Reclaim Rubber Research Articles

Rheological analysis of bitumen modified by reclaim rubber pyrolytic oil residue

Heavy fraction pyrolytic oil of waste tire reclaim rubber vacuum pyrolysed at 600 °C (HR6) was produced. Then, it was considered as a rheological modifier for road bitumen. Addition of HR6 to bitumen was increased penetration and decreased softening point. Rutting temperature and temperature susceptibility of bitumen was improved using this rheological modifier. The bitumen containing 5% of HR6 showed optimum level in comparison to different concentration was used. Ductility of modified bitumen has significantly increased. Rheological behavior of modified samples was studied through static and dynamic tests, which showed good improvement in complex viscosity, modulus and damping factor; respectively. Very good low temperature flexibility observed by bending beam rheometer (BBR) test proposing flexible behavior in winter. Moreover, the aging by rolling thin film oven (RTFO) and storage stability was studied and reported.

폐타이어 재생 고무가 카본 블랙이 충전된 천연 고무/부타디엔 고무 복합재의 물리기계적, 열적 특성에 미치는 영향

Combinations of natural rubber (NR), butadiene rubber (BR), and reclaim rubber (RR) were prepared with a view to producing low-cost re-treading materials. It was found that cure time and scorch time decreased with the increase in the reclaim content. Only a small reduction in the properties was observed in almost all systems upon the addition of 30 phr of reclaim rubber. Systems with good abrasion resistance and tensile strength were obtained. High tensile values of 22.8 and 20.1 MPa were able to obtain for the NR-rich system. Tear strength can be enhanced by the addition of reclaim rubber. Elongation at break was higher for all the systems even after adding 30 phr of RR. Modulus and compression set values were increased with RR loading. The thermal behavior and activation energy of NR/BR/RR blends were improved by the addition of RR. The phase morphology of the blends was studied using a scanning electron microscope.

Devulcanisation and reclaiming of tires and rubber by physical and chemical processes: A review

Abstract Since their creation, tires have been constantly improved to fulfil the numerous applications they have been employed in. Although tires consisted of simple rubber bands in the late 20th century, nowadays tires are a highly more complex piece of technology. Due to this more complex structure induced by the presence of other components (like metals and textiles) and a wide variety of polymers used in tire manufacturing, recycling and reclaiming processes are constantly more difficult. Taking into account the global tire demand as well as the amount of rubber involved and their end-of-life fate is mandatory for a sustainable development. The aim of this review is to present and explore physical and chemical processes that are employed in order to recycle tire and reclaim rubber. Well settled techniques such as mechanical, thermo-mechanical, cryo-mechanical grinding and sulfide processes are presented as well as more sustainable technologies such as ionic liquid, eutectic solvents and microwave and catalysis.

Reclaiming of waste guayule natural rubber vulcanizate—reclaim rubber for green tire applications: An approach for sustainable development

This article illustrates the reclaiming of guayule natural rubber (GNR) vulcanizate by bis[3-(triethoxysilyl)propyl] tetrasulfide (TESPT), and as-grown reclaim rubber facilitates the silica dispersion in GNR product application without adding any coupling agent. This article deals with the performance evaluation of silica-filled revulcanizates with promising application in green tire. The extent of reclaiming was monitored through the measurement of sol content, cross-link density, Mooney viscosity, and degree of reclaiming. The differential scanning calorimetry study was carried out to evaluate the fraction of immobilized polymer chains and its dependence on cross-link density of the vulcanizates. The Fourier transform infrared study and also sulfur analysis independently indicate the attachment of the fragmented TESPT with the polymer chain and cross-link bonds. The study of mechanical properties clearly shows that in revulcanized GNR, the optimum property is achieved when reclaiming time is set for 40 min. The effect of reclaiming time on dynamic mechanical behavior such as storage modulus and loss tangent was studied. The scanning electron microscopy studies show the coherency and homogeneity of silica-filled revulcanize rubber with reclaiming time.

Determination of silica content and its dispersion in NR‐PBR‐RR ternary blends/ nanocomposites by digital image analysis of SEM images

To study the silica content and its dispersion behavior in natural rubber (NR)‐polybutadiene rubber (PBR)‐reclaim rubber (RR)/ nanocomposites, scanning electron microscopy (SEM) images was used by image processing technique. A suitable algorithm was proposed to determine the silica percentage of the nanocomposites. Based on proposed algorithm, image analysis was carried out to present quantitative and qualitative measure of size distribution of silica (filler) agglomerates in the polymer nanocomposites. On the basis of stack based region detection algorithm, various sizes of silica particles was detected and 2D image was reconstructed through 10 different colors for 10 types of regions. This article also dealt with various aspects of the polymers such as filler‐filler interaction, agglomerate detection, and dispersion of filler agglomerates through image analysis of their SEM micrographs. POLYM. COMPOS., 38:2080–2089, 2017. © 2015 Society of Plastics Engineers

The Influence of Reverse Logistics on Reclaiming – A Case of Recycling Used Truck Tires

When using recovered raw materials to manufacture recycled products, the key to quality is securing reliable quantities of clean, homogenous materials. Naturally the implementation of such recycling system requires an appropriate reverse logistics network. The search for new ways to recycle rubber waste including used tires focusing quality is the aim of many studies worldwide. The recycling of used tire and make use of that into new tires has been slow to develop; because of technological and economic limitations resulting from differences in chemistry and fabrication methods used to produce the tires. This paper focus on producing reclaimed rubber from used tires with consistent quality characteristics. A case study was conducted in a used truck tires recycling plant employed single screw extruder reclaimator process. Traditional feed of recovered materials using existing reverse logistics networks and organized feed of recovered materials with a proposed network involved in the used truck tires has been analyzed in the paper focusing the quality characteristics of reclaimed rubber made out of used tires though experimental research work. The influence of organized buffing powder feed on various quality characteristics of the devulcanized material were studied and presented by using MATLAB. It has been observed that the devulcanization process in reclaimator process depends on the temperature and residence time acting on buffing powder in which the organized feeding of recovered material plays a vital role. Obtained products possess consistent quality comparable to that of reclaim rubber available on the market.

Effect of Sol-Gel-Derived Nano-silica on the Properties of Natural Rubber-Poly Butadiene Rubber-Reclaim Rubber Ternary Blends/Silica Nanocomposites

Silica incorporation into natural rubber (NR)-polybutadiene rubber (PBR)-reclaim rubber (RR) ternary blend system was carried out by sol-gel technique at different temperatures. The effect of RR on silica reinforcement was studied for NR-PBR-RR blend systems. The physicochemical properties of sol-gel vulcanizates indicates that the reinforcing efficiency of the nanocomposites increases with increasing RR content. Sol-gel vulcanizates prepared at 50°C shows superior mechanical properties than others. The amount of silica incorporated by sol-gel technique was determined through thermogravimetry analysis, which indicates the increasing trend of thermal stability with silica content. SEM studies indicate the coherency and homogeneity in the NR-PBR-RR/SiO 2 nanocomposites.

Application of NR Gloves Reclaim: Cure and Mechanical Properties of NR/Reclaim Rubber Blends

Reclamation of waste natural rubber gloves is carried out by mechano-chemical process using MBTS as reclaiming agent. The reclaim rubber is later blended with a virgin natural rubber at various blend ratios. The cure behavior and mechanical properties of the re-vulcanized blends are evaluated in comparison to the properties profile of the virgin materials. A significant increase in re-vulcanization rate is observed with increasing reclaim rubber contents. This property is most likely a consequence of the presence of active functional sites in the reclaim rubber. Additionally, the maximum torque as well as a torque difference increase with increasing reclaims rubber contents which are attributed to an increase in crosslink density of the blends. Moreover, the crosslink density also plays a major role in mechanical properties of the NR/reclaim rubber blends.

The influence of feed rate and shear forces on the devulcanization process of ground tire rubber (GTR) conducted in a co-rotating twin screw extruder

The search for new ways to recycling of rubber waste has been the aim of many studies conducted by research centers and companies worldwide. The results of our investigations on the process of continuous thermomechanical devulcanization of ground tire rubber using a twin screw extruder are presented. We used a co-rotating twin screw extruder with a special configuration of plasticizing unit, enabling generation of considerable shear forces. Various properties were characterized, such as the influence of the ground tire rubber feed rate and screw speed (shear forces) on the screw torque, acetone extract, sol fraction, and the degree of devulcanization in the resulting products. The effect of a secondary vulcanization on the vulcametric curves was determined, and the mechanical properties (tensile strength, elongation at break, hardness, resilience and abrasion resistance) of the revulcanized material were studied. It has been determined that the devulcanization process depends on the values of shear force and residence time acting on ground tire rubber. The devulcanization degree increases with increasing screw speed and feed rate. The results of repeatability of continuous devulcanization process of ground tire rubber were also determined. Obtained products possess the quality comparable to that of reclaim rubber available on the market.

Reinforcing effect of reclaim rubber on natural rubber/polybutadiene rubber blends

Mechanochemically devulcanized ground rubber tire (GRT) was revulcanized in a composition with natural rubber (NR) and polybutadiene rubber (PBR). Reclaiming of GRT was carried out by tetra methyl thiuram disulfide (TMTD) in the presence of spindle oil, a paraffin base rubber process oil. The cure characteristics and tensile properties of NR/PBR compounds were investigated. Results indicate that the minimum torque and Mooney viscosity of the NR/PBR compounds increase with increasing reclaim rubber (RR) loading whereas the scorch time remains unaltered but optimum cure time exhibits a decreasing trend due to the presence of active crosslinking sites in the reclaim rubber. The (re)vulcanization of different NR–PBR/RR blends was found to give a new low cost product with adequate properties. The mechanical properties before and after aging of NR–PBR/RR blend system and different proportions of carbon black loaded NR–PBR/RR blend system were studied. Tensile strength increases with increasing the proportion of reclaim rubber, but for all the vulcanizates the values are less than those of the control formulation. Thermogravimetric analysis of RR, NR–PBR and different NR–PBR/RR vulcanizates was carried out in order to get thermal stability of the vulcanizates. The effects of variations of RR loading on dynamic mechanical properties like loss tangent, storage and loss modulus were studied.

Reinforcing effect of nanosilica on the properties of natural rubber/reclaimed ground rubber tire vulcanizates

AbstractIn this investigation, incorporation of silica into natural rubber (NR)‐reclaim rubber (RR) blend system was carried out by sol‐gel technique at various sol‐gel reaction temperatures. The effect of RR on silica reinforcement, hitherto unexplored, was studied for different NR/RR blend systems. The degree of reinforcement of sol‐gel vulcanizates by equilibrium swelling method indicates that the reinforcing efficiency of the in situ generated silica by sol‐gel technique increases with increasing reclaim rubber content. The reinforcing efficiency, tensile properties and thermal stability of sol gel vulcanizates (SGV) prepared at 50°C become maxima as compared to SGV prepared at 30°C and 70°C. The amount of silica incorporated by sol‐gel technique was determined by thermogravimetry analysis. It indicates that the thermal stability increases with silica content. Attenuated total reflection study indicates that RR forms bond with silica particles due to the presence of active functional site on RR. Scanning electron microscopy studies further indicate the coherency and homogeneity in the silica filled NR/RR vulcanizates. The microwave diagnosis of different SGVs was also carried out and the frequency dependence of dielectric permittivity (E') and loss (E”) were measured. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

Processing and Material Characteristics of a reclaimed Ground Rubber Tire Reinforced Styrene Butadiene Rubber

Mechanochemically partially devulcanized ground rubber tire (GRT) was revulcanized in composition with virgin styrene butadiene rubber (SBR). Reclaiming of GRT was carried out by tetra methyl thiuram disulfide (TMTD) in presence of spindle oil. The cure characteristics and tensile properties of SBR compounds were investigated. Results indicate that the minimum torque and Mooney viscosity of the SBR compounds increase with increasing reclaim rubber (RR) loading whereas the scorch time remain unaltered but optimum cure time exhibit a decreasing trend. Increasing RR loading also gives SBR compounds better resistance towards swelling but the 100% modulus, 200% modulus tensile strength, and the elongation at break increases. Thermogravimetric analysis of SBR/RR vulcanizates was carried out in order to get thermal stability of the vulcanizates. Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the SBR/RR vulcanizates.

Thermoplastic elastomers from waste polyethylene and reclaim rubber blends and their composites with fly ash

Waste polyethylene (WPE) collected from the municipality solid waste (MSW) was melt blended with reclaim rubber (RR) in different proportions and composites with fly ash (FA) were prepared and characterized. Mechanical and dynamic mechanical properties of the blends and composites were studied in presence as well as in absence of a silane-coupling agent (Si-69). Tensile strength, flexural strength, flexural modulus, impact strength and hardness properties of the FA composites was found to improve in presence of Si-69. Phase morphology of the blends has been reported.

Reclaiming of ground rubber tire by a novel reclaiming agent. I. virgin natural rubber/reclaimed GRT vulcanizates

AbstractMechanochemically devulcanized ground rubber tire (GRT) was (re)vulcanized in compositions with virgin natural rubber (NR). The NR/GRT (re)vulcanizates with GRT content from 20 to 60 wt% have been prepared and studied. Reclaiming of GRT was successfully carried out by tetra methyl thiuram disulfide (TMTD) in presence of spindle oil at around ambient temperature. The cure characteristics and mechanical properties of the virgin NR/reclaim GRT blend were studied. The optimum cure time decreases but scorch time remain unaltered with increasing reclaim rubber content in the blend. Effect of carbon black was studied in NR/RR (80/20) blend. Ageing characteristics of different NR/RR blends were evaluated. Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the NR/RR vulcanizate. The dynamic mechanical properties and swelling behavior of NR/RR blend vulcanizates were examined. The elastic and storage modulus of the NR/RR vulcanizates become improve with increasing reclaim rubber content. Electrical properties of NR/RR vulcanizates were also studied. POLYM. ENG. SCI., 47:1091–1100, 2007. © 2007 Society of Plastics Engineers

Use of Recycled Tyre Material in Natural Rubber-Based Tyre Tread Cap Compound: Part I

For both environmental and economic reasons, there is a continuing broad-based interest in recycling of scrap rubber and in the development of recycling technologies. Among all the polymeric materials, the reuse of rubber vulcanisate is the most difficult, being thermosetting in nature the crosslinks formed are not easily broken down. In the present work, three different types of recycled materials (coarse reclaim, superfine reclaim and de-vulcanised rubber) were used in a natural rubber (NR) based bias tyre tread cap compound. Various quantities of the above ingredients were used as a replacement for virgin natural rubber. Chemical characterisation of the recycled material, the mixed rubber compound rheometric properties, unaged and air-aged stress strain properties, hardness, fatigue to failure, Demattia crack initiation, crack propagation, abrasion loss, volume fraction, rebound resilience, elastic modulus and dynamic mechanical properties were performed. In all levels of usage, the superfine reclaim rubber retained the properties to a greater extent when compared to the other recycled materials used in the study.

Reclaiming of ground rubber tire (GRT) by a novel reclaiming agent

The present paper describes the mechanical reclaiming of ground rubber tire (GRT) by tetra methyl thiuram disulfide (TMTD), a multi-functional reclaiming agent. The versatility of the proposed agent is that it acts as a reclaiming agent during reclaiming and as a curing agent during revulcanization of the reclaimed sample. Reclaiming of GRT was carried out on an open two roll mixing mill at various time intervals and different concentrations of the reclaiming agent (TMTD). The degree of reclaiming was evaluated by measurement of the gel content, inherent viscosity of sol rubber, Mooney viscosity of the reclaimed rubber, crosslink density, swelling ratio and molecular weight between two crosslink bonds as a function of milling time. Also, the influence of the gel content on crosslink density at various time intervals on the open two roll mixing mill was determined. A unique correlation between gel fraction and crosslink density obtained at various time intervals and concentrations of reclaiming agent indicated that an optimization of the concentration of TMTD and milling time has a positive influence on improving the efficiency of reclaiming. The reclaiming conditions have been optimized in view of the mechanical properties of the revulcanized GRT and the aging resistance properties of the revulcanized reclaim. The influence of the concentration of sulfur on the mechanical properties in the revulcanized reclaim was also studied. Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the revulcanized reclaim rubber when reclamation is carried out by optimum concentration of TMTD after maximum time of reclaiming.

Reinforcing effect of silica on the properties of styrene butadiene rubber–reclaim rubber blend system

AbstractIncorporation of silica into styrene butadiene rubber (SBR)–reclaim rubber (RR) blend system was carried out by sol–gel technique and conventional method. A well known silica coupling agent bis(3‐triethoxysilyl propyl) tetrasulfide was found to affect the curing characteristics and mechanical properties of SBR/RR vulcanizate. Here, the effect of RR on silica reinforcement was studied for different SBR/RR blend system. Silica incorporation by conventional mechanical mixing in absence of TESPT showed a much higher tensile properties than that of silica incorporated by the in situ sol–gel reaction of tetraethoxy silane both in presence and absence of TESPT. Studies of equilibrium swelling in a hydrocarbon solvent were also carried out. ATR study indicates that RR forms bond with silica particles due to the presence of active functional site on RR. The amount of silica incorporated by sol–gel reaction was determined through thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the silica filled SBR/RR vulcanizate. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 957–968, 2006

Reclaiming of rubber by a renewable resource material (RRM). III. evaluation of properties of NR reclaim

Sulfur-cured filled natural rubber (NR) is successfully reclaimed by using a renewable resource material (RRM) and diallyl disulfide (DADS), which is the major constituent of RRM. Reclaiming of NR vulcanizate was carried out at 60°C for 35 min in an open two-roll mixing mill. Evaluation of the properties of NR reclaim was carried out by mixing it with virgin rubber in various proportions. The cure characteristics and mechanical properties of the virgin NR/ reclaim NR blend were studied. With increase in the proportion of reclaim rubber (RR) in virgin NR/ reclaim NR blend scorch time and optimum cure time decrease. To increase scorch time N-cyclohexylthiophthalimide as prevulcanization inhibitor (PVI) was added in NR/RR (50/50) blend. It was found that use of 40% NR reclaim with virgin rubber resulted 83% retention of tensile strength of that of the virgin NR vulcanizate. Effect of carbon black loading was studied in NR/RR (50/50) blends. Tensile properties and swelling value of different NR/RR blends were evaluated before and after aging. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1493–1502, 2000

Reclaiming of rubber by a renewable resource material (RRM). II. Comparative evaluation of reclaiming process of NR vulcanizate by RRM and diallyl disulfide

Sulfur cured natural rubber vulcanizates were reclaimed by a vegetable product and diallyl disulfide under various reclaiming conditions. Progress of reclaiming was monitored by estimating the sol and gel portions, molecular weight determination of sol portions, and Mooney viscosity of reclaimed rubber. Tensile properties and swelling characteristics of revulcanized reclaim rubber were studied. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2951–2958, 1999

Penelitian pengaruh penambahan karet reclaim terhadap sifat- sifat kuat tarik, kemuluran dan volume terkikis kompon karet

Reprocessed of wastevulcanized rubber products, known as reclaim rubber, is used as a filler in rubber soles. Uncorrect usage of reclaim rubber in rubber sole manufacturing can decrease the product performance such as as tensile streangth, elongation break and abrasion resistance. In this experiment, by comparison of 30, 40, 50, 60 and 70 parts of reclaim rubber to the 100 part of natural rubber (RSS) sow that tensile strength decreased to 174.138, 160.118, 140.574, 134.092, and 449,60, 437.20, 426.00, 403.80 and 396.60% nrespectively, whereas abrasion resistance decreased to 0,2491, 0,4781, 0,5267, 0.7909, and mm 3 / kgm respectively.