Rigid Poly Vinyl Chloride Research Articles

Effect of Rigid PVC Bailer Contact on Detection of Pesticides in Water Samples

AbstractA field experiment was conducted to examine the effect of short‐term (one minute) contact of pesticide‐laden water with a polyvinyl chloride (PVC) bailer on quantitative laboratory measurements of seven pesticide concentrations in distilled water samples subsequently decanted from the bailer. Pesticides were tested at two initial concentrations (low. based on current FPA maximum contaminant levels, or MCL: and high, based on a multiple of approximately lour times the MCL). Pesticide species included bromoxynil, diclofop‐m, dimethoate. MCPA, methyl parathion, propiconazole, and trifluralin. Dimethoate recoveries were poor for all treatments. For all other pesticides there was no systematic difference between pesticide concentrations measured before and after bailer contact. Effectiveness of bailer decontamination treatments consisting of distilled water rinse alone was related to water solubility (S) for each species. Distilled water samples decanted from a rigid PVC bailer following initial bailer contact with pesticide‐spiked water, and after the bailer had been cleaned with a single distilled water rinse, had measured pesticide concentrations of less than 2 percent of the pesticide concentration in the initial pesticide‐spiked water, regardless of S. A single distilled water rinse effectively removed all trace of contaminants having S> 500 mg/L. Multiple distilled water rinses, and multiple distilled water rinses followed by 15 bailings of a well, effectively removed all trace of contaminants having S> 50 mg/L. Below threshold S, cleaning effectiveness decreased as a power function of S.

Effect of Various Materials in Multilevel Samplers on Monitoring Commonly Occurring Agrichemicals in Ground Water

AbstractStudies have shown that materials, such us polytetra‐fluoroethylene (PTFE), rigid polyvinyl chloride (rigid PVC). flexible polyvinyl chloride (flexible PVC), stainless steel (SS). low‐density polyethylene (LDPE), and high‐density polyethylene (HDPE), have the potential to influence certain analyte concentrations in ground water samples. The effects of HDPE, LDPE, PTFE, rigid PVC, and SS on aqueous concentrations of nitrate‐N, atrazine, deethylatrazine (DEA), and deisopropylatrazine (DIA) were evaluated in a field study A laboratory study was conducted to evaluate sorption of atrazine DEA, DIA, cyanazine, alachlor, metolachlor, and butachlor to PTFE, HDPE, and SS materials. Butachlor is rarely use in the United States, but was included because of its expected high sorptivity. No significant differences between HDPE, LDPE, PTFE, rigid PVC, and SS were determined for any of the analytes tested in the field study. In the laboratory study, sorption of DIA to PTFE and SS was significant at 2.6 × 10−5 and 4.1 × 10−5μg/m2 respectively. Sorption of DIAA to HDPE was not significantly > 0 sorption of all other compounds to HDPE, PTFE, and SS were also not significantly >0. Results of the two studies indicate that for these analytes (relatively polar or ionized compounds), representative ground water samples are not dependent on the materials used for multilevel sampler construction. When considering these compounds, it appears that the least expensive materials (HDPE, rigid PVC, and LDPE) are good choices for the construction of ground water monitoring wells.

Assessment of degree of fusion of rigid PVC from inverse gas chromatographic measurements

AbstractInverse gas chromatography of alkanes has been used to assess the degree of fusion of rigid polyvinyl chloride (PVC) extrudates. The relative degree of fusion is provided by ratios of the retention volumes of the alkane probe molecules in the bulk of the PVC. This method is nonintrusive and can be used to measure degree of fusion quantitatively if a completely fused reference material can be provided. The present analysis involves evaluations of the contributions to the overall retention volume of the alkane probes, resulting from adsorption and from bulk diffusion. The diffusivity of the alkanes was clearly dependent on the processing history of the PVC extrudate. A direct variation was observed between the size of the diffusing molecules and their residence time as adsorbates on the polymer surface. © 1995 John Wiley & Sons, Inc.

Effect of Concentration on Sorption of Dissolved Organics by PVC, PTFE, and Stainless Steel Well Casings

AbstractThis report examines sorption of low ppb levels of organic solutions by polytetra‐ fluoroethylene (PTFE), rigid polyvinyl chloride (PVC), and stainless steel 304 and 316 well casings. Nineteen organics were selected, including several munitions and chlorinated solvents. Compounds were selected to offer a range of physical properties, such as solubility in water, octanol/water partition coefficient, and molecular structure. When these results were compared with the results from a similar study conducted at ppm levels, the rate and extent of sorption by PTFE and PVC were the same as seen previously for almost all analytes. There were no losses of any compounds associated with stainless steel. At these low levels (ppm and ppb), the rate of diffusion within the polymer (PVC and PTFE) is independent of concentration. Only with PTFE are the rates rapid enough to be of concern when monitoring for some contaminants in ground water. Tetrachloroethylene was the compound PTFE sorbed the most rapidly. The study showed that PVC well casings are suitable for monitoring low levels (ppm and ppb) of organics.

Role of structure in rigid PVC recoil

Polyvinyl chloride (PVC) rheology is greatly influenced by its low crystallinity content and its particulate morphology. The present paper will discuss the role of morphology in the flow behavior of rigid PVC in both constrained and unconstrained recoil. PVC has a partially fused structure and the fusion level can be monitored with surface electron micrographs of the fracture surface. When PVC is suddenly (step) elongated, the fusion level is greater than in the unstrained state and increases with time. The relaxation behavior is close to a power-law function with a Doi–Edwards type damping function. In constrained recoil (reversing double step elongations) the fusion level is still greater than in the unstrained state and Wagner’s irreversible model fits the data. In unconstrained recoil (step elongation followed by stress removal) it is shown that the fusion level almost returns to its initial state. In order to predict this unexpected change, we use a modified Wagner irreversible model with a structural parameter affecting the relaxation behavior.

Lubricant systems for rigid PVC applications

AbstractLubricants are used in extrusion processing of rigid polyvinyl chloride (PVC) compounds to control fusion and reduce shear heating. Without lubricants, conversion to the melt state results in excessive shear heating and degradation of the compound. The present work compares new lubricant systems containing complex esters with conventional systems based on ethylene bisstearamide (EBS) and paraffin. These new systems provide improved compound stability, weatherability, and physical properties. In addition, use of these systems results in lower compound viscosity compared with the conventional lubricant packages. The effects of other characteristics of these systems, such as the degree of esterification on compound properties, are also discussed.

Dynamic Study of Common Well Screen Materials

AbstractExperiments simulating the dynamics of compliance sampling via a monitoring well were performed to assess the effects of common well screen materials (rigid polyvinyl chloride, polytetrafluoroethylene, stainless steel 304. and stainless steel 316) on several metals and tri‐ chloroethylene (TCE) in ground water. This was achieved by using a continuous flow‐through chamber system capable of exposing monitoring well screens to ground water for periods ranging from 0.25 to 8 hours. The findings of this study are more representative than static laboratory experiments for assessing the potential effects well casing materials have on ground water samples. Under dynamic flow conditions stainless steel 304 and 316 screens were found to influence solution concentrations of Pb, Cd, Cr, Ni, and Fe, while ground water TCE concentrations were not affected by any of the materials tested.

Photoreactions of phthalic acid dialkyl esters: a flash photolysis study

Phthalic acid di(2-ethylhexyl) ester (DOP), phthalic acid di(2,4,5-trimethylheptyl) ester (DIDP), phthalic acid di( n-decyl) ester (DDP) and phthalic acid dimethyl ester (DMP) were irradiated in dilute solutions of 1,1,2-trichlorotrifluoroethane (TIE), acetonitrile and dichloromethane and in a polyvinyl chloride (PVC) matrix with 20 ns flashes of 266 nm light. Transient absorption spectra formed during the flash ranging from about 250 to 700 nm are attributed to excited triplet states. Emission spectra observed at wavelengths between 300 and 600 nm consist of a short-lived portion, corresponding to delayed fluorescence (mainly P-type in fluid solution and E-type in the rigid PVC matrix) originating from ‘unmodified’ triplets and a long-lived portion attributed to triplet biradicals. Triplets of phthalic acid esters are quite unreactive towards chlorinated aliphatic hydrocarbons and PVC ( k 2 ⩽ 10 3 1 mol −1 s −1). The resulting radicals exhibit optical absorption at λ < 420 nm. In PVC films, a polymer matrix effect was detected for the decay of triplet excited species. Over the investigated temperature range (229–400 K) the decay can be described according to Kohlrausch's law by ‘stretched exponentials’: ln([ T] t/ [ T] 0) = −α t β. Both the matrix response factor α and the dispersion factor β increase with increasing temperature. The functions α= f( T −1) and α= f( T −1) exhibit a significant discontinuity (kink) at the glass transition temperature T g ≈ 353 K.

The effect of physical aging on properties of rigid polyvinyl chloride

AbstractThis paper describes the effects of physical aging on properties of rigid PVC, such as tensile strength, tensile modulus, Izod impact, coefficient of thermal expansion, specific gravity, differential scanning calorimetry, and heat deflection temperature.

The recoil of rigid PVC

Polyvinyl chloride (PVC) is widely used in industry, but it is difficult to find any extensive discussion of theological relations that describe it. The present paper discusses the behaviour of rigid PVC in extensional deformations at various temperatures. In the tests, a step elongation was applied at an initial time, then after a delay the specimen was cut, permitting recoil. Both linear and nonlinear strain regimes were studied; the linear relaxation properties (relaxation function, storage modulus) were cross-checked with eccentric-disk measurements. In the non-linear strain regime a single-integral constitutive equation of the KBKZ Wagner type was used. Separability of time and strain effects was demonstrated in our tests and so a “damping function” could be found which was only a function of strain. Video recordings of recoil were made, and detailed predictions of the strain-time behaviour were checked against experiments.

A Method to Determine the Potential Toxicity of Smoke from Burning Polymers: III. Comparison of Synthetic Polymers to Douglas Fir Using the UPitt II Flaming Combustion/Toxicity of Smoke Apparatus

Mice were exposed for 30 minutes to smoke from burning poly mers under naming conditions using the UPitt II apparatus for evaluation of flaming combustion/toxicity of smoke. The burning conditions were selected to enable comparison to Douglas fir data previously presented. The principal toxi cant was found to be CO for polymethyl methacrylate and polycarbonate. How ever, other toxicants, HCN and HCl, contributed to the observed lethality of smoke from rigid polyurethane foam and polyvinyl chloride respectively. The LC50 smoke concentration (in mg/L obtained from the mass loss rate and airflow rate) (SCLC50 ), survivable exposure concentration (SEC) and cumula tive hazard (Σ h) were calculated for these synthetic polymers to permit compar isons between these polymers and Douglas fir. As found with Douglas fir, the Σh for exposure to smoke from a burning polymer varied with the burning con ditions. However, the smoke concentration over the range of burning conditions evaluated, was a good predictor of lethality for each polymer tested.

A Comparative Analysis of the Loss of Amiodarone from Small and Large Volume PVC and Non-PVC Infusion Systems

The time-course of the adsorption of amiodarone hydrochloride onto flexible polyvinyl chloride (PVC) infusion bags and administration sets has been studied under ambient conditions similar to the intensive and coronary care units at the Repatriation General Hospital--Daw Park. When admixtures containing 900-1000 mg amiodarone hydrochloride in 500 ml PVC infusion bags containing glucose 5% were assayed, a minimal (2.7%) loss of amiodarone was detected at 24 hours compared with glass infusion bottles. There was no loss apparent when 100 ml PVC infusion bags were used compared with 100 ml glass bottles. When PVC administration sets were attached to 500 ml glass infusion bottles, maximal adsorption losses of up to 4.9% were observed in the effluent within one hour of the commencement of the simulated infusion. In Australia, the current recommendations by the distributor of amiodarone, Reckitt & Colman Pharmaceuticals, advise that the administration of amiodarone should be via glass infusion bottles or rigid PVC plastic containers without plasticisers together with non-PVC administration lines. These results do not support this recommendation.

Polyvinyl chloride and its organotin stabilizers with special reference to packaging materials and commodities: A review

Polyvinyl Chloride (PVC) is a thermoplastic that has entered practically all areas of life as a cheap and versatile material. Since PVC also fulfils the high quality requirements placed on modern packaging materials, with respect to packaging techniques and consumer protection, it is being used to an increasing extent for packaging of food and beverages as well as pharmaceutical and cosmetic products. The various additives required for processing PVC into packaging materials and commodity articles, as well as improving its properties during usage (e.g. lubricants and stabilizers), are harmless with regard to human and ecotoxicological aspects. Their use is non-hazardous and is therefore permitted by authorities. In the group of thermo- and light stabilizers for PVC, mixtures of mono- and dialkyltin thioglycolates play a major role. In accordance with legislation, these are allowed to be used in rigid PVC. In addition to their excellent stabilizing effect, they are not hazardous to the health of consumers of products packed in rigid PVC. Similarly, no health hazards exist to personnel, working in PVC production and processing plants, from volatile components of organotin stabilizers provided that processing and environmental prerequisites of modern technology are observed. The disposal of household waste that contains used PVC materials — stabilized with mixtures of mono- and dialkyltin thioglycolates — does not cause additional difficulties.

Foam Processing with Rigid Polyvinylchloride

Abstract Rheological and processing studies have been performed on the extrusion of neat and expandable polyvinylchloride (PVC) compounds. Processing additives greatly change both rheological and physical properties. In the normal PVC processing temperature range, the neat compound exhibits very small values of power-law index, which increase with temperature. The usual usage level of dioctylphthalate (DOP), a plasticizer, and Acryloid K-125, a processing aid based on polymethylmethacrylate, increases the power-law index, whereas BTA, an impact modifier based on terpolymer of methylmethacrylate-butadiene-styrene, decreases it. DOP normally decreases viscosity and first normal stress difference. On the other hand, Acryloid K-125 and BTA increase them. Plotting first normal stress difference against shear stress, however, eliminates the effect of DOP and BTA level. Inclusion of a blowing agent increases the powerlaw index, and produces a substantial reduction in viscosity. At high shear rates, all the viscosity data of the expandable PVC compounds fall onto the single viscosity curve of the neat PVC compound. Two blowing agents, azodicarbonamide (ADCA) and sodium bicarbonate (SBC), yield similar reduction of the torque on a screw, but ADCA brings about much larger viscosity reduction than SBC. Further, ADCA shows more rapid bubble expansion rate on leaving the die exit and produces more uniform cells. On the other hand, SBC requires induction time for bubble expansion after leaving the die exit and gives a wider cell size distribution. Particularly in the foaming process with SBC, skin formation is considerably promoted by incorporating small quantities of DOP along with BTA, suggesting a strong potential for manufacturing rigid PVC structural foams with thicker skins by a single extrusion process.

Polyvinyl chloride and its organotin stabilizers with special reference to packaging materials and commodities: A review

AbstractPolyvinyl Chloride (PVC) is a thermoplastic that has entered practically all areas of life as a cheap and versatile material. Since PVC also fulfils the high quality requirements placed on modern packaging materials, with respect to packaging techniques and consumer protection, it is being used to an increasing extent for packaging of food and beverages as well as pharmaceutical and cosmetic products. The various additives required for processing PVC into packaging materials and commodity articles, as well as improving its properties during usage (e.g. lubricants and stabilizers), are harmless with regard to human and ecotoxicological aspects. Their use is non‐hazardous and is therefore permitted by authorities. In the group of thermo‐ and light stabilizers for PVC, mixtures of mono‐ and dialkyltin thioglycolates play a major role. In accordance with legislation, these are allowed to be used in rigid PVC. In addition to their excellent stabilizing effect, they are not hazardous to the health of consumers of products packed in rigid PVC.Similarly, no health hazards exist to personnel, working in PVC production and processing plants, from volatile components of organotin stabilizers provided that processing and environmental prerequisites of modern technology are observed. The disposal of household waste that contains used PVC materials — stabilized with mixtures of mono‐ and dialkyltin thioglycolates — does not cause additional difficulties.

N‐substituted maleimides as thermal stabilizers for rigid polyvinylchloride

AbstractN‐substituted maleimides have been investigated as thermal stabilizers for rigid polyvinylchloride (PVC) at 180°C in air by measuring the rate of dehydrochlorination and the extent of discoloration of the polymer. The results reveal the higher stabilizing efficiency of these products relative to basic lead carbonate, dibutyl tin maleate, and cadmium‐barium stearate stabilizers commonly used in industry. The induction period (Ts) increases as a function of the positive resonance effect of the substituents (+R). Moreover, the investigated stabilizers impart better color stability for the degraded samples as compared with the stearate stabilizer. The stabilizer efficiencies are attributed to their radical trapping potency which intervenes with the radical degradation process of PVC, while the good color stability is due to the ability of the stabilizer to interact with the conjugated double bonds formed on the PVC chains as a result of degradation. A mechanism illustrating the stabilizer's action is proposed.

Packaging materials as smoke barriers during fire

AbstractDuring fires in warehouses and shops, the fire smoke and fire‐extinguishing agents often cause great damage to both packaged and non‐packaged goods. Even products that are stored at a great distance from the fire are often contaminated by the smoke.The decision as to whether such products, after re‐packing, are still in perfect condition or not must often be made quickly and it can be especially difficult to judge foodstuffs in this respect. Depending on time aspects and ignorance of the protective functions of a packaging material, the wrong decisions are often made, which results in unnecessary rejections.Generally, it can be said that fire smoke immediately penetrates thin films of, for example, polyethylene (PE), polyvinyl chloride (PVC), uncoated cardboard and paper, as well as PE‐coated cardboard. Packaging materials such as rigid PVC rapidly degrade due to the chemical substances in fire smoke.Evaluation of the barrier properties of packaging materials against model fire smoke shows great differences in breakthrough times between laminates with three or more layers and packaging materials with only one or two layers.

ポリ塩化ビニル被覆鋼板の機械特性に及ぼす可塑剤の影響

Strain developing polyvinyl chloride (PVC) films containing Al flake powder during formation was analyzed by a finite element method. It was found that stress in the film was concentrated at the edge of the Al flake powder, and led to breakdown of the film. Strain in rigid films was less than in flexible films. In an effort to improve the formability of PVC films containing Al flake powder used to coat sheet steel, the composition of the plasticizer in PVC plastisol was examined. It was found that by using a secondary plasticizer and a reactive plasticizer in the PVC plastisol containing Al flake powder it was possible to obtain a rigid PVC film, and the tearing load and tensile breaking load of the film were improved, resulting in good formability in a variety of roll forming processes.

Processing aids for chlorinated polyvinyl chloride

AbstractComparative studies of melt processability showed that chlorinated polyvinyl chloride (CPVC) had low melt index and high Brabender melt temperature and torque, as compared with conventional rigid polyvinyl chloride (PVC). Of 3 processing aids at 10 percent concentration, triphenyl phosphate increased melt index 30‐fold, fusion rate 10‐fold, melt temperature 20°C, and torque 31 percent in CPVC. Two other processing aids, an acrylic and a styrene/acrylonitrile copolymer, were less effective. Improvements in PVC were less dramatic than in CPVC. Overall, use of processing aids made CPVC processability equal or even superior to conventional rigid PVC.

ESR study of a 2,6-diterbutyl hydroxytoluene analog incorporated into rigid PVC: Effects of the immersion in various aqueous media

Study by electron spin resonance (ESR) of N (3,5-diterbutyl-4 hydroxybenzyl) 4 amino 2,2,6,6-tetramethylpiperidinyl oxy: ‘BHT-amino TEMPO’, a paramagnetic analog of BHT, incorporated into the usual compound of rigid polyvinyl chloride (PVC) revealed that after contact of the labelled polymer with aqueous media (water, 3% acetic acid, 20% ethanol) the BHT-amino TEMPO migrated and that the structure of the polymer was altered after 10 days of immersion at 50°C. This modification was assigned to the penetration of the aqueous media into the PVC. The ESR spectrum of the modified polymer consisted of two superimposed signals, the first one corresponding to BHT-amino TEMPO highly immobilized in the plastic material and the second to the same molecule moving more freely in spaces probably occupied by the solvent. Estimates of BHT-amino TEMPO levels in the immersion media seemed to indicate that they were of the same order of magnitude as the losses of the freer markers in the PVC after 10 days of immersion at 50°C.