Highly efficient nucleating additive for isotactic polypropylene studied by differential scanning calorimetry

Abstract

ABSTRACT:The influence of an organic phosphate derivative in the crystallization of the monoclinic phase of isotactic polypropylene was studied by differential scanning calorimetry. To analyze the nucleation activity of the additive, the self-nucleation process of the pure polymer was also studied by thermal techniques. A large increase in crystallization temperatures was obtained even for the lowest concentration of the additive, and its nucleating efficiency is the highest observed for ␣-nucleating agents in isotactic polypropylene. The nucleating agent was also observed to increase the stability of the crystals formed.

Effect of the Molecular Structure of the Polymer and Nucleation on the Optical Properties of Polypropylene Homo- and Copolymers

“…After the quantitative analysis of these correlations an attempt is made to relate the determined parameters to the molecular structure of the polymer. Nucleation is very often used in polypropylene to increase stiffness and strength [23][24][25][26][27][28][29] , to improve productivity by increasing the temperature of crystallization [27][28][29][30] and to modify optical properties [17][18]31 . The efficiency of nucleation is usually estimated by DSC measurements, by changes in the peak temperature of crystallization (T cp ) 32 , which can be related to the thickness of the lamellae formed 33 .…”

Activity of a β‐nucleating agent for isotactic polypropylene and its influence on polymorphic transitions

“…The characterization is described elsewhere. 39 The nucleating agent was N,NЈ-dicyclohexyl-2,6-naphthalene dicarboxamide (NJSTAR NU100) supplied by NJC-RIKA. The nucleated systems were prepared by melt blending in a twin-screw extruder with a NJSTAR NU100 concentration between 0.05 and 0.3% by weight, using the conditions previously described.…”

Caracterización de la heterogeneidad estructural en polipropileno polimórfico mediante espectroscopia vibracional: microscopia IR y Raman

“…Dos de ellos fueron grados comerciales de reactor denominados P1 (peso molecular promedio viscoso, Mv = 164,700 [4]) y P2 (Mv = 116,200, índice de polidispersidad, I.P. = 4), y el tercero, un grado de reología controlada, denominado P3 (Mv = 100,000, I.P.…”

“…Se emplearon 3 agentes nucleantes de diferente naturaleza; 1,3: 2,4-bis-(3,4-dimetilbenziliden sorbitol), MILLAD 3988 de Milliken Chemical, denominado n1, N,N´-diciclohexíl-2,6-naftalén dicarboxamida, NJ-STAR NU100 de NJC-Rika, denominado n2, y ácido pimélico, denominado n3. Una serie de materiales polimórficos, P1+n1 y P1+n2, fueron preparados a concentraciones de agente nucleante entre 0,025 -1,0 % en peso, mediante mezclado en una extrusora de doble husillo utilizando las condiciones descritos en un trabajo anterior [4]. Otra serie de muestras, P2+n3 y P3+n3, fueron preparadas a partir de una disolución 0,25M en CHCl 3 a concentraciones entre 0,025 -1,0 % en peso de n3, utilizando un método similar al descrito por Wang [6].…”

“…Otra serie de muestras, P2+n3 y P3+n3, fueron preparadas a partir de una disolución 0,25M en CHCl 3 a concentraciones entre 0,025 -1,0 % en peso de n3, utilizando un método similar al descrito por Wang [6]. Se prepararon películas delgadas mediante compresión a partir del fundido, y posteriormente fueron sometidas a una fusión previa entre portas de microscopio para eliminar la historia térmica [4], y cristalizadas a distintas velocidades de enfriamiento, en una célula de temperatura Mettler FP80T acoplada a un microscopio Reichert Zetopan-Pol de luz polarizada. En último término su comportamiento térmico y morfología fue analizado por DSC, WAXD y análisis termoóptico [7][8][9].…”