Polymer Matrix Composites and Technology

Ru-Min Wang, Shui-Rong Zheng, Yujun George Zheng

• Publisher: Woodhead Publishing
• Year: 2011
• eBook ISBN: 9780857092229
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Given such properties as low density and high strength, polymer matrix composites have become a widely used material in the aerospace and other industries. Polymer matrix composites and technology provides a helpful overview of these materials, their processing and performance.After an introductory chapter, part one reviews the main reinforcement and matrix materials used as well as the nature of the interface between them. Part two discusses forming and molding technologies for polymer matrix composites. The final part of the book covers key aspects of performance, including tensile, compression, shear and bending properties as well as impact, fatigue and creep behaviour.Polymer matrix composites and technology provides both students and those in industry with a valuable introduction to and overview of this important class of materials.- Provides a helpful overview of these materials, their processing and performance incorporating naming and classification of composite materials- Reviews the main reinforcement and matrix materials used as well as the nature of the interface between them including damage mechanisms- Discusses forming and molding technologies for polymer matrix composites outlining various techniques and technologies

1

Introduction to polymer matrix composites

1.1 Introduction

Materials are the basis for improving human production and living standards. They provide milestones in human progress. Humans have been accessing and using materials for several thousand years. Looking over the history of human civilization, we will find that its development is about human access and use of materials using social productive forces, science and technology. It reflects human ability to understand and transform nature. Whenever there is a new epoch-making material, productivity will also receive a huge development and human society will leap forward. Therefore, materials have become a symbol of the progress of human civilization, and have become milestones for dividing eras of human history. From the material point of view, human society has experienced the Stone Age, Bronze Age, and Iron Age. High-performance plastics and composites, which appeared in the 20th century, have infiltrated to the national economy and people’s lives in various fields with a rare rate of development in the history. They have become the substitutes for traditional materials, showing improved performance. Now, with the rapid development of science and technology, materials play an important role in the national economy and defense. New materials are the basis of new technologies, and materials science, energy technology and information science have become the three pillars of modern science and technology.

Materials science is the integrated discipline. It is closely related to a wide range of other disciplines. It explains the laws of materials’ macroscopic properties from the chemical composition and the principle of internal structure, and then develops a set of principles in designing, manufacturing and using new materials with specific properties. It mainly includes three parts contents:

from the chemical point of view, the relationship of the chemical composition of materials and each component is researched, and the relationship between the composition and performance is researched, and the preparation methods of materials are researched;

from the physical point of view, the performance of material is studied, and the relationship between the internal structure of materials (the combination of atoms and molecules, the arrangement distribution in space and the state of aggregation) and performance is studied;

under the guidance of chemical and physical theory, the technical problems which related to the preparation and application of materials are researched.

There are many different types of materials. Basically, they can be divided into three types of materials with vastly different performance by the way the atoms or molecules are bonded together (the main combination bonds):

metallic materials, metal elements are combined by metal bonds;

organic polymer materials, non-metallic elements are bonded covalently to macromolecular compounds;

ceramic materials, non-metallic elements and metal elements are combined by covalent bonds, ionic bonds, or a mixture of the two bonds. From the service performance point, there are two main types of materials:

structural materials;

functional materials. For structural material, its mechanical properties, such as strength, stiffness, deformation and so on, are majorly considerd, while for functional material, its sound, light, electricity, heat and magnetic properties are mainly used. In this case, we should know the behavior of materials in sound, light, electricity, heat and magnetic field.

As the rapid development of modern science and technology, there are more harsh special requirements for materials. The research of material is gradually breaking away from the track of researching by experiences and fumbling methods. It develops in the direction of material designing according to the designed properties. The composite material which is made of metallic, non-metallic and polymeric material by certain processes, can retain the advantages of the original components, overcomes some shortcomings and show some new properties. The emergence and development of such composite materials is a classic example of material designing.

Composite material is a multi-phase system consisted of matrix material and reinforcing material. Matrix material is a continuous phase, and it includes metal matrix composite materials, inorganic non-metallic matrix composite materials and polymer matrix composites by the different matrix materials. Reinforcing material is a dispersed phase, usually fibrous materials such as glass fiber, organic fiber and so on. We only discuss polymer matrix composites in this book.

Polymer matrix composite material is the one that uses organic polymer as matrix and fiber as reinforcement. Strength and modulus of fiber are much higher than the matrix material normally. This makes fibers the main load-bearing component. However, there must be a matrix material with good adhesion properties to firmly bond fibers together. At the same time, the matrix material can serve to uniformly distribute the applied load, and transfer the loads to fiber. In addition, some properties of composite materials mainly depend on the characteristics of the matrix material. As a result, in composite materials, the performance of fiber, matrix and the interface between them directly impact on the performance of composite materials.

1.2 The definition of composite materials

The term of composite materials was firstly used in abroad in the 1950s, and it has been used domestically from about the 1960s. Composite material is a kind of complex multi-component multi-phase system, and it is difficult to be defined accurately. A concise definition is shown: composite material is a multi-phase combination material of two or more component materials with different properties and different forms through compounding processes, it not only maintains the main characteristics of the original component, but also shows new character which are not possessed by any of the original components. Composite materials should have the following characteristics:

microscopically it is non-homogeneous material and has a distinct interface;

there are big differences in the performance of component materials;

the formed composite materials should have a great improvement in performance;

the volume fraction of component materials are larger than 10%. According to this definition, composite materials in a wide range of areas, straw mud wall, steel bar reinforced concrete, and tire cord, etc. all belong to the scope of composite materials.

From analysis of the composition and the internal structure of composite materials we found that it includes three basic physical phases. One is called matrix phase which is continuous, another is called reinforcement which is scattered and surrounded by the matrix. The other is called composites’ interface which is an interface between reinforcement phase and matrix phase. For further study on micro-structure level, we found that, owing to the complex physical and chemical reasons in compounding process, the reinforcement phase and the matrix phase near the interface become a complex structure which is different from both of the matrix phase and the reinforcement phase of their own. And at the same time, we found that the structure and morphology have an impact on macroscopic performance of composites, so the microscopic area near the interface changes in structure and properties. Thus it becomes the third phase of composites, which is called interphase. Therefore, composite material is composed of matrix phase, reinforcement phase and interphase. The structure and the nature of these three phases, their configuration and interaction, as well as the relative content determine the performance of composite materials.

“Material Dictionary” edited by Changxu Shi gave a more comprehensive and integrity definition on composite material: “Composite materials are new materials that are combinations of different types of materials, such as organic polymers, inorganic non-metal or metal and so on, through compound technology. It not only retains the key feature of the original component materials, but also gets the performances that are not depicted by the original components through the combined effects. Materials designing can make the performance of each component to mutual supplement and interrelate to each other, thus produce a new superiority of performance, which has essential differences from general materials mixed simply.” The definition stresses the important feature of composite materials that they are designable. In industry, composite materials are usually referred to the materials with excellent integrated performance which is made of reinforcement with high-strength, high modulus and brittleness, and matrix material with low modulus and toughness by a certain processing process. Composite materials discussed in modern materials science are generally referred to as fiber, sheet, and particle reinforced, or self-reinforced polymer matrix, ceramic matrix or metal matrix composites. This definition grasps the essence of the composite materials, namely the enhancing concept by enhancer. The fiber is the most widely used and the most effective reinforcement, so the composite material that people often talk about is a narrow meaning of composite materials, i.e. fiber-reinforced composite materials, which are discussed in this book.

1.3 Naming and classification of composite materials

1.3.1 Naming of composite materials

The development of many new materials is before their scientific name, so traditionally we often firstly use a number of popular names. For example, domestic compos...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Author contact details
• Preface
• Chapter 1: Introduction to polymer matrix composites
• Part I: Component materials
• Part II: Processing of composite materials
• Part III: Performance of composite materials
• Index