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Polyimide Granules

Updated: 2026-08-26

Overview

Polyimide granules are a class of high-performance polymers synthesized from aromatic dianhydrides and diamines. They are renowned for their ability to retain mechanical and electrical properties at temperatures exceeding 250°C, making them indispensable in extreme environments. First developed in the 1960s, polyimides fill a critical gap between conventional plastics and ceramics. Their molecular structure features rigid aromatic rings and imide linkages, contributing to exceptional thermal oxidative stability and radiation resistance.

Physical and Chemical Properties

Polyimide granules exhibit a unique combination of properties unmatched by most polymers. Their glass transition temperatures typically range from 250°C to 400°C, with continuous use temperatures up to 300°C. The tensile strength can reach 100-200 MPa, comparable to some metals. Chemically, they resist hydrolysis, organic solvents, and weak acids/bases. However, prolonged exposure to strong alkalis or concentrated sulfuric acid may cause degradation. The dielectric constant remains stable (2.5-3.5) across a wide frequency range, ideal for electronic applications.

Main Applications

In aerospace, polyimide granules are processed into bushings, bearings, and insulation for spacecraft due to their outgassing resistance in vacuum conditions. The electronics industry uses them for flexible printed circuit boards, chip carriers, and LED substrates. Automotive applications include under-hood components and electric vehicle battery insulation. Emerging uses encompass medical implants (for biocompatible grades) and filtration membranes for aggressive chemical environments.

Safety and Storage

While polyimide itself is non-toxic, processing at high temperatures may release trace amounts of volatile compounds. Adequate ventilation and NIOSH-approved particulate respirators are recommended during machining or grinding operations. Granules should be stored in sealed containers with desiccants to prevent moisture absorption, which can affect processing. Shelf life typically exceeds 2 years when stored below 30°C and 50% relative humidity.

B2B Procurement Guide

Industrial buyers should prioritize suppliers with ISO 9001 certification and material traceability. Key specifications to confirm include: thermal index (UL rating), coefficient of thermal expansion, and flame retardancy (UL94 V-0 is common). For custom formulations, discuss fillers (e.g., graphite for lubricity, glass fibers for stiffness) and color requirements. Minimum order quantities often start at 25kg, with lead times of 4-8 weeks for specialty grades. Consider regional suppliers to reduce logistics costs for bulk orders.

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