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Highly resolved transmission infrared microscopy in polymer science

“…It is important to point out that the synchrotron beam is highly polarised, and the relative band intensities in the spectra of anisotropic polymeric systems will depend on the orientation of the sample with respect to the electric vector of the beam. This sensitivity has already been demonstrated within both a-and b-spherulites for one of the band relationships shown to be characteristic of the polymorphic content [91]. If we record a series of spectra at fixed distance, r from the centre, or nucleus, of a given spherulite and at variable angle, h, Fig.…”

“…Vectra A950 is a thermotropic copolyester of 73% hydroxybenzoic acid and 27% hydroxynaphthoic acid. Full details of the sample preparation technique are given elsewhere [79]. The model composites were given specific thermal histories in a Mettler FP82HT (Mettler-Toledo) microscope hot stage, after erasing any prior thermal history in the matrix [80].…”

“…The second most common is the trigonal or b-form, which can be generated by temperature gradients or shear conditions, or can be activated by nucleating agents or surfaces [90]. Recently we have shown that subtle differences in the IR spectra of the a-and b-forms of iPP can allow us to differentiate between crystalline polymorphs [86,91], including the microscopic discrimination between individual spherulites. Fig.…”

“…The darker negatively birefringent a-spherulites surround it. Using the 1330 cm À1 /1168 cm À1 band relationship, previously described as sensitive to a-/ b-polymorphs [91], we can construct a high resolution IR false-colour contour map of the area marked A on the microphotograph, Fig. 5a, and can easily differentiate between the two crystal forms.…”

“…Examples include biological or biomedical systems [44][45][46][47][48][49][50][51][52][53], food science [54][55][56][57], geology and geochemistry [58][59][60][61], electrochemistry and surface science [62][63][64][65], high pressure studies [66,67], industrial research and forensics [68][69][70][71][72][73], and time-resolved spectroscopy [59,74]. However, to date only a few examples for the study of synthetic polymers have appeared in the literature [75][76][77][78][79].…”