Kinetic Study of Photoinitiated Frontal Polymerization. Influence of UV Light Intensity Variations on the Conversion Profiles

Abstract

UV polymerizations in the presence of a photobleachable initiator are studied. The photoinitiator concentration vs time and the UV radiation intensity evolution within the sample are calculated according to rate equations. Polymerization and temperature profiles inside the sample are calculated assuming steady-state conditions. Thermal boundary conditions are chosen for orthopedic applications. The polymerization is then investigated under a range of photoinitiation conditions to access the ability to form thick materials. Theoretical results indicate that both cure depth and temperature rise can be controlled through the use of a photobleachable initiator and variation of the initiating UV radiation intensity during the polymerization.

Preparation and performance of thermosensitive poly(N‐isopropylacrylamide) hydrogels by frontal photopolymerization

“…An ideal reaction of FPP should satisfy three factors, namely light absorption, photobleaching and restricted mass transfer . Many fundamental studies on kinetics have provided guidance for the construction of an FPP system . Recently, FPP has provided a means for the fabrication of functional materials for microfluidic applications and patterning .…”

“…21 Many fundamental studies on kinetics have provided guidance for the construction of an FPP system. [22][23][24][25] Recently, FPP has provided a means for the fabrication of functional materials for microfluidic applications and patterning. 26,27 However, limited work has been attempted to explore the preparation of hydrogels by FPP.…”

Frontal free‐radical photopolymerization of thick samples: Applications to LED‐induced fiber‐reinforced polymers

“…Different authors have proposed some models to account for the frontal polymerization and it has been concluded that if the photoinitiator bleaches, the front propagates at a constant velocity in the sample . This has been used to generate gradient optical materials or microfluidic devices …”

Cure Depth of Photo‐Polymerized Gels

“…Zhang et al employed two‐exponent expressions for the monomer conversion. Hayki et al analyzed frontal photopolymerization considering auto‐acceleration parameters . However, while there have been many measurements of the monomer conversion as a function of time, regional molecular‐weight distributions have not been theoretically analyzed.…”

“…Hayki et al analyzed frontal photopolymerization considering auto-acceleration parameters. [19] However, while there have been many measurements of the monomer conversion as a function of time, regional molecular-weight distributions have not been theoretically analyzed. While the number-averaged molecular weight as the spatially homogenous sample is determined by GPC analysis, etc., determination of practical cure depths requires local distribution of the molecular weight.…”