Polymer Nanocomposites transmission electron microscopy

Hanley SJ, Giasson J, Revol JF et al (1992) Atomic force microscopy of cellulose microfibrils -comparison with transmission electron-microscopy. Polymer 33 4639 1642 Helbert W, Cavaille JY, Dufresne A (1996a) Thermoplastic nanocomposites filled with wheat straw cellulose whiskers. Part I Processing and mechanical behavior. Polym Compos 17 604-611... 

Recent demands for polymeric materials request them to be multifunctional and high performance. Therefore, the research and development of composite materials have become more important because single-polymeric materials can never satisfy such requests. Especially, nanocomposite materials where nanoscale fillers are incorporated with polymeric materials draw much more attention, which accelerates the development of evaluation techniques that have nanometer-scale resolution." To date, transmission electron microscopy (TEM) has been widely used for this purpose, while the technique never catches mechanical information of such materials in general. The realization of much-higher-performance materials requires the evaluation technique that enables us to investigate morphological and mechanical properties at the same time. AFM must be an appropriate candidate because it has almost comparable resolution with TEM. Furthermore, mechanical properties can be readily obtained by AFM due to the fact that the sharp probe tip attached to soft cantilever directly touches the surface of materials in question. Therefore, many of polymer researchers have started to use this novel technique." In this section, we introduce the results using the method described in Section 21.3.3 on CB-reinforced NR. 

For the comprehension of mechanisms involved in the appearance of novel properties in polymer-emhedded metal nanostructures, their characterization represents the fundamental starting point. The microstructural characterization of nanohllers and nanocomposite materials is performed mainly by transmission electron microscopy (TEM), large-angle X-ray diffraction (XRD), and optical spectroscopy (UV-Vis). These three techniques are very effective in determining particle morphology, crystal structure, composition, and particle size. 

Botana et al. [50] have prepared polymer nanocomposites, based on a bacterial biodegradable thermoplastic polyester, PHB and two commercial montmorillonites [MMT], unmodified and modified by melt-blending technique at 165°C. PHB/Na and PHB/ C30B were characterized by differential scanning calorimetry [DSC], polarized optical microscopy [POM], X-ray diffraction [XRD], transmission electron microscopy [TEM], mechanical properties, and burning behavior. Intercalation/exfoliation observed by TEM and XRD was more pronounced for PHB30B than PHB/Na,... 

Morgan AB, Gilman JW.(2003). Characterization of poly-layered silicate (clay) nanocomposites by transmission electron microscopy and X-ray diffraction a comparative study. J Appl Polym Sci, 87 1329-38. 

In fact, transmission electron microscopy (TEM) observation showed that the size of the dispersed phases increases with increasing filler content in the nanocomposites (Fig. 1.3). It should be noted here that the dispersed phases in the nanocomposites illustrated in Fig. 1.3(b)-(e) are clearly smaller than the untreated Si02 (Fig. 1.3(a)), but they are still much larger than the size of the primary nano-Si02 particles (7mn). Therefore these dispersed phases are actually microcomposite agglomerates consisting of primary particles, grafting polymer, homopolymer, and a certain amount of matrix. 

Transmission electron microscopy (TEM) is the main technique to detect intercalation and exfoliation for polymer-clay nanocomposites. Polyethylene-clay nanocomposites samples with poor (Figure 3.13a) and good (Figure 3.13b) exfoliation are shown in Figure 3.13 [62]. Uniform exfoliation and distribution of clay nanolayers is obtained by in-situ polymerization only when ethylene is polymerized with a metallocene supported on the organoclay in this case. 

Nevertheless, XRD is a useful tool to study the d-spacing of ordered intercalated polymer nanocomposites, it might not be sufficient for exfoliated nanocomposites with no peak. It is generally accepted that transmission electron microscopy (TEM) is the best direct method to demonstrate the dispersion of nanofillers in a polymer matrix. It has been widely used to investigate the dispersion of day in a PET matrix. Eigure 5.4 shows the TEM study of PET/MMT composites [14]. It can be observed that the dispersion of clay in the composites varies due to different processing procedures. It can be either labeled as nanocomposites or conventional... 

Zhao and Shipp synthesized poly(styrene-block-butyl acrylate) (PSBA) by sequential ATRP. BMP was intercalated into the individual layers of clay by ion exchange, and Cu(I)Br complexed by BPMODA was used as the transition metal catalyst After two-step ATRP, PSBA polymer brushes on the clay surface were prepared (Figure 10.2). Their transmission electron microscopy (TEM) result indicated that a mixture of exfoliated and intercalated structures was produced in the nanocomposite. On the surface of clay layers, the block copolymer chains can form nano-sized domains (2 to 5nm), which is much smaller than the size of self-assembly... 

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