10.23 - E45 Lecture Chapter 4 CHAPTER 4 POLYMER STRUCTURES ISSUES TO ADDRESS What are the general structural and chemical characteristics of

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 4 - E45 Lecture 10/23/09
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chapter 4 - 2 ISSUES TO ADDRESS. .. What are the general structural and chemical characteristics of polymer molecules? What are some of the common polymeric materials , and how do they differ chemically? How is the crystalline state in polymers different from that in metals and ceramics ? Mechanical and electrical properties of polymers CHAPTER 4: POLYMER STRUCTURES
Background image of page 2
Chapter 4 - 3 What is a Polymer? Poly mer many repeat unit Adapted from Fig. 4.2, C C C C C C H H H H H H H H H H H H Polyethylene (PE) Cl Cl Cl C C C C C C H H H H H H H H H Poly(vinyl chloride) (PVC) H H H H H H Polypropylene (PP) C C C C C C CH 3 H H CH 3 CH 3 H repeat unit repeat unit repeat unit
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chapter 4 - 4 Applications of Polymers UHMWPE for surgical implants LDPE for sandwich bags XLPE for electrical insulation of underground high voltage power lines
Background image of page 4
Chapter 4 - 5 Advanced Polymers Molecular weight ca. 4 x 10 6 g/mol Outstanding properties high impact strength resistance to wear/abrasion – low coefficient of friction – self-lubricating surface Important applications – bullet-proof vests golf ball covers hip implants (acetabular cup) UHMWPE Adapted from chapter- opening photograph, Chapter 22, Callister 7e. Ultrahigh Molecular Weight Polyethylene (UHMWPE)
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chapter 4 - 6 Applications of Polymers UHMWPE for surgical implants LDPE for sandwich bags XLPE for electrical insulation of underground high voltage power lines UHMWPE, LDPE, XLPE are all PE but with different microstructures
Background image of page 6
Chapter 4 - Polyethylene for high voltage insulation What makes PE an electrical insulator? Why do PE insulators of high voltage lines “age” and fail?
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chapter 4 - 8 Polymer Composition Most polymers are hydrocarbons – i.e., made up of H and C Saturated hydrocarbons Each carbon singly bonded to four other atoms Example: • Ethane, C 2 H 6 C C H H H H H H
Background image of page 8
Chapter 4 - 9
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chapter 4 - 10 Unsaturated Hydrocarbons Double & triple bonds somewhat unstable – can form new bonds – Double bond found in ethylene or ethene - C 2 H 4 – Triple bond found in acetylene or ethyne - C 2 H 2 C C H H H H C C H H
Background image of page 10
Chapter 4 - 11 Isomerism Isomerism two compounds with same chemical formula can have quite different structures for example: C 8 H 18 normal-octane 2,4-dimethylhexane C C C C C C C C H H H H H H H H H H H H H H H H H H H 3 C CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 = H 3 C CH CH 3 CH 2 CH CH 2 CH 3 CH 3 H 3 C CH 2 CH 3 ( ) 6
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chapter 4 - 12 Polymerization and Polymer Chemistry Free radical polymerization Initiator : example - benzoyl peroxide C H H O O C H H C H H O 2 C C H H H H monomer (ethylene) R + free radical R C C H H H H initiation R C C H H H H C C H H H H + R C C H H H H C C H H H H propagation dimer R = 2
Background image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/16/2009 for the course ENGIN 45 taught by Professor Devine during the Fall '07 term at University of California, Berkeley.

Page1 / 45

10.23 - E45 Lecture Chapter 4 CHAPTER 4 POLYMER STRUCTURES ISSUES TO ADDRESS What are the general structural and chemical characteristics of

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online