| High-Cis Polybutadiene Rubber | Approximately 90–98% | Approximately 0.5–3% | Approximately −105 to −108°C | Typically 40–65 ML(1+4) at 100°C | Very high resilience, low heat build-up, excellent abrasion resistance, and good low-temperature flexibility. | Tire tread compounds, tire sidewalls, conveyor belts, impact modification, golf-ball cores, and dynamic rubber products. | Request cis/vinyl microstructure, Mooney viscosity, Tg, ash, volatile matter, gel content, antioxidant type, and batch-to-batch consistency data. |
| Medium-Cis Polybutadiene Rubber | Approximately 70–85% | Approximately 5–15% | Approximately −95 to −103°C | Typically 35–60 ML(1+4) at 100°C | Balanced resilience, processability, abrasion resistance, and blending flexibility. | General-purpose tire compounds, molded parts, footwear, hoses, belts, and rubber blends. | Compare cure behavior, molecular-weight distribution, branching, mixing performance, and compatibility with natural rubber or styrene-butadiene rubber. |
| Low-Cis Polybutadiene Rubber | Approximately 30–50% | Approximately 8–20% | Approximately −75 to −90°C | Typically 35–70 ML(1+4) at 100°C | Good flow and processability, useful impact modification, and a potentially lower material cost than specialty high-cis grades. | Polystyrene and engineering-plastic impact modification, adhesives, general rubber compounds, and selected molded products. | Check residual solvent, gel level, color, odor, stabilizer package, impact-modifier efficiency, and suitability for the target polymer matrix. |
| High-Vinyl Polybutadiene Rubber | Usually below 40%, depending on grade | Approximately 35–90% | Approximately −20 to −75°C, depending strongly on vinyl level | Typically 30–70 ML(1+4) at 100°C | Higher polarity and increased glass-transition temperature compared with high-cis grades; can improve wet grip, stiffness, or compatibility in selected blends. | Specialty tire compounds, polymer modification, adhesives, sealants, and formulated elastomer systems. | Verify vinyl distribution, Tg, cure compatibility, plasticizer response, dynamic-mechanical properties, and temperature resistance. |
| Solution-Polymerized BR Grade | Grade-dependent; commonly 35–98% | Grade-dependent; commonly 1–60% | Approximately −110 to −20°C | Typically 35–75 ML(1+4) at 100°C | Broad design flexibility in microstructure, molecular weight, branching, and functionalization; performance can be tailored to specific formulations. | Advanced tire compounds, high-performance rubber blends, adhesives, sealants, and specialty elastomer products. | Ask for polymerization method, molecular-weight distribution, functional end groups, catalyst residues, trace metals, and processing recommendations. |
| Emulsion-Polymerized BR or BR-Containing Blend | Variable; confirm exact composition | Variable; confirm exact composition | Usually higher than high-cis solution grades; grade-specific | Grade-specific; commonly 30–80 ML(1+4) at 100°C | May provide convenient processing and blend economics, but microstructure and purity can differ significantly from solution grades. | General rubber goods, modified plastics, adhesives, and cost-sensitive formulations where the required performance is moderate. | Confirm whether the product is pure BR or a blend; request surfactant, soap, residual electrolyte, moisture, and ash information. |
| Key Supplier-Selection Specifications to Compare |
| Microstructure | 1,4-cis, 1,4-trans, and 1,2-vinyl percentages | Use the same analytical method when comparing suppliers | Microstructure strongly affects Tg, resilience, heat build-up, abrasion, and cure response. | Select according to the required balance of rolling resistance, wet grip, impact resistance, and processability. | Request infrared, NMR, or equivalent test data and the stated test method. |
| Mooney Viscosity and Processability | Commonly reported as ML(1+4) at 100°C | Target range depends on mixing equipment and compound design | Higher viscosity can support green strength but may require greater mixing energy. | Confirm laboratory value, production variation, and recommended mastication or blending procedure. | Use ASTM D1646 or an equivalent declared standard. |
| Purity and Residuals | Ash, volatile matter, moisture, gel, residual monomer, and catalyst-related metals | Limits must match the application and regulatory requirements | Impurities can affect odor, color, curing, electrical properties, aging, and surface quality. | Especially important for automotive interiors, electrical parts, light-colored goods, and sensitive adhesives. | Request a recent certificate of analysis and an impurity-control statement. |
| Quality Consistency and Supply Capability | Lot-to-lot variation in viscosity, microstructure, Tg, and stabilizer content | Evaluate at least three production lots when possible | Consistent properties reduce formulation adjustments, scrap, and production interruptions. | Review lead time, minimum order quantity, packaging, storage life, and emergency supply options. | Request quality certificates, change-notification procedures, production capacity information, and sample approval records. |
| Compliance, Safety, and Sustainability | Safety Data Sheet, technical data sheet, regulatory status, and restricted-substance information | Requirements depend on destination market and end use | Documentation supports safe handling, import compliance, customer audits, and product qualification. | Check applicable chemical-registration, transport, packaging, and restricted-substance requirements. | Request current SDS, regulatory declarations, recycled-content or carbon information when relevant, and written change-control commitments. |
