The effect of talc on the crystallization of isotactic polypropylene

Abstract

Isotactic polypropylene (iPP) has been crystallized in the presence of talc under the quiescent state and shear flow of injection molding. The resulting morphology has been investigated by means of polarizing microscopy, transmission electron microscopy, and wide angle X‐ray diffraction. In the quiescent state, the iPP lamellae grew from the surface of talc and the transcrystalline region was formed at the interface between iPP melt and the talc. The nucleation of iPP was very frequent on the cleavage plane of talc. The X‐ray diffraction pattern of the transcrystal showed a*‐axis orientation to the crystal growing direction. In injection‐molded samples of the talc‐filled iPP, the morphology of lamella growing from talc appeared as same as that of the transcrystal. However, the crystalline orientation of injection‐molded talc‐filled iPP, in which the b axis was oriented to the thickness direction and the a* and the c axis was oriented to the flow direction, was quite different from that of the transcrystal. This b‐axis orientation results from the orientation of the plate plane of talc, which induces the nucleation and the crystallization under shear flow. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1693–1703, 2001

Crystallization kinetics of poly(butylene terephthalate) and its talc composites

“…[32][33][34] In this study, we have confirmed the nucleation and crystallization efficiency of talc containing PBT. [32][33][34] In this study, we have confirmed the nucleation and crystallization efficiency of talc containing PBT.…”

Chemical modification routes of synthetic talc: Influence on its nucleating power and on its dispersion state

“…Widely used in many industrial areas such as paper, paints, ceramics, cosmetics and pharmaceutics, talc is very frequently added to polypropylene (PP) to improve its mechanical properties, its thermal resistance and its dimensional stability and all these at a low cost. It is well known that talc acts as a nucleating filler (Naiki et al, 2001;Ferrage et al, 2003) thereby modifying the crystallinity and consequently the mechanical properties of PP (Premalal et al, 2002;Leong et al, 2004;Lapcik et al, 2008). Usually, the fine spherulitic microstructure achieved in PP after adding talc greatly enhances ductility and strength.…”

Optimization of the crystallinity of polypropylene/submicronic-talc composites: The role of filler ratio and cooling rate

“…In the case of polymer matrices such as iPP having poor if any interaction with the nanofillers, surface treatment techniques of the nanoparticles were required as well as specific preparation methods involving the use of compatibilizing agents. Among mineral fillers, talc proved to have a good potential of development for iPP-based composites, noticeably in the automotive industry [13][14][15][16][17]. It appeared very soon that talc displayed a strong nucleating effect for iPP [14,[19][20][21][22][23] due to specific physico-chemical interactions between the filler and the polymer matrix that promote epitaxial crystallization [14,[24][25][26][27].…”