Determination of degree of crystallinity of Nylon 1212 by wide-angle X-ray diffraction

Based on the X-ray scattering intensity theory and using the approximate expression for the atomic scattering factor, the correction factors for three crystalline peaks and an amorphous peak of Nylon 1212 were calculated and the formula of degree of crystallinity of Nylon 1212 was derived by a graphic multipeak resolution method. The degree of crystallinity calculated from the WARD method is compatible with those obtained by density and calorimetry methods.

Multiple melting and crystallization behavior of nylon 1212

The wide-angle X-ray diffraction (WAXD) patterns of isothermally crystallized Nylon 1212 show that gamma-form crystals form below 90 degrees C and the alpha-form crystals call exist above 140 degrees C. In the temperature range of 90-140 degrees C, the a-form gamma-form crystals coexist. Variable-temperature WAXD exhibits that the nylon 1212 gamma-form does not show crystal and transition on heating, while a-form isothermally crystallized at 160 degrees C exhibits Brill transition at a little higher than 180 degrees C on heating. The multiple melting behaviors of Nylon 1212 isothermally crystallized from melt come from a complex mechanism of different crystal structures, dual lamellar population and melting-recrystallization. In polarized optical microscope (POM) observations, Nylon 1212 isothermally crystallized at 175 degrees C shows the ringed banded spherulites. However, at temperatures below 160 degrees C the ringed handed image disappears, and cross-extinct spherulites are formed.

Melting behaviors, isothermal and non-isothermal crystallization kinetics of nylon 1212

Isothermal crystallization, subsequent melting behavior and non-isothermal crystallization of nylon 1212 samples have been investigated in the temperature range of 160-171 degreesC using a differential scanning calorimeter (DSC). Subsequent DSC scans of isothermally crystallized samples exhibited three melting endotherms. The commonly used Avrami equation and that modified by Jeziorny were used, respectively, to fit the primary stage of isothermal and non-isothermal crystallizations of nylon 1212. The Avrami exponent n was evaluated, and was found to be in the range of 1.56-2.03 for isothermal crystallization, and of 2.38-3.05 for non-isothermal crystallization. The activation energies (DeltaE) were determined to be 284.5 KJ/mol and 102.63 KJ/mol, respectively, for the isothermal and non-isothermal crystallization processes by the Arrhenius' and the Kissinger's methods.

Literatura y acto: Aquiles, el regreso a la batalla

Greek literature was used from early times with educational purposes, Greek heroes presented were considered as paradigms to follow. However, human acts burst beyond reason and the stories told have little effect on the decisions of the receptor. The aim of this article is to review the character of Achilles in the Iliad, because for him to no avail gifts, friends, much less a narration by his preceptor Phoenix to depose his anger and return to the battlefield to assist his friends.

Dos combates : Batalla de Santa Isabel marzo 1º de 1866 , Los rifleros de China en el yerbaniz Santiago, Nuevo León marzo 1º de 1866

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Discurso pronunciado el día 20 de agosto de 1871 por el C. José María Lafragua, en conmemoración de la batalla de Churubusco

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Breve reseña de los sucesos de Guadalajara y de las Lomas de Calderón ; Diario de las operaciones y movimiento del ejército federal, después de la batalla de Silao,... Con un apéndice en que serefieren los sucesos de las lomas de San Miguelito y ocupación de la capital de la República.

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Batalla del 5 de mayo de 1862

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La batalla invisible

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De la batalla

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La batalla del 5 de mayo

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Batalla del 5 de mayo de 1862 en Puebla: telegramas oficiales..

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Campaña de Humayta: Pasaje del Río Paraná el 16 de abril de 1866, Batalla del Estero Ballaco el 2 de mayo de 1866, combate del paso Sidra el 20 de mayo de 1866, Batalla de Tuyuti el 24 de mayo de 1866

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Maquiavelo, comentado por N. Buonaparte: Manuscrito hallado en el coche de Buonaparte después de la Batalla del Monte San Juan, el 18 de junio de 1815

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Astérosismologie de l'étoile naine blanche variable GD 1212

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal