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Liquid crystalline cyanurate thermosets through cyclotrimerisation of novel triaromatic dicyanates
Author(s) -
Mormann Werner,
Kuckertz Christian
Publication year - 1998
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19980501)199:5<845::aid-macp845>3.0.co;2-o
Subject(s) - thermosetting polymer , monomer , glass transition , liquid crystal , mesophase , polymer chemistry , hydroquinone , materials science , curing (chemistry) , chemistry , organic chemistry , composite material , polymer , optoelectronics
Three novel triaromatic dicyanates, hydroquinone bis(4‐cyanatobenzoate) ( 1 ), methylhydroquinone bis(4‐cyanatobenzoate) ( 2 ), and trimethylhydroquinone bis(4‐cyanatobenzoate) ( 3 ) were synthesized and cyclotrimerised to form s ‐triazine thermoset networks. All monomers have a nematic mesophase. Networks with frozen nematic textures were obtained from 2 and 3 while 1 underwent a transition from the nematic melt to a smectic thermoset. The curing reactions were monitored by infrared spectroscopy and calorimetry. The final conversion of the rigid monomers was approximately 95% from dynamic DSC experiments. The nematic‐isotropic transition and the glass transition temperature of 2 was measured as a function of conversion. The final glass transition temperature of the thermosets from the triaromatic dicyanates is 100°C and more below that of a diaromatic dicyanate, indicating that flexibility is increased with the number of ester groups between the branch points.