Recycled butyl rubber

Chandra and Pillai [28] used a low-molecular-weight recycled rubber as a processing aid in a number of tyre tread formulations and compared its performance with other commercial process aids. This process aid (Ecoreen T) is shown to function as well as or even better than depolymerised NR or similar process aids. The same workers also reported on the use of new products with low viscosity that are produced by blending low-molecular-weight virgin polymers with recycled butyl rubber [29]. When these products... 

BR, butyl rubber CB, carbon black CBS, cyclohexyl-2-benzothiazolefulfenamide CNT, carbon nanotube CSPE, chlorosulfonate polyethylene CIP, carbonyl-iron powder EPM, ethylene propylene monomer EPDM, ethylene propylene diene monomer EVA, ethylene-vinyl acetate FSR, fluorosilane rubber GRP, graphite powder HGM, hollow glass microsphere lONP, iron oxide nanoparticle LDH, layered double hydroxide MBT, 2-mercaptobenzothiazol MMT, modified montmorillonite NR, natural rubber PAMAM, polyamidoamine R-EPDM, recycled ethylene propylene diene monomer SR, silicon rubber SBR, styrene-butadiene rubber TBBS, iV-tert-butyl-2-benzothiazolesulfenamide. 

The purified isobutylene is then blended with a recycled methyl chloride stream containing a low level of isobutylene ( 5%). Finally, the comonomer, iso-prene or p-methylstyrene, is added. In this blending process, control of the ratio of comonomer to isobutylene is very important. This is because it has a significant impact on the composition of the polymer produced, the conversion of monomer, and the stability of reactor operation. For these reasons, a combination of both an analyzer and a mass balance control can be used to maintain the composition of the feed blend. The feed blend contains 20-40 wt% of isobutylene and 0.4-1.4 wt% of isoprene or 1-2 wt% of p-methylst5Tene, depending on the grade of butyl rubber to be produced the remainder is methyl chloride. 

A new class of solvents called ionic liquids has been developed to meet this need. A typical ionic liquid has a relatively small anion, such as BF4, and a relatively large, organic cation, such as l-butyl-3-methylimidazolium (16). Because the cation has a large nonpolar region and is often asymmetrical, the compound does not crystallize easily and so is liquid at room temperature. However, the attractions between the ions reduces the vapor pressure to about the same as that of an ionic solid, thereby reducing air pollution. Because different cations and anions can be used, solvents can be designed for specific uses. For example, one formulation can dissolve the rubber in old tires so that it can be recycled. Other solvents can be used to extract radioactive waste from groundwater. 

Figure 14.9 Effect of various impact modifiers (25wt%) on the notched Izod impact strength of recycled PET (as moulded and annealed at 150°C for 16 h) E-GMA, glycidyl-methacrylate-functionalized ethylene copolymer E-EA-GMA, ethylene-ethyl acrylate-glycidyl methacrylate (72/20/8) terpolymer E-EA, ethylene-ethyl acrylate EPR, ethylene propylene rubber MA-GPR, maleic anhydride grafted ethylene propylene rubber MBS, poly(methyl methacrylate)-g-poly(butadiene/styrene) BuA-C/S, poly(butyl acrylate-g-poly(methyl methacrylate) core/shell rubber. Data taken from Akkapeddi etal. [26]...

Karaaga, B., en, M., Deniz, V., Giiven, O. Recycling of gamma irradiated inner tubes in butyl based rubber. Nucl. Instmm. Meth. Phys. Res. B 265, 290-293 (2005)... 

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