Vibrational Spectroscopic and Ultrasound Analysis for In-Process Characterization of High-Density Polyethylene/Polypropylene Blends during Melt Extrusion

Abstract

Spectroscopic techniques such as Raman, mid-infrared (MIR), and near-infrared (NIR) have become indispensable analytical tools for rapid chemical quality control and process monitoring. This paper presents the application of in-line Fourier transform near-infrared (FT-NIR) spectroscopy, Raman spectroscopy, and ultrasound transit time measurements for in-line monitoring of the composition of a series of high-density polyethylene (HDPE)/polypropylene (PP) blends during single-screw extrusion. Melt composition was determined by employing univariate analysis of the ultrasound transit time data and partial least squares (PLS) multivariate analysis of the data from both spectroscopic techniques. Each analytical technique was determined to be highly sensitive to changes in melt composition, allowing accurate prediction of blend content to within ±1% w/w (1σ) during monitoring under fixed extrusion conditions. FT-NIR was determined to be the most sensitive of the three techniques to changes in melt composition. A four-factor PLS model of the NIR blend spectra allowed determination of melt content with a standard prediction error of ±0.30% w/w (1σ). However, the NIR transmission probes employed for analysis were invasive into the melt stream, whereas the single probes adopted for Raman and ultrasound analysis were noninvasive, making these two techniques more versatile. All three measurement techniques were robust to the high temperatures and pressures experienced during melt extrusion, demonstrating each system's suitability for process monitoring and control.

Keywords

Spectroscopy Raman Near-infrared region Polymer blends Extrusion In-line monitoring Process monitoring

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References

Coates

P. D.

Barnes

S. E.

Sibley

M. G.

Brown

E. C.

Scowen

I. J.

and Edwards

H. G. M

, Polymer 44, 5937 (2003).

Billmeyer

F. W.

, Textbook of Polymer Science (Wiley Interscience, New York, 1984), 3rd ed.

Sato

Sasao

Matsukawa

Kita

Yamaguchi

Siesler

H. W.

and Ozaki

, Macromol. Chem. Phys. 204, 1351 (2003).

Pawlak

Pluta

Morawiec

Galeski

and Pracella

, Eur. Polym. J. 36, 1875 (2000).

Bains

Reshadat

Lew

Cluett

W. R.

and Balke

S. T

, SPE ANTEC, Conference Proceedings (Society of Plastics Engineers, CRC Press, Boca Raton, FL, 1994), p. 2227.

Eagles

D. C.

and Rudin

, Plast. Rubber Compos. Process. Appl. 9, 163 (1988).

Chalmers

J. M.

and Everall

, Polymer Characterization, Hunt

B. J.

and James

M. I

, Eds. (Blackie Academic and Professional, Glasgow, 1993).

Meszlenyi

and Kortvelyessy

, Polym. Test. 18, 551 (1999).

Lew

and Balke

S. T

, Appl. Spectrosc. 47, 1747 (1993).

10.

Reshadat

Desa

Joseph

Mehra

Stoev

and Balke

S. T

, Appl. Spectrosc. 53, 1412 (1999).

11.

Reshadat

and Balke

S. T

, Appl. Spectrosc. 53, 1309 (1999).

12.

Rohe

Becker

Kolle

Eisenreich

and Eyerer

, Talanta 50, 283 (1999).

13.

Rohe

, Ph.D. Thesis, University of Stuttgart, Stuttgart, Germany (2001).

14.

Barnes

S. E.

, Ph.D. Thesis, University of Bradford, Bradford, UK (2004).

15.

Hansen

M. G.

and Khettry

, SPE ANTEC Conference Proceedings (Society of Plastics Engineers, CRC Press, Boca Raton, FL, 1995), 2, 2820.

16.

Fischer

and Eichhorn

K. J

, Proceedings of the 15th European Symposium on Polymer Spectroscopy (Wiley-VCH, New York, 2003), p. 86.

17.

Lewis

I. R.

and Griffiths

P. R

, Appl. Spectrosc. 50(10), 12A (1996).

18.

Lipp

E. D.

and Leugers

M. A

, “Raman spectroscopy in chemical process analysis”, in Spectroscopy in Process Analysis, Chalmers

J. M.

Ed. (Sheffield Academic Press, Sheffield, UK, 2000).

19.

Hourston

D. J.

and Hughes

I. D

, Polymer 18, 1175 (1977).

20.

Hourston

D. J.

and Hughes

I. D

, Polymer 19, 1181 (1978).

21.

Singh

Y. P.

and Singh

R. P

, Eur. Polym. J. 19, 529 (1983).

22.

Singh

Y. P.

and Singh

R. P

, Eur. Polym. J. 19, 535 (1983).

23.

Franca

D. R.

Jen

C. K.

Nguyen

K. T.

and Gendron

, Polym. Eng. Sci. 40, 82 (2000).

24.

Piche

, Society of Plastics Engineers Technical Papers 44, 3617 (1998).

25.

Brown

E. C.

Olley

and Coates

P. D

, Plast. Rubber Compos. 29, 3 (2000).

26.

Erwin

and Dohner

, Polym. Eng. Sci. 24, 1277 (1984).

27.

Mikkonen

and Savolainen

A. J

, Appl. Polym. Sci. 39, 1709 (1990).

28.

Gendron

Tatibouët

Guèvremont

Dumoulin

M. M.

and Piché

, Polym. Eng. Sci. 35, 79 (1995).

29.

Verdier

and Piau

, J. Phys. D: Appl. Phys. 29, 1454 (1996).

30.

Barnes

S. E.

Sibley

M. G.

Edwards

H. G. M.

Scowen

I. J.

and Coates

P. D

, SPE ANTEC Conference Proceedings (Society of Plastics Engineers, CRC Press, Boca Raton, FL, 2002), p. 45.

31.

Jen

C. K.

Sun

and Kobayashi

, SPE ANTEC, Conference Proceedings (Society of Plastics Engineers, CRC Press, Boca Raton, FL, 2004), 1, 402.

32.

Davis

K. L.

Tedesco

J. M.

and Shaver

, SPIE-Int. Soc. Opt. Eng. 3608, 148 (1999).

33.

Brown

E. C.

, Ph.D. Thesis, University of Bradford, Bradford, UK (1998).

34.

Coates

P. D.

Brown

E. C.

and Smith

G. D

, “Ultrasonic velocity monitoring of polymer processing” in In-Process Measurements Series, Coates

P. D.

Ed. (University of Bradford, UK, 2004).

35.

Brown

E. C.

Collins

T. L. D.

Dawson

A. J.

Olley

and Coates

P. D

, J. Reinf. Plast. Compos. 18, 331 (1999).

36.

Walmsley

A. D.

, “Chemometrics and data treatment,” in Spectroscopy in Process Analysis, Chalmers

J. M.

Ed. (Sheffield Academic Press, Sheffield, 2000).

37.

Vedula

and Hansen

M. G

, J. Appl. Polym. Sci. 68, 859 (1998).

38.

Apruzzese

Reshadat

and Balke

S. T

, Appl. Spectrosc. 56, 1268 (2002).