The effects of radiation on material properties of plastics

Radiation induces chemical reactions in the materials exposed. Accordingly, it is of critical importance to understand the changes which might take place in the materials used in the product or the protective packaging irradiated. Based on the chemical nature some materials are resistant to radiation. Others may show changes ranging from only slight discoloration up to changes of the internal structure, having a negative impact on their function.

Referring to changes of mechanical characteristics:
starstarstar highly recommended – starstar recommended – star recommended with limitation – star_empty not recommended

Thermoplastics

PolymerResistanceRemark
Aromatic polyamide-imidesstarstarstarHigh strength properties, resistant due to ring-shaped molecular structure.
Polysulphone (PSU)starstarstarInherent yellowish-brown colour. Highly resistant
Polyimide (PI)starstarstarHighly resistant thanks to ring-shaped molecular structure.
Polystyrene (PS)starstarVery resistant due to its ring-shaped molecular structure. Discolouration may occur in transparent grades. Impact-modified grades are less resistant.
Acrylonitrile/butadiene/styrene (ABS)starstarThe butadiene component begins to disintegrate upwards of approx. 100 kGy. Avoid high doses with impact-modified grades.
Polycarbonate (PC)starstarDiscolouration possible, special grades available. Discolouration may disappear after tempering.
Aromatic polyesters (PET/PETG/PBT)starstarVery stable, retains its excellent transparency. Must be pre-dried prior to processing.
Styrene acryolnitrile copolymers (SAN)starstarYellowing from about 40 kGy possible.
Polyvinylidene fluoride (PVDF)starstar
Ethylene tetrafluoroethylene (ETFE)starstar
Polyethylene (LDPE/HDPE/LLDPE/MDPE)
and copolymers
starstarCrosslinked for improved strength properties, hence reduced elongation at break. LDPE is the most resistant.
Cyclic olefin copolymer (COC/COP)starstarRetains its high transparency and impact resistance.
Polymethyl methacrylate (PMMA)starDiscolouration at around 20-40 kGy.
Cellulose acetate butyrate (CAB)starRetains its high transparency and impact resistance.
Polyamides (PA) aliphatic and amorphous typesstarDiscolouration possible. Avoid thin films and fibres. PA 11 and PA 12 give the best performance.
Polyvinyl chloride (PVC)starStandard grades undergo changes, hydrochloric acid may be released. Strongly dependent on the formulation. Special grades are available for higher radiation resistance. Colour changes are possible.
Polyvinylidene chloride (PVDC)starYellowish discolouration, separation of hydrochloric acid.
Fluorinated ethylene/propylene (FEP)star
Polypropylene (PP) copolymerstarMore stable than PP homopolymers. Specially stabilized grades are recommended.
Polypropylene (PP) homopolymerstarDecline of mechanical properties with increase of radiation dose when stored. Only use stabilized types.
Polyacetal (POM)star_emptyNot recommended, very strong embrittlement.
Polytetrafluoroethylene (PTFE)star_emptyDisintegrates very rapidly, releases corrosive gases. Avoid use.

Thermosets

PolymerResistanceRemark
Phenol/formaldehyde (PF moulding compounds) Urea/formaldehyde (UF moulding compounds)
Melamine/formaldehyde (MF moulding compounds)
Unsaturated polyester resins (UP resins)
starstarstarAll thermosets have very high resistance. Some of them may release gaseous products.

Elastomers

PolymerResistanceRemark
Nitrile rubberstarstar
Ethylene propylene diene rubber (EPDM)
Polyurethane rubber
TPU/TPE
starCrosslinkable grades are available.
Resistance to radiation largely depending on formulation
Natural rubberstarProperty changes are very strongly dependent on wall thickness.
SiliconesstarIncrease in shore hardness is possible.
Fluororubbersstar
Butyl rubberstarProperty changes occur already at low doses.

Please note: These tables can give only an indication. Behaviour against radiation may largely vary depending on molecular structure and additives used. In cases of doubt, please consult with our specialists.

Print