If you are talking about polymers, usually a literature reference is used for 100% crystalline material's melting heat and the actually measured melting heat is divided by this reference value. This is not an absolute method. The 100% crystalline value is obtained by extrapolation using values on samples of various crystallinity.  It is usually calibrated by X--ray (integration of the crystalline peaks and the amorphous halo) or by density measurement (although the  latter  is also not absolute, should be calibrated  by X-ray). DSC melting curves contain a  lot of information, e.g. about lamella-distribtuion, recrystallization etc.  Usually two, repeated DSC masurements are made to erase the crystallization history during sample preparation. It also contains the crysttallization heat .

The degree of crystallinity (of partial crystalline materials) is defined as the quotient of the enthalpy difference between pure amorphous phase and the sample enthalpy over the difference of pure amorphous and pure crystalline material;

wc = (hamorph-hsample) / (hamorph-hcryst)

All quantities are temperature dependent. The respective functions may be got from literature, or determined from cp-measurements: h(T)= Integral(cp).

a detailed example is published in the book: Sarge, Höhne, Hemminder:"Calorimetry" published by WILEY-VCH in 2014 on pages247 - 256

The simple integration of the melting peak area and division by the melting enthalpy of the respective substance is not precise enough, because the degree of crystallinity is a function of temperature and changes with increasing temperature during the run.

Regards Gunther Höhne

DSC test: Xc= crystallinity of delta H/ Delta Ho

Melting heat Delta H: testing sample

The heat of melting Ho: 100% crystalline specimens (can be found)

XRD is the area of Ac/ (Ac+KAa) in the crystalline region.

Area of Ac: crystal

Area of Aa:

K: correction factor

The crystallinity of DSC and XRD may be different.

Thank you so much all of you.

by taking Area under melting peak and and of pure PEO (ref. value in J/g) or your host polymer...

Thank u, Sir

Prof. Günther W. H. Höhne

Regarding your statement, " The respective functions may be got from literature, or determined from cp-measurements: h(T)= Integral(cp)", is it also the same if we extract h(T) from the heat flow versus time curve? As we are interested in J/g.

In DSC's we measure always heat flow rates against time. To determine the heat capacity of asample from the measured heat flow rate needs some efforts. (see our book "Differential scanning calorimetry" for details)., only some DSC allow precise cp-measurements. Integrating the peak in a heat flow function results in a heat of transition or reaction, this is equal to the enthalpy of transition in the case of constant pressure. This is normally the case in DSC-measurements, so heat of transition and enthalpy of transition or reaction are equal (both have the same unit J/g or J/mol). The attached paper may help you to understand the thermodynamic backgraund. God luck.

Here is an easy calculator for the same,

https://www.instanano.com/2019/05/Percent-Crystallinity-Calculator-form-Differential-Scanning-Calorimetry-DSC.html

plot your graph in mW vs time or mW/g vs time. (where mW=mJ/s or mW/g= J/g*s)

Integrate the area of the melting peak. that will give you J*min/g*s. Finally, convert the min to sec to obtain J/g or heat of fusion of dHm or dHf.

%crystallinitty=(dHm experimental (calculated data) /dHm of 100% crystalline polymer) *100

Thank you all of you

from the heat fusion of the material

how to increase the degree of crystallinity in DSC?

Here is an easy formula for the same,

Find this article for details

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