Polyvinyl Chloride Sheet Research Articles

Effect of gamma-ray irradiation on degradation of di(2-ethylhexyl)phthalate in polyvinyl chloride sheet

The risk assessment of di(2-ethylhexyl)phthalate (DEHP) migration from polyvinyl chloride (PVC) medical devices is an important issue for patients. The aim of this study was to determine DEHP degradation and migration from PVC sheets. To this end, the method for the simultaneous determination of DEHP and its breakdown products (mono(2-ethylhexyl)phthalate (MEHP) and phthalic acid (PA)) was improved. Their migration levels from 0 to 50 kGy gamma-ray irradiated PVC sheets were determined. DEHP migration level decreased in proportion to the dose of gamma-ray irradiation, while MEHP and PA migration levels increased. The hardness and the elastic modulus of PVC sheets were examined, but no clear relationship between DEHP migration and these parameters was observed.

Surface Modification of Polyvinyl Chloride Sheets via Growth of Hydrophilic Polymer Brushes

Poly(N,N-dimethylacrylamide) (PDMA) brushes were successfully grown from polyvinyl chloride (uPVC) sheets via well-controlled surface-initiated atom transfer radical polymerization (SI−ATRP). An ATRP initiator containing a chloropropionate moiety was chemically tethered onto the surface of PVC via a novel wet chemical modification. Negatively charged sulfate groups were introduced to facilitate polymerization. By incorporating a chemically cleavable group into the initiator, molecular weight, polydispersity and graft density of a series of PDMA brushes synthesized on the flat surface were unambiguously characterized for the first time by gel permeation chromatography. ATR−FTIR, contact angle, SEM and AFM were used to characterize the PDMA grafted surfaces. Reaction conditions such as monomer concentration, reaction time, copper(II) concentration and salt additives were varied to systematically investigate their effects on molecular weight and graft density of the PDMA grafted from PVC. Molecular weights o...

Effectiveness of Newly-Designed Electric Fences in Reducing Crop Damage by Medium and Large Mammals

Abstract. Many mammal species can cause crop damage simultaneously at one location; therefore, we designed and tested three fence types that targeted medium and large mammals. Ten mammal species were targeted (Japanese hare, raccoon dog, red fox, Japanese marten, masked palm civet, Eurasian badger, Asiatic black bear, wild boar, sika deer, and Japanese macaque). All three fences were electric and an expanded metal lath carried the current. To prevent invasions through lower gaps, the gap between the expanded metal lath and the ground surface was closed using a corrugated polyvinyl chloride sheet as an insulating material. After the fences were constructed, infrared-triggered cameras were set up both inside and outside the fences. All three fences prevented invasion by the targeted species. Overall, these fences had high practical value for nine of the targeted species; the exception was the Asiatic black bear, which was observed only once.

Effects of welding procedures on mechanical and morphological properties of hot gas butt welded PE, PP, and PVC sheets

AbstractMechanical and morphological properties of hot gas butt welds on polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC) sheets for four different procedures, which are single and double V‐welds with and without a welding shoe, were investigated. Besides, weldabilities of base materials were evaluated by rheological measurements. These revealed that weldabilities of PE and PP sheets were better than that of PVC. Welding energy (Ew), which is transferred onto weld surfaces, was calculated to evaluate weld quality. The results of tensile, impact, and bending tests indicated that the weld strengths of PVC sheets were lower than those of PE and PP sheets. When the welding shoe was used, weld strength increased significantly for each material because of the presence of sufficient welding pressure and the effective heating on surfaces. The best results were attained for the double V‐welds with the welding shoe. Morphology of welded regions was evaluated by polarized light, stereo, and scanning electron microscopy. Polarized light microscopy studies indicated that the heat‐affected zone (HAZ) consisted of welding rod core, molten zone, and deformed spherulitic zone, and the welding interface was indistinguishable from the base material when the welding pressure was enough. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

Activation of polyvinyl chloride sheet surface for covalent immobilization of oxalate oxidase and its evaluation as inert support in urinary oxalate determination

Polyvinyl chloride (PVC) sheets are a promising material for enzyme immobilization owing to the PVC’s properties such as being chemically inert, corrosion free, weather resistant, tough, lightweight, and maintenance free and having a high strength-to-weight ratio. In this study, this attractive material surface was chemically modified and exploited for covalent immobilization of oxalate oxidase using glutaraldehyde as a coupling agent. The enzyme was immobilized on activated PVC surface with a conjugation yield of 360 μg/cm 2. The scanning electron micrographs showed the microstructures on the PVC sheet surface revealing the successful immobilization of oxalate oxidase. A colorimetric method was adopted in evaluating enzymatic activity of immobilized and native oxalate oxidase. The immobilized enzyme retained 65% of specific activity of free enzyme. Slight changes were observed in the optimal pH, incubation temperature, and time for maximum activity of immobilized oxalate oxidase. PVC support showed no interference when immobilized oxalate oxidase was used for estimation of oxalic acid concentration in urine samples and showed a correlation of 0.998 with the values estimated with a commercially available Sigma kit. The overall results strengthen our view that PVC sheet can be used as a solid support for immobilization of enzymes and in the field of clinical diagnostics, environmental monitoring and remediation.

Diode Laser Cure of Serigraphic Ink

Laser polymerization of serigraphic ink was performed by diode laser (DL). Experimental tests were carried out by depositing a commercial solvent-based ink on a polyvinylchloride (PVC) sheet. Ink cure was obtained using a 940 nm emission wavelength DL with an almost rectangular spot. We considered different values for laser power, scanning rate and focalization distance and several behaviors were observed depending on the laser fluence, from the uncured ink state to substrate warpage and degradation. Both ink thickness measurement and scratch tests were conducted on laser-processed samples. Analysis of experimental results shows that the full cure can occur within an extremely short time and at very low power values.

Simultaneous Determination of Di(2‐ethylhexyl)phthalate, Mono(2‐ethylhexyl)phthalate, and Phthalic Acid Migrating from Gamma‐Ray Irradiated Polyvinyl Chloride Sheet by Liquid Chromatography‐Tandem Mass Spectrometry

The aim of the present study was to establish a liquid chromatography‐tandem mass spectrometric (LC‐MS/MS) method for the simultaneous determination of di(2‐ethylhexyl) phthalate (DEHP), mono(2‐ethylhexyl)phthalate (MEHP), and phthalic acid (PA). In the proposed method, the limits of detection of DEHP, MEHP, and PA were 5, 0.5, and 1 ng/mL, respectively, and the limits of quantification with standard solutions were 20, 2, and 5 ng/mL, respectively. Intra‐ and interday assays showed good accuracy and repeatability. The recoveries of DEHP, MEHP, and PA from respective extraction solvents ranged from 98.9 to 104.2% (relative standard deviation was below 10.3%). DEHP and its breakdown products migrating from gamma‐ray irradiated polyvinyl chloride (PVC) sheets were determined simultaneously since DEHP is easily eluted from PVC medical devices. DEHP migration was noted from both gamma‐ray irradiated and control PVC sheets. Compared with the migration from the control PVC sheet, MEHP showed significant migration from the gamma‐ray irradiated PVC sheet. In contrast, PA migration was noted only from the gamma‐ray irradiated PVC sheet.

X‐ray pole figures to assess orientation in PVC sheets

AbstractA series of X‐ray pole figures were obtained from oriented and unoriented rigid polyvinyl chloride sheets. From these, information about crystallite orientation in uniaxially and biaxially drawn sheets stretched at 90°C was obtained. Uniaxial orientation produced two crystallite orientations with the extent of orientation increasing with draw ratio; for biaxial samples the chain direction (c) was distributed uniformly in the plane of the sheet, with the planar orientation improving as draw ratio increased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 528–535, 2007

Study of rolling by corrugated rollers

A universal setup was developed and patented to produce polymer sheets corrugated by rolling. To calculate the basic process variables of the process of rolling by the setup, a method is proposed to consider the effect of the geometrical and kinematical parameters on the magnitude of the separating force being needed to roll the polymer with allowance for its rheological properties. Some features of the rolling process by corrugated rollers are studied. The viscous-flow and elastic properties of melts of various compositions of polyvinylchloride and low-density polyethylene are studied, the melt flow curves are constructed, and the melt swelling factors are determined. In a feed stock, the permissible moisture content is determined. The tensile strength of corrugated polyvinylchloride sheets is measured. With an increase in the density of the corrugated sheet material, the water absorption is demonstrated to decrease.

Novel Hybrid Filter for the Treatment of Septic Tank Effluent

Intermittent sand filtration is a common and effective method for treating septic tank effluent. However, if the loading rate is too high, clogging and ponding of the sand filter surface layer can occur due to the accumulation of excessive biomass and the deposition of suspended solids. This ponding limits the practicality of sand filtration as it makes it necessary to take the filter out of service for maintenance. The objective of this study was to develop and test, on-site, a new hybrid filter system that would reduce the risk of clogging at an organic loading rate substantially greater than the maximum recommended loading rate for intermittent sand filters. The system comprised a 0.6 m deep horizontal flow biofilm reactor (HFBR) over a 0.85 m deep stratified sand filter. The HFBR consisted of a stack of 20 horizontal corrugated polyvinyl chloride sheets, at 32 mm vertical spacings. The sheets were arranged so that the wastewater flowed over and back along alternate sheets down through the stack. The m...

Effect of sterilization process on the formation of mono(2-ethylhexyl)phthalate from di(2-ethylhexyl)phthalate

The risk assessment of di(2-ethylhexyl)phthalate (DEHP) migrating from polyvinyl chloride (PVC) medical devices is an important issue. Many studies have been conducted to determine the level of DEHP migration. A recent report has indicated that DEHP in blood bags is hydrolyzed by esterase into mono(2-ethylhexyl)phthalate (MEHP). However, MEHP is thought to be even more toxic than the parent compound. Therefore, a method for the simultaneous determination of DEHP and MEHP was developed. The limits of quantification (LOQs) of DEHP and MEHP were 2.5 and 0.75 ng/ml, respectively. In this study, the effect of sterilization process on the levels of DEHP and MEHP migration was investigated. The level of migration of DEHP from gamma(γ)-ray sterilized PVC sheet was low compared with that of the unsterilized control. By contrast, the level of MEHP migration from the γ-ray sterilized PVC sheet was high compared with that of the unsterilized control. In addition, a high content of MEHP was found in the γ-ray sterilized PVC sheet.

Particle-scale surface interactions of non-dilative interface systems

Millimeter and micron length scale particle–surface interactions are of fundamental importance in the modeling and actual field behavior of geotechnical composites incorporating non-dilative interface systems. The results of a basic experimental study to explain underlying causes of steady state strength behavior of these systems are presented. Single soda lime glass beads and natural subrounded quartz sand were placed in unlubricated sliding against manufactured materials consisting of high-density polyethylene, polyvinylchloride, fiber reinforced plastic, stainless steel and heat-treated steel. For high-density polyethylene and polyvinylchloride sheet materials steady state is reached after the rate of wear diminishes. In contrast, fiber reinforced plastic and steels exhibit a higher friction coefficient at large displacement than at peak due to interactions of the particle with the surface at the grain level. Initial peak and steady state friction coefficients depend primarily on the initial surface microtopography, grain shape, relative hardness of the particle and material pairing, normal stress and manufactured material morphology. The results give engineers an improved framework for assessing laboratory results and potential influence of wear on mechanical and hydraulic properties of construction materials.

Interactive computer software development for leaf area measurement

A novel idea of utilizing only a computer to determine leaf area and perimeter was developed. The procedure is essentially computer software developed in Visual Basic that uses the computer monitor as the working surface to trace leaf outline and determines leaf area, perimeter, length, and width. Testing the software for effects of orientation, shape, and size of objects was carried out using opaque (paper) and transparent (polyvinyl chloride sheet) geometrical planar objects of known properties, such as regular polygons (three to eight sides), rectangles, and circles, developed by AutoCAD precision drawings. Direct leaf samples of mango, guava, egg plant, and castor representing varied shapes and sizes were used in measurements and results were also compared with existing graphical and digital planimetric methods. Component methods used in determination were area under the curve (AUC) and pixel count (PC), which was further divided into pixel count-inside (PCI) and pixel count-total (PCT). In general, geometrical objects area and perimeter measurements were found to be independent of orientation, shape, and size. However, perimeters of squares and rectangles obtained by PC methods were affected by object orientation. As the traced transparent samples do not offer appreciable improvement in estimations, opaque samples are recommended because they are convenient and directly used in measurements. Based on the performance with geometrical objects, the software was considered to handle objects of any shape and size equally well. Measurements with direct leaf samples compared well with the graphical (−4.62% to 7.81% deviation) and digital planimetric (−4.05% to 8.48% deviation) results, and variation was found to exist even among these basic methods possibly due to unavoidable manual tracing errors. Based on this study, PCI method for area and AUC method for perimeter determination are recommended. The developed software proved to be an accurate method for measurements of area and perimeter of leaves and other planar objects, such as maps; extends the application of personal computers to such measurements; and was less expensive as it does not require additional hardware.

Reducing the migration of di-2-ethylhexyl phthalate from polyvinyl chloride medical devices

We attempted to determine the processing conditions for decreasing the migration of phthalate esters, particularly di-2-ethylhexyl phthalate (DEHP), from polyvinyl chloride (PVC) products using a drug solvent after dilution based on the package insert. PVC sheets and PVC tubing were subjected to optical irradiation (ultraviolet (UV), visible light irradiation) and heat treatment to determine whether they are deteriorated by these treatments. UV irradiation to one side of the PVC sheet decreased the levels of DEHP migration from the sheets by almost 50%, although the amount of DEHP content in PVC sheet was observed no significant change. On the other hand, the levels of DEHP migrating from the inner surface of PVC tubing UV-irradiated from the outer surface were not decreased compared with the control. Therefore, the surface structure was examined by conducting Fourier transform infrared spectroscopy (FT-IR), electron spectroscopy for chemical analysis (ESCA) and static angle of contact measurement. In FT-IR analysis, we found that the UV-irradiated PVC sheets were exhibited broadened absorption bands with time. In ESCA analysis, the chlorine content was decreased and the oxygen content was increased with time in UV-irradiated PVC sheets. Moreover, the other treated PVC sheets shows no significant change compared with the non-UV-irradiated PVC sheet. Therefore, the surface structure of the UV-irradiated PVC sheet was changed. As a result, the migration of DEHP from PVC products can be decreased with simple treatment, such as UV-irradiation. This could be a useful method to develop novel PVC products.

Development of a simple method for predicting the levels of di(2-ethylhexyl) phthalate migrated from PVC medical devices into pharmaceutical solutions

This study deals with the development of a simple method for predicting the elution levels of di-2-ethylhexyl phthalate (DEHP) from medical devices made of polyvinyl chloride (PVC) by using the physicochemical properties of pharmaceutical injections as a marker. GC-MS analysis showed that the release of DEHP from medical grade PVC product was concentration-dependently increased by extraction with two kinds of lipophilic injections (Sandimmun® and Prograf®) and three kinds of surfactants (HCO-60, Tween® 80, and SDS). The solubility of lipophilic pigments such as Sudan III, methyl yellow, and 1,4-diamino-anthraquinone against these solutions were also increased in a concentration-dependent manner, in which methyl yellow showed the highest response regarding the increase of optical density (O.D.). Further, electrical conductivity and static contact angle to the PVC sheet of the solutions were also increased or decreased in the same manner. As a result of the comparative study, significant correlation was found between DEHP release levels and these three physicochemical properties, particularly methyl yellow solubility, of the solutions tested. To evaluate the relationship in detail, DEHP release levels from PVC tubing and methyl yellow solubility of 53 injections used in gynecologic and obstetric fields were determined. None of the hydrophilic medicines showed any significant release of DEHP, and all showed low solubility of methyl yellow. On the other hand, the lipophilic medicines releasing a large amount of DEHP showed high solubility of methyl yellow (greater than O.D. 0.8). These results indicate that a significant proportional relationship exists between DEHP release potency and methyl yellow solubility of pharmaceutical solutions, and the risk of DEHP exposure to the patients administered pharmaceuticals through transfusion set could be easily predicted by the solubility test without complicated elution tests of DEHP using GC-MS or LC-MS.

Microbial treatment of bis (2-ethylhexyl) phthalate in polyvinyl chloride with isolated bacteria

In this study, we investigated the use of microbes to degrade and remove bis (2-ethylhexyl) phthalate (DEHP), a common plasticizer and a suspected endocrine disruptor, exuding from polyvinyl chloride. Four species of bacteria that utilize DEHP as their sole carbon source were isolated from garden soil, one of which, strain NK0301, was markedly more efficient than the others in degrading DEHP and was chosen for further studies. Strain NK0301 was a coryneform bacterium (1.5x1.0 microm) identified as Mycobacterium sp. from its 16S rDNA sequencing homology. It readily degraded DEHP to two major products determined by gas chromatography/mass spectrometry to be 2-ethylhexanol and 1,2-benzenedicarboxylic acid. Other phthalate esters, suspected of being endocrine disruptors, were also tested and all except two could be utilized by strain NK0301 as their sole source of carbon. When strain NK0301 was cultivated on polyvinyl chloride sheets containing DEHP as the plasticizer, it removed up to 90% of DEHP in 3 d. Following this treatment, the polyvinyl chloride sheets did not exude DEHP to artificial saliva.

しゅんぎくからのクレゾールリン酸エステル検出原因の解明

Unknown peaks were detected in the chromatogram of garland chrysanthemum extract in analysis of organophosphorus pesticide residues. The unknown peaks were identified as isomers of tricresyl phosphate (TCP) by GC/MS. TCP is used as a plasticizer in polyvinyl chloride, and there is no report of its detection in foods. Therefore, we investigated the origin of TCP detected in garland chrysanthemum. We found no effect of contact with packaging film or polyvinyl chloride sheet used in greenhouses. However, TCP was detected at 0.03 microg/g (average) in 16 of 20 samples of garland chrysanthemum that had been in contact with polyvinyl chloride tubing used for warming greenhouses. These results indicate that TCP migrated to the garland chrysanthemum from the tubing used to keep greenhouses warm.

コンクリート床下地の施工労力と床の品質および保全労力に関する実験的研究

The purpose of this study is to investigate effect of execution effort of concrete ground work to the quality of floor surface and the maintenance work of floor. Four specimens of concrete ground work constructed in the different execution conditions are provided for the exoeriment. For each specimens measured flatness of floor surface, finished by polyvinyl chloride sheet, is compared with the time spent for execution of concrete ground work and maintenance of floor. The result shows that the more effort of concrete ground work spent, the higher quality of floor surface realized, and the less work of maintenance needed.

Hydrophilization of PVC surfaces by argon plasma immersion ion implantation

Commercial polyvinylchloride (PVC) sheets were treated by plasma immersion ion implantation, PIII. Samples were immersed in argon glow discharges and biased with 25 kV negative pulses. Exposure time to the bombardment plasma changed from 900 to 10,800 s. Through contact angle measurements, the effect of the exposure time on the PVC wettability was investigated. Independent of t, all samples presented contact angles, θ, equal to zero after the treatment. However, in some cases, surface hydrophilization was not stable, as revealed by the temporal evolution of θ. Samples bombarded for shorter periods recovered partially or totally the hydrophobic character while the one exposed for the longest time stayed highly hydrophilic. These modifications are ascribed to the Cl loss and O incorporation as shown by XPS measurements. Furthermore, the mobility of surface polar groups and the variation in the cross-linking degree can also affect the PVC wettability.

遮水シートの変形強度特性に関する実験的考察―引張り強度の温度特性および応力緩和特性の評価―

Laboratory examinations and numerical analyses were undertaken to clarify the deformation and strength behaviors of water proof sheet, applied at a seepage control structure in an offshore waste disposal site. Water proof sheet, used in this study, is made of Polyvinyl Chloride (PVC), which is mainly used in an offshore waste disposal site. Tensile strength measured on several temperature conditions decreased linearly with the increase of temperature. Degree of stress relaxation of PVC sheet was shown to be constant irrespective of the magnitude of strain, and we proposed the equation about stress relaxation behavior by five-element viscoelastic model. Relationship between tensile stress and strain was evaluated on different strain rate conditions. As the result, tensile stress became larger with the increase of strain rate in the range of small strain, however, in the range of large strain, gradients of stress-strain curves became same for all strain rate conditions.Creep behavior and the puncture strength using backfilling stone are now under examination, and we will construct a comprehensive model, including those time-dependent deformation and strength properties of PVC sheet.