Synthesis And Characterization Of The Boric Acid Ester Coupling Agent And Borate Whisker Modified Polymer

A series of boric esters-type coupling reagents differentiated by their diversely branched butoxy groups were synthesized to probe how the coupling reagents'structure influence their own water-persistence and the whiskers/resin interface. Control experiments were carried to decide the optimum reaction condition. The structure of the boric esters were exactly characterized by 1H NMR spectrum instead of the reported FT-IR methods, and their hydrolytic stability, solubility and other physical properties were investigated. Hydrolytic experiments indicated that the most highly branched boric ester tert-BE4 showed the best water-persistence because the bulky tert-butoxy group restrained the nucleophilic attack on the boron atom by water.The synthesized boric esters-type coupling reagents and classical silane-type coupling reagentγ-amino propyl triethoxy silane(KH550) were used in borate whiskers reinforced epoxy resincomposites, and the mechanical properties and interfacial morphology of composites were measured(by SEM). The results came into two conclusions: 1. The synthesized boric esters-type coupling reagents performed better than the classical silane-type coupling reagents, and furthermore, tert-BE4 performed the best in all; 2. Both aluminium borate whiskers and magnesium borate whiskers enhanced the interaction between resin and whiskers and the mechanical properties of composites, while magnesium borate whiskers reinforced epoxy resin composites gave better mechanical properties than those with aluminium borate whiskers.