Evaluation of the fractionated crystallization of dispersed polyolefins in a polystyrene matrix

Nucleation and crystallization of isotactic poly(propylene) droplets in an immiscible polystyrene matrix

“…For blends of isotactic poly(propylene) (iPP) and PS, we were able through the use of a compatibilizing agent to create a very fine dispersion of PP droplets well into the submicron size. [15] In that case, only one exotherm for the iPP crystallization was observed at 45 8C, this is one of the lowest temperature values reported for PP crystallization and we presented evidences that could indicate that this value may be close to the homogeneous nucleation temperature for this polymer. Ghijsels et al [12] have also reported small exotherms corresponding to iPP droplet crystallization in blends with ethylene/propylene rubber at similarly lower temperatures (in their case other higher temperature exotherms were always present) but interpreted them as the crystallization of iPP in a smectic phase.…”

“…We are aware that coalescence due to annealing in the melt could affect the sample morphology and therefore the fractionated crystallization process (see for instance ref. [15] and [18] ). Micrographs were obtained from which the average number and volume diameters (d n and d v ) of the particle crosssections were measured by counting at least 100 particles.…”

“…The number and volume average diameters were obtained using equations given elsewhere. [15] Wide angle X-ray diffraction…”

“…Most of these works have been reviewed by Frensch et al [1] and Arnal et al [15] The fractionated crystallization phenomena of polyolefins have been the subject of several recent investigations. [14][15][16][17][18][19][20][21] Ref. [15] presents a recent short review of current literature dealing with this subject.…”

“…[14][15][16][17][18][19][20][21] Ref. [15] presents a recent short review of current literature dealing with this subject. For blends of isotactic poly(propylene) (iPP) and PS, we were able through the use of a compatibilizing agent to create a very fine dispersion of PP droplets well into the submicron size.…”