Chemistry Reference
In-Depth Information
Synthesis of PETP was carried out with additives HC-1-HC-7 in the amount of 1 mass %.
Additives were introduced in the form of suspension in ethyleneglycol at the beginning of the
process of peretherification.
Synthesized polymers were uniformly dyed into proper colours, intrinsic viscosity was in
the region 0,66-0,77 while the same index for colourless PETP, obtained under the same
conditions, was 0,62, that also corresponds to technological parameters.
The process of fibres forming, containing additives HC-1 - HC-7 was stable and there
were no difficulties at drafting. Being obtained fibres were drawing easily, they had the same
thickness along the whole length and there were no any swellings and non-uniformities. Fibre
breaks during formation appeared seldom. Here one may come to a conclusion that
introduction of hexaazocyclanes did not influence the process of formation and so
introduction of these compounds into reaction mass does not practically influence fibre-
forming properties of PETP.
Miscibility of additives being used with polymer and uniformity of obtained polymer
were controlled by comparison of spectra of hexaazocyclanes solutions absorption in cresol
and solutions of dyed fibres before and after spinneret (Figure 3.3). Spectra practically
coincide with each other, showing full solution of dye and good homogenization of polymer
melt.
Hexaazocyclanes, depending on concentration, dye polymer from yellow up to brown
colour. It is characteristic that at the concentration of the additive 1% of the mass polymer
becomes bright coloured. Correlation of conditions for obtaining initial and dyed PETP fibres
has shown that introduction of HC-1 - HC-7 into PETP melt in the amounts from 0,5 to 1%
does not decline the rate of fibre forming, does not cause their adhesiveness, fragility and
early solidification. This is undoubted advantage of suggested additives as many substances,
being potentially dyes, cannot be used as they are not compatible with technological
processes of producing PETP-fibres.
In order to understand special features of additives effect on microcrystalline polymer
structure it is necessary to pay attention to features of the structure of PETP - polymer blocks.
Polymer, as solid, has imperfect supermolecular structure; it has amorphous regions,
regions without structures and crystalline regions with well packed macromolecules. Lamellar
monocrystals (lamellae) in which macromolecules are placed perpendicular to wide surface of
a plate are the main structure of polymer crystalline part. Usually length of macromolecule
being crystallized greatly exceeds thickness of lamella and, to be placed into the crystal,
macromolecule must repeatedly fold.
PETP crystallizes easily, moreover in the work [129] it has been shown that PETP
crystallization takes place at the expense of transformation of groups -O-CH2-CH2-O into
transconfiguration:
CH
2
O
CH
O
2
Probably it is easier for PETP molecule to fold in order to be packed into crystal. Since
PETP is produced from the melt then packing of macromolecules into crystal occurs
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