Structural Variation and Chemical Performance—A Study of the Effects of Chemical Structure upon Epoxy Network Chemical Performance

Abstract

Epoxy resins are used widely as protective coatings, in a wide range of harsh chemical environments. This work explores the influence of subtle structural variation in both epoxy and amine monomers upon chemical performance of cured networks, whether changing molecular geometry, the nature of the chemistry, or the mass between cross-linking reactive groups. To achieve this, four industrially relevant epoxy resins (two based on bisphenol A—Epikote 828 (E828) and Dow Epoxy Resin 332 (DER 332)—and two based on bisphenol F—Dow Epoxy Resin 354 (DER 354) and Araldite PY306 (PY306)) and the isomerically pure para–para-diglycidyl ether of bisphenol F (ppDGEBF) were used to explore variation caused by epoxy monomer variation. Four similar amines (meta-xylylenediamine (MXDA), para-xylylenediamine (PXDA), 1,3-bis(aminomethyl)cyclohexane (1,3-BAC), 1,4-bis(aminomethyl)cyclohexane (1,4-BAC)) were used to explore any variations caused by regioisomerism and aromaticity. Bisphenol F-based resins were found to outperform bisphenol A-based analogues, and chain extension within the epoxy component was found to be detrimental to performance. For amines, 1,3-substitution (vs 1,4) and aromaticity were both found to be beneficial to chemical performance.

Experimental and Theoretical Study of Gamma Radiolysis and Dose Rate Effect of o-Cresol Formaldehyde Epoxy Composites

“…Owing to the excellent chemical and heat resistance, adhesion, low shrinkage and mechanical strength, and friendly molding processability, thermoset epoxy resins are extensively used in nuclear power plants, aerospace vehicles, and satellites, serving as coating, adhesives, encapsulation compounds for electrical equipment, and reinforced structural composites . Epoxy resins synthesized by diglycidyl ether of bisphenol A/F and amine/anhydride hardeners with various structures are the most frequently used ones . Silica is usually added into the epoxy as a filler to improve its toughness, thermal conductivity, and insulating property but decrease the linear expansion coefficient .…”

“…1 Epoxy resins synthesized by diglycidyl ether of bisphenol A/F and amine/ anhydride hardeners with various structures are the most frequently used ones. 2 Silica is usually added into the epoxy as a filler to improve its toughness, thermal conductivity, and insulating property but decrease the linear expansion coefficient. 3 Although a great many epoxy resins have been applied in the radiation environments, high-performance epoxy resins are still in need to satisfy the application requirement under the harsh conditions.…”

Effect of the linking positions on the benzene ring on properties of poly(silane arylether arylacetylene)s

“…Although the chemical compositions of three isomeric resins are identical, the segmental motions in the crosslinking networks with the –Ph–O–Ph–O–Ph– unit (see Figure 5E) at elevated temperature can differently occur. The cured pmp ‐PSEA and pop ‐PSEA resins could undergo segment motions, resulting in higher β ‐transition temperature and stronger β ‐transition peak (tanδ) compared with cured ppp ‐PSEA resin 45–49 . For three cured resins, storage modulus drops at first and then increases corresponding to the movement of local segments and further crosslinking reactions of internal alkynyl groups, respectively.…”

“…The cured pmp-PSEA and pop-PSEA resins could undergo segment motions, resulting in higher β-transition temperature and stronger β-transition peak (tanδ) compared with cured ppp-PSEA resin. [45][46][47][48][49] For three cured resins, storage modulus drops at first and then increases corresponding to the movement of local segments and further crosslinking reactions of internal alkynyl groups, respectively.…”

Recyclable thermosets based on modified epoxy-amine network polymers

“…However, it is essential that high-performance epoxy-thermosets exhibit a broad spectrum chemical resistance, remaining undamaged and insoluble upon exposure to chemically aggressive liquids and solutions. [47][48][49] Immersion of the epoxy-amine-dioxazaborocane D100, in a range of solvents including ethanol, DMSO, toluene, acetone, THF, distilled water and 1 M NaOH showed no material integrity loss with the expected excellent chemical resistance and insoluble properties of a 'traditional/epoxy-amine' thermoset, network polymer. The hydrolytic stability under aqueous conditions, can be attributed to the enhanced stability of boronic esters containing tetra-coordinate bonding via N-atom coordination, 50,51 such as that seen in the bicyclic dioxazaborocane structures described here.…”