Carbon and composites · Workhorse

CFRP with cyanate ester resins

CFRPvalues describe: cyanate ester CFRP

Space test

Why it wins

Optical benches and metering structures that fly: carbon fiber stiffness with resins chosen for microcracking resistance and low moisture outgassing, then baked and bagged before TVAC.

Why not the alternative

Epoxy CFRP drinks moisture and exhales it on orbit, distorting the very geometry it was meant to hold.

Watch out

Every cut edge is an outgassing surface: seal or bake accordingly.

Properties

The values below are candidate: compiled from the sources named, not yet individually validated. Provisional provenance: ECSS space product assurance standards; NASA outgassing database.

Wet cleaning

Recipe	solvent wipe only, then long vacuum bake at 120–150 °C to drive off absorbed water
Forbidden	immersion: the laminate absorbs and holds water for weeks
Limit	TML and CVCM to the space standard, measured not assumed

Vacuum and outgassing

Outgassing, unbaked (10 h)	5e-7 mbar·L/s/cm²
Outgassing, baked	1e-9 mbar·L/s/cm²
Vapour pressure	resin volatiles; cyanate ester chosen for low CVCM

Temperature

Bake, assembled	150 °C
Vacuum degas	200 °C
Metallurgical limit	Tg 250 °C cyanate ester; epoxy far lower

Thermal

CTE	-0.5 to 2 along fibre ppm/K
Thermal conductivity	5–50 along fibre W/m·K
Specific heat	900 J/kg·K
Emissivity	0.9
Melting / softening	no melt

Mechanical

Strength	600–1500 tens along fibre MPa
Elongation	1–2 %
Young's modulus	70–200 GPa
Density	1.6 g/cm3

Electrical and magnetic

Relative permeability	1.0
Resistivity	conductive along fibre

Engineering

Corrosion	good
Joining	bonded or bolted
Process notes	moisture uptake dominates the pump-down
Availability and cost	aerospace supply chain

Grades

RS-3 class cyanate ester prepreg	dimensionally stable optical structures
EX-1515 class	low moisture uptake laminates

Sources · 2

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