| Summary: | Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2010. === ENGLISH ABSTRACT:
Unsaturated polyesters resins (UPRs) of maleic anhydride (MA), phthalic anhydride (PA) and propylene glycol (PG) were synthesized using the fusion polycondensation process for use in Multi-vesiculated Particles (MVPs). The UPRs were synthesized using different MA:PA mole ratios and process parameters, including heating rates, agitation speed, exotherm rate and maximum processing temperature. Design of Experiments (DoE) software (Design Expert 7) was employed to find the optimum experimental space, i.e. least amount of experiments, but covering all the factors. The variations in the formulation and process parameters had a significant effect on the molecular structure and physical properties of the UPRs. The molecular structure and physical properties of the UPRs was successfully determined using various techniques including viscometry, acid-base titration, Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, Size-Exclusion Chromatography (SEC), Fourier Transform Infrared (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC). Furthermore, the carboxyl and hydroxyl end-group concentrations of the UPRs were determined by derivatization of the groups with trichloroacetyl isocyanate (TAI) and analysis by 1H NMR.
As a second part of the study, the effect of the above-mentioned monomer ratio and process factors of the UPRs, on the properties of the MVPs (produced from the UPRs), was investigated. Results showed that these factors had a significant effect on the particle size and degree of vesiculation of the MVPs. The degree of vesiculation of the MVPs was determined by Scanning Electron Microscopy (SEM). Attempts were also made to determine the relative hardness of the MVPs by AFM and microhardness testing to determine a relationship with UPRs properties (e.g. molecular weight, degree of unsaturation and chain branching). These techniques were however found to be unsuitable due to the physical nature of the MVPs. === AFRIKAANSE OPSOMMING:
Onversadigde poliësters (OPs) van maleïensuuranhidried (MA), fataalsuuranhidried (PA) en propileen glikol (PD) is berei deur die fusie polikondensasie-proses vir gebruik in multi-vesikulerende partikels (MVPs). Die OPs is berei deur gebruik te maak van verskillende MA:PA molverhoudings en reaksie faktore wat verhittingstempo‟s, roerspoed, eksoterm tempo en maksimum reaksie temperatuur, insluit. As gevolg van die groot hoeveelheid faktore is eksperimentontwerp sagteware (Design Expert 7) gebruik om die aantal eksperimente te verminder, maar ook waardevolle afleidings van die data te maak. Die verskille in die formulasie en reaksie faktore het „n merkwaardige effek op die molekulêre struktuur en fisiese eienskappe van die OPs gehad. Hierdie eienskappe is bepaal m.b.v. verskeie tegnieke, naamlik viskometrie, suur-basis titrasie, Proton Kern-Magnetiese Resonansie (1H KMR) spektroskopie, Grootte-Uitsluitings-Chromatografie (SEC), Fourier Transform Infrarooi (FTIR) spektroskopie en Differensiële Skandeerings Kalorimetrie (DSC). Die hidroksiel en karboksielgroep konsentrasies van die OPs is bepaal deur hul reaksie met trichloroasetiel-isosianaat (TAI) gevolg deur 1H KMR analise.
In die tweede deel van hierdie studie is die invloed van bogenoemde faktore op die eienskappe van die MVPs ondersoek. Die resultate het getoon dat hierdie faktore „n merkwaardige effek op die partikel grootte en graad van “vesiculation” van die MVPs gehad het. Die graad van “vesiculation” van die MVPs is bepaal met behulp van Skandeer Elektron Mikroskopie (SEM). Pogings is ook gemaak om die relatiewe hardheid van die MVPs te bepaal deur middel van AFM en Mikro-hardheid toetsing. Dit is gedoen om die verhouding van die OPs eienskappe (molekulêre gewig, graad van onversadigheid en sy-kettings) vas te stel. Hierdie tegnieke is egter ongeskik bevind as gevolg van die inherente fisiese aard van die OPs.
|
|---|
