One of the current problems faced by mankind is the problem of safe disposal of waste rubber. Statistics show that the number of waste tires is continuously increasing at a very rapid rate. Since rubber materials do not decompose easily (due to their crosslinked structure), they end up being a serious ???environmental problem???. An intuitive solution to prevent the accumulation of the scrap tires is to continuously reuse them. A new patented reclamation method was discovered in our laboratory, which makes use of a twin screw extruder (TSE) in order to produce reclaimed rubber (referred as devulcanized rubber (DR) from here on) of very high quality. Also, this method has proven to be more economical than other commercial reclaiming methods. Products made solely from a reclaimed material face challenges from those made by virgin materials because of relatively poor properties. However, the striking advantage of using reclaimed rubbers is the cost reduction. Hence, it is important to work on establishing methods by which these reclaimed rubbers could be efficiently used and incorporated into present day products. The deterioration of properties could be minimized by blending them with varying amounts of other materials. A possibility in this direction is manufacturing of thermoplastic vulcanizates (TPVs) using reclaimed rubber and general purpose thermoplastics. In accordance with this idea, the focus of this research is to prepare DR and polypropylene (PP) based TPVs. DR is unique as the rubber itself consists of two phases- one phase consisting of uncrosslinked (including devulcanized rubber molecules), and the other phase consisting of crosslinked (un-devulcanized) rubber. These un-devulcanized crumbs act as stress concentrators because they do not break-up easily, and lead to poor physical properties. Hence, this project tries to find out ways to increase the interfacial adhesion between the rubber and PP by using reactive and non-reactive techniques. Preliminary experiments were carried out in a batch mixer to compare DR and rubber crumb (CR). DR based TPVs showed better properties than CR based TPVs, however, the properties were not useful for commercial applications. Sulphur based dynamic vulcanization was studied in a batch mixer and found to be not effective in improving the properties of DR based blends. On the other hand, DCP/ sulphur based curing system was found to show significant improvement in properties. Therefore, DCP/sulphur based curing package was studied in detail on the blends consisting of DR and PP. The optimum ratio of DCP/sulphur was found to vary depending on the ratio of DR/PP. A hypothesis regarding the mechanism of DCP/sulphur curing has been proposed, which seem to correlate well with the experimental results observed. Additionally, it was determined that DR prepared from tire rubber (DRT) performed better than DR prepared from waste EPDM (DRE) for the curing system used. Accordingly, experiments on a TSE were carried out using DRT and a combination of compatibilizing resins and curatives. This combination showed a drastic improvement in blends properties and once again the optimum ratio of compatibilizing resins seemed to depend on the ratio of DRT/PP. As a result of the work, successful strategies based on reactive compatibilization techniques were developed in order to prepare useful TPVs having up to 70% DR. A series of compatibilization techniques has been evaluated using design of experiments and various characterization techniques such as mechanical tests, scanning electron microscopy, thermal analysis and crosslink density measurements. This led to the development of a formulation, which could improve the blend properties significantly. A tensile strength of around 10 MPa and an elongation-at-break of 150-180 % could be achieved for devulcanized rubber (70%) based TPVs, which has broadened the scope for its commercial applications. In addition to that, the process was established on a TSE that has enabled a continuous and steady production of these TPVs with reasonable throughputs.

Konstgräsplaner kan beaktas som en betydande utsläppskälla av mikroplaster. Fyllnadsmaterialet som används på konstgräsplaner kallas granulat och går under definitionen mikroplast. De som används främst på den svenska marknaden är SBR, TPE, EPDM och R-EPDM. Granulatet sprids främst via dagvattnet från konstgräsplaner som då riskerar att hamna i närliggande vattendrag. Tidigare studier har påvisat att granulatet kan urlaka toxiska ämnen som riskerar att förorena vattendragen. Vattenlevande organismer kan misstolka små partiklar som föda, vilket kan ge konsekvenser som bland annat förstoppning och svält. Ämnena som kan urlaka tillhör samlingsnamnet miljögifter och är stabila, toxiska, reproduktionsstörande och ackumulerande. Syftet med denna studie är att ge en beskrivning av vilka fyllnadsmaterial som används på konstgräsplaner i Gävle och undersöka hur dessa partiklar kan spridas samt identifiera åtgärdsförslag för att minska spridningen. Syftet är också att redovisa konstgräsplanernas dagvattenutlopp och vattendragens status för att redogöra för den potentiella miljöpåverkan som granulatet kan ge upphov till. Metoderna som använts i arbetet är litteraturstudie, personlig kommunikation, fältobservationer, kartsystem och figurer samt vattenprov.   Gavlefastigheter äger fem konstgräsplaner i Gävle kommun, vilka är Träffen IP, Gavlevallen, Nynäs IP, Sörby IP och Andersberg. På dessa planer används SBR- TPE- och R-EPDM-granulat. På planområdet förekommer dagvattenbrunnar och granulatet kan spridas till dessa genom ytavrinning vid höga regnflöden, snöplogning och smältvatten samt att spelarna får med sig partiklarna från planen. De flesta planer har dräneringssystem kopplat till dagvattenledningar som kan sprida urlakande ämnen till vattendrag. Dagvattenledningarna har utlopp i Testeboån, Bäckebrobäcken, Gavleån och Hemlingbybäcken. Granulatets fysikaliska egenskaper är en betydande roll om partikeln sedimenterar till botten eller om den kan transporteras med vattendraget. De konstgräsplaner som främst är i behov av åtgärder för att minska spridningen av granulat är Sörby, Anderberg och Nynäs.   Vattendragens statusklassning uppnår ej god kemisk status och ämnen som förekommer i förhöjda halter varierar beroende på vattendrag. Enligt tidigare studier kan flera av dessa ämnen urlaka från granulatet, vilket innebär att det finns en risk för ett tillskott av dessa ämnen om spridning sker. / Artificial turfs have been shown to be a significant source of microplastics. The filling material used on artificial turf is called granules and are under the definition microplastic. There are different kinds of granules on the Swedish market, these are SBR, TPE, EPDM and R-EPDM. The granules spread mainly through stormwater from artificial turf, which may then end up in nearby streams. Previous studies have shown that the granules can release toxic substances that risk contaminating the water. Aquatic organisms can misinterpret microscopic particles as food, which can cause consequences such as constipation and starvation. The substances that may leach from the granules belongs to the collective name environmental toxins and are stable, toxic, reproductive and accumulative.   The purpose of this study is to provide a description of the filling material that are used in artificial turfs in Gävle, investigate how these granules can spread and then identify suggestions to reduce the spread. The purpose is also to present the artificial turf's stormwateroutlets and water status to describe the potential environmental impact that the granulate may cause. The methods used in this work are literature studies, personal communication, field observations, map systems and figures and water samples.   Gavlefastigheter owns five artificial turfs in the municipality of Gävle which are Träffen IP, Gavlevallen, Nynäs IP, Sörby IP and Andersberg. These turfs use SBR- TPE and R-EPDM granules. There are open water wells on every turf area and granules can spread to these by surface water at intensive rain, snow plowing and meltwater and with the players when they leave the turf. Most turfs have drainage systems connected to stormwater pipelines that can spread leachable substances to water. The water pipelines have outlets in Testeboriver, Bäckebrostream, Gavleriver and Hemlingbystream. The physical properties of the granules have a significant effect if the particle sinks to the bottom or if it is transported along with the water. The artificial turfs that are primarily in need of taking actions to reduce the spread of granules are Sörby, Anderberg and Nynäs.   The waters do not achieve good chemical status and substances that occur at high concentrations varies depending on the kind of water. According to previous studies, several of these substances may leach from the granules which means that there is a risk of a contribution of these substances if spreading occurs.