New approach to the double melting peak of poly(l-lactic acid) observed by DSC

2012 ◽  
Vol 27 (10) ◽  
pp. 1379-1382 ◽  
Author(s):  
Carlos A. Gracia-Fernández ◽  
Silvia Gómez-Barreiro ◽  
Jorge López-Beceiro ◽  
Salvador Naya ◽  
Ramón Artiaga

Abstract

2012 ◽  
Vol 9 (3) ◽  
pp. 1569-1574 ◽  
Author(s):  
Yan-Hua Cai

Crystallization and melting behavior of Poly(L-lactic acid)(PLLA)/Talc composites with different talc content were investigated in detail. The addition of talc can increase the overall crystallization rate of PLLA, 5%talc makes the melt-crystallization peak temperature of PLLA increase from 96.28 °C to 105.22 °C, and the crystallization enthalpy increases from 1.379 J•g-1to 28.99 J•g-1. The melting behavior of PLLA/5%talc composites at a different heating rate during non-isothermal crystallization at different cooling rate shows that heating rate can affect the melting behavior of PLLA, with increasing of heating rate, the double melting peak degenerates to single melting peak. Melting behavior after isothermal crystallization and after cold isothermal crystallization and hot isothermal crystallization indicates that the double-melting peak of PLLA/5%talc composites results from melting-recrystallization.


2007 ◽  
Vol 18 (9) ◽  
pp. 1007-1014 ◽  
Author(s):  
Renaud de Tayrac ◽  
Marie-Claire Oliva-Lauraire ◽  
Isabelle Guiraud ◽  
Laurent Henry ◽  
Michel Vert ◽  
...  

2019 ◽  
Vol 34 (17) ◽  
pp. 2990-2999 ◽  
Author(s):  
Mingjing Chen ◽  
Juan Qiao ◽  
Xiaoxia Sun ◽  
Wenjuan Chen ◽  
Hiroshi Uyama ◽  
...  

Abstract


Author(s):  
F. W. J. Olver

In a recent paper (1) I described a method for the numerical evaluation of zeros of the Bessel functions Jn(z) and Yn(z), which was independent of computed values of these functions. The essence of the method was to regard the zeros ρ of the cylinder functionas a function of t and to solve numerically the third-order non-linear differential equation satisfied by ρ(t). It has since been successfully used to compute ten-decimal values of jn, s, yn, s, the sth positive zeros* of Jn(z), Yn(z) respectively, in the ranges n = 10 (1) 20, s = 1(1) 20. During the course of this work it was realized that the least satisfactory feature of the new method was the time taken for the evaluation of the first three or four zeros in comparison with that required for the higher zeros; the direct numerical technique for integrating the differential equation satisfied by ρ(t) becomes unwieldy for the small zeros and a different technique (described in the same paper) must be employed. It was also apparent that no mere refinement of the existing methods would remove this defect and that a new approach was required if it was to be eliminated. The outcome has been the development of the method to which the first part (§§ 2–6) of this paper is devoted.


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