Thermal Stability and Degradation

Xia et al. found that the incorporation of MWNTs and SWNTs did not improve the first degradation temperature, but did improve the second degradation temperature (21). This indicates that carbon nanotubes may preferably interact with the soft segment in polyurethane structure. There were no significant differences between 

SWNTs and MWNTs series. At 1 wt% of SWNT or MWNT loading, the second degradation temperature was delayed by 5°C. 

Generally, the thermal stability of the composites was improved by the addition of the CNTs, which may be attributed to the following combined effects (1) the uniformly dispersed carbon nanotubes presumably provided thermo-oxidative stability to the polymers in the vicinity of the tube surfaces (2) the enhanced thermal conductivity of the composite can facilitate heat transport and thus increase its thermal stability (81) (3) it is possible that the formation of compact chars of CNTs and polymer matrix during the thermal degradation is beneficial to the improvement of thermal stability of the composites (82). 

Moreover, Mondal et al. observed that MWNT could act as a thermal conductor as well as a filler. The thermal stability declined at low MWNT loading (0.25 and 0.50 wt%) (83). This may be due to the increase in the thermal conductivity property of PU by the incorporation of MWNTs which helps the flow of heat to the internal structure of TPU and breaks the bonds of TPU structure. And a further increase of MWNTs improves the thermal stability of TPU due to the filling effect of MWNTs into the TPU matrix. 

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R. D. Shupe and T. D. Baugh. Thermal stability and degradation mechanism of alkylbenzene sulfonates in alkaline media. J Colloid Interface Sci, 145(l) 235-254, August 1991. 

Functional properties and stability of rubbery materials Chapters 1, 3, 4, 7, 12 and 13, give examples of applications of spectroscopic techniques for the characterisation of thermal stability and degradation, kinetics of thermal decomposition, ageing, oxidation and weathering, self-diffusion of small molecules in rubbery materials, adhesion of rubbers to metals, fluid adsorption and swelling. 

In addition, PCTFE has exceptional barrier properties and superb chemical resistance. It is attacked by a number of organic solvents. It has low thermal stability and degrades upon reaching its melting point, requiring special care during processing. 

EGA techniques have been widely used in polymer thermal stability and degradation studies, the analysis of trace impurities and additives, and in the elucidation of polymer structures (12). They are also used in vapor-pressure measurements and toxicity studies of constituents in polymer systems. Langer (128) has reviewed the applications of EGA techniques to polymers as well as numerous other compounds. Only a few illustrative examples will be discussed here. 

The thermal stability and degradation rate of PLA and the formation rate, total yield and enantiomeric fractions of LA depend on a variety of factors (i) the molecular structure, (ii) the type and concentration of initiator, co-initiator, catalyst, and additive, (iii) the concentration of LA and water in PLA, and (iv) the method and reaction conditions including the pressure of the surrounding gas, temperature, and time [157, 273-278]. 

An exhaustive survey of the thermal stabilities and degradation processes of the multitude of polymer families is beyond the scope of this work. Instead, the polymers selected for discussion below are both familiar and representative of the wide range of thermal-oxidative behavior exhibited by polymers [1-13]. 

THE THERMAL STABILITY AND DEGRADATION BEHAVIOR OF THERMOTROPIC LIQUID CRYSTALLINE POLYMERS (TLCPs)... 

G. ElUs, C. Marco, J. del Pino, and M. A. Gomez, Thermal stability and degradation mechanism for two main-chain liquid crystal polyesters A TG-MS study. Journal of Thermal Analysis, 52, 683 (1998). 

Thermal stability and degradation characteristics of the fibre was investigated by TGA/DTG, DTA, and DSC which indicate that thermal stability of the fibres was increased upon treatment with alkali and silane. Fibres are stable up to 300°C without any considerable weight loss. 

Recent Studies on the Thermal Stability and Degradation of Thermosetting Blends... 

Narteh, A.T., Hosur, M., Triggs, E., Jeelani, S. Thermal stability and degradation of diglycidyl ether of bisphenol A epoxy modified with different nanoclays exposed to UV radiation. Polym. Degrad. Stab. 98, 759-770 (2013)... 

Huang N, Chen Z, Liu H, Wang J (2012) Thermal stability and degradation kinetics of poly (methyl methacrylate)/sepiolite nanocomposites by direct melt compoimding. J Macromol Sci Part B 52 521-529... 

Rudnik E., Matuschek G., Milanov N., Kettrup A. Thermal stability and degradation of starch derivatives, J. Thermal. Anal. Cal. 85 (2006) 267. 

Prior to discussing the mechanism of thermal degradation of a hybrid system composed of a mineral deposit and an organic modifier, it is advisable to consider the thermal stability and degradation mechanism of neat components. 

The question of how to spin a lyotropic liquid crystalline polymer which has high thermal stability and degrades before it melts presented a major challenge. Fortunately for the makers of PBO this question had already been answered during the development of Kevlar. PBO is spun directly from the PPA solution used... 

Thermal stability and degradation of the polymers 3(a-d) were analyzed based on the thermograms obtained from TGA at constant heating rate of 20 °C min in the temperature range of 30-800 °C under nitrogen atmosphere. 

In conclusion, as we review our usual collection of data sheets, we should question the quality and relevance of these published data. With an e towards learning more about how a polymer can be processed (melting temperature, Tm, viscosity v. shear rate, shrinkage characteristics, thermal conductivity, as well as thermal stability and degradation and the ability to be recycled, etc.), we must question the sadvantage of not having these data. 

Thermal Stability and Degradation Behavior of Silicone Elastomers... 

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