Rheological and Thermal Behavior of Recycled PET Modified by PMDA
In this work pyromellitic dianhydride (PMDA) was used as the chain extender to increase the molecular weight of the recycled poly(ethylene terephthalate) (R-PET) and improve the rheological properties of the R-PET. The reaction was performed in a Brabender torque rheometer. The rheological and thermal characterization were performed by means of a fusion index instrument and a differential scanning calorimeter (DSC ) to compare the effectiveness of the chain extending reaction of different percentages of PMDA. The experimental results showed that compared with the unmodified R-PET, the addition of PMDA decreased the melt flow index and increased the viscosity of the R-PET. In addition, increased crystallization temperatures ( ) were observed with the modified R-PET. It was also found that the modified R-PET with the concentration of 1.0wt% PMDA exhibited the lowest MFI.