The development of a novel technique for AFM thermal analysis of individual phases in polymer mixtures after separation and identification via LC-FTIR

De Goede, E. (Elana) (2004-03)

Thesis (MSc)--Stellenbosch University, 2004.

Thesis

ENGLISH ABSTRACT: In the ongomg search for better and faster ways to characterize complex polymer systems, it is often necessary to couple different analytical techniques in order to obtain information on more than one distributed property. In this study, the coupling of chromatography and spectroscopy to atomic force microscopy (AFM) was attempted for the first time, and thus the term "LC-FTIR-AFM" was coined. This new hyphenated technique combines the separation power of liquid chromatography (LC) and the ability of infrared spectroscopy (IR) to identify almost any organic compound, with the AFM's ability to be used for thermal analysis of individual phases in polymer mixtures. The first two steps of this new technique comprise (i) the separation of compounds in a mixture via gradient polymer elution chromatography (GPEC) and (ii) the identification of each compound by means of LC-FTIR analysis. In the final step, LC-FTIR analysis is coupled to AFM through the use of the LC-FTIR interface. A number of polymer mixtures were analysed by means of the novel technique that was developed, in order to establish its validity and value as a characterization technique of the future. The influence of fllm thickness and molar mass on the thermal parameters of individual components in mixtures, measured by this technique, were also investigated. This technique adds a new dimension to conventional thermal analysis methods, since it allows the thermal transitions of individual polymer phases in multiphase polymers to be resolved directly after separation and identification.

AFRIKAANSE OPSOMMING: In die voortdurende soektog na beter en vinniger maniere om komplekse polimeersisteme te karakteriseer, is dit soms nodig om verskillende analitiese tegnieke met mekaar te koppel ten einde inligting aangaande twee of meer verspreide eienskappe te bekom. Gedurende hierdie studie is daar gepoog om chromatografie en spektroskopie met atoominteraksie-mikroskopie (atomic force microscopy, AFM) te koppel. Gevolglik het die term "LC-FTIR-AFM" ontstaan. Hierdie nuwe koppelingstegniek kombineer die kragtige skeidingspotensiaal van vloeistofchromatografie en die vermoë van infrarooispektroskopie om byna enige organiese verbinding positief te identifiseer, met die atoominteraksie-mikroskoop se potensiaal om as 'n termiese analise metode vir individuele fases in polimeermengsels te dien. Die eerste twee stappe van die tegniek behels (i) die skeiding van verbindings in 'n mengsel deur middel van gradient-hoë-druk-vloeistofchromatografie en (ii) die identifisering van afsonderlike verbindings deur vloeistofchromatografie gekoppel aan infrarooispektroskopie. Gedurende die finale stap word vloeistofchromatografie en infrarooispektroskopie aan die atoominteraksie-mikroskoop gekoppel deur gebruik te maak van die LC-FTIR koppelingsapparaat. 'n Aantal polimeermengsels is geanaliseer deur die nuwe tegniek hierbo beskryf, ten einde die geldigheid en waarde daarvan as 'n analitiese metode vir die toekoms vas te stel. Die invloed van film diktes en molekulêre massa op die termiese oorgange van individuele komponente in mengsels, soos gemeet deur hierdie metode, is ook ondersoek. Hierdie tegniek voeg 'n nuwe dimensie tot konvensionele termiese analise metodes deurdat dit die bepaling van termiese oorgange van individuele polimeerfases III multifase polimere, direk na afloop van skeiding en identifikasie moontlik maak.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/53766
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