Zugl.: Dresden, Techn. Univ., Diss., 2005

Universiẗat, Diss., 2002--Freiburg (Breisgau).

Techn. Hochsch., Diss., 2002--Aachen.

University, Diss., 2004--Hamburg.

V textilním průmyslu je v dnešní době veliká konkurence. Každá novinka může znamenat velký zisk. Tato diplomová práce se bude zabývat aplikací termochromních přísad (látka reagující na teplotu změnou své barvy) do polymerní matrice, konkrétně polypropylenu, a jeho další zpracování u výrobce technického polotovaru - výroba vláken. Po výrobě vzorků bude provedeno jejich testování. Porovnají se vlastnosti polypropylenu s a bez termochromních přísad a zhodnotí se, nakolik tyto přísady ovlivňují vlastnosti polypropylenu. Ze získaných výsledků se stanoví možnost využití termochromních přísad v textilním průmyslu.

Heterogeneous Ziegler-Natta catalysts are responsible for most of the industrial production of polyethylene and polypropylene. A unique feature of these catalysts is the presence of more than one active site type, leading to the production of polyolefins with broad distributions of molecular weight (MWD), chemical composition (CCD) and stereoregularity. These distributions influence strongly the mechanical and rheological properties of polyolefins and are ultimately responsible for their performance and final applications. The inherent complexity of multiple-site-type heterogeneous Ziegler-Natta catalysts, where mass and heat transfer limitations are combined with a rather complex chemistry of site activation in the presence of internal and external donors, plus other phenomena such as comonomer rate enhancement, hydrogen effects, and poisoning, makes the fundamental study of these systems a very challenging proposition. In this research project, new mathematical models for the steady-state and dynamic simulation of propylene polymerization with Ziegler-Natta heterogeneous catalysts have been developed. Two different modeling techniques were compared (population balances/method of moments and Monte Carlo simulation) and a new mechanistic step (site transformation by electron donors) were simulated for the first time. Finally, polypropylene tacticity sequence length distributions were also simulated. The model techniques showed a good agreement in terms of polymer properties such as molecular weights and tacticity distribution. Furthermore, the Monte Carlo simulation technique allowed us to have the full molecular weight and tacticity distributions. As a result, the 13C NMR analytical technique was simulated and predicted.

If a plastic material is used as a print bearer there are a need of a special surface treatment to get agod and durable printing. The most used surface treatment technique for the moment is coronatreatment. This kind of treatment has unfortunately showed not to be so durable in the long term.Plasma treatment which in this case uses different kind of gases in the treatment of polypropyleneis shown as a more effective treatment in this project. When the plasma treated surface has beenprinted is the good quality last much longer and the adhesion between the ink and the surface isremained. To test this adhesion is for the moment a standard used (ASTM D3359). This standardhas appeared unstable and dependent at many different factors, which gives a big variation in thetest results. Because of this has new test methods been carried out to give a more even and morereliable result in the test of the adhesion.

Heterogeneous Ziegler-Natta catalysts are responsible for most of the industrial production of polyethylene and polypropylene. A unique feature of these catalysts is the presence of more than one active site type, leading to the production of polyolefins with broad distributions of molecular weight (MWD), chemical composition (CCD) and stereoregularity. These distributions influence strongly the mechanical and rheological properties of polyolefins and are ultimately responsible for their performance and final applications. The inherent complexity of multiple-site-type heterogeneous Ziegler-Natta catalysts, where mass and heat transfer limitations are combined with a rather complex chemistry of site activation in the presence of internal and external donors, plus other phenomena such as comonomer rate enhancement, hydrogen effects, and poisoning, makes the fundamental study of these systems a very challenging proposition. In this research project, new mathematical models for the steady-state and dynamic simulation of propylene polymerization with Ziegler-Natta heterogeneous catalysts have been developed. Two different modeling techniques were compared (population balances/method of moments and Monte Carlo simulation) and a new mechanistic step (site transformation by electron donors) were simulated for the first time. Finally, polypropylene tacticity sequence length distributions were also simulated. The model techniques showed a good agreement in terms of polymer properties such as molecular weights and tacticity distribution. Furthermore, the Monte Carlo simulation technique allowed us to have the full molecular weight and tacticity distributions. As a result, the 13C NMR analytical technique was simulated and predicted.

Die Arbeit behandelt die Entwicklung eines Verfahrens zur Herstellung von naturfaserverstärktem Langfasergranulat. Ausgehend von den speziellen Eigenschaften von Naturfasern und dem Stand der Technik bei der Verarbeitung von naturfaserverstärkten Thermoplasten wird ein neues Verfahrensprinzip für die Herstellung von Langfasergranulat mit Naturfaserverstärkung konzipiert. Die konstruktive Auslegung der einzelnen Anlagenkomponenten wird theoretisch betrachtet und durch geeignete Modelle beschrieben. Mit der praktischen Umsetzung des Verfahrensprinzips werden wesentliche Zusammenhänge zwischen den Prozessbedingungen und den Granulateigenschaften analysiert. Die resultierenden Eigenschaften von Natur-Langfasergranulaten werden phänomenologisch charakterisiert und mit konventionellen Langfasergranulaten verglichen. Unter Anwendung bekannter Modellvorstellungen zu den mechanischen Eigenschaften von faserverstärkten Kunststoffen wird das theoretische Eigenschaftspotenzial von diskontinuierlich langfaserverstärkten Naturfaserverbunden berechnet und durch experimentelle Untersuchungen an flachsfaserverstärktem Polypropylen verifiziert.Abschließend erfolgt die Darstellung der experimentell ermittelten mechanischen, morphologischen und rheologischen Eigenschaften der im Spritzgießverfahren hergestellten Verbunde aus Natur-Langfasergranulaten.

Zugl.: Bayreuth, Univ., Diss., 2009