Needle nucleating agent

Figure 5.20. Optical micrographs under crossed polars obtained at Tm= 80°C, for PP containing the needle nucleating agent (N,N -dicyclohexyl-2,6-naphthalenedicaiboxamide). MD (machine direction) represents the flow direction and TD denotes the transversal direction. [Adapted, by permission, from Yamaguchi, M Irie, Y Phulkerd, P Hagihara, H Hirayama, S Sasaki, Polymer, 51, 5983-9, 2010.]...

Many industrial semi-crystalline polymer materials like polypropylene, polyamides, or polyesters contain nucleating agents or clarifiers which form needle-shaped aggregates already in the polymer melt. "For this purpose the pattern is desmeared using the measured primary beam. For a less involved treatment it may be sufficient to know the integral width of the primary beam profile in fiber direction. 

To comprehend the molecular orientation, the orientation birefringence is evaluated using thin sliced films cut out the plaque containing needle crystals of the nucleating agent. The thin slice at the surface is blue (left picture), demonstrating that MD is the... 

Isotactic polypropylene composites with tetra-needle-shaped zinc oxide whisker were prepared via melt blending in a twin-screw extruder. The whisker is a p-nucleating agent, which offers higher crystallization temperature, smaller sphemlites, and faster crystalhzation rate than can be obtained in neat iPP. The addition of whisker also increases heat deflection temperature and thermal degradation temperature of iPP composite. ... 

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