Diffusion of Organic Vapors into Polyvinyl Acetate<sup>1</sup>

Kokes, R. J.; Long, F. A.

doi:10.1021/ja01120a011

Cited by 114 publications

(37 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The diffusion coefficient of allyl chloride in polyvinyl acetate a t 4OoC., obtained from steady-state permeation measurements,' was found to increase more rapidly with concentration of diff usate than diffusion coefficients calculated from sorption kinetics. 2 The difference was interpreted as due to slow relaxation of the polymer so that the steady-state measurements referred to polymer in which all stress had decayed by viscous flow whereas the sorption kinetics were influenced by residual elastic stress.…”

Section: Introductionmentioning

confidence: 99%

Diffusion of allyl chloride in polyvinyl acetate. Part II. The transient state of permeation

Meares

1958

J. Polym. Sci.

View full text Add to dashboard Cite

The permeation rate of allyl chloride through polyvinyl acetate films has been studied as a function of time during the transient period preceding the establishment of steady states of permeation. It was found that two distinct processes could be distinguished. When the ingoing pressure of allyl chloride was changed from a value at which a steady state had been established to a new value, there was a gradual change in the permeation rate to a new steady value. Depending upon the initial and final pressures this change required from several hours to several weeks. When the initial ingoing pressure was small or zero there was a large and immediate increase in the permeation rate when the ingoing pressure was increased. This rapid rate decreased over periods which ranged from about three hours at low ingoing pressures to a few minutes for higher ones, and died away before the more gradual increase in rate had begun to take effect. Using the equations of Frisch, the time lags for transition between pairs of steady states have been calculated, from previously determined sorption and diffusion data, and compared with the observed values. The calculated values were usually smaller than the observed ones. The discrepancy was most serious at low vapor concentrations and decreased with increasing concentration. For concentrations greater than 1 × 10−3 mole cm.−3 there was a close agreement. For comparable concentrations, the discrepancy was less marked for decreasing than for increasing ingoing pressure and was also less for thin membranes than for thicker ones. These observations are consistent with the theory that the swelling of the membrane which accompanies the sorption of vapor gives rise to elastic stresses which slowly decay by viscous movements within the polymer. The initial jump in permeation rate proved more difficult to study. As far as could be determined it occurred instantaneously. When plotted against logarithmic time, S‐shaped curves were obtained very similar in appearance to elastic stress decay curves observed for polymers and predicted theoretically for a series of Maxwell units with a wide distribution of relaxation times. This suggests that the high permeability may arise from lateral strains set up when an instantaneous swelling takes place at the ingoing face of the membrane on the admission of more vapor. The instantaneous stress then decays by elastic motions of segments of polymer molecules, over a period determined by the temperature and initial sweller concentration, and so reduces the high permeation rate. For initially unswollen polyvinyl acetate at 40° the time for half‐decay of the permeation rate was agout 25 minutes for a membrane 32 μ thick. It was found that the peak permeation rate increased as successive experiments were performed with the same membrane. This suggested that permeation through a membrane clamped in a diffusion cell produced orientation parallel to the membrane surface. It has not yet been possible to confirm this.

show abstract

Section: Introductionmentioning

confidence: 99%

Diffusion of allyl chloride in polyvinyl acetate. Part II. The transient state of permeation

Meares

1958

J. Polym. Sci.

View full text Add to dashboard Cite

show abstract

“…In this work, we apply the VFT equation for D w (T , 1) using the values found by Smith and Kay (1999) (Kokes and Long, 1953;Long and Thompson, 1955;Kumins et al, 1957;Yasuda and Stannett, 1962;Schatzberg, 1965;Hardy, 1967;Demertzis and Kontominas, 1989;Tromp et al, 1997). Table A1 lists the activation energies of our other model systems, which in general are slightly higher than those reported in the literature.…”

Section: A2 Parameterization Of D W (T a W )mentioning

confidence: 99%

Viscous organic aerosol particles in the upper troposphere: diffusivity-controlled water uptake and ice nucleation?

Lienhard

Huisman

Krieger³

et al. 2015

Atmos. Chem. Phys.

119

190

View full text Add to dashboard Cite

Abstract. New measurements of water diffusion in secondary organic aerosol (SOA) material produced by oxidation of α-pinene and in a number of organic/inorganic model mixtures (3-methylbutane-1,2,3-tricarboxylic acid (3-MBTCA), levoglucosan, levoglucosan/NH 4 HSO 4 , raffinose) are presented. These indicate that water diffusion coefficients are determined by several properties of the aerosol substance and cannot be inferred from the glass transition temperature or bouncing properties. Our results suggest that water diffusion in SOA particles is faster than often assumed and imposes no significant kinetic limitation on water uptake and release at temperatures above 220 K. The fast diffusion of water suggests that heterogeneous ice nucleation on a glassy core is very unlikely in these systems. At temperatures below 220 K, model simulations of SOA particles suggest that heterogeneous ice nucleation may occur in the immersion mode on glassy cores which remain embedded in a liquid shell when experiencing fast updraft velocities. The particles absorb significant quantities of water during these updrafts which plasticize their outer layers such that these layers equilibrate readily with the gas phase humidity before the homogeneous ice nucleation threshold is reached. Glass formation is thus unlikely to restrict homogeneous ice nucleation. Only under most extreme conditions near the very high tropical tropopause may the homogeneous ice nucleation rate coefficient be reduced as a consequence of slow condensed-phase water diffusion. Since the differences between the behavior limited or non limited by diffusion are small even at the very high tropical tropopause, condensed-phase water diffusivity is unlikely to have significant consequences on the direct climatic effects of SOA particles under tropospheric conditions.

show abstract

“…For a given polymer. 'Aitken & Barrer (1954); ' 'Hayes & Park (1955);'^Kokes & Long (1953); 'Coughlin, Maurutz & Storey (1990).…”

Section: Size-dependent Organic Soiute Mobiiity In Cuticiesmentioning

confidence: 99%

Diffusion in plant cuticles as affected by temperature and size of organic solutes: similarity and diversity among species

Baur

Buchholz

Schönherr

1997

Plant Cell & Environment

View full text Add to dashboard Cite

Ptant, Cell and Environment (^997) 20,[982][983][984][985][986][987][988][989][990][991][992][993][994],viv In this range, solute mobilities increased up to 1000-fold, which corresponds to temperature coefficients Qio of 3 (IAA in P. armeniaca) to 14 (cholesterol in fi. hetix). For most species, Arrhenius graphs showed good linearity up to 40 °C, and up to 78 °C for some species, while for others activation energies declined with increasing temperature. However, no distinct phase transitions caused by sudden structural changes in the CM were observed. In three species we examined whether heating to 70 °C changed solute mobility irreversibly by comparing Arrhenius graphs for two successive experiments with the same CM. The two graphs were very similar for P, taurocerasus, while mobilities in the second graph were somewhat reduced for C. aurantium and greatly increased (at 25 and 35 °C) for H. helix. This indicates rearrangements of at least some wax constituents when heated to high temperatures. The activation energies of diffusion (/i|,) ranged from 75 to 189 k. F moP' depending on .species and .solute size. Size selectivity and variability between cuticles decreased witb increasing temperature, and this is caused by differences in li|,. An excellent correlation between the pre-exponential factor of the Arrhenius equation and /i,, was observed, which is evidence that organic solutes differing greatly in molecular size (130-349 cm' moP') and cuticle/water partition coefficient (25-10*") use similar diffusion paths in the CM of all 12 plant species tested. Diffusion occurs in regions with identical phy.sicochemical properties and differs only in magnitude.

show abstract

Diffusion of Organic Vapors into Polyvinyl Acetate¹

Cited by 114 publications

References 5 publications

Diffusion of allyl chloride in polyvinyl acetate. Part II. The transient state of permeation

Diffusion of allyl chloride in polyvinyl acetate. Part II. The transient state of permeation

Viscous organic aerosol particles in the upper troposphere: diffusivity-controlled water uptake and ice nucleation?

Diffusion in plant cuticles as affected by temperature and size of organic solutes: similarity and diversity among species

Contact Info

Product

Resources

About

Diffusion of Organic Vapors into Polyvinyl Acetate1

Cited by 114 publications

References 5 publications

Diffusion of allyl chloride in polyvinyl acetate. Part II. The transient state of permeation

Diffusion of allyl chloride in polyvinyl acetate. Part II. The transient state of permeation

Viscous organic aerosol particles in the upper troposphere: diffusivity-controlled water uptake and ice nucleation?

Diffusion in plant cuticles as affected by temperature and size of organic solutes: similarity and diversity among species

Contact Info

Product

Resources

About

Diffusion of Organic Vapors into Polyvinyl Acetate¹