Alex Stiles - Academia.edu (original) (raw)

Uploads

Papers by Alex Stiles

Research paper thumbnail of Photopolymer formulation towards large scale additive manufacturing of autoclave capable tooling

Additive Manufacturing, 2021

Research paper thumbnail of Photoinitiator Selection and Concentration in Photopolymer Formulations towards Large-Format Additive Manufacturing

Polymers

Photopolymers are an attractive option for large-format additive manufacturing (LFAM), because th... more Photopolymers are an attractive option for large-format additive manufacturing (LFAM), because they can be formulated from structural thermosets and cure rapidly in ambient conditions under low-energy ultraviolet light-emitting diode (UV LED) lamps. Photopolymer cure is strongly influenced by the depth penetration of UV light, which can be limited in the 2–4 mm layer thicknesses typical of LFAM. Photoinitiator (PI) systems that exhibit photobleaching have proven useful in thick-section cure applications, because they generate a photoinitiation wavefront, but this effect is time-dependent. This study investigates the light transmission and through-thickness cure behavior in (meth)acrylate photopolymer formulations with the photobleaching initiator bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (BAPO). Utilizing an optical model developed by Kenning et al., lower concentrations (0.1 wt% to 0.5 wt%) of BAPO were predicted to yield rapid onset of photoinitiation. In situ cure measure...

Research paper thumbnail of Photopolymer formulation towards large scale additive manufacturing of autoclave capable tooling

Additive Manufacturing, 2021

Research paper thumbnail of Photoinitiator Selection and Concentration in Photopolymer Formulations towards Large-Format Additive Manufacturing

Polymers

Photopolymers are an attractive option for large-format additive manufacturing (LFAM), because th... more Photopolymers are an attractive option for large-format additive manufacturing (LFAM), because they can be formulated from structural thermosets and cure rapidly in ambient conditions under low-energy ultraviolet light-emitting diode (UV LED) lamps. Photopolymer cure is strongly influenced by the depth penetration of UV light, which can be limited in the 2–4 mm layer thicknesses typical of LFAM. Photoinitiator (PI) systems that exhibit photobleaching have proven useful in thick-section cure applications, because they generate a photoinitiation wavefront, but this effect is time-dependent. This study investigates the light transmission and through-thickness cure behavior in (meth)acrylate photopolymer formulations with the photobleaching initiator bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (BAPO). Utilizing an optical model developed by Kenning et al., lower concentrations (0.1 wt% to 0.5 wt%) of BAPO were predicted to yield rapid onset of photoinitiation. In situ cure measure...

Log In