Degree crystallinity

The melting process normally occurs imder isobaric conditions where the heat of fusion is equal to the melting enthalpy. For PLA, PCL and PHB the value the heat of fusion of a 100% crystalline polymer is 93 J/g, 139 J/g and 146 J/g, respectively [48]. 

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The thermally expanded graphite was used without any preliminary treatment the carbon was synthesized by carbonation of the raw material in an argon flow at 500°C with subsequent thermal treatment. Carbon residues strongly differing in the crystallinity degree were obtained as depends on the temperature which ranged from 500°C to 1300°C. The identity of each material was checked by X-ray spectroscopy. 

Figure 25 Master strcss-rejaxation curves of bisphenol A polycarbonate of different degrees of Crystallinity. Degrees of Gystallinity are shown by curves. Reference temperature is I55°C. (From Ref. 217.)...

Figure 3. Plot of linewidth, against temperature at 67.9 MHz for two linear PE samples having a spherulitic morphology but differing levels of crystallinity degree of cryHallinity 0.78, (O) degree of crystallinity 0.50, (9).

The powder XRD-pattems of a typical ZSM-5 formation series are shown in figure 3. Again, the pattern labeled tk = 0 h is due to the starting porous glass. At a crystallization time of 46 h the typical MFI reflections are just detectable on top of the broad amorphous background. The crystallinity degree was at this crystallization stage QAi=0.03, which... 

One of the golden rules for a successful work in HT experiments is the automation of the entire workflow, i.e. one must be able to produce what one is able to analyze, because a variety of solid phases and distinct structural features can be obtained across a typical 6x8 matrix. Therefore, the characterization of structural properties of catalytic materials, as for example crystallinity degree, requires the application of X-ray microdiffractometers [50] fitted with GADDS (Brucker). The collimated beams of about 500 p diameter... 

Polymer class General properties Range of use temperatures Degree of crystallinity Degree of cross linking Example... 

The gasphase HDPE of industrial production mark 276 with average weight molecular weight Mw 1,5 x 105 and crystallinity degree 0,68, determined by samples density, is used. 

PMCS-4 with different ratios of trans- and cis-sequences in the backbone possess one and the same glass transition temperature, and the crystallinity degree is lower that for PDMS. While polymeric chain is enriched by trans-units, crystallinity increases [27], By methods of DSC, X-ray diffraction and thermooptical analysis, it have been detected that besides glass transition (Tg) and melting (Tmeit), polymers synthesized from monomers containing up to 95 - 100% of tram-isomers display a phase transition in the temperature range of 70 - 90°C, which is simulated as a transition from meso-morphous to isotropic state (Figure 2). 

Thus considered data on three POCS-4 possessing different spatial structures do not allow an un-ambiguous conclusion that enrichment of the polymer by //-sequence units always causes occurren- ce of a mesophase, but hence, in the majority of cases the crystallinity degree is increased. Apparently, the data obtained should indicate that higher contribution to stabilization of the mesophases is provided by strong intermolecular... 

Differential scanning calorimetry (DSC) The method to measure the heat flow to a sample as a function of temperature. It is used to measure, for example, specific heats, glass transition temperatures, melting points, melting profiles, degree of crystallinity, degree of cure, and purity. 

When the TTS principle is carried out, the non-isothermic crystallization kinetics can be described by replacing argument t in the dependence of non-crystallinity degree of time during isothermic crystallization. The replacement equation is... 

The deactivation and coke formation over ferrierite was recently related to the crystallinity degree of the zeolite (9). 

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