PLASTICS. Characterization and Failure Analysis of.

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1 Characterization and Failure Analysis of PLASTICS

2 Copyright 2003 by ASM International All rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the written permission of the copyright owner. First printing, December 2003 Great care is taken in the compilation and production of this book, but it should be made clear that NO WAR- RANTIES, EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES OF MER- CHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE GIVEN IN CONNECTION WITH THIS PUBLICATION. Although this information is believed to be accurate by ASM, ASM cannot guarantee that favorable results will be obtained from the use of this publication alone. This publication is intended for use by persons having technical skill, at their sole discretion and risk. Since the conditions of product or material use are outside of ASM s control, ASM assumes no liability or obligation in connection with any use of this information. No claim of any kind, whether as to products or information in this publication, and whether or not based on negligence, shall be greater in amount than the purchase price of this product or publication in respect of which damages are claimed. THE REMEDY HEREBY PROVIDED SHALL BE THE EXCLUSIVE AND SOLE REMEDY OF BUYER, AND IN NO EVENT SHALL EITHER PARTY BE LIABLE FOR SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES WHETHER OR NOT CAUSED BY OR RESULTING FROM THE NEGLI- GENCE OF SUCH PARTY. As with any material, evaluation of the material under end-use conditions prior to specification is essential. Therefore, specific testing under actual conditions is recommended. Nothing contained in this book shall be construed as a grant of any right of manufacture, sale, use, or reproduction, in connection with any method, process, apparatus, product, composition, or system, whether or not covered by letters patent, copyright, or trademark, and nothing contained in this book shall be construed as a defense against any alleged infringement of letters patent, copyright, or trademark, or as a defense against liability for such infringement. Comments, criticisms, and suggestions are invited and should be forwarded to ASM International. ASM International staff who worked on this project include Steve Lampman, Editor; Bonnie Sanders, Manager of Production; Nancy Hrivnak, Jill Kinson, and Carol Polakowski, Production Editors; and Scott Henry, Assistant Director of Reference Publications. Library of Congress Cataloging-in-Publication Data Characterization and failure analysis of plastics. p. cm. Collection of articles from ASM International handbooks. Includes bibliographical references and index. 1. Plastics Fracture. I. ASM International. TA455.P5C dc ISBN: SAN: ASM International Materials Park, OH Printed in the United States of America

3 Preface This book is collection of ASM Handbook articles on how engineering plastics are characterized and understood in terms of properties and performance. It approaches the subject of characterization from a general standpoint of engineering design, materials selection, and failure analysis. These basic activities of the engineering process all require clear understanding of plastics performance and properties by various methods of physical, chemical, and mechanical characterization. The first section introduces the fundamental elements of engineering plastics and how composition, processing, and structure influence their properties and performance. The second section contains articles on material selection and design, where the requirements of a plastic part are synthesized and analyzed in terms of function, shape, process, and materials. The next sections then cover the important physical, chemical, and mechanical properties of plastics. The last section covers failure analysis, which is the ultimate stage of characterization in the life of a part, but really only the penultimate stage in the overall engineering process. Failure analysis, in a broad sense, is another iteration of the design process, as it can provide important information on product and process improvements. Thus, it closely ties together with the characterization of properties and performance plastics during design and materials selection. This book would not have been possible without the original contributions from the authors of the Handbook articles. Thanks are extended to them. Steve Lampman May 2003 iii

4 Contents Introduction Engineering Plastics: An Introduction Polymer Structure Chemical Composition and Structure Polymer Names Properties of Polymers Engineering Thermoplastics Engineering Thermosets Effects of Composition, Processing, and Structure on Properties of Engineering Plastics Composition Thermal and Mechanical Properties Viscoelasticity Properties of Engineering Plastics and Commodity Plastics Electrical Properties Optical Properties Chemical Properties Processing Materials Selection and Design of Engineering Plastics General Design Guidelines Defining End-Use Requirements Part Geometry Strength of Plastics Cost Estimating Plastics Parts Stucture, Properties, Processing, and Applications Design with Plastics Mechanical Part Performance Manufacturing Considerations Design-Based Material Selection Conclusions Design and Selection of Plastics Processing Methods Plastics Processing Methods Injection Molding Extrusion Thermoforming Blow Molding Rotational Molding Compression Molding and Transfer Molding Composites Processing Casting Design Features and Process Considerations Other Plastics Design and Processing Considerations Materials-Selection Methodology Function and Properties Factors in Process Selection Establishing Functional Requirements Properties Considerations and Processing Process Effects on Molecular Orientation Thermoplastic Process Effects on Properties Thermosetting Process Effects on Properties Size, Shape, and Design Detail Factors in Process Selection Part Size Factors in Process Selection Shape and Design Detail Factors in Process Selection Physical, Chemical, and Thermal Analysis of Plastics Physical, Chemical, and Thermal Analysis of Thermoset Resins Chemical Composition Characterization Processing Characterization Physical, Chemical, and Thermal Analysis of Thermoplastic Resins 105 Molecular Weight Determination from Viscosity The Use of Cone and Plate and Parallel Plate Geometries in Melt Rheology Chromatography Thermoanalysis Thermal Analysis and Thermal Properties Glass Transition Temperature Semicrystalline Polymers Structural and Test Effects Moisture Effect on Tg Thermal Analysis Differential Scanning Calorimetry Thermogravimetric Analysis Thermomechanical Analysis Thermal Properties Determination of Service Temperature Service Temperature Thermal Properties of Thermoplastics Thermal Properties of Thermosets Low-Temperature Resin Systems Medium-Temperature Resin Systems High-Temperature Resin Systems Environmental and Chemical Effects Chemical Susceptibility Absorption and Transport Additive Effects Thermal Degradation Thermal Oxidative Degradation Photo-oxidative Degradation Environmental Corrosion Chemical Corrosion Degradation Detection Effect of Environment on Performance Plasticization, Solvation and Swelling iv

5 Environmental Stress Cracking Polymer Degradation by Chemical Reaction Surface Embrittlement Temperature Effects Characterization of Weather Aging and Radiation Susceptibility Degradation Factors Test Methods Flammability Testing Fire Resistance of Polymeric Materials Overview of the Burning Process Flammability Test Methods Electrical Testing and Characterization Electrical Tests Electrical Properties of Plastics and Their Characterizations Terminology Optical Testing and Characterization Transmission and Haze Yellowness Refractive Index Birefringence Surface Irregularity and Contamination Surface Gloss and Color Ad Hoc Testing Mechanical Behavior and Wear Mechanical Testing and Properties of Plastics: An Introduction Tensile Properties Other Strength/Modulus Tests Creep Data Analysis Dynamic Mechanical Properties Impact Toughness Hardness Tests Fatigue Testing Elastomers and Fibers Creep, Stress Relaxation, and Yielding Creep Failure Stress Relaxation Failure Yield Failure Effect of Crystallinity The Aging of Polymers Crazing and Fracture General Polymeric Behavior Ductile-Brittle Transitions Crazing Fracture Environmental Effects Initiation Criteria Craze Growth Effect of Crazing on Toughness Testing for Brittle Behavior Fracture Toughness Testing Fracture Resistance Testing Historical Development Fracture Test Methods for Polymers Impact Loading and Testing Material Considerations in Impact Response Design and Analysis Techniques for Thin Plastic Components Summary Fatigue Testing and Behavior Fatigue Crack Initiation Fatigue Crack Propagation Factors Affecting Fatigue Performance of Polymers Factography Fatigue Failure Mechanisms Mechanisms of Fatigue Failure Thermal Fatigue Failure Mechanical Fatigue Failure Friction and Wear Testing Friction, Wear, and Lubrication Friction and Wear Test Methods Friction and Wear Test Data for Polymeric Materials Wear Failures of Plastics Interfacial Wear Cohesive Wear Elastomers Thermosets Glassy Thermoplastics Semicrystalline Thermoplastics Environmental and Lubricant Effects on the Wear Failures of Polymers Summary and Case Study Failure Examples Wear Failures of Reinforced Polymers Abrasive Wear Failure of Reinforced Polymers Sliding (Adhesive) Wear Failure of Polymer Composites Environmental Effects Thermal Stresses and Physical Aging Classification of Stress Thermal Stresses Orientation Effects Physical Aging Use of High-Modulus Graphite Fibers in Amorphous Polymers Environmental Stress Crazing Molecular Mechanism Environmental Criteria Material Optimization Testing Moisture-Related Failure Mechanisms of Moisture-Induced Damage Effect of Moisture on Mechanical Properties Organic Chemical Related Failure Chemical Interactions Physical Interactions Photolytic Degradation Sunlight Polymer Photochemistry Protection of Plastics from Sunlight v

6 Microbial Degradation Biodegradation Mechanisms Biodeterioration and Biodegradation Definitions Biodeterioration and Biodegradation Measurements Experimental Example Failure Analysis of Plastics Analysis of Structure Problem Solving Molecular Spectroscopy Molecular Weight Methods of Thermal Analysis X-Ray Diffraction (XRD) Analysis Scheme for Polymer Analysis Procedure for Analyzing Milligram Quantities of Polymer Sample Characterization of Plastics in Failure Analysis Fourier Transform Infrared Spectroscopy Differential Scanning Calorimetry Thermogravimetric Analysis Thermomechanical Analysis Dynamic Mechanical Analysis Methods for Molecular Weight Assessment Mechanical Testing Considerations in the Selection and Use of Test Methods Case Studies Surface Analysis Scanning Electron Microscopy Chemical Characterization of Surfaces Auger Electron Spectroscopy X-Ray Photoelectron Spectroscopy Time-of-Flight Secondary Ion Mass Spectrometry Application Examples Example 1: Delamination of Polyester Insulation from Brass Cable Connectors Example 2: Printed Circuit Boards Example 3: Paint Delamination from a Molded Cabinet Example 4: Delamination of a Surface-Mounted Integrated Circuit (IC) from a Solder Pad Fracture and Fractography Structure and Behavior Crack Propagation Fractography Case Studies Fractography of Composites Interlaminar Fracture Features Translaminar Fracture Features Conclusion Reference Information Abbreviations and Symbols Index vi

7 ASM International is the society for materials engineers and scientists, a worldwide network dedicated to advancing industry, technology, and applications of metals and materials. ASM International, Materials Park, Ohio, USA This publication is copyright ASM International. All rights reserved. Publication title Product code Characterization and Failure Analysis of Plastics #06978G To order products from ASM International: Online Visit /bookstore Telephone (US) or (Outside US) Fax Mail Customer Service, ASM International 9639 Kinsman Rd, Materials Park, Ohio , USA CustomerService@asminternational.org In Europe In Japan American Technical Publishers Ltd Knowl Piece, Wilbury Way, Hitchin Hertfordshire SG4 0SX, United Kingdom Telephone: (account holders), (credit card) Neutrino Inc. Takahashi Bldg., 44-3 Fuda 1-chome, Chofu-Shi, Tokyo 182 Japan Telephone: 81 (0) Terms of Use. This publication is being made available in PDF format as a benefit to members and customers of ASM International. You may download and print a copy of this publication for your personal use only. Other use and distribution is prohibited without the express written permission of ASM International. No warranties, express or implied, including, without limitation, warranties of merchantability or fitness for a particular purpose, are given in connection with this publication. Although this information is believed to be accurate by ASM, ASM cannot guarantee that favorable results will be obtained from the use of this publication alone. This publication is intended for use by persons having technical skill, at their sole discretion and risk. Since the conditions of product or material use are outside of ASM's control, ASM assumes no liability or obligation in connection with any use of this information. As with any material, evaluation of the material under end-use conditions prior to specification is essential. Therefore, specific testing under actual conditions is recommended. Nothing contained in this publication shall be construed as a grant of any right of manufacture, sale, use, or reproduction, in connection with any method, process, apparatus, product, composition, or system, whether or not covered by letters patent, copyright, or trademark, and nothing contained in this publication shall be construed as a defense against any alleged infringement of letters patent, copyright, or trademark, or as a defense against liability for such infringement.

Surface Hardening of Steels Understanding the Basics

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