Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 1, pp. 147−150.
Pleiades Publishing, Ltd., 2011.
Original Russian Text © V.Yu. Filatov, A.V. Murin, S.A. Kazienkov, S.V. Khitrin, S.L. Fuks, 2011, published in Zhurnal Prikladnoi Khimii, 2011, Vol. 84, No. 1,
AND POLYMERIC MATERIALS
Depolymerization of Polytetraﬂ uoroethylene
in the Presence of Water Vapor
or Fluorine-Transfer Agent
V. Yu. Filatov
, A. V. Murin
, S. A. Kazienkov
S. V. Khitrin
, and S. L. Fuks
Polymer Plant of Konstantinov Kirovo-Chepetsk Chemical Combine, Limited Liability Company,
Kirovo-Chepetsk, Kirov oblast, Russia
Vyatka State University, Kirov, Russia
Received February 11, 2010
Abstract—Relationships of depolymerization of polytetraﬂ uoroethylene wastes in the presence of water vapor
or a ﬂ uorine-transfer agent were studied. The possible ﬁ elds of application of the products formed (preparation of
composite coatings, lubricants, modifying additives to polymeric materials) were outlined.
Fluoropolymers exhibiting unique physicochemical
properties are widely used in modern engineering and are
the most valuable polymeric materials. The amount of
wastes of ﬂ uoropolymers, mainly polytetraﬂ uoroethylene
(PTFE), in Russia is estimated at hundreds thousands
tons. Their incineration is unacceptable because of
formation of highly toxic products such as carbonyl
diﬂ uoride, perﬂ uoroisobutylene, and hydrogen ﬂ uoride,
which are hazardous for the biosphere. One of the most
promising ways of secondary processing of ﬂ uoroplastic
wastes is their controlled thermal degradation [1–3]
under special conditions to monomers and other
In this study we examined the possibility of
regeneration of PTFE wastes by thermal degradation
with water vapor or a ﬂ uorine-transfer agent with the
aim to obtain ultradispersed PTFE (UPTFE) and also
ﬂ uorooleﬁ ns or perﬂ uoroparafﬁ ns.
It is known [4–6] that, when thermal degradation
of ﬂ uoroplastics is performed in the presence of water
vapor, highly toxic products are formed in considerably
smaller amounts. This procedure also prevents
overheating of reactor walls and reduces carbon black
formation, which improves the UPTFE characteristics.
The reactor containing PTFE wastes disintegrated
into 3–5-mm crumb was purged with nitrogen, after
which water vapor with the preset parameters was
fed until the release of gaseous products ceased. The
amounts of the unchanged PTFE (from the reactor)
and formed UPTFE (after ﬁ ltration and drying) were
Gaseous products were analyzed by GC–MS;
UPTFE, by IR spectroscopy, NMR, X-ray diffraction,
DSC, and electron microscopy.
The experimental results presented in Table 1 show
that the yield and composition of PTFE thermal degra-
dation products depend on temperature and ratio of wa-
ter vapor to PTFE crumb. As compared to optimal con-
ditions (run no. 1), an increase in temperature (run no 3)
and a decrease in the amount of water vapor (run nos. 3,
4) lead to a decrease in the UPTFE yield and an increase
in the yield of gaseous products. At the weight ratio of
water vapor to PTFE decreased to ~3 and temperature
increased to 650°С, UPTFE is not formed at all, and the
yield of gaseous products increases to 89.0%.
The results of analysis of gaseous products of
PTFE thermal degradation are given in Table 2.
Under all the conditions of thermal degradation in the