Miloslav Milichovský

Surface Flocculation as a New Tool for Controlling Adsorption Processes

The dyeing of modified pulp, particularly with regard to the mechanism involved, was studied. The reaction mechanism for the modification of cellulose fibres in aqueous solution by cationic agents was also described. The results obtained were expressed in the form of adsorption isotherms. The capture of molecules, colloidal particles, etc. during the adsorption processes involving modified pulp could be explained by two possible mechanisms: (i) aggregation (coagulation or flocculation) in solution followed by adsorption and (ii) surface aggregation (coagulation or flocculation). Surface aggregation appeared to be the most likely for pulp with a low degree of modification. The typical Langmuir adsorption isotherm correlated the data obtained for unmodified pulp very well.

Adsorption Characteristics of Oxycellulose in a Competitive Environment with other Substances

A comparison was undertaken of the sorption response of oxycellulose and initial linters, i.e. the short fibres that adhere to cotton seed after ginning, towards Fe2+, Ca2+ and Cd2+ ions in fibrous slurries. The exceptional adsorption capability of oxycellulose towards metal ions (particularly Cd2+ ions) was confirmed. However, such adsorption processes are quite complicated and are influenced by the solubility of oxycellulose, its composition and the character of the components released into the supernatant, as well as by the presence of other competitive substances and ions in the aqueous solution. The adsorption capacity of oxycellulose increases with increasing –COOH group content and is distinctly increased by the presence of other competitive ions in the aqueous solution. Most probably, this enhanced adsorption capacity of the support bears some analogy to the superficial aggregation (flocculation) induced by the presence of foreign substances.

Kinetics of Vapour Diffusion and Condensation in Natural Porous Cellulosic Fibre Web

Vapour diffusion in a porous web material followed by its absorption or condensation is a typical process for all porous materials particularly on polymeric and natural basis. The description of kinetic weight increment increase during this process was proposed by use of a relatively simple function with adequately defined theoretical background. It was shown that this kinetic process is controlled by vapour diffusion through porous web material. This tool in connection with observations at different air relative humidity and with use of relatively simple technique enables one to evaluate the structure properties and its structure homogeneity, that is, the uniformity character of the porous stratified web material. Utilization of this description was demonstrated during moistening kinetics of paper web of different composition from primary and secondary fibres on lignocellulosic and only cellulosic basis with different ash content.

Impact of some Deacidification Means on the Changes of Selected Properties of Pulp

Deacidification is one of the basic restoration techniques to protect archival records stored in various depositories. This study examines the influence of selected deacidification aids on lignocellulose materials. Samples represent the commonly used pulps in the paper industry. These materials were treated with three deacidification methods in cooperation with National Archive in Prague. We monitored for changes as the optical, mechanical and chemical properties and changes on hypermolecular level. The results showed that the selected deacidification methods affect the surface-molecular and structural properties. The optical properties of the samples didn´t show any decrease of the ISO brightness and the colour coordinates L*a*b*. The values of surface pH were increased as expected. The mechanical properties of the samples was characterised by unitary stiffness, it was observed a significant sample stiffness decrease after treatment with the Bookkeeper and HERCO deacidification methods.

The Influence of Microbicidal Components of Essential Oils on the Properties of the Cellulose and Lignocellulose Materials

Biological effects of essential oils are investigated for many years. This work is focused on exploring the influence of saturated vapours components of essential oils on the mechanical, optical and chemical properties of cellulose and lignocellulose materials. Diluted vapours of active ingredients of essential oils could be used in future to protect archives made of cellulose materials. For testing were chosen ingredients of essential oils, that showed the highest bactericidal activity. Saturated vapours of these components act on selected cellulose and lignocellulose materials for a predetermined time. From the mechanical properties were measured tensile strength, bending stiffness and compressive strength. Optical properties are represented by the colour difference ∆E and chemical properties by pH change.

Effect of Essential Oils on the Mechanical Properties of Lignocellulosic Materials

Biodeterioration of lignocellulosic materials is a worldwide problem and it causes a great damage especially to unique manuscripts and books stored in libraries. These materials are permanently subject to suffering from physical, chemical, and/or biological changes. Biological deterioration by microorganisms (bacteria and fungi) causes undesirable changes on material properties. Paper made by vegetal fibers, functional additives (glue, optical polishers, consolidating nts), and inks with organic bindings are used as sources of nutrients. Using of EOs (essential oils) for protection against microorganisms appears to be an option, because antimicrobial effects of the main compounds of EOs were proven. This work analyzes the antimicrobial stability of 2 essential oils (citral and linalyl acetate), as well as their stability of mechanical properties, in selected lignocellulosic materials (soft wood and hard wood kraft pulp, softwood sulphite pulp). Some parts of samples were subjected only to the condition of the EOs, other samples were firstly treated by accelerated ageing. Last samples were exposed to the accelerated ageing and afterwards treated by EOs. From the mechanical properties measuring of samples it is possible to state that in some SAJ samples the influence of EOs vapour is positive. This was monitored even when the samples were treated by accelerated ageing.