Effect of composition and polyesterification catalysts on the optical properties of cured polyesters

Simitzis, J.; Zoumpoulakis, L.; Soulis, Spyridon

doi:10.1002/pi.825

Cited by 7 publications

(16 citation statements)

References 15 publications

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“…These results showed that the C CH 3 groups were degraded. Two prominent peaks are also revealed at wavelengths of 1659 and 1720 cm −1 , which represent the stretching vibrations of olefinic (C C) and carbonyl (C O) groups that can be produced by generation of free radicals (such as • CH 3 ) in presence of oxygen [35,37]. The C C and C O groups belong to the chromophoric groups, which tend to absorb the light by exciting an electron from their ground state into an excited state when exposed to UV radiation.…”

Section: Analysis Of Photo-oxidationmentioning

confidence: 98%

Improving the UV degradation resistance of epoxy coatings using modified carbon black nanoparticles

Ghasemi-Kahrizsangi¹,

Neshati²,

Shariatpanahi³

et al. 2015

Progress in Organic Coatings

121

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Section: Analysis Of Photo-oxidationmentioning

confidence: 98%

Improving the UV degradation resistance of epoxy coatings using modified carbon black nanoparticles

Ghasemi-Kahrizsangi¹,

Neshati²,

Shariatpanahi³

et al. 2015

Progress in Organic Coatings

121

View full text Add to dashboard Cite

“…Figures 4 and 5 show the spectra from all the examined composites, while the main peaks of each kind of pure polyester are listed in Table 3. All the basic characteristic peaks related to polyesters according to the literature [23][24][25][35][36][37][38][39][40][41] are present and detectable in the spectra of both kinds of polyesters. The symbols used for the identification of each peak, can be explained as follows: i) regarding the shape of the peak: (sh) means sharp and (br) means broad, ii) regarding the magnitude of the peak: (s) means strong, (m) means medium, (w) means weak and (pl) means plateau.…”

Section: Infra Red Spectroscopy Via Fourier Transformation (Ft-ir) Chmentioning

confidence: 99%

“…These monomers were used with ethylene glycol with 10% molar excess over stoichiometry, because of the fact that ethylene glycol evaporates during the reaction. Toluene was used as a reflux fluid (3.5% v/w of total monomers) and hydroquinone was employed as inhibitor (0.013% w/w of total monomers) [23][24][25]. The product of the polymerization was the development of the laboratory unsaturated polyester with the code type MA6AA4.…”

Section: Experimental 21 Laboratory Unsaturated Polyestermentioning

confidence: 99%

“…Measurements of the generated water quantities versus time, lead to the determination of such stages of the polymerization. So as a consequence, Acid Number (AN) of the final product was determined by titration with 0.5N methanolic potassium hydroxide solution and calculated 44 mgKOH/g polyester, which is an accepted value according to literature [23,24]. Not only Acid Number but also other kinetic parameters, regarding polymerization process, have been calculated and are exposed in Table 1 (theoretical background is not referred here, as it is thoroughly explained in other works) [23][24][25].…”

mentioning

confidence: 99%

“…Afterwards liquid/ solid mixtures (cured system) were prepared by mixing polyester (either commercial polyester type: thixotropic polyester with accelerator, Neotex, Athens, Greece or laboratory-MA6AA4 one), barium titanate nano-particles (Sigma Aldrich, Taufkirchen, Germany) (with mean diameter in the range: 30-50 nm), methyl ethyl ketone peroxide (MEKP) as initiator and cobalt (II) naphthenate (CoNp) as accelerator. The proportion of MEKP was 3% v/w and CoNp was 1% v/w (both proportions are referred on polyester's quantity) [23][24][25]. The specimen's content in barium titanate ranged from 0-20% w/w.…”

mentioning

confidence: 99%

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Barium titanate/polyester resin nanocomposites: Development, structure-properties relationship and energy storage capability

Asimakopoulos¹,

Psarras²,

Zoumpoulakis³

2014

Express Polym. Lett.

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Abstract. Nanocomposite materials based on two different types of polyester matrix (a commercial type and a laboratory produced one) with embedded barium titanate nano-particles were developed and characterized. Structural and morphological characteristics of the produced composite specimens were studied via X-ray diffraction, Fourier transformation infra red spectroscopy, and scanning electron microscopy. Thermal, mechanical and electrical performance was examined via differential scanning calorimetry, bending and shear strength tests, and broadband dielectric spectroscopy, respectively. Mechanical strength appears to reduce with the increase of filler content. Commercial polyester's composites exhibit brittle behaviour, while laboratory polyester's composites exhibit an elastomeric performance. Dielectric data reveal the presence of four relaxation processes, which are attributed to motion of small parts of the polymer chain (!-mode), re-arrangement of polar side groups ("-mode), glass to rubber transition of the polymer matrix (#-mode) and Interfacial Polarization between the systems' constituents. Finally, the energy storing efficiency of the systems was examined by calculating the density of energy. Vol.8, No.9 (2014) 692-707 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2014.72 * Corresponding author, e-mail: G.C.Psarras@upatras.gr © BME-PT An outstanding position in the group of electroceramics is given to composite materials based on barium titanate. Barium titanate is a wide band gap semiconductive ferroelectric material with perovskite structure which has been of practical importance for over 60 years due to its specific electrical properties. Barium titanate's great significance is expressed in its applications, which include ceramic capacitors, PTCR thermistors (positive temperature coefficient resistors/thermistors or posistors), piezoelectric sensors, optoelectronic devices, transducers, actuators etc. [4][5][6][7][8][9][10]. Furthermore, it is being applied as a capacitive material in dynamic random access memories (DRAM) in integrated circuits. DRAM applications require both high dielectric constant and good insulating properties [10]. Semiconductor memories such as dynamic random access memories (DRAM's) and static random access memories (SRAM's) currently dominate the market. However, the disadvantage of these memories is that they are volatile, i.e. the stored information is lost when the power fails. The non-volatile memories available at this time include complementary metal oxide semiconductors (CMOS) with battery backup and electrically erasable read only memories (EEPROM's). These non-volatile memories are very expensive. The main advantages offered by ferroelectric random access memories (FRAM's) include non-volatility and radiation hardened compatibility with CMOS and GaAs circuitry, high speed (30ns cycle time for read/erase/rewrite) and high density (4 (µm) 2 /cell size) [11]. Up to now, the most important utility of BaTiO 3 / polymer composites is ...

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Influence of backbone rigidity on the curing and the dielectric relaxations of unsaturated polyesters

Simitzis

Triantou

Soulis

et al. 2010

J of Applied Polymer Sci

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Unsaturated polyesters with maleic acid and different molar ratio of phthalic anhydride to adipic acid were produced, mixed with styrene, and cured. The degree of double bonds conversion, determined by differential scanning calorimetry (a DSC ), indicating the initial curing, increases significantly with the molar ratio of phthalic anhydride. On the other hand, the degree of double bonds conversion of maleate (a UP,FTIR ) and styrene (a St,FTIR ) units determined by Fourier transform infrared spectroscopy after prolonged curing are considerably higher than a DSC and increase slightly with the molar ratio of phthalic anhydride. Polyester containing phthalic anhydride without adipic acid (M5P5) has the lowest tetrahydrofuran uptake and diffusion parameter D/a 2 due to its more rigid segments, in opposite to polyester containing adipic acid (M5A5) having the highest values. According to dielectric spectroscopy measurements, two different relaxations were determined, one beginning above 130 C (with peak above 180 C) attributed to arelaxation (dielectric glass transition) and a second one at lower temperatures, attributed to b-relaxation. The peak of b-relaxation is at around 130, 75-80, and 30 C for the rigid, intermediate rigidity/flexibility, and flexible polyesters, respectively. The a-relaxation is determined at low frequencies and the b-relaxation at intermediate or high frequencies.

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Effect of composition and polyesterification catalysts on the optical properties of cured polyesters

Cited by 7 publications

References 15 publications

Improving the UV degradation resistance of epoxy coatings using modified carbon black nanoparticles

Improving the UV degradation resistance of epoxy coatings using modified carbon black nanoparticles

Barium titanate/polyester resin nanocomposites: Development, structure-properties relationship and energy storage capability

Influence of backbone rigidity on the curing and the dielectric relaxations of unsaturated polyesters

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