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Abstract  

The melting behavior and the crystallization kinetics of poly(butylene terephthalate/thiodiethylene terephthalate) copolymers were investigated by DSC technique. The multiple endotherms were influenced both by T c and composition. By applying the Hoffman—Weeks' method, T m 0 the of the copolymers was derived. The isothermal crystallization kinetics was analyzed according to the Avrami's treatment. Values of the exponent n close to 3 were obtained, independently of T c and composition. The introduction of thiodiethylene terephthalate units decreased the PBT crystallization rate. H m was correlated to c p for samples with different degree of crystallinity and the results were interpreted on the basis of the existence of an interphase.

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interaction between particles and polymer matrix, and then influences the crystallization and melting behavior of polymer composites. It is found that nano-CaCO 3 particles treated with nonionic modifier increased the crystallization rate of PP matrix [ 11

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]. Here, we attempted to research the nucleation effect of TMB-5 on crystallization of PP-MA. The β-crystallization tendency of PP-MA has been reported recently [ 15 ]. Isothermal and nonisothermal crystallization behaviors and subsequent melting behaviors

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phase, the so called “rigid-amorphous phase” (RAP) or “inter-phase” between crystalline and amorphous layers has to be taken into consideration in these structures. In this view, herein the melting behavior and the isothermal crystallization kinetics of

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isothermal crystallization and melting behavior of WF/PP composites, especially in the presence of m -TMI- g -PP. Therefore, fundamental studies on the effect of the presence of WF and with m -TMI- g -PP as a compatibilizer on the crystallization and

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Abstract  

Fish oil which is characterised by important amounts of poly-unsaturated ω-3 fatty acids attach increasing importance within functional foods. Recently attention is directed on physical methods that allow fast and relatively easy the identification and discrimination of oils. DSC measurements yield in information on thermal effects, characterised by changes in enthalpy and their temperature range such as melting and crystallisation. The aim of the investigation presented here was to take DSC curves in the temperature range +20 to −40°C on several fish oils and fish oil capsules to visualise the crystallisation and melting behaviour and to compare transition temperatures and enthalpies.

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Abstract  

Using temperature-modulated differential scanning calorimetry, the melting behaviour of poly(oxytetramethylene)-alt-(aromatic oligoamide) (POTM-alt-AOA) has been studied in comparison with that of polyoxytetramethylene glycohols (POTMGs). The apparent melting temperature of the block copolymers is found to be less than that of the corresponding POTMGs by approximately 30°C. The relaxation time of melting of a POTM segment has been estimated and compared with that of POTMG. The relaxation time of POTM-alt-AOA is slightly shorter than that of POTMG when the molar mass of the POTM segment is 2900; however, it is longer when the molar mass is 1400.

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Abstract  

In this paper we present our recent positron annihilation study of the liquid»solid phase boundary for CO2 confined in nanometer pores of VYCOR glass. We find that CO2 remains liquid in the pores far below the bulk freezing temperature and there is pronounced hysteresis between freezing and melting compared to that seen at the gas-liquid boundary in the pores. On freezing we see evidence of open space created in the pores. This leads to complex melting behaviour possibly involving the formation of gas-liquid interfaces. We see that frezing in the pores is totally irreversible, so that any solid which forms (no matter how small) remains stable up to the higher melting temperature. In contrast melting is more reversible (possibly indicating nucleation centres which permit immediate re-freezing). Finally, the pre-frozen state in the pores is different to the post-melted state.

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Abstract  

Two enantiomeric forms of xylose were identified as α-D-xylopyranose and α-L-xylopyranose by powder diffraction. Their melting behaviour was studied with conventional DSC and StepScan DSC method, the decomposition was studied with TG and evolved gases were analyzed with combined TG-FTIR technique. The measurements were performed at different heating rates. The decomposition of xylose samples took place in four steps and the main evolved gases were H2O, CO2 and furans. The initial temperature of TG measurements and the onset and peak temperatures of DSC measurements were moved to higher temperatures as heating rates were increased. The decomposition of L-xylose started at slightly higher temperatures than that of D-xylose and L-xylose melted at higher temperatures than D-xylose. The differences were more obvious at low heating rates. There were also differences in the melting temperatures among different samples of the same sugar. The StepScan measurements showed that the kinetic part of melting was considerable. The melting of xylose was anomalous because, besides the melting, also partial thermal decomposition and mutarotation occurred. The melting points are affected by both the method of determination and the origin and quality of samples. Melting point analysis with a standardized method appears to be a good measure of the quality of crystalline xylose. However, the melting point alone cannot be used for the identification of xylose samples in all cases.

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