Page 719 - Carrahers_Polymer_Chemistry,_Eighth_Edition

682 Carraher’s Polymer Chemistry

11. (a).
12. Preferably X-ray diffraction; NMR may also be used, and so on.
13. DSC, DTA, TML, TBA, and so on.
14. Structural characterization focuses on determining the structure, generally repeat unit or second-
ary structure, of a material. Such techniques may also give information on the physical proper-
ties of a material. In fact, physical properties are directly related to overall polymer structure.
15. Standard tests allow tests to be carried out in laboratories over the world and results to be com-
pared in some reliable fashion. They also assist the researcher in carrying out the tests since
such ASTM tests are described in great detail.
16. The answer depends on what “better” means. Because of modern instrumentation, we have both
“better” instruments capable of obtaining useful information not available to scientists 30 years
ago. Further, many modern instruments are set up to take duplicate measurements quickly and
perform statistical treatments of the data, allowing a greater confidence in results.

17. Vinyl polymers have carbon–carbon backbones that have very similar thermal stabilities so that
when one degrades, releasing a fragment resulting in weight loss, other carbon–carbon bond
scissions occur that results in the production of some statistical average of fragmentation occur-
ing dependent on a number of factors, including heating rate and polymer structure.
18. Most tests that determine the amount of crystallinity and amorphous character a sample has,
give results dependent on the particular test. Since the polymer has a variety of molecular-level
structures that can be classified as either depending on the particular test, it is not surprising

that the end result does not add up to 100%.

19. Few materials are truly flame proof but only resist burning to some extent. Thus, even the suits

used by firemen will burn under the right set of conditions. Further, these terms help guard the

manufacturer against law suites when their material catches fire under extreme conditions and
are intended to discourage people to assuming they will not be hurt if they are in a fi re because
of the presence of the particular fl ame-resistant material.
20. The hurdles vary but include increased cost and the need to train people to carry out such safety
applications/practices. In the automotive industry, added weight may also be a hurdle. Overall,
change typically must overcome hurdles to occur. Even so, industry is sensitive to issues of
safety issues.

CHAPTER 14

1. Morphology is the study of shape, while rheology is the study of flow and deformation.

2. (b) and (d).
3. G is the shear modulus.
4. (c).
5. Compressive, pulling, and shear.
6. Movement of part or all of the chain.
7. (a) has a low modulus and high viscosity, therefore the viscosity/G will be large.
8. Bond fl exing.
9. Compliance is a ratio of strain divided by stress.

10. Having both flow and glassy or solid behavior.
11. As a solid or a glassy material.
12. At a temperature of 35ºC above the T of the polystyrene, that is about 140ºC.
g
13. Young’s modulus is a ratio of stress to strain. High.

14. The coefficient of viscosity is equal to the ratio of the applied stress to the applied velocity
gradient.
15. Stress relaxation.
16. (b).
17. ASTM.

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