Permeability Properties of Plastics and Elastomers

Laurence W. McKeen

• Publisher: William Andrew
• Year: 2011
• ISBN:
  9781437734706
• Edition: 3
• Topic: Technology & Engineering
• Subtopic: Chemical & Biochemical Engineering
• Index: Technology & Engineering

Permeability properties are essential data for the selection of materials and design of products across a broad range of market sectors from food packaging to Automotive applications to Medical Devices. This unique handbook brings together a wealth of permeability data in a form that enables quick like-for-like comparisons between materials.

The data is supported by a full explanation of its interpretation, and an introduction to the engineering aspects of permeability in polymers.

The third edition includes expanded explanatory text which makes the book accessible to novices as well as experienced engineers, written by industry insider and author Larry McKeen (DuPont), and 20% new data and major new explanatory text sections to aid in the interpretation and application of the data.

• A unique collection of permeability data designed to enable quick like-for-like comparisons between different materials
• Third edition includes 20% new data and expanded explanatory text, which makes the book accessible to novices as well as experienced engineers
• Essential reference for materials engineers, design engineers and applications engineers across sectors including packaging, automotive and medical devices

1. Introduction to Permeation of Plastics and Elastomers

This chapter focuses on the basics of permeation, what it is, how it occurs, how it is measured, and how its data are presented. A brief history is covered. Effusion, solution-diffusion, and pore-flow models are explained and contrasted. The basis for most permeation measurements, time-lag plots, is analyzed in detail. Sample calculations based on the time-lag experiment make it easier to understand. The dependence of permeation on temperature and pressure is discussed. The section on standard testing includes a listing of all common standards of gas permeation and vapor transmission. The special tests and analysis for coating/paint permeation are also covered in detail.

This book is about the passage of liquids, vapors, or gases through plastic or polymeric materials, such as films, membranes, and containers. The passage of small molecules through solid materials is called permeation. Permeability properties are important in many applications and are important in everyday life. The small molecule that passes through the solid is called the permeant. The permeability of the packaging materials (wrapping films, containers seals, closures, etc.) needs to be matched with the sensitivity of the packaged contents to that permeant and the specified shelf life. Some packages must have nearly hermetic seals, while others can (and sometimes must) be selectively permeable. Knowledge about the exact permeation rates is therefore essential. There are many examples for the importance of permeation properties, some are as follows:

• The air pressure in tires should decrease as slowly as possible, so it is good to know which gas permeates slowest through the rubber wall and at what rate.

• Packaged meat needs to retain its moisture within the package to prevent it from drying out, but it needs to keep oxygen out too, which slows down spoilage.

• The water vapor permeation of insulating material is important to protect underlying from corrosion.

• To meet legal regulations, e.g., California Air Resource Board (CARB) for low-emission vehicles, it is essential to use barrier materials for fuel hoses and tanks.

This first chapter focuses on permeation, what it is, how it occurs, how it is measured, and how its data are presented. The second chapter covers polymer chemistry and plastics composition and how composition affects permeation. The third chapter concentrates on production of films, containers, and membranes. The fourth chapter focuses on the uses of barrier films, containers, and membranes.

Chapter 5, Chapter 6, Chapter 7, Chapter 8, Chapter 9, Chapter 10, Chapter 11, Chapter 12, Chapter 13 and Chapter 14 are a databank that serves as an evaluation of permeation performance of plastics. Each of these chapters starts with a brief outline of the chemistry of the polymer in that section. There are hundreds of uniform graphs and tables for more than 60 generic families of plastics that are contained in these chapters. The data in each chapter are generally organized with chemistry, a manufacturer and trade name list, and an applications and uses list followed by the data.

1.1. History

It appears that the first scientific mention of water permeation was made by a physicist, Abbé Jean-Antoine Nollet (1700–1770). ¹ Nollet sealed wine containers with a pig's bladder and stored them under water. After a while, he noticed that the bladder bulged outward. Because of his scientific curiosity, he did the experiment the other way round: he filled the container with water and stored it in wine. The result was a shrinking inward of the bladder. This was an evidence of water permeation through the pig's bladder from an area of high concentration to an area of lower concentration.

The first study of gas permeation through a polymer was conducted by Thomas Graham in 1826. ² Graham observed a loss in volume of a wet pig bladder inflated with carbon dioxide. In 1831, John Kearsley Mitchell, p...

Table of contents

• Cover image
• Table of Contents
• Dedication
• Series Page
• Front Matter
• Copyright
• Preface
• 1. Introduction to Permeation of Plastics and Elastomers
• 2. Introduction to Plastics and Polymers
• 3. Production of Films, Containers, and Membranes
• 4. Markets and Applications for Films, Containers, and Membranes
• 5. Styrenic Plastics
• 6. Polyesters
• 7. Polyimides
• 8. Polyamides (Nylons)
• 9. Polyolefins, Polyvinyls, and Acrylics
• Chapter 10. Fluoropolymers
• 11. High-Temperature and High-Performance Polymers
• 12. Elastomers and Rubbers
• 13. Environmentally Friendly Polymers
• 14. Multilayered Films
• Appendix A. Conversion Factors
• Appendix B. Reference Fuel Compositions
• Appendix C
• Index