A Quantitative Estimation of the Extent of Compatibilization in Heterogeneous Polymer Blends Using Their Heat Capacity Increment at the Glass Transition

摘要

In this paper a new method based on the determination of heat capacity increment at the glass transition (#DELTA# Cp) is presented to quantify the effectiveness of compatibilizers for immiscible polymer blends.In order to thow the validity of the method,two immiscible blends,polypropylene-poly(ethylene terephthalate) (PP-PET) and PP-polyamide-6,6 (PP-PA66),and two compatibilizers,N,N-dihydroxyethyl monomaleic amide-grafted PP (g-PP) alone and together with a phenolic resin (PR),were investigated.Scanning electron microscopy (SEM) observations prove that the two compatibilizer systems are both effective for compatibilizing the blends,and the combined use of g-PP and PR is more effective than g-PP alone.Modulated-temperature differential-scanning calorimetry (M-TDSC) determinations reveal that the #DELTA# Cp varies with the extent of compatibilization.For the uncompatibilized blends,the #DELTA# Cp for the PET component in PP-PET or for the PA66 component in PP-PA66 was found to be almost unchanged.After compatibilization these quantities become smaller.Also,the combined use of g-PP and PR results in the smallest #DELTA# Cp values for both blends.This #DELTA# Cp change with different compatibilizers is in very good agreement with the corre-sponding morphological variation observed by SEM.Thus,#DELTA# Cp can be taken as a new parameter for quantifying the extent of compatibilization,since it is a direct measure of interfacial content.