Viscosity of polyamides
Ted Brink
Page  2
Effects of molecular weight
The molecular weight of a polymer influences:
• melt viscosity (flow behaviour)
• pro...
Page  3
Methods to measure molecular weight
• Melt viscosity as a function of shear rate
• MFI (Melt Flow Index)
• MVR (M...
Page  4
MFI and MVR
Disadvantages
for polyamide
characterization:
• moisture sensitivity
• polymer reactivity
Units:
• MF...
Page  5
Limitations of MFI measurement
100100010000
0.01 0.1 1 10 100 1000
γ
η
Two types of materials
with the same MFI v...
Page  6
RSV and VN according to ISO 307
• solvents used:
- 90 % formic acid
- 96 % sulphuric acid
- 100 % m-cresol
- othe...
Page  7
GPC/SEC
0
5
10
15
20
25
15 20 25 30 35
Ve (ml)
RawRIsignal(mV)
0
0.2
0.4
0.6
0.8
1
1.2
3 3.5 4 4.5 5 5.5 6
LogM
d...
Page  8
Methods to express molecular weight
η0 at
260 °C
MFI at
250 °C
Mn Mw VN
RSV
H2SO4
RSV
HCOOH
Pa.s g/10 ‘ g/mol g/m...
Page  9
Relation MFI and RSV (in formic acid)
0
10
20
30
2 2.5 3 3.5 4
Meltflowindex[g/10min]
Relative solution viscosity...
Page  10
Contact
Ted Brink
tel.: +31 (0) 651109899
email: ted.brink@extrusionist.com
internet: www.extrusionist.com
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Polyamide viscosity measurement methods

Different ways to express the molecular weight of polyamides
Published on: Mar 4, 2016
Published in: Technology      Business      
Source: www.slideshare.net


Transcripts - Polyamide viscosity measurement methods

  • 1. Viscosity of polyamides Ted Brink
  • 2. Page  2 Effects of molecular weight The molecular weight of a polymer influences: • melt viscosity (flow behaviour) • processing behaviour • mechanical properties • crystallization behaviour • optical properties
  • 3. Page  3 Methods to measure molecular weight • Melt viscosity as a function of shear rate • MFI (Melt Flow Index) • MVR (Melt Volume Rate) • RSV (Relative Solution Viscosity) • VN (Viscosity Number) • GPC (Gel Permeation Chromatography) • SEC (Size Exclusion Chromatography)
  • 4. Page  4 MFI and MVR Disadvantages for polyamide characterization: • moisture sensitivity • polymer reactivity Units: • MFI in g/10 min • MVR in cm3/10 min Capillary ( D = 2.0955 mm, L = 8.000 mm ) Barrel ( D = 9.5504 mm ) Piston ( D = 9.4742 mm ) Temperature Control ( ± 0.2oC ) Thermometer or PRT ( ± 0.1oC ) Load (Wt + Piston = ± 0.5% )  Standardized test (ASTM D1238, ISO 1133)  Constant load test  Fixed die diameter  Fixed die L/D ratio  Mass / time measured  MFR  1/Viscosity  May be related to, but is not a strict function of Mw
  • 5. Page  5 Limitations of MFI measurement 100100010000 0.01 0.1 1 10 100 1000 γ η Two types of materials with the same MFI value but completely different rheological behavior Hygroscopic and chemical character of PA6 influence accuracy of measurement melt index conditions A B
  • 6. Page  6 RSV and VN according to ISO 307 • solvents used: - 90 % formic acid - 96 % sulphuric acid - 100 % m-cresol - others • concentration 1 g polymer/100 ml • measured at 25 °C • Ubbelohde capillary RSV = Tsolution/Tsolvent VN = (Tsolution/Tsolvent)/c
  • 7. Page  7 GPC/SEC 0 5 10 15 20 25 15 20 25 30 35 Ve (ml) RawRIsignal(mV) 0 0.2 0.4 0.6 0.8 1 1.2 3 3.5 4 4.5 5 5.5 6 LogM dw/dLogM
  • 8. Page  8 Methods to express molecular weight η0 at 260 °C MFI at 250 °C Mn Mw VN RSV H2SO4 RSV HCOOH Pa.s g/10 ‘ g/mol g/mol cm3/g 1070 7.7 18000 35000 197 3.3 3.0 1280 7.1 20000 40000 210 3.6 3.2 2600 3.3 22000 47000 245 4.0 3.6
  • 9. Page  9 Relation MFI and RSV (in formic acid) 0 10 20 30 2 2.5 3 3.5 4 Meltflowindex[g/10min] Relative solution viscosity in formic acid MFI measured at 235 °C and 2.16 kg
  • 10. Page  10 Contact Ted Brink tel.: +31 (0) 651109899 email: ted.brink@extrusionist.com internet: www.extrusionist.com

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