Ostwald ripening in an immiscible hydrogenated polybutadiene and high‐density polyethylene blend

Abstract

The long‐time regime coarsening in a phase‐segregated blend of hydrogenated polybutadiene (HPB) with high‐density polyethylene (HDPE) was studied. The blend consisted of 10 wt% of HPB in a HDPE matrix. The morphology of the system was studied by etching the HPB particles from the HDPE matrix and observing the etched specimens in a scanning electron microscope. The average volume of the HPB particles was found to increase with storage time in the melt, and to follow a temporal exponent of 1 in agreement with the predictions of the Ostwald ripening theory. This indicated that the particles coarsen by the evaporation‐condensation mechanism on which the Ostwald ripening theory is based. The rate constant from the Ostwald ripening theory was calculated and compared to the rate constant determined from the experimental data. The theoretical rate constant, K, calculated from Ostwald ripening theory, was 3.6 × 10−18 cm3/s compared to an experimentally determined rate constant of 4.8 × 10−18 cm3/s. The agreement between the theoretical and experimental rate constants was quite good. The significance attached to the good agreement between the theoretical and experimental rate constants might be mollified to some extent by the uncertainty involved in the parameters used to calculate the theoretical rate constant; viz. the interfacial tension, mutual‐diffusion coefficient, and equilibrium concentration of the HPB in the matrix phase that are not known to high accuracy. In reality, because other theories were used to determine the interfacial tension, mutual‐diffusion coefficient, and equilibrium phase compositions, this study was a test of several theories simultaneously. However, the agreement of the experimental temporal exponent and rate constant with the predictions of Ostwald ripening theory strongly indicates that the HPB/HDPE system coarsens by the evaporation‐condensation mechanism upon which the Ostwald ripening theory is based. © 1994 John Wiley & Sons, Inc.

Morphology evolution and location of ethylene-propylene copolymer in annealed polyethylene/polypropylene blends

“…If the EPR copolymer behaves like a surfactant reducing the interfacial tension and stabilizing ripening). [37][38][39] Quantifying the contribution of each process here is difficult. The larger domains the system, two major effects should be detectable in a PE/EPR/PP blend: a slowing down of the of the PE phase formed are not spherical, and coarsening rate and the formation of a finer disratio, and examine the effects of the copolymer on the morphology of the system.…”

Polymer Films with Embedded Metal Nanoparticles

“…In these cases, the rate equation (4.4) generally holds. Furthermore, LSW theory is used to describe size changes in polymer mixtures (poly butadiene particles in polyethylene [393]) or for the growth of gas bubbles in metals (10 nm helium bubbles in precious steel [394]) . Furthermore, LSW theory is used to describe size changes in polymer mixtures (poly butadiene particles in polyethylene [393]) or for the growth of gas bubbles in metals (10 nm helium bubbles in precious steel [394]) .…”

Modeling the effect of compatibilizers in the coarsening of ternary polymer blends with core-shell morphology

“…This finding has led to the general acceptance of the Lifshitz–Slyozov–Wagner (LSW) model for the time dependence of the average particle radius:11 where the value of K varies with the ripening mechanism 9. Both experiments1, 2 and numerical simulations15 based on the Cahn–Hilliard theory have shown that the coarsening process follows eq 2 in binary systems. In addition, the nonlinear diffusion model is capable of predicting both Ostwald ripening and particle coalescence.…”

“…The coarsening of particles in a phase‐separated polymer blend has received much attention in the recent literature 1–9. This is due in part to the importance of particle size with respect to the physical properties of a given blend.…”