Thermoplastic Films Based on Polyelectrolyte Complexes of Arabino Glucurono-Xylan and Polyethylenimine

This work investigates film formation using polyelectrolyte complexes (PECs) of xylan and polyethylenimine (PEI). Different xylan/PEI mass ratios (from 50/50 to 90/10) and pH values (5.0 and 7.0) are analyzed and both parameters have an effect on complex size and film properties. Furthermore, the mass ratio corresponding to the neutralization charge depends on pH. When xylan/PEI mass ratios are near the neutralization charge ratio, a coacervation process is observed. In this case, separation between the coacervate and the supernatant dilute phase is possible. In the supernatant, both concentrations, xylan and PEI, depend on pH. The complex suspensions are used to obtain films by PECs casting/evaporation process. For films obtained from the whole suspension, by increasing the xylan content the stress at break is improved (up to 23 MPa for 85/15, at pH 7.0) and the strain at break is decreased (to 2.5%). When only coacervate is used to prepare films, the tensile strength is higher, reaching a value of 37 MPa for 85/15 mass ratio. Dynamic mechanical thermal analysis shows that the glass transition temperature (Tg) of the films is affected by composition. The thermoplastic behavior of a 50/50 xylan/PEI film is confirmed using a hot-compression molding.Fil: Solier, Yamil Nahún. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Mocchiutti, Paulina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Inalbon, Maria Cristina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Zanuttini, Miguel Angel Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentin

Dissolved and colloidal substances (DCS) and the charge demand of papermaking process waters and suspensions: A Review

Dissolved and colloidal substances (DCS) in the process waters of paper machine systems can interfere with the retention of fine particles, retard the drainage of water from the wet web, and generally hurt the intended functions of various polyelectrolytes that are added to the process. This review considers publications that have attempted to characterize the nature and effects of different DCS fractions, in addition to some of the ways that paper technologists have attempted to overcome related problems. The consequences of DCS in a paper machine system can be traced to their ability to form complexes with various polyelectrolytes. Such tendencies can be understood based on a relatively strong complexing ability of multivalent materials, depending on the macromolecular size and charge density. Continuing research is needed to more fully understand the different contributions to cationic demand in various paper machine systems and to find more efficient means of dealing with DCS

Applying Ligninolytic Fungi on <i>Eucalyptus grandis</i> Wood for Pulping Pretreatment or Fractionation

The effects of three different fungal treatments on several technology characteristics of Eucalyptus grandis wood, were studied on industrial chips and blocks. The percentage of the substrate mass loss by the fungal treatment, and the relative amount of extractives and lignin were determined. The effective capillarity of wood, pH and total reducing sugars concentration in water-soluble fraction (WSF) were also determined. There was a reduced mass loss of the substrate by the fungal treatment (less than 3%). Gelatoporia subvermispora FBCC 313 showed the highestreduction in the Klason lignin content, the highestendoglucanase activity on the WSF as well asthe highest ability to increase the effectively capillarity in the radial wood direction. This last effect is interesting since it might facilitate the wood impregnation processes and therefore to reduce the consumption of reagents in industrial treatments.Facultad de Ciencias Agrarias y ForestalesCentro de Investigaciones en FitopatologíaFacultad de Ciencias Naturales y MuseoInstituto de Fisiología VegetalInstituto de Botánica "Dr. Carlos Spegazzini

Applying Ligninolytic Fungi on <i>Eucalyptus grandis</i> Wood for Pulping Pretreatment or Fractionation

The effects of three different fungal treatments on several technology characteristics of Eucalyptus grandis wood, were studied on industrial chips and blocks. The percentage of the substrate mass loss by the fungal treatment, and the relative amount of extractives and lignin were determined. The effective capillarity of wood, pH and total reducing sugars concentration in water-soluble fraction (WSF) were also determined. There was a reduced mass loss of the substrate by the fungal treatment (less than 3%). Gelatoporia subvermispora FBCC 313 showed the highestreduction in the Klason lignin content, the highestendoglucanase activity on the WSF as well asthe highest ability to increase the effectively capillarity in the radial wood direction. This last effect is interesting since it might facilitate the wood impregnation processes and therefore to reduce the consumption of reagents in industrial treatments.Facultad de Ciencias Agrarias y ForestalesCentro de Investigaciones en FitopatologíaFacultad de Ciencias Naturales y MuseoInstituto de Fisiología VegetalInstituto de Botánica "Dr. Carlos Spegazzini

Applying Ligninolytic Fungi on <i>Eucalyptus grandis</i> Wood for Pulping Pretreatment or Fractionation

The effects of three different fungal treatments on several technology characteristics of Eucalyptus grandis wood, were studied on industrial chips and blocks. The percentage of the substrate mass loss by the fungal treatment, and the relative amount of extractives and lignin were determined. The effective capillarity of wood, pH and total reducing sugars concentration in water-soluble fraction (WSF) were also determined. There was a reduced mass loss of the substrate by the fungal treatment (less than 3%). Gelatoporia subvermispora FBCC 313 showed the highestreduction in the Klason lignin content, the highestendoglucanase activity on the WSF as well asthe highest ability to increase the effectively capillarity in the radial wood direction. This last effect is interesting since it might facilitate the wood impregnation processes and therefore to reduce the consumption of reagents in industrial treatments.Facultad de Ciencias Agrarias y ForestalesCentro de Investigaciones en FitopatologíaFacultad de Ciencias Naturales y MuseoInstituto de Fisiología VegetalInstituto de Botánica "Dr. Carlos Spegazzini

Polyelectrolyte complexes for assisting the application of lignocellulosic micro/nanofibers in papermaking

A novel procedure based on the addition of polyelectrolyte complexes (PECs) onto the pulp containing lignocellulosic micro/nanofibers (LCMNF) is presented. This procedure allows increasing paper strength avoiding an excessive loss in drainability. LCMNF were obtained from partially delignified kraft pine sawdust using a high-pressure homogenizer. Cationic complexes (CatPECs) were prepared by adding the anionic polyelectrolyte solution (polyacrylic acid) on the cationic polyelectrolyte solution (poly(allylamine hydrochloride)). According to turbidity and surface morphology changes, an interaction between CatPECs and LCMNF could be established. Different CatPEC dosages (from 0.3 to 1.0% on pulp) were added on a recycled unbleached softwood kraft pulp containing 3% of LCMNF. For a PEC dosage of 0.75% on pulp, an optimum balances between negatively and positively charged materials [near to zero value of the logarithm of the colloidal titration ratio (logCTR)] was found. Britt Dynamic Drainage Jar test showed a high retention of fines and LCMNF for all PEC dosages. A maximum in retention value was obtained for the addition of 0.75% of PECs on pulp, dosage that was suggested as optimum by the logCTR. In addition, the best drainability value (18°SR) was obtained for this PEC addition level. Papermaking properties were clearly improved for all dosage of PECs. Particularly for a dosage of 0.75% of PECs on pulp, tensile strength was noticeably increased (+48%) and both compressive resistance Concora Medium Test (CMT) and Short-span Compressive Test (SCT) were markedly increased (+64% and +39%, respectively). These results suggest that PECs are a possible alternative to assist the application of LCMNF in papermaking.Fil: Schnell, Carla Natali. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Tarrés, Quim. Universidad de Girona; EspañaFil: Galván, María Verónica. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Mocchiutti, Paulina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Delgado Aguilar, Marc. Universidad de Girona; EspañaFil: Zanuttini, Miguel Angel Mario. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Mutjé, Pere. Universidad de Girona; Españ

Alkali-peroxide treatment of sugar cane bagasse : Effect of chemical charges on the efficiency of xylan isolation and susceptibility of bagasse to saccharification

Sugar cane is a promising raw material for the extraction of hemicelluloses. An alkali treatment of sugar cane bagasse under proper conditions followed by a precipitation using a reasonable quantity of ethanol can be an effective method to isolate these polysaccharides. In this work, bagasse is treated to obtain two products: (a) polymeric hemicellulose and (b) an enzymatic hydrolysate from the treated bagasse after hemicellulose extraction. The effects of charges of sodium hydroxide (10, 20, 40% w/w) and hydrogen peroxide (0, 10, 20% w/w) in the alkali treatment were evaluated. A 3² experimental design was considered under control of metal ions and inert atmosphere during alkaline treatment. An acceptable proportion of xylose plus arabinose could be extracted from bagasse (up to 18.4 g/100 g of bagasse). Both the alkali and peroxide showed strong effects on the yield of the extraction, as well as on the yield of the precipitation in ethanol-water solution. Besides, the susceptibility of bagasse for cellulolytic enzymatic hydrolysis is improved. The highest hemicellulose precipitation yield was 85% which corresponded to the treatment with the highest alkali charge without peroxide. The highest yield of enzymatic hydrolysis was obtained for the highest alkali and peroxide charges.Instituto de Fisiología VegetalInstituto de Botánica "Dr. Carlos Spegazzini

Upgrading OCC and Recycled Liner Pulps by Medium-consistency Ozone Treatment

Possibilities for improving the properties of old corrugated container (OCC) pulp by applying low levels of ozone at medium consistency were evaluated. In addition, pulps obtained from kraft liner and corrugating medium were considered. Ozone reduces the kappa number but the surface charge of the fiber is not changed. Ozonation clearly increases the relative bonded area (RBA) in sheets made from treated fibers. It was shown that RBA is essential for Concora medium test (CMT) resistance. Papermaking properties like tensile strength, internal bond strength, compression strength and CMT were significantly increased even at the lowest ozone charge employed. For OCC pulp, it is shown that similar improvements can be reached by refining and alkali treatment. Nevertheless, alkali has a greater effect on pulp freeness and produces a higher charge in the application. Properties like internal bond strength, compression strength and CMT of a recycled unbleached pulp can be notably increased by the application of low level of ozone.Fil: Zanuttini, Miguel Angel Mario. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Courchene, Charles. Instituto Tecnológico de Georgia; Estados UnidosFil: Mcdonough, Thomas. Instituto Tecnológico de Georgia; Estados UnidosFil: Mocchiutti, Paulina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Dual-polyelectrolyte adsorption of poly(allylamine hydrochloride) and xylan onto recycled unbleached kraft pulps

The effects of a double polyelectrolyte adsorption of poly(allylamine hydrochloride) (PAH) and xylan (Xyl) on a recycled unbleached softwood kraft pulp were studied. The kinetics of PAH adsorption on this pulp was analyzed by building adsorption isotherms and by estimating the surface nitrogen adsorbed through the X-ray photoelectron spectroscopy (XPS) technique. It was found that at pH 7.5, 0.01N NaCl, and short adsorption time, PAH is mainly adsorbed on the fiber surface. Adsorption isotherms of xylan on untreated and on previously PAH-treated pulps at different ionic strengths were built, and the effects of the amount of PAH on xylan adsorption were considered. It was found that when ionic strength was lower than 0.01N NaCl, a PAH pretreatment was necessary to achieve high levels of xylan adsorption at room temperature and short adsorption times. Nevertheless, when ionic strength was 0.1N NaCl, 0.3% xylan on pulp could be directly adsorbed on untreated pulp. Finally, it is shown that the dual-polyelectrolyte adsorption on this pulp is a feasible technique for improving paper tensile strength.Fil: Galván, María Verónica. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mocchiutti, Paulina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cornaglia, Laura Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Zanuttini, Miguel Angel Mario. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología Celulósica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin