Professor Chris Macosko – Analyzing Molecular Weight Distribution w/ Rheology
In this TA Instruments Webinar, Professor Chris Macosko discusses analyzing molecular weight distribution and blend morphology using rheology. Rheology is a powerful tool for analyzing polymer blends. This seminar will begin with the simplest case: molten blends of two different molecular weight homopolymers.We will learn how, using the reptation model, rheology can determine molecular weight distribution. The model will then be extended to miscible blends of two different polymers by incorporating the shift in their glass transitions to capture the self concentration of each polymer. Immiscible blends introduce phase morphology and interfacial tension forces. Rheology can be used to measure droplet size and size distribution. Novel porous structures can be created from cocontinuous polymer blends. Rheology can assess their stability and detect interfacial reactions. At high shear stresses interfaces slip leading to anamolous rheology. The strengths and limitations of rheology as a tool for characterizing polymer blends will be summarized.
