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The effects of 1-hydroxybenzotriazole (HBT) and the natural laccase mediators gallic acid, caffeic acid and p-hydroxybenzoic acid, on the enzymatic bleaching of flax pulp were compared. The treatment was performed under atmospheric air and oxygen pressure, and, for the first time, monitored by thermogravimetric analysis (TGA) for comparison with chemical analysis, FTIR and X-ray diffraction (XRD) spectroscopies. Thermogravimetric data were simulated by applying a nucleation kinetic equation to a combustion model based on four pseudo-components (hemicellulose, amorphous and crystalline cellulose, and lignin). The results thus obtained show that the effects of the natural mediators are similar to those of HBT and lead to increased order in cellulose microfibril surfaces. An increase in pulp crystallinity was additionally exposed by the XRD and FTIR techniques, and a reduction in microfibril equatorial size by the XRD patterns. Simulated DTG curves were used to determine the kinetic parameters for thermal degradation., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

High-quality flax pulp was bleached in a short totally-chlorine-free (TCF) sequence. The LP biobleaching sequence includes an enzyme treatment with laccase in the presence of HBT as mediator (L stage) and a hydrogen peroxide stage (P stage). The operating conditions for the laccase HBT system were optimized by using a sequential statistical plan involving four variables, the influence of which on the properties of the pulp after the P stage was examined over enclosed operation conditions regarding a future industrial application. Mathematical models accurately predicting both pulp properties in terms of the previous four variables. This biobleaching sequence allows obtaining an increase in ISO brightness of 40% and a delignification of 80%. Process variables optimization in flax pulp biobleaching allows establishing the application conditions most appropriated to obtain certain pulp properties and that turn out to be easily adaptable to existing industrial processes. As a novelty, toxicity measurements were determined in L stage effluents. The results of toxicity show that it is possible to apply this LP sequence without having a negative environmental impact.

Wheat and oilseed flax straws were studied as raw material for papermaking. Two different aspects were investigated to valorize these agricultural byproducts: the capacity to recover some phenolic compounds and the use of the resulting cellulose fibers in papermaking. Straw phenolic compound composition was analyzed to determine the different accessible molecules and their available quantity. Ferulic acid, coumaric acid, vanillic acid, and vanillin were found in both wheat and oilseed flax straws. To enhance the release of these phenolic compounds, enzymatic treatments with feruloyl esterase and xylanase, two enzymes known for their role in lignin destructuration, were tested. These treatments increased the amount of phenolic compounds released, destructured hemicellulose and lignin, and improved the soda cooking conditions of pulps with the reduction of chemical charge need in the papermaking process. Phenolic compound production from this process could enhance the cost-effectiveness of papermaking from annual plants.

MS Tunis, Dār al-kutub al-waṭaniyya, 7116, is the only extant manuscript containing a complete copy of the Isḥāq/Ṯābit version of the Almagest. Paul Kunitzsch has underlined the close similarities between the marginal notes in the Tunis manuscript and those in Gerard of Cremona's Latin translation of the Almagest , so that Kunitzsch has concluded that Gerard of Cremona had a manuscript close to the Tunis manuscript before him during the revision of his translation of the Almagest. A note in MS Tunis, Dār al-kutub al-waṭaniyya, 7116, points out that this manuscript was copied from a model owned by al-Arawšī, a bibliophile living in Valencia famous for the size of his library, a significant part of which was looted by al-Maʾmūn b. Ḏī l-Nūn and sent to Toledo, arguably shortly before Ṣāʿid al-Andalusī wrote his Ṭabaqāt al-umam. Based on MS Tunis, Dār al-kutub al-waṭaniyya, 7116, the present contribution explores the significance of al-Arawšī's looted library as an important link between Umayyad Cordoba and Toledo. It also calls attention to the highly unusual paper of MS Tunis, Dār al-kutub al-waṭaniyya, 7116, made of woven fibers, maybe flax. Résumé: Le manuscrit de Tunis, Dār al-kutub al-waṭaniyya, 7116, est le seul manuscrit existant contenant une copie complète de la version d'Isḥāq/Ṯābit de l' Almageste. Paul Kunitzsch souligna les fortes similitudes entre les notes marginales du manuscrit de Tunis et celles de la traduction latine de l' Almageste par Gérard de Crémone, de sorte qu'il conclut que Gérard de Crémone avait devant lui un manuscrit proche du manuscrit de Tunis lors de la révision de sa traduction de l' Almageste. Une note dans le manuscrit de Tunis, Dār al-kutub al-waṭaniyya, 7116, signale que ce manuscrit a été copié d'après un modèle appartenant à al-Arawšī, un bibliophile vivant à Valence et célèbre pour la taille de sa bibliothèque, dont une importante partie fut pillée par al-Maʾmūn b. Ḏī l-Nūn et envoyée à Tolède, sans doute peu avant que Ṣāʿid al-Andalusī ne rédige ses Ṭabaqāt al-umam. S'appuyant sur le manuscrit de Tunis, Dār al-kutub al-waṭaniyya, 7116, la présente contribution explore l'importance de la bibliothèque pillée d'al-Arawšī comme lien essentiel entre la Cordoue omeyyade et Tolède. Elle porte également une attention particulière au papier très inhabituel du manuscrit de Tunis, Dār al-kutub al-waṭaniyya, 7116, fait de fibres tissées, peut-être du lin. [ABSTRACT FROM AUTHOR]

Purpose This paper aims to investigate the effect of acidity on the morphology of archeological paper, especially in the presence of colors and whether natural pigments play a role in the process of degradation.Design/methodology/approach The morphological changes in the cellulosic fibers of the manuscripts because of acidity were investigated using environmental scanning electron microscope (ESEM). Ten historical samples were collected from different manuscripts suffering from acidity. X-ray diffraction was used to identify the inks and pigments that were used in some samples. Additionally, Fourier transform infrared microscopy was used to identify the binding medium.Findings The results confirmed that carbon ink, ultramarine, cinnabar and gold pigments were applied to some manuscripts with Arabic gum. As for ESEM investigation, the results proved that acidity badly affected the integrity of the cellulosic fibers resulting in their embrittlement. The micrographs showed differences in fiber degradation according to pH value. The presence of inks and pigments increased the degradation extent resulting from acidity.Originality/value This paper addresses a specific need to study the behavior of degradation in paper manuscripts, thus helping the conservators find solutions to the phenomenon. [ABSTRACT FROM AUTHOR]

Natural fibers are gaining much interest in composite materials because of their potential to replace conventional glass fibers. In particular, unidirectional flax fiber composites have shown excellent mechanical properties with different thermoset matrices. However, few data are available when they are made with a biodegradable thermoplastic matrix. This paper compares the mechanical properties of two types of unidirectional flax composites using polylactic acid as the matrix: one made with layers of aligned flax rovings alone and the other containing an additional paper layer fabricated using paper making techniques. The results show that specific tensile properties of the flax/PLA (252 MPa·cm 3 ·g −1 ) and flax-paper/PLA (217 MPa·cm 3 ·g −1 ) composites are similar to those made using woven glass fabrics impregnated with epoxy (227–278 MPa·cm 3 ·g −1 ). Very high impact strength (600 J/m) was also obtained for UD flax-paper composites compared to unreinforced resin (15 J/m). Together these mechanical properties are promising for industrial applications of this new reinforcement. [ABSTRACT FROM AUTHOR]

Lignocellulosic crops like kenaf, flax and hemp have been extensively studied the last years with the help of new technology and many new products fabricated with them are ready for the market or have already been marketed. Both the core material and the bast fibers of these crops are ideal feedstocks for the production of yarns and paper of high quality, for rendering flame retardant properties to composites reinforced with them, for the production of energy via a sustainable way without polluting the environment and for use as alternative materials to wood for the manufacturing of panels like particleboards and fiber boards (MDF, HDF, etc.). The investigation of lignocellulosic feedstock as potential source for the sustainable production of materials, products and energy has resulted in promising solutions for the successful replacement of their counterparts made from fossil raw materials. However, the related industries still have some challenges to face, like the cost of materials from lignocellulosic plants in comparison with those derived from fossil sources and the availability of the feedstock throughout the year. [ABSTRACT FROM AUTHOR]

Abstract: Natural continuous bast fibres (hemp, flax, etc.) are gaining popularity in composite materials because they can advantageously replace glass fibres. It is found that intrinsic properties of unidirectional (UD) composites are almost equivalent to those of unidirectional glass fibre composites. Unfortunately it is difficult to get repeatable results because of the inherent variability in the properties of bast fibres compared to glass fibres. Their quality is largely affected by the weather conditions, the extraction location along the plant and the techniques used to extract them (retting, bleaching, etc.). In this work, unidirectional hemp/paper/epoxy and flax/paper/epoxy composites are manufactured by adding one or two sheets of paper at the surface of a unidirectional layer of hemp or flax fibres before molding. The composites are tested under tensile loads and the results compared with those obtained for UD composites made without paper. The results show a significant increase in strength and modulus repeatability when the paper layer is present. A significant increase in strength and modulus was also obtained compared to the base epoxy properties. The resin permeability of the flax–paper reinforcement has also been evaluated and compared to that of a standard glass fabric. Globally, the results suggest that adding thin sheets of paper at the surface of reinforcement layers stabilizes and increases the composite strength but slightly reduces the Young’s modulus. However the permeability of the flax–paper reinforcement was much lower than that of the glass fabric. Modifications to the paper architecture will be required to improve this aspect. [Copyright &y& Elsevier]

Hemp is a primary substance for papermaking, having been used for 2,000 years in this capacity. In the 20th century wood pulp came to replace hemp and other long fibres, and this has been an environmental disaster. Recent efforts to re-introduce hemp fibres into paper pulp are under way, with a number of writing papers having been manufactured in Europe and North America. However, most of these were done in small batches. Most papermills in southeast Asia produce 500,000 tons or more annually, whilst mills in the West tend to be small, specialty paper mills. Hemp is used rather consistently for fine papers, including cigarette paper and cosmetic tissue paper, but writing paper may continue to be made from trees until we run out and are forced to use other material. One large papermill in Germany, Gmund (which is distributed in the UK by The Hemp Shop) is starting to catch up, with a number of different papers including writing paper now being made in increasingly larger batches. A number of other companies are also offering hemp papers, ranging from writing paper to wallpaper. Part of the issue is the fact that the hurd, which is lower in cellulose content that the bast, can be used for paper, as demonstrated by the US government in the early 20th century. doi:10.1300/J237v12n02_08 [ABSTRACT FROM PUBLISHER]

Commercially available paper, flax, glass wool and rock wool insulation materials were tested for sensitivity to moisture and the ability of fungi to grow on them under different moisture regimes. Three levels of moisture were used, ambient, simulated rain and water holding capacity. After wetting, the materials were inoculated with a mixture of fungi and incubated at 26°C in boxes with high moisture levels for 4 weeks. The greatest degree of fungal growth was observed on paper and flax insulation materials initially conditioned to ambient moisture levels. Paper and flax insulation were strongly affected by moisture, with all treatments showing losses in dry mass of approx. 20%, except for paper subjected to simulated rain treatment in which the loss was 39%. Glass and rock wools were not sensitive to moisture and were resistant to fungal degradation, showing only traces of fungal growth and minimal loss in dry mass over 4 weeks. [Copyright &y& Elsevier]