Understanding the Differences Between PAN-Based and Pitch-Based Carbon Fiber

Fiber and fiber may differ in spelling but the material and pronunciation remain the same, despite their variations in regional preferences. Carbon fiber, a lightweight yet strong material, has been widely used in various industries due to its unique properties. Specifically, carbon fiber can be broadly categorized into two main types: PAN-based carbon fiber and pitch-based carbon fiber. This article delves into the differences and applications of these two types to provide a comprehensive understanding of their characteristics.

Introduction to Carbon Fiber Types

Carbon fiber is a versatile material known for its superior mechanical properties. It is primarily classified into two categories based on its structure and production process: PAN-based carbon fiber and pitch-based carbon fiber. This article aims to highlight the distinct differences between these two types to help you choose the right one for your specific needs.

PAN-Based Carbon Fiber

Source Material

PAN-based carbon fiber is derived from polyacrylonitrile, a synthetic polymer. The choice of this source material plays a crucial role in determining the properties and performance of the eventual carbon fiber.

Production Process

The production process for PAN-based carbon fiber involves several stages. Initially, polyacrylonitrile is spun into fibers, followed by stabilization, carbonization, and surface treatment. This rigorous process ensures the fibers have high strength and durability.

Properties

Tensile Strength

PAN-based carbon fiber typically exhibits higher tensile strength and stiffness compared to pitch-based carbon fiber. This makes it ideal for applications where structural integrity is paramount.

Strength-to-Weight Ratio

Due to its lightweight characteristics and high strength, PAN-based carbon fiber offers an excellent strength-to-weight ratio. This property is highly prized in sectors such as aerospace, automotive, and sporting goods.

Applications

PAN-based carbon fiber is commonly employed in:

Aerospace: Passenger and commercial aircraft, spacecraft components, and structural components. Automotive: Lightweight body parts, structural components, and performance enhancements. Sporting Goods: Bicycles, tennis rackets, golf clubs, and other sports equipment. High-Performance Applications: Military vehicles, high-strength industrial machinery, and specialized manufacturing.

Pitch-Based Carbon Fiber

Source Material

pitch-based carbon fiber is derived from petroleum pitch or coal tar pitch, making it a different source material from PAN-based carbon fiber. This difference in origin directly influences the properties of the resulting fiber.

Production Process

The production process for pitch-based carbon fiber is somewhat simpler as it involves spinning pitch into fibers and then directly proceeding to carbonization without a stabilization step. This direct process imparts superior thermal properties to pitch-based carbon fiber.

Properties

Elastic Modulus

Pitch-based carbon fiber tends to have a higher modulus of elasticity, meaning it is stiffer but less strong than PAN-based carbon fiber. This unique characteristic makes it suitable for applications that require high thermal resistance.

Thermal and Electrical Conductivity

Compared to PAN-based carbon fiber, pitch-based carbon fiber boasts better thermal and electrical conductivity. This property makes it valuable in fields such as battery electrodes and industrial applications requiring heat management.

Applications

Pitch-based carbon fiber is often used in:

High-Temperature Applications: Motor engines, brake systems, and baking equipment. Electronics: Battery electrodes, conductive materials, and high-temperature electronics. Industrial Applications: Heat-resistant films, aerospace components, and structural elements.

Summary

In summary, PAN-based carbon fiber is characterized by its higher tensile strength and stiffness, making it more suitable for structural applications. On the other hand, pitch-based carbon fiber is known for its higher modulus, thermal conductivity, and better thermal management capabilities. The choice between the two ultimately depends on the specific requirements of the application at hand.

Tailoring Carbon Fiber to Specific Applications

Within the category of carbon fiber, there are different types differentiated by their moduli, each serving unique functions:

Standard Modulus Carbon Fiber

Standard modulus carbon fiber, with a modulus of around 33 million psi, is a general-purpose material commonly used in sporting goods and industrial applications. This type offers a balance of strength and stiffness, making it versatile and widely applicable.

Intermediate Modulus Carbon Fiber

With a modulus of around 42 million psi, intermediate modulus carbon fiber is stiffer than standard modulus fiber, making it ideal for high-performance sporting goods and aerospace applications. This level of stiffness and strength strikes a balance that meets the demands of many advanced applications.

High Modulus Carbon Fiber

High modulus carbon fiber, with a modulus of around 57 million psi, is the stiffest and strongest carbon fiber. It is widely used in aerospace and defense applications, where extraordinary strength and durability are essential.

Ultra-High Modulus Carbon Fiber

Ultra-high modulus carbon fiber, with a modulus of around 85 million psi, is the strongest carbon fiber available. This type is used in specialized aerospace and defense applications, where the highest levels of performance are required.

The choice of carbon fiber ultimately depends on the specific application and requirements such as strength, stiffness, and weight. For example, standard modulus carbon fiber may be suitable for applications requiring moderate strength and stiffness, while high modulus carbon fiber is required for applications demanding higher strength and stiffness. Cost and availability are also important factors to consider. A qualified materials engineer can provide guidance on selecting the appropriate carbon fiber for a particular application.