Showing 12 results for Author: Derek B. Dwyer
Jun, 2026
Journal
Diglycidyl ether of bisphenol F (DGEBF) is a common industrial epoxy resin, desired for its possible replacement of the bisphenol A (BPA) analogue DGEBA due to potential health hazards of BPA. During curing, crystallization of the DGEBF resin can cause inaccurate resin-to-hardener ratios, resulting in incomplete crosslinking; therefore, understanding the crystallization of…
Dec, 2025
Journal
Polymer network structures in epoxy thermosets play an important role in the final thermoset material properties. However, analytical characterization of these network structures is difficult due to their amorphous nature. In this work, the application of evolved gas analysis–mass spectrometry (EGA-MS) to characterize the polymer network structures of bisphenol A (BPA)-bas…
Aug, 2025
Journal
Defects play a significant role in the material properties of carbon fibers (CF). Several defects result in the formation of sp3 bonds in an otherwise sp2-dominant graphitic structure. Understanding the distribution of these defects within CF provides insight into their properties and the effect of manufacturing conditions. Reports showed time-of-flight secondary ion mass…
Apr, 2025
Journal
Detonation nanodiamonds (DNDs) are formed at specific pressures and temperatures during explosions. Different explosives produce varied yields of DNDs within their detonation soot, with Composition B producing the highest yield. Raman spectroscopy (RS) is often used for the characterization of sp2- and sp3-hybridized carbon allotropes in carbonaceous materials because of d…
Dec, 2024
Journal
Analysis of byproducts from thermal degradation of polymer materials provides a wealth of information about a materials’ composition, thermal stability, degradation mechanisms, and kinetics. However, regardless of the instrumentation used, only limited information is obtainable from a single experiment. Microfurnace technology, when interfaced to a gas chromatography-mass…
Apr, 2024
Journal
Crystallization is a common problem for epoxy resins, which are ubiquitous in industrial and commercial use. Integration of crystallized epoxy monomers into cured thermosets has been shown to alter the thermosets’ final mechanical properties. However, no studies have investigated the impact of these crystals on the thermal stability of the thermoset. Here we investigate th…
Nov, 2023
Journal
Understanding the thermal pyrolysis of epoxies and their copolymers is important for identifying structural changes resultant from thermal transients, enabling identification of failure modes of high-performance composite materials. This work expands our understanding of the thermal pyrolysis of cured epoxies and the role of temperature and composition on products, pathway…
Nov, 2023
Journal
Good wettability of separators in batteries and capacitors is crucial for performance. Titanium hydroxide (Ti(OH)x) has been shown to greatly improve the wettability of polyvinylidene fluoride (PVDF) nanofibers (NFs). In this work, PVDF/Ti(OH)x NFs were evaluated for their potential use as separators. Results show that PVDF NFs incorporated with Ti(OH)x have improved elect…
Nov, 2023
Journal
Knowledge of the degradation kinetics for polymer materials is important for understanding thermal stability. Here, evolved gas analysis–mass spectrometry and pyrolysis gas-chromatography-mass spectrometry were evaluated for the potential to deliver additional insight into thermal degradation kinetics of diglycidal ether of bisphenol F (DGEBF) epoxy thermoset under inert a…
Nov, 2023
Journal
Bisphenol F (BPF) epoxy resin is a prepolymer component of thermosets used in construction of reinforced carbon fiber composites (RCFC). The fluorescence of this resin can provide information about chemical and structural alterations of the thermoset from thermal or mechanical damage. While some work has investigated the fluorescence spectra of bisphenol A epoxy resin, a s…
Nov, 2023
Journal
The polymer network structure of epoxy thermosets plays a significant role in its final material properties. However, the effects of mild thermal exposure on these network structures are poorly studied. In this work, wide-angle X-ray scattering was used to investigate the polymer network structure of two epoxy thermosets: homopolymerized bisphenol A (BPA) epoxy resin and B…