Unterschiede
Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
| Beide Seiten der vorigen RevisionVorhergehende ÜberarbeitungNächste Überarbeitung | Vorhergehende Überarbeitung | ||
| en:materialdaten:molekulargewicht [2024/10/17 17:23] – [Molecular weight] neelest | en:materialdaten:molekulargewicht [2025/05/20 11:22] (aktuell) – cschall | ||
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| ======Molecular weight====== | ======Molecular weight====== | ||
| - | ToDo: Dialoge | + | ===== Material data - Molecular weight ===== |
| - | Eingabemaske zu Materialabbauparametern und MFI ergänzen | + | The material data on molecular weight are optional entries. |
| - | Eingabewerte 5 Materialparameter erklären. | + | The MFI and MVI (with given test temperature and weight) are only used to complete the material data for information purposes and are not required for any calculation. |
| - | Beispielwerte nennen | + | The parameters for the material degradation calculation can be activated as required. \\ |
| + | If the checkbox is activated, the 5 material parameters $K_T$, $n_T$, $K_\dot{\gamma}$, | ||
| - | Wird der ganze Inhalt da unten wirklich benötigt? | + | {{ : |
| + | ===== Exemplary values ===== | ||
| - | FIXME | + | ^ Plastic type^ MFR (g/10 min) ^ $K_T [°C] $ ^ $n_T [-] $ ^ $K_\dot{\gamma} [1/s] $ ^ $n_\dot{\gamma} [-]$ ^$\eta_\infty^* [-]$ ^ |
| + | | PP | 3,0 | 345,7 | 15,29 | 1171,4 | 1,47 | 0,415 | | ||
| + | | PP | 3,0 | 355,3 | 13,75 | 882,3 | 1,62 | 0,417 | | ||
| + | | PP | 47,0 |1617,0| 3,15 | 6989,3 | 0,85 | 0,531 | | ||
| + | | PP | 8,0 | 344,8 | 15,41 | 1861,1 | 1,15 | 0,386 | | ||
| + | | PS | 1,5 | ||
| + | | PS | 12,0 | 761,5 | 40,36 | 8740,6 | 0,63 | 0,361 | | ||
| - | ===== Molecular weight ===== | ||
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| - | The molecular mass distribution can be characterised by the following quantities. | ||
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| - | The **numerical average $M_n$** is given by the following equation: | ||
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| - | \[M_n = \frac{\sum N_i \cdot M_i}{\sum N_i}\] | ||
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| - | $N_i$ is the number of molecules of group $i$ and $M_i$ is the molar mass of the respective | ||
| - | group. | ||
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| - | The **weight average $M_w$** is defined by: | ||
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| - | \[M_w = \frac{\sum N_i \cdot {M_i} ^2}{\sum N_i \cdot M_i}\] | ||
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| - | The **polydispersity (PD)** is a measure of the width of molecular weight distribution and | ||
| - | it´s the quotient of weight average and number avergage. | ||
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| - | \[PD = \frac {M_w}{M_n}\] | ||
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| - | The polydipersity is always PD ≥ 1. The higher the PD value, the broader the distribution. | ||
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| - | The measurement of the **solvent viscosity** or **intrinsic viscosity** | ||
| - | indirectly indicates a change in the molecular mass, as the flow time of a damaged polymer is | ||
| - | of a damaged polymer compared to the raw material. The | ||
| - | intrinsic viscosity is linked to the molecular mass via the Mark-Houwink relationship: | ||
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| - | \[[η] = K \cdot \bar{M^a}\] | ||
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| - | $[η]$ = Staudinger index | ||
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| - | $K, a$ = empirically determined constants | ||
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| - | $ \bar{M}$ = weight average or viscosity average of the molecular mass | ||
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| - | The determination of $[η]$ instead of extrapolating to the concentration c = 0 $\frac{g}{l}$ by measuring the intrinsic viscosity at only one concentration using an estimate. The estimation according to Schulze-Blaschke is carried out by a prior calibration of the $K_{SB}$ coefficient, | ||
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| - | The **viscosity number (VZ)** [$\frac{cm^3}{g}$] is characterised by: | ||
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| - | $$ VZ = (\frac {η}{η_s} - 1) \cdot \frac {1}{c} $$ | ||
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| - | $η$ = dynamic viscosity of the solution | ||
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| - | $η_s$ = dynamic viscosity of pure solvent | ||
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| - | $c$ = concentration in $\frac{g}{cm^3}$ | ||
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| - | The Billmeyers **intrinsic viscosity** [$\frac{dl}{g}$] is calculated by: | ||
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| - | $$ IV = 0,25 \cdot VZ + \frac{3\cdot ln(\frac{t}{t_s})} {4\cdot c} $$ | ||
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| - | $t$ = flow time of the solution | ||
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| - | $t_s$ = flow time of the pure solvent | ||
| ===Further topics=== | ===Further topics=== | ||
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