Jan Broda

Influence of pigments on supermolecular structure of polypropylene fibres

Abstract WAXS and DSC investigations of the structure of uncoloured and coloured polypropylene fibres were carried out. Two organic pigments: a phthalocyanine and a quinacridone with different nucleating abilities were used for the colouring of fibres. The fibres were formed at various take-up velocities, and heat stabilized at temperature in the range 120–160°C. It was stated, that two polymorphic forms α and β occur in uncoloured fibres spun at extrusion velocity. Fibres spun at small and medium take–up velocity contain the mesophase, whereas fibres spun at high take-up velocity contain the crystalline α-form. In the fibres coloured with a phthalocyanine the α-form occurs independently of the take-up velocity. Fibres coloured with a quinacridone contain both forms α and β. A great content of β-form occurs in fibres spun at the lowest take-up velocity. The observed changes of the structure of fibres are connected with the change of nucleation mechanism. During heat stabilization perfecting of α-form occurs. The mesophase and a hexagonal β-form transform into a monoclinic α-form. The degree of transformation depends on the stabilization temperature. For coloured fibres the structure of unstabilized fibres is more perfect and undergoes smaller changes during stabilization than the structure of uncoloured fibres.

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.

Formation and properties of polypropylene/stearic acid composite fibers

This paper refers to the formation and properties of polypropylene/stearic acid (PP/SA) composite fibers. For the investigation, commercial metallocene-catalyzed PP polymer and SA were used. The fibers were produced in laboratory conditions using the single screw spin draw device. The textile-mechanical properties, surface composition, morphology and supermolecular structure of as-spun fibers were studied. Moreover, the nonisothermal crystallization of the PP/SA blend and melting behavior of fibers were analyzed. In the investigation Fourier transform infrared–attenuated total reflectance, scanning electron microscopy, differential scanning calorimetry and wide-angle X-ray analytical methods were used. The research showed that the PP/SA blend has lower viscosity compared to the pure polymer and that during the PP crystallization phase, separation is induced. SA delays crystallization of PP, and interaction between SA and PP is observed. The as-spun PP/SA fibers have higher linear density, higher elongation at break and slightly lower tenacity compared to fibers produced from pure PP. The fibers contain a structure with high content of mesophase. During fiber formation, SA migrates towards the fiber surface and forms droplets located beneath the surface of the fiber or crystallizes outside in the form of flake-like crystals.

Influence of heat‐stabilization on supermolecular structure of colored PP fibers

Investigations of supermolecular structure and tensile properties of colored heat-stabilized fibers were carried out. For fiber coloring, chosen organic pigments with differentiated nucleating properties were used. It was stated that during the fiber formation, a fibrillar–lamellar structure with α-crystals is formed. In fibers colored with a quinacridone pigment, the minimal number of β-crystals was observed. During heat-stabilization, perfecting of the supermolecular structure of the fiber occurs. Because of pigments, the process of rebuilding occurs more intensively and leads to formation of a more stable structure with higher crystallinity.

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.

Crystalline and Lamellar Structure of Polypropylene Fibrillated Fibres

The effects of processing conditions on the structure of polypropylene fibrillated fibres were studied using a combination of wide- and small-angle X-ray scattering methods. In particular the impact of selected stages of processing on the crystalline and lamellar structure of PP were analyzed. It was stated that crystalline phase is built from α crystals. The crystallinity index as well as the Herman orientation factor of the crystalline phase is found to have a correlation only with the draw ratio of the PP film. The lamellar structure also changes with the draw ratio.