Sequential interpenetrating polymer networks from bisphenol A based cyanate ester and bimaleimide: Properties of the neat resin and composites
✍ Scribed by C. P. Reghunadhan Nair; Tania Francis; T. M. Vijayan; K. Krishnan
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 207 KB
- Volume
- 74
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
Blends of varying composition of a bisphenol A based cyanate ester-viz., 2,2-bis-(4-cyanatophenyl) propane (BACY)-and a bisphenol A based bismaleimideviz., 2,2-bis[4-(4-maleimido phenoxy) phenyl] propane (BMIP)-were cured together in a sequential manner to derive bismaleimide-triazine network polymers. Enhancing the bismaleimide content was conducive for decreasing the tensile properties and improving both the flexural strength and fracture toughness of the cyanate ester-rich neat resin blends. Although DMA analyses of the cured blend indicated a homogeneous network for the cyanate ester dominated compositions, microphase separation occurred on enriching the blend with the bismaleimide. Addition of bismaleimide did not result in any enhancement in T g of the blend. Interlinking of the two networks and enhancing crosslink density through coreaction with 4-cyanatophenyl maleimide impaired both the mechanical and fracture properties of the interpenetrating polymer network (IPN), although the T g showed an improvement. Presence of the bismaleimide was conducive for enhancing the mechanical properties of the composites of the cyanate ester rich blend, whereas a higher concentration of it led to poorer mechanical properties due to the formation of a brittle interphase. The IPNs showed reduced moisture absorption and low dielectric constant and dissipation factor, the latter properties being independent of the blend composition.