The polycondensation reactions between 4,4′-[sulphonyl bis(p-benzoyl)(p-phenyleneoxy)]dibenzoic acid (I) andp-phenylenediamine (II), 1,5-diaminonaphthalene (III), 4,4′-sulphonyldianiline (IV), 4,4′-diaminodiphenylsulphide (V) 4,4′-methylenedianiline
(VI) and 4,4′-oxydianiline (VII) to form aromatic polyamides containing sulphone, ether and ketone linkages were attempted
by a solid-solid interaction route. A stoichiometric 1∶1 molar ratio of solid reactants was dynamically heated directly in
a TG/DSC apparatus, and simultaneous TG/FT-IR was performed to interpret the mechanism of reaction. The results suggest that
the polycondensation is dependent on the diamine used. The formation of polyamide was successful when I interacted with II,
III, VI and VII. The interaction with IV and V was in part successful because partial decarboxylation of the diacid, made
unstable by the diamine, occurred before the condensation reaction.
Authors:L. Abate, I. Blanco, A. Pappalardo and A. Pollicino
The degradation of a new thermoplastic poly(arylene)ether copolymer was carried out in both dynamic and isothermal heating
conditions, under nitrogen flow and in a static air atmosphere. The measurements showed that the copolymer degraded through
two stages in both investigated environments with the formation of a stable residue in N2 and complete mass loss in air. The apparent activation energy values associated with the degradation processes were evaluated.
The obtained results suggested different degradation mechanisms between N2and air. Results were discussed and compared with those obtained for several polymers previously investigated.
Authors:L. Abate, I. Blanco, F. Bottino, G. Di Pasquale, E. Fabbri, A. Orestano and A. Pollicino
Styrene and montmorillonite organically modified with imidazolium surfactants (MMT) at various alkyl chain lengths (C12, C16 and C18) were used to prepare the corresponding PS/MMT/C12, PS/MMT/C16 and PS/MMT/C18 nanocomposites by in situ polymerization. XRD and TEM analyses evidenced the formation of both intercalated and exfoliated structures. The glass transition
temperatures (Tg) of nanocomposites, as well as that of neat PS, were obtained by DSC measurements. The thermal degradations were carried
out in the scanning mode, in both inert and oxidative environments, and the initial temperatures of decomposition (Ti) and the apparent activation energies of degradation (Ea) were determined. Due to an oxidative degradation mechanism, the Ti and Ea values in air atmosphere were lower than those under nitrogen.
The results indicated that nanocomposites are more thermally stable than polystyrene, and suggested an increasing degree of
exfoliation as a function of alkyl chain length of surfactant, associated with enhancing thermal stability.
Authors:S. Čuvanová, M. Reháková, Z. Bastl, A. Pollicino, S. Nagyová and V. Fajnor
properties of two kinds of composite material of synthetic zeolite ZSM5 in
potassium form (K-ZSM5) with AgI have been studied. The composites have been
prepared by treating the silver form of synthetic zeolite ZSM5 (Ag-ZSM5) with
potassium iodide solution under different experimental conditions. One of
the composites was additionally sintered at temperature 500C for 20 h.
Both composites have been characterized by TG, DTG, DTA, EDS analysis, X-ray
powder diffractometry and X-ray photoelectron spectroscopy. The methods of
thermal analysis as well as X-ray powder diffractometry and XPS confirmed
the differences between the two composites caused by sintering during the
synthesis. The content of AgI in the surface layer was different. No changes
of the zeolitic mineral dimensions are observed.