The soft segment crystallinity and morphology of poly(ester-urethanes) (PEUs) based on poly(&-caprolactone) (PCL) as a soft
segment and an aliphatic diisocyanate in the hard segment were studied. It was found that the restriction of the crystallization
of the PCL soft segment depends on the hard segment concentration, the length of the soft segment, and the total molecular
mass of the PEUs. The PEU based on a low molecular mass PCL (M=2000) is an amorphous elastic material during a long time after
casting from solution or after melt crystallization. A soft-hard segment endothermal mixing transition (Tmix) of about 70-80C is observed in the DSC curves of this PEU sample.
Dynamic mechanical and thermal properties of poly(ester urethanes) (PEU) cross-linked with styrene have been studied. The
investigated polyurethanes were obtained from 4,4′-diphenylmethane diisocyanate and unsaturated oligo(alkyleneester)diol based
on cis-2-butene-1,4-diol. The conducted analyses dealt with the correlation between the chemical structure of poly(ester urethanes)
and their ability to phase separate as well as their thermal stability. The products of PEU thermal degradation were characterized
using infrared spectroscopy.
Effect of hydrolysis time on molar mass, glass transition temperature, crystallinity, and resistance to thermooxidation at
elevated temperatures was analyzed for Estanes 54600, 54610, and 54650. Kinetics of the hydrolysis can be plausibly described
in terms of the first-order reaction with an average induction period of about 7 days. Reduction of molar mass induced by
hydrolysis brings about an appreciable decrease in glass transition temperature, fraction of crystalline domains of soft segments,
and thermooxidative stability. The latter effect is manifested by shortening of the lifetimes (related to 5% mass loss) the
temperature dependence of which obeys the Arrhenius plot. The observed differences in hydrolysis resistance of Estanes can
be related to their chemical composition.
Authors:P. Šimon, Marta Fratričová, P. Schwarzer, and H.-W. Wilde
of poly(ester-urethanes), poly(ether-urethanes) and poly(acrylic-urethanes),
as a base for automotive paintings in interior applications, has been studied
by DSC. The samples were clearcoat and black-pigmented paints, unstabilized
and stabilized with HALS Tinuvin 292, UV absorber Tinuvin 1130 and antioxidant
Hostanox O3, exposed to weathering in Xenotest and in Arizona desert. From
the dependences of oxidation onset temperature on the heating rate, the kinetic
parameters enabling to calculate the oxidation induction time for a chosen
temperature have been obtained. From the values of oxidation induction time,
the protection factors of the additives and the residual stability of the
polymer after an ageing stress has been evaluated. It has been shown that
the equivalence between the two methods of weathering depends on the polymer
composition. A new criterion for the evaluation of synergism/antagonism of
additives in the stabilizing mixture has been proposed.