Blends of high-impact PS(HIPS) and SBS thermoplastic elastomers (Kraton D1101) were studied in relation to recycling. Binary HIPS/SBS elastomer systems containing up to 85% of SBS elastomer were investigated and the blends were characterised by measuring dynamic mechanical properties, creep and recovery and by defining the morphology. An increase in the SBS content in the blend resulted in disappearance of the PS-related brittle type of fracture, while SBS-related ductile fracture appeared. The best mechanical properties were obtained for HIPS/SBS 90/10 blends. Topographic images of polymer blend fracture surfaces were processed using fractal analysis software to obtain the fractal indices of the surfaces. The average fractal index was less than two for the fracture surfaces of the HIPS/SBS blends. The processing and mechanical properties were shown to be in good agreement with the fractal properties of the fracture surfaces even for heterogeneous polymer blend materials. 34 refs.

The possibility of producing secondary materials by blending recycled PE(RPE) from greenhouses and post-consumer ground tyre rubber(GTR) was studied. The blends were prepared in an industrial twin-screw extruder. RPE pellets and GTR powder were fed to the extruder without any other additive. Temperature, processing speed, mixing procedure and composition were changed in order to study the influence of these parameters on the rheological and mechanical properties. The results indicated that the blends exhibited fairly good properties provided that a relatively low concentration of GTR and suitable thermal conditions were adopted. A filler-like effect due to the partial carbonisation of the GTR phase was also shown, especially at the highest processing temperature. 13 refs.

The initial outdoor use of LDPE results in complex chemical, physical and mechanical changes, decreasing material properties of the reclaimed polymer commingled with small amounts of other polymers. An upgrading system was developed which exploited the beneficial chemical changes of the recycled LDPE collected from municipal sources. Analysis of experimental data of melt reprocessing of thermally or photochemically pre-aged LDPE blends with high-impact PS(HIPS) indicated an improvement of impact TS and phase structure after addition of a 1:1 mixture of styrene-butadiene copolymer with EPDM and by restabilisation with N,N'-disubstituted 1,4-phenylene diamine, the latter having a bifunctional character arising from its ability to scavenge both alkyl-peroxy and alkyl radicals. The mechanism of the diamine-mediated compatibilisation process was studied. 12 refs.

Market trends in the tyre industry are briefly reviewed followed by a discussion on the impact of electronics, material technology and regenerated materials and the design of tyres with second lives on the tyre industry.

It is claimed that the plasticisation of structurally inhomogeneous polymers with monomolecular plasticisers is not sufficiently effective because of the difference in the thermodynamic characteristics of the rubber and plasticiser microphases. This article reports on the synthesis of a new plasticiser based on the waste products from alcohol production. The waste products contained a mixture of ethyl, isobutyl and isopentyl alcohols and also chromatographically indeterminate components (3 wt.%). These were subjected to preliminary distillation with the aim of lowering the content of low molec.wt. fractions. The plasticisers were synthesised by the reaction of these waste products with phthalic anhydride in the presence of amphoteric and acidic catalysts. The products obtained were introduced into standard rubber mixes based on SKN-26ASM butadiene-acrylonitrile rubber. The properties of the mixes and vulcanisates containing the new plasticisers and dibutyl phthalate are tabulated. The results indicated that the products obtained are softeners which have similar properties to those of dibutyl phthalate, but which are less expensive. The best properties were found to be achieved in rubber mixes and vulcanisates with a plasticiser synthesised in the presence of an amphoteric catalyst. 4 Refs. (Article translated from Kauchuk i Rezina, No.4, 2004, p.46-7).

This article examines the oxidation resistance of rubber systems comprising vulcanisates with a recycled content. The formulations contain rubbers reclaimed scrap tyres. The oxidation resistance was studied on a manometric unit at a temperature of 150 degrees C and an oxygen pressure of 300 mmHg. The kinetics of oxidation of the products of processing of tyre rubbers are presented with respect to TIRP-0.5, RShT reclaim and butyl reclaim in vulcanisate systems based on SKMS-30ARK butadiene-methylstyrene rubber filled with carbon black. It was suggested that the introduction of elastic fillers retarded the mobility of macromolecular segments of the elastomer in the investigated systems, and consequently the rate of their oxidation. 1 Ref. (Article translated from Kauchuk i Rezina, No.4, 2004, p.45).

A review is presented of current technologies and trends in the field of thermal degradation of scrap tyres. This article discusses the thermal degradation of scrap tyres in gaseous media and in hydrocarbons, and also reviews other methods of thermal degradation. Shortcomings and advantages of pyrolysis systems are discussed, and details are given of plant capacities worldwide. 55 Refs. (Article translated from Kauchuk i Rezina, No.4, 2004, p.26-32).

It is known that the production of fibre fillers with prescribed characteristics of the dispersed composition from waste of rubberised unvulcanised textile materials presents a complex technical problem, since the elastic characteristics of the main components differ greatly. The aim, therefore was to study the influence of the type of failure probability distribution over the length of the fibre on the nature of the dependence of its fractional composition on the processing time of the rubber-fibre composite on milling equipment. In the analysis of the failure of single fibres in a rubber mix flow on milling equipment, it was established that, at the initial moment of in time, the fibres will be equally likely to failure anywhere over their length, and as the average length of the fibres decreases and the viscosity of the mix falls accordingly, fibres will be more likely to fail at their middle. To model the process of change in the size distribution of the fibres with time, it was necessary to switch from the failure of an individual fibre to the equation of the kinetics of grinding. The general integral differential equation of the kinetics of grinding, based on the balance of the mass transfer of the ground particles is presented. The research indicates that in order to improve the effectiveness of fibre grinding, it is necessary to use equipment with a different operating principal from grinding, in particular, cutting equipment, and that, since the processing of rubber-fibre composites on milling equipment is technologically unavoidable, the proposed models, make it possible to estimate the change in the dispersed composition of the composites at different production conversions. (Article translated from Kauchuk i Rezina, No.4, 2004, p.19-22).