Polyvinyltoluene Research Articles

Measurement of the complex refractive index of polyvinyltoluene in the UV, visible, and near IR: Application to the size determination of PVT latices

The complex refractive index of polyvinyltoluene (PVT) was obtained from optical measurements performed on thin films of this material in the UV, visible, and near IR. The turbidity spectra of PVT hydrosols were calculated for particle diameters ranging from 10 to 2000 nm in the same spectral domain. The particle sizes of several synthesized PVT hydrosols were then deduced from a comparison between the calculated spectra and the experimental spectra; especially the method based on the localization of the different extrema of the spectra was proven to be useful and accurate in determining the particle size. Some conclusions concerning the use of ordinary spectrophotometers in turbidity measurements are emphasized here.

Effect of in vitro exposure to hydrogen sulfide on rabbit alveolar macrophages cultured on gas-permeable membranes

Rabbit alveolar macrophages (AM) were cultured on gas-permeable membranes (Petriperm dishes) and standard 25-cm 2 plastic tissue-culture flasks (Falcon Plastics) and exposed to H 2S (50–60 ppm). Exposure of AM to approximately 54 ppm of H 2S for 24 hr during culture on gas-permeable membranes reduced the percentage of AM that phagocytized 2.02-μm polyvinyl toluene beads to 5% of control values. In contrast, AM cultured on plastic tissue-culture flasks showed no decrease in phagocytic ability when exposed to similar concentrations of H 2S. Unexposed AM were equally phagocytic under both culture systems. A decrease in phagocytic capability was most pronounced under continuous exposure regimens. Above a critical combination of H 2S concentration and duration of exposure, cessation of exposure did not halt a time-dependent degradation of phagocytic ability. Scanning electron microscopy of cultured AM exposed for 24 hr to 54 ppm H 2S revealed a general decrease in cell-surface ruffling and a pronounced loss of pseudopodia. Transmission electron microscopy of AM cultures exposed to 54 ppm H 2S for 24 hr revealed extensive disruption of interior organelles, cytoplasmic membrane degradation, and sharply reduced cell-surface ruffling.

An experimental test of a large‐volume plastic detector for use in aerial gamma‐ray spectroscopy

A large‐volume plastic detector for use in aerial gamma‐ray spectroscopy has been evaluated by the U. S. Geological Survey. The purpose of the evaluation was to compare the plastic polyvinyl toluene (PVT) detector with thallium‐activated sodium iodide [NaI(T1)] detectors in ability to define the surface distribution of gamma radiation from the decay of natural thorium, uranium, and potassium. Good performance from PVT detectors will allow aerial gamma‐ray detection to be less expensive and much less susceptible to physical or thermal shock compared to the use of NaI(T1) detectors. The experimental results indicate that PVT detectors can be used to measure the surface distribution of potassium (K), equivalent uranium (eU), and equivalent thorium (eTh). However, because of the relatively low‐energy resolution of the PVT detector and the subsequent increased interference among the energy windows used to measure K, eU, and eTh, the results of data reduction are statistically less accurate than those obtained using NaI(T1).

Radiation-chemical changes in polystyrene and its methyl derivatives

The radiation-chemical processes taking place during photolysis and radiolysis of polystyrene, polyvinyl toluene and poly-α-methylstyrene at 77–373°K, without additives and in the presence of low-molecular compounds, at dosages in the range of 1–1000 Mrad, in the condensed state and in solution, have been studied by ESR-, IR- and UV-spectroscopy and by various physicochemical methods. It is shown that in PS intermolecular bonds are formed by γ-radiation as a result of recombination of phenyl radicals and addition radicals, and in polyvinyltoluene, by recombination of phenyl and benzyl radicals. The presence of CH 3 groups in the benzene ring increases the efficiency of radiation crosslinking and protects the main chain of the polymer from degradation. The substitution of a methyl group for hydrogen on the α-carbon atom of the PS main chain weakens the C αC β bond considerably and assists degradation of the polymer.

Energy transfer in organic systems. XIII. Plastic scintillators

For pt.XII see ibid., vol.11, no.13, p.2301 (1978). Energy transfer has been investigated in polyvinyltoluene (PVT) scintillators containing pyrene p-terphenyl and naphthalene by measurement of scintillation pulse shapes and yields. It is concluded that there is an initial rapid diffusion of the excitation energy with solute molecules, residual monomer and PVT excimer sites acting as competing traps. At later times energy can transfer from residual monomer and PVT excimer traps to the solute either radiatively or via long-range resonance, and the efficiencies of these processes are governed by the absorption characteristics of the solute.

Suramin effects on macrophage phagolysosome formation and antimicrobial activity.

The effects of suramin on phagolysosome formation and antimicrobial activity of mouse peritoneal macrophages cultivated in vitro have been studied. Prolonged in vitro pretreatment of macrophages with high concentrations of suramin caused macrophages to form large fragile phagolysosomes in which the concentrations of the various lysosomal enzymes were inferred to be diminished. In addition, suramin-treated macrophages demonstrated enhanced exocytosis of acid phosphatase during phagocytosis of polyvinyl toluene spherules. However, suramin was found not to inhibit formation of phagolysosomes in macrophages that had ingested Listeria monocytogenes when those cells were examined by the electron microscope. Suramin pretreatment did not alter the ingestion or intracellular killing of Staphylococcus aureus or of a strain of L. monocytogenes that was essentially avirulent for mice, but did protect macrophages from destruction by virulent L. monocytogenes ingested in vitro, an effect that appeared to have been mediated through enhancement of the bacteriostatic potential of the macrophages. However, at a single dosage level, the drug did not alter the mortality of mice challenged with virulent L. monocytogenes.

Kinetic studies of phagocytosis. I. The serum independent particle uptake by PMN from patients with rheumatoid arthritis and systemic lupus erythematosus.

The initial phagocytic rate of IgG coated polyvinyl toluene latex particles was assayed for isolated PMN cells. The kinetic studies of phagocytosis were performed in serum-free medium using an electronic particle counter. The mean phagocytic rate for the reference group of apparently healthy individuals was 0.60 min-1. PMN cells from 5 of 26 patients with rheumatoid arthritis (RA) had subnormal values of particle ingestion rate, although the mean of the group was not significantly reduced compared to the controls. Correlation coefficient between the log of rheumatoid factor titer and phagocytic rate was 0.58 (P less than 0.001). During penicillamine treatment an increased rate of phagocytosis was observed in patients with RA. Granulocytes isolated from 17 patients with systemic lupus erythematosus (SLE) had a significantly increased (P less than 0.001) mean initial rate of phagocytosis (0.91 min-u). Two patients in this group had an acute exacerbation of disease activity and were treated with large doses of prednisone. An appreciable decline in phagocytic rate was observed during the intensive corticosteroid therapy.

Stimulation of the hexose monophosphate shunt independent of hydrogen peroxide and superoxide production in rabbit alveolar macrophages during phagocytosis

Phagocytosis and oxidative metabolism of human polymorphonuclear leukocytes (PMN) and rabbit alveolar macrophages (AM) were studied. Human PMN ingested a mean of 12 polyvinyl toluene latex particles (2 micrometer in diameter) per cell. There was stimulation of O2- and H2O2 production, light emission, and activation of the hexose monophosphate shunt during phagocytosis by human PMN. Rabbit AM ingested 51 latex particles (2 micrometer in diameter) per cell. There was no stimulation of the production of O2- and H2O2 or light emission associated with phagocytosis by rabbit AM, while the hexose monophosphate shunt was activated. Similar metabolic changes were obtained in both cell types when opsonized zymosan was used as phagocytic particles. 1-14C- glucoseoxidation was stimulated by H2O2 and methylene blue in both resting human PMN and rabbit AM. It is concluded that activation of the hexose monophosphate shunt in rabbit AM during phagocytosis is independent of O2- and H2O2 production.

Stimulation of the Hexose Monophosphate Shunt Independent of Hydrogen Peroxide and Superoxide Production in Rabbit Alveolar Macrophages During Phagocytosis

Phagocytosis and oxidative metabolism of human polymorphonuclear leukocytes (PMN) and rabbit alveolar macrophages (AM) were studied. Human PMN ingested a mean of 12 polyvinyl toluene latex particles (2 micrometer in diameter) per cell. There was stimulation of O2- and H2O2 production, light emission, and activation of the hexose monophosphate shunt during phagocytosis by human PMN. Rabbit AM ingested 51 latex particles (2 micrometer in diameter) per cell. There was no stimulation of the production of O2- and H2O2 or light emission associated with phagocytosis by rabbit AM, while the hexose monophosphate shunt was activated. Similar metabolic changes were obtained in both cell types when opsonized zymosan was used as phagocytic particles. 1-14C-glucoseoxidation was stimulated by H2O2 and methylene blue in both resting human PMN and rabbit AM. It is concluded that activation of the hexose monophosphate shunt in rabbit AM during phagocytosis is independent of O2- and H2O2 production.

Phagolysosome formation in normal and colchicine-treated macrophages.

Intracellular lysosomal fusion has been evaluated in cultivated mouse peritoneal macrophages by measurement of transfer of acid phosphatase to polyvinyltoluene (PVT)-containing phagolysosomes. Enzyme transfer was found to be directly and significantly related to the uptake of PVT and to be independent of time allowed for phagolysosome formation over time periods of 15 min to 18 h. In addition, the extent of transfer of lysosomal enzyme to phagolysosomes was unaffected by treatment of the cells with 10(-6) M colchicine, a dose which eradicates morphologically identifiable microtubules in this cell type within 2 h. The data indicate that intracellular fusion of lysosomes with phagosomes in the macrophage does not require formed microtubules and suggest that fusion occurs promptly after interiorization of inert particles.

Protection against Fluorescence Degradation of Polyvinyltoluene Excimer by uv Light

The protective effect of additive scintillator solutes on the degradation of polyvinyltoluene (PVT) excimer fluorescence arising from the irradiation by uv light has been investigated in monomer-free PVT systems. In these monomer-free systems, the fluorescence degradation of additive solutes is more intense than that of PVT excimer, and the degradation of PVT excimer fluorescence is protected by the addition of small amounts of anthracene or POPOP. The observed fluorescence degradation and protective effect are explained by a quenching model.

The microrheology of colloidal dispersions: I. The microtube technique

This paper describes a hydraulically-driven traveling microtube apparatus, designed and built with the aim of tracking the movements and interactions of individual colloidal particles and aggregates in Poiseuille flow through capillary tubes from 50 to 75 μm radius. The operation of the microtube device was tested using dilute dispersions of 2 μm diameter polyvinyl toluene latex spheres in water and biconcave, 8 μm diameter, human red cells in plasma. In the studies of aggregation phenomena, latex and coagulant were simultaneously infused into the flow tube, giving rise to a large variety of aggregate sizes and shapes. The formation and redistribution of aggregates with respect to size and geometry during flow down the tube was found to depend on the magnitude of the velocity gradient. In the case of blood, linear and branched chained rouleaux of red cells formed spontaneously during flow, but the number and size of aggregates decreased with increasing velocity gradient. The perturbation of the rotational orbits of individual latex aggregates by Brownian diffusion was also studied at velocity gradients from 2 to 30 sec −1 corresponding to rotary Péclet numbers from 6 to 90. The angular velocities of the axis of revolution of doublets and triplets of latex spheres fluctuated erratically, and over small time intervals the magnitude of the fluctuations correlated well with that measured in the absence of shear. The perturbation of the rotational orbit of single red cells and 2- and 3-cell rouleaux was much less pronounced than that of small latex aggregates.

In vitro induction of lysosomal enzymes by phagocytosis.

The in vitro induction of lysosomal enzymes by phagocytosis was demonstrated in cultivated mouse peritoneal macrophages. The contribution of each of several steps in the endocytic process to enzyme induction was examined. The enzymatic response after the uptake of equal numbers of erythrocytes (RBC) and nondigestible particles were compared. Phagocytosis of RBC produced a marked increase in the levels of acid phosphatase, beta-glucuronidase, and cathepsin D. Puromycin (1 microg/ml) inhibited the enzyme response. In contrast, phagocytosis of polyvinyl toluene, polystyrene, and insoluble starch particles produced no increase in macrophage lysosomal enzymes, although fusion of phagosomes with preexisting lysosomes occurred normally. The endocytic stimulus to synthesis of inducible lysosomal enzymes, therefore, occurred at or beyond the stage of digestion. Purified protein (bovine gamma globulin) aggregates and homopolymer coacervates of poly-l-glutamic acid: poly-l-lysine were effective inducers of lysosomal acid phosphatase, beta-glucuronidase, and cathepsin D, whereas homopolymers of the same D-amino acids were ineffective as inducers. Both the quantity of phagocytized substrate and its rate of enzymatic hydrolysis appear to control the level and persistance of lysosomal hydrolases.

Investigation of the thermal-oxidative degradation of certain methyl-substituted polymers

According to modern ideas about the thermal-oxidative degradation of polystyrene (PS), oxygen interacts predominantly with the α-hydrogen atom of the polystyrene chain, and the initial oxidation product is a hydroperoxide [1]. Investigation of the structure of oxidized PS by means of NMR, UV and IR spectroscopy has confirmed this mechanism, since aromatic ketones of the acetophenone type, formed by decomposition of the hydroperoxide, have been observed in the oxidized polymer [2,3]. In a study of methyl-substituted PS, in which one of the hydrogen atoms of the benzene ring was replaced by a methyl group (polyvinyltoluene (PVT)), it was found that, apart from considerable changes in the polymer properties [4,5], a substantial change occurs in its behaviour during thermal-oxidative degradation [6]. Thus, apart from the reaction between oxygen and the α-hydrogen atom of the vinyl chain, crosslinking of PVT occurs, the mechanism for which is, however, as yet insufficiently studied at the present time. The aim of the present investigation was a more profound study of the mechanism of thermal-oxidative degradation processes and structure-formation in PVT, and also in certain other methyl-substituted styrene polymers.

The use of the coulter counter for investigating the coagulation kinetics of mixed monodisperse particulate systems

The Coulter counter has been used to investigate the particle size distributions of polystyrene and polyvinyl toluene latices. The distributions have been shown to be closely log normal over the major part of their extent. Mixtures of two latex species have been examined in cases where overlap of the distributions does and does not occur. It has been shown that, in agreement with the conclusions of earlier workers, the measured distributions are broader than would be expected from the manufacturer's figures. The change in particle size profile of mixtures has been examined when coagulation occurs, and this has been compared to computer-predicted profiles. The significance of the results in terms of the coagulation behavior of supracolloidal suspensions is discussed.

Small-angle scattering by yeast cells—a comparison with the mie predictions

The angular dependence of light scattering by the sphere-like yeast cell in water was measured at angles up to 13°. The absolute value of the mean cell volume and the distribution of volumes about this mean were measured. For a mean cell diameter of about 4.9μ,α, circumference/wavelength, is 49.6 and 30.5, respectively, for λ ν = 400 and 650 mμ. Theoretical scattering curves for the cells were calculated from tabulated Mie coefficients and the particle size distribution. As controls, similar scattering measurements were made for calibrated polyvinyl toluene latex spheres. Scattering by the yeast cells was found to agree substantially with the predictions of the Mie equations for the homogeneous sphere.

Extinction efficiencies of large latex spheres

The extinction efficiency K of polyvinyl toluene latex spheres was measured over an effective particle size range which includes the first three principal extinction maxima (circumference/wavelength, α = 11.2–43.4). Spheres of diameters 3.49 μ and 2.051 μ were suspended in water and water-glycerol solutions to achieve relative refractive indices of about 1.19 and 1.11, respectively, and were illuminated with light of wavelengths 350–803 mμ. The experimental K-values are within about 3%-6% of those predicted by the Mie equations. Probable experimental sources of the differences are evaluated.

Ageing of plastic scintillators

Results are presented which show that counter resolution is reduced when the plastic phosphor is left in the scintillation counter for a period of 18 months. The deterioration of the plastic phosphor depends greatly on the method of use in the counters. It is thought that the aging may be prevented by a modification to the polymerization process since this aging is shown to occur in polyvinyl toluene base phosphors and not in polystyrene based phosphors. The performance of scintillation counters with new and aged plastic phosphors is illustrated by differential pulse height distribution in the region of the cosmic ray peak. (N.W.R.)

Additives Help Water Fight Fire Faster

RETURN TO ISSUEPREVNewsNEXTAdditives Help Water Fight Fire FasterSo far, sulfonated polyvinyl toluene is the most effective thickener, aluminum powder is the best opacifierCite this: Chem. Eng. News 1960, 38, 25, 54–57Publication Date (Print):June 20, 1960Publication History Published online6 November 2010Published inissue 20 June 1960https://doi.org/10.1021/cen-v038n025.p054Copyright © 1960 American Chemical SocietyArticle Views3Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) SUBJECTS:Additives,Redox reactions Get e-Alerts

Resins from formaldehyde. LI.1. Reaction of poly‐2,4‐dimethylstyrene with formaldehyde

AbstractThe reaction of 2,4‐dimethyl‐ethylbenzene with formaldehyde was carried out in acetic acid solution in the presence of perchloric acid. The values of the initial rate constants and the activation energy were nearly equal to those in the case of m‐xylene. The reactions of poly‐2,4‐dimethylstyrene, polyvinyl toluene and polystyrene with formaldehyde were carried out in benzene‐acetic acid in the presence of perchloric acid. The reactivity of poly‐2,4‐dimethylstyrene with formaldehyde was higher than that of polyvinyl toluene. Polystyrene did not react with formaldehyde.