Branching at High Frequency Pulsed Laser Polymerizations of Acrylate Monomers

An experiment was conducted to demonstrate branching at high frequency pulsed laser polymerizations (PLP) of acrylate monomers. In the Monte Carlo simulation, 10 000 radicals with a concentration of 1-10-5 mol/L were considered to be produced by each laser pulse. The events that each of these radicals undergo were selected based on the probability of the corresponding reaction mechanism, provided that the time needed to undergo the chosen reaction did not exceed the life expectancy of the radical. PLP experiments for n-BA under bulk conditions were simulated at temperatures from -40 to 140°C at laser pulse frequencies in the range 10-2000 Hz. It can be seen that branching density increased with temperature, and for a given temperature, the increase in laser pulse frequency considerably reduced the branching density. On the other hand, the characteristic times for backbiting were longer than the time between laser pulses at 500 and 1000 Hz, and therefore backbiting was less probable.