Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 7, pp. 1324−1325.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
R.Yu. Golovanov, V.P. Barannikov, K.V. Pochivalov, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 7,
Melting of Polyoleﬁ ns in Presence of Liquids
R. Yu. Golovanov, V. P. Barannikov, and K. V. Pochivalov
Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russia
Received March 30, 2009
Abstract—The existence of a section with a constant melting point in the curve of melting polyolefins in presence
of a liquid was confirmed experimentally by the method of differential scanning calorimetry.
Earlier [1, 2] the examination of special features
of the processes of melting and formation of polymer
crystallites allowed us to substantiate the viewpoint,
according to which in the phase diagram of unrestrictedly
mixing systems amorphous-crystalline polymer–liquid
(see the ﬁ gure) there is a section inside which the melting
of the polymer is independent of the high-
molecular component content ω
. In other words, if the
initial heterogeneous mixtures contains ω
or more mass
fractions of a liquid, the polymer becomes completely
amorphous at the same temperature.
This viewpoint is supported by the differential
scanning calorimetry data.
Subjects of the study were: low-density polyethylene
(LDP) 15803-020-grade with melting point of 110.6 ±
0.5°C, density of 0.920 g cm
at 25°C (determined by
the floatation method), and melt index of 1.32 ±
0.05 g/10 min; polypropylene (PP) (technical speciﬁ cations
2211-015-00203521-99) with melting point of 168.7 ±
0.5°C, density of 0.906 ± 0.001 g cm
at 25°C, and melt
index of 1.29 g/10 min; chemically pure-grade toluene
and o-xylene. The densities and refraction indexes of
those latter estimated on a DMA-4500 densitometer and
an IRF-454B2M refractometer corresponded to reference
Phase diagram of the system amorphous-crystalline
polymer–liquid (scheme). Curves: АВС: melting of last
crystallites of a polymer, BD: solubility of a liquid in a poly-
mer. Areas: (I) single-phase system (molecular mixture of
a liquid and a polymer free from net sites in the form of
crystallites), (II) single-phase system−solution of a liquid
in an amorphous-crystalline polymer (gel), (III) two-phase
system (pure liquid + solution of a liquid in an amorphous-
crystalline polymer). Explanations in the text.
Melting points of polyoleﬁ ns at various contents of
a polymeric component in a system