Morphology Control in a Dual-Cure System for Potential Applications in Additive Manufacturing

Abstract

The polymerisation, morphology and mechanical properties of a two-component in-situ reacting system consisting of a rubbery dimethacrylate and a rigid epoxy polymer were investigated. The methacrylate component of the mixture was photocured using UV light exposure and, in a second curing process, the mixture was thermally postcured. The polymers formed a partially miscible system with two glass transition temperature (Tg) peaks measured using dynamic mechanical thermal analysis (DMTA). The composition and relative rate of reaction of the two orthogonal polymerisations influenced the extent of miscibility of the two polymer-rich phases and the samples were transparent, indicating that the two phases were finely dispersed. The addition of a glycidyl methacrylate compatibiliser further increased the miscibility of the two polymers. The utility of this polymer system for additive manufacturing was investigated and simulated through layer-by-layer processing of the mixture in two steps. Firstly, the methacrylate component was photocured to solidify the material into its final shape, whilst the second step of thermal curing was used to polymerise the epoxy component. With the use of a simulated photomask, a simple shape was formed using the two orthogonal polymerisation stages to produce a solid object. The mechanical properties of this two-phase system were superior to a control sample made only of the methacrylate component, indicating that some reinforcing due to polymerisation of the epoxy across the interfaces had occurred in the postcuring stage.

A Dyciandiamine-Based Methacrylate-Epoxy Dual-Cure Blend-System for Stereolithography

“…In the field of dual-cure systems for use in additive manufacturing, different promising approaches have already been pursued. Next to the common pure acrylate systems, many resin systems for SLA are based on the usage of the epoxy acrylates [ 14 ] or linking elements, which contain both an epoxy and an acrylate group, such as, e.g., 4-vinyl-1-cyclohexene 1,2-epoxide [ 15 ] or glycidyl methacrylate (GMT) [ 16 ]. While these systems use a dual-cure approach, the usage of these linking elements or acrylated epoxies is problematic as it results in low mechanical properties and weak light aging resistance [ 17 ] next to typical UV-acrylate problems such as the inhibition by oxygen.…”

Experiment-Based Process Modeling and Optimization for High-Quality and Resource-Efficient FFF 3D Printing

“…Especially in the aerospace sector, parts previously manufactured by traditional means are being replaced by additively manufactured lowweight polymer components. Although AM was previously primarily used to produce prototypes, it has now developed sufficiently for customized mass production of functional parts [8,9]. AM technologies can be classified into seven main categories [10,11] under which polymers can be 3D printed via polymerization, powder-bed-based processes, and extrusion-based processes [12].…”

Epoxy Based Blends for Additive Manufacturing by Liquid Crystal Display (LCD) Printing: The Effect of Blending and Dual Curing on Daylight Curable Resins

“…The vs epoxy content graph shows a quasi linear correlation considering only the high for the cream resin. This trend is typically observed for blends forming the so-called interpenetrated network [ 23 ].…”