Permissible diffusion resistance of polymer coatings against water vapour and its diffusion effective film thickness

2004 ◽  
pp. 347-352 ◽  
Author(s):  
Robert Engelfried
Keyword(s):  
Film Thickness ◽  
Water Vapour ◽  
Polymer Coatings ◽  
Diffusion Resistance

Untersuchungen zum Diffusionswiderstand von Holzwerkstoffen | Diffusion resistance of timber materials

2005 ◽  
Vol 156 (3-4) ◽  
pp. 100-103
Author(s):  
Rudolf Popper ◽  
Peter Niemz ◽  
Gerhild Eberle
Keyword(s):  
Relative Humidity ◽  
Water Vapour ◽  
Middle Lamella ◽  
Solid Wood ◽  
Diffusion Resistance ◽  
Water Vapour Diffusion ◽  
Wood Panels ◽  
Vapour Diffusion ◽  
Wet Climate ◽  
Panel Thickness

The water vapour diffusion resistance of timber materials were tested in a wet climate (relative humidity ranging from 100%to 65% at 20 °C) and in a dry climate (relative humidity ranging from 0% to 65% and from 0% to 35% at 20 °c) with variation by relative humidity and vapour pressure gradient. The diffusion resistance of multilayer solid wood panels lies under or within the range of the solid wood (spruce), tending even to a lower range. This can be attributed to the loosely inserted middle lamella of the used solid wood panels, which were not correctly glued by the manufacturer. The diffusion resistance of the solid wood panels increases with decreasing moisture content and decreasing panel thickness, as well as with increasing water vapour gradient from 818 to 1520 Pa. There were clear differences between the tested timber materials. The diffusion resistance of particle composites is strongly dependent on the specific gravity. Due to laminar particles OSBs(Oriented Strand Boards) have a larger diffusion resistance than chipboards. The water vapour diffusion resistance of OSBs lies within the range of plywood.

Film thickness limits of a buckling-based method to determine mechanical properties of polymer coatings

2021 ◽  
Vol 582 ◽  
pp. 227-235
Author(s):  
Elina Niinivaara ◽  
Johanna Desmaisons ◽  
Alain Dufresne ◽  
Julien Bras ◽  
Emily D. Cranston
Keyword(s):  
Mechanical Properties ◽  
Film Thickness ◽  
Polymer Coatings

Effects of exposure on water relations and photosynthesis of western hemlock in habitat forms

1976 ◽  
Vol 6 (1) ◽  
pp. 40-48 ◽  
Author(s):  
R. A. Keller ◽  
E. B. Tregunna
Keyword(s):  
Light Intensity ◽  
Water Content ◽  
Water Vapour ◽  
Western Hemlock ◽  
Diffusion Resistance ◽  
The Sun ◽  
Evaporative Demand ◽  
Photosynthetic Rates ◽  
Water Vapour Diffusion ◽  
Vapour Diffusion

Measurements of relative turgidity, transpiration rates, and photosynthetic rates on sun-grown and shade-grown western hemlock (Tsugaheterophylla (Raf.) Sarg.) were used to indicate effects of varying degrees of exposure.The sun-adapted form had low photosynthetic rates but maintained its water content under conditions of high evaporative demand. The shade-adapted form desiccated under exposed conditions, and in contrast with the sun-adapted form, its water vapour diffusion resistance decreased with increasing light intensity.

Hygric Properties of HPC with Natural Pozzolana

2016 ◽  
Vol 677 ◽  
pp. 93-97 ◽  
Author(s):  
Jaroslava Koťátková ◽  
Monika Čáchová ◽  
Dana Koňáková ◽  
Eva Vejmelková
Keyword(s):  
Water Vapour ◽  
High Performance ◽  
High Performance Concrete ◽  
Diffusion Resistance ◽  
Supplementary Cementitious Material ◽  
Water Vapour Transport ◽  
Water Vapour Diffusion ◽  
Natural Pozzolana ◽  
Vapour Diffusion ◽  
Liquid Water Transport

The water vapour transport and the liquid water transport of high performance concrete (HPC) with the content of natural pozzolana are the described in this paper. Studied properties are presented by means of water vapour diffusion coefficient, water vapour diffusion resistance factor and absorption coefficient respectively. The natural pozzolana (NP), namely natural zeolite, is used as supplementary cementitious material which affects the durability properties of the end product. The obtained results revealed the effectiveness of NP in the terms of both studied properties when used in small amounts, i.e. at about 20% of cement weight. On the other hand substitutions higher than 40% result in worsening of the resistance of the concrete to water and water vapour ingress and its movement trough the material.

The Structure and Relaxation of Thin Polymer Layers on Solid Surfaces

1976 ◽  
Vol 49 (5) ◽  
pp. 1311-1323 ◽  
Author(s):  
Y. S. Lipatov
Keyword(s):  
Mechanical Properties ◽  
Film Thickness ◽  
Solid Surface ◽  
Molecular Mobility ◽  
Volume Ratio ◽  
Polymer Coatings ◽  
Relaxation Behavior ◽  
Surface Layers ◽  
Thin Polymer ◽  
Chain Conformations

Abstract In conclusion, we can say that the properties of thin polymer films and their relaxation behavior are strongly dependent on their thickness. This is related to the restriction of molecular mobility at the phase boundary (independent of its nature) as a result of the reduced number of possible chain conformations. The less the polymer thickness, the more pronounced is the contribution of surface layers with diminished molecular mobility to the mechanical properties. This statement may be illustrated by Figure 12, which shows the dependence of the elastic modulus and surface-to-volume ratio on film thickness. Diminishing film thickness leads to increase in film rigidity, beginning at the point where the surface-to-volume ratio increases sharply. This suggests that the effect is associated with change in mechanical properties of thin surface layers, which contributes significantly to total mechanical properties. We have other data which show also that the relaxation spectrum of a film is changed when its thickness changes. The findings discussed above indicate that the solid surface has a noticeable and complex effect on the properties and relaxation behavior and relaxation time spectra of polymer coatings on solid surface, both inorganic and organic. The principal reasons for these changes are the adsorption interaction with the solid surface, decrease of molecular mobility, and strong intermolecular interaction transferring the influence of the solid surface to more remote layers of polymer.

scholarly journals Research of Wood Waste as a Potential Filler for Loose-Fill Building Insulation: Appropriate Selection and Incorporation into Polyurethane Biocomposite Foams

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5336
Author(s):  
Nerijus Augaitis ◽  
Saulius Vaitkus ◽  
Sylwia Członka ◽  
Agnė Kairytė
Keyword(s):  
Thermal Conductivity ◽  
Water Absorption ◽  
Water Vapour ◽  
Wood Waste ◽  
Diffusion Resistance ◽  
Water Vapour Diffusion ◽  
Recycling Potential ◽  
Water Vapour Resistance ◽  
The Stability ◽  
Loose Fill

Currently, the recycling potential of wood waste (WW) is still limited, and in a resource efficiency approach, recycling WW in insulation materials, such as polyurethane (PUR), appears as an appropriate solution. It is known that the quality of WW is the main aspect which influences the stability of the final products. Therefore, the current study analyses different WW-based fillers as possible modifiers for polyurethane biocomposite foams for the application as loose-fill materials in building envelopes. During the study of WW-based fillers, it was determined that the most promising filler is wood scobs (WS) with a thermal conductivity of 0.0496 W/m·K, short-term water absorption by partial immersion—12.5 kg/m2, water vapour resistance—0.34 m2·h·Pa/mg and water vapour diffusion resistance factor—2.4. In order to evaluate the WS performance as a filler in PUR biocomposite foams, different ratios of PUR binder and WS filler (PURb/WS) were selected. It was found that a 0.40 PURb/WS ratio is insufficient for the appropriate wetting of WS filler while a 0.70 PURb/WS ratio produced PUR biocomposite foams with the most suitable performance: thermal conductivity reduced from 0.0523 to 0.0476 W/m·K, water absorption—from 5.6 to 1.3 kg/m2, while the compressive strength increased from 142 to 272 kPa and the tensile strength increased from 44 to 272 kPa.

Planarization with Cyclotene™ 3022 (BCB) Polymer Coatings

1993 ◽  
Vol 308 ◽  
Author(s):  
T.M. Stokich ◽  
C.C. Fulks ◽  
M.T. Bernius ◽  
D.C. Burdeaux ◽  
P.E. Garrou ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Film Thickness ◽  
Polymer Film ◽  
Polymer Coatings ◽  
Polymer Thin Film ◽  
Film Coatings ◽  
Thin Film Coatings ◽  
Processing Procedure ◽  
The Mean

ABSTRACTThis work examines the planarization of polymer thin film coatings derived from Cyclotene™ 3022 prepolymer resins. Cyclotene™ 3022 is a divinyl siloxane bis-benzocyclobutene prepolymer (DVS-BCB, CAS 117732-87-3). It is used primarily as a dielectric in microelectronics applications.Using profilometry, planarization measurements have been made on thin films spun over features consisting of lines and trenches. Feature widths have been varied from 2 to 1000 μm and the feature depths and film thickness have been varied from 1 to 16 μm. Effects of the processing procedure, resin concentration and resin additives have been explored. Local (versus global) planarization will be discussed.Planarization has been found to depend on all feature dimensions and the polymer film thickness. Lines or other structures having a width of 100 μm or less can be planarized to 90% or better with standard commercial formulations of Cyclotene™ 3022, provided that the mean film thickness is twice the line-height or feature-depth. Metals such as Al, Cu, Cr and Ti can all be planarized to this degree; however, surface preparations may influence the result.

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