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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]

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]

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]

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.