Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Chapter 7Polymers: Structure, GeneralProperties and Applications

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Mechanical Properties of Engineering Plastics

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Chapter 7 Topics

Figure 7.1 Outline of the topics described in Chapter 7.

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Structure of Polymer Molecules

Figure 7.2 Basic structure of polymermolecules: (a) ethylene molecule; (b)polyethylene, a linear chain of manyethylene molecule; and (c) molecularstructure of various polymers. Theseare examples of the basic buildingblocks for plastics.

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Polymerization

Figure 7.3 Examples of polymerization. (a) Condensation polymerization of nylon 6,6and (b) addition polymerization of polyethylene molecules from ethylene mers.

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

The Effect of Molecular Weight and Degree ofPolymerization on Polymers

Figure 7.4 Effect of molecularweight and degree ofpolymerization on the strength andviscosity of polymers.

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Polymer Chains

Figure 7.5 Schematic illustration of polymer chains. (a) Linear structure – thermoplasticssuch as acrylics, nylons, polyethylene, and polyvinyl chloride have linear structures. (b)Branched structure, such as in polyethylene. (c) Cross-linked structure – many rubbers orelastomers have this structure, and the vulcanization of rubber produces this structure. (d)Network structure, which is basically highly cross-linked – examples are thermosettingplastics, such as expoxies and phenolics.

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Behavior of Polymers

Figure 7.6 Behavior of polymers as a function of temperature and (a) degree ofcrystallinity and (b) cross-linking. The combined elastic and viscous behavior ofpolymers is known as viscoelasticity.

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Microstructure of Polymethylmethacrylate Cement

Figure 7.7 Schematic illustration of the microstructure ofpolymethylmethacrylate cement used in dental and mental applications.

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Amorphous and Crystalline Regions in a Polymer

Figure 7.8 Amorphous and crystalline regions in a polymer. The crystallineregion (crystallite) has an orderly arrangement of molecules. The higherthe crystallinity, the harder, stiffer, and less ductile the polymer.

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Volume of Polymers as a Function of Temperature

Figure 7.9 Specific volume ofpolymers as a function oftemperature. Amorphous polymers,such as acrylic and polycarbonate,have a glass-transition temperature,Tg, but do not have a specificmelting point, Tm. Partly crystallinepolymers, such as polyethylene andnylons, contract sharply whilepassing through their meltingtemperatures during cooling.

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Glass-Transition and Melting Temperatures of Polymers

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Types of Plastics

Figure 7.10 General terminology describing the behavior of three types of plastics. PTFE(polytetrafluoroethylene) has Teflon as its trade name. Source: After R.L.E. Brown

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Effect of Temperature on the Stress-strain Curvefor Cellulose Acetate

Figure 7.11 Effect of temperature on the stress-strain curve for cellulose acetate, athermoplastic. Note the large drop in strength and the large increase in ductility with arelatively small increase in temperature. Source: After T.S. Carswell and H.K. Nason.

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Effect of Temperature on Plastic Impact Strength

Figure 7.12 Effect oftemperature on the impactstrength of various plastics.Small changes in temperaturecan have a significant effecton impact strength. Source:After P.C. Powell

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Load-Elongation Curve and Tensile-Test Specimen

Figure 7.13 (a) Load-elongation curve for polycarbonate, a thermoplastic. Source:Courtesy of R. P. Kambour and R. E. Robertson. (b) High-density polyethylene tensile-testspecimen, showing uniform elongation (the long, narrow region in the specimen).

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Plastic Product Recommendations

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Thermoplastic Polymer Trade Names

Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Load-Elongation Curve for Rubbers

Figure 7.14 Typical load-elongationcurve for rubbers. The clockwiseloop, indicating the loading and theunloading paths, displays thehysteresis loss. Hysteresis givesrubbers the capacity to dissipateenergy, damp vibration, and absorbshock loading, as is necessary inautomobile ties and in vibrationdampers placed under machinery.