Glass and composites

glass-and-composites

10 materials across 7 types

About glass and composites

Glass and fibre composites (borosilicate glass, fused silica, E-glass, carbon-fibre composite, aramid, FR-4): density, stiffness, strength and temperature limits with sources.

Glasses are hard, stiff and brittle, and they soften over a range of temperatures instead of melting at one. Fibre composites put strong fibres in a resin so the part is light and stiff along the fibres. Each value here names its grade, form and condition.

At a glance

Highest density: E-glass fibre reaches 2.62 g/cm³. Lowest: SRC starts at 0.91 g/cm³. (9 of 10 grades have a sourced value.)
Highest young's modulus: CFRP reaches 230 GPa. Lowest: SRC starts at 0.55 GPa. (7 of 10 grades have a sourced value.)
Highest tensile strength: CFRP reaches 4,900 MPa. Lowest: SRC starts at 40 MPa. (5 of 10 grades have a sourced value.)

Ranges run across the conditions each source reports (temper, heat treatment, form), measured at room temperature where the source says so.

How they compare

The same measurements for every material in the collection. A range means the grade has values under several conditions; "at least" means the source gives a specified minimum. "no data" means no sourced value yet. For ranked tables, open a benchmark.

Glass and composites: how the grades compare
Material	Density	Young's modulus	Tensile strength	Thermal conductivity	Thermal expansion	Service temperature
Borosilicate glassoptical and laboratory glass	2.23 g/cm³	no data	no data	1.2 W/(m·K)	3.25 ppm/K	no data
Fused silica (SiO2 glass)optical window and cover glass	2.2 g/cm³	72.7 GPa	no data	1.3 to 1.4 W/(m·K)	0.55 ppm/K	1,080 °C
E-glass fibrereinforcement fibre	2.59 to 2.62 g/cm³	73 GPa	2,600 MPa	no data	no data	no data
CFRPstructural composite	1.3 to 1.8 g/cm³	11.7 to 230 GPa	64 to 4,900 MPa	no data	0.18 ppm/K	121 °C
FR-4rigid circuit-board substrate, woven glass cloth bonded with epoxy resin	no data	no data	no data	0.4 W/(m·K)	13 to 230 ppm/K	no data
Kevlar para-aramid fibrehigh-strength fibre	1.44 g/cm³	70.5 to 112 GPa	2,920 to 3,040 MPa	no data	no data	no data
Nomexmeta-aramid fibre and paper for spacesuit layers, thermal blankets and honeycomb	0.96 to 1.37 g/cm³	no data	340 to 2,960 MPa	0.14 W/(m·K)	18 ppm/K	204 °C
Soda-lime glasswindow and container glass	2.5 g/cm³	72 GPa	no data	0.94 W/(m·K)	9.5 ppm/K	110 to 150 °C
Aluminosilicate glassdisplay and cover glass	2.38 to 2.48 g/cm³	71.5 to 78 GPa	no data	1.09 W/(m·K)	31.7 to 81.4 x10^-7/C	no data
SRCstructural composite	0.91 to 1.44 g/cm³	0.55 to 112 GPa	40 to 3,000 MPa	no data	-4.9 ppm/K	82.2 to 177 °C

What these materials are made of

Composition by weight, as printed in the sources for each grade (the first constituents listed).

Composition of each grade
Material	Main constituents
Borosilicate glass	SiO2 80% · B2O3 13% · Na2O or K2O 4% · Al2O3 2%
Fused silica (SiO2 glass)	Si 46.7% · O 53.3%
Nomex	C 70.6% · H 4.2% · N 11.8% · O 13.4%
Soda-lime glass	SiO2 72.6% · Na2O 13.9% · CaO 8.4% · MgO 3.9% · Al2O3 1.1% · cullet 20%
Aluminosilicate glass	SiO2 67% · Na2O 25% · Al2O3 8%

Where they are used

Uses
Use	Grades
Reflecting telescope primary mirror	Borosilicate glass
Hot and cold mirrors and dichroic filters	Borosilicate glass
Telescope mirror substrates	Borosilicate glass
Optical window, lens and mirror substrate	Fused silica (SiO2 glass)
Solar-cell cover glass	Fused silica (SiO2 glass)
Crewed spacecraft windows (Space Shuttle forward windows)	Fused silica (SiO2 glass)
Boats and vehicle parts laminated with E-glass roving fabric	E-glass fibre
Containers and tanks laminated with E-glass roving fabric	E-glass fibre
Space launcher structures	CFRP
Primary and secondary aircraft structures	CFRP
Prototype optical bench of graphite-epoxy	CFRP
Printed circuit board substrate	FR-4
Computers and communication equipment	FR-4
Printed circuit boards in general	FR-4
Body armour and ballistic vests	Kevlar para-aramid fibre
Cut-resistant gloves and protective clothing	Kevlar para-aramid fibre

When each grade fits

Best use and weak spots of each grade
Material	Best for	Weakest at
Borosilicate glass	Laboratory glassware and optics that must survive temperature swings, where a low thermal expansion matters more than cost	Higher working temperature and processing cost than soda-lime glass; the expansion coefficient and hazard data could not be checked in this run
Fused silica (SiO2 glass)	Optics that must stay stable across temperature swings: very low thermal expansion and transparency from the ultraviolet to the near infrared	Brittleness, and a damaged pane can fail suddenly under tensile stress; the fetched sources give no outgassing numbers
E-glass fibre	General reinforcement of polyester, epoxy and vinylester laminates, such as boats, vehicle parts and containers, which are the end uses HP Textiles lists for its E-glass roving fabrics	Chemical resistance is not its strong point: HP Textiles lists C-glass, ECR-glass and boron-free Advantex as the corrosion-resistant types, and no E-glass corrosion value was read in this run
CFRP	Stiffness and strength per unit mass in structures: 164 GPa at 0 degrees in unidirectional IM7/8552 laminate	Strength across the fibres: 64 MPa at 90 degrees in unidirectional IM7/8552, and the epoxy limits service to about 121 C
FR-4	Standard printed circuit boards: 180 °C Tg and 60 min T260 for multilayer boards, as printed for Isola 370HR	Loss at high frequency and expansion above Tg: a Z-axis CTE of 230 ppm/°C above Tg, and a dissipation factor of 0.0210 at 2 GHz
Kevlar para-aramid fibre	Light, strong fibre for body armour, cut-resistant gear and ropes, where the fibre is shielded from sunlight	Ultraviolet light, which discolours it and cuts its mechanical strength; and low stiffness in compression
Nomex	Flame-resistant, high-temperature electrical and thermal insulation layers: continuous service to 220 °C and an LOI above 20.8 at 220 °C, as printed by DuPont	Atomic oxygen in low Earth orbit: an erosion yield of 1.41e-24 cm3/atom on MISSE 2 means surface loss in orbit. Strength also falls with UV exposure and with heat ageing: about 65 % of breaking strength is kept after 1000 h at 260 °C
Soda-lime glass	Windows and containers where low cost and wide availability matter more than thermal shock or alkali resistance	Resistance to sudden temperature changes (high thermal expansion) and to alkaline solutions (NGA: poor resistance to alkalis)
Aluminosilicate glass	Thin cover and display glass that is chemically strengthened, where hardness and a high softening point matter more than cost	Cost and processing: EAGLE XG has a working point of 1293 C, and strengthening needs a molten potassium salt bath (EAGLE XG data, Zeng et al. 2016)
SRC	Light, recyclable structures where one polymer family is wanted: UHMWPE SRC gives about 1.0 g/cm3 with 174.3 MPa along the fibres	Strength across the fibres: 7.7 MPa transverse against 174.3 MPa along them, and the polyolefin SRC softens near 135 C in its unfilled matrix