A homopolimerização de etileno foi investigada utilizando o catalisador (nBuCp)2ZrCl2 suportado em sílicas modificadas quimicamente com diferentes espaçadores. Dentre eles, foram utilizados Me3SiCl, Me2HSiCl, Ph3SiCl, polimetilhidrossiloxano (PMHS), GeCl4, SnCl4 ou PbCl2. As interações organossilano-sílica, zirconoceno-silanos suportados e zirconoceno suportadosilanos suportados foram estudadas através do método teórico ICONC. Os teores de metal foram determinados por Espectrometria de retroespalhamento Rutherford (RBS), enquanto a modificação química da superfície da sílica foi monitorado por Espectroscopia molecular no infravermelho com Transformada de Fourier (FT-IR) ou Espectroscopia molecular no infravermelho de refletância difusa (DRIFTS). As espécies zirconocenas superficiais foram investigadas por Espectroscopia de raio-X (XPS). A morfologia dos sistemas catalíticos e polímeros obtidos foram caracterizados por Microscopia eletrônica de varredura (SEM) e a distribuição de metal do sistema contendo PMHS foi estudada por Microssonda eletrônica (EPMA). Estes sistemas catalíticos produziram polietilenos com estreita polidispersidade e alta atividade catalítica utilizando metilaluminoxano como cocatalisador. Os efeitos da modificação química da sílica na performance catalítica são apresentados e discutidos. / The homopolymerization of ethylene was investigated using the catalysts of (nBuCp)2ZrCl2 supported on chemically modified silica with different spacers. The spacers used were Me3SiCl, Me2HSiCl, Ph3SiCl, polymethylhydrosiloxane (PMHS), GeCl4, SnCl4 or PbCl2. The organosilanes-silica, zirconocene-supported silanes and supported zirconocene-supported silanes interactions were studied by ICONC method. The metal contents were determined by Rutherford backscattering spectrometry (RBS), while the chemical modification of the silica surface was monitored by Fourier transform infrared spectroscopy (FT-IR) or Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The zirconocene surface species were investigated by X-ray spectroscopy (XPS). The morphology of these catalytic systems and polymers were evaluated by Scanning electron microscopy (SEM) and the metal distribution for the PMHS systems was studied by Electron microprobe analysis (EPMA). These catalytic systems produced polyethylene with a narrow molecular weight distribution and high catalyst activities using methylaluminoxane as co-catalyst. The effects of the chemical modification of the silica on the catalyst performance are presented and discussed.

Les polyolefins représentent plus de la moitié de la production mondiale de plastiques et 80% de ces polymères sont produits avec des catalyseurs hétérogènes de type Phillips, Ziegler-Natta et métallocènes. En effet, un bon fonctionnement des unités du fait d'un faible encrassement du réacteur ou des autres équipements de l'unité, une activité stable, une bonne morphologie particulaire des polymères et un une densité apparente élevée sont obtenus en utilisant des catalyseurs hétérogènes. D'un autre côté l'hétérogénéisation d'un catalyseur s'accompagne d'une diminution de l'activité et d'un élargissement de la distribution de masses molaires qui est parfois non désiré car cela peut influencer l'aptitude à la transformation et les propriétés mécaniques des polyoléfines. Plusieurs explications ont été avancées dans la littérature afin d'expliquer l'effet de l'immobilisation d'un catalyseur ce qui inclut la résistance diffusionnelle au transport du (des) (co)- monomère(s) vers le site actif et la modification du comportement du catalyseur conduisant à plusieurs espèces actives. Néanmoins l'ensemble de ces explications est en connexion avec les propriétés physiques du support (tailles des particules, surface spécifique, volume poreux, diamètre des pores…) car ce dernier peut en effet impacter la nature des espèces actives ainsi que leur dispersion et la diffusion des monomères. Les catalyseurs métallocène sont considérés comme mono-site et tout changement dans la nature du site actif au cours de son immobilisation et toute résistance au transfert de matière peuvent être détectés par un élargissement de la distribution des masses molaires. Le présent travail a pour objet d'étudier les effets des propriétés physiques des catalyseurs métallocènes supportés sur silice concernant la cinétique de polymérisation et les caractéristiques des polymères produits. Pour cela le traitement thermique de la silice a été fixé à 600°C afin de contrôler son état de surface tandis que la quantité de catalyseur supporté a été gardée autant que possible constante. De plus les protocoles de polymérisation en phases suspension et gaz ont été fixés après avoir évalué différentes conditions de polymérisation et différents composés alkylaluminium. Cette étude systématique a permis d'attribuer les différences observées en termes de cinétique de réaction des catalyseurs métallocènes à la différence des paramètres physiques des silices utilisées comme support et par conséquent à la résistance diffusionnelle au transport du (des) (co)-monomère(s) au(x) site(s) actif(s) durant la polymérisation / Polyolefins account for more than half of the world’s plastic production and about 80% of these polyolefins are commercially produced with heterogeneous olefin polymerization catalysts such as Phillips, Ziegler-Natta and metallocenes. Trouble-free plant operation due to low fouling of the reactor or other plant equipment, relatively stable catalytic activity, good polymer morphology and high polymer bulk densities can be achieved by employing heterogeneous olefin polymerization catalysts. On the other hand, heterogenization of the olefin polymerization catalysts lead to drastic reduction in their activities and broadening of the polymer molar mass distribution which is undesirable in some cases because it can influence the processability and mechanical properties of the polyolefin grade. Various explanations have been proposed in the open literature to explain these effects of catalyst immobilization which mainly include existence of diffusion resistance to (co)-monomer(s) transport at the active sites during polymerization and the change of the active site(s) behavior due to immobilization leading to multiple site types on the final supported catalyst. Nevertheless, both of these explanations have a connection with the physical properties (e.g., particle size, surface area, pore volume, pore diameter etc.) of the support because the support can impact the nature of the final active species formed on it, dispersion of the active species throughout the support particles and, last but not the least, the intraparticle diffusion of (co)-monomer(s) during polymerization. Metallocenes are considered as single-site catalysts and any changes in the nature of the active site(s) upon their immobilization on a support or during the course of polymerization due to mass transfer resistance can be detected from the broadening of polyolefin molar mass distribution. Therefore, the present work is an attempt to study the effects of physical properties of silica supported metallocenes on their ethylene polymerization kinetics as well as on the morphology of the produced polyethylene. For this purpose, the surface chemistry of the used commercial silica supports was fixed by dehyroxylating all of them at 600 °C, whereas, the final metal loadings of the supported catalysts were nearly kept constant by preparing them under identical conditions. Furthermore, slurry and gas phase polymerization protocols along with the used aluminum alkyl scavenger (which can also induce chemical effects on the catalytic behavior of supported metallocenes) were also fixed by testing different polymerization protocols and scavengers. Such systematic study has allowed us to attribute the observed differences in the reaction kinetics of the supported metallocenes, explicitly, to the differences in the physical parameters of the silica supports and, consequently, to the existence of diffusion resistance to (co) monomer(s) transport at the active site(s) during the course of polymerization

Die Darstellung von gespannten ansa-Komplexen verschiedener Übergangsmetall-Sandwichverbindungen gelingt durch Umsetzung von dimetallierten Metallocenvorstufen mit den entsprechenden Elementdiahlogeniden. Die Ringspannung in diesen Systemen kann für eine ausgeprägte Folgereaktivität (Ringöffnungsreaktionen, ROP, Diborierung, Bis(silylierung), etc.) ausgenutzt werden. Kristallstrukturanalysen verschiedener Borol-Derivate belegen die hohe Lewis-Azidität des Borzentrums sowie den antiaromatischen Charakter dieser Verbindungsklasse. / The synthesis of strained [n]metalloarenophanes of several transition-metal sandwich complexes has been achieved by salt elimination reactions of dimetalated metallocene precursors with the appropriate element dihalides. The molecular ring strain in these sytems is accompanied by an enhanced reactivity (ring-opening reactions, ROP, diboration, bis(silylation), etc.). X-ray diffraction studies of several borole derivatives have proven the extraordinarily high Lewis acidity of the boron center, as well as the antiaromatic character of these heterocycles.

<p> The foaming process has received increased attention by the rotational molding industry in recent years. The use of metallocene catalyzed polyethylenes for producing a cellular structure is a new development in rotational molding. The objective of this work was to investigate the effects of different chemical blowing agents, resin properties and processing conditions on the structure of foamed metallocene polyethylene and obtain a fundamental understanding of the parameters governing the foam structure and part properties.</p> <p> An experimental study was conducted to produce metallocene polyethylene foams in dry-blending-based rotational foam molding. The physical and cell structure properties of the final foamed parts were examined. The critical processing parameters that optimize the foam structure have been identified through adjustments to the molding conditions.</p> <p> The foaming performance of exothermic and endothermic chemical blowing agents were examined and it was revealed that selecting an appropriate chemical blowing agent was crucial as the foam structure depends significantly on the properties of the blowing agent. Exothermic blowing agents resulted in greater foam density reduction compared to endothermic blowing agents.</p> <p> The effect of rheological properties on the foaming process and foam properties was also examined. Rotomolding experiments were performed in monolayer and skin-foam moldings. Observations indicated that the final foam properties were profoundly influenced by the rheological properties of the polymer materials. There was a good correlation between the foam properties produced in both monolayer and two layer moldings. It was discovered that polymer materials with higher extensional viscosity could provide a promising foaming performance at different processing conditions.</p> <p> The effect of the surface tension of the polymer materials was investigated. It was found that type of reaction of the blowing agent (exothermic/endothermic) and composition of gas generated determine whether the surface tension of the resin contributes to the trend of changes in foam properties.</p> / Thesis / Master of Applied Science (MASc)

This work is concerned with a better understanding of the influences that sparse long-chain branching has on the rheological and processing behavior of commercial metallocene polyethylene (mPE) resins. In order to clarify these influences, a series of six commercial polyethylenes was investigated. Four of these resins are mPE resins having varying degrees of long-chain branching and narrow molecular weight distribution. The remaining two resins are deemed controls and include a highly branched low-density polyethylene and a linear low-density polyethylene. Together, the effects of long-chain branching are considered with respect to the shear and extensional rheological properties, the melt fracture behavior, and the ability to accurately predict the flow through an abrupt 4:1 contraction geometry. The effects that sparse long-chain branching (M_branch > M_c) has on the shear and extensional rheological properties are analyzed in two separate treatments. The first focuses on the shear rheological properties of linear, sparsely branched, and highly branched PE systems. By employing a time-molecular weight superposition principle, the effects of molecular weight on the shear rheological properties are factored out. The results show that as little as 0.6 LCB/10⁴ carbons (<1 LCB/molecule) significantly increases the zero-shear viscosity, reduces the onset of shear-thinning behavior, and increases elasticity at low deformation rates when compared to linear materials of equivalent molecular weight. Conversely, a high degree of long-chain branching ultimately reduces the zero-shear viscosity. The second treatment focuses on the relationship between long-chain branching and extensional strain-hardening behavior. In this study, the McLeish-Larson molecular constitutive model is employed to relate long-chain branching to rheological behavior. The results show that extensional strain hardening arises from the presence of LCB in polyethylene resins, and that the frequency of branching in sparsely branched metallocene polyethylenes dictates the degree of strain hardening. This observation for the metallocene polyethylenes agrees well with the proposed mechanism for polymerization. The presence of long-chain branching profoundly alters the melt fracture behavior of commercial polyethylene resins. Results obtained from a sparsely branched metallocene polyethylene show that as few as one long-chain branch per two molecules was found to mitigate oscillatory slip-stick fracture often observed in linear polyethylenes. Furthermore, the presence and severity of gross melt fracture was found to increase with long-chain branching content. These indirect effects were correlated to an early onset of shear-thinning behavior and extensional strain hardening, respectively. Conversely, linear resins exhibiting a delayed onset of shear-thinning behavior and extensional strain softening were found to manifest pronounced slip-stick fracture and less severe gross melt fracture. The occurrence of surface melt fracture appeared to correlate best with the degree of shear thinning arising from both molecular weight distribution and long-chain branching. The ability to predict the flow behavior of long-chain branched and linear polyethylene resins was also investigated. Using the benchmark 4:1 planar contraction geometry, pressure profile measurements and predictions were obtained for a linear and branched polyethylene. Two sets of finite element method (FEM) predictions were obtained using a viscoelastic Phan-Thien/Tanner (PTT) model and an inelastic Generalized Newtonian Fluid (GNF) model. The results show that the predicted profiles for the linear PE resin were consistently more accurate than those of the branched PE resin, all of which were within 15% of the measured vales. Furthermore, the differences in the predictions provided by the two constitutive models was found to vary by less than 5% over the range of numerical simulations obtained. In the case of the branched PE resin, this range was very narrow due to loss of convergence. It was determined that the small differences between the PTT and GNF predictions were the result of the small contraction ratio utilized and the long relaxation behavior of the branched PE resin, which obscured the influence of extensional strain hardening on the pressure predictions. Hence, it was expected that numerical simulations of the 4:1 planar contraction flow for the mildly strain hardening metallocene polyethylenes would not be fruitful. / Ph. D.

Les travaux décrits dans ce manuscrit ont trait à l’élaboration de supports organiques fonctionnels à base de polyisoprène pour la catalyse de polymérisation de l’éthylène par les métallocène et post-métallocène. Une série de polyisoprènes ω-OH et de copolymères à blocs de type polyisoprène-b-poly(méthacrylate de méthyle) et polyisoprène-b-poly(oxyde d’éthylène) de masse molaire variable a été réalisée par polymérisation anionique vivante. L’auto-assemblage dans l’heptane de ces (co)polymères conduit à la formation d’agrégats micellaires stables qui permettent l’immobilisation des systèmes catalytiques via des interactions créées entre le bloc polaire du support et l’activateur aluminique, le plus souvent le méthylaluminoxane. La polymérisation de l’éthylène en présence de ces supports organiques conduit, sans diminution d’activité catalytique, à la formation de particules de polyéthylène de taille micrométrique. Selon la même méthodologie, des polyisoprènes portant à leur extrémité une fonction borate ont été synthétisés et avantageusement utilisés comme supports activateurs de métallocènes pré-alkylés. Dans ce cas, des particules de polyéthylène de taille millimétrique ont pu être obtenues. / The work described in this manuscript relates the development of organic functional supports based on polyisoprene for the catalysis of ethylene polymerization by metallocenes and post-metallocenes. Polyisoprenes ω-OH and block copolymers [polyisoprene-b-poly(methyl methacrylate) and polyisoprene-b-poly(ethylene oxide)] with different molecular weights were synthesized by living anionic polymerization. Self-assembly in heptane of (co)polymers leads to the formation of stable micellar aggregates allowing the immobilization of catalytic systems created thanks to interactions between the polar block of the support and the aluminic activator, the most often methylaluminoxane. The ethylene polymerization in the presence of organic support drives, without loss of catalytic activity, to the formation of polyethylene particles of micrometer size. Using the same methodology, polyisoprenes bearing at their ends a borate function have been synthesized and advantageously used as supports activators of pre-alkylated metallocenes. In this case, polyethylene particles with a millimeter size have been obtained.

Résumé confidentiel / Résumé confidentiel

The research goal of this work was dedicated to improvement of the properties and enhancement of the application potential of commodity polymer based on polyolefins by choosing different synthesis routes to create new structures and materials. More precisely, the presented study explores different aspects of metallocene and post-metallocene catalyzed olefin polymerization leading to synthesis of novel copolymers and nanocomposites. The first part of this thesis deals with controlled polymerization of α-olefins catalyzed by post-metallocenes. Bis(phenoxyamine) zirconium complexes with [ONNO]-type ligands bearing cumyl (bPA-c) and 1-adamantyl (bPA-a) ortho-substituents were applied. For the polymerization catalyzed by bPA catalyst quasi-living kinetic character is proposed. The bPA catalyst was applied for synthesis of block copolymers by employing the strategy of sequential monomer addition. The blocky structure of the copolymer was successfully achieved and confirmed by NMR techniques. Moreover, the monomodal distribution of molar mass in SEC chromatogram confirmed the absence of homopolymers. In the second part of the work new defined comb-like copolymers (CLC) having a poly(10-undecene-1-ol) (PUol) backbone and densely grafted poly(ε-caprolactone) (PCL) side chains are presented. These copolymers were synthesized in two steps by means of metallocene polymerization followed by ring opening polymerization. Copolymers with varied and adjustable graft length (PCL segments) were synthesized. It was proved that the melting and crystallization temperatures of the CLC correlate with the PCL side chain length, i.e. longer chains result in higher Tm and Tc,o values. The melting enthalpy was found to be asymptotically dependent on the length of PCL side chains. The bulk morphology of the comb-like copolymers is proposed to be lamellar as judged from the TEM micrographs. The third part of the thesis is focused on the synthesis of polypropylene nanocomposites via in situ polymerization. Thereby, organomodified aluminumphosphate with kanemite-type layered structure (AlPO-kan) has been used as novel filler. Melt compounding composites were prepared for comparison purposes to evaluate the influence of in situ synthesis on the dispersion quality of the filler in polymer matrix. Melt compounding of neat AlPO-kan with PP did not lead to formation of nanocomposites. TEM images show macro-composites with the lamellar solid remaining agglomerated. On the contrary, in situ polymerization of propene yielded materials with exfoliated nanocomposite morphology. In XRD, diffractions of the AlPO-kan pilling of layers are not detectable. It can be concluded that the primary existing layers are delaminated. Very fine distribution of the filler in the polypropylene matrix has been impressively demonstrated by TEM.

Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2006. / This study concerns the investigation of the isomerization of different metallocene catalysts in solution, and the effects thereof on the microstructure of polypropylenes prepared with these catalysts. Two C2 symmetric ansa metallocenes, ethylene-bis(indenyl) zirconium dichloride (EI) and dimethylsilyl-bis(2-methyl benzoindenyl) zirconium dichloride (MBI) were exposed, in solution, to both sunlight and UV radiation. The rac-meso isomerization of these catalysts were followed by 1H NMR spectroscopy. The reaching of a photostationary state is described, as well as the effect of isomerization of these catalysts in solution on the polymerization of propylene. Results show that metallocene structure has an effect on the isomerization rate and photostationary state. Results also show that the wavelength of light plays a role in the isomerization process. Effects on stereochemistry and molecular weight of the formed polymer as well as the catalyst activity is described and discussed. In addition the effect of activating the catalysts with MAO before exposure to light is discussed.

Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The properties of polymer nanocomposites depend greatly on the chemistry of the polymer matrices, the nature of the nanofillers, and the way in which they are prepared. Understanding the synthesis–structure–property relationship of nanocomposites is vital for the development of advanced polymer nanocomposites with enhanced mechanical strength, stiffness and toughness for structural engineering applications. To this end, the primary aim of this study was to determine the impact that the preparation methods have on the properties of PP/filler nanocomposites, with specific focus on the in situ polymerization of propylene via the methylaluminoxane (MAO) activated metallocene catalyst technique. Two different fillers (Silica and Calcium carbonate) were used as support for the metallocene catalysts. Different supporting methodologies for the synthesis of the supported catalyst were examined. A C2 symmetric metallocene catalyst ansa dimethylsilylbis(2-methyl benzoindenyl) zirconium dichloride (MBI) was used in this study. The catalyst systems were then evaluated for propylene polymerization. The early observation shows that a direct adsorption of the metallocene onto the filler has a diminishing effect on the catalyst productivity and the fillers had to be treated with MAO in order to avoid catalyst deactivation by the filler surface. Due to the low productivity of the supported active species, the presence of soluble catalyst active species, besides the supported active species is required in the synthesis of PP nanocomposites via in situ polymerizations. The syntheses of PP nanocomposites were carried out via in situ polymerization in which different quantities of MAO treated fillers were reacted with pre-activated catalyst solution. The effect of the addition of MAO-filler on the polymerization kinetics and consequently on PP matrix microstructure was investigated. Changes in the in situ polymerization kinetics, compared to kinetics of homogeneous polymerization, were observed. Therefore, the microstructure of the polymer matrix was also influenced by the presence of nanofillers in the polymerization media. The influence of the different synthesis methods on the performance of the nanocomposites was investigated using melt-mixed PP/filler nanocomposites obtained using PP homopolymer. The dispersed phase morphologies of the different nanocomposites were investigated by transmission electron microscopy (TEM). Results show that PP nanocomposites with improved filler dispersion were achieved by in situ polymerization compared to melt-mixed nanocomposites. The influence of the synthesis method on the crystallization behaviour of PP nanocomposites was also investigated. It was found that, for the in situ prepared nanocomposites the tacticity of the PP matrix plays the major role in determining the degree of crystallinity. Results also show that when nanocomposites with comparable PP matrices are compared, the overall crystallization rate of the in situ polymerized nanocomposites is higher than that of the melt mixed nanocomposites. The mechanical properties of in situ polymerized PP and melt mixed PP nanocomposite were also investigated and compared. Due to improved nanoparticle dispersion in the PP matrix, in situ polymerized nanocomposites show enhanced mechanical properties, especially tensile and impact properties, compared to pure PP and melt mixed prepared nanocomposites when a PP matrix of equivalent microstructure was used. Finally, the melt compounding method was further investigated using different fillers and commercial PP as a matrix. The effect of filler type, size and applied surface coating on the flow and mechanical properties of PP nanocomposites was studied. The aim of this part of this study is to obtain a good trade-off between the processability and the mechanical properties and to gain insight into the cause of the emergence of different properties for nanocomposites prepared by melt compounding. / AFRIKAANSE OPSOMMING: Die eienskappe van polimeer nanokomposiete hang grotendeels af van die chemie van die polimeer matriks, die wese van die nano-vullers, en die manier waarop hierdie materiale berei word. Om die sintese-struktuureienskap verwantskap te verstaan is noodsaaklik vir die ontwikkeling van gevorderde nanokomposiete met beter meganiese eienskappe, styfheid en taaiheid vir strukturele ingenieurstoepassings Die primêre doelstelling van hierdie studie was dus om die impak van voorbereidingsmetodes op die eienskappe van PP/vuller nanokomposiete te bestudeer, met spesifieke fokus op die in-situ polimerisasie van propileen met metiel alumoksaan-geativeerde metalloseen kataliste. Twee verskillende vullers (silika en kalsium karbonaat) is gebruik as ondersteuning vir die metalloseen kataliste. Verskillende metodiek is gebruik om die ondersteunde kataliste te berei. ‘n C2 simmetriese metalloseen katalis ansa-dimetielsiliel(2-metiel bensoindeniel) sirkonium dichloride (MBI) is in die studie gebruik. Die katalissisteme is daarna evalueer vir propileen polimerisasie. Daar is oorspronklik vasgestel dat direkte adsorpsie van die metalloseen op die vuller ‘n negatiewe effek op die katalis aktiwiteit gehad het, en dat die vuller oppervlak eers met MAO behandel moes word om deaktivering van die katalis deur die vuller-oppervlak te vermy. As gevolg van die lae aktiwiteit van die ondersteunde aktiwe katalisspesies, is die teenwoordigheid van opgeloste aktiewe katalis nodig vir die voorbereiding van PP nanokomposiete via in situ polimerisasie-reaksies. Die sintese van PP nanokomposiete is uitgevoer deur in –situ polimersiasie waartydens verskillende hoeveelhede MAO-behandelde vullers gereageer is met vooraf-geaktiveerde katalis oplossings. Die effek van die byvoeging van MAO-vuller op die polimerisasie-kinetika en gevolglik op die PP matriks mikrostruktuur is ondersoek. Dit is gevind dat die mikrostruktuur van die polimeer-matriks beinvloed word deur die teenwoordigheid van nanovullers in die polimerisasie-medium. Die invloed van verskillende bereidingsmetodes op die eienskappe van die nanokomposiete is ondersoek deur smelt-vermengde PP/vuller nanokomposiete te maak. Die dispersie-fase morfologie van verskillende nanokomposiete is ondersoek deur transmissie elektron mikroskopie (TEM). Resultate wys dat PP nanokomposiete met verbeterde vuller-dispersie berkry is deur in situ polimerisasie in vergelyking met die smelt-vermengde materiale. Die effek van die sintese-metode op die kristallisasie van die PP nanokomposiete is ook ondersoek. Daar is gevind dat, vir die in situ bereide nanokomposiete, die taktisiteit van die PP matriks die grootste rol speel in die bepaling van die persentasie kristalliniteit. Resultate het ook gewys dat, wanneer nanokomposiete met soortgelyke PP matrikse vergelyk word met die in situ nanokomposiete, die laasgenoemde se tempo van kristallisasie hoer is as vir die smelt-vermengde nanokomposiete. Die meganiese eienskappe van die in situ bereide en smelt-vermengde PP nanokomposiete is ook ondersoek en vergelyk. As gevolg van verbeterde nano-partikel dispersie in die PP matriks, het die in situ bereide nanokomposiete beter meganiese eienskappe openbaar, in vergelyking met die smelt-vermenge nanokomposiete, veral trek- en slagsterkte. . Laastens is die smelt-vermengings metode verder ondersoek deur gebruik te maak van verskillende vullers en kommersiële PP as matriks. Die effek van die tipe vuller, die grootte en die oppervlakbedekking van die vullerpartikels op die vloei en meganiese eienskappe van die PP nanokomposiete is ondersoek. Die doel van hierdie studie was om ‘n balans te kry tussen prosesseerbaarheid en meganiese eienskappe en om insig te verkry oor die verskille in eienskappe wat openbaar word wanneer smeltvermengde nanokomposiete bereie word.