Browsing by Author "Fares, M. M."

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Open Access
Analysis of polymers using evolved-gas and direct-pyrolysis techniques
(Royal Society of Chemistry, 1994) Fares, M. M.; Yalcin, T.; Hacaloglu, J.; Gungor, A.; Süzer, Şefik
Thermal analysis of polystyrene, poly(p-methylstyrene) and poly(α-methylstyrene) has been carried out using evolved-gas analysis by infrared and mass spectrometry, and direct-pyrolysis analysis by mass spectrometric techniques. Evolved-gas analysis, both by infrared and mass spectrometry, reveals features due mainly to the corresponding monomers or stable, volatile, and low relative molecular mass degradation products. In direct-pyrolysis mass spectrometry, however, primary decomposition products and heavier fragments such as dimers and trimers can also be detected. The ion-temperature profiles of the corresponding monomer ions reveal information about the thermal stability of the polymers.
Open Access
Characterization of degradation products of polyethylene oxide by pyrolysis mass spectrometry
(Pergamon Press, 1994) Fares, M. M.; Hacaloglu, J.; Süzer, Şefik
The techniques of direct and indirect (evolved gas analysis) pyrolysis MS are used to characterize the thermal degradation products of polyethylene oxide. Using direct pyrolysis MS technique the main degradation process is determined to be due to CO and CC scissions yielding fragments characteristic of the polymer. Evolved gas analysis indicates formation of small molecular stable compounds such as C2H5OC2H5, CH3CHO, CO2, CO and C2H4. © 1994.
Open Access
Pyrolysis mass spectrometric analysis of styrene-butadiene block and random copolymers
(Elsevier, 1997-02) Hacaloglu, J.; Ersen, T.; Ertugrul, N.; Fares, M. M.; Süzer, Şefik
Direct pyrolysis mass spectrometric analysis of a styrene-butadiene-styrene block copolymer indicated that thermal decomposition of each block shows a resemblance to the related homopolymer, giving a possibility of differentiation of blocks. However, the random analog, the styrene butadiene rubber, degraded in a manner that is somewhat in between in nature of the thermal characteristics of both homopolymers. This technique shows promise to differentiate thermal behaviors of each sequence in block polymers if any exist. Indirect pyrolysis mass spectrometric analysis gave no clear evidence for differentiation of the nature and the composition of the copolymers. © 1997 Elsevier Science Ltd. All rights reserved.
Open Access
Pyrolysis mass spectrometric analysis of styrene-isoprene-styrene copolymers
(Elsevier, 1999-05) Hacaloglu, J.; Fares, M. M.; Süzer, Şefik
Thermal analysis of styrene±isoprene±styrene block copolymer, using the direct pyrolysis mass spectrometry (MS) technique, indicated that each block showed very similar thermal behavior with the corresponding homopolymer. The isoprene block was found to be thermally less stable, decomposing by random scissions followed by cyclization reactions. The more stable styrene block degraded by a radical depolymerization mechanism. With an indirect pyrolysis MS technique, it was found that production of benzene, toluene, 1-methyl cyclopentene and 1-methyl cyclohexene was more e ective when degradation was carried out in a closed reactor. # 1999 Elsevier Science Ltd. All rights reserved.