Improving the Mould and Blue-Stain-Resistance of Bamboo through Acidic Hydrolysis

Bamboo is much more easily attacked by fungus compared with wood, resulting in shorter service life and higher loss in storage and transportation. It has been long accepted that the high content of starch and sugars in bamboo is mainly responsible for its low mould resistance. In this paper, acetic acid, propionic acid, oxalic acid, citric acid, and hydrochloric acid were adopted to hydrothermally hydrolyze the starch in bamboo, with the aims to investigate their respective effect on the mould and blue-stain resistance of bamboo, and the optimized citric acid in different concentrations were studied. The starch content, glucose yields, weight loss, and colour changes of solid bamboo caused by the different acidic hydrolysis were also compared. The results indicated that weak acidic hydrolysis treatment was capable of improving mould-resistant of bamboo. The mould resistance increased with the increased concentration of citric acid. Bamboo treated with citric acid in the concentration of 10% could reduce the infected area ranging to 10–17%, the growth rating of which could reach 1 resistance. The content of soluble sugar and starch remained in bamboo decreased significantly from 43 mg/g to 31 mg/g and 46 mg/g to 23 mg/g, respectively, when the citric acid concentration varied from 4% to 10%. Citric acid treatments of 10% also caused a greatest surface colour change and weight loss. The results in this study demonstrated citric acid treatment can effectively reduce the starch grain and soluble sugars content and improve mould resistance of bamboo, which can be attributed to the reduction of starch grain and soluble carbohydrates (such as glucose, fructose, and sucrose, etc.) in bamboo.

Validation of Antibacterial Systems for Sustainable Ceramic Tiles

Ceramic tiles are bacteriostatic materials; however, the COVID-19 emergency has pushed tile producers to improve surfaces’ antibacterial properties. The aim of this work was to validate a silver-based antibacterial treatment applied to porcelain stoneware tiles based on natural and waste materials, thus correlating surface functionalization to tile composition and relevant physical, microstructural, and textural parameters. The treatment was applied before firing, with and without a polymeric primer. Antibacterial activity tests, stain resistance tests, and contact angle measurements were carried out on fired tiles. Further investigations were made by SEM and optical profilometry in order to study the morphological–structural profile of tile surfaces. Results showed strong antibacterial activities for all the functionalized tiles, which were mainly correlated to the morphological and textural parameters of ceramic surfaces, as well as the presence of the polymeric primer.

Comparative study on design and functionality requirements for senior-friendly furniture for sitting

Furniture manufacturers’ response to the demographic challenge of aging nations is an important issue. The number of seniors is rising worldwide. The aging process often results in multiple health implications, including weaker mobility, decrease in muscle mass, and change in anthropometrical dimensions of the human body. Thus, the furniture offered should be adjusted to the needs of an increasing group of senior customers. To identify seniors’ preferences in relation to characteristics of sitting furniture, international surveys with 627 respondents aged 60+ years were conducted in Poland, Germany, Denmark, Finland, Latvia, and Lithuania. The implementation of this data in the design process may result in creation of the market offer meeting seniors’ needs. Design and functionality features were examined to provide guidance for senior-friendly development of furniture for sitting. Among the most important findings is the clear preference of having an armchair with the high backrest reaching above the head, a chair with armrests and an upholstered backrest and seat. Furthermore, respondents paid attention to the durability of furniture, stain resistance of upholstery, and adaptation of the furniture to the user’s dimensions, e.g., having influence on the height and depth of the seat before the purchase.

An Experimental Study for the Improvement of the Stain Resistance for Exterior Wall Paints in a Western City in China

In recent years, with the rapid development of the building industry in western cities during the period of “Western Development” in China, the paints industry has developed rapidly and become more mature. In addition, waterborne inorganic exterior wall paints have been a great choice in the building industry because of their reduced volatile organic compounds (VOCs) and less toxicity and odor. However, the problem of stain resistance for exterior wall paints in western cities has not been solved, which has become a major obstacle to the application and promotion of exterior wall paints in western cities in China. Therefore, effective measures should eventually be carried out for improving the stain resistance of exterior wall paints in western cities in China. In this paper, an experimental study on improving stain resistance for exterior wall paints in a typical western city in China, Chongqing, is reported. In the three defined designs, the effects of the paint structure type, the pigment volume concentration (PVC), thickeners, cosolvents and wetting and dispersing agents on the stain resistance of exterior wall paints in a typical western city in China, Chongqing, were examined. The experimental results suggest that the stain resistance of silicone–acrylic paint was the most suitable among the three kinds of tested paints (silicone–acrylic paint, styrene–acrylic paint and pure acrylic paint). In addition, the PVC had a great influence on the stain resistance of the exterior wall paints. The compactness, water absorption and stain resistance of the paint’s film were the most suitable when the PVCs of the paints reached 45%. Furthermore, the tested wetting and dispersing agents made the same contributions to the paints’ stain resistance, as their decline rates for reflectivity were similar. The reflectivity of the film significantly decreased when the ratio of associating thickener to non-associating thickener reached 4:1, and also significantly declined when the content of propylene glycol reached 5%.

Improving the technology of repair painting with powder-coated paints in agro-industrial complex

The article presents the results of studies to determine the dependence of the degree of adhesion and the separation force of the powder coatings layer on the roughness parameter of the substrate, as well as the contact angle of wetting for various methods of preparing the painted surface by chemical methods. In addition, practical tests for stain resistance were carried out, which showed the absence of corrosion damage, as well as a slight change in color, gloss of coatings, chalking and dirt retention on the studied coating samples.

Study on Preparation of PA6 / PDMS Blended Fibers and Fabric Properties

PA6 fibers and fabric properties were studied by adding PDMS, and PA6 / PDMS blend fibers were prepared by melt spinning. The experiment found that the addition of PDMS can significantly promote the rheology of the PET / PDMS blend melt. DSC tests show that the addition of PDMS has basically no effect on its crystallization and melting characteristics. With the increase of PDMS content, the contact angle of water on the blended fabric surface increased. KES-FB was used to evaluate fabrics made from PA6 / PDMS blended fibers. It was found that with the increase of PDMS content, the softness and elasticity of the fabrics were improved, and the stain resistance experiments showed that the modified fabrics had good resistance dirty performance.