“…The results obtained for the different layers were very similar, with no thermal event between room temperature up to 400°C and a thermal event peak around 450°C. This peak is related to the thermal degradation of polymers, since thermal degradation peak of polypropylene is 480°C 25 , of cellulose is around 370°C 26 and of polyester is around 430°C 27 . Figure 3 Thermogravimetric analysis (TGA and DTG) of the four layers of untreated respirators and respirators treated by 6 cycles of H 2 O 2 plasma.…”
COVID-19 is caused by the SARS-CoV-2 virus, an emerging respiratory pathogen. The work environment represents a high risk factor for health professionals. Given the scarcity of protective personal equipment (PPE) due to global demand, decontamination and reuse studies should be carried out. Thus, the aim of this study was to evaluate the safety of a method of decontamination of N95/PFF2 respirators, especially regarding structural integrity. For that, N95/PFF2 respirators were subjected to hydrogen peroxide decontamination and analyzed using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Seven respirators of the same brand and lot were used, one being a control and the other six subjected to decontamination process. As for the sealing, a qualitative test was applied, in order to identify the changes in the structure that could damage the sealing of respirators. Results indicated that the fiber morphology in all layers was not affected by the six decontamination cycles. Also, the thermal stability in the different layers was very similar. Fit testing showed that the respiradors submitted to all cycles of decontamination were approved. Thus, it is possible to conclude that the hydrogen peroxide decontamination method is effective, since it does not alter the physical properties of the respirators.
“…The results obtained for the different layers were very similar, with no thermal event between room temperature up to 400°C and a thermal event peak around 450°C. This peak is related to the thermal degradation of polymers, since thermal degradation peak of polypropylene is 480°C 25 , of cellulose is around 370°C 26 and of polyester is around 430°C 27 . Figure 3 Thermogravimetric analysis (TGA and DTG) of the four layers of untreated respirators and respirators treated by 6 cycles of H 2 O 2 plasma.…”
COVID-19 is caused by the SARS-CoV-2 virus, an emerging respiratory pathogen. The work environment represents a high risk factor for health professionals. Given the scarcity of protective personal equipment (PPE) due to global demand, decontamination and reuse studies should be carried out. Thus, the aim of this study was to evaluate the safety of a method of decontamination of N95/PFF2 respirators, especially regarding structural integrity. For that, N95/PFF2 respirators were subjected to hydrogen peroxide decontamination and analyzed using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Seven respirators of the same brand and lot were used, one being a control and the other six subjected to decontamination process. As for the sealing, a qualitative test was applied, in order to identify the changes in the structure that could damage the sealing of respirators. Results indicated that the fiber morphology in all layers was not affected by the six decontamination cycles. Also, the thermal stability in the different layers was very similar. Fit testing showed that the respiradors submitted to all cycles of decontamination were approved. Thus, it is possible to conclude that the hydrogen peroxide decontamination method is effective, since it does not alter the physical properties of the respirators.
“…Физико-химические параметры литья под давлением аналогичны показателям, характерным для экструзии, однако имеются и некоторые принципиальные отличия. Так, процесс формования происходит в короткое время, поэтому расплав впрыскивается в форму (течет) с очень большой скоростью, что, естественно, приводит к дополнительному его разогреву [8,9]. В связи с этим в процессе вторичной переработки (рециклинга) полимеров оценка перерабатываемости материалов позволяет оценить возможное число циклов их переработки [10].…”
“…PP is a thermoplastic used in different areas, such as household products, automotive components, packaging, fabric, electrical, and electronics industries. It is the most widely used polyolefin, due to its easy processability, excellent mechanical properties, chemical resistance, and easy recycling 7–9 . It is also one of the thermoplastics most used as a polymeric matrix to obtain composite materials reinforced with lignocellulosic fibers 7,9–15 …”
Section: Introductionmentioning
confidence: 99%
“…It is the most widely used polyolefin, due to its easy processability, excellent mechanical properties, chemical resistance, and easy recycling 7–9 . It is also one of the thermoplastics most used as a polymeric matrix to obtain composite materials reinforced with lignocellulosic fibers 7,9–15 …”
This study presents the preparation of post‐consumer polypropylene (r‐PP) composites filled with 30 wt% yerba mate (YM) stick particles. To improve the fiber–matrix adhesion, three surface treatments were performed: alkaline treatment with sodium hydroxide (NaOH) and use of 3‐aminopropyltriethoxysilane (APTS) and maleic anhydride graft polypropylene copolymer (PP‐g‐MA) as coupling agents. Mechanical properties including tensile, flexural, and impact resistance were determined, and chemical (Fourier transform infrared spectroscopy [FTIR]), physical (water absorption), and morphological analyses were performed. The main findings show that the treatments were efficient in improving the mechanical properties of the composites, with emphasis on the r‐PP/YM30/APTS and r‐PP/YM30/PP‐g‐MA composites, which proved to be superior in tensile, flexion and impact strength and absorption of water compared to the untreated composite. The morphological analysis showed a better interaction between the fiber and the polymeric matrix for the composites with YM/APTS and YM/PP‐g‐MA, which corroborates the results of tensile and flexural strength, as well as with the spectra of FTIR in which the chemical modification of the fibers is observed. However, the results show that these treatments are promising in obtaining composites with recycled matrix with better properties.
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