Andrej Demšar

Influence of N-, P- and Si-based Flame Retardant Mixtures on Flammability, Thermal Behavior and Mechanical Properties of PA6 Composite Fibers

This research investigated the influence of two flame retardant (FR) mixtures consisting melamine cyanurate (MeCy) and aluminum diethylphosphinate (AlPi), and MeCy and sodium aluminosilicate (SASi) at different weight ratios, on the flammability, thermal behavior and mechanical properties of polyamide 6 (PA6) composite yarns produced by meltspinning. The morphological and chemical properties of PA6/FR filaments were investigated by scanning electron microscopy and Fourier-transform infrared spectroscopy, flame retardancy by vertical burning test UL-94, thermal behavior by thermogravimetric and differential scanning calorimetric analyses, and mechanical properties by tensile tests. The results indicate that within the UL 94 V2 rating, the composite yarns differed significantly from each other in their burning and dripping behavior. The incorporation of both mixtures, MeCy+AlPi and MeCy+SASi, into the PA6/FR yarns significantly decreased the afterflame time relative to pristine PA6, confirming a lower production of flammable volatiles. This phenomenon was attributed mainly to MeCy, which caused an immediate extinguishment of the flame after the withdrawal of the igniting flame. Compared to one component MeCy, the incorporation of the MeCy+SASi mixture enhanced the thermooxidative stability of the PA6/FR yarns because of their additive effect at higher concentrations. In contrast, an antagonistic effect was obtained for the MeCy+AlPi mixture, irrespective of the concentration. Since the incorporation of MeCy+SASi did not drastically reduce the tensile properties of filaments, this mixture enables the production of the PA6/MeCy+SASi composite yarns with the enhanced flame retardancy and thermo-oxidative stability.

FT-Raman Analysis of Cellulose based Museum Textiles: Comparison of Objects Infected and Non-infected by Fungi

It is well-known fact that the supermolecular structure of museum textiles changes during aging and biodeterioration. These structural changes can be observed by diff erent spectroscopic methods such as FT-IR, FT-Raman, and dispersive Raman spectroscopy. The purpose of the presented research is to present the usability of FT-Raman spectroscopy method for the analysis of the cellulose structure of the biodeteriorated historical textile fi bers. Although historical textiles have already been analyzed using FT-Raman spectroscopy the method has been rarely used to analyze the changes of supermolecular structure of the biodeteriorated historical textiles attacked by microorganisms. In the research, cellulose textile samples from diff erent museums and religious institutions were analyzed. Contemporary and historical cellulose textiles were scanned by FT-Raman spectra of reference and compared to determine the supermolecular cellulose fi ber structure of each material. It has been shown that structural changes such as depolymerization and crystallinity changes can be detected using FT-Raman spectroscopy. The supermolecular changes of the cellulose fi ber structure have been detected in biodeteriorated as well as in historical objects not infected by microorganisms. In the spectra of biodeteriorated objects, more intensive changes of spectral features were observed compared to spectra of non-infected samples. The changes were more pronounced at the museum objects made of fl ax. It can be concluded that biodeterioration causes more intensive structural changes than aging. On the basis of the research work, it has been shown that FT-Raman spectroscopy method can be used for the analysis of supermolecular structure changes of cellulose textiles.

Investigation of the Characteristics of Elasticised Woven Fabric by Using PBT Filament Yarns

Abstract Owing to growing demand for comfortable clothes, elastane filament yarns are being used in fabrics for several garments. In this study, core spun yarns were produced with cotton fibres and PBT/elastane filament yarns (cotton as sheath material, PBT yarn and elastane as core yarns). Twill woven (1/3 Z) fabrics were produced by using core spun yarns (30 tex) and cotton yarns (30 tex) as weft, and 100% cotton yarn (59 tex) as warp yarns. The fabrics consisting of PBT were washed at 100°C for 30 minutes to gain the elasticity. The woven fabrics’ weight, thickness, elongation, permanent elongation, dimensional stability, air permeability, thermal conductivity, thermal absorptivity characteristics were tested and statistically evaluated. According to the results, the fabrics containing PBT and elastane filaments had similar elongation and shrinkage values. PBT filament yarns have a great potential to produce lightweight elastic fabrics.