OBTAINING MICROCRYSTALLINE CELLULOSE FROM SOFTWOOD AND HARDWOOD PULP

Conditions for obtaining microcrystalline cellulose (MCC) by the thermocatalytic method from hardwood (birch, aspen) and softwood (pine) bleached sulphate pulp have been developed. After thermocatalytic treatment, cellulose polymerization degree has decreased to the so-called levelling-off degree of polymerization (LODP), which, in the case of birch, aspen and pine wood pulp, made up 450, 370 and 250 units, respectively. After grinding the destructed pulp in a ball mill, MCC powder samples were obtained with particles, the major part of which had sizes of 2-20 m. In terms of physico-chemical indices investigated in this work, the obtained samples conform to the pharmacopoeia requirements. Dispersing the destructed pulp in water medium, at a sufficiently high cellulose concentration ( 8%), MCC gel samples were prepared, with rheological properties typical for liquid crystalline polymers. The indices of the obtained hardwood and softwood MCC were compared

Use of Cellulose-Containing Fillers in Composites with Polypropylene

The composites, containing recycled polypropylene and fillers, obtained from different lignocellulosics by the thermocatalytic destruction method, were investigated. Birch sawdust, newsprint wastes, cotton residues and wood bleached sulphate pulp were used as raw materials for obtaining fillers. The indices of mechanical properties (tensile strength, modulus of elasticity, deformation at break, shear modulus, toughness, twisting moment) of the composites' samples were determined. It has been found that the obtained composites have relatively good mechanical properties. Better results were obtained, using fillers from sawdust and wood pulp. After treating the fillers with rapeseed oil, their water vapour sorption and water retention value (WRV) decreased. In this case, the strength of the composites was higher.http://dx.doi.org/10.5755/j01.ms.17.2.484</p

Highly loaded cellulose/poly (butylene succinate) sustainable composites for woody-like advanced materials application

We report the manufacturing and characterization of poly (butylene succinate) (PBS) and micro cellulose (MCC) woody-like composites. These composites can be applied as a sustainable woody-like composite alternative to conventional fossil polymer-based wood-plastic composites (WPC). The PBS/MCC composites were prepared by using a melt blending of 70 wt% of MCC processed from bleached softwood. MCC was modified to enhance dispersion and compatibility by way of carbodiimide (CDI), polyhydroxy amides (PHA), alkyl ester (EST), (3-Aminopropyl) trimethoxysilane (APTMS), maleic acid anhydride (MAH), and polymeric diphenylmethane diisocyanate (PMDI). The addition of filler into PBS led to a 4.5-fold improvement of Young’s modulus E for the MCC composite, in comparison to neat PBS. The 1.6-fold increase of E was obtained for CDI modified composition in comparison to the unmodified MCC composite. At room temperature, the storage modulus E′ was found to improve by almost 4-fold for the APTMS composite. The EST composite showed a pronounced enhancement in viscoelasticity properties due to the introduction of flexible long alkyl chains in comparison to other compositions. The glass transition temperature was directly affected by the composition and its value was −15 °C for PBS, −30 °C for EST, and −10 °C for MAH composites. FTIR indicated the generation of strong bonding between the polymer and cellulose components in the composite. Scanning electron microscopy analysis evidenced the agglomeration of the MCC in the PBS/MCC composites. PMDI, APTMS, and CDI composites were characterized by the uniform dispersion of MCC particles and a decrease of polymer crystallinity. MCC chemical modification induced the enhancement of the thermal stability of MCC composites

Blends of PVA with Natural Fillers

Several blends of polyvinyl alcohol, glycerol and natural fillers (starch, thermocell and thermocell gel) have been prepared. The influence of fillers in blend systems on the mechanical and thermal properties and biodegradation in soil of the prepared films was investigated. It was found that mechanical characteristics, thermal properties and biodegradation of modified PVA films were significantly affected by content and correlation of fillers. Tensile strength and elongation at break of irradiated modified PVA films decreased but for clean PVA films mentioned tensile strength increased ~2.5 times. Addition of biodegradable natural filler thermocell gel facilitates the biodegradation of PVA films in soil

PVA Based Composites with Natural Fillers

Poly (vinyl alcohol) (PVA) is recognized as one of the very few vinyl polymers soluble in water also susceptible of ultimate biodegradation in the presence of suitably acclimated microorganisms. Accordingly, increasing attention is devoted to the preparation of environmentally compatible PVA-based materials for a wide range of applications. Several composite blends based on PVA (0.8-2.0 wt% acetate groups) were prepared and characterized

Effect of chitosan on properties of paper for packaging

International audienceThe effect of chitosan additives on the mechanical and hydrophobic properties, and air permeability of paper sheets was investigated. As chitosan additives, molecular chitosan and nanochitosan were used. Molecular chitosan was obtained by dissolving chitosan in 1% acetic acid. Nanochitosan was obtained using a thermocatalytic destruction method. It has been established that chitosan additives improve the mechanical properties of paper sheets (tensile strength in dry and wet states, burst strength). In the case of molecular chitosan, tensile index in dry and wet states increases with increasing chitosan dosage till 2.5-3.0% and then remains constant. It can be explained by the fact that chitosan forms ionic bonds and polyelectrolyte complexes with hemicelluloses and cellulose. At the dosage of 2.5-3.0%, all possible ionic bonds are already formed and further chitosan can form only hydrogen bonds by amino groups with cellulose. In the case of micro-nanochitosan, micro-nanoparticles fill also the submicroscopic voids in the porous structure of paper and create additional bonds. Chitosan additives also improve the hydrophobic properties (decrease of water adsorption, and increase of wetting time) and air permeability of paper sheets