Crystallization in Polymer Nanocomposites

Abstract

Over the past decade, polymer nanocomposites have been a topic of great interest to research groups in both pure and applied materials science [1 -4] . These nanocomposites are two -phase materials wherein a fi ller with at least one dimension in the range of 1 to 100 nm is dispersed in the polymer matrix. Various nanofi llers such as carbon nanotube s ( CNT s), inorganic nanoparticles, or layered silicates such as clay are used. These nanocomposites show remarkable property improvements as compared to virgin polymers; moreover, this occurs at very low fi ller loadings when compared to conventional microcomposites. The properties of these nanocomposites are dependent on the morphology generated during their processing. In the case of semi -crystalline polymers, this is more crucial as the crystallization of polymers takes place during processing. A knowledge of the crystallization process, and the effect of these nanofi llers on the crystallization behavior of polymer nanocomposites, is therefore imperative to acquire an understanding of structure -property relationships in polymer nanocomposites.Crystallization in polymers has been the subject of great academic interest, as polymers are known to exhibit a variety of structures at various length scales, such as the unit -cell, lamella, and spherulites. The crystallization of polymers results in different morphologies, depending on the crystallization conditions and the presence of other components. The presence of a second phase either a polymer or a low -molecular -weight compound or inorganic fi ller has a profound effect on the crystallization of the polymer. In nanocomposites, the dimensions of the second phase are close to the chain dimensions, and a number of studies have attempted to elucidate the effect of nanosized fi llers on the crystallization kinetics, the crystalline morphology, and the crystalline forms of polymers. In this chapter, a brief review is presented of recent investigations into the effects of nanofi llers on various aspects of crystallization, such as isothermal crystallization, nonisothermal crystallization, spherulitic growth, and polymorphism.

Assessment of cellular toxicity of TiO2nanoparticles for cardiac tissue engineering applications

“…Polymer nanocomposites are a rapidly evolving class of relatively new materials finding applications in soft tissue engineering (TE) (Jog 2006). Advantages include a significant improvement in mechanical properties (El-Fray and Boccaccini 2005;Liu et al 2008) as well as enhanced cellular adhesion (Webster and Smith 2005;Bacakova et al 2007) and higher cytocompatibility than composites containing conventional micrometer particles (Webster et al 2003;Webster and Smith 2005;Mei et al 2007).…”

Polymer Spherulitic Growth Kinetics Mediated by Nanoparticle Assemblies

“…It is well established that the incorporation of nanoparticles (NPs) into polymer matrices can have a large impact on their mechanical, electrical, optical, and thermal properties. − Semicrystalline polymers comprise approximately 70% of commercial polymers, and their properties sensitively depend on their morphology . An easy way to modify this morphology is to add NPs to the polymer, and therefore, over the last few decades, there has been extensive research on this topic, for example, crystalline morphologies, ultimate crystallinity, rates of nucleation and growth, and interaction mechanisms and how they are affected by NP addition. − Zhao et al , found that a critically important quantity in this situation is the mobility of the NPs relative to the spherulitic growth rates. For large enough spherulitic growth rates, the NPs are trapped and engulfed by the growing polymer spherulites.…”

Supernucleation Dominates Lignin/Poly(ethylene oxide) Crystallization Kinetics

“…Industries have been shifting into sustainable alternatives, and the use of biodegradable/biocompatible materials has been the focus of various groups. − Poly­(ethylene oxide) (PEO) is a biocompatible, semicrystalline polymer used in various applications: solid electrolytes, , for drug delivery, , in biomedical scaffolds, and for polymer fabrication. , An easy way to create robustly advanced materials from such a polymer is through nanoparticle (NP) incorporation. , Since PEO is a semicrystalline polymer with a high degree of crystallinity, the corresponding nanocomposite and blend properties are highly affected by changes in the crystallization kinetics and the final semicrystalline PEO morphology. Thus, many studies have focused on understanding how NP addition affects crystallization kinetics − this topic is precisely the focus of this paper.…”