聚合物中空间分布、纵向各层分布、厚度、反应过程检测方案

HORIBAExplore the futureAutomotive Test Systems 1 Process & Environmental 1 Medical 1 Semiconductor Scientific Raman Spectroscopy Applied to Polymer Science Vincent Larat， Application Scientist - HORIBA Jobin Yvon SAS， 231 rue de Lille， Villeneuve d'Ascq， France Raman Spectroscopy is a scattering technique probing the vibrational modes of molecules and crystals.Raman signatures provide information about the chemical nature and the crystalline structure of samples.This characterisation method is fast， non-destructive and does not require any particular sample preparation. HighRaman Selectivity for PolymersIdentification_ Raman spectroscopy can be used for the identificationof chemical species； its high spectral resolution allowsclosely related chemical substances to be distinguished.Furthermore， this method is sensitive to macromolecularstructure： chains orientation， crystallinity properties can beinvestigated by Raman spectroscopy. Fast and easy polymer identification can be achieved usingRaman spectroscopy. This example shows the spectra of the mainpolymer families： all of them have characteristic features enablingstraightforward identification of unknown material. Raman for Polymerization ReactionMonitoring- As Raman spectroscopy is chemically selective， it can beused to monitor over time chemical reactions， such aspolymerization. Whether it is on lab scale or on industrialscale， a wide set of probes and measurement heads areavailable to fit your setup. The results of a co-polymerization reaction of 90% vinyl di-chloride(VC2) and 10% methyl acrylate (ACM) is shown below， highlightingthe different conversion rates of the 2 monomers. Concentration profiles may result from the monitoring of peak. intensities -such as C=C bonding of thereactants- but in more complex matrices，chemometrics may be applied for moreaccurate results. High Spatial Resolution RamanMicroscopy of Polymers Confocal Raman microscopy allows sub-micronfeatures and objects analysis and leads to high spatialdiscrimination within heterogeneous samples， not onlyat the surface but also in depth， in the case of laminarsamples or inclusions. The analysis of polymer laminates requires high spatialresolutive systems， as the thicknesses of the layers includedin the sample may measure only few micrometers. Analysis of a laminate cross-section In this example， a commercial plastic bag isanalyzed on its cross section.All layers -includingthe ones having less than 3pm thick- are mappedand identified. Xm) Depth profile analysis of a laminate Instead of measuring the laminate on its cross section， confocal Raman microspectroscopy enablesanalyzing in depth. This multilayer sample comprising PA and PE layers was measured in depth using animmersion oil objective， to estimate the thicknesses of the different layers. Distribution of Constituants_ Hyperspectral Raman imaging provides information on the chemical and structural nature， as well asspatial distribution of elements within the crystal. Depending on the grain size and level of heterogeneity， optimal mapping step and laser spot sizescan be adjusted from sub-micron to hundredsof microns to prevent the analyst frommissing mineral constituents while optimizingmapping speed. Fast mapping option may beused to speed up the whole imaging process. The chemical image above shows the distributionof additives - fillers -within the polyethylenematrix of a white plastic bag sample. Both calcite(CaCOs) and dolomite (CaMg(CO3)2 particles offew micrometers are identified and localized in thesample.