Correlation between Critical Energy, Penetration Depth, and Photopolymerization Kinetics in Aluminum–Phosphate–Silicate Hybrid Materials for Vat Photopolymerization

Abstract

The photopolymerization of aluminum–phosphate–silicate resins obtained from the hybrid sol–gel route for Vat photopolymerization (VPP) process was investigated. The printing parameters derived from Jacob’s work curve model, critical energy (E c) and penetration depth (D p), were determined as a function of laser power and MPTMS (silicate) concentration for materials with stoichiometry Si(x)-(Al + P)(1–x), 0 ≤ x ≤ 0.7. The kinetics of photopolymerization was further explored using steady- and unsteady-state photo-DSC experiments. The oxygen inhibition and primary termination had similar contributions to the polymerization process for all compositions, while the propagation and bimolecular termination constants increased with MPTMS concentration. These experimental results were used to test the validity of the E c ∝ k t 1/2/k p and D p ∝ ϵ relationship derived from a photochemical model for VPP assuming steady-state kinetics. Both E c ∝ (k t 1/2/k p) and D p ∝ ϵ may be used to predict critical energy and penetration values for an arbitrary resin without calculating its work curve function, according to our study.

Internal Microdomain Regulatory Based on Upconversion Particles for Controllable Near-Infrared Photopolymerization Kinetics and Material Properties

“…Photopolymerizations have significantly advanced the polymer field in coatings, photoresists, adhesives, and 3D printing by providing extra spatiotemporal control and efficient fabrication capability under mild circumstances. − Photopolymerization processes integrated with regulation strategies, including the photoactivity (photoinitiators or resins) and external irradiation intensity, may render fresh performances and functions to the photopolymers. − However, such polymers, which commonly require the screening of specific oligomer precursors, are challenging to reconcile the various material properties from the photopolymerization kinetics regulatory through light intensity alone, instead of modifying the host formulation structures. − In parallel, conventional low-penetration UV light-induced photopolymerization is difficult to apply to bulk materials and complex substrates, further limiting the regulatory dimensionality of photopolymerization techniques. , …”