Calculation and experimental verification of concentration profiles for selected species at the interphase generated by diffusion in polymer pairs

A generalized method to calculate diffusion rates in polydisperse systems. Further results on Rouse dynamics in the concentrated regime

“…[6] These beams were used for DMA measurements. The DMA method was used in the "direct form", [4] to verify the T g profiles calculated from simulated concentration distributions for each PS molecular weight present. T g profiles were calculated from composition profiles via an already used generalized Fox type equation.…”

“…T g profiles were calculated from composition profiles via an already used generalized Fox type equation. The calculated T g profiles were then used to simulate the expected DMA response (M N R versus temperature data) [4] which was then compared with the experimental results. Bending moment (M) and radius of curvature (R) for blends and composite beams were measured in a Perkin-Elmer DMA-7e.…”

“…This fact complicates considerably the calculations for diffusion rates of single species with narrow molecular weight distributions, as local composition-dependent properties have to be calculated for each point along the diffusion and time coordinates. [4] Diffusion rate calculations for polydisperse polymeric systems in the concentrated regime involve large amounts of work, as large systems of coupled differential equations may have to be solved for each point along the diffusion and time coordinates.…”

“…These calculations have been experimentally verified for bimodal mixtures of narrow molecular weight distributions. [4] The calculation method has been generalized to be used for polydisperse systems with broad molecular weight distributions with reasonable amounts of work. [5] The molecular weight range that corresponds to diffusion controlled by Rouse dynamics has received more attention in these articles, because this is the most important contribution for the short times involved in the preparation of blends and alloys at industrial scale.…”

Finite element model of interdiffusion and reaction in polydisperse polymer blends

“…The technique is then used to test the e ect of several processing parameters, including molecular weights distributions, interfacial reaction rates, and the e ects of catalysts and inhibitors. The accuracy of the numerical model is veriÿed through comparison with some experimental results published earlier [9].…”