The performance of degradable polymer bags

The use of degradable polymers for the collection and composting of organic wastes is explored within this paper. With reference to one trial where the performance of a ‘degradable’ polyethylene based sack for the kerbside collection of organic wastes was investigated. Areas for consideration were the impacts of the degradable polymer on the composting process and the quality of the finished product. This trial also included a comparative study of two different types of ‘degradable’ polymer sacks currently on the European market (polyethylene and starch). A number of quantitative tests were conducted on the different polymers to assess the mechanisms of degradation and how this affected their suitability for the treatment of organic wastes. Provisional results have indicated that the polyethylene (PE) sacks are not degrading as anticipated within open windrow conditions, adversely affecting both the composting process and the quality of the finished compost product. Whilst the degradable starch based sacks appear to actively degrade within open windrow compost conditions.     

Supramolecular architectures featuring stereoisomeric cluster complexes of the [Re6(μ3-Se)8]2+ core

The [Re₆(μ₃-Se)₈]²⁺ core-containing cluster complexes of the general formula [Re₆(μ₃-Se)₈(PEt₃)₄L₂]²⁺ (both trans- and cis-isomers) site-differentiated with inert PEt₃ and functional L ligands that are capable of hydrogen bonding or secondary (with respect to primary coordination with the cluster core) metal-ligand coordination interactions have been prepared. The applications of such stereospecific cluster isomers as building blocks for supramolecular construction have been studied. A great variety of multicluster arrays mediated by intercluster hydrogen bonding or cluster ligand coordination with secondary metal ions have been obtained and structurally characterized. The findings from this research clearly establish the superior utility of these novel building blocks for the creation of structurally sophisticated architectures and possibly functional materials.