Applications of polymer microscopy

Spherulites as small as 1 im in diameter have been reported they cannot be resolved by conventional polarized microscopy. Small-angle light scattering is 

The lamellar structure is best studied using TEM. Let us take polyethylene. Two methods of preparation are commonly used staining with chlorosulphonic acid/uranyl acetate and etching with permanganic acid. 

The location of the sections should be random with respect to the centres of the spherulites (axialites). From simple geometrical considerations, it can be deduced that the average distance between the section and the spherulite centre should be R/ i, where R is the radius of the spherulites. It is well established that [010] is parallel to the radius of a mature spherulite. Hence, crystal lamellae which appear sharp are predominantly viewed along [010] 40% of the surface is within a 20° angle from [010] and 60% within a 30° angle from [010]. 

Linear polyethylene displays relatively straight and long crystal lamellae. The amorphous interlayers are generally very thin. Occasional roof-ridged lamellae are found. The number of lamellae per stack is high. Branched polyethylene 

It has been argued on several occasions that the crystal thickness values as obtained by TEM on chlorosulphonated specimens are too low. Hill, Bradshaw and Chevili (1992) showed that the sections may shrink when the sections are 

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The application of election Microscopy technique to polymer analysis involves sufficient extension beyond the ordinary techniques. Some salient points are discussed here. 

For the development, production, and application of polymer latices the determination of the size distribution and the analysis of the chemical composition and heterogeneity of the latex particles are important. The size distribution can be determined rapidly by ultracentrifugation, electron microscopy or light scattering > but for the analysis of the... 

In contrast to ED, the great success of electron microscopic techniques in the elucidation of structural features of biological materials is widely recognised. Particularly important is the determination of the shapes and sizes of virus particles and DNA fibres (Chapter 12). Applications of electron microscopy in the field of technology include the study of phosphated metal surfaces (Chapter 12.7), implants of dental and biomedical phosphate materials (Chapter 12.14), and determination of particle size and polymer structure of other P compounds. 

Poled PVDF films show fenoelectiic behavior clearly demonstrating the polarization reversal in the dielectric Itysteresis curve (Nalwa 1995). Locally created domains ate reported (Giithner and Dransfeld 1992) in scanning force microscopy observations in PVDF. Typical values of the spontaneous polarization are 8-10 X 10 Ccm and of the coercive field 50-100 kVmm . For the material properties see Table 7.17. Uniaxially drawn films are much mote anisotropic in piezoelectric properties. The piezoelectric coefficients are higher than e.g. for quartz crystals, but lower than for PZT ceramics. It is highly desirable to improve the piezoelectric coefficients for the possible applications of polymers. 

Branching in polymer chains has been studied by various methods sedimentation velocity, light scattering, and viscosity measurements in two solvents. The application of acoustic microscopy to a study of stilfhess and density in polymers has been described by Tucker and Wilson. ... 

Natural and synthetic textile fibers were among the earliest materials studied by electron microscopy. Guthrie [1] and Stoves [2] described the techniques and applications of fiber microscopy to industrial practice. Somewhat later, evidence was provided for an oriented microfibrillar texture in polymer fibers [3]. X-ray diffraction suggested an arrangement of fine structures about 50 nm long and 5 nm wide in semicrystalline fibers [4, 5]. Peterlin [6, 7] observed the formation of fibrils and microfibrils by the deformation and transformation of spheru-lites using various nucroscopy techniques. 

Yao Nan and Kung Eugene. Polymer characterization using electron microscopes. In Industrial applications of electron microscopy, Zhigang R Li (ed.). Chapter 13, pp. 357-386. New York Marcel Dekker, 2003. 

Hifumi et al. [34] applied ultra-fine platinum particles protected by poly(Me acrylate-co-N-vinyl-2-pyrrolidone) to inununological detection of metham-phetamine (MA). The polymer-protected ultra-fine particles chemically boimd anti-methamphetamine monoclonal antibody to their surfaces. The antibody-fixed particles behaved like an antibody in the inununoreaction, making it possible to detect the MA to a concentration of ca. 10 ng/mL. Uda et al described a similar application of polymer-protected ultra-fine platinum particles to the im-mvmological detection of human serum albumin [35]. Tamai et al. [36] showed that ultra-fine metal particles could be immobilized on fine copolymer particles that were produced by reducing copolymer particles-metal ion complexes. Transmission electron microscopy and X-ray diffraction were used to confirm that ultra-fine noble metal particles with a diameter below 10 run were formed and uniformly immobilized on the surface of copolymer particles. 

RJ Young, RJ Day. Application of Raman microscopy to the analysis of high modulus polymer fibres and composites. Br Polym J 21 17-21, 1989. 

Only a few typical examples of all the possible applications of light microscopy to the structural examination of plastics have been mentioned here for a comprehensive review, cfr. ref. [53], Hemsley [33] has described microscopy of polymer surfaces by a variety of techniques. A number of books and general references give details on the various applications of light microscopy [17,42,54,55],... 

Polymers containing UV stabilisers or fluorescent additives are an obvious target for UV microscopy, but the potential range of applications is much wider, in that UV absorbers or fluorescers can be selectively bound to specific chemical entities in the polymer or will preferentially interact with, or dissolve in, parts of the structure. A variety of applications of the UV microscope to studies of polymers has been reported (Table 5.15). Many applications of UV microscopy require quantitative analysis. 

Fluorescence microscopy has also been employed largely for 2D surface imaging. Scanning confocal fluorescence microscopy has been applied to the investigation of subsurface morphology of foams. The general knowledge on the applications of fluorescence microscopy for polymers is rather limited. 

Recent reviews report many applications of Raman microscopy to polymers [488,592,593]. Applications of Raman microspectroscopy to materials science [594] and art and forensic science [595] were also reviewed. 

Figures 8 and 9 show applications of NMR microscopy in the rheological investigation of complex viscoelastic fluids. In Figure 8 comparative velocity and diffusion profiles are shown across the diameter of a 700 p,m diameter capillary though which is pumped a solution of high-molecular-mass polymer undergoing laminar flow. The velocity profile is distinctly non-Poiseuille, consistent with shear thinning, while the polymer self-diffusion coefficients exhibit a dramatic enhancement once the shear rate (the velocity gradient) exceeds a characteristic value. This value corresponds to the slowest relaxation rate of the molecule where rj is the so-...

Applications Applications of UV/VIS spectrophotometry can be found in the areas of extraction monitoring and control, migration and blooming, polymer impregnation, in-polymer analysis, polymer melts, polymer-bound additives, purity determinations, colour body analysis and microscopy. Most samples measured with UV/VIS spectroscopy are in solution. However, in comparison to IR spectroscopy additive analysis in the UV/VIS range plays only a minor role as only a limited class of compounds exhibits specific absorption bands in the UV range with an intensity proportional to the additive concentration. Characteristic UV absorption bands of various common polymer additives are given in Scheirs [24],... 

Applications The general applications of XRD comprise routine phase identification, quantitative analysis, compositional studies of crystalline solid compounds, texture and residual stress analysis, high-and low-temperature studies, low-angle analysis, films, etc. Single-crystal X-ray diffraction has been used for detailed structural analysis of many pure polymer additives (antioxidants, flame retardants, plasticisers, fillers, pigments and dyes, etc.) and for conformational analysis. A variety of analytical techniques are used to identify and classify different crystal polymorphs, notably XRD, microscopy, DSC, FTIR and NIRS. A comprehensive review of the analytical techniques employed for the analysis of polymorphs has been compiled [324]. The Rietveld method has been used to model a mineral-filled PPS compound [325]. 

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