Differential scanning calorimetry polymer transition behavior

Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) are also very useful tools for the characterization of polymers. TGA and DSC provide die information about polymer stability upon heating and thermal behaviors of polymers. Most of the polymers syndiesized via transition metal coupling are conjugated polymers. They are relatively stable upon heating and have higher Tgs. 

Differential Scanning Calorimetry. Some structural information is provided by the thermal behavior of the polymer. The homopolymer of DPP crystallizes when heated above the glass transition temperature. A crystallization exotherm at the appropriate temperature therefore indicates the presence of DPP blocks, either as the homopolymer or in a block copolymer. 

Dynamic mechanical property (DMP) measurements are used to evaluate the suitability of a polymer for a particular use in sound and vibration damping. Since the dynamic mechanical properties of a polyurethane are known to be affected by polymer morphology (4), it is important to establish the crystallization and melting behavior as well as the glass transition temperature of each polymer. Differential scanning calorimetry (DSC) was used to determine these properties and the data used to interpret the dynamic mechanical property results. 

Various methods have been employed to find out about the structure of polymer electrolytes. These include thermal methods such as differential scanning calorimetry (DSC), differential thermal analysis (DTA), X-ray methods such as X-ray diffraction and X-ray absorption fine structure (XAFS), solid state NMR methods particularlyusing7LiNMR,andvibrationalspectroscopicmethodssuch as infrared and Raman [27]. The objective of these various studies is to establish the structural identity of the polymer electrolyte at the macroscopic as well as the molecular levels. Thus the points of interest are the crystallinity or the amorphous nature of materials, the glass transition temperatures, the nature and extent of interaction between the added metal ion and the polymer, the formation of ion pairs etc. Ultimately the objective is to understand how the structure (macroscopic and molecular) of the polymer electrolyte is related to its behavior particularly in terms of ionic conductivity. Most of the studies have been carried out, quite understandably, on PEO-metal salt complexes. In comparison, there has been no attention on the structural aspects of the other polymers particularly at the molecular level. 

The glass transition temperature (Tg) of cellulose reinforced composites is an important parameter which influences different properties of the resulting composite such as mechanical behavior, matrix chains dynamics and swelling behavior. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) are used to evaluate the Tg value of cellulose nanocomposites. In some cases, the addition of cellulose nanocrystals into polymer matrices does not seem to affect the... 

Figure 6 (a) Correlation between the turbidimetric profile as a function of temperature and differential scanning calorimetry (DSC) thermogram for a chemically synthesized polymer of (Val-Pro-Gly-Val-Gly) in water, (b) Photographic illustration of the phase behavior of poly(Val-Pro-Gly-Val-Gly) in aqueous solution at temperatures below (5 °C) and above (40 °C) the inverse temperature transition, 7,. Reprinted from Arias, F. J. Reboto, V. Martin, S. etal. Blotechnol. Lett. 2006,25(10), 687. Copyright 2006, with permission from Springer. 

The preparation of ZnO/ PS nanocomposites preceded as follows [112] First, 110 mg bare ZnO or 110 mg PMMA-grafted ZnO were added into a three-necked bottle. Then, 10 mL styrene was added into the reactor. The mixture was stirred with the aid of ultrasonic oscillation until a uniform dispersion of the ZnO particles in styrene was attained. Afterwards, 36 mg azobisisobutyronitrile (AIBN) was added into the reactor as initiator. The subsequent polymerization was conducted at 85°C for 2.5 h. Then, the obtained composites were dried under vacuum for 24 h. The differential scanning calorimetry (DSC) heating curves of neat PS, PS/ZnO (bare), and PS/ZnO (PMMA grafted) are shown in Fig. 10. DSC traces in Fig. 10a show that neat PS has a lower glass transition temperature (Tg = 87.7°C) than PS/ZnO (bare, 7 g = 97.9°C) and PS/ZnO (PMMA grafted, Tg = 95.3°C). This behavior can be explained by the restricting effect of the nanoparticles in polymer. ZnO... 

Differential scanning calorimetry (DSC) is a thermoanalytical technique used to study the thermal properties of the polymer using a differential scanning calorimeter. In this process, the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a function of temperature. Sample and reference will be maintained at same temperature throughout the experiment. DSC curves were plotted based on heat flux versus temperature or time. Thermal transitions of polymer can be determined by this technique. DSC is widely used for the decomposition behavior determination of the polymer. Figure 17.8 shows the DSC curves of PHB. 

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