TA Instruments TMA 2940 User manual

TA I NSTRUMENTS TMA 2940 I
TMA 2940
Thermomechanical Analyzer
Operator’s Manual
PN 925615.001 Rev. D (Text and Binder)
PN 925615.002 Rev. D (Text Only)
Issued November 1999
TA Instruments
Thermal Analysis & Rheology
A S UBSIDIARY OF W ATERS C ORPORATION

TA I NSTRUMENTS TMA 2940 II
© 1995, 1996, 1997, 1999 by TA Instruments,
Inc.
109 Lukens Drive
New Castle, DE 19720
Notice
The material contained in this manual is be-
lieved adequate for the intended use of this
instrument. If the instrument or procedures are
used for purposes other than those specified
herein, confirmation of their validity and
suitability must be obtained from TA Instru-
ments, Inc. Otherwise, TA Instruments does not
guarantee results and assumes no obligation or
liability. This publication is not a license to
operate under nor a recommendation to infringe
upon any process patents.
TA Instruments TA Operating Software and
Instrument, Data Analysis, and Utility Software
and their associated manuals are proprietary and
copyrighted by TA Instruments, Inc. Purchasers
are granted a license to use these software
programs on the instrument and controller with
which they were purchased. These programs
may not be duplicated by the purchaser without
the prior written consent of TA Instruments.
Each licensed program shall remain the exclu-
sive property of TA Instruments, and no rights
or licenses are granted to the purchaser other
than as specified.

TA I NSTRUMENTS TMA 2940 III
Table of Contents
Notes, Cautions, and Warnings ................. xi
Safety........................................................... xii
Instrument Symbols............................... xii
Electrical Safety ................................... xiii
Handling Liquid Nitrogen .................... xiii
Lifting the Instrument ...........................xvi
Using This Manual................................... xvii
CHAPTER 1: Introducing
the TMA 2940............................................ 1-1
Introduction.................................................1-3
Components.......................................... 1-3
The 2940 Instrument...................................1-5
2940 Display ........................................1-7
2940 Keypad ........................................1-7
HEATER Switch.......................... 1-11
POWER Switch .......................... 1-11
Accessories ...............................................1-12
Standard Accessories .........................1-12
Optional Accessories.......................... 1-13
Specifications............................................ 1-14

TA I NSTRUMENTS TMA 2940 IV
Table of Contents
(continued) CHAPTER 2: Installing
the TMA 2940............................................ 2-1
Unpacking/Repacking the TMA 2940........ 2-3
Unpacking the TMA ............................ 2-3
Removing the Shipping Material ......... 2-6
Repacking the 2940.............................. 2-8
Installing the Instrument .............................2-9
Inspecting the System...........................2-9
Choosing a Location .......................... 2-10
Installing the Thermocouple .............. 2-11
Installing the Weight Tray Door ........ 2-13
Installing the Stage............................. 2-14
Installing the Expansion/
Penetration Probes.............................. 2-18
Installing a Probe .........................2-18
Removing a Probe........................ 2-19
Connecting Cables, Gas Lines,
and Isolation Transformer.................. 2-20
GPIB Cable.................................. 2-20
Purge Line.................................... 2-23
Air Cool Line...............................2-25
Power Cable................................. 2-26
Isolation Transformer .................. 2-27

TA I NSTRUMENTS TMA 2940 V
Table of Contents
(continued)
Starting the 2940....................................... 2-29
Shutting Down the 2940 ........................... 2-31
CHAPTER 3: Running
Experiments............................................... 3-1
Overview..................................................... 3-3
Before You Begin ................................3-4
Calibrating the TMA ..................................3-5
Force Calibration.................................. 3-5
Probe Calibration .................................3-6
Temperature Calibration ...................... 3-7
Cell Constant........................................ 3-9
Running a TMA Experiment .................... 3-10
Experimental Procedure..................... 3-10
Selecting a Probe ................................ 3-11
Zeroing the Auto Measure System..... 3-12

TA I NSTRUMENTS TMA 2940 VI
Table of Contents
(continued) Sample Preparation and Loading ....... 3-13
Sample Preparation...................... 3-13
Sample Loading........................... 3-13
Thermocouple Positioning ................. 3-15
Measuring the
Sample Length ...................................3-15
Setting Up an Experiment .................. 3-16
Setting Up Accessories ...................... 3-17
Using Air Cool.............................3-17
Using a Purge Gas .......................3-18
Suggestions ...........................3-18
Starting an Experiment....................... 3-20
Stopping an Experiment..................... 3-20
Removing Samples ...................... 3-20
Subambient Experiments .......................... 3-22
Performing a Cooling Experiment ..... 3-22
Techniques for Improved
Subambient Operation........................ 3-23

TA I NSTRUMENTS TMA 2940 VII
Table of Contents
(continued)
CHAPTER 4: Using
Your Options.............................................4-1
Overview..................................................... 4-3
Film/Fiber Accessory.................................. 4-4
Description ...........................................4-4
Operating Procedures........................... 4-5
Accessory Installation .......................... 4-5
Removing the Existing Probe ........ 4-6
Removing the Stage.......................4-6
Changing the Instrument Mode..... 4-7
Installing the Film/Fiber Probe .....4-7
Installing the Film/Fiber Stage...... 4-8
Calculating the Offset....................4-9
Calibration..........................................4-11
Sample Preparation ............................ 4-12
Using the Aluminum Balls ..........4-12
Using the Stainless
Steel Clamps ................................ 4-14
Flexure Accessory ....................................4-17
Description .........................................4-17
Accessory Installation ........................ 4-18
Calibration.......................................... 4-18
Sample Preparation ............................4-19

TA I NSTRUMENTS TMA 2940 VIII
Table of Contents
(continued)
Dilatometer Accessory.............................. 4-21
Description .........................................4-21
Operating Procedures......................... 4-23
Considerations .............................4-23
Accessory Installation ........................ 4-23
Calibration.......................................... 4-24
Baseline Calibration .................... 4-24
Displacement Calibration ............ 4-25
Sample Preparation ............................ 4-26
Parallel Plate Rheometer Accessory......... 4-29
Description .........................................4-29
Accessory Installation ........................ 4-29
Calibration.......................................... 4-30
Sample Preparation ............................ 4-31
Sample Encapsulating Press ........ 4-31
Preparing Moldable Powders ...... 4-35
Preparing Resinous Materials...... 4-38
Preparing Sheet Materials............4-40
Sample Loading .................................4-41
Cleanup ........................................ 4-42

TA I NSTRUMENTS TMA 2940 IX
Table of Contents
(continued)
Calculations........................................ 4-43
Hemispherical Probe................................. 4-47
CHAPTER 5: Technical
Reference ................................................... 5-1
Description of the TMA 2940 ................... 5-3
Uses of
Thermomechanical Analysis ................ 5-4
Calculating the
Coefficient of Expansion .....................5-5
Method Considerations...............................5-6
Status Codes ...............................................5-7
CHAPTER 6: Maintenance
and Diagnostics ......................................... 6-1
Overview..................................................... 6-3
Routine Maintenance .................................. 6-4
Inspection .............................................6-4
Cleaning ...............................................6-5
Cleaning the Keypad .....................6-5
Cleaning the Probe Assembly........ 6-5
Cleaning the Stage .........................6-6
Cleaning the Thermocouple...........6-7

TA I NSTRUMENTS TMA 2940 X
Table of Contents
(continued)
Replacements .......................................6-8
Installing a New Thermocouple .... 6-8
Diagnostics .................................................6-9
Fuses..................................................... 6-9
Power Failures.................................... 6-10
TMA 2940 Test Functions........................ 6-12
The TMA Confidence Test ................ 6-12
Replacement Parts .................................... 6-15
APPENDIX A: Ordering
Information .............................................. A-1
INDEX ........................................................I-1

TA I NSTRUMENTS TMA 2940 XI
Notes, Cautions,
and Warnings
This manual uses NOTES, CAUTIONS, and
WARNINGS to emphasize important and
critical instructions under the guidelines de-
scribed below:
Highlights important information about equipment
or procedures.
Emphasizes a procedure that may damage
equipment or cause loss of data if not followed
correctly.
Marks a procedure that may be hazardous to
the operator or to the environment if not
followed correctly.
! WARNING
NOTE:
tt
tt
t CAUTION:

TA I NSTRUMENTS TMA 2940 XII
Safety
Instrument Symbols
The following labels are displayed on the TMA
2940 instrument for your protection:
Symbol Explanation
This symbol, which
appears on the furnace
enclosure and on the stage
can of the TMA 2940,
indicates that a hot
surface may be present.
Take care not to touch
these areas or allow any
material that may melt or
burn to come in contact
with these hot surfaces.
Please heed the warning labels and take the
necessary precautions when dealing with those
parts of the instrument. The TMA 2940
Operator's Manual contains cautions and
warnings that must be followed for your own
safety.

TA I NSTRUMENTS TMA 2940 XIII
Electrical Safety
Voltages exceeding 110 Vac are present in this
system. Always unplug the instrument before
performing any maintenance.
Because of the high voltages in this instru-
ment, untrained personnel must not remove
the cabinet cover unless specifically directed
to do so in the manual. Maintenance and
repair of internal parts must be performed by
TA Instruments, Inc. or other qualified service
personnel only.
After transport or storage in humid condi-
tions, this equipment could fail to meet all the
safety requirements of the safety standards
indicated. Refer to the NOTE on page 2-11 for
the method of drying out the equipment before
use.
Handling Liquid Nitrogen
The TMA 2940 can use the cryogenic (low-
temperature) agent, liquid nitrogen, for cooling
in subambient experiments. Because of its low
temperature (-195°C), liquid nitrogen will burn
the skin. Use extreme caution when working
with liquid nitrogen and other cryogenic materi-
als to ensure that you do not burn yourself.
Personnel working with liquid nitrogen should
take the following precautions.
Liquid nitrogen evaporates rapidly at room
temperature. Be certain that areas where
liquid nitrogen is used are well ventilated to
prevent depletion of oxygen in the air.
! WARNING
! WARNING
! WARNING

TA I NSTRUMENTS TMA 2940 XIV
1. Wear goggles or a face shield, gloves that
are large enough to be removed easily, and a
rubber apron. For extra protection, wear
high-topped, sturdy shoes, and leave your
pant legs outside the shoe tops.
2. Transfer the liquid slowly to prevent thermal
shock.
3. Use containers having adequate low-
temperature properties. Ensure that closed
containers have vents to relieve pressure;
liquid nitrogen evaporates rapidly at room
temperature.
4. The purity of liquid nitrogen alters as it
evaporates. If much of the liquid in the
container has evaporated, check the remain-
ing liquid before using it for any purpose in
which high oxygen content is dangerous.
IF BURNED BY LIQUID NITROGEN...
1. Flood the area (skin or eyes) with large
quantities of cool water IMMEDIATELY;
then apply cold compresses.
2. See a doctor IMMEDIATELY if the skin is
blistered or if there is a chance of eye
infection.

TA I NSTRUMENTS TMA 2940 XV
Potential Asphyxiant
Liquid nitrogen can cause rapid suffocation without
warning.
Store and use in an area with adequate ventilation.
Do not vent LNCA container in confined spaces.
Do not enter confined spaces where nitrogen gas
may be present unless the area is well ventilated.
The warning above applies to the use of liquid nitrogen. Oxygen
depletion sensors are sometimes utilized where liquid nitrogen is
in use. Please refer to the “Safety” section of the
TA Instru-
ments Liquid Nitrogen Cooling Accessory
manual for more de-
tailed instructions regarding the use of the LNCA.
! WARNING

TA I NSTRUMENTS TMA 2940 XVI
Lifting the Instrument
The TMA 2940 is a fairly heavy instrument. In
order to avoid injury, particularly to the back,
please follow this advice:
Use two people to lift and/or carry the
instrument. The instrument is too heavy for
one person to handle safely.
! WARNING

TA I NSTRUMENTS TMA 2940 XVII
Using This Manual
CHAPTER 1 Introduces the TMA 2940
and lists its specifications.
CHAPTER 2 Describes how to install
and assemble your TMA
2940.
CHAPTER 3 Describes routine opera-
tion of the TMA instru-
ment, including subambi-
ent operations.
CHAPTER 4 Contains the procedures
used to operate the TMA
with the optional accesso-
ries.
CHAPTER 5 Explains the technical
aspects of the TMA and
its operation.
CHAPTER 6 Provides maintenance and
diagnostic procedures.
Appendix A Lists TA Instruments
offices that you can
contact to place orders,
receive technical assis-
tance, and request service.
Index Contains an alphabetical
list of topics and page
number references.

TA I NSTRUMENTS TMA 2940 XVIII

TA I NSTRUMENTS TMA 2940 1–1
CHAPTER 1: Introducing the
TMA 2940
Introduction.................................................1-3
Components.......................................... 1-3
The 2940 Instrument...................................1-5
2940 Display ........................................1-7
2940 Keypad ........................................1-7
HEATER Switch .......................... 1-11
POWER Switch .......................... 1-11
Accessories ...............................................1-12
Standard Accessories .........................1-12
Optional Accessories.......................... 1-13
Specifications............................................ 1-14

Introduction
1–2 TA I NSTRUMENTS TMA 2940