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Enzyme ? mediated polymer synthesis

100%

Rokicki G.

Biotechnologia

2005

nr 2

103-124

Enzyme ? mediated polymer synthesis in non-natural environments has significantly expanded in scope and impact over the past 10 years. This review focuses on a rapidly expanding research activity where in vitro enzyme catalysis is used for the synthesis of polyesters, polycarbonates, polyphenols, vinyl polymers, as well as natural and artificial oligosaccharides like cellulose, amylose, xylan, and chitin. The inclination to use enzymes for polymer synthesis has been fuelled by a desire to carry out these reactions in the absence of heavy metal-based catalysts, under mild conditions and with high selectivity. The aspects of this work that include enzyme-catalyzed step-growth polycondensation, chain-growth ring-opening polymerizations, oxidation polymerization and corresponding transesterification of macromolecular substrates are discussed. The polymerization utilizes mainly hydrolases and oxidoreductases as catalysts. Characteristic features of enzymatic polymerizations are also discussed.

Fuel fractions obtained in the recycling of plastics

51%

Sokołowski J. , Rokicki G. , Marczewski M. , Krajewska J.

Polish Journal of Chemical Technology

2007

tom 9

nr 3

46-50

The decomposition of mixtures of polystyrene, polyethylene, and motor oil was studied at 470 - 510°C in a flow-through setup supplied with a fluidized bed reactor and a cascade of receivers. The aim of the work was to determine the role of the fluidized bed in the reactor, in the process of degradation of plastics in the cases where it was only a carrier of heat for the endothermal process of pyrolysis or it was both a carrier of heat and a catalytic bed for the process. The effect of the catalyst granulation and of the method of the organization of work in the reactor on the yield of the process and on the composition of the products obtained, was also studied.In the cases where Al2 O3 of granulation 0.2 mm was used as a fluidized bed catalyst the liquid products of the decomposition of the polymers contained mainly alkyl-aromatic derivatives of styrene, benzene and alkane hydrocarbons. If nano-Al2 O3 was used as a catalyst and it was introduced into the reactor with a stream of raw materials, the obtained products were solids, composed mostly of styrene and alkene hydrocarbons.