Abstract
The effect of liquid-liquid phase-separation (LLPS) on the crystallization behavior and mechanical properties of poly(ethylene-ran-vinyl acetate) (EVA) and paraffin wax blend was investigated. The blend of EVA and the wax became homogeneous at temperatures greater than its upper critical solution temperature (UCST) (371K), and an LLPS was observed between UCST and the melting point of 361 K for EVA in the blend. The degree of crystallinity of EVA in the blend, judged from a melting endothermic peak in differential scanning calorimeter (DSC) thermograms obtained during heating runs, decreased with increasing duration time in the LLPS region.
The flexural modulus of the blend became maximum at the 35wt% EVA. This behavior can be explained by the fact that this blend composition has the largest relative degree of crystallinity of EVA measured by DSC. We found that the flexural modulus of the binder itself is directly related to that of a feedstock consisting of larger amounts of metal powder and the binder, which can help someone to develop a suitable binder system for a powder injection molding process.
