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Marrakchi Z.,LGP2 Laboratory of Pulp and Paper Science | Marrakchi Z.,Research Unity of Applied Chemistry and Environment | Oueslati H.,Research Unity of Materials Environment and Energy | Belgacem M.N.,LGP2 Laboratory of Pulp and Paper Science | And 2 more authors.
Composites Part A: Applied Science and Manufacturing

To the best of our knowledge, this is the first report of combining alfa fibres with polycaprolactone (PCL) and using impregnation as a processing technique. Alfa fibres were used to prepare films that were impregnated with PCL solutions in order to produce composites in a continuous process. The resultant composites were studied by scanning electron microscopy, which showed that the PCL matrix formed continuous and homogeneous films. Dynamic mechanical analyses showed that the rubbery plateau of the virgin matrix was significantly prolonged. Differential scanning calorimetry showed that the crystallisation capacity of the PCL matrix increased with an increase in the reinforcing cellulose. Finally, the produced composites were assessed by performing contact angle measurements of a water droplet, and it was revealed that this parameter increased up to 130°, indicating that their wettability had decreased drastically. © 2012 Elsevier Ltd. All rights reserved. Source

Khiari R.,CNRS Structural Engineering | Khiari R.,Research Unity of Applied Chemistry and Environment | Mauret E.,CNRS Structural Engineering | Belgacem M.N.,CNRS Structural Engineering | Mhemmi F.,Research Unity of Applied Chemistry and Environment

Every year, significant amounts of date palm rachises are accumulated in Tunisia. The rational valorisation of this renewable resource is therefore imperative, in order to fulfil the sustainability approach. In this context, this work aims to study the potential use of date palm rachises as a raw material for papermaking and to compare it with other sources of lignocellulosic fibres, such as wood, non-wood species, and agricultural wastes. For this purpose, soda-anthraquinone pulping of date palm rachis was performed giving rise to a yield of 45% (w/w). This value is similar to that obtained by pulping non-wood materials and is higher than that corresponding to the pulping of agricultural residues. The resulting pulps were subsequently refined using a PFI mill refiner at 0, 500, 1500, and 3000 revolutions, screened through a 0.15 mm mesh size sieve and used to produce conventional handsheets. Both pulps and papers were fully characterized in terms of morphological, chemical and physical properties, according to commonly used standards. The physical properties of the prepared handsheets were very similar to those displayed by other papers made of common lignocellulosic fibres. Furthermore, the pulps exhibited a good drainability together with excellent mechanical properties of the ensuing papers. For these reasons, date palm rachises could be considered as a potential source of fibres for papermaking applications. Source

Khiari R.,Research Unity of Applied Chemistry and Environment | Khiari R.,CNRS Structural Engineering | Mhenni M.F.,Research Unity of Applied Chemistry and Environment | Belgacem M.N.,CNRS Structural Engineering | Mauret E.,CNRS Structural Engineering
Bioresource Technology

In the present paper, the valorisation of two residues: Posidonia oceanica and date palm rachis was investigated. First, their chemical composition was studied and showed that they present amounts of holocellulose, lignin and cellulose similar to those encountered in softwood and hardwood. Extractives in different solvents and ash contents are relatively high. Moreover, ash composition assessment showed that silicon is the major component (17.7%) for P. oceanica. The high ash quantity and the low DP (about 370) may be considered as serious disadvantages of P. oceanica, in the pulping and papermaking context. Oppositely, the properties of rachis date palm and those of the ensuing pulp, obtained from a classical soda-anthraquinone cooking, demonstrated the suitability of this agricultural by-product for papermaking. Preliminary tests conducted on unrefined pulp suspensions and handsheets from date palm rachis in terms of freeness, Water Retention Value and mechanical properties allowed confirming the good quality of date palm rachis fibres. © 2009 Elsevier Ltd. All rights reserved. Source

Khiari R.,Research Unity of Applied Chemistry and Environment | Khiari R.,CNRS Structural Engineering | Mhenni M.F.,Research Unity of Applied Chemistry and Environment | Belgacem M.N.,CNRS Structural Engineering | Mauret E.,CNRS Structural Engineering
Journal of Polymers and the Environment

Different qualities of CMC were prepared from an agricultural residue (date palm rachis) and a marine waste (Posidonia oceanica). These starting lignocellulosic materials were used as such and after chemical pulping and bleaching. The carboxymethylation reaction was carried out in presence of NaOH (40%) and monochloroacetic acid (ClCH 2COOH, MAC), in n-butanol as the reaction solvent. The substitution degrees (DS) of the obtained CMCs varied from 0.67 to 1.62 and between 0.98 and 1.86, for P. oceanica and date palm rachis, respectively. The CP-MAS 13C-NMR spectra of the prepared polyelectrolytes displayed the presence of the main peaks associated with cellulose macromolecules (C1-C6) and that corresponding to carboxyl functions at around 175 ppm. Unfortunately, the peak attributed to methylene groups neighbouring carboxyl moieties are overlapped by C2 and C3, which renders them hardly detectable. Nevertheless, it is worth noting that the CP-MAS 13C-NMR spectra revealed the presence of different signals originating from residual impurities (ca. 27 ppm), such as traces of lignin macromolecules (110-150 ppm) and methyl groups attributed to hemicelluloses. Work is in progress to establish a more efficient purification procedure, in order to have more accurate values of DS. © 2010 Springer Science+Business Media, LLC. Source

Marrakchi Z.,CNRS Structural Engineering | Marrakchi Z.,Research Unity of Applied Chemistry and Environment | Khiari R.,CNRS Structural Engineering | Khiari R.,Research Unity of Applied Chemistry and Environment | And 3 more authors.
Industrial Crops and Products

The objective of this work is to study characteristics of chemical pulps (soda cooking process) and of paper obtained from Alfa, also known as Stipa tenacissima. For this purpose, Tunisian Alfa stems, and both unbleached and bleached pulps were characterized by determining their chemical composition as well as their morphological and physical properties. Through a detailed comparison with the other pulps obtained from various species, we show that the properties of Alfa stem fibres are intermediate between those of non-wood and wood plants, and most often close to those of Eucalyptus fibres. Refining process (PFI mill device) was then applied to the unbleached and bleached Alfa pulps. The modifications of the morphological properties of the fibres and the drainability and water retention values of the pulps were studied as a function of the refining degree. Here again, Alfa fibres exhibit a behaviour similar to that of Eucalyptus fibres, as the fibre shortening is very limited during the refining process. Finally, conventional handsheets with a basis weight of 65g/m2 were prepared from the unrefined and refined pulps. Their characterization showed that Alfa based papers present low density values and quite good mechanical properties, which are significantly enhanced by the refining treatment, particularly for the unbleached pulp. This study demonstrates the high potentiality of this non-wood species for papermaking applications. © 2011 Elsevier B.V. Source

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