In our previous study, chromium acetylacetonate (Cr(acac)3) was found to have a greater toughening effect on epoxy resin than Co(acac)3. G.p.c. and n.m.r, results indicated that Cr(acac)3 has a tendency to attach to the hydroxy groups of diglycidyl ether of bisphenol A (DGEBA) multimers during mixing. This is due to the fact that the (acac)- ligands of Cr(acac)3 are able to attract protons from hydroxy groups. As the DGEBA epoxy resin incorporating Cr(acac)3 was cured with amine curing agents, each Cr(acac)3 molecule was able to interact with more than one hydroxy group. This reinforced the cured epoxy network unless the amine curing agents exceeded the stoichiometric quantity of epoxy groups.
Посилання на статтю:
Organotransition metal complexes as additives for epoxy resins: 2. Interaction with epoxy resins / King-Fu Lin*, Wen-Yung Shu and Tain-Luen Wey // Polymer. – 1993. – Vol 34. – P. 2162-2168.