Papers by Author: Maria José Geraldes

Abstract: In last decades, increased attention is paid to comfort properties of textiles and garments. The most important parameters characterizing the called physiological comfort of textile structures are the evaporative resistance and water vapour permeability. Contrary to common textiles, protective and functional garments and, also some technical textiles, are also used in wet state, which affect their comfort properties. In this paper, PERMETEST commercial instrument is described, which provide reliable non-destructive measurement of evaporative resistance and water vapour permeability of fabrics in dry and wet state. By means of this instrument, evaporative resistance and water vapour permeability of cotton, polyester and cotton/polyester knitting fabrics, in the wet state, were experimentally determined and results were discussed. The effect of count yarn and composition of the above mentioned properties of these fabrics has been investigated as well. Some surprising results were achieved: with increasing fabrics moisture, the water vapour permeability also increases, especially with the presence of hydrophilic textile material.

Abstract: Several factors affect the indoor air quality, among which ventilation, human occupancy, cleaning products, equipment and material; they might induce the presence of aerosols (or bioaerosols in the presence of biological components) nitrogen oxides, ozone, carbon monoxide and dioxide, volatile organic compounds, radon and microorganisms. Microbiological pollution involves hundreds of bacteria and fungi species that grow indoors under specific conditions of temperature and humidity. Exposure to microbial contaminants is clinically associated with allergies, asthma, immune responses and respiratory infections, such as Legionnaires Disease and Pontiac Feaver, which are due to contamination by Legionella pneumophila. Legionnaire's Disease has increased over the past decade, because of the use of central air conditioning. In places such as homes, kindergartens, nursing homes and hospitals, indoor air pollution affects population groups that are particularly vulnerable because of their health status or age, making indoor air pollution a public health issue of high importance. Therefore, the implementation of preventive measures, as the application of air filters, is fundamental. Currently, High Efficiency Particulate Air (HEPA) filters are the most used to capture microorganisms in ventilation, filtration and air conditioning systems; nevertheless, as they are not completely secure, new filters should be developed. This work aims to present how the efficiency of a textile nanostructure in a non-woven material based on synthetic textiles (high hydrophobic fibers) incorporating appropriate biocides to control Legionella pneumophila, is going to be measured. These bioactive structures, to be used in ventilation systems, as well as in respiratory protective equipment, will reduce the growth of microorganisms in the air through bactericidal or bacteriostatic action. The filter nanostructure should have good air permeability, since it has to guarantee minimum flows of fresh air for air exchange as well as acceptable indoor air quality.

Abstract: This work reports on research being carried out in the area of functional knitted fabrics with a special structure incorporating hydrophobic fibres near to the skin and suction channels of hydrophilic fibres to suck moisture from the skin on the hydrophilic layer away from the skin; in this way, comfort is maximised in active wear as the fabric does not feel wet near to the skin.

Abstract: This work reports on research being carried out in the area of functional knitted fabrics with a special structure incorporating hydrophobic fibres near to the skin and suction channels of hydrophilic fibres to suck moisture from the skin on the hydrophilic layer away from the skin; in this way, comfort is maximised in active wear as the fabric does not feel wet near to the skin.