Chemistry Reference
In-Depth Information
FIGURE 7.5
The dependences of limiting draw ratio l on testing temperature
T
for PC (1,
2, 4) and PAr (3, 5). 1 - calculation according to the Eq. (5.7); 2, 3 - calculation according to
the Eq. (7.8); 4, 5 - the experimental data [32].
Hence, the stated results demonstrated undoubted profit of fractal analy-
sis application for polymer structure analytical description on molecular,
topological and supramolecular (suprasegmental) levels. These results cor-
respond completely to the made earlier assumptions (e.g., in Ref. [31]), but
the offered treatment allows precise qualitative personification of slowing
down of the chain in polymers in glassy state causes [32].
As it has been noted above, the main feature of polymers is that they con-
sist of long chain macromolecules. Therefore, it is to be expected that poly-
mer chains structure and their characteristics will be influenced essentially
on bulk polymers properties. One of such polymer chain structural factors is
availability in it of bulk side groups, which results to bulk polymers brittle-
ness enhancement [40]. A side groups effect on plasticity level for hetero-
chain polymers was considered in Ref. [41], where brittleness increase was
explained by side groups nonparticipation in local or macroscopic plasticity
processes.
In Ref. [42] for series of bromide-containing aromatic copolyethersul-
fones (B-PES) their high brittleness (the strain up to fracture ef
f
= 0.03 ÷
0.04) and low strength (fracture stress sf
f
= 29 ÷ 44 MPa) were found. One
of the causes of such low limiting characteristics for B-PES may be the
