PI Plastic Materials | Polyimide Sheet, Rod, Tube & Custom Parts
High-Performance Polyimide Materials and Precision Machined Components for High-Temperature, Wear, Electrical Insulation and Vacuum Applications
PI (polyimide) is an advanced high-performance engineering plastic for environments where conventional polymers fail. Great Plastics supplies polyimide sheet, rod and tube stock plus precision custom CNC machined parts for high-temperature wear, electrical insulation, vacuum and precision applications.
MOQ (Min. Order)
From 1 piece for prototypes and drawing-based parts; production MOQ confirmed per grade and drawing.
FOB Port
FOB Shenzhen / Shanghai / Ningbo available; exact port, Incoterms and freight confirmed at quote.
Lead Time
Stock shapes ~5–7 working days; custom CNC parts 7–15 working days depending on grade, quantity and machining.
Samples
Samples available on request; sample cost, quantity and lead time confirmed quotation stage
QC & Inspection
In-process inspection, dimensional reports and third-party inspection supported; quality plan agreed from the drawing.
Payment & Support
T/T and other terms discussed per order; engineering support included with every inquiry.
Available Forms
PI Plastic Forms & Custom Parts
Start from standard stock shapes or go straight to a machined component. All forms are available in virgin and filled polyimide grades.
Performance Data
Polyimide Plastic Material Properties
Typical data for an unfilled (virgin) thermoset polyimide grade, presented in the standard format used for engineering material data sheets.
| PROPERTY | TEST METHOD | TYPICAL VALUE | UNIT |
|---|---|---|---|
| Physical Properties | |||
| Density | ISO 1183 | ~1.43 | g/cm³ |
| Water absorption (24 h) | ASTM D570 | ~0.24 | % |
| Mechanical Properties | |||
| Tensile strength (23 °C) | ASTM D638 | ~87 | MPa |
| Tensile modulus | ASTM D638 | ~2.5 | GPa |
| Flexural strength | ASTM D790 | ~110 | MPa |
| Compressive strength | ASTM D695 | ~117 | MPa |
| Elongation at break | ASTM D638 | ~7.5 | % |
| Hardness | Shore D | ~92 | Shore D |
| Thermal Properties | |||
| Glass transition temperature | DSC | ~360 | °C |
| Continuous service temperature | — | ~260 | °C |
| Short-term peak temperature | — | ~400 | °C |
| Coefficient of thermal expansion | ASTM E831 | ~54 | ppm/K |
| Electrical Properties | |||
| Dielectric strength | ASTM D149 | ~22 | kV/mm |
| Volume resistivity | ASTM D257 | >1014 | Ω·cm |
Overview
Why Engineers Specify PI Plastic Materials
PI stands for polyimide, a family of aromatic high-performance polymers whose molecular backbone contains repeating imide groups. This rigid, aromatic structure gives polyimide outstanding thermal and mechanical stability. In engineering terms, PI belongs to the class of ultra-high-temperature plastics, alongside materials such as PAI and PBI, and it is available in both thermosetting and thermoplastic forms.
Engineers choose polyimide plastic when component temperature, friction, vacuum cleanliness or precision requirements exceed the practical limits of other engineering thermoplastics. Because polyimide retains strength and electrical insulation where ordinary plastics soften or degrade, it is specified in semiconductor manufacturing, aerospace, vacuum systems and precision industrial machinery — often outlasting cheaper alternatives and reducing downtime.
Material Selection
PI Material Grades & Filler Selection
Polyimide is compounded with different fillers to tune friction, wear, stiffness and load capability. Select by your dominant operating requirement.
| GRADE / FILLER | BEST FOR | AVOID WHEN | RFQ INPUTS |
|---|---|---|---|
| Virgin (unfilled) PI | Maximum temperature, best electrical insulation and dimensional stability | Lowest cost or impact toughness is the priority | Service temperature, electrical & vacuum requirements |
| Graphite-filled PI | Dry-running wear: bearings, bushings, seal rings | Lowest friction coefficient matters more than wear life | Sliding speed, PV factor, counterface material |
| PTFE-filled PI | Lowest-friction sliding and sealing: wear rings, seals | High-load structural duty | Friction requirement, media, temperature |
| Carbon fiber reinforced PI | High-load, high-stiffness aerospace and mechanical parts | Where electrical insulation is required (carbon fiber conducts) | Load, stiffness, environment |
| Glass-filled / MoS2-filled PI | Tailored stiffness or friction (available on request) | — | Application detail for compound selection |
Industry Use Cases
Applications of PI Plastic Materials
For each industry below we list typical PI components, why polyimide is used, and the key inputs we need to quote your part.
Manufacturing Capability
PI Machining and Custom PI Parts
Reliable polyimide components depend on machining discipline as much as material quality. Great Plastics combines both in-house.
Polyimide can be machined into complex, close-tolerance components, but it is not like machining ordinary plastics. Its hardness and very low thermal conductivity concentrate heat at the cutting edge, so controlled feeds, speeds and tooling are essential:
Typical PI parts we machine include bushings, bearings, seals, wear rings, insulators, sleeves and wafer-handling components — from single prototypes to OEM production runs.
Material Comparison
PI vs Other Engineering Plastics
One decision table for the materials most often compared with PI. Choose by temperature, strength, chemical, machinability and cost.
| FACTOR | PI | PEEK | PPS | PTFE | PAI |
|---|---|---|---|---|---|
| Typical continuous temperature | ~260 °C | ~250 °C | ~220–240 °C | ~260 °C | ~250 °C |
| Mechanical strength | High | High | Moderate | Low | Highest |
| Wear / friction tuning | Excellent with fillers | Excellent | Good | Lowest friction | Excellent |
| Chemical resistance | Good | Outstanding | Outstanding | Outstanding | Good |
| Electrical insulation | Excellent | Excellent | Good | Excellent | Good |
| Machinability | Demanding | Easier | Easier | Easy | Demanding |
| Relative cost | High | Medium | Lower | Medium | Highest |
| Best when | Highest temp, wear, insulation | Tough, broad chemical, economy | Cost + solvent resistance | Lowest friction, inert | Highest strength / temp duty |
PI provides a higher temperature ceiling and better long-term thermal stability than PEEK, while PEEK is generally easier to machine and more affordable. PPS and PTFE serve cost- and friction-driven duties respectively, and PAI competes at the very top of the temperature-strength range. The final choice should be confirmed against the grade datasheet and your load, media and budget.
Common Questions
Frequently Asked Questions
Quick answers to the questions engineers and procurement teams ask most about PI materials.