Search

Due to the prevalence of the COVID-19 pandemic, the demand for disposable facemasks has become a global issue. Unfortunately, the use of these products has negative effects on the environment, and therefore, the use of biodegradable materials is a powerful strategy to overcome this challenge. Aligned with this concept, in this work, biodegradable facemasks were developed using poly(ε-caprolactone) (PCL) polymer and cotton natural fibers. The filter layer was produced using an electrospinning technique, since electrospun membranes present remarkable characteristics for air filtration. The electrospun membranes were functionalized with different nanoparticles (NPs), including silver (Ag), titanium dioxide (TiO2) and magnesium oxide (MgO), in order to include new properties, namely antibacterial effect. The developed membranes were characterized by FESEM, EDS, ATR-FTIR, GSDR and TGA, which confirmed the successful impregnation of NPs onto PCL membranes. The antibacterial effect and filtration efficiency were assessed, with the PCL/MgO NPs membrane presenting better results, showing inhibition zone diameters of 25.3 and 13.5 mm against Gram-positive and Gram-negative bacteria, respectively, and filtration efficiency of 99.4%. Three facemask prototypes were developed, and their filtration efficiency, air permeability and thermal comfort were evaluated. Overall, this study demonstrates the potential of PCL/NPs electrospun membranes to act as an active and biodegradable filter layer in facemasks. [ABSTRACT FROM AUTHOR]

Pigments from natural sources, such as bacterial pigments, have gained increased attention in recent years due to their biodegradability, non-toxicity, and noncarcinogenicity. The intention to replace synthetic and oil-derived compounds is not restricted to synthetic dyes; other applications include the replacement of oilderived polymers for more environmentally friendly options, such as biopolymers. In this work, the functionalization of a bacterial cellulose (BC) biopolymer with bacterial pigments was explored using a full factorial design methodology to evaluate the best functionalization conditions to produce colored BC. From the factors and interactions evaluated, it was possible to conclude that the variable duration of the functionalization procedure could be reduced to a low level without significantly affecting the functionalization of the BC samples with bacterial pigments. Moreover, BC is a product with high industrial applicability, versatility, and sustainability. Hence, the multifunctional colored BC can be applied in the packaging, paper, and textile industries, among others. [ABSTRACT FROM AUTHOR]

Composite wound dressings which combine the suitable properties of distinct materials into one dressing are currently being explored, in combination with different types of bioactive compounds, to enhance the healing process and avoid skin infections. In the present work, poly(vinyl alcohol) and chitosan nanofibers containing Agrimonia eupatoria L. were fabricated using a needleless electrospinning method (through Nanospider technology) and deposited on top of a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cotton textile dressing. The negatively charged carboxyl groups on the cotton fibers interacted with the positively charged amino groups of chitosan, which was previously blended with poly(vinyl alcohol) and Agrimonia eupatoria L. to produce the nanofiber layer. The properties of the produced composite materials were analyzed to determine the dressing's potential for antimicrobial wound dressing applications. [ABSTRACT FROM AUTHOR]

The objective of this study is to analyze the impact behavior on the basis of energy approach of weft knitted structures, namely a jersey composite and an auxetic composite using high performance yarns. Weft knitted fabrics were produced with the same structural and machine parameters, using 100% para-aramid and hybrid (47% para-aramid and 53% polyamide) structure. Composite fabrication was achieved through hand lay-up using epoxy resin. Negative Poisson ratio of the reinforcing auxetic fabric was transferred from the fabric to the composite developed. Results obtained by drop weight dart impact test show that the impact experiment with different impact loads confirmed the auxetic composites, regardless de material composition, have an increase in the total energy absorption compared to jersey reinforced composite, approximately 2.5 and 4 times more for para-aramid and hybrid composite, respectively. Auxetic composites developed within this work present great potential for applications in different areas, mainly where energy absorption is a key factor to be considered, such as in protection, sports among others. [ABSTRACT FROM AUTHOR]

The removal of agriculture residual plastic films is nowadays a big concern for all environmentalists. Several ecological alternatives were developed for more sustainable products and cleaner production. In this work, the effect of three months of exposure under accelerated weathering conditions (ultraviolet light, moisture, and heat) on the properties of two textile waste nonwovens as a sustainable alternative to plastic mulching films was investigated. Results showed that thermostability and mechanical properties of the clothing textile waste felt and cotton waste nonwoven decreased after accelerated weathering. The chemical variation of cotton waste nonwoven and textile waste felt and the degradation rate of natural and synthetic fibers due to the photolysis and hydrolysis caused by accelerated weathering conditions were studied following the Fourier transform infrared spectroscopy and the fibrous composition variation of the blended textile waste felt structure during the study. [ABSTRACT FROM AUTHOR]