Properties of oriented polymers

A simple but very useful principle is to consider that the elastic deformation of a single molecule occurs by three possible mechanisms (Fig. 9.20) bond stretching, bond-angle deformation and torsion about a a bond. The elastic constants for these three deformation mechanisms are very different. The following comparative values may be used 100 (bond stretching), 10 (bond angle deformation) and 1 (torsion about a a bond). 

The high axial elastic modulus of polyethylene and polyamide 6 is due to the fact that these polymers have a preferred conformation that is fully extended, i.e. all-trans. The elastic deformation is caused by the deformation of bond angles and by bond stretching, both showing high elastic constants. Isotactic polypropylene and polyoxymethylene crystallize in helical conformations and therefore exhibit a maximum stiffness which is only 20% of the maximum stiffness of the all-trans polymers. The elastic deformation of a helical chain involves, in addition to the deformation of bond angles and bond stretching, deformation by torsion about the G bonds. The latter 

The transverse modulus is determined by the weak secondary bonds and is for this reason only a small fraction of the axial (chain) elastic modulus. X-ray diffraction indicates the following values for linear polyethylene 300 GPa and E Ey 3 GPa. 

Uniaxial orientation simplified formula small/medium / values 

For ultra-oriented polymers good correlation only with draw ratio 

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D. 1. Bower, Structure and Properties of Oriented Polymers AppHed Sciences, London, U.K., 1975. 

Ward, I. M. Structure and properties of oriented polymers, Applied Science Publishers, London, (1975)... 

Ward, I. M., ed., Structure and Properties of Oriented Polymers, Ch. 13, 1973, London Applied Science. 

V.J. McBrierty and K.J. Packer, Nuclear Magnetic Resonance of Solid Polymers. Cambridge University Press, Cambridge, 1993 H.W. Spiess. In I.M. Ward (Ed.), Structure and Properties of Oriented Polymers, 2nd ed., Chapman Hall, London, 1997. 

Vaughan AS, Bassett DC (1989) Crystahizahon and morphology. In Allen G, Beving-ton JC (eds) Comprehensive polymer science, vol 1. Pergamon Press, London, chap 12 Peterlin A (1975) Molecular aspects of oriented polymers. In Ward JW (ed) Structure and properties of oriented polymers. Elsevier, London, p 46... 

Ward IM Ed, "Structure (aid Properties of Oriented Polymers" Applied Science Publishers, London, 1975. 

The existing subdivision of the book in seven Parts and 27 Chapters remained the same, with one exception chapter 14. This deals now with a new subject the Acoustic Properties its original subject, properties of oriented polymers, is now divided over the chapters 13 and 19. 

P.J. Mills, Chap. 9 in Structure and Properties of Oriented Polymers , Chapman Hall, London, 2nd. Edn., 1997. 

Phys. Conf. on Properties of Oriented Polymers, University of Leeds, April 1981. 

Bower, D. I. "Structure and Properties of Oriented Polymers" Applied Sciences London, 1975. 

However, the structure and properties of oriented polymers are characterised much more adequately by the molecular draw ratio mol [125]. The following expression relating and D to one another has been obtained [123] ... 

W. Hadley and I.M. Ward, iji "Structure and Properties of Oriented Polymers" ed. I.M. Ward, Appl.Sci. Publishers,... 

Adapted by permission of Kluwer Academic Publishers from L. Holliday and I. M. Ward A general introduction to the structure and properties of oriented polymers in Structure and Properties of Oriented Polymers, Ed. I. M. Ward, Applied Science Publishers, London, 1975, Chap. 1, pp. 1-35. 

Structure and Properties of Oriented Polymers, edited by I. M. Ward, 2nd Edn, Chapman and Hall, London, 1997. This is in general an advanced monograph, but some sections are less diflacult than others. The book concentrates on methods of studying oriented polymers and the results obtained, but also includes some material on the production of orientation. 

I. M. Ward (ed.), Structure and Properties of Oriented Polymers, Halsted Press, New York, 1975. B. Jasse and J. L. Koenig, Orientational measurements in polymers using vibrational spectroscopy, 7. Macromol. Sci. Revs. Macromol. Chem.) C17, 61 (1979). 

A GENERAL INTRODUCTION TO THE STRUCTURE AND PROPERTIES OF ORIENTED POLYMERS... 

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