AS 2498.8-1991

Methods of testing rigid cellular plastics Determination of water absorption

Standards Australia

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1 - AS 2498.8-1991 METHODS OF TESTING RIGID CELLULAR PLASTICS - DETERMINATION OF WATER ABSORPTION
1 - PREFACE
1 - FOREWORD
1 - METHOD
1 - 1 SCOPE
1 - 2 APPLICATION
1 - 3 REFERENCED DOCUMENT
1 - 4 PRINCIPLE
2 - 5 APPARATUS
2 - 5.1 Balance
2 - 5.2 Underwater weighing jig
2 - 5.3 Immersion tank
2 - 5.4 Test specimen rack
2 - 5.5 Balance platform
2 - 5.6 Forced-air circulating oven
2 - 5.7 Dessicator
2 - 5.8 Low-permeability plastic film
2 - 5.9 Measuring instruments
2 - 6 TEST SPECIMENS
2 - 6.1 Dimensions
2 - 6.2 Preparation
2 - 6.3 Number
2 - 6.4 Conditioning
2 - 7 PROCEDURE
3 - 8 CORRECTION FOR SWELLING AND CUT SURFACE CELLS
3 - 8.1 Procedure A (uniform swelling)
3 - 8.2 Procedure B (non-uniform swelling)
4 - 9 CALCULATION OF RESULTS
4 - 9.1 Original volume
4 - 9.2 Surface area
4 - 9.3 Percentage water absorbed
5 - 10 REPORT
6 - APPENDIX A - DETERMINATION OF AVERAGE CELL DIAMETER
6 - A1 SCOPE
6 - A2 PRINCIPLE
6 - A3 APPARATUS
6 - A3.1 Slicer
6 - A3.2 Slide assembly
6 - A3.3 Projector
6 - A4 SPECIMENS
6 - A4.1 Number of specimens
6 - A4.2 Dimensions
6 - A5 PROCEDURE
6 - A6 CALCULATIONS
6 - A7 DERIVATION OF RELATIONSHIP BETWEEN CELL DIAMETER AND CELL CHORD LENGTH

Abstract

Specifies a method for determining the water absorption of rigid cellular plastics by measuring the change in buoyant force resulting from immersion in distilled water.

Scope

This Method sets out a method for determining the water absorption of rigid cellular plastics by measuring the change in buoyant force resulting from immersion in distilled water.
NOTES:
1 Some materials may absorb significant additional amounts of water when immersed for longer than 96 h, or under a greater hydrostatic head.
2 If a full assessment of the water absorption characteristics of a rigid cellular plastics is required, it is essential to make measurements over a range of immersion periods and plot a graph of water absorption against time.