Resumo em Inglês:

Abstract This paper investigates the properties of the polyaniline (PANI) on açaí vegetable fiber (AVF), hereafter referred to as PANI-COATED:AVF. Scanning electron and atomic force microscopy showed that the incorporation of PANI produced a linear surface, while optical microscopy images showed that the semiconductor layer was flawed. The complex impedance measurements performed at room temperature indicated that the electrical properties of PANI were fully transferred to the PANI-COATED:AVF and that the Cole-Cole approach dominated over a frequency range from 1 Hz to 100 kHz. Thermogravimetric analysis revealed a thermal stability range of 0° to 300°C. Finally, the combination of PANI with AVF was a successful due to the ease of processing and obtaining semiconductor filaments with wide ranges of thermal and electrical stability. This article is a complement to another recently published [doi.org/10.1002/pc.27068].

Resumo em Inglês:

Abstract A good strategy to prevent early deposition of bacteria that can form biofilms is the application of antimicrobial coatings to existing surfaces, however this field has been little explored and coatings are often non uniform in thickness. A homogeneous film of R-Carvone-Octadiene (ppCop) was deposited on different substrates (coverslip, minced coverslip and fabric) by cold plasma copolymerization to study the influence of the substrate on antimicrobial activity and show clues about the influence of octadiene on copolymerization. The ppCop showed better antimicrobial activity results on the substrate with higher effective contact area, highlighting the influence of this variable on antimicrobial activity. The ppCop deposited on minced coverslip showed an inhibition of E. coli and S. aureus bacteria by 48.69 ±0.08% and 49.31 ±0.58% respectively, with an average roughness of 14.1±0.02 nm and a static water contact angle of 79± 0.4°. The ppCop showed no cytotoxicity to the human cell line.

Resumo em Inglês:

Abstract Polyurethanes, versatile polymers extensively explored across industries, can be augmented by incorporating complementary materials like lanthanides. This research presents a novel approach, employing a one-shot synthesis to create polyurethane-lanthanide composites using polyol, isocyanate, samarium, and holmium oxides. FTIR and Raman spectroscopy affirmed successful polyurethane matrix formation, while XRD unveiled distinct phases in lanthanide-loaded matrices versus soft, low-crystallinity polyurethane in control foam. Optical microscopy displayed morphology alterations due to samarium and holmium. Thermogravimetric analysis revealed heightened composite thermal stability compared to control foam. Looking ahead, these outcomes prompt further exploration of polyurethane-lanthanide composites, particularly in harnessing property changes for diverse applications.

Resumo em Inglês:

Abstract Oil spills into water have been an environmental concern since the beginning of large-scale oil extraction. In this study, flexible open-cell polyurethane (PU) foams with added microcrystalline cellulose (MCC) were formulated and chemically modified with organosilane for use as an absorbent system for oil spill cleanup in water. The influence of cellulose concentration on mechanical properties and chemical treatment with organosilane was evaluated. The primary findings indicate that the surface treatment of the solid fraction of the foams was effective, as indicated by the contact angle, increasing the hydrophobicity of the samples. Because of the increased roughness of the PU solid fraction and the cellulose reactivity, the mechanical compressive strength and thickness of the organosilane layer increased with increasing MCC content. However, the higher the MCC content in the composition, the higher was the density, which reduced the sorption capacity of the samples.

Resumo em Inglês:

Abstract The objective of this work was to produce Pebax®/polydopamine (PDA) blends and apply these blends to produce membranes for gas separation. Flat sheet membranes were tested for gas permeation, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), wide angle x-ray diffraction (WAXD), scanning electron microscopy (SEM) and fourier transformed infrared spectroscopy (FTIR). The results show an optimal concentration of dopamine hydrochloride that produces the best results (𝛼=100, P=114 Barrer). DSC and WAXD results indicate that polydopamine influences the crystallization of Pebax®, reducing the melting and crystallization temperatures of PA blocks and increasing the melting temperature of PEO blocks. The incorporation of PDA decreases gas permeability and increases gas selectivity. The decrease in permeability indicates that the presence of polydopamine reduces the diffusion coefficient of Pebax® by reducing the segmental mobility of PEO blocks and possibly the fraction free volume. Compared to the trade-off, Pebax®/PDA membranes surpasses the upperbound for CO2/N2 separation.

Resumo em Inglês:

Abstract Bacterial cellulose (BC) is promising as a wound dressing because it is non- toxic and maintains moisture in the wound. Although BC does not have antimicrobial activity, its structure allows the incorporation of antimicrobial compounds such as essential oils (EOs). This study aims to associate BC with rosemary, clove, eucalyptus, ginger, lavender and lemongrass EOs to obtain wound dressings. The Gas Chromatography-Mass Spectrometry and Fourier Transform Infrared Spectroscopy analyses showed characteristic compounds of EOs in the incorporated membranes. These compounds reduced the thermal stability of most samples due to their different degrees of volatility. The Scanning Electron Microscopy indicated that the EOs filled the membrane pores and coated the cellulose fibers. Samples incorporated with clove, ginger and lemongrass EOs inhibited Escherichia coli, Staphylococcus aureus and Candida albicans due to the presence of eugenol and citral. The results confirmed the incorporation method's effectiveness, maintaining the composition and antimicrobial characteristics of the EOs.

Resumo em Inglês:

Abstract Most of the discarded plastics originate mainly from food and beverage packaging, thus the consumer's perception of biodegradable packaging must be understood. This study aimed to investigate the consumer perception of biodegradable packaging films made of pectin and whey protein isolate. An online questionnaire was conducted to assess the consumer responses. Results showed that the majority of consumers (77.3%) did not observe the biodegradability of the packaging during purchase, although biodegradable packaging can positively affect the purchase decision (71.9%). The acceptance, purchase intention, and preference are influenced by visual aspects, and the consumers preferred lighter and more transparent films, with less saturated colors. Consumers established correlations between color and transparency with film thickness and resistance, these correlations were not observed in the physical analysis of the film. In addition, a variety of applications were highlighted for the films produced, demonstrating the effectiveness of these materials for food and beverage packaging.