Transition temperature peak

Contemporaneously with Vohra, Michler and co-workers [32] carried out a detailed study of microwave-assisted CVD diamond film growth in methane/carbon dioxide gas mixtures on silicon wafers at different substrate temperatures (560-275°C) by XRD, transmission electron microscopy (TEM), AFM, and Raman spectroscopy. At temperatures above 430°C, the films consisted of nearly defect-free near-(112)-oriented grains with smooth (111) facets, exhibiting steps and risers at the surface. Below a transition region of 340-385°C, the film quality was much deteriorated, as evidenced by much smaller crystal size, increased twin density, and amorphous inclusions at incoherent twin boundaries. The Raman spectra (514.5-nm excitation) in the high-temperature region contained no peaks, but above the transition temperature, peaks at around 1430 and 1540 cm were evident, which the authors attributed to amorphous inclusions (Fig. 9). These observations are consistent with those of Vohra et al. [31] just mentioned. 

Tackifying resins enhance the adhesion of non-polar elastomers by improving wettability, increasing polarity and altering the viscoelastic properties. Dahlquist [31 ] established the first evidence of the modification of the viscoelastic properties of an elastomer by adding resins, and demonstrated that the performance of pressure-sensitive adhesives was related to the creep compliance. Later, Aubrey and Sherriff [32] demonstrated that a relationship between peel strength and viscoelasticity in natural rubber-low molecular resins blends existed. Class and Chu [33] used the dynamic mechanical measurements to demonstrate that compatible resins with an elastomer produced a decrease in the elastic modulus at room temperature and an increase in the tan <5 peak (which indicated the glass transition temperature of the resin-elastomer blend). Resins which are incompatible with an elastomer caused an increase in the elastic modulus at room temperature and showed two distinct maxima in the tan <5 curve. 

Particular phospholipids display characteristic transition temperatures (Tm). As shown in Table 9.1, increases with chain length, decreases with unsaturation, and depends on the nature of the polar head group. For pure phospholipid bilayers, the transition occurs over a narrow temperature range. The phase transition for dimyristoyl lecithin has a peak width of about 0.2°C. 

Glass transition temperature (Tg) for pure NR is —63.43°C, while for the nanocomposite it increases to —61.92°C. NR-rectorite nanocomposite shows a higher glass transition temperature, lower tan 8 peak, and slightly broader glass transition region compared to pure NR. 

The DSC spectra confirm that the fluid phase of the polymerized vesicles remains and the phase transitions are retained with the introduction of the spacer group. As can been seen in Figure 8 of the DSC spectrum of the monomeric lipid, there is a peak around 28°C which corresponds to the phase transition of monomeric lipid. As the result of the presence of the spacer group, a similar phase transition can also be observed clearly in the spectrum of the polymerized lipid as shown in Figure 9, but the transition temperature is increased to 36°C by the presence of the polymer chains. 

Two transition regions are apparent in the tan 6 plot the low temperature Y peak around -120°C and a higher temperature peak centered around +20°C (note that the higher tetnperature value for this peak as compared to that of HB,PQ in Figure 14B is due to two factors 1. Longer room temperature annealing for the sample... 

---