Document Type

Conference Paper

Publication Date


Publication Source

Proceedings of the SAMPE 2023 Conference and Exhibition


Cyanate ester resins are sometimes mixed with lower cost epoxy monomers to modify cost, toughness, and processing capabilities. Despite the high performance of these thermosetting polymers, flame retardancy remains an issue. This study examined blends of three different commercial cyanate ester monomers (LVT-100, LECy, and XU-71787.02) and diglycidyl ether of bisphenol A (DGEBA) at 50/50 wt% of each type. The blends were successfully reacted with two reactive flame retardants (FR): 9,10-dihydro-9-ox-9-phosphaphenanthrene-10-oxide (DOPO) and poly(m-phenylene methylphosphonate) (PMP) at phosphorus contents ranging from 0 to 3 wt%. The curing behavior of EP/CE blends was investigated using differential scanning calorimetry (DSC). It was found that introducing phosphorus into EP/CE blends lowered both the onset reaction temperature and the glass transition temperature Tg for all blends. TGA data revealed that the addition of PMP and DOPO to EP/CE blends resulted in a linear decrease in the onset decomposition temperatures of LVT and LECy blends, with a maximum drop of 36 °C in the EP/XU/DOPO blend compared to the EP/XU baseline blend. In addition, TGA results revealed that the introduction of PMP into EP/CE blends improved the char yield of the blends by 24%, while the DOPO reduced the char residue of the blend by 24% compared to the baseline EP/CE blends. Incorporating PMP and DOPO as reactive FR into the EP/CE network structure has been successfully investigated.

Document Version

Published Version


The document is made available with the permission of the authors and SAMPE. Permission documentation is on file. DOI:


Society for the Advancement of Material and Process Engineering – North America


Cyanate ester, Epoxy blend, Flame retardant, Thermal stability, curing behavior