Tech Library

Understanding material property data

A structured reference to commonly used material properties and terminology. Hover over any listed term to view its definition and better understand how it is used in material evaluation and selection.

Mechanical Properties

Tensile modulus
Tensile strength
Strain at break
Flexural modulus
Flexural strength
Creep modulus
Charpy impact
Izod notched impact
Rockwell hardness
Tensile stress at yield
Elongation at yield
Poisson's ratio
Tear strength
Compressive strength
Shear strength
Tensile impact strength
Unnotched Charpy impact
Fatigue strength
Fracture toughness
Shore hardness (A/D)
Ball indentation hardness

Processing Parameters

Drying
Melt temperature
Mold temperature
Hold pressure
Ejection temperature
Injection pressure
Back pressure
Residence time
Cooling / cycle time
Regrind ratio
Dew point (drying)
Nozzle temperature
Compression ratio

Rheological Properties

Viscosity number
Molding shrinkage
Postmolding shrinkage
Melt flow rate (MFR)
Melt volume rate (MVR)
Intrinsic viscosity (IV)
Shear viscosity
Spiral flow length
Melt strength

Electrical Properties

Dielectric constant
Dissipation factor
Volume resistivity
Dielectric strength
CTI
Surface resistivity
Arc resistance
Insulation resistance
Tracking resistance
Electrostatic dissipation (ESD)

Thermal Properties

Melting point (Tm)
Glass transition (Tg)
Heat deflection (HDT)
Vicat softening
CLTE
Thermal conductivity
Specific heat
RTI
Crystallization temperature (Tc)
Continuous use temperature (CUT)
Ball pressure temperature
Thermal diffusivity
Decomposition temperature
Brittleness temperature
Heat-aging resistance

Chemical & Environmental Performance

Chemical resistance
VOC emission
Odor & fogging
Hydrolysis resistance
UV / weathering resistance
Environmental stress-crack resistance (ESCR)
Gas / moisture permeability
Water-vapor transmission rate (WVTR)
Oxygen transmission rate (OTR)

Flammability Characteristics

UL94 rating
Oxygen index (LOI)
Glow wire (GWFI / GWIT)
FMVSS 302
UL94 5VA / 5VB
Smoke density
Heat release rate
Hot-wire ignition (HWI)
High-current arc ignition (HAI)
Needle-flame test

Physical Properties

Water absorption
Density
Melt density
Specific gravity
Bulk density
Equilibrium moisture
Glass-fiber / filler content
Ash content