Page 281 - Academic Press Encyclopedia of Physical Science and Technology 3rd Polymer

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Encyclopedia of Physical Science and Technology En012c-604 July 26, 2001 16:2

790 Polymers, Thermally Stable

TABLE VI Chemical Structure of Commercial or Developmental Cyanate Esters Available in Monomer and/or Prepolymer Form
Melting
Homopolymer property
1994 point/
Polycyanate monomer Tradename/ cost viscosity T g % D k at G IC
◦
◦
structure/precursor supplier (£/kg) at 25 C ( C) H 2 O 1 MHz (Jm −2 )
◦
AroCy B/ 29 Crystal 79 C 289 2.5 2.91 140
CH 3
NCO OCN Ciba-Geigy
BT-2000/
CH 3
Bisphenol A Mitsubishi
GC
◦
H 3 C CH 3 AroCy M/ 44 Crystal 106 C 252 1.4 2.75 175
Ciba-Geigy
NCO CH 2 OCN
H 3 C CH 3
Tetramethylbisphenol F

◦
CF 3 AroCy F/ 99 Crystal 87 C 270 1.8 2.66 140
NCO OCN Ciba-Geigy
CF 3
Hexafluorobisphenol A

CH 3 AroCy L/ 66 Liquid 258 2.4 2.98 190
NCO OCN Ciba-Geigy 90–120 cP
H Semisolid
◦ a
Bisphenol E 29 C

CH 3 CH 3 RTX-366/ 68 Liquid 192 0.7 2.64 210
NCO OCN Ciba-Geigy 8000 cP
Semisolid
CH 3 CH 3
◦ a
68 C
Bisphenol M
OCN OCN OCN Primaset 68 Semisolid 270– 3.8 3.08 60
PT/Allied 250,000 cP b >350
Signal
CH 2 CH 2
REX-371/
n
Ciba-Geigy
Novolac resin

OCN OCN OCN XU-71787 — Semisolid 244 1.4 2.80 125
Dow 1000 cP c
Chemical

n
Dicyclopentadienyl bisphenol

Cured state properties: T g , glass transition temperature (DMA); % H 2 O, water absorption at saturation (100 C);D k , dielectric constant; G IC , fracture
◦
energy (double torsion method).
b
a Melting point of supercooled liquid; PT30; XU71787.02 (at 82 C).
c
◦
composites show exceptional impact resistance allied to a blending processess. Combining different CE monomers
dramatic reduction in delamination on impact. frequently improves not only their initial individual rhe-
An alternative approach to improving the properties of ological behavior but it can also result in improved
the base CE resin has involved a thermoset–thermoset properties for the cured resin. By using the correct