Monika Rom

In vitro and in vivo studies on biocompatibility of carbon fibres

In the present study we focused on the in vitro and in vivo evaluation of two types of carbon fibres (CFs): hydroxyapatite modified carbon fibres and porous carbon fibres. Porous CFs used as scaffold for tissues regeneration could simultaneously serve as a support for drug delivery or biologically active agents which would stimulate the tissue growth; while addition of nanohydroxyapatite to CFs precursor can modify their biological properties (such as bioactivity) without subsequent surface modifications, making the process cost and time effective. Presented results indicated that fibre modification with HAp promoted formation of apatite on the fibre surface during incubation in simulated body fluid. The materials biocompatibility was determined by culturing human osteoblast-like cells of the line MG 63 in contact with both types of CFs. Both tested materials gave good support to adhesion and growth of bone-derived cells. Materials were implanted into the skeletal rat muscle and a comparative analysis of tissue reaction to the presence of the two types of CFs was done. Activities of marker metabolic enzymes: cytochrome c oxidase (CCO) and acid phosphatase were examined to estimate the effect of implants on the metabolic state of surrounding tissues. Presented results evidence the biocompatibility of porous CFs and activity that stimulates the growth of connective tissues. In case of CFs modified with hydroxyapatite the time of inflammatory reaction was shorter than in case of traditional CFs.

Innovative wool geotextiles designed for erosion protection

Innovative geotextiles built from meandrically arranged thick ropes were produced. For the production of the geotextiles, the strips of woollen nonwoven were used. The segments of the geotextiles were installed on the bank of a drainage ditch. The behaviour of the geotextiles during 1 year was observed. It was demonstrated that the geotextiles installed in the ditch provide immediate protection of the bank. In the soil-covered wool, the process of slow biodegradation was initiated. Because of a low biodegradation rate at the end of the growing season, when the protective vegetation was not well developed, the geotextiles maintained their protective potential. In the following months, the biodegradation led to further destruction of wool fibres. During the biodegradation, the organic compounds rich in nitrogen were released into the soil. In spring, at the beginning of new growing season, the compounds acted as effective fertilizers, promoting the growth of protective vegetation. The vegetation growing on the bank provided an effective protection and took over the protective function of the geotextiles.

Biodegradation of Wool Used for the Production of Innovative Geotextiles Designed to Erosion Control

Sheep wool was used for the production of innovative geotextiles designed to erosion control. The Kemafil ropes filled with wool, which are used for the production of geotextiles were buried in the ground. During ground disposal the susceptibility of wool to biodegradation was observed. The basic geometrical and mechanical parameters of wool fibres as well as their chemical composition and the surface morphology were analysed. It was observed that the ground disposal causes the decrease of breaking force of fibres and the destruction of scales on their surface. Within four months the biodegradation reaches the first stage consisting in cleavage of disulfide bonds of keratin. The rapid biodegradation is observed in fibres mechanically damaged. In the presence of the hydrogel the biodegradation is delayed. After four months, despite observed biodegradation of wool, the ropes maintain their ability to fulfil the erosion protection function.

Effect of Enzymatic Treatment on Solubility of Cellulose in 7.6%NaOH-Water and Ionic Liquid

The effect of enzymatic pretreatment on the properties of cellulose dissolved in aqueous 7.6%NaOH and in an ionic liquid (IL) was investigated and compared with viscose prepared from the same raw material and dissolved in 7.6%NaOH. The enzymatic pretreatment decreased by twice the DP of cellulose as compared with the initial one. This facilitated cellulose dissolution in NaOH. The flow of enzyme-treated pulp dissolved in 7.6%NaOH-water and in IL was studied and compared with cellulose xanthate dissolved in aqueous 4.5%NaOH-water. The solutions of enzyme-treated cellulose in NaOH-water gelled with heating in the same way as non-treated cellulose solutions. The dependence of the intrinsic viscosity as a function of temperature of the enzyme-treated cellulose dissolved in 7.6%NaOH showed the same trend and similar values as for microcrystalline cellulose dissolved in this solvent. The assumed presence of insoluble material in cellulose-NaOH solution was proved by flow cytometry, which indicated an average particle diameter of the insoluble or swollen entities being around 600 nm. Cellulose beads were prepared from NaOH-water solutions of enzyme-treated pulp and of viscose. SEM images showed that their surface topography was dependent on cellulose treatment. It was shown that the enzyme-treated pulp-NaOH-water system could be used for bead manufacturing.

Formation of the Porous Polyaniline Structures

The conductivity of polyaniline can be controlled depending on the doping mechanism. Porosity of polyaniline seems to be one of the important factors of solid state doping, and depends on several synthesis process parameters as well as subsequent refining steps. Results of studies on polyaniline refinement with common solvents: methanol, chloroform, DMF and THF are presented. The effect of solvent type used for extraction on the polyaniline porosity is discussed.

Utilisation of textile wastes for the production of geotextiles designed for erosion protection

Abstract Textile waste was used for production of thick ropes designed for the protection of slopes against sliding and erosion. For the production of ropes, scraps of insulating materials produced from poor quality wool and scraps of nonwoven manufactured from blend of recycled fibres were applied. The ropes were installed on the slope in a disused gravel pit. Stabilisation of the slope and behaviour of the materials used were analysed during two vegetation seasons. Investigations confirmed the usefulness of the technology for the protection of steep slopes.

Study of Structure of Polypropylene Microfibres Modified with Multi-Walled Carbon Nanotubes

The paper presented is concerned with studies of a supermolecular structure and its transformation during the process of drawing new composite microfibres obtained from isotactic polypropylene (iPP) – as a matrix and multi-walled carbon nanotubes (MWCNT) used as the filler. The nanostructure of iPP/MWCNT microfibres as spun and after drawing at a temperature of 95°C was investigated using scanning electron microscopy (SEM), wide angle X-ray scattering (WAXS), small angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) methods.