Authors:M. Mostafa, N. Afify, A. Gaber, and E. Abu Zaid
This work aims in studying the temperature dependence of the thermal properties (thermal diffusivity, k, specific heat, Cp and thermal conductivity, ) of some basalt group samples, collected from different regions in the eastern desert of Egypt. The thermal properties of these samples were measured in the temperature range from r.t. to 900 K. The average values of the thermal conductivity of these investigated samples lie in the range from 0.4·10–3 to 2.01·10–3 cal cm–1 s–1 K–1. This means that these samples are considered as thermal insulating materials. The thermogravimetric analysis (TG) confirmed that these investigated samples are dry rocks. X-ray fluorescence (XRF) and X-ray diffraction (XRD) confirmed that these rock samples have a crystalline phase, the peaks of XRD have a small change in their location as a result of heat treatment. This behaviour was attributed to the oxidation and firing of some minerals after the heat treatment.
Authors:Jerzy J. Chruściel, Grażyna Janowska, and Marzena Fejdyś
unmodified ammonium polyphosphate in a thermoplastic polyurethane composites [ 13 ].
In this article, we present the results of our studies concerning thermalproperties of the synthesized, new branched polymethylvinylborosiloxanes (PMVBSs) which have
Poly(lactic acid)/organo-montmorillonite nanocomposites were prepared by melt intercalation technique. Maleic anhydride-grafted
ethylene propylene rubber (EPMgMA) was added into the PLA/OMMT in order to improve the compatibility and toughness of the
nanocomposites. The samples were prepared by single screw extrusion followed by compression molding. The effect of OMMT and
EPMgMA on the thermal properties of PLA was studied. The thermal properties of the PLA/OMMT nanocomposites have been investigated
by using differential scanning calorimeter (DSC) and thermo-gravimetry analyzer (TG). The melting temperature (Tm), glass transition temperature (Tg), crystallization temperature (Tc), degree of crystallinity (χc), and thermal stability of the PLA/OMMT nanocomposites have been studied. It was found that the thermal properties of PLA
were greatly influenced by the addition of OMMT and EPMgMA.
DTA was used to study thermal properties and thermal stability of (50-x)Li2O-xTiO2-50P2O5 (x=0–10 mol%) and 45Li2Ot-yTiO2-(55-y)P2O5 (y=5–20 mol%) glasses. The addition of TiO2 to lithium phosphate glasses results in a non-linear increase of glass transition temperature. All prepared glasses crystallize
under heating within the temperature range of 400–540°C. The lowest tendency towards crystallization have the glasses with
x=7.5 and y=10 mol% TiO2. X-ray diffraction analysis showed that major compounds formed by annealing of the glasses were LiPO3, Li4 P2O7, TiP2O7 and NASICON-type LiTi2(PO4)3. DTA results also indicated that the maximum of nucleation rate for 45Li2O-5TiO2-50P2O5 glass is close to the glass transition temperature.
Thermal properties of recycled triphenylphosphite (TPP) chain extended poly(ethylene terephthalate) (PET) was investigated. As the TPP concentration increases, both reaction residues and molecular mass increase affecting significantly the thermal properties and crystallization behavior of the material. The presence of TPP residues did not affect the crystalline melt temperature (Tm), but modified the glass transition temperature (Tg), the crystallization temperature on heating (Thc) and the crystallization temperature on cooling (Tcc). In the samples submitted to extraction with acetone, the properties were influenced by molecular mass changes, probably due to the presence of some insoluble reaction residue. The thermal stability of the sample purified by extraction after chain extension was comparable to that of the non-extended sample when heating was carried out under nitrogen atmosphere.
Authors:Dongling Han, Longxiao Liu, and Xinghua Wang
The thermal properties of caprolactam/long chain lactam copolymer were studied with a Perkin-Elmer DSC 7. The melting point
(Tm), heat of fusion (δHm), crystalline degree (Xc), crystallization temperature (Tc) and glass transition temperature (Tg) of the copolymers increase with decrease of the content of the log chain lactam. From the changes in the mechanical properties
with corresponding changes in the thermal properties, it is clear that the copolymers are thermal plastic and elastic. In
addition, it is found that the results at a heating rate of 10 deg·min−1 are almost the same as that at 20 deg·min−1 after thermal history is erased.
Thermal properties of cis-1,4-poly(butadiene), Europrene cis, were investigated by means of thermal analysis and complementary methods. Thermal analysis of polymer was carried out both in air and inert atmosphere with a derivatgraph, DSC and internal TG-FTIR coupling system as well as internal TG, DTA-MS coupling system. It was found that investigations in air atmosphere the method of the sample preparation ofcis-1,4-poly(butadiene) influences the results of thermal analysis, which is connected with the rate oxygen diffusion into the reaction zone. Taking into consideration both the method of the sample preparing and atmosphere of thermal studies, the values of activation energy of destruction of cis-1,4-poly(butadiene) were determined. Using TG-FTIR and TG-MS methods, some products of thermal destruction of elastomer were determined.
Chemical compositions, crystalline structures and thermal properties of bombax cotton and natural colored cottons including
laurel green, bottle green and brown cotton were investigated by chemical analysis, SEM, IR spectra and X-ray diffraction.
The results showed that the crystallinity and crystallite sizes of laurel green cotton were lower than those of bottle green
cotton because of the excess content of suberin in the former. The crystallinity of brown cotton was similar to that of white
cotton, and bombax cotton had the lowest crystallinity but its crystallite orientation was the highest. Thermal property of
bottle green cotton was the most stable, whose decomposition temperature was higher of 30°C than that of common white cotton
because of its higher lignin content, and bombax cotton had the lowest thermal degradation temperature. But bottle green cotton
reached the highest decomposition speed and made decomposition finish within a very short time, and bombax cotton was just
Authors:Dong-Ho Rie, Sung-Woong Moon, and Kyung-Bum Lim
impossible [ 4 ].
Accordingly, the present research has performed basic research on a recycling possibility of building’s interior materials by analyzing combustion and thermalproperties according to flame retardant treatment of paper honeycomb and
Authors:D.-Y. Yang, Q.-X. Liu, X.-L. Xie, and F.-D. Zeng
The exfoliated poly(vinyl chloride) (PVC)/montmorillonite
(MMT) nanocomposites were synthesized by in situ intercalated polymerization
of vinyl chloride (VC) in the presence of organic-intercalated montmorillonite
(OMMT). Their structures and thermal properties were characterized. The results
showed that layered silicates are well exfoliated and uniformly distributed
in PVC matrix during in situ intercalated polymerization of VC in the presence
of OMMT. The glass transition temperatures of PVC phases in the PVC/MMT nanocomposites
are all lower than that of pristine PVC due to the incorporation of the exfoliated
silicate layers in PVC matrix. The 5% mass loss temperature (T5%),
the dehydrochlorination temperature (Tmax1)
of the PVC matrix decreased due to the free and interlayer water in MMT, the
low thermal stability, and the enhanced dehydrochlorination of the PVC matrix
by alkyl ammonium pre-treated MMT. However, the thermal decomposition temperature
of the dehydrochlorinated PVC (Tmax2)
and char at 600C are slightly increased in the presence of silicate layers.