Hello, everyone I would like to know the difference between MWD(molecular weight distribution) from SEC(GPC) and PI(polydispersity index)from rotational rheometer data. In my experience, their values have some difference. what do you think about that?
Thank you
To me, neither technique is best considered an absolute measurement of molecular weight. Both have some other "standard" that they are being compared to, whether it is a polystyrene or a (semi-)emperical correlation from the literature. The end result is that each technique is best used for comparisons to other measurements of similar polymers using the same technique. Nobody wants to hear that as it is too limiting. So we treat them as thought they were all accurate and absolute and then we get in to trouble.
John Aspen Research, -
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