CB6956 Polybenzimidazole Powder (PBI Powder)

Polybenzimidazole Powder (PBI Powder) Description

PBI powder provides high-temperature polymer properties. It has a glass transition temperature (Tg) of 435°C, which is among the highest measured for commercial polymers. There is no observable melting point, thereby permitting continuous use in air at 400°C and short‐term exposure up to 500°C. The oxygen index is 58%, which exceeds that of many engineering plastics (e.g., PEEK: 35%), indicating that the material is non‐flammable and self‐extinguishing.

Mechanically, the powder exhibits a tensile strength of 130 MPa, an elastic modulus of 5.5 GPa and a Shore D hardness of 97. It maintains 20% elongation at break. These values persist at elevated temperatures.

Electrochemically, the powder acts as an insulator with a volume resistivity of 2×10¹⁵ Ω·cm and a dielectric strength of 23 kV/mm. The dielectric constant remains within 3.3–3.4 across frequencies from 1 kHz to 0.1 MHz. The dissipation factor is less than 0.003, which is appropriate for aerospace and energy applications.

Chemically, the material is resistant to aggressive media. It remains stable in strong acids (concentrated H2SO4, HNO3), bases (50% NaOH), and organic solvents (ketones, alcohols, fuels), as well as in steam. Its performance in alkaline environments exceeds that of PTFE. The material also tolerates high-energy radiation (gamma/X‐rays) and exhibits minimal outgassing in vacuums.

The powder is processed by compression moulding (powder → billets) or solution casting (for films/fibres). It is used to form components for rocket nozzles, semiconductor fixtures, firefighting equipment and fuel cell membranes. The main limitations are its high cost and dark amber colour.

Polybenzimidazole Powder (PBI Powder) Applications

PBI powder is used in aerospace and defence. It is applied in the manufacture of rocket engine seals, thermal protection systems and re‐entry vehicle components that operate above 400°C. It is also utilised in high‐temperature industrial equipment such as chemical valve seals, bearing cages and non‐lubricated bushings in refineries, where it resists corrosive media (acids, bases, steam) and abrasive wear. In energy technology, PBI‐based membranes are employed in fuel cells (PEM electrolyzers), utilising proton conductivity under low humidity and thermal conditions. The powder is compression moulded into firefighting equipment (hoods, gloves) and aviation fire barriers, based on an oxygen index of 58% and the absence of toxic fume emission.

In semiconductor manufacturing, PBI is used for wafer handling fixtures, plasma etch components and vacuum chamber insulators. This application is due to its low outgassing, radiation stability and consistent dielectric properties. Emerging uses include deep‐well drilling tools for geothermal and oil extraction, and solution‐cast films (e.g. VR05 grade) for lightweight thermal shields in electric vehicles. Its durability in thermal and chemical environments compensates for the higher cost.

Polybenzimidazole Powder (PBI Powder) Packaging

The products are packaged in customised cartons of various sizes according to the material dimensions. Small items are placed in PP boxes, while larger items are packed in custom wooden crates. Appropriate cushioning materials are used to protect the products during transport.

Packaging: Carton, Wooden Box, or Customised.

Please review the packaging details provided for your reference.

Manufacturing Process

1.      Testing Method

(1)    Chemical Composition Analysis – Samples are analysed using techniques such as GDMS or XRF to confirm compliance with purity requirements.

(2)    Mechanical Properties Testing – Tensile strength, yield strength and elongation are measured to assess material performance.

(3)    Dimensional Inspection – Thickness, width and length are measured to verify adherence to specified tolerances.

(4)    Surface Quality Inspection – Visual and ultrasonic examinations are conducted to detect defects such as scratches, cracks or inclusions.

(5)    Hardness Testing – Material hardness is measured to confirm uniformity and mechanical reliability.

Please refer to the testing procedures provided by SAM for further details.

Polybenzimidazole Powder (PBI Powder) FAQs

Q1. What defines PBI powder's core capability?

The powder has a glass transition temperature of 435°C and supports continuous use at 400°C. It has an oxygen index of 58% and demonstrates resistance to acids, bases, solvents and steam. These measured values exceed those of PEEK, PTFE and metals under high-stress conditions.

Q2. Top industrial applications?

PBI powder finds use in aerospace thermal shields (rocket nozzles, re‐entry vehicles), chemical industry seals and valves (resistant to 98% H2SO4), fuel cell proton‐exchange membranes (maintaining proton conductivity at high temperatures) and semiconductor fixtures (exhibiting low outgassing under vacuum and plasma conditions).

Q3. How does it process into components?

The powder is processed by compression moulding at 400–450°C to form billets, or by solution casting after dissolution in DMAc/LiCl for films and fibres. For instance, VR05 (film grade) permits the production of coatings below 50 μm for thermal barriers.

Related Information

1.      Common Preparation Methods

PBI powder is synthesised by a high-temperature solution polycondensation reaction between 3,3',4,4'-tetraaminobiphenyl (TAB) and diphenyl isophthalate (DPIP) in a suitable solvent system. The process begins with the rigorous drying of monomers under vacuum to eliminate moisture and oxygen. Polymerisation occurs in polyphosphoric acid (PPA) or N-methyl-2-pyrrolidone (NMP) at 200–250°C under an inert atmosphere (nitrogen/argon), with PPA acting as both a solvent and dehydrating agent to facilitate imidazole ring formation. The reaction proceeds in two stages. Initially, at temperatures up to 150°C, an ester–amine interchange produces soluble prepolymers. Subsequently, thermal cyclisation at temperatures not less than 200°C forms benzimidazole rings. After 4–12 hours, the viscous solution is quenched in water or alkaline baths, and the polymer precipitates as a fibrous solid. The crude PBI is purified by reflux washing (methanol/KOH) to remove catalysts and oligomers, then mechanically milled into a fine powder. Final steps include vacuum drying at 150–200°C to achieve a moisture content below 0.1% and sieving to control the particle size distribution (typically 10–200 μm) for moulding, film casting (e.g. VR05 grade) or fibre extrusion. Alternative routes, such as melt-solid polymerisation for higher molecular weights, require temperatures above 400°C and specialised reactors.