Poly(methyl methacrylate) (PMMA) was ␥-irradiated (5-20 kGy) by a 137 Cs source at room temperature in air. The changes in the molecular structure attributed to ␥-irradiation were studied by mechanical testing (flexure and hardness), size-exclusion chromatography, differential scanning calorimetry, thermal gravimetric analysis, and both Fourier transform infrared and solution 13 C-NMR spectroscopy. Scanning electron microscopy was used to investigate the influence of the dose of ␥ rays on the fracture behavior of PMMA. The experimental results confirm that the PMMA degradation process involves chain scission. It was also observed that PMMA presents a brittle fracture mechanism and modifications in the color, becoming yellowish. The mechanical property curves show a similar pattern when the ␥-radiation dose increases.

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