Ion beam assisted thermal depolymerisation of poly (methyl methacrylate) (PMMA) thin films, 1 mu m thick, has been studied in the temperature range RT -400 degrees C using a 300 keV He+ beam at very low fluence (<10(12) ions cm(-2)). The experiments have been performed using an in situ mass spectrometer in a 10(-7) torr vacuum chamber. A relevant methyl methacrylate monomer (MMA) evolution (mass signal m/t = 100) at temperature (150 degrees C) well below the polymer degradation temperature (360 degrees C) has been detected during irradiation. These results have been compared with gas evolution during room temperature ion irradiation where volatile products different from monomer are known to be produced due to chain scission events. The low-temperature depolymerisation induced by ion irradiation performed on PMMA at temperature higher than T-g (105 degrees C) is promoted by the presence of beam-induced reactive species acting as initiators. (C) 1998 Published by Elsevier Science B.V. All rights reserved.
Ion beam assisted unzipping of PMMA
FRAGALA', Maria Elena;COMPAGNINI, Giuseppe Romano;PUGLISI, Orazio Gaetano
1998-01-01
Abstract
Ion beam assisted thermal depolymerisation of poly (methyl methacrylate) (PMMA) thin films, 1 mu m thick, has been studied in the temperature range RT -400 degrees C using a 300 keV He+ beam at very low fluence (<10(12) ions cm(-2)). The experiments have been performed using an in situ mass spectrometer in a 10(-7) torr vacuum chamber. A relevant methyl methacrylate monomer (MMA) evolution (mass signal m/t = 100) at temperature (150 degrees C) well below the polymer degradation temperature (360 degrees C) has been detected during irradiation. These results have been compared with gas evolution during room temperature ion irradiation where volatile products different from monomer are known to be produced due to chain scission events. The low-temperature depolymerisation induced by ion irradiation performed on PMMA at temperature higher than T-g (105 degrees C) is promoted by the presence of beam-induced reactive species acting as initiators. (C) 1998 Published by Elsevier Science B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
