acetylation on the fine structure of fibers was investigated by spectroscopic methods, while the extent of acetylation was quantified by weight percent gain. The effect of reaction time on fiber morphology was studied at macro- and microscale using scanning electron microscopy, optical microscopy, and fiber quality analysis. The evolution of the hydrophobic/hydrophilic character of fibers was determined by contact angle measurements. The wettability of fibers by liquid epoxy resin was also evaluated to confirm the improvement of the affinity of acetylated fibers with the epoxy matrix. It was found that the hydrophilic character of fibers decrease with increasing reaction time, whereas the trend was less pronounced beyond specific reaction times. Acetylated fibers can therefore be potential candidates for replacing nonbiodegradable reinforcing materials in composite applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42247. [ABSTRACT FROM AUTHOR]

Promising controlled release systems were prepared from renewable natural products. Paper, used as the system core, was made with commercial kraft pulp and with bleached lignocellulosic pulps extracted from local plants. The characteristics of those pulps (fines content and fiber length) as well as paper thickness, porosity, and roughness, were evaluated. Alginate served as the protective membrane. The releasability of Diclofenac as a function of time and pH was studied under constant temperature (37 °C) and constant stirring (200 rpm). Also the influence of the type of paper and the calcium alginate concentration in the protective layer were highlighted. The extent of release reached 80% in a basic medium in a variable time interval 7 to 16 h, whereas in an acid medium it did not exceed 24% in 33 h. Diffusion, Fickian diffusion, and diffusionerosion were judged to be important contributing mechanisms based on the Korsmeyer-Peppas kinetic model for those various matrixes. Different formulations were found to have significant controlled release properties that could be used in the prolonged release of the active ingredients. Because of the low release in acidic medium, the formulated system could be a good candidate to protect the active ingredient from acidic medium. [ABSTRACT FROM AUTHOR]

The properties of phosphorylated kraft fibers, including their flame retardancy and behavior in water, such as electrical charge and swelling capacity, were investigated in this study. Two different phosphorus contents and three forms of phosphorylated fibers (ammonium, acid, and sodium) were analyzed. All types of phosphorylated fibers exhibited high char formation and limiting oxygen index (LOI) values, indicating good flame retardancy. In particular, the ammonium form exhibited the best flame retardancy behavior and the highest LOI value. The charge density and swelling capacity of the kraft fibers were significantly increased by phosphorylation. Alkaline treatment following the phosphorylation reaction further increased the water retention value (WRV) and surface charge of the kraft fibers. Compared to unmodified kraft fibers, the phosphorylated fibers had lower absolute values of the negative zeta potentials, and these values were less affected by conductivity. [ABSTRACT FROM AUTHOR]

Chemical modifications of cellulose fibres (kraft pulp) in NaOH/H2O and NaCl/H2O systems were investigated. Handsheets were prepared that contained 25% of the modified fibres. Changes in the modified samples were examined by measuring their mechanical and optical properties and comparing them to those made with unmodified fibres. The observed differences were explained and supported by structural analyses, by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the NaOH/H2O pretreatment led to a significant deterioration of optical and strength properties of the handsheets. These modifications affected both the inner part of the crystalline cellulose (change from cellulose I to cellulose II) and the morphology of the fibers. Conversely, these properties slightly improved after propargylation, due to the propargyl functional groups. For the NaCl/H2O system, a significant enhancement of the mechanical properties of the handsheets was noted, such as an increase of up to 108% of the tear index. The propargylation further increased the tear index (by 157%). These enhancements were not accompanied by significant changes at both the micrometric and nanometric scales, except for the increase of the crystallinity index after propargylation. [ABSTRACT FROM AUTHOR]

p-Toluenesulfonyl cellulose was prepared by reacting cellulose in aqueous medium, instead of via traditional routes, which involve the use of DMAc/LiCl, or more recently, ionic liquids. The influence of several parameters on the reaction efficiency has been studied; amount of tosylchloride, presence of triethylamine, reaction time and use of sodium hydroxide or sodium chloride. The resulting p-toluenesulfonyl cellulose samples were characterized by means of FTIR and NMR spectroscopy. The effects of solvent on the crystalline change during tosylation were investigated by X-ray diffraction (XRD). The degree of substitution (DS) was determined by 1H NMR and confirmed by X-ray photoelectron spectroscopy (XPS). Tosylcelluloses with DS from 0.1 to 1.7 have been prepared. [ABSTRACT FROM AUTHOR]

Cyclodextrins are important building blocks in organic chemistry. This review deals with the role of click chemistry in this family of cyclic oligosaccharides, focusing on the different areas of chemistry, including chromatography, biological applications, the elaboration of superstructures, and metal detection, that benefit from this reaction. In this paper, attention is given to organic modifications by using functionalizations such as azidation and propargylation and to click chemistry grafting onto the two faces of cyclodextrins. Research papers where cyclodextrins are not directly involved in a click chemistry reaction are not considered. [ABSTRACT FROM AUTHOR]

Release paper is a special paper grade with one or both sides coated with non-sticking materials. Silicone is currently the only material used to produce release paper at the industrial level. Its remarkable properties and availability ensure product quality and sustainability of the industrial production. Meanwhile, the stability of silicone polymers raises serious environmental problems in terms of paper substrate recyclability. Studies are currently under way to evaluate the ability of phosphate esters as a new class of compounds capable of developing non-adhesive surface properties. This paper presents initial attempts to coat the paper with phosphate esters and to assess phosphate ester / fibrous substrate and phosphate ester / adhesive interactions. The results show that this class of compounds exhibits non-adhesive properties and, when coated on paper under certain conditions, can lead to a non-sticking surface. Despite the fact that there is a long way to achieve ester anchoring to surface fibers and to control the peeling force from an adhesive tape, preliminary results are encouraging. [ABSTRACT FROM AUTHOR]

Polysaccharides are complex but essential compounds utilized in many areas such as biomaterials, drug delivery, cosmetics, food chemistry or renewable energy. Modifications and functionalizations of such polymers are often necessary to achieve molecular structures of interest. In this area, the emergence of the "click" chemistry concept, and particularly the copper-catalyzed version of the Huisgen 1,3-dipolar cycloaddition reaction between terminal acetylenes and azides, had an impact on the polysaccharides chemistry. The present review summarizes the contribution of "click" chemistry in the world of polysaccharides. [ABSTRACT FROM AUTHOR]

A fast and simple reaction activated by microwave irradiation permits the “green synthesis” of propargylcellulose in an aqueous alkaline medium. The influence of several reaction parameters such as amount of propargyl bromide, reaction time or microwave activation on the reaction efficiency are reported herein. The propargylcellulose samples obtained, with degrees of substitution (DS) from 0.35 to 1.88, were characterised by means of FTIR and NMR spectroscopy. [ABSTRACT FROM AUTHOR]

• A novel electrospun Chitosan/Phosphorylated Nanocellulose biosorbent was prepared. • Phosphorylated Nanocellulose was added to improve the Cd2+ adsorption. • Phosphate groups (PO 4 2 -) were formed on the surface of electrospun nanofibers. • Langmuir isotherm best described equilibrium for Cd2+ removal. • Thermodynamic study showed the spontaneity endothermic reaction for adsorption. The removal of Cd(II) ions from aqueous solution was carried out using a new nanofibrous electrospun nonwoven sorbent made from Chitosan (CS) and Phosphorylated Nanocellulose (PNC). The sorbent material was characterized using SEM, EDX, AFM and FTIR. The sorption capacity reached 62.3 mg/g at pH 5.5 and 25 °C. The Cd(II) adsorption occurred rapidly and achieved equilibrium within 120 min. The pseudo-second order kinetic model best fitted experimental data. The sorption isotherm was also best described by the Langmuir model. The maximum adsorption capacity of Langmuir was 232.55 mg/g at 25 °C, and increased with temperature, which can be explained by the high affinity of amine and phosphate groups with cadmium on the surface of the nanofibrous mats. The thermodynamic study showed that the adsorption is a spontaneous endothermic reaction. This work confirmed that an electrospun nanofibrous mats based on CS and PNC can be used as an alternative material for the removal of cadmium ions, contributing to water sustainability. [ABSTRACT FROM AUTHOR]

This paper presents the effect of compaction parameters on the permeability to resin, tensile and flexural performances of unidirectional (UD) composites made of UD flax-mat reinforcements. In these reinforcements the UD fiber yarns are held together by a thin mat layer of short flax fibers. Reinforcements were compacted in dry or wet conditions at ambient or high temperature prior to permeability testing and composites molding with the resin transfer molding (RTM) process. A micrographic analysis of the morphology and structure of the laminates prior to and after tensile testing was also performed. It is found that hot and wet compaction do not change the permeability. Moreover, after molding with compacted reinforcements, the tensile strength increases while the tensile modulus is not affected. It also leads to a substantial increase in the flexural properties (strength and modulus). This means the chosen compaction parameters are appropriate for preforming this type of reinforcement. [ABSTRACT FROM AUTHOR]

Objective: Our objective was to assess the short-term effect of an estrogen cream on symptoms associated with provoked vestibulodynia., Methods: We undertook a double-blind randomized trial in women who had experienced dyspareunia satisfying the Friedrichcriteria for at least three months. We compared the daily application of 3 g of vaginal cream containing 1.875 g of conjugated estrogens for six weeks (estrogen group) with the application of a comparable cream without estrogens (placebo group). The main outcome was modification of dyspareunia,determined by a visual analogue scale of pain from the pretreatment period to the post-treatment period. Secondary outcomes were colposcopic evaluation of the vulva and pain reported during the swab test., Results: Of 69 women randomized, 61 participated for the full duration of the trial. Dyspareunia was significantly lessened in both groups (estrogen group: 7.4 ± 1.9 pre-treatment vs. 4.8 ± 3.0 post-treatment, P < 0. 01; placebo group:7.1 ± 1.9 vs. 4.9 ± 2. 7, P < 0.01), but the difference observed in terms of decrease between the two groups was not found to be significant (P = 0.5). Alternatively, the group treated with estrogen cream showed (1) a more substantial decrease of the pain reported at the orifices of the Bartholin’s glands when palpated with a swab (P < 0.01), and (2) a decrease of the inflammation observed at the orifices of the Bartholin’s glands orifices and the posterior fourchette (P < 0.01)., Conclusion: Applying a vaginal cream, whether it contains estrogens or not, for six weeks lessens dyspareunia. Adding estrogens to such a cream could facilitate a decrease of the inflammation observed at the orifices of the Bartholin’s glands and the vestibule.