Polybutadiene rubber compounding

This lower has a number of ramifications on the properties of polybutadiene. For example, at room temperature polybutadiene compounds generally have a higher resilience than similar natural rubber compounds. In turn this means that the polybutadiene rubbers have a lower heat build-up and this is important in tyre applications. On the other hand, these rubbers have poor tear resistance, poor tack and poor tensile strength. For this reason, the polybutadiene rubbers are seldom used on their own but more commonly in conjunction with other materials. For example, they are blended with natural rubber in the manufacture of truck tyres and, widely, with SBR in the manufacture of passenger car tyres. The rubbers are also widely used in the manufacture of high-impact polystyrene. 

Polybutadiene based compounds can be cured by sulphur, sulphur donor systems and peroxides. Less sulphur and a higher level of accelerators are required when compared to NR. The cure of polybutadiene by peroxides is highly efficient in that a large number of crosslinks are produced per free radical, the resultant highly crosslinked rubber exhibiting high resilience this factor is utilised in the manufacture of superballs . 

Polybutadiene (PB), 9 558 14 246 24 703 commercial block copolymers, 7 648t oxygen permeability at 25°C, 3 400 physical properties of, 4 376t in rubber compounding, 21 764-765 synthesis, 4 375-377 in tire compounding, 21 807 nel-Polybutadiene, 7 610t Polybutadiene-based urethane sealants, 22 36... 

The information on physical properties of radiation cross-linking of polybutadiene rubber and butadiene copolymers was obtained in a fashion similar to that for NR, namely, by stress-strain measurements. From Table 5.6, it is evident that the dose required for a full cure of these elastomers is lower than that for natural rubber. The addition of prorads allows further reduction of the cure dose with the actual value depending on the microstructure and macrostructure of the polymer and also on the type and concentration of the compounding ingredients, such as oils, processing aids, and antioxidants in the compound. For example, solution-polymerized polybutadiene rubber usually requires lower doses than emulsion-polymerized rubber because it contains smaller amount of impurities than the latter. Since the yield of scission G(S) is relatively small, particularly when oxygen is excluded, tensile... 

Catalysts. Iodine and its compounds are very active catalysts for many reactions (133). The principal use is in the production of synthetic rubber via Ziegler-Natta catalysts systems. Also, iodine and certain iodides, eg, titanium tetraiodide [7720-834], are employed for producing stereospecific polymers, such as polybutadiene rubber (134) about 75% of the iodine consumed in catalysts is assumed to be used for polybutadiene and polyisoprene polymerization (66) (see Rubber CHEMICALS). Hydrogen iodide is used as a catalyst in the manufacture of acetic acid from methanol (66). A 99% yield as acetic acid has been reported. In the heat stabilization of nylon suitable for tire cordage, iodine is used in a system involving copper acetate or borate, and potassium iodide (66) (see Tire cords). 

As a means to improve the rubber utilization, a bulk/suspension process evolved, whereby polybutadiene rubber was dissolved in styrene monomer and polymerized in bulk beyond phase inversion before being dropped into suspension. The HIPS produced this way had two distinct advantages over the compounded version styrene to rubber grafting and discrete rubber spheres or particles uniformly dispersed in a polystyrene matrix. This improved the impact strength dramatically per unit of rubber and gave better processing stability, because the rubber phase was dispersed instead of being co-continuous with the polystyrene. 

Non-discoloring, sulfur containing phenolic antioxidant and stabilizer that provides long-term heat stability by preventing thermo-oxidative degradation. Used for the process stabilization of polyethylene wire and cable resins for polyethylene during extruder compounding. Can also be applied in styrenic polymers, polypropylene, elastomers such as EPDM and SBR and for carboxylated SBR latex, polybutadiene rubber and polyisopropene rubber. 

Chapman, A.V. Tinker, A.J. The effect of low molecular weight polybutadiene as processing aid on properties of silica-filled rubber compounds. Kautschuk Gummi K 2003, 56, 533. 

The samples of surface devulcanized reclaimed rubber made in this series of experiments were then compounded with a blend of virgin rubbers and cured. The blends were made by mixing 20 parts per 100 parts of rubber (phr) of the surface devulcanized reclaimed rubber samples with 70phr of Plioflex 1712 SBR, 30 phr of Budene 1254 polybutadiene rubber, about 9 phr of aromatic oil, about 70 phr of carbon black, about 2 phr of stearic acid, about 4 phr of wax, about 1 phr of accelerator, about 2 phr of zinc oxide, about 1.5 phr of sulfur, and about Iphr of antioxidant. The Plioflex 1712 has a bound styrene content of about 28.5% and was oil extended with about 37.5% of an... 

Acrylic acid, zinc salt Ageflex ZDA EINECS 238-692-3 2-Propenoic acid, zinc salt Zinc acrylate Zinc dlacrylate. Crosslinker for molded polybutadiene compounds, conductive and protective coatings, coagent for SBR compounds and reactive pigments activator for rubber compounding scorch retarder. Rit-Chem. 

Polybutadiene Higher resilience than similar natural rubber compounds, good low-temperature behavior and adhesion to metals, but poor tear resistance, poor tack, and poor tensile strength Blends with natural rubber and SBR manufacture of high-impact polystyrene... 

The chemical resistance of polybutadiene is similar to that of natural rubber. It shows poor resistance to aliphatic and aromatic hydrocarbons, oil, and gasoline, but it displays fair to good resistance in the presence of mineral acids and oxygenated compounds. Refer to Table 5.13 for the compatibility of polybutadiene rubber with selected corrodents. 

Though the preparation of blends can enhance material performance properties, there are losses in other characteristics. Addition of polybutadiene to natural rubber compounds results in a drop in tensile strength, ultimate elongation, and tear strength. For example, on addition of 50 phr of polybutadiene to an all natural rubber compound, and having all of the carbon black in the polybutadiene phase, the tensile strength drops from 24.5 to 17.5 MPa. With all the carbon black in the natural rubber phase only, the tensile strength drops further to 15.8 MPa (Table 4.12) [1, 2]. 

Similar trends are observed in compounds with only 25 phr of polybutadiene added to the natural rubber compound (Table 4.13). The tensile strength drops from 23.1 to 17.4 MPa, with the location of the carbon black playing a critical role in generation of the compound mechanical properties. Several observations can be noted ... 

In view of the long history of research efforts on filled rubbers, it is not surprising that the initial works on filled polymer blends appeared in publications authored by rubber compounders and carbon black vendors [17, 18]. For instance, Walters and Keyte [17] observed that the compound ingredients, such as CB and zinc oxide, were not homogenously dispersed in rubber blends. Hess et al. [18] also reported a series of fundamental observations. First, they observed that filler particles tend to remain in the lower viscosity phase, in the absence of significant filler-matrix interactions. However, in the presence of strong polar-polar interactions between the filler particles and one of the phases, the particles were found to be selectively dispersed in the more polar phase and the viscosity became less important. More recently. Portal et al. [19] also presented similar observations about selective localization of CB particles in the natural rubber (NR) phase in NR/ polybutadiene blends. 

Acrylate styrene acrylonitrile Acrylate modified styrene acrylonitrile Acrylic acid ester rubber Acrylonitrile butadiene rubber or nitrile butadiene rubber Acrylonitrile butadiene styrene Acrylonitrile styrene/chlorinated polyethylene Acrylonitrile methyl methacrylate Acrylonitrile styrene/EPR rubber or, acrylonitrile ethylene propylene styrene Alpha methyl styrene Atactic polypropylene Butadiene rubber or, cis-1,4-polybutadiene rubber or, polybutadiene rubber Butadiene styrene block copolymer Butyl rubber Bulk molding compound Casein formaldehyde Cellulose acetate Cellulose acetate butyrate Cellulose acetate propionate Cellulose nitrate Chlorinated polyethylene Chlorinated polyvinyl chloride Chloro-polyethylene or, chlorinated polyethylene. 

Modern composite propellants are heterogeneous powders (mixtures) which use a crystallized or finely ground mineral salt as an oxidizer, often ammonium perchlorate, which constitutes between 60 and 90% of the mass of the propellant. The fuel itself is highly pyrophoric aluminum metal powder. The propellant is held together by a polymeric binder, usually polyurethane or polybutadienes. Additional compounds are sometimes included, such as a catalyst to help increase the burning rate, or other agents to make the powder easier to manufacture. The final product is a rubber-like substance with the consistency of a hard rubber eraser. 

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