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Particle and Fibre Toxicology Jan 2023Polypropylene (PP) is used in various products such as disposable containers, spoons, and automobile parts. The disposable masks used for COVID-19 prevention mainly...
BACKGROUND
Polypropylene (PP) is used in various products such as disposable containers, spoons, and automobile parts. The disposable masks used for COVID-19 prevention mainly comprise PP, and the disposal of such masks is concerning because of the potential environmental pollution. Recent reports have suggested that weathered PP microparticles can be inhaled, however, the inhalation toxicology of PP microparticles is poorly understood.
RESULTS
Inflammatory cell numbers, reactive oxygen species (ROS) production, and the levels of inflammatory cytokines and chemokines in PP-instilled mice (2.5 or 5 mg/kg) increased significantly compared to with those in the control. Histopathological analysis of the lung tissue of PP-stimulated mice revealed lung injuries, including the infiltration of inflammatory cells into the perivascular/parenchymal space, alveolar epithelial hyperplasia, and foamy macrophage aggregates. The in vitro study indicated that PP stimulation causes mitochondrial dysfunction including mitochondrial depolarization and decreased adenosine triphosphate (ATP) levels. PP stimulation led to cytotoxicity, ROS production, increase of inflammatory cytokines, and cell deaths in A549 cells. The results showed that PP stimulation increased the p-p38 and p-NF-κB protein levels both in vivo and in vitro, while p-ERK and p-JNK remained unchanged. Interestingly, the cytotoxicity that was induced by PP exposure was regulated by p38 and ROS inhibition in A549 cells.
CONCLUSIONS
These results suggest that PP stimulation may contribute to inflammation pathogenesis via the p38 phosphorylation-mediated NF-κB pathway as a result of mitochondrial damage.
Topics: Animals; Mice; Cytokines; Inflammation; Microplastics; NF-kappa B; Pneumonia; Polypropylenes; Reactive Oxygen Species
PubMed: 36624477
DOI: 10.1186/s12989-022-00512-8 -
Polymers May 2023Nowadays, usable plastic materials with defined properties are created by blending additives into the base polymer. This is the main task of compounding on co-rotating...
Nowadays, usable plastic materials with defined properties are created by blending additives into the base polymer. This is the main task of compounding on co-rotating twin-screw extruders. The thermal and mechanical stress occurring in the process leads to a mostly irreversible damage to the material. Consequently, the properties of the polymer melt and the subsequent product are affected. The material degradation of polypropylene (PP) on a 28 mm twin-screw extruder has already been studied and modeled at Kunststofftechnik Paderborn. In this work, the transferability of the previous results to other machine sizes and polypropylene compounds were investigated experimentally. Therefore, pure polypropylene was processed with screw diameters of 25 mm and 45 mm. Furthermore, polypropylene compounds with titanium dioxide as well as carbon fibers were considered on a 28 mm extruder. In the course of the evaluation of the pure polypropylene, the melt flow rates of the samples were measured and the molar masses were calculated on this basis. The compounds were analyzed by gel permeation chromatography. As in the previous investigations, high rotational speeds, low throughputs and high melt temperatures lead to a higher material degradation. In addition, it is illustrated that the previously developed model for the calculation of material degradation is generally able to predict the degradation even for different machine sizes by adjusting the process coefficients. In summary, this article shows that compounders can use the recommendations for action and the calculation model for the material degradation of polypropylene, irrespective of the machine size, to design processes that are gentle on the material.
PubMed: 37177327
DOI: 10.3390/polym15092181 -
Polymers Jul 2020Polypropylene (PP) is a commodity plastic known for high rigidity and crystallinity, which is suitable for a wide range of applications. However, high flammability of PP... (Review)
Review
Polypropylene (PP) is a commodity plastic known for high rigidity and crystallinity, which is suitable for a wide range of applications. However, high flammability of PP has always been noticed by users as a constraint; therefore, a variety of additives has been examined to make PP flame-retardant. In this work, research papers on the flame retardancy of PP have been comprehensively reviewed, classified in terms of flame retardancy, and evaluated based on the universal dimensionless criterion of (). The classification of additives of well-known families, i.e., phosphorus-based, nitrogen-based, mineral, carbon-based, bio-based, and hybrid flame retardants composed of two or more additives, was reflected in mirror calculated from cone calorimetry data, whatever heat flux and sample thickness in a given series of samples. PP composites were categorized in terms of flame retardancy performance as , , or cases. It also attempted to correlate other criteria like UL-94 and limiting oxygen index (LOI) with values, giving a broad view of flame retardancy performance of PP composites. The collected data and the conclusions presented in this survey should help researchers working in the field to select the best additives among possibilities for making the PP sufficiently flame-retardant for advanced applications.
PubMed: 32751298
DOI: 10.3390/polym12081701 -
Annali Di Igiene : Medicina Preventiva... 2021Health authorities and organizations consider non-medical face masks as an additional passive means to prevent virus diffusion. Communication strategies disseminate... (Review)
Review
BACKGROUND
Health authorities and organizations consider non-medical face masks as an additional passive means to prevent virus diffusion. Communication strategies disseminate information among the population that such masks are essential for mitigating virus diffusion. However, scientific studies are not conclusive in showing the undisputed filtration efficiency of fabric/cloth facial masks (both commercial and homemade).
OBJECTIVES
This study examines scientific data about the effectiveness of face masks before and during the COVID-19 emergency. Present trends in the making of commercial and homemade fabric/cloth face masks are also examined.
METHODS
Statistical data of published studies are analyzed and compared. Main considerations and sugge-stions are also extracted and discussed. Current approaches are examined for assessing the characteristics and effectiveness of fabric/cloth commercial and homemade face masks intended for the population.
RESULTS
Conflicting data exist as to whether non-medical masks have a protective effect from the spread of respiratory viruses. Both medical masks (MDs) and respiratory personal protection equipment (PPE) show a given effectiveness value.
CONCLUSION
Concerning commercial and homemade fabric/cloth masks, giving general indications on the choice of materials and their assemblage is difficult as it is not possible to assess the effectiveness of the filter media with respect to the kind of multiphase fluid that may be emitted upon breathing, sneezing, or coughing under different environmental conditions. This is particularly important because airflow rate, temperature, humidity, and duration of use will affect the performance of filter media. Moreover, while a mask may have excellent filter media, droplets may leak into the face-piece unless there is an adequate facial seal. In the presence of leaks, any type of mask may actually offer less protection independently of its nominal filtering effìciency.
Topics: Aerosols; Air Microbiology; COVID-19; Cough; Equipment Design; Evaluation Studies as Topic; Filtration; Humans; Humidity; Masks; Polypropylenes; Respiration; SARS-CoV-2; Sneezing; Temperature; Textiles
PubMed: 33258868
DOI: 10.7416/ai.2020.2390 -
The Science of the Total Environment Apr 2023The global health crisis caused by the COVID-19 pandemic has resulted in massive plastic pollution from the use of personal protection equipment (PPE), with... (Review)
Review
The global health crisis caused by the COVID-19 pandemic has resulted in massive plastic pollution from the use of personal protection equipment (PPE), with polypropylene (PP) being a major component. Owing to the weathering of exposed PPEs, such contamination causes microplastic (MP) and nanoplastic (NP) pollution and is extremely likely to act as a vector for the transportation of COVID-19 from one area to another. Thus, a post-pandemic scenario can forecast with certainty that a significant amount of plastic garbage combined with MP/NP formation has an adverse effect on the ecosystem. Therefore, updating traditional waste management practices, such as landfilling and incineration, is essential for making plastic waste management sustainable to avert this looming catastrophe. This study investigates the post-pandemic scenario of MP/NP pollution and provides an outlook on an integrated approach to the recycling of PP-based plastic wastes. The recovery of crude oil, solid char, hydrocarbon gases, and construction materials by approximately 75, 33, 55, and 2 %, respectively, could be achieved in an environmentally friendly and cost-effective manner. Furthermore, the development of biodegradable and self-sanitizing smart PPEs has been identified as a promising alternative for drastically reducing plastic pollution.
Topics: Humans; Microplastics; Plastics; Pandemics; Ecosystem; COVID-19; Polypropylenes
PubMed: 36621482
DOI: 10.1016/j.scitotenv.2023.161390 -
BioMed Research International 2020It is currently unknown whether an association exists between polypropylene mesh and urethral diverticulum formation following placement of polypropylene midurethral... (Review)
Review
AIMS
It is currently unknown whether an association exists between polypropylene mesh and urethral diverticulum formation following placement of polypropylene midurethral slings (MUS) for the treatment of stress urinary incontinence (SUI). We aimed to examine the literature associating MUS with the occurrence of urethral diverticula.
METHODS
Multiple online research databases, including PubMed, Google Scholar, EBSCOhost, and the Cochrane Library, were searched, from January 2019 to February 2019, for evidence related to the occurrence of urethral diverticula following polypropylene MUS procedures.
RESULTS
Four case reports were published demonstrating the occurrence of urethral diverticula following the use of polypropylene mesh for surgical treatment of SUI. Subjects of these cases were menopausal and had an elevated body mass index (BMI), recurrent urinary tract infections (UTIs), autoimmune conditions, or prior pelvic floor surgeries. A thorough urologic workup, including imaging prior to sling placement, was not always performed.
CONCLUSION
No clear association exists between polypropylene MUS placement and subsequent urethral diverticulum formation. Factors that diminish polypropylene mesh biocompatibility include elevated BMI, menopause, recurrent UTIs, prior pelvic surgeries, and preexisting medical conditions. Symptoms associated with urethral diverticula should prompt a complete urologic workup prior to MUS placement.
Topics: Adult; Diverticulum; Humans; Middle Aged; Polypropylenes; Suburethral Slings; Surgical Mesh; Urethral Diseases; Urinary Incontinence, Stress
PubMed: 32462011
DOI: 10.1155/2020/6761581 -
Heliyon Apr 2023Polypropylene mesh, integrated in N95 respirators and surgical masks that are widely used in the current crisis of COVID-19, filters aerosols via electrostatics in...
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.
PubMed: 37089360
DOI: 10.1016/j.heliyon.2023.e15359 -
The Indian Journal of Tuberculosis Jan 2021To introduce a new method to do safe bronchoscopy, a highly aerosol generating procedure through disposable COVID box in this difficult COVID time.
OBJECTIVE
To introduce a new method to do safe bronchoscopy, a highly aerosol generating procedure through disposable COVID box in this difficult COVID time.
METHODS
We have introduced an unbelievably cheap and effective method "DISPOSABLE COVID BOX". We took an acrylic board 70 × 20 cm and attached 3 bars 32 cm long and slide it under the side of the patient. A similar contraption is used on the other side. Then, it is covered by a polypropylene sheet 2' × 2'. It makes a completely disposable airtight chamber with the polypropylene sheet. We make a 1 cm nick in the sheet and introduce the video-bronchoscope, which is further navigated into the patient without any discomfort either to the patient or Bronchoscopist. When the procedure is finished, scope is withdrawn from the patient and the polypropylene sheet is squeezed out. The polypropylene sheet is removed and disposed off with all precautions, and the acrylic boards and the bars are cleaned with 1% Sodium hypochlorite solution. This way, the cost is only of polypropylene sheet which is negligible.
RESULTS
Videobronchoscopies in indicated patients were done using this novel disposable covid box. This new invention called Disposable COVID box has been practiced for the first time, it's an innovative technique about which we want the world to be known.
CONCLUSION
To conclude, there are no aerosols released in atmosphere after the procedure, making it absolutely safe for bronchoscopist and at same time patient also remains safe. We are ready again in no time with fresh polypropylene sheet to do the next bronchoscopy.
Topics: Bronchoscopy; COVID-19; Humans; Infectious Disease Transmission, Patient-to-Professional; Personal Protective Equipment; SARS-CoV-2
PubMed: 33641838
DOI: 10.1016/j.ijtb.2020.09.024 -
Molecules (Basel, Switzerland) Jun 2021Pluronic polymers (pluronics) are a unique class of synthetic triblock copolymers containing hydrophobic polypropylene oxide (PPO) and hydrophilic polyethylene oxide... (Review)
Review
Pluronic polymers (pluronics) are a unique class of synthetic triblock copolymers containing hydrophobic polypropylene oxide (PPO) and hydrophilic polyethylene oxide (PEO) arranged in the PEO-PPO-PEO manner. Due to their excellent biocompatibility and amphiphilic properties, pluronics are an ideal and promising biological material, which is widely used in drug delivery, disease diagnosis, and treatment, among other applications. Through self-assembly or in combination with other materials, pluronics can form nano carriers with different morphologies, representing a kind of multifunctional pharmaceutical excipients. In recent years, the utilization of pluronic-based multi-functional drug carriers in tumor treatment has become widespread, and various responsive drug carriers are designed according to the characteristics of the tumor microenvironment, resulting in major progress in tumor therapy. This review introduces the specific role of pluronic-based polymer drug delivery systems in tumor therapy, focusing on their physical and chemical properties as well as the design aspects of pluronic polymers. Finally, using newer literature reports, this review provides insights into the future potential and challenges posed by different pluronic-based polymer drug delivery systems in tumor therapy.
Topics: Drug Carriers; Drug Delivery Systems; Humans; Hydrophobic and Hydrophilic Interactions; Neoplasms; Poloxamer; Polyethylene Glycols; Polymers; Polypropylenes; Propylene Glycols; Tumor Microenvironment
PubMed: 34204668
DOI: 10.3390/molecules26123610 -
Scientific Reports Mar 2023One of the objectives of the circular economy is solving the world's plastic pollution crisis and recycling of materials by ensuring less waste. The motivation of this...
One of the objectives of the circular economy is solving the world's plastic pollution crisis and recycling of materials by ensuring less waste. The motivation of this study was to demonstrate the possibility of recycling two types of wastes with a high risk of pollution, such as plastic based polypropylene and abrasive blasting grit wastes in asphalt roads. The effects of adding together polypropylene based microplastics and grit waste in asphalt mixture for wear layer performance have been shown in this study. The morphology and elemental composition of the hot asphalt mixture samples before and after freeze-thaw cycle were examined by SEM-EDX and the performance of the modified asphalt mixture was determined with laboratory tests including Marshall stability, flow rate, solid-liquid report, apparent density, and water absorption. A hot asphalt mixture suitable for making wear layer in road construction, containing aggregates, filler, bitumen, abrasive blasting grit waste and polypropylene based microplastics is also disclosed. In the recipe of modified hot asphalt mixtures were added 3 proportions of polypropylene-based microplastics such as 0.1%, 0.3% and 0.6%. An improvement of the mixture performance is shown at the asphalt mixture sample with 0.3% of polypropylene. In addition, polypropylene-based microplastics are bond with aggregates from mixture well, so the polypropylene-modified hot asphalt mixture can effectively decrease the appearance of cracks during sudden temperature changes.
PubMed: 36871062
DOI: 10.1038/s41598-023-30857-9