Effect of syndiotactic polystyrene on the crystallization behavior of isotactic polypropylene/syndiotactic polystyrene blends with and without β‐nucleating agent

Abstract

Blends of isotactic polypropylene (PP) and syndiotactic polystyrene (sPS) with and without β-nucleating agent were prepared using a twin-screw extruder at 290 • C. Blends of PP/sPS with β-nucleating agent mainly show β crystalline form, irrespective of high (20 • C min −1 ) or low (2 • C min −1 ) previous cooling rates. This suggests that the cooling rates have little effect on the polymorphic composition of PP in PP/sPS blends. The effect of sPS on the crystallization of PP is compared with that of polyamide 6 (PA6). The increase in crystallization temperature of PP is smaller in the presence of sPS than in the presence of PA6; the fold surface free energy of PP/sPS is larger than that of PP/PA6 blends. These results reveal that compared with PA6, sPS has much weaker α-nucleation effect on the crystallization of PP. The weak α-nucleation effect of sPS is attributed to the high lattice mismatch between PP and sPS crystals.

The influence of glass fibers on the morphology of β-nucleated isotactic polypropylene evaluated by differential scanning calorimetry

“…The characteristic morphology of β-spherulites, originating after mixing iPP with Ca-pimelate, is also clearly illustrated in Fig. The Avrami plots for BNP and the model BNP/glass fiber composites in the investigated region of crystallization temperatures, similarly to other β-nucleated systems, [42][43][44] were almost linear (Fig. The K β parameter determined from the XRD-patterns by the Turner-Jones method 35 was 0.94, while the U β -value calculated from the melting endotherm was 0.84 ( Fig.…”

“…Generally, different values for σ e are reported in the literature, mostly depending on the investigated region of crystallization. al for β-nucleated iPP compared to 107, mJ m -2 for the neat polymer 43. The value of 85.5 mJ m -2 was determined by Li et.…”

The effects of sonication time and frequencies on degradation, crystallization behavior, and mechanical properties of polypropylene

“…Generally, two methods have been extensively used to modify the toughness of PP. One is compounding with toughening modifiers [2][3][4][5], while the other is modifying the crystalline form of PP [6][7][8][9][10][11][12][13][14][15][16], typically the formation of b2form PP which demonstrates the higher performance, such as a higher elongation at break and a higher impact strength. Adding toughening modifiers is a simple, economical, and commonly used strategy.…”