One of the effects induced by ion beam bombardment of molecular solids is the aggregation between adjacent molecules. It is due to the formation of new covalent bonds (cross linking) and is generally accompanied by chain scission and H-2 emission. With increasing fluence, for polymers with a cross linking yield higher than the scission yield, the final result is the formation of a gel. In this paper we analyse the beam induced gel formation in terms of two models: a statistical model of aggregation and a Monte Carlo simulation of random percolation. We show that ''pseudo-gelled'' material can be formed in the isolated track but that this cannot explain the formation of a gel. Only by taking into account the possibility of multiple track overlap the gel formation can be explained.
INTRATRACK EFFECTS AND TRACK OVERLAP IN-BEAM INDUCED AGGREGATION OF POLYMERS
LICCIARDELLO, Antonino
1994-01-01
Abstract
One of the effects induced by ion beam bombardment of molecular solids is the aggregation between adjacent molecules. It is due to the formation of new covalent bonds (cross linking) and is generally accompanied by chain scission and H-2 emission. With increasing fluence, for polymers with a cross linking yield higher than the scission yield, the final result is the formation of a gel. In this paper we analyse the beam induced gel formation in terms of two models: a statistical model of aggregation and a Monte Carlo simulation of random percolation. We show that ''pseudo-gelled'' material can be formed in the isolated track but that this cannot explain the formation of a gel. Only by taking into account the possibility of multiple track overlap the gel formation can be explained.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
