Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 8, pp. 1341−1344.
Pleiades Publishing, Ltd., 2010.
Original Russian Text
V.V. Tereshatov, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 8, pp. 1235−1238.
Inﬂ uence of Strong Bonding with Impenetrable Substrate
on Swelling of Elastomers
in Low-Molecular-Weight Liquids
V. V. Tereshatov
Institute of Technical Chemistry, Ural Division, Russian Academy of Sciences, Perm, Russia
Received February 27, 2010
Abstract—Swelling in various liquids was studied for a wide variety of free and bonded cross-linked polyurethane
materials with different structures and densities of three-dimensional network. A calculational method was proposed
for predicting the equilibrium swelling in liquids of elastic polymeric coatings bonded with a nonswelling substrate.
Articles manufactured from polymeric materials can
be used, according to their speciﬁ c chemical structure,
structural organization, and properties, under various
conditions, in particular, in contact with chemically inert
low-molecular-weight liquids (solvents or plasticizers).
The theory of mechanodiffusion transfer of liquids
in cross-linked elastomers suggests that the swelling
processes may differ signiﬁ cantly for an elastic polymeric
coating bonded with an impenetrable material (metal,
ceramics, etc) and unbonded (free) polymer [1, 2]. This
applies not only to the run of the kinetic swelling curves
but also to the degree of swelling of free and unbonded
elastomer samples. When a material layer is bonded
with a substrate (e.g., in the case of a polymeric coatings
on metal pipes or liquid storage vessels), an elastomer
may swell in only one, transverse, direction. This may
affect the amount of the liquid absorbed by the material.
The traditional approach to estimation of the limiting
liquid absorption by network elastomers is based on the
equilibrium swelling data for free (unbonded) samples.
Here, the inﬂ uence of strong bonding of elastomer on
its equilibrium swelling in chemically inert liquids was
examined. An approach was developed to prediction of
the limiting swelling of bonded cross-linked polymer
based on the equilibrium swelling data for free
This study was concerned with cross-linked
polyurethanes having different structural organizations
and densities of the three-dimensional network. This
choice was dictated by the fact that these compounds
allow variation of the density of not only the chemical
network but also the physical network with cross links,
domains of rigid blocks, resistant to many organic
liquids. The domain structure is characteristic for the so-
called segmented polyurethanes or polyurethaneureas
(SPUUs) with alternating soft segments and hard
(urethane or urethaneurea) blocks. A major difference
in polarity between the soft and hard blocks leads
to their microsegregation yielding cross links of a
speciﬁ c physical network of hard domains ranging from
5 to 30 nm in size , in which hydrogen bonds play
a cementing role.
Swelling of SPUUs was examined in a number of
organic liquids with individual and mixed polyether
segments based on oligo(diisocyanates) (prepolymers)
and their blends, as well as on polyurethane elastomers
(PUEs) which do not contain rigid block domains. The
elastomers were prepared by a two stage procedure.
A prepolymer based on oligo(propylene oxide)diol