Atactic polypropylene (PP) is an amorphous short-chained by-product of isotactic polypropylene (iPP). Due to its enhanced solubility, PP is a suited model polymer for kinetic studies of iPP melt reactions. The maleination of PP via radical grafting at high temperatures was investigated. Since maleic anhydride (MAA) produces discoloring oligomers, PP was grafted with a mixture of MAA and a-methylstyrene (MS). Advantageous is that MS cannot homopolymerize at high temperatures and that MAA and MS tend to copolymerize alternatingly (to colorless products). The kinetics of the grafting process is complicated by a phase separation of PP and [MAA+MS] that is caused by the special attractions between the two monomers. As a result, two grafted PP products are obtained, of which the major is only slightly but the minor is heavily grafted. The latter graft copolymer, which is probably created in the interfaces between phase domains, carries one MAAMS graft per PP back bone chain, approximately with three MAA and five MS units. ZUS AMMENFASSUNG: Ataktisches Polypropylen (PP) ist ein amorphes, kurzkettiges Nebenprodukt des isotaktischen Polypropylens (iPP). Wegen seiner erhohten Loslichkeit ist PP ein gunstiges Modellpolymeres fur Studien der Kinetik von iPP-Schmelzereaktionen. Untersucht wurde die Maleinierung von PP durch radikalische Pfropfung in der Schmelze. Da Maleinsaureanhydrid (MAA) verfiirbende Oligomere bildet, wurde PP mit einer Mischung aus MAA und a-Methylstyrol (MS) gepfropft. Von Vorteil ist, dal3 MS bei hohen Temperaturen nicht homopolymerisieren kann und dal3 MAA und MS praktisch alternierende, farblose Copolymere liefern. Die Kinetik des Pfropfprozesses kompliziert sich durch eine Phasenseparation von PP und [MAA+MS], die bei hoheren Monomerkonzentrationen auftritt und von speziellen Wechselwirkungen zwischen den beiden Monomeren ausgelost wird. Deswegen werden zwei gepfropfte PP-Produkte gebildet, ein wenig gepfropftes Hauptprodukt und ein hochgepfropftes Nebenprodukt. Dieses entsteht vermutlich in den Phasengrenzflachen. Es tragt pro PP-Kette einen MAWS-Ast, der ungefahr aus drei MAA-und funf MS-Bausteinen besteht.
Abstract. Research in Ubiquitous Computing and Ambience Intelligence aims at creating systems able to interact in an intelligent way with the environment, especially the user. To be aware of and to react on the current situation usually a complex set of features describing particular aspects of the environmental state has to be captured and processed. Currently, no standard mechanisms are available to model and reason about complex situations. In this paper, we describe a comprehensive approach for situation-awareness which covers the whole process of context capturing, context abstraction and decision making. Our solution comprises an ontology-based description of the sensing and reasoning environment, the management of sensing devices and reasoning components and the integration of these components into applications for decision making. These technological components are embedded into an conceptual architecture and generic framework which enable an easy and flexible development of situation-aware systems. We illustrate the use of our approach based on a meeting room scenario.
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