XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
62
T1: O–20
Epoxy matrix with triaromatic mesogenic unit in dielectric
spectroscopy observations
Magdalena Włodarska
1
, Beata Mossety-Leszczak
2
, Grzegorz W. Bąk
1
,
Maciej Kisiel
2
, Maciej Dłużniewski
1
, and Lidia Okrasa
3
1
Institute of Physics, Technical University of Lodz, Wólczańska 219, 90-924 Łódź, Poland,
e-mail: magdaw@p.lodz.pl
2
Department of Industrial and Materials Chemistry, Rzeszow University of Technology, 35-959
Rzeszów, Poland
3
Department of Molecular Physics, Technical University of Lodz, Żeromskiego 116, 90-924 Łódź,
Poland
Liquid crystalline epoxy resins attract scientific interest thanks to their potential applications
in building advanced composites, which include matrices for nanoparticles aligned in one
preferred direction [1–4]. A distinctive property of the liquid crystalline epoxy resin selected for
this study is that it became possible to obtain a system with certain degree of macroscopic order
from that resin by choosing the curing conditions appropriately [4].
This work describes the properties of the final resin in terms of its dielectric response in a
wide range of temperature and frequency, interpreted by comparison to earlier results obtained
with other techniques. The properties of the final product differ substantially, depending on the
selection of the curing agent, type of the material and curing conditions. Dielectric spectroscopy
is very sensitive to changes in the molecular properties of the material, which makes it a good
tool for studying these properties, phase transitions or reaction progress. In most of the obtained
cured products, the collected dielectric data shows two relaxation processes. The α-process is
related to structural reorientation; it can usually be connected with the glass transition and the
mechanical properties of the material. The β-process can be identified with molecular motion –
probably associated with the carboxyl groups in the mesogen. This process was also observed in
the pure monomer, in the high temperature range: in the nematic phase it appeared at high
frequencies, and then at low frequencies in the solid phase. The dielectric measurements for
different mixtures also revealed differences in properties such as the glass transition temperature
and the fragility index between products cured with amines and with the carboxylic acid. The
obtained products were harder in the first case and more elastic in the other one. Another factor
that impacts the properties of the cured resin is the appropriate choice of the curing temperature.
As an example, curing with the acid at insufficient temperature yielded non-uniform products;
this is reflected in the dielectric spectroscopy results by an additional Maxwell-Wagner process
appearing at low frequencies. In such cases, post-curing in a higher temperature is necessary to
obtain a uniformly cured material.
Keywords: dielectric spectroscopy; polymer networks; liquid crystals; epoxy resins
Acknowledgment
The work was partially supported by the Polish Ministry of Science and Higher Education, Project Dz.St.
501/17-3-1-817.
References
[1] H. Galina, B. Mossety-Leszczak, J. Appl. Polym. Sci. 105 (2007) 224.
[2] B. Mossety-Leszczak, H. Galina, M. Włodarska, U. Szeluga, H. Maciejewski, Macromol. Symp. 291-
292 (2010) 127.
[3] B. Mossety-Leszczak, M. Włodarska, M. Kowalik, K. Łokaj, Macromol. Symp. 329 (2013) 193.
[4] B. Mossety-Leszczak, M. Wlodarska, Polym. Compos. 38(2) (2017) 277.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
63
T1: O–21
The effect of CaO-Al
2
O
3
-SiO
2
glasses composition on their structure
and reactivity in alkali activated system
Sylwia Kucharczyk
1
, Maciej Sitarz
1
, Maciej Zajac
2
, and Jan Deja
1
1
AGH University of Science and Technology, Krakow 30-059, Poland, e-mail: kuchar@agh.edu.pl
2
HeidelbergCement Technology Center GmbH, Leimen 69-181, Germany
The influence of calcium aluminosilicate glass chemical composition on resulting structure
and reactivity in ternary systems containing synthetic glass, limestone and alkali has been
explored. Chemical compositions of glasses are important especially when concerning chemistry
of Portland cement. Seven of them represent variability of chemical composition of siliceous
and calcareous fly ash glasses. Comparatively, one glass introduces granulated blast furnace slag
glass composition. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy
were employed to examine the structure of glasses. Reactivity was analyzed on paste samples
after 1, 2, 7, 28 and 90 days of curing by means of thermogravimetry (TG), X-ray diffraction
(XRD) and Fourier transform infrared spectroscopy (FTIR). Spectroscopic results confirm both
strong dependence of the structure on the chemical composition of glasses and their reactivity on
the degree of polymerization of the glass network. It has been shown that in presented systems
Al-rich glasses may exhibit reactivity at levels similar or even higher than Ca-rich glass. This
implies that Al present plays not only the role of a network-former but also a modifier when it
occurs in higher than tetrahedral coordination.
Keywords: Fourier transform infrared spectroscopy (FTIR); hydration; kinetics
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