High Performance Gel Permeation Chromatography

Abstract

rate is of great importance when examining high molecular weight samples and high speed is of use when separating oligomers by GPC. A linear plot of log polydispersity versus .flow rate. for a broad distribution polystyrene was also constructed. It was demonstrated that this plot can be extrapolated to zero flow rate to ~ive_an intercept from which the true polydispersity of the polymer can determined provided that the contribution owing to eddy diffusion was minimal. lIowever. at the lowest flow rate examined it was demonstrated that broadening was still present. The work shows that GPC is a very useful technique for measuring molecular weight distributions. These can be determined quickly and/or accurately depending on the molecular weight of the sample.

Dynamic viscoelastic behavior and interlaminar performance of glass/epoxy composites with binary nano‐fillers at different in‐situ elevated temperature environments

“…As the temperature rises, both glass fiber (reinforcement) and epoxy (matrix) want to inflate, and the rate of enlargement is determined by their corresponding thermal expansion coefficients (CTE). Cured epoxy has a CTE in the range of 55–80 ppm/°C, [ 30 ] which is much greater when compared with the order of glass fiber 5–12 ppm/°C. [ 31 ] As a result, glass fibers' radial expansion is much slower than that of the epoxy around them, resulting in residual internal strain at their contact.…”