pultruded profile properties

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

Construction	Thickness mm	Flexural strength
		Orientation				Orientation
		0°	30°	60°	90°	0°	30°	60°	90°
		MPa	MPa	MPa	MPa	10³ psi	10³ psi	10³ psi	10³ psi
Standard profile	4	450	250	200	150	65	36	29	22
Unidirectional profile	4	900	200	50	50	130	29	7	7

Table 2 : VARIATION IN FLEXURAL MODULUS WITH ANGLE OF TEST

Construction	Thickness mm	Flexural strength
		Orientation				Orientation
		0°	30°	60°	90°	0°	30°	60°	90°
		MPa	MPa	MPa	MPa	10³ psi	10³ psi	10³ psi	10³ psi
Standard profile	4	21	12	10	8	3.0	1.7	1.5	1.2
Unidirectional profile	4	40	20	12	9	5.8	2.9	1.7	1.3

Table 3: VARIATION IN FLEXURAL PROPERTIES WITH THICKNESS

(0° AND 90° ORIENTATION)

Construction	Thickness of section MM	Flexural Strength				Flexural Modulus
		Orientation				Orientation
		0°	90°	0°	90°	0°	90°	0°	90°
		MPa	MPa	10³ psi	10³ psi	GPa	GPa	10³ psi	10³ psi
Standard profile	2.5	400	200	58	29	14	12	2.0	1.7
Standard profile	3.5	450	170	65	25	17	11	2.5	1.6
Standard profile	4.0	450	150	65	22	21	8	3.0	1.2
Standard profile	6.5	650	120	94	17	26	8	3.8	1.2
Unidirectional profile	-	900	50	130	7	40	9	5.8	1.3

COMPARISON OF PROPERTIES

	Units	Glass reinforced Thermoset resins				Thermoplastic resins		Metals
		Pultruded rod (Carbon)	Pultruded rod (Glass	Pultruded profile (Standard)	Sheet moulding compound	Nylon	PVC	Low Carbon Steel	Aluminium
Fibre content by volume	%	60	60	40	20	15	-	-	-
Specific gravity	gm/cm³	1.6	1.9	1.7	1.7	1.3	1.35	7.8	2.7
Flexural strength	MPa	1200	900	450	150	200	100	190	130
Flexural Modulus	GPa	125	44	17	10	10	3	210	70
Tensile strength	MPa	1050	800	400	70	90	100	125	165
Tensile Modulus	GPa	120	40	16	10	8	3	210	70
Compressive strength	MPa	800	450350	250	150	70	450	-
Thermal conductivity	W/M°C	N/A	0.3	0.3	0.3	0.25	0.1	45	150
Co-efficient of thermal expansion	°Cx10³	-0.7	6	9	20	30	70	13	23
Dielectric strength	KV/mm	N/A	12	12	12	16	1	N/A	N/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.

Material	Description	Density (gms/cm³)
Pultruded rod (Carbon fibre)	Unidirectional carbon fibre in epoxy resin	1.6
Pultruded rod (Glass)	Unidirectional glass in polyester resin matrix	1.9
Pultruded profile	Unidirectional roving core with bi-direction reinforcement and polyester resin matrix.Laminate thickness 3.5mm	1.7
Sheet moulding compound	A conventional"high glass" product with randomly orientated chopped glass	1.7
Nylon	Short fibre glass reinforced engineering thermoplastic	1.3
PVC	Unplasticised PVC	1.4

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