5.1 This test method can be used to obtain the fiber content, fiber areal weight, matrix content or matrix solids content. Knowledge of these results is useful in specifying material systems and in developing optimum manufacturing processes. Where volatiles content is consistent and not critical to process, matrix content shall be used.

5.2 This test method is limited to reinforcement constituents that do not change mass upon exposure to the matrix removal procedure and limited to matrix constituents that are fully removed by the matrix removal procedure. In the event of experiencing either limitation, an agreement should be reached with the end-user as to how to proceed.

1.1 This test method covers the determination of the fiber content, fiber areal weight, matrix solids content and matrix content of composite material prepregs. Optionally, the matrix solids content can also be determined after a volatiles content has been established. Volatiles content, if appropriate and required, is determined by means of Test Method D3530.

1.2 Procedure A of this test method applies to composite prepreg of primarily thermosetting matrices that can be extracted in organic solvent. The reinforcement and filler must be substantially insoluble in the selected extraction reagent. This procedure may also be used for the same purposes to extract other matrix material types.

1.3 Procedure B of this test method uses ignition loss of a composite prepreg matrix and applies to organic matrix composite systems containing reinforcing fibers that do not change mass when exposed to the matrix combustion method.

1.4 This test method assumes a two-part material system (plus volatiles) and does not distinguish between hybrid reinforcements or matrices. Use with hybrid composites is limited to determination of total reinforcement or total matrix content.

1.5 Matrix solids determination for Procedures A or B uses Test Method D3530 to determine volatiles content.

1.6 Alternate techniques for determining constituent content include Test Methods C613 (resin content by Soxhlet extraction) and D3171 (used principally for consolidated laminates).

1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.8 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. Specific precautionary information is given in Sections 8 and 9.