GFRP (Isotropic)

The material. Composites are one of the great material developments of the 20th century. Those with the highest stiffness and strength are made of continuous fibers (glass, carbon, or Kevlar, an aramid) embedded in a ther­mosetting resin (polyester or epoxy). The fibers carry the mechanical loads, whereas the matrix material transmits loads to the fibers and provides duc­tility and toughness as well as protecting the fibers from damage caused by handling or the environment. It is the matrix material that limits the service temperature and processing conditions. Polyester-glass composites (GFRPs) are the cheapest and by far the most widely used. A recent innova­tion is the use of thermoplastics at the matrix material, either in the form of a coweave of cheap polypropylene and glass fibers that is thermoformed, melting the PP, or as expensive high-temperature thermoplastic resins such as PEEK that allow composites with higher temperature and impact resistance. High-performance GFRP uses continuous fibers. Those with chopped glass fibers are cheaper and are used in far larger quantities. GFRP products range from tiny electronic circuit boards to large boat hulls, body and interior panels of cars, household appliances, furniture, and fittings.

Composition

Epoxy + continuous E-glass fiber reinforcement (0, н— 45, 90), quasi­isotropic layup.

General properties

Density

1750

– 1970

kg/m3

Price

*19.44

– 21.39

USD/kg

Mechanical properties

Young’s modulus

*15

– 28

GPa

Yield strength (elastic limit)

*110

– 192

MPa

Tensile strength

*138

– 241

MPa

Elongation

*0.85

– 0.95

%

Hardness—Vickers

*10.8

– 21.5

HV

Fatigue strength at 107 cycles

*55

– 96

MPa

Fracture toughness

*7

– 23

MPa. m1/2

Thermal properties

Maximum service temperature Thermal conductor or insulator?

*413 – 493 Poor insulator

°C

Thermal conductivity

*0.4

– 0.55

W/m. K

Specific heat capacity

*1000

– 1200

J/kg. K

Thermal expansion coefficient

*8.6

– 32.9

p, strain/°C

GFRP body shell by MAS Design, Windsor, UK.

Electrical properties

Electrical conductor or insulator? Good insulator

Electrical resistivity

*2.4 X 1021

– 1.91 X 1022

p, ohm.

Dielectric constant

4.86

– 5.17

Dissipation factor

0.004

– 0.009

Dielectric strength

11.8

– 19.7 106

V/m

Ecoproperties

Embodied energy, primary production

*107

– 118

MJ/kg

CO2 footprint, primary production

*7.47

– 8.26

kg/kg

Water usage

*105

– 309

l/kg

Material processing: energy

Simple composite molding energy

*11.3

– 12.4

MJ/kg

Simple composite molding CO2

*0.90

– 0.99

kg/kg

Advanced composite molding energy

*18.4

– 20.3

MJ/kg

Advanced composite molding CO2

*1.48

– 1.63

kg/kg

Material recycling: energy, CO2

and recycle fraction

Recycle fraction in current supply

0.5

– 1

%

Typical uses. Sports equipment such as skis, racquets, skate boards and golf club shafts, ship and boat hulls; body shells; automobile components; cladding and fittings in construction; chemical plant.