Enhanced Hydrophobicity of Polymers for Protective Gloves Achieved by Geometric, Chemical and Plasma-Surface Modification.

Gloves are one of the most important elements of personal protective equipment (PPE). To improve gloves properties, a lot of different methods of surface modifications are used. In this work, the application of geometric, chemical, and plasma surface modifications to improve the hydrophobicity of butyl (IIR) and silicone (MVQ) rubber are described. To characterise surface properties contact angle measurements, FT-IR spectroscopy and scanning electron microscopy were used. This study showed that when the chemical modification applied, the contact angle value increases compared to non-modified samples. In addition, plasma modification raised the contact angle value and smoothed the surface morphology. An increase in the polymer surfaces hydrophobicity was the observed effect of the three modifications of rubber.

Use of Ashes from Lignite Combustion as Fillers in Rubber Mixtures to Reduce VOC Emissions.

This paper presents the use of ashes from brown coal combustion (BCA) as fillers in rubber mixtures, to reduce the emission of volatile organic compounds. Two types of ash, BCA1 and BCA2, were selected as fillers for styrene-butadiene rubber (SBR). The ashes were produced during the treatment of brown coal at the Belchatów Power Plant in the years 2017 and 2018. The morphology and chemical composition of the ash were tested. Morphology studies using scanning microscopy showed differences in the grain sizes of the ashes, and EDS analysis showed a difference in their chemical compositions. Vulcanizates with different weight proportions of the individual ashes were produced. Mixtures were made with the addition of 10-30 pts. wt. ashes per 100 g of SBR. The addition of BCA1 ash at 10 and 30 pts. wt. reduced the emission of volatile organic compounds (VOC) while maintaining the good strength properties of the mixtures.

Preliminary Research: Validation of the Method of Evaluating Resistance to Surface Wetting with Liquid of Protective Materials Intended for Polymer Protective Gloves.

The article presents validation argumentation of the novel method of evaluating resistance to surface wetting with different liquids of protective materials intended for polymer protective gloves based on the three parameters: water permeability index, non-wettability index and absorption index. Using our own method of evaluating resistance to surface wetting, it was shown that the knurled structure of the palm part of polymer protective gloves may inhibit transport of harmful and hazardous liquids outside the area of the protective glove. Currently, there is lack of objectifying methods for evaluation of surface wettability focused on the mentioned aspects. In view of the above facts, an original method for evaluating the resistance of protective materials to surface wetting with mineral oils and water has been invented and validated. It was assumed that the non-wettability index will be subjected to metrological analysis. Consequently, the validation process refers to this index. A precise assessment of the uncertainty budget of the individual components was obtained. On the basis of the obtained results, the measurement errors that may affect the quality and reliability of the test result performed in the laboratory were identified.

The Influence of the Size and Oxidation Degree of Graphene Flakes on the Process of Creating 3D Structures during its Cross-Linking.

This article presents the results of the cross-linking of oxidized flake graphene (GO) using hydrazine at room temperature. Conducting the process at temperatures up to 30 °C allowed to eliminate the phenomenon of thermal GO reduction to its non-oxidized form. In addition, based on the Infrared and Raman spectroscopy as well as X-ray photoelectron spectroscopy (XPS) analysis, the cross-linking ability of GO was observed depending on its size and degree of oxidation. These parameters were associated with selected physicochemical and electrical properties of obtained 3D structures. Three GO flakes sizes were tested in three different oxidation degrees. It was shown that, regardless of the size of GO, it is crucial to achieve a specific oxidation degree threshold which for the conducted tests was a >20% share of oxygen atoms in the whole structure. This value determines the ability to cross-link with hydrazine thanks to which it is possible to synthesize the spatial structure in which the π-π interactions among individual flakes are significantly reduced. This directly translates into the fact that the 3D structure shows an electrical resistance value in the range of 4-103 Ω, depending on the size and oxidation degree of the used material. The explanation of this phenomenon related to the electrical conductivity of 3D structures was confirmed based on the molecular modeling of the chemical structures.