Polyvinyl Chlorides Research Articles

Work‐related skin disease in the plastics industry

In a survey of a representative sample of workers taken at each of four different plastics manufacturers, 122 completed self-administered questionnaires were obtained. Twenty-six respondents (21.3%) met the case definition for having a work-related skin disorder during the preceding year. Sixteen (61.5%) cases indicated that their skin problems were present for 11 or more days, and 50% reported that their normal daily activities were at least somewhat affected. Risk of disease was elevated for workers who reported skin contact with formaldehyde (OR = 3.30; 95% CI = 1.02–10.69) or with polyvinylchlorides (PVCs) or their prescursors (OR = 4.08; CI = 1.19–14.06), used barrier creams (OR = 4.51; CI = 1.22–16.68), were female (OR = 5.42; CI = 0.97–30.22), were 35 or younger (OR = 4.65; CI = 1.53–14.19), and for each use of hand cleaner at work (OR = 1.22; CI = 1.05–1.41). These findings should be considered when designing programs to reduce the incidence of skin disease among workers in the plastics industry. Am. J. Ind. Med. 31:545–550, 1997. © 1997 Wiley-Liss, Inc.

Work-related skin disease in the plastics industry.

In a survey of a representative sample of workers taken at each of four different plastics manufacturers, 122 completed self-administered questionnaires were obtained. Twenty-six respondents (21.3%) met the case definition for having a work-related skin disorder during the preceding year. Sixteen (61.5%) cases indicated that their skin problems were present for 11 or more days, and 50% reported that their normal daily activities were at least somewhat affected. Risk of disease was elevated for workers who reported skin contact with formaldehyde (OR = 3.30; 95% CI = 1.02-10.69) or with polyvinyl-chlorides (PVCs) or their precursors (OR = 4.08; CI = 1.19-14.06), used barrier creams (OR = 4.51; CI = 1.22-16.68), were female (OR = 5.42; CI = 0.97-30.22), were 35 or younger (OR = 4.65; CI = 1.53-14.19), and for each use of hand cleaner at work (OR = 1.22; CI = 1.05-1.41). These findings should be considered when designing programs to reduce the incidence of skin disease among workers in the plastics industry.

Calcium stearate in resins and resinous polymers: part 2

The second in a two‐part series, describes various applications of calcium stearate in resins and resinous polymers. Focuses in particular on its use in polypropylenes and stynenes (e.g. as a slip agent, a dispersing agent, a light stabilizer, or a nucleating agent) and in polyvinyl chlorides (e.g. as a pure‐proofing agent, to enhance ageing and heat resistance or as a non‐toxic stabilizer against acid, heat and light). Also considers the different applications of various stearate blends.

Hydrogen evolution on metallized plastic packed bed electrodes

This paper describe the electrolytic production of hydrogen using packed bed electrodes of metallized plastic. Particles or screens of polyvinyl chlorides (PVC) were metallized by chemically deposited copper or silver and used to fabricate packed bed electrodes. These electrodes were used for the electrolysis of flowing alkaline solutions under different conditions of electrolyte concentration and temperature. The matrix resistivity of the packed bed electrodes was found to influence their polarization behaviour. This resistivity decreased by further electroplating of the packed bed with Ag, Ni or Pd. The effects of these electrocatalytic materials on the polarization of the hydrogen evolution reaction were evaluated and analysed. The electrocatalytic activity of the electrodes used in this study was in the order: Pd/Cu/PVC≅Ni/Cu/PVC > Ag/Cu/PVC > Cu/PVC. These electrodes showed excellent metallic conductivity with good chemical and mechanical stabilities.

Strength of modified polyvinyl chloride films taking account of operating conditions

Experimental data are given for the strength and deformability of a wide range of polyvinyl chloride films obtained by combining different grades of polyvinyl chlorides and modifiers. The effect is considered of temperature and longterm climatic factors on the strength of these materials. The possibility is demonstrated of predicting the change in deformability of polyvinyl chloride films under conditions of natural solar radiation on the basis of results of rapid tests under the action of ultraviolet light.

A summary of the NBS literature reviews on the chemical nature and toxicity of the pyrolysis and combustion products from seven plastics: Acrylonitrile–butadiene–styrenes (ABS), nylons, polyesters, polyethylenes, polystyrenes, poly(vinyl chlorides) and rigid polyurethane foams

AbstractA series of literature reviews was undertaken by the National Bureau of Standards to examine the toxicity and chemistry of the effluents produced when seven plastics were decomposed under various thermal and atmospheric condition. These plastics are: acrylonitrile–butadiene–styrenes, nylons, polyesters, polyethylenes, polystyrenes, poly(vinyl chlorides) and rigid polyurethane foams. The English‐language literature on each of these was reviewed and published as a separate report of the National Bureau of Standards. Over 400 different thermal decomposition products, many common to more than one plastic, were identified. The toxicity of most of these individual products is products, many common to more than one plastic, were identified. The toxicity of most of these individual products is unknown and an assessment of the toxicity of the multitude of possible combinations is not feasible at this time. Therefore a variety of bioassay toxicity protocols have been used to assess the toxicity of the gaseous atmospheres generated by the thermal decomposition of these plastics. In general, these seven plastics did not produce unusually or extremely toxic pyrolysis or combustion products when compared with those of other synthetic or natural materials. In a few cases involving additives, toxic products of concern were produced.

Toxicity of the pyrolysis and combustion products of poly(vinyl chlorides): A literature assessment

AbstractPoly(vinyl chlorides) (PVC) constitute a major class of synthetic plastics, Many surveys of the voluminous literature have been performed. This report reviews the literature published in English from 1969 through 1984 and endeavors to be more interpretive than comprehensive. PVC compounds, in general, are among the more fire resistant common organic polymers, natural or synthetic. The major products of thermal decomposition include hydrogen chloride, benzene and unsaturated hydrocarbons. In the presence of oxygen, carbon monoxide, carbon dioxide and water are included among the common combustion products. The main toxic products from PVC fires are hydrogen chloride (a sensory and pulmonary irritant) and carbon monoxide (an asphyxiant). The LC50 value calculated for a series of natural and synthetic materials thermally decomposed according to the NBS toxicity test method ranged from 0.045 to 57 mg l−1 in the flaming mode and from 0.045 to > 40 mg l−1 in the non‐flaming mode. The LC50 results for a PVC resin decomposed under the same conditions were 17 mg l−1 in the flaming mode and 20 mg l−1 in the non‐flaming mode. These results indicate that PVC decomposition products are not extremely toxic when compared with those from other common building materials. When the combustion toxicity (based on their HCI content) of PVC materials in compared with pure HCI experiments, it appears that much of the post‐exposure toxicity can be explained by the HCI that is generated.

Permeation of protective clothing materials by methylene chloride and perchloroethylene.

The permeation of methylene chloride and perchloroethylene through seven protective clothing materials was studied to determine the permeation parameters, and to investigate the effect of solubility (polymer weight gain) and material thickness on the permeation parameters. The materials tested were two different nitrile rubbers, neoprene, Combination (a blend of natural rubber, neoprene and nitrile), two different polyvinyl chlorides, and polyvinyl alcohol. Methylene chloride permeated through all materials, except PVA, with breakthrough times in the range of 2 to 8 min, and permeation rates in the range of 1250-5800 micrograms/cm2 X min. PVA and unsupported nitrile offered good protection against perchloroethylene with breakthrough time occurring after 2 hr. Perchloroethylene permeated through the other materials with breakthrough times in the range of 8 to 36 min and permeation rates in the range of 200 to 1600 micrograms/cm2 X min. It was shown that for both chemicals, there is a correlation between the solubility (weight gain) and the ratio of permeation rate to breakthrough time (PR/BT). For all material/chemical pairs, an increase in solubility, increased (PR/BT). The change in material thickness had an effect on breakthrough time and permeation rate, but no effect on normalized breakthrough time. An increase in thickness reduced permeation rate and increased breakthrough time.

High-Field1H-NMR Study of Poly(Vinyl Chloride) Defects

Abstract Radical poly(vinyl chlorides), (PVC), obtained in bulk and in suspension polymerizations, and their low molecular weight extracts have been thoroughly studied by high-field NMR to obtain better qualitative and quantitative analyses of their structural defects. Assignments have been achieved by 1H-1H decoupling experiments and hyperfine spectral structure analysis of model compounds and low molecular weight extracts. Strong effects of the nature of the solvents used in 1H-NMR analysis were observed. Most of the defects of these radical PVC's have been quantitatively estimated in terms of average number values in correlation with their [Mbar]n. End-groups of type [I'] (= −CH2−CH[dbnd]CH[sbnd]CH2C1) are about 0.5 per chain; internal double bonds can only be estimated by difference, and their amount increases with increasing conversion. A very low quantity of vinyl chain end [I'] ([dbnd] [sbnd]CHC1[sbnd]CH[dbnd]CH2) has been found only in low molecular weight extracts. For the three probable saturated chloromethyl ends [II] ([dbnd][sbnd]CHCl[sbnd]CH2Cl), [III] ([dbnd] [sbnd]CH2[sbnd]CH2Cl), and [IV] ([dbnd] >CH[sbnd]CH2C1), only [II] and [III] were definitely identified. Finally, in taking into account all the endgroups, it has been concluded that branches would be grafted throughout the process. On the average, 4 to 5 branches have been found per chain of high molecular weight PVC.

Efferts of stabilizer and fibers on fatigue crack growth of glass fiber reinforced polyvinyl chloride.

From the observation of the fatigue crack growth behaviors and fractographs, the short glass fiber reinforced polyvinyl chloride with Sn series stabilizer was seemed to be anisotropic little and ductile, and the fiber reinforced polyvinyl chloride with Pb series stabilizer to be anisotropic and brittle during stable crack growth, though the mechanical properties of two kinds of fiber reinforced polyvinyl chlorides were anisotropic. It was found that the configuration of fatigue fracture surface ralated to the constants m and C values in Paris' Law, and the fatigue crack growth behaviors were influenced by the adhesive property between fibers and matrix resin due to the stabilizer.

Miscibility in poly(vinyl chloride)/chlorinated poly(vinyl chloride) blends, and blends of different chlorinated poly(vinyl chlorides)

AbstractBlends of poly(vinyl chloride) with chlorinated poly(vinyl chloride) (PVC), and blends of different chlorinated poly(vinyl chlorides) (CPVC) provide an opportunity to examine systematically the effect that small changes in chemical structure have on polymer‐polymer miscibility. Phase diagrams of PVC/CPVC blends have been determined for CPVC's containing 62 to 38 percent chlorine. The characteristics of binary blends of CPVC's of different chlorine contents have also been examined using differential calorimetry (DSC) and transmission electron microscopy. Their mutual solubility has been found to be very sensitive to their differences in mole percent CCl2 groups and degree of chlorination. In metastable binary blends of CPVC's possessing single glass transition temperatures (Tg) the rate of phase separation, as followed by DSC, was found to be relatively slow at temperatures 45 to 65° above the Tg of the blend.

Malignant fibrous histiocytomas induced in rats by polymers.

Five polymeric materials (3 polyvinyl chlorides, 1 polyhydroxyethyl methacrylate, and 1 dimethyl polysiloxane) were implanted into subcutaneous (SC) tissues of rats. Subcutaneous tumors developed in all experimental groups. The incidences of the tumors differed however, although the experimental conditions were the same for all these materials. This result indicates that chemical characteristics of the materials may influence the incidence of SC tumors. From the histological and electron-microscopic findings many of these tumors were diagnosed as malignant fibrous histiocytomas.

Comparative studies on the resistance of materials to species of Coptotermes (Isoptera: Rhinotermitidae). I. The susceptibilities of various plastics to C. acinaciformis (Froggatt) from Australia and C. formosanus Shiraki from China

AbstractThe susceptibilities of 14 plastics formulations (four polyethylenes, one polypropylene, one polyester, two polyamides, one polyurethane and five poly(vinyl chlorides)) to attack by Coptotermes acinaciformis (Frogg.) and C. formosanus Shir. in the laboratory were broadly related to hardness and surface finish. Overall, C. acinaciformis inflicted more damage than C. formosanus, despite lower survival, but some formulations appeared more susceptible to C. formosanus than to C. acinaciformis.

Foreign-body tumorigenesis in rats by various kinds of plastics--induction of malignant fibrous histiocytomas.

Five kinds of plastics (3 polyvinyl chlorides, 1 polyhydroxyethyl metacrylate and 1 dimethyl polysiloxane) were implanted into subcutaneous tissues of Wistar rats of both sexes. Subcutaneous tumors developed in all experimental groups. The incidences of the tumors, however, differed from each other, although these materials were tested on the same experimental condition. This result indicates that chemical characters of the materials may influence the incidence of subcutaneous tumors. Histologically, most of these subcutaneous tumors were mesenchymal tumors with spindle cells arranged in a storiform pattern, with sheets of histiocyte-like cells or pleomorphic giant cells. Electron microscopy showed mixture of fibroblastic cells, histiocytic cells and undifferentiated cells in these tumors. From these histological and electron microscopical findings, many of the tumors were diagnosed as malignant fibrous histiocytomas.

AL TECH MIAMI

Abstract AL TECH MIAMI is both a hardenable stainless steel (AISI Type 420) and a tool steel for making molds for plastic. A major requirement for plastic mold steel is corrosion resistance. Certain plastics, such as poly-vinyl chlorides, are very corrosive and stored molds often rust from sweating water lines and/or humid environments. AL TECH MIAMI has good resistance to wear. It is melted and AOD refined to assure the mold-maker of cleanliness and freedom from internal imperfections. It provides exceptionally good polishability for lens-quality molds. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and machining. Filing Code: SS-435. Producer or source: AL Tech Specialty Steel Corporation.

In vitro effects of 10,10′-oxybisphenoxarsine on isolated rat liver mitochondria

10,10′-Oxybisphenoxarsine (OBPA), a trivalent, heterocyclic organoarsenical, is a potent, broad spectrum antimicrobial agent often incorporated into plasticized polyvinyl chlorides. Although highly toxic, the mechanism of OBPA toxicity is unknown. Since it is hepatotoxic, we investigated the in vitro effects of OBPA on rat liver mitochondria. Isolated mitochondria were incubated with 1 to 8 μ m OBPA and oxygen consumption was monitored polarographically. State 3 respiration of α-ketoglutarate, pyruvate, isocitrate, and succinate was rapidly inhibited. OBPA also uncoupled oxidative phosphorylation, although this was masked, at higher concentrations, by progressive respiratory inhibition. The electron transport chain appeared unaffected by OBPA, as measured by NADH oxidation, but several tricarboxcylic acid cycle dehydrogenases were inhibited. This inhibition was prevented and, in some cases, reversed by glutathione. It is likely that OBPA, like other trivalent organoarsenicals, exerts its toxic effects by reacting with vital mitochondrial sulfhydryl groups.

Cyclopentadienylation of allyl-chlorine enriched PVC and degradation thereof

Pendant cyclopentadienyl groups (Cp) have been introduced by treatment with Me2CpAl into poly(vinyl chlorides) the allyl chlorine contents of which was augmented by mild chemical dehydrochlorination [PVC(A)]. Heating the cyclopentadienylated products [PVC(A)-Cp] led to gels, most likely by Diels-Alder addition, because the networks could be broken by strong dieno-philes, e.g., maleic anhydride. The thermal stability of PVC(A)'s was improved upon Me2CpAl treatment due to the substitution of thermally unstable allylic chlorines by Cp groups. The thermooxidative stability of PVC(A)-Cp was reduced relative to that of PVC(A) on account of the high oxidizability of Cp groups in the resin.

Poly(vinyl chloride)–polyol (AB)x block copolymers: Synthesis, characterization, and mechanical properties

AbstractPoly(vinyl chloride)–polyol (AB)x block copolymers have been prepared by the condensation polymerization of low‐molecular‐weight hydroxy‐terminated poly(vinyl chlorides) (PVC) and diisocyanate‐capped polyester and polyether diols. The difunctional poly(vinyl chlorides) were synthesized by ozonization of commercial resin followed by metal hydride reduction. The (AB)x block copolymers, which contained 3000 or 4300 molecular weight PVC block sizes and 1000–2000 molecular weight polyol segments, had a wide range of mechanical properties, depending on overall polymer structure. Tensile strengths ranged from 7.8 to 31.5 MPa, elongations from 125% to 610% and torsional stiffness temperatures (Tf) from 25°C to −22°C.

Relationship between rheological properties and structure of poly(vinyl chloride)

Abstract The viscosity and extrudate swell as functions of shear rate and temperature as well as flow profiles and complex shear modulus were measured on the melt of three suspension poly(vinyl chlorides) of different molecular weights. For all the specimens the primary particles, about 1 μ in diameter, had been previously destroyed by suitable milling. Below a distinct critical temperature the samples show a rheological behavior similar to that of slightly crosslinked amorphous polymers. Above this critical temperature the rheological properties are comparable to those of melts of amorphous polymers. The unusual rheological behavior of poly(vinyl chloride) is explained by the assumption of a network structure formed by crystallites in the melt. Because of the gradual melting of the crystallites the network becomes ineffective above temperatures of about 200°C. This temperature increases with increasing molecular weight. The assumption of crystallites acting as crosslinks in the melt is experimentally confirmed by the reversibility of the measured rheological effects, the wide melting range determined by differential scanning calorimetry, and electron micrographs which show particles of about 0.02 μm in size.

Compatibility of PVC-chlorinated PVC mixtures

Abstract This study deals with the compatibility of a poly(vinyl chloride) mixed separately with two industrial chlorinated poly(vinyl chlorides), denoted PVC/C1 and PVC/C2 (chlorine contents of 65.2 and 67.5%, respectively). The technique of mixing, examined for different compositions, is the main parameter for the compatibility of the resins. The mixtures were prepared either with a Brabender plastograph, with a milling cylinder at 190°C (the mixture being fluid), or by sintering at a temperature between 180 and 200°C under pressure. We determined the complex components of the elasticity modulus as a function of temperature (from 50 to 170°C at a frequency of 110 Hz) for each mixture, using a Rheovibron viscoelastometer. The study of the structure of the mixtures, based on the variation of the tangent of the loss modulus, allows us to say that the compatibility of polymers depends on the chlorine contents in chlorinated PVC; thus, at 65.2% the chlorinated polymer seems to be compatible with PVC, but at ...