Title: Low-CTE Functional Nanocomposites for High-Precision Stereolithography

Authors: Rahul Sheley, JITENDRA TATE, Sachin Shendokar, Shourav Ghosh

DOI:

Abstract: Stereolithography (SLA)-printed polymers used in aerospace applications often require metallic coatings, commonly nickel. However, these coatings tend to fail at elevated temperatures due to mismatches in the coefficient of thermal expansion (CTE) between the polymer resin and the metal. This research aims to investigate the development and thermal characterization of hybrid multi-scale epoxy-based nanocomposites with reduced CTE to improve compatibility with nickel coating. A nanocomposite resin system was formulated using bisphenol A epoxy diacrylate (EBECRYL® 3700) as the base oligomer, trimethylolpropane triacrylate (TMPTA) as a reactive diluent, and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) and bis (2,4,6trimethylbenzoyl)-phenylphosphine oxide (BAPO) as photoinitiators. Nanosilica (25–55 wt%) and functionalized hexagonal boron nitride (h-BN, 0.5–2 wt%) were incorporated individually and as a multiscale hybrid reinforcement. Rheological behavior, thermomechanical properties, and thermal stability were systematically evaluated. All formulations exhibited shear-thinning behavior suitable for SLA processing. Thermomechanical analysis revealed a progressive reduction in CTE from 136.8 μm.m⁻¹ °C⁻¹ for the neat resin to a minimum of 103.2 μm.m⁻¹ °C⁻¹ for the hybrid system containing 55 wt% SiO₂ and 2 wt% h-BN. Differential scanning calorimetry showed moderate glass transition temperatures (38–57 °C) and a pronounced residual-cure exotherm between 60°C and 150°C, indicating incomplete photocuring and the need for post-curing. Thermogravimetric analysis demonstrated a single-step degradation at 440460 °C, with increased ceramic content increasing residual mass and enhancing high-temperature stability. The results establish clear processing–structure–property relationships and demonstrate that multiscale ceramic reinforcement is an effective strategy for producing dimensionally stable SLA resins suitable for nickel metallization and thermally demanding aerospace applications.

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Conference: SAMPE 2026

Publication Date: 2026/04/27

SKU: 88

Pages: 16

Price: $32.00