Development of New Photoinitiating Systems for Depth Curing of Thick Materials

Abstract

The production of thick materials by photopolymerization, such as those required for fiber-reinforced polymer is still rather scarce today. This fact is mainly attributed to the low penetration depth of the light into the composites. In this paper, it will be first shown that glass fiber composites can be formed easily by using a suitable photoinitiating system. Secondly, attention will be paid on carbon fiber composite where a dual-cure initiating system based on both a photoinitiator and a thermal initiating system is able to produce polymer part of few millimeters in a relatively short time scale.

Free radical photopolymerization process for fiber‐reinforced polymer: Effect on the mechanical properties

“…However, the presence of a conversion gradient was identified between the up and down faces (85% against 76%). It was attributed to the gradient of irradiation intensity in depth as already reported in the literature . This gradient leads to different Barcol hardness and is expected to also affect their mechanical properties …”

“…It was attributed to the gradient of irradiation intensity in depth as already reported in the literature. [18][19][20][21] This gradient leads to different Barcol hardness and is expected to also affect their mechanical properties. 22 With samples P1 and P2, the fabrication of a thermally cured composite sample with or without post-curing step requires a time of 3 or 15 hours for P1 and P2, respectively.…”

A new safranin based three-component photoinitiating system for high resolution and low shrinkage printed parts via digital light processing

“…In recent years, visible light initiating systems have been highly regarded in order to solve some UV radiation issues such as high heat build-up, safety, and curing of thick samples. 33,34 However, there is very limited photoinitiator leading to photodissociation in the visible region. 35 Therefore, using two/threecomponent photoinitiating systems (PIS), consisting of a photosensitizer and one or two coinitiator(s) have been pointed out.…”

The use of upconversion microparticles as a novel internal radiation source for fabrication of composite materials

“…Various methods have been suggested for enhancing cure depth and DC in composite photopolymerization including. The effect of photoinitiating system type , application of bleachable photoinitiators , matching the absorption spectrum of photoinitiator with emission spectrum of light source units and the effect of photoinitiator concentration . In addition, the influence of nanoparticles, pigments, and fillers as well as their concentrations on the conversion gradient and curing behavior has been studied .…”