The characteristic features of LLDPE polymerization with ZN catalyst are the time drift effect during polymerization and the bending effect when trying to decrease density of the copolymer by adding more comonomer to the polymerization. The time drift in LLDPE polymerization is revealed by a constant decrease of comonomer incorporation during polymerization time. The bending is revealed by difficulties in lowering the density of LLDPE material below the density of 920 kg/ m 3 . With increasing comonomer content during polymerization, the density does not decrease, but the soluble fraction increases. To try to observe if these phenomena are connected, two types of catalysts, SiO 2 supported and precipitated MgCl 2 ZN catalysts, were studied. A short time (10 min) and an extended time (60 min) copolymerization test series where the polymerizations were performed in the presence of a gradually increasing comonomer amount. Both catalysts show a strong bending when density is presented as a function of 1-hexene both in 10-and 60-min polymerization, indicating no connection between time drift and bending. The density, melting point, and crystallinity results all indicate that both catalysts are making similar copolymer material with identical chemical composition distribution.

Video microscopy has been used as an effective tool for fast screening of six different metallocene/MAO supported catalyst samples. The different techniques employed for supporting the metallocene on silica gels can have an influence on the overall catalyst activity and on the activity of single catalyst particles. The kinetics of gas-phase polymerization of ethylene with supported metallocene/MAO catalysts can be modeled by using a simple reaction scheme and neglecting mass and heat transport effects.

UV‐vis spectroscopic study revealed that vinylcyclohexane interaction with zirconocene catalyst is enhanced on light exposure. If oxygen is present it interacts with the catalyst, hindering vinylcyclohexane interaction and consequently lowering the catalyst activity. The catalyst activity can be recovered with light exposure if low O2 concentrations are used since in light the zirconocene‐vinylcyclohexane interaction is favoured over the zirconocene‐O2 interaction. Moreover, 1H NMR studies of the reaction products showed that the structures of the vinylcyclohexane‐based species produced with light irradiation were identical to the species produced in dark. This indicates that light exposure of the catalytic system does not change the reaction mechanism.Absorption spectrum of [(nBuCp)2ZrCl2]/MAO/VCH. (a) reaction in dark, (b) reaction with irradiation, (c) reaction with O2 treatment in dark and (d) reaction with O2 treatment with irradiation.magnified imageAbsorption spectrum of [(nBuCp)2ZrCl2]/MAO/VCH. (a) reaction in dark, (b) reaction with irradiation, (c) reaction with O2 treatment in dark and (d) reaction with O2 treatment with irradiation.

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Museology is a discipline still establishing itself. It can currently be studied in five Finnish universities. Museology came to Finland as early as 1969 when Secretary of Museum Affairs Jorma Heinonen from the Finnish Museums Association gave his first course in museology. It took more than a decade before museology gained status as a university subject in 1983, and about the same amount of time for the first professorship in 1998. Little by little, museology has strengthened its position in Finnish universities, but what has happened on the labour market at the same time?

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