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For most photoinduced free radical based polymerizations, the uniformity of double bond conversion as a function of coating thickness as well as a high total degree of conversion 1, 2] are crucial for the performance characteristics of the photopolymerized coating. In this study, the influence of irradiance (lo) and photoinitiator concentration Ph!]) was evaluated with respect to the depth profile of conversion (Cd). The investigation was performed at a constant absorbed light intensity (Ia). This was accomplished by an eight fold variation of the irradiance and photoinitiator concentration simply by using the direct proportionality relation 'a = Const. • PhIJ. The purpose of the study was simply to define conditions for optimization and predictions for control of Cd. The photopolymerizations were performed under laminated conditions at various film thickness. Degrees of conversion were obtained by the use of FTIR. The apparent technical benefits are therefore quite obvious, such as possibility of controlling Cd. As a practical result a dramatic reduction of Ph!] and higher degrees of conversion at low Ph!] and high can be achieved.
