SPE Library

Elevating Aerospace Composite Manufacturing: The Role of Thermal Analysis In Maximizing Efficiency And Minimizing Waste

Alec Redmann and Ryley Karl, May 2023

Thermosets and composites can be difficult materials to use in serial production. How do you know what combinations of curing temperatures and time can be used? When is it safe to demold parts? And are the final properties what you expect? Without this information, it is impossible to optimize your cycle times and minimize waste. This webinar will introduce how thermal analysis is being utilized by DarkAero to manufacture high-performance two-seat aircraft and composite structures with a new level of technical understanding and engineering confidence. The material covered will include:

• Fundamentals of manufacturing composite structures and sandwich panels.
• Differential scanning calorimetry (DSC) and how it is used to understand curing reactions.
• Curing kinetics and simple methods to reduce cycle times.
• High-force dynamic mechanical analysis (DMA) and how it enables unprecedented evaluation of structural composites.

Developing Photopolymerizable Acrylate Resin Formulation for Impact Modified 3D Printed Thermosets

Chinmay Saraf | Amy Niu | Alan J. Lesser,, April 2021

This contribution focuses on engineering photopolymerizable acrylate resin formulations for a superior fracture energy absorption of 3D printed acrylate thermosets. Herein, we report a polydimethyl siloxane-based block copolymer as an impact modifier, compatible with the UV curing process, which undergoes reaction induced phase-separation during the 3D printing process to form a rubbery phase sufficient for enhanced impact properties. A systematic investigation of the effect of concentration of the impact modifier on the morphology of rubbery domains and fracture toughness was conducted. Results show that at an optimum concentration of 15 wt.% and particle size of 57 nm, an order of magnitude improvement in the fracture energy release rate is realized. Fractographic analysis of the impact modified thermosets using optical microscopy indicates the presence of significant plastic deformation in an otherwise brittle material. Notably, the engineered acrylate thermosets, at an optimum concentration, exhibit similar improvements in the impact properties irrespective to the print layer thickness and independent of the crack orientation with respect to the printed interphase. Detailed investigation of the failure mechanisms for impact modified thermosets show that the block copolymer diffuses to the interphase during the 3D printing process, resulting in preferential localization of the impact modifier near the print interphase resulting in an isotropic enhancement of the fracture toughness.