TNT/TNB及TNT/BTF共晶结晶动力学研究OA

To study the structural recoverability and non-isothermal crystallization kinetics of 2,4,6-trinitrotoluene/1,3,5-tri-nitrobenzene(TNT/TNB)cocrystal and TNT/benzotrifuroxan(TNT/BTF)cocrystal subjected to melt-cooling cycles,cocrystal samples were initially prepared via the melt-casting method.Powder X-ray diffraction and variable-temperature X-ray diffrac-tion were employed to monitor structural evolution,while differential scanning calorimetry(DSC)was used to characterize thermal and crystallization behaviors.The results reveal that after repeated melting and solidification,the TNT/TNB cocrystal consistently exhibits the same melting temperature(62 ℃)and crystallization temperature(32 ℃).Similarly,the TNT/BTF cocrystal also retains its melting temperature(132 ℃)and crystallization temperature(58 ℃),demonstrating that both co-crystals can faithfully reconstruct their original cocrystalline phases upon melt recrystallization.Kinetic analysis using the Avrami equation modified by the Jeziorny method yields Avrami exponents of 2.40 for TNT/TNB cocrystal and 2.20 for TNT/BTF co-crystal,indicating essentially identical growth mechanisms:a mixed mode between two-and three-dimensional growth,exhibi-ted by rapid nucleation followed by a prolonged crystal growth stage.Furthermore,the Mo's equation was applied to analyze the crystallization kinetics.The resulting parameters show that the crystallization rates of both cocrystals decrease with increas-ing relative crystallinity.