Polymers tend to have low surface free energy, a significant cause of adhesion properties with other substances. Plasma treatment is an optimal method to improve surface properties. This work used a recycled glass fiber‐polymer coating, and another based on Nylon 6,6. The surface modification of both layers was carried out with an atmospheric plasma treatment at different times. Chemical analysis of the plasma treated and the untreated surface were analyzed by infrared spectroscopy and X‐ray diffraction. Atomic force microscopy (AFM) investigated the morphology and topography surface. The plasma treatment results improve wettability and surface free energy. The contact angle decreases for Nylon 6,6 from 68° to 0° and for glass fiber‐polymer from 56° to 18°. However, the wettability remains over time in Nylon 6,6 layer, and the composite material reverts in 15 days. The high surface free energy after plasma treatment was mainly due to an increase in the polar component by inserting polar groups. The % crystallinity increases with plasma treatment due to the loss of the amorphous part of the polymer by plasma etching. AFM analysis shows an improvement in the roughness surface after treatment. These results greatly interest in enhancing adhesion with other substrates.

Polymers currently represent materials that are cost-effective, while its recycled nature is significant in terms of environmental protection. However, the surface properties of polymers often do not meet the demands of wettability, adhesion, and friction, among others. Atmospheric plasma treatment on the surface of polymers improves its physical-chemistry properties. In this work, a recycled nylon coating was prepared by the spin coating technique and characterized by Fourier transform infrared spectroscopy and X-ray diffraction. This coating was treated by atmospheric plasma, and Raman spectroscopy was performed to analyze the signals related to different functional groups present in the coating surface after plasma treatment. The action of plasma on the surface morphology was observed by scanning electron microscopy. The contact angle results showed an improvement in surface wettability.

The use of natural materials as adsorbents and the environmentally friendly removal of pollutants and azo dyes from water are important topics today. The goal of this research work was to assess the utility of Luffa cylindrica (L. cylindrica) as a natural and non-conventional adsorbent for azo dyes in water on a large scale (2 L). An azo dye (AD) at a concentration of 0.250 g/L was removed from the solution at a rate of 63.07% using 10.0 g/L doses of L. cylindrica, and the maximum adsorption capacity of L. cylindrica was 25.25 mg/g. L. cylindrica desorbed 95.8% of the AD in 0.1 M NaOH. Thermodynamically, the adsorption occurs through pseudo-second-order kinetics and the behaviors adjust better to the Langmuir isotherm. The analysis of variance (p-value < 0.05) shows that the contact time and the concentration of AD significantly influence the adsorption capacity and removal of AD. Few studies have examined the environmentally friendly removal of azo dyes from water using a natural non-conventional adsorbent.

Sustainability has converted the topic of the humanity and life-cycle analysis (LCA) is one of the main methods for evaluating the impact of each product, process, and system. Polymers, especially nylon 6,6, have found substantial relevance in several areas such as automobiles, packaging, food, batteries, etc., in the last years and estimation of their impact on the environment as well as persons from their increased disposal is of intense importance. LCA procedures are being employed to investigate the same in terms of several ecosystems, resources, and human-based restrictions but there are still some limitations to the same. This paper presents an overview of using recycled nylon 6,6 coating as an alternative to the traditional way of final disposal of this polymer, focusing on its life cycle, production, coating characterization, data reproducibility, and limitations. OpenLCA software was used for the LCA of the recycled coating formation processes. EIA09 software was employed to estimate the environmental impact assessment. Results obtained using EIA09 software show that the recycled nylon 6,6 coating has a low environmental impact with respect to soil contamination. This result shows a clear advantage of plastic recycling compared to the traditional final disposal.

This paper evaluates the stress corrosion cracking (SCC) effect in gasohol E-10 and E-85 of X-70 experimental Ni-microalloyed steel, with different aging treatments (4–12 h at 600°C). The tension tests show that for all treatment periods, the samples tensile strength and elongation increase, with the largest increment exhibited by the samples undergoing 4 and 6 h of aging treatment. Microstructural analysis showed that the microstructure remains unchanged, the increase in tensile strength in the steel is directly related to the precipitation kinetics. The slow strain rate test (SSRT) shows that the steel under all conditions presents no susceptibility to SCC, thus reducing the area ranging from 83% to 90%, with predominantly ductile fractures. The results of the polarisation tests showed no signs of pitting corrosion, as well as a low corrosion rate for both media under study.

In this work, Al–20Cu intermetallic alloy was subjected to corrosion evaluation in synthetic sea water at different pH values, and room temperature. The corrosion tests were made to study the alloy in potential applications in hydrogen generation. For this purpose, the electrochemical techniques of potentiodynamic polarisation, linear polarisation resistance, and electrochemical impedance spectroscopy were used. Experimental results showed that the alloy is not susceptible to passivation and exhibits the highest current density and corrosion rate at pH 14. In this condition, the governing corrosion mechanism was associated with activation, promoted by the continuous anodic dissolution of uncovered metallic zones, due to the detachment of previously formed corrosion products. However, the results at near-neutral pH presented higher corrosion resistance and a corrosion mechanism limited by main diffusion of ionic species. In general, the primary mechanism of corrosion in the solutions was associated to charge transfer.