Maciej Sienkiewicz

Progress in used tyres management in the European Union: A review

The dynamic increase in the manufacture of rubber products, particularly those used in the automobile industry, is responsible for a vast amount of wastes, mostly in the form of used tyres, of which more than 17 million tonnes are produced globally each year. The widely differing chemical compositions and the cross-linked structures of rubber in tyres are the prime reason why they are highly resistant to biodegradation, photochemical decomposition, chemical reagents and high temperatures. The increasing numbers of used tyres therefore constitute a serious threat to the natural environment. The progress made in recent years in the management of polymer wastes has meant that used tyres are starting to be perceived as a potential source of valuable raw materials. The development of studies into their more efficient recovery and recycling, and the European Unions restrictive legal regulations regarding the management of used tyres, have led to solutions enabling this substantial stream of rubber wastes to be converted into energy or new polymer materials. In this article we present the relevant literature describing innovative organizational approaches in the management of used tyres in the European Union member countries and the possible uses of waste tyres as a source of raw materials or alternative fossil fuels.

Fabrication of polyurethane and polyurethane based composite fibres by the electrospinning technique for soft tissue engineering of cardiovascular system.

Electrospinning is a unique technique, which provides forming of polymeric scaffolds for soft tissue engineering, which include tissue scaffolds for soft tissues of the cardiovascular system. Such artificial soft tissues of the cardiovascular system may possess mechanical properties comparable to native vascular tissues. Electrospinning technique gives the opportunity to form fibres with nm- to μm-scale in diameter. The arrangement of obtained fibres and their surface determine the biocompatibility of the scaffolds. Polyurethanes (PUs) are being commonly used as a prosthesis of cardiovascular soft tissues due to their excellent biocompatibility, non-toxicity, elasticity and mechanical properties. PUs also possess fine spinning properties. The combination of a variety of PU properties with an electrospinning technique, conducted at the well tailored conditions, gives unlimited possibilities of forming novel polyurethane materials suitable for soft tissue scaffolds applied in cardiovascular tissue engineering. This paper can help researches to gain more widespread and deeper understanding of designing electrospinable PU materials, which may be used as cardiovascular soft tissue scaffolds. In this paper we focus on reagents used in PU synthesis designed to increase PU biocompatibility (polyols) and biodegradability (isocyanates). We also describe suggested surface modifications of electrospun PUs, and the direct influence of surface wettability on providing enhanced biocompatibility of scaffolds. We indicate a great influence of electrospinning parameters (voltage, flow rate, working distance) and used solvents (mostly DMF, THF and HFIP) on fibre alignment and diameter - what impacts the biocompatibility and hemocompatibility of such electrospun PU scaffolds. Moreover, we present PU modifications with natural polymers with novel approach applied in electrospinning of PU scaffolds. This work may contribute with further developing of novel electrospun PUs, which may be applied as soft tissue scaffolds of the cardiovascular system.

Novel Biodegradable Potato Starch-based Compositions as Candidates in Packaging Industry, Safe for Marine Environment

About 70 % of our planet’s surface is covered by seas and oceans to which even 10 million tons of waste go every year. It makes these places the largest global landfills, containing up to 90 % of plastic waste. In this article we present the results of research on novel starch-based compositions expected to be more safe for the marine environment. For these purpose biopolymers such as, thermoplastic starch (TPS), polylactide (PLA) and poly(vinyl alcohol) (PVA) were reactive extruded and formed into films by high-pressure compressing. Their physical, thermal and mechanical properties were examined. Compositions were tested in seawater collected from the Gulf of Gdansk Baltic Sea. The obtained samples were completely disintegrated after 3 weeks. BOD test in the presence of bacteria pseudomonas augerinosa confirmed biodegradation of prepared compositions. The impact assessment of received materials on the marine environment was also evaluated by degradation tests in the presence of Phaeodactylum tricornutum diatom. Cells growth of Phaeodactylum tricornutum diatoms was only slightly inhibited in the presence of TPS/PLA/PVA compositions.