GB/T 8810-2005Determination of water absorption of rigid cellular plastics (English PDF)

Foreword

This standard modifies and adopts ISO 2896.2001 "Rigid cellular plastics -

Determination of water absorption".

The main differences between this standard and ISO 2896.2001 are as follows.

- DELETE the phrase "unless otherwise stated" in the test environment;

- ADD the accuracy of volume measurement "V0 accurate to 0.1 cm3";

- USE the sentence "Remove the specimen from the water and remeasure the

dimensions immediately; wipe off surface moisture with filter paper before

measurement" to replace that "Remove the specimen from the water and remeasure

the dimensions within 4 hours of removal".

The relevant technical differences are incorporated into the text and marked with a

vertical single line in the margin of the clauses to which they pertain. A summary of

these technical differences and their reasons is provided in Appendix C for reference.

This standard replaces GB/T 8810-1988 "Test method for water absorption of rigid

cellular plastics".

The main changes, as compared to GB/T 8810-1988, are as follows.

- CHANGE the standard name;

- ADD a foreword;

- INCLUDE the Appendix B in the main text of the standard;

- DELETE the test condition "water temperature (23 ± 2) °C";

- CHANGE the phrase "Accurate to 0.01 g" for the balance and weighing to

"Accurate to 0.1 g";

- ADD that "V0 accurate to 0.1 cm3";

- ADD the instructions for volume measurement after immersion;

- ADD the precision;

- ADD the clauses regarding uncertain accuracy;

- ADD the derivation of the formula for calculating the average bubble diameter D;

- CHANGE the phrase "Specimen volume not greater than 500 cm3" in the cross-

section bubble volume correction to "Specimen volume not less than 500 cm3";

Determination of water absorption of rigid cellular plastics

1 Scope

This standard specifies the method for determining the water absorption rate of rigid

cellular plastics. by measuring the buoyancy of the sample after immersion in water for

50 mm for 96 h.

It specifies the corrections for sample volume change and volume correction for the

pores on the cut surface of the sample.

2 Normative references

The provisions in following documents become the provisions of this Standard through

reference in this Standard. For the dated references, the subsequent amendments

(excluding corrections) or revisions do not apply to this Standard; however, parties who

reach an agreement based on this Standard are encouraged to study if the latest versions

of these documents are applicable. For undated references, the latest edition of the

referenced document applies.

GB/T 2918-1998 Plastics. Standard atmospheres for conditioning and testing (idt

ISO 291.1997)

GB/T 6342-1996 Cellular plastics and rubbers - Determination of linear dimensions

(idt ISO 1923.1981)

3 Principle

The water absorption rate of a material is determined, by measuring the buoyancy of a

specimen immersed in distilled water for a certain period of time.

4 Immersion solution

Distilled water that has been left to stand for at least 48 hours after distillation.

5 Test apparatus

6 Specimens

7 Test method