ASTM · POLYMER STANDARDS
ASTM and ISO standards for plastics testing
An at-a-glance overview of key test and material specification standards, as a starting point for thermoplastics and thermosets.
THERMOPLASTICS
Thermoplastics
- ASTM D638
Tensile properties of plastics
Tensile strength, modulus and elongation at break on dumbbell specimens; the basis for comparing grades and for quality control.
ISO 527-1 / ISO 527-2 - ASTM D790
Flexural properties of plastics
Flexural modulus and strength under three-point bending; a measure of how well a part resists bending.
ISO 178 - ASTM D256
Izod impact resistance
Energy to break a notched specimen with a pendulum; used to compare toughness and notch sensitivity.
ISO 180 - ASTM D1238
Melt flow rate of thermoplastics
Mass of melt extruded through a standard die at a set temperature and load (MFR); an index of processability and batch consistency.
ISO 1133-1 - ASTM D648
Deflection temperature under flexural load
Temperature at which a specimen under a set flexural stress reaches a specified deflection (HDT); used to assess performance at elevated temperature.
ISO 75-1 / ISO 75-2 - ASTM D1525
Vicat softening temperature
Temperature at which a standard needle penetrates the specimen by 1 mm under a set load; an index of thermal softening.
ISO 306 - ASTM D3418
Thermal transitions, melting and crystallization by DSC
Melting, crystallization and glass transition temperatures and their enthalpies by DSC; used for material identification and crystallinity.
ISO 11357-2 / ISO 11357-3 - ASTM D792
Density and specific gravity of plastics
Density and specific gravity by water displacement; used to check composition, filler content and material identity.
ISO 1183-1 - ASTM D570
Water absorption of plastics
Percentage weight gain after immersion in water; important for dimensional stability and properties of polyamides and composites.
ISO 62
THERMOSETS
Thermosets
- ASTM D638
Tensile properties of cured plastics
Tensile properties of cured resins and composites; used to compare formulations and degree of cure.
ISO 527-2 - ASTM D790
Flexural properties of reinforced and unreinforced plastics
Flexural modulus and strength of laminates and molded parts; one of the most common quality-control tests for thermosets.
ISO 178 / ISO 14125 - ASTM D695
Compressive properties of rigid plastics
Compressive modulus and strength of rigid plastics; for parts under compressive load.
ISO 604 - ASTM D2583
Barcol hardness of rigid plastics
Surface hardness with a Barcol impressor; a quick check of full cure on the part.
No direct ISO equivalent · EN 59 - ASTM D5083
Tensile properties of reinforced thermosets
Tensile properties of reinforced thermosets using straight-sided rectangular specimens.
Comparable to ISO 527-4 - ASTM D3795
Thermal flow and cure behavior by torque rheometer
Torque and time to melt, flow and cure of thermosetting compounds in a torque rheometer; used to set the processing window.
No direct ISO equivalent - ASTM D3123
Spiral flow of low-pressure thermoset molding compounds
Flow length in a spiral mold; a measure of the flow of low-pressure molding compounds such as electronic encapsulants.
No direct ISO equivalent - ASTM D1763
Specifications for epoxy resins
Specification and classification of epoxy resins, such as epoxy equivalent weight and viscosity; the basis for purchasing and incoming inspection.
Related tests: ISO 3001 - ASTM D5948
Specifications for thermosetting molding compounds
Specification and classification of thermosetting molding compounds by resin type, filler and properties.
Comparable to ISO 14526 to ISO 14530
Choosing the right standard for the material
Some methods, such as tensile and flexural tests, apply to both groups; the final choice depends on the scope of the standard, the material type and the specimen form. This list gives indicative titles only; check the edition, current status and test requirements in the official source before use.