Table 1 Statistical testing results to examine equivalence between gamma irradiation vs. alternative technologies (e-beam and X-ray) in terms of their effects on polymer material properties.

From: Compatibility of ethylene vinyl acetate (EVA)/ethylene vinyl alcohol (EVOH)/EVA films with gamma, electron-beam, and X-ray irradiation

Material Properties

Metrics/Datasets

Industrial equivalency criteria for TOST

TOST conclusion based on industrial equivalency criteria

T-test conclusion (95% confidence level)

Coloration

Yellowness index, YI

N/A

-

ND

Total color difference, ΔE

<2

E

ND

Thermal

Melting temperature, Tm

<5 °C

E

CC

Degree of crystallinity, χc

N/A

-

ND

Glass transition temperature, Tg

<5 °C

E

ND

Mechanical

Elongation at break, EAB

<25% loss

E

ND

Ultimate tensile strength, UTS

<35% change

E

ND

Secant modulus, Es

N/A

-

ND

Tensile toughness, UT

N/A

-

ND

Spectro-scopic

UV (280 nm) absorption, Abs

N/A

-

CC

Carbonyl index, CI

N/A

-

ND

 

Surface free energy, SFE

N/A

-

ND

  1. The conclusions of two one-sided t-test (TOST) were based on industrial criteria, and the conclusions of t-test were based on 95% confidence level. “E”: can claim equivalence at all doses (30 kGy, 45 kGy, 60 kGy). “ND”: not different at any of the three dose levels. “CC”: cannot conclude on the equivalence with the current dataset. “N/A”: not available.
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