Long-Term Effect of Ultraviolet Irradiation on Poly(vinyl chloride) Films Containing Naproxen Diorganotin(IV) Complexes.

As poly(vinyl chloride) (PVC) photodegrades with long-term exposure to ultraviolet radiation, it is desirable to develop methods that enhance the photostability of PVC. In this study, new aromatic-rich diorganotin(IV) complexes were tested as photostabilizers in PVC films. The diorganotin(IV) complexes were synthesized in 79-86% yields by reacting excess naproxen with tin(IV) chlorides. PVC films containing 0.5 wt % diorganotin(IV) complexes were irradiated with ultraviolet light for up to 300 h, and changes within the films were monitored using the weight loss and the formation of specific functional groups (hydroxyl, carbonyl, and polyene). In addition, changes in the surface morphologies of the films were investigated. The diorganotin(IV) complexes enhanced the photostability of PVC, as the weight loss and surface roughness were much lower in the films with additives than in the blank film. Notably, the dimethyltin(IV) complex was the most efficient photostabilizer. The polymeric film containing this complex exhibited a morphology of regularly distributed hexagonal pores, with a honeycomb-like structure-possibly due to cross-linking and interactions between the additive and the polymeric chains. Various mechanisms, including direct absorption of ultraviolet irradiation, radical or hydrogen chloride scavenging, and polymer chain coordination, could explain how the diorganotin(IV) complexes stabilize PVC against photodegradation.

Occupational exposures at a polyvinyl chloride production facility are associated with significant changes to the plasma metabolome.

BACKGROUND: Occupational vinyl chloride (VC) exposures have been associated with toxicant-associated steatohepatitis and liver cancer. Metabolomics has been used to clarify mode of action in drug-induced liver injury but has not been performed following VC exposures. METHODS: Plasma samples from 17 highly exposed VC workers without liver cancer and 27 unexposed healthy volunteers were obtained for metabolite extraction and GC/MS and LC/MS2 analysis. Following ion identification/quantification, Ingenuity pathway analysis was performed. RESULTS: 613 unique named metabolites were identified. Of these, 189 metabolites were increased in the VC exposure group while 94 metabolites were decreased. Random Forest analysis indicated that the metabolite signature could separate the groups with 94% accuracy. VC exposures were associated with increased long chain (including arachidonic acid) and essential (including linoleic acid) fatty acids. Occupational exposure increased lipid peroxidation products including monohydroxy fatty acids (including 13-HODE); fatty acid dicarboxylates; and oxidized arachidonic acid products (including 5,9, and 15-HETE). Carnitine and carnitine esters were decreased, suggesting peroxisomal/mitochondrial dysfunction and alternate modes of lipid oxidation. Differentially regulated metabolites were shown to interact with extracellular-signal-regulated kinase 1/2 (ERK1/2), Akt, AMP-activated protein kinase (AMPK), and the N-Methyl-d-aspartate (NMDA) receptor. The top canonical pathways affected by occupational exposure included tRNA charging, nucleotide degradation, amino acid synthesis/degradation and urea cycle. Methionine and homocysteine was increased with decreased cysteine, suggesting altered 1-carbon metabolism. CONCLUSIONS: Occupational exposure generated a distinct plasma metabolome with markedly altered lipid and amino acid metabolites. ERK1/2, Akt, AMPK, and NMDA were identified as protein targets for vinyl chloride toxicity.

Mercury transformation and distribution across a polyvinyl chloride (PVC) production line in China.

The production of polyvinyl chloride (PVC) via the calcium carbide process utilizes a catalyst containing large amounts of mercury (Hg) and is therefore one of the most important sources of anthropogenic Hg in China. To measure the emission of Hg from PVC production, we established a flowchart for the calcium carbide process, for which we quantified the Hg content of the material/product at each step. Results indicated that 71.5% of the total Hg (Hg(T)) was lost from the catalyst, most of which was recovered by the Hg remover, accounting for 46.0% of the total Hg (Hg(T)). We determined that 3.7% of the Hg(T) was released into the environment, mostly in solid wastes and byproducts such as hydrochloric acid. Furthermore, no Hg has been detected in the PVC end product. However, we were only able to account for 78.1% of the Hg across the whole system, leaving 21.7% unaccounted for in the mass balance. A rough estimation indicates that most of the "missing" Hg had accumulated in deposits on the inner surface of converters and downstream pipelines; however, the emission to the atmosphere was ≤ 1% of the Hg(T). For a PVC production line equipped with a Hg remover, emissions of Hg to the atmosphere have been estimated to be 4.9 g per tonne PVC. Currently, almost all calcium carbide facilities have been equipped with a Hg remover, which may reduce the release of Hg in China by ∼ 500 t/year.

Cellulose-based sustainable polymers: state of the art and future trends.

Nowadays, nearly all polymeric materials are produced from crude oil-derived monomers. With the steadily increasing demand for oil-based products and their decreasing availability in the near future, one of the main challenges of mankind is the replacement of crude oil as raw material by renewable resources such as biomass. So far, only a few polymers are available derived directly from cellulose as a main component of biomass by regeneration. On the other hand, a significant potential lies in the production of polymers from cellulose-derived monomers. A huge variety of different monomers is already available by convenient catalytic processes. This feature article focuses on the current status of mono- and resulting polymers derived either directly from cellulose processing and regeneration or by catalytic conversion to a number of monomers for the production of novel polymers and co-polymers.

Sebacic and succinic acid derived plasticised PVC for the inhibition of biofouling in its initial stages.

AIM: In this work, we report the use of plasticized poly vinylchloride (PVC) as a potential antifouling coating material. The materials contain a variety of sebacic and succinic acid-derived plasticisers providing a variation in molecular shape and structure; diethyl succinate (DESn), di-(2-ethylhexyl sebacate) (DEHS), dibutyl sebacate (DBS), and diethyl sebacate (DES). Each plasticiser from the sebacate group possessed the same basic C10H16O4 moiety with varied dialkyl terminated groups, affording a different range of homologous series plasticisers. This work investigates whether branching of the side substituted alkyl chains on each plasticiser molecule affects microorganism attachment and subsequent fouling. MATERIALS AND METHODS: The plasticized polymers are spin coated to create thin films for testing. In order to determine the antifouling capacity of the materials, the polymer coatings underwent a series of analyses for biomass determination, glycocalyx production, and protein and carbohydrate adsorption. Topological and morphological characterization was performed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). RESULTS: After a 7 day laboratory biofouling study it was found that the plasticisers with increased alkyl branching, DESN, and DEHS revealed the greatest degree of prevention of microorganism colonization and attachment thus significantly reducing the initial formation of biofilms by up to 65% in some biofouling assays when compared to the uPVC blank.

SMART tubing presents an increased risk of disconnection during extracorporeal circulation.

A number of products exhibiting biocompatible features have been developed for use in extracorporeal blood circuits during cardiopulmonary bypass procedures. While attention has been focused on biocompatibility features of the blood-circuit interface, a number of issues applicable in clinical use of these circuits have arisen. Surface Modifying Additive Technology (SMART; Cobe Cardiovascular, Arvarda, CO) is one such technology. In this product, the structure of normal polyvinylchloride (PVC) tubing is altered through the blending of two copolymers to give a more biocompatible blood to plastic interface. In this study, we examined the in vitro mechanical ability of random samples (n = 10) of SMART and standard PVC tubing to withstand axial tension when the tubing was placed over a single barb of a connector. The tension required to remove the SMART tubing from the connector (83.3 +/- 7.3 [SD] N), was significantly less than standard PVC tubing (115.6 +/- 15.9 N; p < .0001, unpaired t test). The SMART tubing exhibited a 28% reduction in tubing to connector adhesion, which may have a significant effect on extracorporeal circuit disconnection and overall patient safety.

Diffusion of residual monomer in polymer resins.

A simplified mathematical model which made use of Fick's laws of diffusion written in spherical coordinates was developed to describe the rate of diffusion of residual monomers from polymer resins. The properties of the monomer-polymer system which influenced the amount of monomer remaining in the polymer as a function of time were the diffusivity and solubility of the monomer in the polymer, and the particle size of the polymer resin. This model was used to analyze literature data on the diffusion of residual vinyl chloride monomer in polyvinyl chloride resins made by the suspension process. It was concluded that particle size of the resin was a significant parameter which should be taken advantage of in process equipment designed to remove residual monomer from PVC resins. The diffusivity of the monomer in the polymer was a function of the solubility of the monomer in the polymer. Monomer solubility can be determined from Henry's law. It was suggested that this model could be adapted to describe diffusion of monomers from any monomer-polymer system, and would be a useful approach to modeling the transport of nonreactive chemical additives from plastics.

Industrial preparation of poly(vinyl chloride).

Vinyl chloride (VCM) is unloaded from railroad tank cars or tank trucks into pressurized storage spheres. VCM, emulsifiers, and catalysts are metered into polymerization vessels wherein PVC is produced through a chemical reaction in an aqueous medium under controlled conditions of temperature and pressure. After the reaction reaches a predetermined completion, the contents are transferred to a secondary vessel wherein steam is injected and the VCM containing vapors are pumped to a recovery system. The VCM-containing vapors are compressed, cooled, condensed, decanted, and recycled to the process for reuse. The stripped PVC resin water slurry is then pumped to blending tanks where the batches from multiple reaction vessels are blended for product uniformity. From the plant tanks the PVC resin water slurry is pumped to a dewatering centrifuge, where approximately 90% of the water is removed and subsequently discharged to the industrial sewer system. The PVC resin wet cake is conveyed from the centrifuge to a flash dryer where essentially all the remaining water is removed. At this point, the dry resin is buoyant in an air stream and enters a two-stage collection system for separation of conveying air. The PVC resin is then screened and air-conveyed to storage for bulk shipment, compounding, or bagging.

Preparation and characterization of hydrophobic polymeric films that are thromboresistant via nitric oxide release.

The preparation of hydrophobic polymer films (polyurethane and poly(vinyl chloride)) containing nitric oxide (NO)-releasing diazeniumdiolate functions is reported as a basis for improving the thromboresistivity of such polymeric materials for biomedical applications. Several different approaches for preparing NO-releasing polymer films are presented, including: (1) dispersion of diazeniumdiolate molecules within the polymer matrix; (2) covalent attachment of the diazeniumdiolate to the polymer backbone; and (3) ion-pairing of a diazeniumdiolated heparin species to form an organic soluble complex that can be blended into the polymer. Each approach is characterized in terms of NO release rates and in vitro biocompatibility. Results presented indicate that the polymer films prepared by each approach release NO for variable periods of time (10-72 h), although they differ in the mechanism, location and amount of NO released. In vitro platelet adhesion studies demonstrate that the localized NO release may prove to be an effective strategy for improving blood compatibility of polymer materials for a wide range of medical devices.

Vasculitic purpura in vinyl chloride disease: a case report.

Vinyl chloride (VC), a volatile substance mostly used for polyvinyl chloride (PVC) synthesis, is a systemic toxicant particularly noxious to endothelium. Angiosarcoma of the liver, Raynaud's phenomenon, scleroderma-like lesions, acroosteolysis and neuritis are known to be typical vinyl chloride-associated manifestations (VC disease). A so far unknown feature of the disease is purpura. This was first observed by the authors in a worker of a PVC-producing plant. The skin eruption was characterized by small purpuric maculae with tiny, palpable spots and papulae, mostly concentrated on the lower part of the legs, changing into bullae, pustules and crusts and tending to spontaneous regression after withdrawal from VC exposure. A skin biopsy revealed marked inflammatory reaction with a mostly lymphocytic and histiocytic infiltration around and in the walls of dermal arterioles. The finding of increased circulating immune complexes and anti-smooth muscle autoantibodies strengthens the hypothesis that immunologic changes play a role in the appearance of "vinylic purpura."

Synthesis of biologically active and photostable rigid poly(vinyl chloride).

N,N-Dimethyl-N'-(6-oxo-2-thioxo-1H-pyrimidine-4-yl)formamidine has been synthesized and introduced as a substituent in poly(vinyl chloride) (PVC) chains via a chemical reaction. Both the dimethyl derivative and the modified PVC have been characterized via spectroscopic analyses and their biological activities have been evaluated. Both IR and (1) H NMR spectral data confirm the incorporation of the newly prepared bioactive dimethyl pyrimidine derivative in the polymeric chains. The dimethyl pyrimidine derivative has exhibited good antibacterial and antifungal activities. The modified PVC shows higher antibacterial effects than that of the blank one. Photostabilizing efficiency of the modified PVC is determined by measuring the changes that occurred in the molecular weights of modified PVC samples after UV irradiation using the gel permeation chromatography technique. The extent of discoloration of the photodegraded modified PVC samples has also been measured. The results have been compared with that of the blank PVC and that of the PVC stabilized with phenyl salicylate as a reference UV absorber. The lower decrease in the values of weight average molecular weight, M(w) , at the first stages of UV irradiation and the absence of crosslinking at the latter stages of irradiation confirms the photostability of the modified PVC. The extent of discoloration of the modified sample is also decreased when compared with the blank and stabilized PVC samples.

Novel thermally stable poly(vinyl chloride) composites for sulfate removal.

BaCO(3) dispersed PVC composites were prepared through a polymer re-precipitation method. The composites were tested for sulfate removal using rapid small scale column test (RSSCT) and found to significantly reduce sulfate concentration. The method was extended to synthesize barium carbonate-loaded silica aero-gels-polyvinyl chloride (PVC) polymer composites. The PVC composites were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray mapping, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and inductively coupled plasma mass spectrometry (ICP-MS) analysis. The method has advantages over conventional sulfate precipitation (sulfate removal process) using BaCO(3) wherein clogging of the filter can be avoided. The method is environmentally friendly and does not interfere with natural organic matter as the conventional resin does. Some of the composites were thermally more stable as compared with the pure PVC discussed in the literature.

Fabrication of a novel iron(III)-PVC membrane sensor based on a new 1,1'-(iminobis(methan-1-yl-1-ylidene))dinaphthalen-2-ol synthetic ionophore for direct and indirect determination of free iron species in some biological and non-biological samples.

In this novel, the iron(III)-PVC membrane sensor was investigated based on a new 1,1'-(iminobis(methan-1-yl-1-ylidene))dinaphthalen-2-ol (IBMYD) synthetic ionophore as a suitable carrier. The best performance was observed for the membrane composition including 33.0% PVC, 65.0% TEHP, 1.0% NaTPB and 1.0% ionophore. The electrode displayed a linear potential response over a wide concentration range from 1.0 x 10(-7) to 1.0 x 10(-1)mol L(-1), with a detection limit of 5.0 x 10(-8)mol L(-1) and a good Nernstian slope of 19.9+/-0.3 mV decade(-1). The sensor possessed some advantages such as short conditioning time, very fast response time (<12s) and especially good discriminating ability towards Fe(III) ions over a wide variety of alkali, alkaline earth, transition, and heavy metal ions. The potential response of the proposed sensor was independent of the pH of the test solution, in the pH working range from 3.0 to 6.3. The fabricated electrode was applied for at least 2 months, without any measurable divergence in the potential characteristics. The optimized sensor was used successfully for direct and indirect determination of free iron species in some different synthetic and real samples with satisfactory results.

Development of electrochemical sensors for nano scale Tb(III) ion determination based on pendant macrocyclic ligands.

The two macrocyclic pendant ligands 3,4,5:12,13,14-dipyridine-2,6,11,15-tetramethyl-1,7,10,16-tetramethylacrylate-1,4,7,10,13,16-hexaazacyclooctadeca-3,13-di ene (L(1)) and 3,4,5:12,13,14-dipyridine-2,6,11,15-tetramethyl-1,7,10,16-tetra(2-cyano ethane)-1,4,7,10,13,16-hexaazacyclooctadeca-3,13-diene (L(2)) have been synthesized and explored as neutral ionophores for preparing poly(vinylchloride) (PVC) based membrane sensors selective to Tb(III) ions. Effects of various plasticizers and anion excluders were studied in detail and improved performance was observed. The best performance was obtained for the membrane sensor having a composition of L(1): PVC:1-CN:NaTPB in the ratio of 6: 32: 58: 4 (w/w; mg). The performance of the membrane based on L(1) was compared with polymeric membrane electrode (PME) as well as with coated graphite electrode (CGE). The electrodes exhibit Nernstian slope for Tb(3+) ions with limits of detection of 3.4 x 10(-8)mol L(-1) for PME and 5.7 x 10(-9)mol L(-1) for CGE. The response time for PME and CGE was found to be 10s and 8s, respectively. The potentiometric responses are independent of the pH of the test solution in the pH range 3.0-7.5 for PME and 2.0-8.5 for CGE. The CGE has found to work satisfactorily in partially non-aqueous media upto 30% (v/v) content of methanol, ethanol and 20% (v/v) content of acetonitrile and could be used for a period of 5 months. The CGE was used as indicator electrode in the potentiometric titration of Tb(3+) ions with EDTA and in determination of fluoride ions in various samples. It can also be used in direct determination of Tb(3+) ions in tap water and various binary mixtures with quantitative results.

[Why must we manufacture vinyl chloride and polyvinyl chloride?]. / Warum müssen Vinylchlorid und Polyvinylchlorid hergestellt werden?

The manufacture of PVC is necessary for supplying the demands of modern society, for maintaining the equilibrium in the chemical industry such as the manufacture of caustic soda solution-chlorine by means of rocksalt electrolysis, and for the safe disposal of chlorine for environmental reasons. The manufacture of vinyl chloride and dichloroethane is illustrated. The conventional processing of PVC into consumer goods, after treatment of rigid and plasticized PVC compounds or granulate, is demonstrated.

Influence of potassium fluoride on the syntheses of methylpiperazine-modified poly(vinyl chloride)s for use as fixed-site proton carrier membranes.

Aminated poly(vinyl chloride) (PVC) membranes were prepared that had a Nernstian response over a wide range of pH. The reaction between PVC and methyl-piperazine (MePIP) in dimethylformamide (DMF) was studied over a wide range of time and temperature, and in the presence of the catalyst, potassium fluoride (KF). Time, temperature, and KF increased the nitrogen (N) content of the resulting polymers, but sometimes at the expense of decreasing their specific viscosities (molecular weights). Activation energies of processes that occurred in different temperature ranges were estimated assuming an Arrhenius relationship. A Nernstian response occurred once the N content approached to about 0.3 w/w %, and was accelerated by the presence of KF at elevated temperatures. Increasing the N content above about 3% led to a loss of the Nernstian response either because of an increase in the double bond content and a subsequent decrease in polymer mobility, or because of a decrease in the molecular weight of the copolymer and concomitant difficulties in film preparation.

Vinyl chloride-induced hepatic coproporphyrinuria with transition to chronic hepatic porphyria.

A chronic hepatic disorder of porphyrin metabolism was found in 36 workers with vinyl chloride (VC)-induced hepatic injury following long-time industrial exposure. Pathologic porphyrinuria, especially secondary coproporphyrinuria with transition to subclinical chronic hepatic porphyria, is a consistent pathobiochemical parameter for the recognition of VC hepatic lesions. The porphyrinuria is of diagnostic value for the incipient toxic phase. Erythrocyte uroporphyrinogen decarboxylase activity studied in six cases with initial chronic hepatic porphyria was normal, suggesting that VC affects only this enzyme in the liver.