Determination of the Moisture Uptake Mechanism in Closed Cell Polymeric Structural Foam during Hygrothermal Exposure

2004 ◽  
Vol 38 (15) ◽  
pp. 1345-1365 ◽  
Author(s):  
J. S. Earl ◽  
R. A. Shenoi
Keyword(s):  
Moisture Uptake ◽  
Uptake Mechanism ◽  
Structural Foam ◽  
Closed Cell

scholarly journals Investigation of Flame Retardant rPET Foam

2019 ◽  
Vol 64 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Veronika Anna Szabó ◽  
Gábor Dogossy
Keyword(s):  
Flame Retardant ◽  
Chain Extender ◽  
Environmental Load ◽  
Structural Foam ◽  
Pet Bottles ◽  
Beverage Containers ◽  
Appropriate Treatment ◽  
Closed Cell ◽  
Research Goal ◽  
Industrial Use

The use of plastics in the food and the packaging industries continuously is increasing. In these areas of use the product’s life cycle is short, therefore it quickly turns into waste. The polyethylene terephthalate (PET) - the material that is used as beverage containers - are the material with the greatest environmental load. The physical recycling of PET bottles in large quantities was the research goal. During the work with the help of chemical foaming a closed cell structural foam from PET bottle was produced. The research was carried out with upcycling using chain extender and impact modifier additives. For industrial use a bromine-based flame retardant was used and excellent flame retardancy was achieved. Based on the results obtained, the material previously managed as waste, with the appropriate treatment can be involved into the manufacturing of new products.

Experimental Determination of Mechanical Properties of Aluminium Foams Using Digital Image Correlation

2014 ◽  
Vol 601 ◽  
pp. 254-257 ◽  
Author(s):  
Tudor Voiconi ◽  
Emanoil Linul ◽  
Liviu Marsavina ◽  
Jaroslav Kováčik ◽  
Marcin Kneć
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Yield Stress ◽  
Digital Image ◽  
Compressive Loading ◽  
Image Correlation ◽  
Compression Tests ◽  
Closed Cell

This paper presents an experimental characterization of three different types of closed-cell aluminium alloy foams (AlMg1Si0.6, AlSi12Mg0.6 and AlMg0.6Si0.3) under static compressive loading. This study was carried out on half-cylindrical specimens with skin. The influence of foam density on compressive behaviour was investigated for densities ranging from 430 kg/m3 to 935 kg/m3. The compression tests were performed at room temperature (23°C) with a constant crosshead speed of 0.5 mm/min. Strain distribution, yield stress and compressive modulus values were recorded using Digital Image Correlation. Experimental results show that the mechanical properties (Youngs Modulus, yield stress and plateau stress) increase with density.

Polyethylene-Kevlar Composite Foams III: Torsion Properties

2005 ◽  
Vol 24 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Yaolin Zhang ◽  
Denis Rodrigue
Keyword(s):  
Aspect Ratio ◽  
Shear Modulus ◽  
Void Fraction ◽  
Compression Molding ◽  
High Density ◽  
Polymer Foams ◽  
Structural Foam ◽  
Polyethylene Composite ◽  
Composite Foams ◽  
Closed Cell

High density closed-cell Kevlar-polyethylene composite foams (17 - 30% void fraction) were prepared by compression molding and characterized via torsion rectangular tests in order to determine the effect of thin unfoamed skins and Kevlar content on shear modulus. It was found that structural foam models gave better results than uniform foam models indicating that thin skins have an important effect on the shear modulus of polymer foams. The normalized modulus of our composite structural foams can be predicted by a sandwich model in combination with Berlin's approach and Rosen's model for the aspect ratio of the fibres.

scholarly journals Properties of magnesium oxide boards used as sheathing in exterior walls

2019 ◽  
Vol 282 ◽  
pp. 02091
Author(s):  
Stefanie Wøhler Nielsen ◽  
Carsten Rode ◽  
Tommy Bunch-Nielsen ◽  
Kurt Kielsgaard Hansen ◽  
Wolfgang Kunther ◽  
...  
Keyword(s):  
Magnesium Oxide ◽  
Salt Water ◽  
Ambient Air ◽  
Dry Mass ◽  
Optical Microscope ◽  
Visual Observation ◽  
Moisture Uptake ◽  
Vapour Permeability ◽  
Scanning Electron

Sheathing boards based on magnesium oxide (MgO) became very popular in the Danish market around the year 2010. However, it was realized a few years later that they condensed humidity from ambient air. The leakage from the boards led to severe problems with corrosion of metallic components and moisture uptake and degradation of wooden members. The boards have been banned from use in the Danish market since 2015, while damage cases valuing around 370 million EUR still need to be reconciled [1]. The binder in MgO board is formed by a chemical reaction between MgO and MgCl2. However, MgSO4 is a possible alternative to MgCl2, and such boards may have smaller moisture uptake, to reduce this issue. This paper gives an account of recent activities to compare properties of MgO boards, based on chlorides or sulphates. The investigations comprise: (1) Analysis of elemental composition and crystalline components, (2) Examination in optical microscope and scanning electron microscope, (3) Determination of moisture retention and water vapour permeability, (4) Analysis of chemical composition of leaked salt water from boards, and (5) Visual observation of decomposition and determination of dry mass change after exposure to high humidity.

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