Extended amorphous chains

Polymers Elastomers (rubbers) Soft plastics (e.g. low density PE) Isotropic hard plastics ( Amorphous [ Semi-crystalline Conventional fibres (nylon, PETP) "Extended chain" fibres (Extended zig-zag chains (Extended helical chains ( Glassy. Cross-linked (Tg < 275 K lTg> 325 K 0.001 0.2 2.5- 3 2.5- 5 1-3 3 5-15 250fl ca 50fl... [Pg.732]

It is certain that the relaxation behavior of filled rubbers at large strains involves numerous complications beyond the phenomena of linear viscoelasticity in unfilled amorphous polymers. Breakdown of filler structure, strain amplification, failure of the polymer-filler bond, scission of highly extended network chains and changes in network chain configuration probably all play important roles in certain ranges of time, strain rate, and temperature. A clear understanding of the interplay of these effects is not yet at hand. [Pg.206]

Fig. 10. Sketch of the transformations of the oriented chains during deformation, in-between are additional amorphous chains a) lamellae with some tie-molecules, b) elastic shear-deformation of lamellae imder small load and reorientation with respect to the load, c) fracture of lamellae into smaller blocks due to local stress concentration caused by tie molecules, d) stretched aligned, but not re-crystallised chains between the blocks during stretching at higher temperatures, e) some of the fibrillar arranged molecules crystallise, final stage in the case of hot stretched iPP, f) further dissolution of the blocks creating more extended chains at room temperature, g) finally, there are several strands of extended chains, not crystallised, with some amorphous regions in between, final stage in the case of cold stretched rPP.

$Fig. 10. Sketch of the transformations of the oriented chains during deformation, in-between are additional amorphous chains a) lamellae with some tie-molecules, b) elastic shear-deformation of lamellae imder small load and reorientation with respect to the load, c) fracture of lamellae into smaller blocks due to local stress concentration caused by tie molecules, d) stretched aligned, but not re-crystallised chains between the blocks during stretching at higher temperatures, e) some of the fibrillar arranged molecules crystallise, final stage in the case of hot stretched iPP, f) further dissolution of the blocks creating more extended chains at room temperature, g) finally, there are several strands of extended chains, not crystallised, with some amorphous regions in between, final stage in the case of cold stretched rPP.$

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