A combined raman imaging and transmission electron microscopy study of blends of a deuterated linear polyethylene and a low-density polyethylene

Abstract

Local compositional variations in blends are examined using micro-Raman imaging. Raman images are compared with morphologies detected by transmission electron microscopy (TEM). In isothermally crystallized blends, with morphologies composed of clusters of crystals rich in deuterated linear polyethylene (DLPE) in a matrix of quenched material, the results from both techniques are comparable. These results show that compositional variations of about 30% can be detected by Raman imaging on a scale as small as 2 pm. In rapidly quenched blends exhibiting morphological phase structures on a scale of 1-2 pm in the

Morphology and Crystallization Kinetics of Melt Miscible Polyolefin Blends

“…morphology of surface replicas for quenched LPE and BPE blends by transmission electron microscopy (TEM) was associated with liquid-liquid phase separation [3,4] it was later found by Micro-Raman imaging that the morphology could be explained by differences in nucleation densities and, therefore, crystallization effects on cooling. [5] In addition, research on phase segregation between deuterated LPE and BPE using small-angle neutron scattering (SANS) showed that blends fail to exhibit complete miscibility when branching content is greater than a certain value. [6][7][8] In the case of linear low density polyethylene (LLDPE) copolymers of a heterogeneous composition, phase segregation was proposed to occur in the melt among the species that differ mainly in branching content.…”

Raman Spectroscopy Determination of the Thermoplastic Content within Epoxy Resin-Copolyethersulfone Blends

“…Though not marked in Fig. 7, lower intensities of the PES:PEES bands located around 1145 and 790 cm 21 were often observed with PES: PEES-Cl with a hole of 200 mm . No reproducible peak shift was noticed.…”

“…M icro-Raman spectroscopy allows for a lateral and in-depth resolution on the order of the m icrometer. [16][17][18][19][20][21] Infrared m icroscopy is also used, 23 although its spatial resolution of 8-10 mm constitutes a limiting factor. 19,20 The Raman technique is increasingly used for spatially-resolved characterization of various kinds of phase separated therm oplastic-thermoplastic blends.…”

“…For these blends, examples of qualitative or quantitative Raman measurements of composition or of partial m iscibility are reported, as provided by point-by-point analysis 18,19,[22][23][24] or by imaging or mapping. 17,18,21,25 Only one qualitative study of local com position has been reported for a rubbermodi ed epoxy system. 25 In general, for determining composition quantitatively, either intensities of selected bands, 17,20,21,24,25 curve tting based on the pure components spectra, 17,26 or multivariate analysis are used.…”

“…17,18,21,25 Only one qualitative study of local com position has been reported for a rubbermodi ed epoxy system. 25 In general, for determining composition quantitatively, either intensities of selected bands, 17,20,21,24,25 curve tting based on the pure components spectra, 17,26 or multivariate analysis are used. 19,27,28 This paper presents the development of Raman data calibrations for determining the copolyethersulfone content in epoxy resin-copolyethersulfone blends.…”