Astm D 3532 – 99 pdf free download

Standard Test Method for
Gel Time of Carbon Fiber-Epoxy Prepreg1

This standard is issued under the fixed designation D 3532; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of the last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the Department of Defense.

1. Scope

1.1 This test method covers the determination of gel time of
carbon fibre-epoxy tape and sheet. The test method is suitable
for the measurement of gel time of resin systems having either
high or low viscosity.

1.2 The values stated in SI units are to be regarded as
standard. The values in parentheses are for reference only.

1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Summary of Test Method

2.1 A specimen of prepreg material approximately 5 mm
(0.25 in.) square is placed between microscope cover glasses
on a hot plate preheated to either of two test temperatures, 120
or 175°C (250 or 350°F). Pressure is applied to the specimen
through the cover glass with a wood pick to form a bead of resin
at the edge of the cover glass. The time from the application of
heat until the resin ceases to form strings by contact with the
pick is noted and reported as gel time.

3. Significance and Use

3.1 This test method can be used to obtain the gel time of
resin squeezed from prepreg tape or sheet material. This test is
a useful measure for material acceptance.

3.2 The gel time will vary with the test temperature. The
temperatures specified in this test method are two of many
temperatures often used in processing epoxy prepreg material.
If other test temperatures are used, this is to be clearly noted as
indicated in 9.1.2.

3.3 Gel time is not recommended as a measure of outline
(unacceptable degree of cross-linking). Use Resin Flow Test
Method D 3532, or Dynamic Viscosity Practice D 4473.