Computer Applications in Applied Polymer Science

454 Pages·1982·6.548 MB·English

by  Theodore Provder (Eds.)

Computer Applications in
Applied Polymer Science
In Computer Applications in Applied Polymer Science; Provder, T.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
In Computer Applications in Applied Polymer Science; Provder, T.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
Computer Applications in
Applied Polymer Science
Theodore Provder, EDITOR
Glidden Coatings and Resins
Based on a symposium
sponsored by the Division
of Organic Coatings and
Plastics Chemistry
at the 182nd Meeting of
the American Chemical Society,
New York, New York,
August 23-28, 1981.
ACS SYMPOSIUM SERIES 197
AMERICAN CHEMICAL SOCIETY
WASHINGTON, D. C. 1982
In Computer Applications in Applied Polymer Science; Provder, T.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
Library of Congress Cataloging in Publication Data
Computer applications in applied polymer science.
(ACS symposium series, ISS
Includes bibliographies an
1. Plastics—Data processing—Congresses. 2. Coat
ings—Data processing—Congresses.
I. Provder, Theodore, 1939- . II. American
Chemical Society. III. American Chemical Society.
Division of Organic Coatings and Plastics Chemistry.
IV. Series.
TP1122.C65 1982 667'.9 82-13735
ISBN 0-8412-0733-X ACS MC8 197 1-448 1982
Copyright © 1982
American Chemical Society
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PRINTED IN THE UNITED STATES OF AMERICA
In Computer Applications in Applied Polymer Science; Provder, T.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
ACS Symposium Series
M. Joan Comstock, Series Editor
Advisory Board
David L. Allara Marvin Margoshes
Robert Baker Robert Ory
Donald D. Dollberg Leon Petrakis
Robert E. Feeney Theodore Provder
Brian M. Harney Charles N. Satterfield
W. Jeffrey Howe Dennis Schuetzle
James D. Idol, Jr. Davis L. Temple, Jr.
Herbert D. Kaesz Gunter Zweig
In Computer Applications in Applied Polymer Science; Provder, T.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
FOREWORD
The ACS SYMPOSIUM SERIES was founded in 1974 to provide
a medium for publishing symposia quickly in book form. The
format of the SERIES parallels that of the continuing ADVANCES
IN CHEMISTRY SERIES except that in order to save time the
papers are not typeset but are reproduced as they are sub
mitted by the authors in camera-ready form. As a further
means of saving time, the papers are not edited or reviewed
except by the symposium chairman, who becomes editor of
the book. Papers published in the ACS SYMPOSIUM SERIES
are original contributions not published elsewhere in whole or
major part and include reports of research as well as reviews
since symposia may embrace both types of presentation.
In Computer Applications in Applied Polymer Science; Provder, T.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
PREFACE
THE USE OF COMPUTERS in applied polymer science and technology has
been growing at an exponential rate over the last several years. This has
been brought about by the continued improvement in cost/performance
in medium size and minicomputer systems. The microcomputer explosion
over the last five years has significantly accelerated the use of computers
in the laboratory by providing the average chemist hands-on moderate
computer power at low cost. The microcomputer, more readily, has
enabled the polymer scientist and technologist to perform complex calcu
lation, to automate instrumentation for monitoring, data analysis and
instrument control, and
physical and chemical processes.
The topics in this book reflect the growth in the application of com
puter science and technology to the broad field of polymer science. The
book is divided into three main sections. The first section deals with
polymerization process modeling and control. The papers in this section
cover a variety of polymerization processes, bulk polymerization, solution
polymerization, emulsion polymerization, and condensation polymeriza
tion including homo- and co-polymerization. The second section covers
the field of instrumentation automation for polymer characterization and
modeling. The instruments covered in this section include viscometer,
capillary rheometer, thermal analysis equipment, torsion pendulum, and
dielectric polarization apparatus. The third section is more general in
nature and covers various aspects of computer use for mathematical mod
eling. Some of the topics covered are degradation kinetics, solution prop
erties, water/cosolvent evaporation, emulsification, heat capacity data
bank, master plots for vibration damping, and the use of experimental
design and analysis.
This book has brought together representative uses of computer sci
ence and technology in the field of applied polymer science. It is hoped
that this book will spur further activity in this area.
The editor wishes to thank the authors for their effective oral and
written communications and the reviewers for their critiques and con
structive comments.
THEODORE PROVDER
Glidden Coatings and Resins
Strongsville, OH 44136
May 7, 1982
ix
In Computer Applications in Applied Polymer Science; Provder, T.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
1
Control of an Isothermal Polystyrene Reactor
D. C. TIMM, R. E. GILBERT, T. T. KO,1 and M. R. SIMMONS2
University of Nebraska, Department of Chemical Engineering, Lincoln, NE 68588
Over the past te
made an extensiv
polymerization of styrene initiated by n-butyl-
lithium. As part of that work, descriptive dynamic
equations have been derived. Viewed as a control
problem, input variables for the system are the
flow rates, the input initiator concentration, and
the input monomer concentration. The primary out­
puts are the number average molecular weight and
the production rate of polymer. Since there are
two outputs and three inputs, the control matrix
is not square. In order to deal with this situa­
tion, a decoupling matrix is added upstream of the
process. Decoupling is accomplished according to a
steady-state optimal policy. After decoupling, the
non-linear system is simulated on the digital com­
puter and placed under closed loop negative feed­
back control. Results are presented for propor­
tional and for proportional-plus-integral control.
Polymerization reactions require stringent operating condi­
tions for continuous production of quality resins. In this paper
the chain-growth polymerization of styrene initiated with n-
butyllithium in the presence of a solvent is described. A per­
fectly mixed isothermal, constant volume reactor is employed.
Coupled kinetic relationships descriptive of the initiator, mono­
mer, polystyryl anion and polymer mass concentration are simula­
ted. Trommsdorff effects (1) are incorporated. Controlled vari­
ables include number average molecular weight and production rate
of total polymer. Manipulated variables are flow rate, input
monomer concentration, and input initiator concentration. The
1 Current address: Mostek Corporation, Dallas, TX

2 Current address: Texas Instruments, Inc., Dallas, TX
0097-6156/82/0197-0003$06.00/0
© 1982 American Chemical Society
In Computer Applications in Applied Polymer Science; Provder, T.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
4 COMPUTER APPLICATIONS IN APPLIED POLYMER SCIENCE
controller uncouples the controlled variables so as to produce an
optimal operating policy at steady state.
Polymerization Dynamics
Timm and co-workers (2, _3, 4) have developed the following
descriptive model for this system. The medium viscosity has a
significant effect on the rate of initiation.
T = -QT/V + K MIb rilol polymer/liter/min
±
M = Q (M. - M)/V - K AM mol monomer/liter/min
in p
I = Q (I. - I)/V
m I
1_
W = M K MI + M K MT - QW/V gm polymer/liter/min
o ± Q
eq eq
A = ((1 + 4K T) 2 - 1)/2K morly l unaansisoonc/ilaitteedr polysty-
y = y + 2.059-10 13W3'684/T1-125 centipoise
Q
K = K° y - .0002
P P
K = K° y - .2025 (1)
eq eq
A space vector y, an input vector x, and a controlled vari­
able vector c are defined as
y = (T,M,I,W)t x = (Q,I. ,M. ) t c = (MW.S)* (2)
in i n
The number average molecular weight and the production rate in
the controlled vector are defined as MW = W/T and S = QW.
Direct simulation of these non-linear equations will be des­
cribed later. For control analysis, however, i t is much more
convenient to linearize them about a reference steady state.
This reference state (see Table I) was one of several experimen­
tally observed states. The linearization is straight-forward.
The results are
y + Ay = Bx and c = Dy + Ex (3)
where y and x represent deviations from the steady-state values
of y and x. The matrices A,B,D, and E were determined by Ko (5)
and are listed in Table II. Note that the off-diagonal elements
of A indicate significant dynamic and steady-state interactions
among the state variables.
In Computer Applications in Applied Polymer Science; Provder, T.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.
1. TIMMETAL. Isothermal Polystyrene Reactor 5
TABLE I
Steady State Conditions
Q = .016710 liter/min A - .0073289 g mole/liter
I. = .02009 mol/liter MW = 41416.54 gram/g mole
in
M. = 3.264 mol/liter S = 10.641 gram/min
in
T .015368 mol/liter K = 12.3287 liter/g mole/min
P
M .35370 mol/liter K = 149.6674 liter/g mole
eq
I .0047221 mol/liter P = 1643.48 centipoise
W = 636.485 gm/liter
In Computer Applications in Applied Polymer Science; Provder, T.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1982.