Editing Epoxy (section)

=== Anhydrides ===

Epoxy resins may be thermally cured with anhydrides to create polymers with significant property retention at elevated temperatures for extended periods of time. Reaction and subsequent crosslinking occur only after opening of the anhydride ring, e.g. by secondary hydroxyl groups in the epoxy resin. Homopolymerization may also occur between epoxide and hydroxyl groups. The high latency of anhydride hardeners makes them suitable for processing systems which require addition of mineral fillers prior to curing, e.g. for high voltage electrical insulators. Cure speed may be improved by matching anhydrides with suitable accelerators. For dianhydrides, and to a lesser extent, monoanhydrides, non-stoichiometric, empirical determinations are often used to optimize dosing levels. In some cases, blends of dianhydrides and monoanhydrides can improve metering and mixing with liquid epoxy resins.<ref>{{Cite web|last=Mishra|first=Vinay|date=2020|title=Benefits and Applications of BTDA and Other Dianhydrides in Polyimide and Epoxy Resins|website=[[YouTube]]|url=https://www.youtube.com/watch?v=YKoSez98UlM| archive-url=https://ghostarchive.org/varchive/youtube/20211107/YKoSez98UlM| archive-date=2021-11-07 | url-status=live}}{{cbignore}}</ref>