scholarly journals Nanofeatures affect the thermal transitions of polymer thin films: a microcantilever-based investigation

2020 ◽  
Vol 1 (6) ◽  
pp. 2084-2094 ◽  
Author(s):  
Maximilien Lopes-Rodrigues ◽  
Didac Martí-Balleste ◽  
Catherine Michaux ◽  
Eric A. Perpète ◽  
Jordi Puiggalí ◽  
...  
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Crystallization Temperature ◽  
Polymer Thin Films ◽  
Cold Crystallization ◽  
Thermal Transitions

Microcantilever-based technology has been used to study the influence of nanofeatures (i.e. nanopores, nanoperforations and segregated drug nanodomains) on the glass transition temperature and the cold crystallization temperature of PLA thin films.

Impact of Surface-Modified Nanoparticles on Glass Transition Temperature and Elastic Modulus of Polymer Thin Films

2007 ◽  
Vol 40 (22) ◽  
pp. 7755-7757 ◽  
Author(s):  
Jong-Young Lee ◽  
Kristin E. Su ◽  
Edwin P. Chan ◽  
Qingling Zhang ◽  
Todd Emrick ◽  
...  
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Elastic Modulus ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polymer Thin Films ◽  
Surface Modified ◽  
Surface Modified Nanoparticles

Effect of Low Surface Energy Chain Ends on the Glass Transition Temperature of Polymer Thin Films

2002 ◽  
Vol 35 (5) ◽  
pp. 1491-1492 ◽  
Author(s):  
Fengchao Xie ◽  
H. F. Zhang ◽  
Fuk Kay Lee ◽  
Binyang Du ◽  
Ophelia K. C. Tsui ◽  
...  
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Surface Energy ◽  
Polymer Thin Films ◽  
Low Surface Energy ◽  
Energy Chain

Variations in the glass transition temperature of polyester with special architectures confined in thin films

Polymer ◽  
2010 ◽  
Vol 51 (1) ◽  
pp. 129-135 ◽  
Author(s):  
M. Erber ◽  
A. Khalyavina ◽  
K.-J. Eichhorn ◽  
B.I. Voit
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature

Elastomer Structures and ‘Cold Crystallization’

1979 ◽  
Vol 52 (1) ◽  
pp. 207-212 ◽  
Author(s):  
M. Bruzzone ◽  
E. Sorta
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Melting Point ◽  
Natural Rubber ◽  
Crystallization Rate ◽  
Cold Crystallization ◽  
Structural Defects ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Abstract In a great number of applications an ideal elastomer should satisfy, to a certain extent, both of the following requirements: (1) nearly instantaneous crystallization upon application of strain (strain induced crystallization) and (2) slow or no crystallization when cooled at the temperature of maximum crystallization rate (cold induced crystallization). A noteworthy case of (2) is elastomer crystallization in a strained state. The connection between the points (1) and (2) has not been clearly understood up to now, but it is known that some crystallizable elastomers fulfil the requirements of both (1) and (2) better than others. From an experimental point of view, cold induced crystallization kinetics are substantially easier to measure than those of very fast strain induced crystallization. The phenomenon of cold induced crystallization in natural rubber, NR, has been known since the very beginning of elastomer technology and the tendency of natural rubber to crystallize by cooling has been overcome by crosslinking it with sulphur (vulcanization) without impairing its ability to crystallize by stretching (Goodyear, 1836). The synthesis of cis-polyisoprenes (IR) and cis-polybutadiene (BR) of different microstructural purity (different cis content) gave the possibility of changing the crystallization rate. It has also been reported that the very fast cold crystallization of trans-polypentenamer (TPA) could be reduced by lowering the trans content. The same fact had been observed earlier for trans-polychloroprene. There is a general agreement in postulating that the reduction of the crystallization rate, obtained either by cross-linking or by chain regularity reduction, can be linked with the lowering of the melting point. In both cases the low level of structural defects introduced in the chains does not affect the glass transition temperature in such a way as to vary the crystallization rate. The aim of this paper is to emphasize the importance of the variations of the glass transition temperature and melting point on the elastomeric cold crystallization rate and the way these may be used in planning new elastomer structures.

Study on the Crystallization Activation Energy of Poly (L-lactic acid) Nucleated with P-tert-butylcalix[8]arene

2018 ◽  
Vol 26 (2) ◽  
pp. 169-175
Author(s):  
Yaoqi Shi ◽  
Liang Wen ◽  
Zhong Xin
Keyword(s):  
Activation Energy ◽  
Lactic Acid ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Crystallization Temperature ◽  
Nucleating Agent ◽  
Crystallization Activation Energy ◽  
Temperature Range ◽  
Chain Mobility

The crystallization activation energy (Δ E) of a polymer comprises the nucleation activation energy Δ F and the transport activation energy Δ E*. In this paper, the Δ E of poly (L-lactic acid) (PLLA) nucleated with nucleating agent p- tert-butylcalix[8]arene (tBC8) was calculated. The results showed that the Δ E of nucleated PLLA was 165.97 kJ/mol, which is higher than that of pure PLLA. The reason why Δ E of PLLA increased when incorporating nucleating agent was studied. The increment of glass transition temperature ( Tg) for nucleated PLLA revealed that the polymer chain mobility was restricted by tBC8, which was considered as the reason for the increase of Δ E*. Further, polyethylene glycol (PEG) was added to improve the chain mobility, thus eliminated the variation of the transport activation energy Δ E* caused by tBC8. Then the effect of the increment of crystallization temperature range on the increase of Δ F was also taken into consideration. It was concluded that both decreasing the mobility of chain segments and increasing the crystallization temperature range caused an increase of Δ E for PLLA/tBC8.

scholarly journals Influence of grafting on the glass transition temperature of PS thin films

2017 ◽  
Vol 40 (1) ◽  
Author(s):  
Marceau Hénot ◽  
Alexis Chennevière ◽  
Eric Drockenmuller ◽  
Kenneth Shull ◽  
Liliane Léger ◽  
...  
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature
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