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Journal of Functional Biomaterials Jun 2023Medical gloves, along with masks and gowns, serve as the initial line of defense against potentially infectious microorganisms and hazardous substances in the health... (Review)
Review
Medical gloves, along with masks and gowns, serve as the initial line of defense against potentially infectious microorganisms and hazardous substances in the health sector. During the COVID-19 pandemic, medical gloves played a significant role, as they were widely utilized throughout society in daily activities as a preventive measure. These products demonstrated their value as important personal protection equipment (PPE) and reaffirmed their relevance as infection prevention tools. This review describes the evolution of medical gloves since the discovery of vulcanization by Charles Goodyear in 1839, which fostered the development of this industry. Regarding the current market, a comparison of the main properties, benefits, and drawbacks of the most widespread types of sanitary gloves is presented. The most common gloves are produced from natural rubber (NR), polyisoprene (IR), acrylonitrile butadiene rubber (NBR), polychloroprene (CR), polyethylene (PE), and poly(vinyl chloride) (PVC). Furthermore, the environmental impacts of the conventional natural rubber glove manufacturing process and mitigation strategies, such as bioremediation and rubber recycling, are addressed. In order to create new medical gloves with improved properties, several biopolymers (e.g., poly(vinyl alcohol) and starch) and additives such as biodegradable fillers (e.g., cellulose and chitin), reinforcing fillers (e.g., silica and cellulose nanocrystals), and antimicrobial agents (e.g., biguanides and quaternary ammonium salts) have been evaluated. This paper covers these performance-enhancing materials and describes different innovative prototypes of gloves and coatings designed with them.
PubMed: 37504844
DOI: 10.3390/jfb14070349 -
Gels (Basel, Switzerland) Jul 2023Three-dimensional and porous polypyrrole (PPy) aerogels were prepared using a facile two-step procedure in which cryogels were synthesized via the cryopolymerization of...
Three-dimensional and porous polypyrrole (PPy) aerogels were prepared using a facile two-step procedure in which cryogels were synthesized via the cryopolymerization of pyrrole with iron (III) chloride in the presence of supporting water-soluble polymers (poly(-vinylpyrrolidone), poly(vinyl alcohol), gelatin, methylcellulose or hydroxypropylcellulose), followed by freeze-drying to obtain aerogels. The choice of supporting polymers was found to affect the morphology, porosity, electrical conductivity, and mechanical properties of PPy aerogels. PPy aerogels were successfully used as adsorbents to remove toxic Cr(VI) ions from aqueous solutions.
PubMed: 37504461
DOI: 10.3390/gels9070582 -
Polymers Jul 2023The recycling of non-metallic printed circuit boards (NMPCB) as a filler in poly(vinyl chloride) (PVC) composite would help to encourage the use of waste NMPCB, thus,...
The recycling of non-metallic printed circuit boards (NMPCB) as a filler in poly(vinyl chloride) (PVC) composite would help to encourage the use of waste NMPCB, thus, reducing some environmental concerns with regard to e-waste. The objective of this study was to comprehensively evaluate the effect of different interfacial agents, namely polypropylene grafted maleic anhydride (PP-g-MAH) and ϒ-aminopropyltriethoxy silane (ATPS) on the morphology and properties of PVC/NMPCB composites. A PVC/NMPCB composite was prepared by melt compounding with varying amounts of NMPCB ranging between 10, 20 and 30 wt.%. Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) analysis revealed the interactions between PVC and NMPCB when using both PP-g-MAH and ATPS interfacial agent. The properties and morphology of PVC/NMPCB composites were significantly dependent on the interfacial agent treated on the NMPCB surface. The phase morphology and mechanical properties of PVC/NMPCB composites (30 wt.% of NMPCB) were improved and the result also indicated that the higher compatibility of composites with ATPS as an interfacial agent led to our obtaining the maximum Young's modulus of 484 MPa. The dynamic mechanical analysis revealed the interaction at the interface, with the T shifting to a lower temperature in the presence of PP-g-MAH and strong interfacial adhesion noted with the improved T in the presence of the ATPS interfacial agent. Further evidence of the improved interaction was observed with the increment in density in the presence of ATPS when compared with PP-g-MAH in PVC/NMPCB composite. Hence, of the two interfacial agents, ATPS showed itself to be more effective when employed as an interfacial agent for NMPCB in PVC composite for industry.
PubMed: 37447583
DOI: 10.3390/polym15132938 -
Polymers Jun 2023Polyesters with a high glass transition temperature above 130 °C were obtained from limonene oxide (LO) or vinylcyclohexene oxide (VCHO) and phthalic anhydride (PA) in...
Polyesters with a high glass transition temperature above 130 °C were obtained from limonene oxide (LO) or vinylcyclohexene oxide (VCHO) and phthalic anhydride (PA) in the presence of commercial salen-type complexes with different metals-Cr, Al, and Mn-as catalysts in combination with 4-(dimethylamino) pyridine (DMAP), bis-(triphenylphosphorydine) ammonium chloride (PPNCl), and bis-(triphenylphosphoranylidene)ammonium azide (PPNN) as cocatalysts via alternating ring-opening copolymerization (ROCOP). The effects of the time of precontact between the catalyst and cocatalyst and the polymerization time on the productivity, molar mass (), and glass transition temperature () were evaluated. The polyesters were characterized by a molar mass () of up to 14.0 kg/mol, a narrow dispersity of up to 136 °C, and low (<3 mol%) polyether units. For poly(LO--PA) copolymers, biodegradation tests were performed according to ISO 14851 using the respirometric biochemical oxygen demand method. Moreover, the vinyl double bond present in the poly(LO--PA) copolymer chain was functionalized using three different thiols, methyl-3-mercaptopropionate, isooctyl-3-mercaptopropionate, and butyl-3-mercaptopropionate, via a click chemistry reaction. The thermal properties of poly(LO--PA), poly(VCHO--PA) and thiol-modified poly(LO--PA) copolymers were extensively studied by DSC and TGA. Some preliminary compression molding tests were also conducted.
PubMed: 37447447
DOI: 10.3390/polym15132801 -
ACS Sustainable Chemistry & Engineering Jun 2023In the last two decades, the use of phthalates has been restricted worldwide due to their well-known toxicity. Nonetheless, phthalates are still widely used for their...
In the last two decades, the use of phthalates has been restricted worldwide due to their well-known toxicity. Nonetheless, phthalates are still widely used for their versatility, high plasticization effect, low cost, and lack of valuable alternatives. This study presents the fully bio-based and versatile glycerol trilevulinate plasticizer (GT) that was obtained by the valorization of glycerol and levulinic acid. The mild-conditions and solvent-free esterification used to synthesize GT was optimized by investigating the product by Fourier transform infrared and NMR spectroscopy. An increasing content of GT, from 10 to 40 parts by weight per hundred parts of resin (phr), was tested with poly(vinyl chloride), poly(3-hydroxybutyrate), poly(3-hydroxybutyrate--3-hydroxyvalerate), poly(lactic acid), and poly(caprolactone), which typically present complicated processability and/or mechanical properties. GT produced a significant plasticization effect on both amorphous and semicrystalline polymers, reducing their glass-transition temperature and stiffness, as observed by differential scanning calorimetry measurements and tensile tests. Remarkably, GT also decreased both the melting temperature and crystallinity degree of semicrystalline polymers. Furthermore, GT underwent enzyme-mediated hydrolysis to its initial constituents, envisioning a promising prospective for environmental safety and upcycling. Furthermore, 50% inhibitory concentration (IC) tests, using mouse embryo fibroblasts, proved that GT is an unharmful alternative plasticizer, which makes it potentially applicable in the biomedical field.
PubMed: 37389191
DOI: 10.1021/acssuschemeng.3c01536 -
Membranes May 2023A unique facilitation on the transport flux of Cu(II) was investigated by using modified polymer inclusion membranes (PIMs). LIX84I-based polymer inclusion membranes...
A unique facilitation on the transport flux of Cu(II) was investigated by using modified polymer inclusion membranes (PIMs). LIX84I-based polymer inclusion membranes (LIX-based PIMs) using poly(vinyl chloride) (PVC) as support, 2-nitrophenyl octyl ether (NPOE) as plasticizer and Lix84I as carrier were modified by reagents with different polar groups. The modified LIX-based PIMs showed an increasing transport flux of Cu(II) with the help of ethanol or Versatic acid 10 modifiers. The metal fluxes with the modified LIX-based PIMs were observed varying with the amount of modifiers, and the transmission time was cut by half for the modified LIX-based PIM cast with Versatic acid 10. The physical-chemical characteristics of the prepared blank PIMs with different Versatic acid 10 were further characterized by using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), contract angle measurements and electro-chemical impedance spectroscopy (EIS). The characterization results indicated that the modified LIX-based PIMs cast with Versatic acid 10 appeared to be more hydrophilic with increasing membrane dielectric constant and electrical conductivity that allowed better accessibility of Cu(II) across PIMs. Hence, it was deduced that hydrophilic modification might be a potential method to improve the transport flux of the PIM system.
PubMed: 37367754
DOI: 10.3390/membranes13060550 -
FEMS Microbes 2022Few strains of harbour and express the vinyl chloride reductase (VcrA) that catalyzes the dechlorination of vinyl chloride (VC), a carcinogenic soil and groundwater...
Few strains of harbour and express the vinyl chloride reductase (VcrA) that catalyzes the dechlorination of vinyl chloride (VC), a carcinogenic soil and groundwater contaminant. The operon is found on a Genomic Island (GI) and, therefore, believed to participate in horizontal gene transfer (HGT). To try to induce HGT of the -GI, we blended two enrichment cultures in medium without ammonium while providing VC. We hypothesized that these conditions would select for a mutant strain of that could both fix nitrogen and respire VC. However, after more than 4 years of incubation, we found no evidence for HGT of the -GI. Rather, we observed VC-dechlorinating activity attributed to the trichloroethene reductase TceA. Sequencing and protein modelling revealed a mutation in the predicted active site of TceA, which may have influenced substrate specificity. We also identified two nitrogen-fixing strains in the KB-1 culture. The presence of multiple strains of with distinct phenotypes is a feature of natural environments and certain enrichment cultures (such as KB-1), and may enhance bioaugmentation success. The fact that multiple distinct strains persist in the culture for decades and that we could not induce HGT of the -GI suggests that it is not as mobile as predicted, or that mobility is restricted in ways yet to be discovered to specific subclades of .
PubMed: 37332513
DOI: 10.1093/femsmc/xtac021 -
Neurology India 2023Toxic encephalopathy is a spectrum of central nervous system disorders caused by exposure to toxins, especially from occupational workplace. Polyvinylchloride (PVC) is a...
BACKGROUND
Toxic encephalopathy is a spectrum of central nervous system disorders caused by exposure to toxins, especially from occupational workplace. Polyvinylchloride (PVC) is a synthetic chemical polymer that is used widely in daily activities of living. PVC is produced by polymerization of monomer units of vinyl chloride. Its manufacturing requires multiple procedures and additives for heat and light stabilization involving heavy metals.
OBJECTIVE
In this novel case series, we present the diverse clinical presentation of 10 patients, working in plastic recycling factory having inhalational exposure to PVC fumes, manifesting as acute toxic encephalopathy.
MATERIALS AND METHODS
All the patients were screened for the causes of acute encephalopathy including heavy metals, methanol poisoning, and organotins along with arterial blood gas analysis, brain imaging, and electroencephalogram. Memory loss, confusion, vertigo, headache, and nausea were complained in all the patients while seizure occurred in three patients. Neurocognitive status was grossly impaired in all the patients. Metabolic acidosis in presence of hyponatremia and/or hypokalemia was observed in nine cases. Five of the patients were having evidence of white matter involvement in brain imaging. The screening for heavy metal, methanol, and organotin were negative. Hemodialysis was done in six patients. Recovery was good in everyone and the average discharge was by 10.8 days (range: 2-25 days). All the patients were symptom-free at 3-months follow-up.
CONCLUSION
Early suspicion and aggressive management can have favorable outcome in PVC toxic encephalopathy. Occupational hazards due to PVC toxicity are increasing in the present industrial era but it is very less identified.
Topics: Humans; Polyvinyl Chloride; Methanol; Occupational Exposure; Metals, Heavy; Brain Diseases; Neurotoxicity Syndromes
PubMed: 37322752
DOI: 10.4103/0028-3886.378675 -
Journal of Contaminant Hydrology Jul 2023The degradation of trichloroethylene (TCE) vapors by zero-valent Iron-Copper (Fe-Cu) and Iron-Nickel (Fe-Ni) bimetals with 1%, 5% and 20% weight content (%wt) of Cu or...
The degradation of trichloroethylene (TCE) vapors by zero-valent Iron-Copper (Fe-Cu) and Iron-Nickel (Fe-Ni) bimetals with 1%, 5% and 20% weight content (%wt) of Cu or Ni was tested in anaerobic batch vapor systems carried out at ambient room temperature (20 ± 2 °C) under partially saturated conditions. The concentrations of TCE and byproducts were determined at discrete reaction time intervals (4 h-7 days) by analyzing the headspace vapors. In all the experiments, up to 99.9% degradation of TCE in the gas phase was achieved after 2-4 days with zero-order TCE degradation kinetic constants in the range of 134-332 g md. Fe-Ni showed a higher reactivity towards TCE vapors compared to Fe-Cu, with up to 99.9% TCE dechlorination after 2 days of reaction, i.e., significantly higher than zero-valent iron alone that in previous studies was found to achieve comparable TCE degradation after minimum 2 weeks of reaction. The only detectable byproducts of the reactions were C-C hydrocarbons. Neither vinyl chloride or dichloroethylene peaks were detected in the tested conditions above their method quantification limits that were in the order of 0.01 g m. In view of using the tested bimetals in horizontal permeable reactive barriers (HPRBs) placed in the unsaturated zone to treat chlorinated solvent vapors emitted from contaminated groundwater, the experimental results obtained were integrated into a simple analytical model to simulate the reactive transport of vapors through the barrier. It was found that an HPRB of 20 cm could be potentially effective to ensure TCE vapors reduction.
Topics: Trichloroethylene; Copper; Water Pollutants, Chemical; Solvents; Iron
PubMed: 37301040
DOI: 10.1016/j.jconhyd.2023.104204