Evaluation of Thermal Properties of Certain Flame-Retardant Fabrics Modified with a Magnetron Sputtering Method

Abstract

The article presents the modification of flame-retardant fabric surfaces made of basalt, Nomex®, and cotton fabric to improve their selected thermal comfort properties. The modification consisted of depositing on the fabric surface by magnetron sputtering the metal (aluminum) and ceramic (zirconium (IV) oxide) coatings with a thickness of 1 μm and 5 μm. Flame-retardant fabrics have been chosen because of the desire to apply them to gloves intended for the use in hot-work environments. The article presents the results of testing reference samples and their modifications, which were subjected to the test of resistance to contact heat for contact temperatures of 100°C and 250°C, resistance to thermal radiation and examined their selected thermal comfort parameters, i.e., the thermal conductivity coefficient and heat absorption coefficient. Almost the 1st efficiency level for contact heat was reached for basalt fabric coated with zirconium (IV) oxide with a thickness of 5 μm. The 1st level of protection against heat radiation was obtained for all reference and modified samples. Based on the Kruskal–Wallis test, it was noticed that a significant change in parameter values is caused by the modification with 5 μm thick coating.

Assessment of Coating Quality Obtained on Flame-Retardant Fabrics by a Magnetron Sputtering Method

“…The chosen textile substrates were coated with aluminum or zirconium (IV) oxide with a thickness of 5 µm. An assessment of resistance to contact heat based on the threshold time t 100 and resistance to radiant heat based on the relative heat transfer index RHTI 24 was conducted [ 22 ] and presented in Table 3 . Measurements were repeated three times.…”

“…Three flame-retardant twill weave fabrics were selected for testing [22]: Basalt fibers are flame-retardant. Fabrics made of basalt fibers can be used as materials to protect against fire and heat.…”

“…The following designation was used for unmodified and modified fabrics: Aluminum or zirconium (IV) oxide coatings of 5 µm thickness were deposited on only one side of the selected fabrics. The Al and ZrO 2 coatings were chosen because they improved the thermal properties of textile substrates in previous research [22].…”

“…Three flame-retardant twill weave fabrics were selected for testing [ 22 ]: Basalt fabric (100% basalt fibers) with a thickness of 0.55 mm and surface mass of 398 g/m 2 ; Nomex ® fabric (93% m-aramid, 5% p-aramid, and 2% antistatic fibers P140) with a thickness of 0.37 mm and surface mass of 266 g/m 2 ; and Cotton fabric with the flame-retardant finish (100% cotton fibers) and a thickness of 0.66 mm and surface mass of 376 g/m 2 . …”

“…The main aim of the study is to assess the quality of coating deposited on the basalt fabric, Nomex ® fabric, and cotton fabric, with the flame-retardant finishing, using the magnetron sputtering method. A coating of 5 µm thickness was deposited on the surface of selected fabrics, due to a statistical analysis showing that the assumed thickness is preferred [ 22 ]. The evenly coated fabric ensures that there are no places on the sample surface where the values of thermal parameters such as the resistance to contact heat and resistance to radiant heat deviate significantly from the specified ones.…”