-
Molecules (Basel, Switzerland) Jul 2022Multilayered materials are widely studied due to their special structures and great properties, such as their mechanical ones. In this paper a novel and effective...
Multilayered materials are widely studied due to their special structures and great properties, such as their mechanical ones. In this paper a novel and effective technique, a quadruple-layering approach, was used to fabricate multilayered materials. This approach increases the number of layers rapidly via simple operations. Materials with 4, 16, and 64 layers with alternating layers of polypropylene and nanocomposites were fabricated using this approach, and their film morphology and mechanical properties were studied. The influence of the number of layers on the mechanical properties of the materials and the relationship between the mechanical properties of each material were investigated. The results illustrated that the tensile modulus and strength were enhanced and elongation at the break increased when the layer numbers of the multilayered materials increased. However, this approach has a defect in that as the layer number increases, the layer thickness was not uniform, thus restricting the improvement of properties. This may need to be further studied in future work.
Topics: Nanocomposites; Polypropylenes
PubMed: 35956803
DOI: 10.3390/molecules27154852 -
International Journal of Molecular... May 2023Currently, polypropylene (PP) is used in various products, thus leading to high daily exposure in humans. Thus, it is necessary to evaluate the toxicological effects,...
Currently, polypropylene (PP) is used in various products, thus leading to high daily exposure in humans. Thus, it is necessary to evaluate the toxicological effects, biodistribution, and accumulation of PP microplastics in the human body. In this study, administration of two particle sizes of PP microplastics (approximately 5 and 10-50 µm) did not lead to any significant changes in several toxicological evaluation parameters, including body weight and pathological examination, compared with the control group in ICR mice. Therefore, the approximate lethal dose and no-observed-adverse-effect level of PP microplastics in ICR mice were established as ≥2000 mg/kg. Furthermore, we manufactured cyanine 5.5 carboxylic acid (Cy5.5-COOH)-labeled fragmented PP microplastics to monitor real-time in vivo biodistribution. After oral administration of the Cy5.5-COOH-labeled microplastics to the mice, most of the PP microplastics were detected in the gastrointestinal tract and observed to be out of the body after 24 h in IVIS Spectrum CT. Therefore, this study provides a new insight into the short-term toxicity, distribution, and accumulation of PP microplastics in mammals.
Topics: Humans; Animals; Mice; Polypropylenes; Microplastics; Plastics; Mice, Inbred ICR; Tissue Distribution; Water Pollutants, Chemical; Mammals
PubMed: 37239816
DOI: 10.3390/ijms24108463 -
The Science of the Total Environment Dec 2022Billions of disposable face masks (i.e., single-use masks) are used and discarded worldwide monthly due to the COVID-19 outbreak. The immethodical disposal of these... (Review)
Review
Billions of disposable face masks (i.e., single-use masks) are used and discarded worldwide monthly due to the COVID-19 outbreak. The immethodical disposal of these polymer-based wastes containing non-biodegradable constituents (e.g., polypropylene) has provoked marked and severe damage to the ecosystem. Meanwhile, their ever-growing usage significantly strains the present-day waste management measures such as landfilling and incineration, resulting in large quantities of used face-covering masks landing in the environment as importunate contaminants. Hence, alternative waste management strategies are crucially demanded to decrease the negative impacts of face mask contamination. In this venue, developing high-yield, effective, and green routes toward recycling or upcycling face mask wastes (FMWs) into value-added materials is of great importance. While existing recycling processes assist the traditional waste management, they typically end up in materials with downgraded physicochemical, structural, mechanical, and thermal characteristics with reduced values. Therefore, pursuing potential economic upcycling processes would be more beneficial than waste disposal and/or recycling processes. This paper reviews recent advances in the FMWs upcycling methods. In particular, we focus on producing value-added materials via various waste conversion methods, including carbonization (i.e., extreme pyrolysis), pyrolysis (i.e., rapid carbonization), catalytic conversion, chemical treatment, and mechanical reprocessing. Generally, the upcycling methods are promising, firming the vital role of managing FMWs' fate and shedding light on the road of state-of-the-art materials design and synthesis.
Topics: Humans; Masks; COVID-19; Ecosystem; Polypropylenes; Recycling; Plastics
PubMed: 36055514
DOI: 10.1016/j.scitotenv.2022.158396 -
Revista Do Colegio Brasileiro de... Dec 2016to compare intraperitoneal adhesion formation in rats when using polypropylene and polypropylene with poliglecaprone meshes.
OBJECTIVE
to compare intraperitoneal adhesion formation in rats when using polypropylene and polypropylene with poliglecaprone meshes.
METHODS
we used twenty male, Wistar rats, divided in two groups. In group 1, the rats received the polypropylene mesh on their right side and the polypropylene with poliglecaprone mesh on their left side. In group 2 the position of the meshes was inverted. After 30 days, we analyzed the presence or not of adhesion formation, including only those over the meshes. The findings undergone an analysis through the Mann-Whitney test, at a level of significance of p≤0.05.
RESULTS
all meshes presented adhesions. We verified that, for the polypropylene meshes, the percentage of their surface covered by adhesions varied from 10.5 to 100%, with an average of 34.07±24.21%, while for the polypropylene with poliglecaprone mesh, the percentage covered by adhesions varied between 8.5% and 100%, with an average of 44.7±32.85% (p=0.12).
CONCLUSION
both meshes lead to adhesion formation, none being superior to the other.
Topics: Animals; Male; Polypropylenes; Prostheses and Implants; Rats; Rats, Wistar; Surgical Mesh; Tissue Adhesions
PubMed: 28273225
DOI: 10.1590/0100-69912016006002 -
Arquivos Brasileiros de Cirurgia... 2017Hernia correction is a routinely performed treatment in surgical practice. The improvement of the operative technique and available materials certainly has been a great...
BACKGROUND
Hernia correction is a routinely performed treatment in surgical practice. The improvement of the operative technique and available materials certainly has been a great benefit to the quality of surgical results. The insertion of prostheses for hernia correction is well-founded in the literature, and has become the standard of treatment when this type of disease is discussed.
AIM
To evaluate two available prostheses: the polypropylene and polypropylene coated ones in an experimental model.
METHODS
Seven prostheses of each kind were inserted into Wistar rats (Ratus norvegicus albinus) in the anterior abdominal wall of the animal in direct contact with the viscera. After 90 days follow-up were analyzed the intra-abdominal adhesions, and also performed immunohistochemical evaluation and videomorphometry of the total, type I and type III collagen. Histological analysis was also performed with hematoxylin-eosin to evaluate cell types present in each mesh.
RESULTS
At 90 days the adhesions were not different among the groups (p=0.335). Total collagen likewise was not statistically different (p=0.810). Statistically there was more type III collagen in the coated polypropylene group (p=0.039) while type I was not different among the prostheses (p=0.050). The lymphocytes were statistically more present in the polypropylene group (p=0.041).
CONCLUSION
The coated prosthesis was not different from the polypropylene one regarding the adhesion. Total and type I collagen were not different among the groups, while type III collagen was more present on the coated mesh. There was a greater number of lymphocytes on the polypropylene mesh.
Topics: Animals; Coated Materials, Biocompatible; Collagen; Equipment Design; Herniorrhaphy; Male; Peritoneal Diseases; Polypropylenes; Postoperative Complications; Rats; Rats, Wistar; Surgical Mesh; Tissue Adhesions
PubMed: 29257839
DOI: 10.1590/0102-6720201700020001 -
Tissue Engineering and Regenerative... Aug 2022Meshes play a crucial role in hernia repair. However, the displacement of mesh inevitably leads to various associated complications. This process is difficult to be...
BACKGROUND
Meshes play a crucial role in hernia repair. However, the displacement of mesh inevitably leads to various associated complications. This process is difficult to be traced by conventional imaging means. The purpose of this study is to create a contrast-enhanced material with high-density property that can be detected by computed tomography (CT).
METHODS
The contrast-enhanced monofilament was manufactured from barium sulfate nanoparticles and medical polypropylene (PP/Ba). To characterize the composite, stress tensile tests and scanning electron microscopy (SEM) was performed. Toxicity and biocompatibility of PP/Ba materials was verified by in vitro cellular assays. Meanwhile, the inflammatory response was tested by protein adsorption assay. In addition, an animal model was established to demonstrate the long-term radiographic effect of the composite material in vivo. Subsequent pathological tests confirmed its in vivo compatibility.
RESULTS
The SEM revealed that the main component of the monofilament is carbon. In vitro cell experiments demonstrated that novel material does not affect cell activity and proliferation. Protein adsorption assays indicated that the contrast-enhanced material does not cause additional inflammatory responses. In addition, in vivo experiments illustrated that PP/Ba mesh can be detected by CT and has good in vivo compatibility.
CONCLUSION
These results highlight the excellent biocompatibility of the contrast-enhanced material, which is suitable for human abdominal wall tissue engineering.
Topics: Animals; Hernia; Humans; Materials Testing; Polypropylenes; Prostheses and Implants; Surgical Mesh
PubMed: 35612710
DOI: 10.1007/s13770-022-00460-6 -
Molecules (Basel, Switzerland) Oct 2022Since the outbreak of COVID-19, face masks have been introduced in the complex strategy of infection prevention and control. Face masks consist of plastic polymers and...
Since the outbreak of COVID-19, face masks have been introduced in the complex strategy of infection prevention and control. Face masks consist of plastic polymers and additives such as phthalates. The aim of this study was to evaluate the migration of microplastics (MP) and phthalates from face masks to water. Four types of masks including FFP2 masks and surgical were studied. Masks were first characterized to determine the different layers and the material used for their fabrication. Then, masks were cut into 20 pieces of 0.5 cm, including all their layers, placed in water, and the migration of MP and phthalates was evaluated according to the conditions stated in EU Regulation No 10/2011 on plastic materials and articles intended to come into contact with food. For MP, the morphological analysis (shape, dimension, particle count) was performed using a stereomicroscope, while the identification of both masks and MP released was conducted using μ-Fourier-transform infrared spectroscopy (µ-FT-IR). Migration of phthalates was assessed by ultra-high-performance liquid chromatography coupled to triple quadrupole mass spectrometer (UPLC-MS/MS). Face masks analyzed in the present study were made of atactic polypropylene (PP) as stated by the manufacturer. The μ-FT-IR confirmed that PP and polyamide (PA) were released as fragments, while both PP and polyester (PES) were released as fibers. In addition, 4 phthalates were identified at concentrations between 2.34 and 21.0 µg/mask. This study shows that the migration study can be applied to evaluate the potential release of MP and phthalates from face masks to water and could give a hint for the potential impact of their incorrect disposal on the aquatic resources.
Topics: Humans; Microplastics; Plastics; Masks; Water; Spectroscopy, Fourier Transform Infrared; Polypropylenes; Nylons; Chromatography, Liquid; COVID-19; Tandem Mass Spectrometry; Polyesters
PubMed: 36296451
DOI: 10.3390/molecules27206859 -
International Journal of Molecular... Oct 2022During the production of polymer-grade propylene, different processes are used to purify this compound and ensure that it is of the highest quality. However, some...
During the production of polymer-grade propylene, different processes are used to purify this compound and ensure that it is of the highest quality. However, some impurities such as acetylene and methyl acetylene are difficult to remove, and some of these impurities may be present in the propylene used to obtain polypropylene, which may have repercussions on the process. This study evaluates the impact of these acetylene and methyl acetylene impurities on the productivity of the polypropylene synthesis process and on the mechanical and thermal properties of the material obtained through the synthesis of eight samples with different concentrations of acetylene and eight samples with different concentrations of acetylene. We discovered that for the first concentrations of both acetylene (2 and 3 ppm) and methyl acetylene (0.03 and 0.1), the MFI, thermal recording, and mechanical properties of the resin were unaffected by the variation of the fluidity index, thermal degradation by TGA, and mechanical properties such as resistance to tension, bending, and impact. However, when the concentration exceeded 14 ppm for methyl acetylene and 12 ppm for acetylene, the resistance of this resin began to decrease linearly. Regarding production, this was affected by the first traces of acetylene and methyl acetylene progressively decreasing.
Topics: Acetylene; Polypropylenes; Alkynes; Polymers
PubMed: 36293003
DOI: 10.3390/ijms232012148 -
Environmental Pollution (Barking, Essex... Jun 2022Plastics are utilised globally but are of environmental concern due to their persistence. The global presence of microplastics (particles <5 mm in all dimensions) in...
Plastics are utilised globally but are of environmental concern due to their persistence. The global presence of microplastics (particles <5 mm in all dimensions) in freshwater environments is increasingly reported, as has the presence of cyanobacterial toxins, including the microcystins. We elucidated the potential role of microplastics as a vector for eight microcystin analogues. Two sizes of polypropylene (PP) and polyethylene terephthalate (PET) microparticles were evaluated. The median particle size distribution (D) was 8-28 μm for small particles, and 81-124 μm for large particles. Additionally, microcystin-LR and -LF were evaluated individually using small PP and PET to elucidate the adsorption behaviour in the absence of competition. Microcystin hydrophobicity, polymer material, and particle size were key factors influencing adsorption to the plastic microparticles. The small size PP microparticles demonstrated a high affinity for the 8 microcystin analogues. The proportion of microcystin adsorbed onto the small particles of PP after 48 h contact was between 83 and 100%, depending on the analogue. Of all analogues investigated, only microcystin-LW and -LF adsorbed onto the larger sized PP and PET microparticles. Individually, greater amounts of MC-LF adsorbed onto the small PET (19%) compared to when it was present in the mixture of microcystins (11%). While MC-LR did not adsorb onto small PET microparticles in the mixture, 5% adsorption was observed when individually in contact with small PET microparticles. The results demonstrated that microplastics can adsorb eight different microcystin analogues and that more hydrophobic analogues are more likely to adsorb than less hydrophobic analogues.
Topics: Adsorption; Cyanobacteria Toxins; Microcystins; Microplastics; Plastics; Polyethylene Terephthalates; Polypropylenes; Water Pollutants, Chemical
PubMed: 35283205
DOI: 10.1016/j.envpol.2022.119135 -
Molecules (Basel, Switzerland) Dec 2011Transglutaminase (TGase) was cross-linked with glutaraldehyde, and cross-linked crystalline transglutaminase was immobilized on a polypropylene microporous membrane by...
Transglutaminase (TGase) was cross-linked with glutaraldehyde, and cross-linked crystalline transglutaminase was immobilized on a polypropylene microporous membrane by UV-induced grafting. Immobilized enzyme activity were calculated to be 0.128 U/cm² polypropylene microporous membrane. The microstructure and enzyme characteristics of free, cross-linked and immobilized transglutaminase were compared. The optimum temperature of free transglutaminase was determined to be approximately 40 °C, while cross-linking and immobilization resulted in an increase to approximately 45 °C and 50 °C. At 60 °C, immobilized, cross-linked and free transglutaminase retained 91.7 ± 1.20%, 63.2 ± 1.05% and 37.9 ± 0.98% maximum activity, respectively. The optimum pH was unaffected by the state of transglutaminase. However, the thermal and pH stabilities of cross-linked and immobilized transglutaminase were shown to increase.
Topics: Cross-Linking Reagents; Enzyme Stability; Enzymes, Immobilized; Hydrogen-Ion Concentration; Membranes, Artificial; Polypropylenes; Porosity; Temperature; Transglutaminases
PubMed: 22143573
DOI: 10.3390/molecules161210046