Crystallization kinetics and melting behaviour of oriented natural rubber

2008 ◽  
pp. 267-274 ◽  
Author(s):  
W. Sietz ◽  
D. Göritz ◽  
F. H. Müller
Keyword(s):  
Natural Rubber ◽  
Crystallization Kinetics ◽  
Melting Behaviour

Effect of Deformation on the Crystallization of Supercooled Cured and Uncured Rubbers

1964 ◽  
Vol 37 (2) ◽  
pp. 404-407 ◽  
Author(s):  
M. F. Bukhina
Keyword(s):  
General Theory ◽  
Natural Rubber ◽  
Mechanical Stress ◽  
Melting Temperature ◽  
Crystallization Kinetics ◽  
Crystallization Rate ◽  
Approximate Expression ◽  
Supercooled Liquids ◽  
Half Time ◽  
Equilibrium Melting Temperature

Abstract 1. The dependence of the polymer crystallization rates on temperature is considered on the basis of the general theory of crystallization kinetics for supercooled liquids. The coefficients in the equations relating the crystallization half time, τ½, to the degree of supercooling are calculated for natural rubber. 2. An approximate expression is obtained which relates the equilibrium melting temperature of deformed rubber with the mechanical stress applied when crystallization starts. 3. The acceleration of crystallization which is induced by deformation is shown to be basically associated with an increase of the equilibrium melting temperature. 4. The possibility of calculating the crystallization rate at all temperatures and stresses from the results of a small number of experiments is established.

Crystallization kinetics and melting behaviour of microbial poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

2005 ◽  
Vol 54 (7) ◽  
pp. 1055-1064 ◽  
Author(s):  
Cheng Chen ◽  
Man Ken Cheung ◽  
Peter HF Yu
Keyword(s):  
Crystallization Kinetics ◽  
Melting Behaviour

Crystallization kinetics of biaxially stretched natural rubber

1973 ◽  
Vol 11 (8) ◽  
pp. 1477-1488 ◽  
Author(s):  
Ryo Oono ◽  
Keizo Miyasaka ◽  
Kinzo Ishikawa
Keyword(s):  
Natural Rubber ◽  
Crystallization Kinetics ◽  
Kinetics Of

scholarly journals Memory effect in melting behaviour, crystallization kinetics and morphology of poly(propylene terephthalate)

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Laura Sisti ◽  
Lara Finelli ◽  
Nadia Lotti ◽  
Corrado Berti ◽  
Andrea Munari
Keyword(s):  
Thermal Treatment ◽  
Optical Microscopy ◽  
Melting Temperature ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Crystallization Process ◽  
Nucleation Theory ◽  
Melting Behaviour ◽  
Non Linear ◽  
Poly Propylene

AbstractCrystallization kinetics and melting behaviour of poly(propylene terephthalate) (PPT) were investigated by means of differential scanning calorimetry and hot-stage optical microscopy. Isothermal crystallization kinetics was analysed according to the Avrami treatment. The effects of temperature and duration of melting on the overall rate of isothermal crystallization were studied: the rate was found to decrease with increasing melting temperature and melting time. This result was discussed on the basis of the gradual destruction of predetermined athermal nuclei. Values of the Avrami exponent close to 3 were obtained, regardless of the adopted thermal treatment and the crystallization temperature, Tc, in agreement with a crystallization process originating from predetermined nuclei and characterized by three-dimensional spherulitic growth. As a matter of fact, spacefilling spherulites were observed by optical microscopy at all Tc’s, independent of the applied thermal treatments. For each of them, the rate of crystallization became lower as Tc increased, as usual at low undercooling where the crystallization process is controlled by nucleation. The observed multiple endotherms, which are commonly displayed by polyesters, were influenced by Tc and ascribed to melting and recrystallization processes. Linear and non-linear treatments were applied in order to estimate the equilibrium melting temperature for PPT, by using the corrected melting temperatures. The non-linear estimation yielded an about 33°C higher value with respect to the one obtained by means of the linear approach. Through the analysis of secondary nucleation theory, the classical II→III transition was found to occur at a temperature of 194°C. The average work of chain folding for nucleation was determined to be c. 5.2 kcal/mol. The heat of fusion was correlated to the specific heat increment for samples with different degree of crystallinity and the results were interpreted on the basis of the existence of an interphase, whose amount was found to depend on the thermal treatment the polymer was subjected to.

Effect of Hydrostatic Pressures on the Crystallization Kinetics of Natural Rubber

1963 ◽  
Vol 34 (8) ◽  
pp. 2312-2317 ◽  
Author(s):  
Gordon M. Martin ◽  
Leo Mandelkern
Keyword(s):  
Natural Rubber ◽  
Crystallization Kinetics ◽  
Kinetics Of
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