PE-X (polyethylene cross-linked, wire and cable grade)

Designation

Crosslinked polyethylene / XLPE / PEX (Wire and Cable Grade)

Tradenames

Borealis, Borlink, Dow Electrical Telecommunications, Endurance, Getilan, Hyundai, Icorene, Kafrit, LNP Lubricomp, LNP Stat-Kon, Polidan, Polylink, Polylink Power, Schulink, Superclean, Supercopo, Supercure, Supersmooth, Supertr, Syncure, Visico

Typical uses

Cable covering, shrink-wrap film, heat-shrinkable tubing, pipe for domestic heating systems, rotationally molded tanks.

Compositional summary

(CH2-CH2)n with a high degree of cross-linking by one of four methods. (A) peroxide, C-C cross-links; (B) silane, C-Si-O-Si-C cross-links; (C) electron beam processing; (D) azo (nitrogen) cross-links.

Material family	Plastic (thermoplastic, semi-crystalline)
Base material	PE-X (Polyethylene, crosslinked)
Polymer code	PE-X

Composition detail

Polymer

100

Physical properties

Density

0.92

–

1.24

g/cm³

Mechanical properties

Young’s modulus	0.537	–	0.564	GPa
Specific stiffness	0.443	–	0.599	MN.m/kg
Yield strength (elastic limit)	8.27	–	13.8	MPa
Tensile strength	10.3	–	21.4	MPa
Specific strength	7.5	–	13.3	kN.m/kg
Elongation	180	–	600	% strain
Compressive modulus	0.537	–	0.564	GPa
Compressive strength	9.92	–	16.6	MPa
Flexural modulus	0.537	–	0.564	GPa
Flexural strength (modulus of rupture)	14.4	–	30	MPa
Shear modulus	0.188	–	0.197	GPa
Bulk modulus	1.32	–	1.38	GPa
Poisson’s ratio	0.431	–	0.433
Shape factor	5.4
Hardness – Vickers	3	–	4	HV
Elastic stored energy (springs)	65.5	–	164	kJ/m³
Fatigue strength at 10^7 cycles	4.12	–	8.56	MPa

Impact & fracture properties

Fracture toughness	0.404	–	0.485	MPa.m^0.5
Toughness (G)	0.298	–	0.424	kJ/m²
Impact strength, notched 23 °C	1.4	–	2.2	kJ/m²

Thermal properties

Melting point	102	–	177	°C
Glass temperature	-125	–	-90	°C
Heat deflection temperature 0.45MPa	63	–	103	°C
Heat deflection temperature 1.8MPa	38	–	78	°C
Maximum service temperature	90	–	110	°C
Minimum service temperature	-81	–	-71	°C
Thermal conductivity	0.175	–	0.182	W/m.°C
Specific heat capacity	1.6e3	–	1.67e3	J/kg.°C
Thermal expansion coefficient	176	–	184	µstrain/°C
Thermal shock resistance	83.4	–	140	°C
Thermal distortion resistance	9.66e-4	–	0.00102	MW/m

Electrical properties

Electrical resistivity	2.37e23	–	2.13e24	µohm.cm
Electrical conductivity	8.08e-23	–	7.27e-22	%IACS
Dielectric constant (relative permittivity)	2	–	2.2
Dissipation factor (dielectric loss tangent)	1e-4	–	7e-4
Dielectric strength (dielectric breakdown)	24.4	–	29.9	MV/m

Magnetic properties

Magnetic type

Non-magnetic

Optical, aesthetic and acoustic properties

Transparency	Translucent
Acoustic velocity	664	–	776	m/s
Mechanical loss coefficient (tan delta)	0.0709	–	0.0745

Absorption & permeability

Water absorption @ 24 hrs

0.01

–

0.06

Processing properties

Polymer injection molding	Limited use
Polymer extrusion	Excellent
Polymer thermoforming	Unsuitable
Linear mold shrinkage	2	–	5	%
Melt temperature	116	–	204	°C
Mold temperature	30	–	50	°C
Molding pressure range	70	–	140	MPa

Durability

Water (fresh)	Acceptable
Water (salt)	Acceptable
Weak acids	Acceptable
Strong acids	Acceptable
Weak alkalis	Acceptable
Strong alkalis	Acceptable
Organic solvents	Limited use
Oxidation at 500C	Unacceptable
UV radiation (sunlight)	Fair
Flammability	Highly flammable