Chain contour length between entanglements

The first molecular variable to be considered is chain entanglement density. It is known that this factor, as well as a related parameter, viz. the average chain contour length between entanglements, can have an appreciable effect on deformation modes observed in thin films and on various aspects of crazing such as the craze stress and the craze fibril extension ratio. Examples of these effects will be presented and dis-... [Pg.71]

As the chain contour length between physical entanglements is reduced, so too is the maximum craze fibril extension ratio, Provided the entanglement network remains intact upon straining, X is given by... [Pg.82]

The chain contour length 1 between entanglements is given by le = lo Me/Mo... [Pg.32]

The IR rheooptical technique was applied to study the molecular processes that take place along the stress-strain curve of PET yams. The results indicate that the first modulus maximum marks the breakdown of the amorphous entanglement network and the start of molecular uncoiling by gauche-to-trans transitions. In addition, stress develops on the crystals and particularly on tie molecules with a short contour length in the amorphous domains. Ultimately, molecular fracture of taut-tie molecules (extended chains of polymers between crystals) causes the modulus to pass through a second... [Pg.31]

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