DSC melting curve

Figure 19 (a) DSC melting curve at atmospheric pressure for PE crystallized at 234°C and 513 MPa for 235 h (b) matching GPC curve after degraded with fuming nitric acid for 10 h. (From Ref. 136.)... 

Figure 21 DSC melting curves at atmospheric pressure for PE-ethyl cellulose mixture crystallized at elevated pressure. (a) 100 MPa (b) 150 MPa (c) 300 MPa (d) 400 MPa and (e) 750 MPa. (From Ref. 117.)...

A result different from that of Nakafuku et al. [144-147] was obtained by us from the study of a binary mixture of PE-ethyl cellulose liquid crystal under high pressure. We have reported [104,117] that addition of 1% ethyl cellulose by weight facilitates the formation of ECC of PE and moderates the conditions for the formation of ECC, that is, the pressure limit is lowered from 440 MPa to 150-200 MPa, and the temperature limit lowered from 200-245°C to 170°C. The DSC melting curves at atmospheric pressure for pure PE (Mt, = 1.06 x 10, p = 0.9556 g/cm ) and PE-ethyl cellulose mixture crystallized at various pressures are shown in Figs. 20 and... 

The heat of fusion AHf (obtained from the area under the DSC melting curve) and percentage crystallinity calculated from AHf is found to be linearly dependent on butadiene content, and independent of the polymer architecture. This is shown in Figure 3. Also, the density of the block copolymers was found to be linearly dependent on butadiene content (see Figure 4). The linear additivity of density (specific volume) has been observed by other workers for incompatible block copolymers of styrene and butadiene indicating that very little change in density from that of pure components has occurred on forming the block copolymers.(32) While the above statement is somewhat plausible, these workers have utilized the small positive deviation from the linear additivity law to estimate the thickness of the boundary in SB block copolymers.(32)... 

The polymers mostly used in pharmaceutical packaging are polyethylene, polypropylene, PVC, polyamide, polystyrol, nylon, cellulose acetate, polyethylene terephthtalate, and blends thereof. Copolymers and rubbers are also used. The DSC melting curve of polyethylene used for packaging purposes is characteristic. Low- and high-density polyethylene are differentiated by their melting points. " Melting point and density of polyethylene are linearily correlated. " Crystallinity may be determined as described above for amorphous state. 

Brown (60) also discussed the DSC melting curve. The output of the DSC is proportional to the heat capacity of the system, dH/dT, or... 

Since dHjdt is proportional to dH/dT, plots of dH/dT against T represent the initial part of the idealized DSC melting curve. 

The real DSC melting curve, because of factors such as thermal lag, looks more like the inset in Figure. 10.15. The range of F values used in practice is usually restricted to 0.1 < F < 0.4. Even in this restricted range, the linearity of plots of T against 1/F is often poor. Corrections must be made for thermal lag (49) and undetected premelting. 

Figure 3.5 DSC melting curves for HDPE, LDPE, and their 1 1 blend.

DSC melting curves associated with aromatic nylons have been reported for various compositions of the two components. 

Figure 6. DSC melting curves of Z-N catalyzed LLDPE/VLDPE and metallocene catalyzed resins. (Reproduced with permission from reference 25. Copyright 2002 Taylor and Francis Group, LLC.)...

Figure 10. DSC melting curves and melting point versus density of OBCs and POE random copolymers.

DSC melting curves of (I) polyethylene extended chain-type crystals prepared by crystallization at 470 K under 500 MPa pressure and (II) folded chain-type polyethylene crystals prepared under atmospheric pressure... 

DSC melting curves of polyethylene film stretched 20 times. (I) First heating and (II) second heating scans... 

Fig. 7.3. Typical DSC melting curve of polyethylene samples (EH064 and EB059) rapidly crystallized from melt. Heating rate 10 C/min...

DSC is another tool giving access to the lamellar thickness distribution. Based on the form of the DSC melting curve, the average distribution of the lamellae thickness may be determined. This procedure is based on the assumption that the melting temperature is related to the thickness L of a crystalline lamella, by the Thomson-Gibbs relationship [8] ... 

Figure IV - 19, Schematic drawing showing how to obtain a pore size distribution from a DSC melting curve.

Figure 4.23 DSC melting curve of polyethylene (361 heating rate 5 C min, nitrogen atmosphere)...

Figure 4.26 DSC melting curves for (a) LDPE and (b) HDPE. For I-IV. see Table 4-5 Sample Ma.ss, 10 mg heating rate, 10 °C min ...

Figure 4.99 shows the DSC melting curves for the mixed fat. It can be seen that the DSC curve I for pure lard exhibits a strong endothermic peak at about 30 "C, and from curves II-IV for the mixed fat both the peak temperature and area decrease with increase in the proportion of beef fat in the samples. Finally, the peak almost disappears in the case of pure beef fat (curve V). Hence the content of beef fat (or other fat) in mixed fat can be evaluated from the peak heights on the DSC curves [114. ... 

A typical DSC melting curve and a plot of the sample temperature versus the reciprocal area... 

Figure 11. DSC melting curves of HDPE/LDPE blends, = 2.5 K/min.

No glass transition temperature (Tg) between -100 to 100°C was observed for completely hydrogenated cis-1,4 PB. The melting temperature is around 125 to 129°C which is inversely related to the molecular weight (Table 2). The density of H(cis-PB) is in the range of 0.937 to 0.940 and is also inversely affected by the MW. The density is directly related to the crystallinity which was calculated from heat of fusion, AHf, i.e., the area under the DSC melting curve. 

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