Polymer Library

Tyres - February 2015

This month we're looking at tyres, which have been a key part of Smithers Rapra's remit for nearly a hundred years now, with experts based in both the UK and the US working alongside the tyre industry for decades.

Tyres are an essential part of everyday life for many, with most of us relying on road-going vehicles to transport us and/or the products we buy. They're so commonplace that they pose a significant challenge when they reach the end of their useful life with one of the biggest challenges in waste planning today being how to dispose of them in a safe, inexpensive and, above all, sustainable way.

Even though their cheap availability and their bulk should make them an attractive prospect to the recycling industry, this is an under used resource; more than half of all tyres are currently burned for their fuel value. Of the recycled tyre that is used rather than burned, much of the 'crumb' is utilised as a filler material in sports courts. However more innovative uses are being explored with shredded tyre being used as an alternative material in landfill sites where they used as a lightweight backfill in gas venting systems or cover materials. This is proving to be more cost effective for companies as the tyres can be shredded on site instead of transporting in other, more expensive materials.

Why not read some of the latest literature in this area? There is a selection of abstracts from the Polymer Library on this subject below.


These abstracts were highlighted in the February Newsletter and found in the Polymer Library.

Click on the 7-digit accession numbers to find out about ordering a copyright-cleared full text copy of the items shown.

1183977 - Electron tomography provides a direct link between the Payne effect and the inter-particle spacing of rubber composites (OPEN ACCESS - FREE ACCESS TO FULL TEXT)
Rubber-filler composites are a key component in the manufacture of tyres. The filler provides mechanical reinforcement and additional wear resistance to the rubber, but it in turn introduces non-linear mechanical behaviour to the material which most likely arises from interactions between the filler particles, mediated by the rubber matrix. While various studies have been made on the bulk mechanical properties and of the filler network structure (both imaging and by simulations), there presently does not exist any work directly linking filler particle spacing and mechanical properties. Here we show that using STEM tomography, aided by a machine learning image analysis procedure, to measure silica particle spacings provides a direct link between the inter-particle spacing and the reduction in shear modulus as a function of strain (the Payne effect), measured using dynamic mechanical analysis. Simulations of filler network formation using attractive, repulsive and non-interacting potentials were processed using the same method and compared with the experimental data, with the net result being that an attractive inter-particle potential is the most accurate way of modelling styrene-butadiene rubber-silica composite formation. 36 Refs.
Scientific Reports, 2, paper 7389, 2014, pp.7, eISSN: 2045-2322, DOI: 10.1038/srep07389
Staniewicz L; Vaudey T; Degrandcourt C; Couty M; Gaboriaud F; Midgley P

1184219 - Comparative analysis of 14C and TGA techniques for the quantification of the biomass content of end-of-life tires
Thermogravimetric analysis (TGA) and 14C techniques were compared for the determination of the biomass content of end-of-life tyres (ELTs). Samples of different types (of ELTs) were prepared, and the biomass fraction of each sample was measured using the two methods (TGA and 14C). Six reference samples were also prepared with known quantities of natural rubber and stearic acid in order to establish the calibration curve necessary for the thermogravimetric analysis and to verify the accuracy of the results of the 14C analysis. The conclusions were that the 14C technique is the more valid, reliable, and precise method for determining the biomass content of end-of-life tyres, since the results of the 14C tests of the reference samples coincided perfectly with the actual natural rubber and stearic acid content. On the other hand, the results of the thermogravimetric method differed considerably from the known natural rubber content of the reference samples as well as from the results of the 14C technique. This method is therefore not appropriate for use in determining the biomass content of end-of-life tyres. 23 Refs.
Rubber Chemistry and Technology, 87, No.4, Oct.-Dec. 2014, p.664-678, ISSN: 0035-9475, DOI: 10.5254/rct.14.85993
Leticia Saiz-Rodriguez; Bermejo-Munoz J M; Rodriguez-Diaz A; Fernandez-Torres A; Rubinos-Perez A

1183998 - Basic strategy of tire recycling with the emphasis on the tire industry (OPEN ACCESS - FREE ACCESS TO FULL TEXT)
Considering the options for waste rubber - reduction, reuse, recycling, energy recovery and storage in landfills - there is a clear trend towards the renewing of energy. The use of waste tyre as an alternative fuel reduces the amount of old tyres, protect natural resources and increasing energy independence. In many cases, this is a reasonable option. There are lots of sustainable options, extensive use of old tyre that exist today and that will grow (using rubber granules in retreaded asphalt mixed with caoutchouc to manufacture various rubber products, various applications in the construction industry). Based on the analysis method for recycling rubber products, there is a great diversity in the quality and quantity of recycled material. And it is of primary importance for use in new tyres. Methodology production costs optimisation, and quality control require further research and efforts to standardize these processes. 10 Refs.
Annals of Faculty Engineering Hunedoara, 12, No.3, 2014, p.235-238, ISSN: 1584-2665
Stefanovic S; Jevremovic V; Kiss I; Stanojevic D

1184685 - Tyre production up in emerging markets, down in developed ones
Tyre demand depends on vehicle ownership, both for sales of new vehicles and replacement tyre sales. The growth of vehicle density follows an S-curve. Developed markets are at the top of the S-curve, leading to the average vehicle age increasing and scrapping rate falling. Many emerging markets are entering the rapid growth stage, led by China. However, emerging market GDP growth has slowed and the longer term outlook is also for a slower rate of increase than previously expected. North American and EU-27 are the largest net importers of tyres and China and ASEAN are the main suppliers. Imports are largely for the replacement market. The growth of imports into the US has placed pressure on the US tyre industry and another duty on Chinese LV tyre imports is being considered.
Rubber Asia, 28, No.6, Nov.-Dec. 2014, p.106-107
Settles P

1184574 - Goodyear to test self-inflating tyre technology (Short Article)
It is briefly reported that Goodyear is to start testing of its automatic tyre pressure regulator technology on trucking fleets in the next few months. The air maintenance technology (AMT) is a new type of tyre that can monitor and inflate itself to maintain optimal tyre pressure. Goodyear says that AMT will aid in fuel savings, reducing carbon dioxide emissions, improving the lifespan of tyres and removing the need to manually inflate them.
Rubber India, 66, No.12, Dec. 2014, p.62, ISSN: 0035-9491

1184634 - Rubber powder: 2014's new market for tyre recyclers?
While tyre recycling is a business sector that has proven its ability to buck recessionary trends, recyclers face the challenges presented by weakening mature markets and at the same time develop new markets. One solution is to build up a solid market for high quality rubber powders which pay high prices. This reduces dependency on gate fees and enables tyre recyclers to choose the best input material and not compete with thermal uses and tyre recycling competitors.
Tyres and Accessories, Dec. 2014, p.30, ISSN: 0041-4859

1185031 - Recycling ground tire rubber (GTR) scraps as high-impact filler of in situ produced polyketone matrix
A sustainable procedure for recycling powdered rubber coming from scrap tyres (ground tyre rubber (GTR)) is proposed as based on the dispersion in polyketone (PK) matrix, obtained in situ by CO/ethylene copolymerisation. Three types of catalysts are used operative in solvents of different polarities. The catalyst productivity and the hybrids morphology are evaluated and optimized to final composites features. The obtained products are characterised by scanning electron microscopy, atomic force microscopy, and solvent extractions in order to investigate the occurrence and the extent of interactions between PK macromolecular chains and the GTR components; and their effects on the final properties were tested by differential scanning calorimetry, thermogravimetric analysis, and rheological measurements. For comparison purpose, a composite with GTR included into the matrix through blending is prepared. The results evidenced the key role exerted by the catalyst that, when operative in apolar solvent (able to swell the rubber phase), provides composites with good interfacial adhesion and breaking up of the particles with beneficial effects on final properties particularly thermal features and processability. 41 refs.
Polymers for Advanced Technologies, 25, No.9, 2014, p.1060-1068, ISSN: 1042-7147, DOI: 10.1002/pat.3351
Sulcis R; Vizza F; Oberhauser W; Ciardelli F; Spiniello R; Dintcheva N T; Passaglia E


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