Pultruded Profile Properties

Fibre reinforced plastic profiles

The Pultrusion process is a method of continuously manufacturing Fibre Reinforced Plastic profiles of high strength and stiffness. Many different reinforcements and matrix systems can be used, but standard constructions usually consist of glass and polyester resins.

Flexural Properties

The values quoted below have been determined on test coupons cut from profiles produced using glass as reinforcement and an unsaturated polyester resin cured at elevated temperature as the matrix system.

The test method used was a 3-point flexural bend test using a 16 to 1 span to depth ratio corresponding to BS2782-304 and ATSM D-790.

Pultruded profiles normally exhibit a high degree of anisotropy so that the orientation of the test samples is very important.  The angle formed between the test piece geometry and the unidirectional fibre component is referred as the sample orientation.

Standard construction is either all-unidirectional E glass roving at 58% by volume glass content or a unidirectional E glass-roving core with 450 gsm Continuous Filament Mat (CFM) on each face giving a total of 38% by volume glass content.

Table 1 : Variation in flexural strength with angle of test

Flexural strength
MPaMPaMPaMPa10  psi10  psi10  psi10  psi
Standard profile445025020015065362922
Unidirectional profile490020050501302977

Table 2 : Variation in flexural modulus with angle of test

Flexural strength
MPaMPaMPaMPa10  psi10  psi10  psi10  psi
Standard profile421121083.
Unidirectional profile440201295.

Table 3: Variation in flexural properties with thickness

Flexural strength
MPaMPa10  psi10  psiGPaGPa10  psi10  psi
Standard profile3.5400200582914122.01.7
Standard profile3.5450170652517112.51.6
Standard profile4.045015065222183.01.2
Standard profile6.565012094172683.81.2
Unidirectional profile9005013074095.81.3

Comparison of Properties

TESTUnitsGlass reinforced Thermoset resinsThermoplastic resinsMetals
Pultruded rod (Carbon)Pultruded rod (GlassPultruded profile (Standard)Sheet moulding compoundNylonPVCLow Carbon SteelAluminium
Fibre content by volume%6060402015
Specific gravitygm/cm1.
Flexural strengthMPa1200900450150200100190130
Flexural ModulusGPa12544171010321070
Tensile strengthMPa10508004007090100125165
Tensile ModulusGPa1204016108321070
Compressive strengthMPa80045035025015070450
Thermal conductivityW/M CN/A0.
Co-efficient of thermal expansion Cx10-0.7692030701323
Dielectric strengthKV/mmN/A121212161N/AN/A

Specific property comparison

The specific property is defined as the property divided by the density.  It gives a good indication of the frequency of supports required for a suspended structure or the overall weight of a structure to meet defined criteria.

MaterialDescriptionDensity (gms/cm)
Pultruded rod (Carbon fibre)Unidirectional carbon fibre in epoxy resin1.6
Pultruded rod (Glass)Unidirectional glass in polyester resin matrix1.9
Pultruded profileUnidirectional roving core with bi-direction reinforcement and polyester resin matrix.Laminate thickness 3.5mm1.7
Sheet moulding compoundA conventional”high glass” product with randomly orientated chopped glass1.7
NylonShort fibre glass reinforced engineering thermoplastic1.3
PVCUnplasticised PVC1.4

pdf Click Here to download a Pultrex document (PDF) illustrating Standard tolerances for Pultruded Profiles