College - Author 1

College of Engineering

Department - Author 1

Materials Engineering Department

Degree Name - Author 1

BS in Materials Engineering



Primary Advisor

Blair London, College of Engineering, Materials Engineering Department


In large scale composite manufacturing, voids and their frequency within prepreg materials play an important role in predicting the mechanical properties of a final composite laminate. The industry standard process for determining voids in composite materials is through resin digestion and resin ignition via ASTM D3171. One limitation to this standard is its ability to frequently produce negative void volume values in quality control testing, due to the calculation sensitivity of input resin and fiber densities. For this reason, Toray Advanced Composites wanted to investigate the process steps of ASTM D3171 to determine if discrepancies in resin density data may be leading to negative void volumes in their EX-1515 cyanate ester resin system. In order to analyze the matrix density, three groups of materials were investigated including: neat EX-1515 resin, EX-1515/CN-60 composite, and EX-1515/Astroquartz composite. All three materials underwent dimensional and specific gravity density measurements, in addition to optical microscopy. In combination with data from resin ignition and digestion, the density data revealed that original assumed density for EX-1515 was lower than the actual density of the resin system, which led to the prevalence of negative void volume calculations. Furthermore, the results of the project revealed the importance of there being a range of density values for composite resin systems due to the high sensitivity of the process steps and calculations found within ASTM D3171.

Available for download on Wednesday, June 03, 2026