摘要
Dual endotherms during differenUal scanning calorimetric (DSC) measurement occur when dried PET pellets are pretreated with solld state polyeondensation (SSP) at 215-230℃ for appropriate holding, times. The two endothermic fusion peaks arise from melting and recrystallization, taking place during scanning in the calorimeter,of imperfect crystals initial present in sample. The lower temperature peak appears higher than the SSP reaction temperature for 5-20℃ accordingly and linear relaflonship with SSP reaction temperature, logarithmic linear relationship vs. SSP reaction time, while the position of higher temperature peak nearly does not change. The higher the SSP reaction temperature, the larger the total area of the endotherms, namely, the higher crystallinity. For 4 reaction temperatures the crystallinity show logarithmic linear relationship vs, SSP reaction time.
Dual endotherms during differential scanning calorimet-ric (DSC) measurement occur when dried PET pellets are pretreated with solid state polycondensation (SSP) at215 - 230 ℃ for appropriate holding times. The two en-dothermlc fusion peaks arise from melting and recrystal-lization, taking place during scanning in the calorimeter, of imperfect crystals initial present in sample. The lower temperature peak appears higher than the SSP reactiontemperature for 5 - 20℃: accordingly and linear relationship with SSP reaction temperature, logarithmic linear relationship vs. SSP reaction time, while the position of higher temperature peak nearly does not change. The higher the SSP reaction temperature, the larger the total area of the endothenns, namely, the higher crystallini-ty. For 4 reaction temperatures the crystallintty show logarithmic linear relationship vs. SSP reaction time.
