Pyrolysis kinetic behavior of composite polypropylene-biomass solid fuels derived via co-hydrothermal carbonization process

A treatment method producing solid fuel from surgical face masks was developed to address the high cost of medical waste management and the environmental concerns of large-scale, hazardous waste dumping during the coronavirus 19 (COVID-19) pandemic. The fuel properties were investigated of solid fuel produced from surgical face masks (polypropylene material (PP)) and from PP mixed with biomass (composite PP-biomass) using a hydrothermal carbonization process (HTC), followed by pyrolysis using thermogravimetric analysis (TGA). The Coats-Redfern (CR) method was used to analyze the pyrolysis kinetics and thermodynamic parameters. The results demonstrated that the thermal decomposition of raw PP material was less stable than for its hydrochar and the fuel properties of hydrochar obtained from the PP material were substantially improved using an increased HTC temperature. The activation energy value of the raw composite PP-biomass material was higher than for its hydrochar. This research identified an option for a potentially environmental-friendly treatment method for PP-material and its utilization as solid fuel.

Properties of Composites Based on Recycled Polypropylene and Silico-Aluminous Industrial Waste.

There is an ever-growing interest in recovering and recycling waste materials due to their hazardous nature to the environment and human health. Recently, especially since the beginning of the COVID-19 pandemic, disposable medical face masks have been a major source of pollution, hence the rise in studies being conducted on how to recover and recycle this waste. At the same time, fly ash, an aluminosilicate waste, is being repurposed in various studies. The general approach to recycling these materials is to process and transform them into novel composites with potential applications in various industries. This work aims to investigate the properties of composites based on silico-aluminous industrial waste (ashes) and recycled polypropylene from disposable medical face masks and to create usefulness for these materials. Polypropylene/ash composites were prepared through melt processing methods, and samples were analyzed to get a general overview of the properties of these composites. Results showed that the polypropylene recycled from face masks used together with silico-aluminous ash can be processed through industrial melt processing methods and that the addition of only 5 wt% ash with a particle size of less than 90 µm, increases the thermal stability and the stiffness of the polypropylene matrix while maintaining its mechanical strength. Further investigations are needed to find specific applications in some industrial fields.

Material flow analysis-based assessment of polypropylene-fiber-containing microplastics released from disposable masks: Characterizing distribution in the environmental media.

With the upsurge in the use of disposable masks during the coronavirus disease pandemic, improper disposal of discarded masks and their negative impact on the environment have emerged as major issues. Improperly disposed of masks release various pollutants, particularly microplastic (MP) fibers, which can harm both terrestrial and aquatic ecosystems by interfering with the nutrient cycling, plant growth, and the health and reproductive success of organisms. This study assesses the environmental distribution of polypropylene (PP)-containing MPs, generated from disposable masks, using material flow analysis (MFA). The system flowchart is designed based on the processing efficiency of various compartments in the MFA model. The highest amount of MPs (99.7 %) is found in the landfill and soil compartments. A scenario analysis reveals that waste incineration significantly reduces the amount of MP transferred to landfills. Therefore, considering cogeneration and gradually increasing the incineration treatment rate are crucial to manage the processing load of waste incineration plants and minimize the negative impact of MPs on the environment. The findings provide insights into the potential environmental exposure associated with the improper disposal of waste masks and indicate strategies for sustainable mask disposal and management.

Face mask structure, degradation, and interaction with marine biota: A review

The COVID-19 pandemic signified an unprecedented driver of plastic pollution, mainly composed of single-use face masks (FMs). Aiming to understand their negative impact (whether aged or not)on the trophic chain, biotic (e.g., bio-incrustation) and abiotic factors (e.g., UV-light, mechanical abrasion) which affect the toxicological profile of FMs or their sub-products (mainly microplastics, MPs, and nanoplastics, PNPs) were studied. In addition to the capacity of FMs to be an immediate source of MPs/PNPs, according to reports in the scientific literature, they are also good substrates since they tend to facilitate the proliferation and transport of eukaryotic and prokaryotic organisms, pathogens such as the SARS-CoV-2 virus, contaminating water sources and facilitating the enrichment and spread of antibiotic resistance genes (ARG) in the environment. However, there is limited research on macrofouling and species dispersal. Therefore, the present review aimed to provide an updated and summarized analysis of the environmental and ecotoxicological contribution of this type of waste as well as literature regarding face mask degradation and MPs and/or PNPs release, interaction with biota, colonization in addition to recommendations for future studies.

Use of polypropylene fibers extracted from recycled surgical face masks in cement mortar.

The use of personal protective equipment (PPE), particularly single-use surgical face masks (FMs), has increased drastically owing to the ongoing Covid-19 pandemic. This study aimed to demonstrate the feasibility of utilizing recycled FM fibers in cement mortar. For this, FMs were used by removing the inner nose wires and ear loops and cutting them into two different sizes: 10 mm × 5 mm and 20 mm × 5 mm. The FMs were then introduced into five mixtures at 0 (control), 0.10, 0.15, 0.20, and 0.25 % by volume. The following mechanical properties of the mixtures were then tested: workability, density, porosity, water absorption, and the related strengths (compressive, direct tensile, and flexural). In addition, the microstructures of the mixtures were analyzed using a scanning electron microscope. The results revealed that introducing FM fibers, particularly an FM with a 5 mm diameter and 10 mm length, in the mortar increased both the tensile and flexural strengths. Among the various combinations of FMs studied, a mixture containing 0.15 % FMs exhibited the best performance. The findings of this research reveal that FMs can be reused as fibers to enhance the tensile and flexural strengths of cement mortar.

Reutilizing Single-Use Surgical Face Masks to Improve the Mechanical Properties of Concrete: A Feasibility Study

The coronavirus outbreak (COVID-19) has caused a sharp increase in the use of Single-Use Surgical Face Masks (SUSFMs) as personal protective equipment. These eventually end up in waste disposal facilities causing environmental pollution. Those that end up in the water bodies fragment into microplastics that affect marine life. Since the SUSFM materials are made from polypropylene, a thermoplastic polymer material that takes a long time to degrade, it is important to develop sustainable mitigation measures to remove them from the environment. This study investigated the feasibility of reutilizing SUSFMs in concrete. SUSFMs were shredded and added to C30/37 grade concrete in various percentages, 0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, and 3.0%, by mass of cement content. The specimens were cured for 28 days before being tested for compressive strength, splitting tensile strength, and ultrasonic pulse velocity. The compressive strength decreased with an increase in the length and dosage content. The least decrease of 10.4% was observed at 0.5% content of 30mm length of SUSFM material. The results showed that concrete improved regarding splitting tensile strength, with the highest increase of 15.2% at 0.5% content of 30mm SUSFM. In addition, the overall quality of concrete remains at UPV values of more than 4000m/s registering good quality concrete. The results underscore the use SUSFM material in concrete in order to improve its quality while at the same time reducing waste.

Silver nanoparticle-modified melt-blown polypropylene: Antibacterial and antifungal properties and antiviral activity against SARS-CoV-2.

Melt-blown polymer fiber materials are frequently used in the face mask manufacturing. In the present work, a melt-blown polypropylene tape was modified by silver nanoparticles using chemical metallization. The silver coatings on the fiber surface consisted of crystallites 4-14 nm in size. For the first time, these materials were comprehensively tested for antibacterial, antifungal and antiviral activity. The silver-modified materials showed antibacterial and antifungal activities, especially at high concentrations of silver, and were found to be efficient against the SARS-CoV-2 virus. The silver-modified fiber tape can be used in the face mask manufacturing and as an antimicrobial and antiviral component in filters of liquid and gaseous media.

ZnO coated nonwoven polypropylene fabric with antibacterial and antiviral function for medical applications

The present pandemic has highlighted the necessity of infection protection gear as a crucial protective approach, particularly given the fact that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) readily infects individuals in poorly ventilated environments. Embedding antimicrobial function onto protection gear would have major implications in minimizing pathogen contamination and lowering healthcare associated illness. In this study, non woven polypropylene fabric (NWPP) which is widely used in personal hygiene products and hospital protective gears has been subjected to surface fictionalization with corona treatment. Surface polarity of the treated fabric was studied by use of dyne liquid which showed generation of surface polarization. Subsequently, the resultant surface polarized NWPP were spray coated with zinc oxide (ZnO) antiviral agent. The antiviral agents were rendered to adhere to NWPP by use of polyurethane solution coating on the fabric. The effect of antiviral coatings on NWPP fabric with the use of polyurethane solution as an adhesive were investigated in terms of antiviral activity and anti-bacterial activity against MS2 bacteriophage and Staphylococcus aureus and Klebsiella pneumonia bacteria respectively. Coating of surface polarized NWPP with polyurethene binder reduced the leaching of antiviral coating. More importantly, the fabrics exhibited promising antiviral and anti bacterial activity with 99.90 % reduction in microorganisms after 24 hours of exposure. © 2022 IEEE.

A novel investigations on medical and non-medical mask performance with influence of marine waste microplastics (polypropylene).

The entire human race is struggling with the spread of COVID-19. Worldwide, the wearing of face masks is indispensable to prevent such spread. Despite numerous studies reporting on the fabrication of face masks and surgical masks to reduce spread and thus human deaths, this novel work is considered the marine waste of microplastics, namely Polypropylene (PP) polymer, used to fabricate non-woven fabric masks through the melt-blown process. This experimental work aims to maximize the mask's quality and minimize its fabrication cost by optimizing the melt-blown process parameters and using microplastics. The melt-blown process was used to make masks. Parameters such as extruder temperature, hot air temperature, melt flow rate, and die-to-collector distance (DCD) were investigated as independent variables. The quality of the mask was investigated in terms of bacterial filtration efficiency (BFE), particle filtration efficiency (PFE), and differential pressure. The Taguchi L16 orthogonal array and Taguchi analysis were employed for experimental design and statistical optimization, respectively. The results reveal that the higher BFE and PFE are recorded at 96.7 % and 98.6 %, respectively. The surface morphological investigation on different layers ensured the fine and uniform porosity of the layers and exhibited minimum breath resistance (a low differential pressure of 0.00152 kPa/cm2). Hence the chemically treated marine waste microplastics improved the masks' performance.

Aerosol charge neutralization and its impact on particle filtration efficiency of common face mask materials

Despite the significant increase in research on mask filtration testing since the COVID-19 pandemic, there remains considerable ambiguity regarding which parameters affect particle filtration efficiency (PFE) and how differences in standard testing protocols can lead to divergent PFE values. We evaluated the PFE (and differential pressure) of several common face masks and community face mask materials including woven cotton, spunbond polypropylene, and meltblown polypropylene, testing in accordance with ASTM F2100/2299 standards for medical masks, using polystyrene latex (PSL) aerosol, as well as NIOSH standards for respirators, using NaCl aerosol. In both cases, PFE was measured with and without aerosol charge neutralization, which is used to bring the particle population to a known, equilibrium bipolar charge distribution. Aerosols of either composition that were not neutralized (untreated) led to significant increases in measured PFE, especially in the case of PSL. In contrast, effective neutralization led to lower PFE measurements that also showed little to no dependence on aerosol composition across most materials. To investigate further, the bipolar charge distributions of PSL and NaCl aerosols, both neutralized and untreated, were characterized using an aerodynamic aerosol classifier operated in tandem with a scanning mobility particle sizer (AAC-SMPS). This technique illustrated the differences in the distribution of particle charge states between PSL and NaCl aerosols of the same size, and between PSL particles of different sizes, revealing the presence of highly charged particles in many cases. Most importantly, the equilibrium charge distribution after neutralization is shown to be independent of particle composition or initial charge distribution, highlighting the crucial role of aerosol charge neutralizers in preventing overestimates of mask performance (due to electrostatic effects) and promoting consistency in standard testing procedures.

Using Fibre recovered from face mask waste to improve printability in 3D concrete printing

Surgical face mask usage has rapidly increased in the last two years due to the COVID-19 pandemic. This generates vast amounts of plastic waste, causing significant risks to the ecosystem. Thus, this study assesses the potential of using recycled fibre from face mask waste as fibre reinforcement in 3D concrete printing (3DCP) applications to improve printability while reducing landfill waste. The effect of recycled fibre from waste face masks on the rheological characteristics of printable mixes and the mechanical performance of printed elements was evaluated for different contents of shredded face masks (i.e., 1% and 2% by vol). The rheological properties like static and dynamic yield strengths, apparent viscosity, and thixotropic behaviour, along with compressive and flexural strength, were evaluated for 3D printed specimens and mechanical properties were compared to their mould-cast counterparts. Further, the variation in the interlayer bond strength and porosity due to different fibre dosages was also investigated. In addition, a comparative study on the fresh and hardened properties was performed for the printable mixes with polypropylene (PP) fibres and face masks. The addition of face masks significantly improved the rheological properties with good extrudability and buildability for all the dosages. Compared to face masks, mixes with PP fibres showed poor extrudability with higher fibre dosages. The compressive strength was increased by 41% for a 1% dosage of face masks when compared to the unreinforced concrete. Furthermore, the flexural strength when tested along the weaker interface, showed an increase of 74% and 82% for the addition of 1% and 2% face mask content. The interlayer bond strength of 1% face mask content showed 21% improvement and was observed to have the highest surface moisture content. The mechanical performance of face masks and PP fibres are observed to be comparable for 1% dosage. The mechanical properties of printed and mould-cast specimens were also observed to be similar. [ FROM AUTHOR] Copyright of Cement & Concrete Composites is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

ANALYSIS OF THE EFFECT OF USING COVID-19 MEDICAL MASK WASTE WITH POLYPROPYLENE ON THE COMPRESSIVE STRENGTH AND SPLIT TENSILE STRENGTH OF HIGH-PERFORMANCE CONCRETE

The coronavirus causing the Covid-19 pandemic has been experienced by us since 2020, which has led to an increase in the use of disposable medical masks in Indonesia and even worldwide. Polypropylene is a thermoplastic polymer used as the main ingredient in medical masks that takes more than 25 years to decompose in landfills. This research offers an innovative way to use medical mask waste in high-performance concrete. The resulting medical mask waste is subjected to a sterilization process and cut into fibers to analyze the effect of its addition on the compressive strength and splitting tensile strength of high-performance concrete. The research began with testing the physical and mechanical properties of the materials, designing a concrete mix using the absolute volume method, and taking samples for compression and splitting tests. The variation in the ratio of water-cement and pozzolanic materials w (c+p) is 0.32. As a result, the compressive strength of concrete increased with a fiber size of 5×0.5 cm and 2×0.5 cm. An increase is up to 7 % with an optimum value of 72.37 MPa with a fiber size of 2×0.5 cm and a content of 0.15 %. However, there was a decrease in the compressive strength with a 5×1 cm mask fiber size. The overall split tensile strength value of all variations in waste fiber size and content increased with an optimum value of 7.29 MPa at 0.20 % fiber content with a fiber size of 5×0.5 cm. This indicates that polypropylene fibers from medical mask waste have a positive effect on high-performance concrete, namely improve the properties of concrete with a low tensile strength, which is expected to inhibit the propagation and reduce the size of cracks in reinforced concrete structures © 2023

A first report on the spatial and temporal variability of microplastics in coastal soils of an urban town in south-western India: Pre- and post-COVID scenario.

We present a first study on the temporal changes (2019-2021) in the microplastic abundance in the coastal soils of an urban town in the south-western part of India. All sampling stations exhibited higher abundances of microplastics in soils collected during 2021 (959.7 ± 277.7 particles/kg) compared to those collected in 2019 (515.1 ± 182.7 particles/kg). Morphologically, flakes, fibres, and films are the most abundant types documented in the soil environment. The microplastics of 0.3-5 mm size are relatively more abundant (60.6 %) compared to those of 0.03-0.3 mm size (39.4 %) in 2021. The three main types of polymers (polypropylene and high- and low-density polyethylene) in the soil exhibited an increase in abundance during an interval of 15 months (October 2019 to March 2021). In addition to packaging materials, the enhanced use of surgical masks during the COVID-19 period might have acted as a source of microplastic contamination in the soils.

Development of a desktop mask charger.

Polypropylene mesh, integrated in N95 respirators and surgical masks that are widely used in the current crisis of COVID-19, filters aerosols via electrostatics in addition to the physical block. However, any contact to water such as storage under high humidity, exposure to exhaling breath, and washing in water removes its charges and thus compromises its filtering efficiency. We developed a desk top device based on a Cockcroft-Walton's voltage multiplier that can restore the electrostatic charge of surgical masks within 1 min and recover the filtering efficiency of the polypropylene mesh from 87% to 97%. The device is easy to operate and safe, thus may be applied for the reuse of surgical masks towards reducing the plastic wastes.

Satisfaction of patients after implant-based subpectoral reconstruction with a titanized polypropylene mesh (TiLOOP Bra) compared to prepectoral reconstruction with a titanzied polypropylene pocket (TiLOOP Bra Pocket)

Introduction Patients' satisfaction after breast reconstruction can be evaluated with validated questionnaires as the Breast-Q questionnaire. The Breast-Q questionnaire includes different domains;one of them is "satisfaction with the result". Material(s) and Method(s): In the multicentre, prospective studies PRO (patient related outcome)-BRA (clinicaltrials.gov: NCT01885572) and PRO-Pocket (clinicaltrials.gov: NCT03868514), patient satisfaction was assessed using the Breast-Q questionnaire. In the PRO-Bra study, 269 patients underwent subpectoral surgery using the TiLOOP Bra polypropylene mesh (pfm medical ag, Germany). In the 'PRO-Pocket' study, 311 patients underwent prepectoral surgery using the TiLOOP Bra Pocket polypropylene mesh. For the evaluation, those patients from the PRO-Bra and PRO-Pocket studies who completed a Breast-Q questionnaire 6 and/or 12 months after surgery were included. The BreastQ score is measured from 0 to 100, with a score of 100 corresponding to 'very satisfied'. Satisfaction with the result of the breast reconstruction was evaluated. Result(s): In the PRO-Bra study, a total of 221 and 203 patients completed a Breast-Q at 6 months and/or 12 months FU, respectively. The mean age and BMI of the patients with completed Breast-Q were comparable between the two studies (PRO-Bra: 49.3 [+/-11.6] years, 22.9 kg/m2 [+/-3.5];PRO-Pocket: 47.7 [+/-11.7] years, 24.5 kg/m2 [+/-4.3]). In the PRO-Pocket study, a total of 258 and 266 patients completed a Breast-Q at 6 months and/or 12 months FU, respectively. In the PRO-Bra study the mean score of satisfaction with the result at 6 months follow-up (FU) was 74.5 (+/-19.9), in the PRO-Pocket 79.1 (+/-19.1), at 12 months FU the mean scores were 76.3 (+/-18.9) for PRO-Bra and 78.2 (+/-20.4) for PRO-Pocket. Furthermore, stratification according to age (cutoff 50 years) or BMI (cutoff 25 kg/m2) did not reveal any differences between the subgroups or the two studies (see Table). PRO-Bra PRO-Pocket mean score (+/-SD) 6 months 12 months 6 months 12 months BMI <= 25 75.1 (+/-19.7) 76.4 (+/-17.8) 77.7 (+/-19.9) 78.9 (+/-19.8) BMI > 25 72.1 (+/-20.7) 76.1 (+/-22.9) 82.1 (+/-16.9) 76.8 (+/-21.8) age <= 50 76.4 (+/-18.7) 77.0 (+/-18.9) 80.1 (+/-18.7) 78.1 (+/-19.6) age > 50 71.5 (+/-21.5) 75.3 (+/-19.0) 77.5 (+/-19.5) 78.4 (+/-21.8) Conclusion(s): Our data so far show high patient satisfaction with overall outcome of the surgery. In addition, patients' satisfaction with the result was comparable after subpectoral as well as prepectoral implant placement. This is particularly important in the PRO-Pocket study, as approximately 60% of the operations and the follow-up period took place during the COVID-19 pandemic.

The use of ilioinguinal and iliohypogastric nerve block anesthesia in inguinal bladder hernia repair Minimally invasive anesthesia technique in inguinal bladder hernia repair

Aim: There are data showing that the use of minimally invasive anesthesia methods (local anesthesia, nerve blocks) as an alternative to traditional anesthesia methods used in inguinal hernia repair surgery is safe and effective. During the COVID-19 pandemic, which affected the whole world, we aimed to evaluate the use of minimally invasive anesthesia methods in patients with inguinal bladder hernia, as well as their perioperative and postoperative results in our pilot study. Material(s) and Method(s): We evaluated the perioperative and postoperative data of five patients with inguinal bladder hernia, who underwent surgery with local anesthesia and ilioinguinal/iliohypogastric nerve blockade, four of which were performed during the COVID-19 pandemic. Result(s): It is possible to perform inguinal bladder hernia surgery with local anesthesia and ilioinguinal/iliohypogastric nerve block, including in secondary cases. Better hemodynamic stabilization in the intraoperative period reduces the need for narcotic analgesics by providing effective analgesia in the postoperative period, as well as reducing the risk of contamination in airway control. Discussion(s): Performing inguinal bladder hernia surgery using local anesthesia and ilioinguinal/iliohypogastric nerve block provides reliable and effective analgesia during the perioperative and postoperative periods.Copyright © 2023, Derman Medical Publishing. All rights reserved.

THE USED SURGICAL MASKS: FROM WASTE TO RESOURCE

The general focus of research is the development of recycling protocols for disposable surgical masks into new raw materials for different possible applications. Separation of various constituent materials was performed by manual procedure or by water floating. The potentially targeted end applications are thin film and glass fibre composites. Polypropylene thin-films with a thickness of 100 micron were produced by compounding the face mask polymer with different content of a virgin PP, in the range 20-80 wt%. Face mask polypropylene (FM-PP) composites containing glass fibre of 15 wt% and 30 wt% were also prepared, evidencing an improvement of stiffness and strength, furtherly increased in presence of coupling agent. © 2022 Fambri et al.

Preparation and property of electrospining nanocopper oxide antibacterial composite nonwovens

The spread and variation of COVID-19 in the world have seriously threatened human health. Therefore the current focus of research is to develop medical and antiepidemic textiles with high filtering efficiency and bacteriostasis and low filtering resistance. Polypropylene PP melt-blown nonwovens are commonly used as raw materials for medical antiepidemic textiles. PP melt-blown nonwovens as the core filter layer of medical textiles were difficult to buy during the outbreak of the epidemic. However the traditional PP melt-blown nonwovens have low antibacterial performance and medical staff are vulnerable to virus infection and microbial damage in the process of use for their single function and certain limitations in protective ability. Therefore in the post-pandemic era PP melt-blown nonwovens should not only be able to meet the rigid demand of the market but also evolve to be high-end and functional in the face of mutating COVID-19 and the possibility of a return at any time. The research combines the PP melt-blown nonwoven with the electrospinning nanofiber membrane to prepare compound nonwoven fabrics with high antibacterial activity. In order to improve the antibacterial property of PP melt-blown nonwovens composite nanofiber membranes were synthesized on PP melt-blown nonwovens by electrospinning technology. Firstly the PP melt-blown nonwoven was used as receiving substrate of electrospinning equipment and nano copper oxide CuO-NPS was used as anti-bacterial material to prepare the PP / PAN / CuO-NPS composite nonwovens with high antibacte-rial performance. On the basis of that effects of the CuO-NPS mass fraction and electrospinning time on the surface morphology fiber diameter distribution chemical constitution filtration performance hydrophobicity and antibacterial property of composite nonwovens were studied. The results show that the bacteriostasis rates of composite nonwovens to gram-negative E. coli and gram-positive S. aureus are both greater than 99. 99% in the range of CuO-NPS mass fraction of 0. 3% - 0. 9% and the spinning time is 1 h. When the spinning time is 1 h as the mass fraction of CuO-NPS increases the fiber diameter of the composite nonwoven increases and its distribution uniformity of diameter and hydrophobic property both decrease. Under the condition of constant mass fraction of CuO-NPS the filtration efficiency of composite nonwovens improves with the extension of the spinning time but the permeability decreases. With the same spinning time the filtration efficiency of composite nonwovens increases with the increase in CuO-NPS mass fraction. In addition in-corporating CuO-NPs into PAN nanofiber membrane does not change the chemical structure of the membrane. We select polyacrylonitrile PAN with good spinning performance as the raw material and CuO-NPs as the antibacterial material to prepare CuO-NPs powder with antibacterial properties to prepare electrostatic spinning solution. The composites of PP melt-blown nonwovens and electrospun PAN / CuO-NPs nanofibrous membrane have been obtained which not only improves the filtration performance of PP melt-blown nonwovens but also endows them with efficient antibacterial property. This paper provides a reference for further studies on the production and application of PP melt-blown nonwovens. (English) [ABSTRACT FROM AUTHOR] 针对聚丙烯( PP)熔喷非织造布抗菌性能不足的问题,本文以 PP 熔喷非织造布为静电纺丝装置的接受基布、 CuO-NPs 为抗菌材料,制备具有高效抗菌性能的聚丙烯 / 聚丙烯腈 / 纳米氧化铜( PP / PAN / CuO-NPs) 复合非织造布。 研究了 CuO-NPs 质量分数 与 静 电 纺 丝 时 间 对 复 合 非 织 造 布 抗 菌 等 性 能 的 影 响。 结 果 表 明:当 纺 丝 时 间 为 1 h、 CuO-NPs 质量分数在 0. 3% ~ 0. 9% 时,复合非织造布对 E. coli 和 S. aureus 的抑菌率均 > 99. 99% 。 纺丝时间为 1 h, 随着 CuO-NPs 质量分数增大,复合非织造布纤维直径增大、直径分布均匀性降低、疏水性能下降。 CuO-NPs 质量分 数不变,随着纺丝时间增加,复合非织造布的过滤效率提升,透气性却下降。 纺丝时间相同,复合非织造布的过滤效 率随着 CuO-NPs 质量分数增大而增大;CuO-NPs 质量分数增大时,复合非织造布的透气性在较短纺丝时间( 0. 5 ~ 1 h)内先下降后提升,在较长纺丝时间(1. 5 ~ 2. 5 h)内显著下降。 此外,CuO-NPs 的加入不会改变 PAN 纳米纤维膜 的化学结构。 静电纺纳米纤维膜与 PP 基布的复合可以制备高效过滤和抑菌的医用防疫纺织品。 (Chinese) [ABSTRACT FROM AUTHOR] Copyright of Journal of Silk is the property of Zhejiang Sci-Tech University Magazines and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Structure, Morphology, and Surface Chemistry of Surgical Masks and Their Evolution up to 10 Washing Cycles

The Covid-19 crisis has led to a massive surge in the use of surgical masks worldwide, causing risks of shortages and high pollution. Various decontamination techniques are currently being studied to reduce these risks by allowing the reuse of masks. In this study, surgical masks were washed up to 10 times, each cycle under the same conditions. The consequences of the washing cycles on the structure, fiber morphology, and surface chemistry have been studied through several characterization techniques: scanning electron microscopy, wetting angle measurements, infrared spectroscopy, X-ray diffraction, and X-ray photoelectrons spectroscopy. The washing process did not induce large changes in the hydrophobicity of the surface, the contact angle remaining constant throughout the cycles. The composition observed in the IR spectrum also remained unchanged for washed masks up to 10 cycles. Some slight variations were observed during X-ray analysis: the crystallinity of the fibers as well as the size of the crystals increases with the number of wash cycles. The XPS analysis shows that after 10 cycles, the surface of the masks underwent a slight oxidation. In the SEM images, changes were observed in the arrangement of the fibers, which are more visible the more times the mask has been washed: they align themselves in bundles, form areas with holes in the mask layer, and are crushed in some areas. © 2023 American Chemical Society