ASTM D6342-08
(Practice)Standard Practice for Polyurethane Raw Materials: Determining Hydroxyl Number of Polyols by Near Infrared (NIR) Spectroscopy
Standard Practice for Polyurethane Raw Materials: Determining Hydroxyl Number of Polyols by Near Infrared (NIR) Spectroscopy
SIGNIFICANCE AND USE
General Utility:
It is necessary to know the hydroxyl number of polyols in order to formulate polyurethane systems.
This practice is suitable for research, quality control, specification testing, and process control.
Limitations:
Factors affecting the NIR spectra of the analyte polyols need to be determined before a calibration procedure is started. Chemical structure, interferences, any nonlinearities, the effect of temperature, and the interaction of the analyte with other sample components such as catalyst, water and other polyols needs to be understood in order to properly select samples that will model those effects which can not be adequately controlled.
Calibrations are generally considered valid only for the specific NIR instrument used to generate the calibration. Using different instruments (even when made by the same manufacturer) for calibration and analysis can seriously affect the accuracy and precision of the measured hydroxyl number. Procedures used for transferring calibrations between instruments are problematic and are to be utilized with caution following the guidelines in Section 16. These procedures generally require a completely new validation and statistical analysis of errors on the new instrument.
The analytical results are statistically valid only for the range of hydroxyl numbers used in the calibration. Extrapolation to lower or higher hydroxyl values can increase the errors and degrade precision. Likewise, the analytical results are only valid for the same chemical composition as used for the calibration set. A significant change in composition or contaminants can also affect the results. Outlier detection, as discussed in Practices E 1655, is a tool that can be used to detect the possibility of problems such as those mentioned above.
SCOPE
1.1 This standard covers a practice for the determination of hydroxyl numbers of polyols using NIR spectroscopy.
1.2 Definitions, terms, and calibration techniques are described. Procedures for selecting samples, and collecting and treating data for developing NIR calibrations are outlined. Criteria for building, evaluating, and validating the NIR calibration model are also described. Finally, the procedure for sample handling, data gathering and evaluation are described.
1.3 The implementation of this standard requires that the NIR spectrometer has been installed in compliance with the manufacturer's specifications.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Note 1—There is no equivalent or similar ISO standard.
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Designation: D6342 − 08
StandardPractice for
Polyurethane Raw Materials: Determining Hydroxyl Number
1
of Polyols by Near Infrared (NIR) Spectroscopy
This standard is issued under the fixed designation D6342; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* E222 Test Methods for Hydroxyl Groups Using Acetic
Anhydride Acetylation
1.1 This standard covers a practice for the determination of
E275 Practice for Describing and Measuring Performance of
hydroxyl numbers of polyols using NIR spectroscopy.
Ultraviolet and Visible Spectrophotometers
1.2 Definitions, terms, and calibration techniques are de-
E456 Terminology Relating to Quality and Statistics
scribed. Procedures for selecting samples, and collecting and
E1655 Practices for Infrared Multivariate Quantitative
treating data for developing NIR calibrations are outlined.
Analysis
Criteria for building, evaluating, and validating the NIR
E1899 Test Method for Hydroxyl Groups Using Reaction
calibration model are also described. Finally, the procedure for
with p-ToluenesulfonylIsocyanate(TSI)andPotentiomet-
sample handling, data gathering and evaluation are described.
ric Titration with Tetrabutylammonium Hydroxide
1.3 The implementation of this standard requires that the
3. Terminology
NIR spectrometer has been installed in compliance with the
manufacturer’s specifications.
3.1 Definitions—Terminology used in this practice follows
that defined in Terminology D883. For terminology related to
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the molecular spectroscopy methods, refer to Terminology E131.
For terms relating to multivariate analysis, refer to Practice
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- E1655.
bility of regulatory limitations prior to use.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 hydroxyl number—the milligrams of potassium hy-
NOTE 1—There is no equivalent or similar ISO standard.
droxide equivalent to the hydroxyl content of1gof sample.
2. Referenced Documents
4. Summary of Practice
2
2.1 ASTM Standards:
4.1 Multivariate mathematics is applied to correlate the NIR
D883 Terminology Relating to Plastics
absorbance values for a set of calibration samples to the
D4274 Test Methods for Testing Polyurethane Raw Materi-
respective reference hydroxyl number for each sample. The
als: Determination of Hydroxyl Numbers of Polyols
resultant multivariate calibration model is then applied to the
D4855 Practice for Comparing Test Methods (Withdrawn
3
analysis of unknown samples to provide an estimate of their
2008)
hydroxyl numbers.
E131 Terminology Relating to Molecular Spectroscopy
E168 Practices for General Techniques of Infrared Quanti-
4.2 Multilinear regression (MLR), principal components
tative Analysis
regression (PCR), and partial least squares regression (PLS)
are the mathematical techniques used for the development of
the calibration model.
1
This practice is under the jurisdiction ofASTM Committee D20 on Plastics and
4.3 Statistical tests are used to detect outliers during the
is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plastics
development of the calibration model. Outliers can include
and Elastomers.
high leverage samples and samples whose hydroxyl numbers
Current edition approved March 1, 2008. Published April 2008. Originally
approved in 1998. Last previous edition approved in 2003 as D6342 - 98(2003).
are inconsistent with the model.
DOI: 10.1520/D6342-08.
2
4.4 Validation of the calibration model is performed by
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
using the model to analyze a set of validation samples. The
Standards volume information, refer to the standard’s Document Summary page on
hydroxyl number estimates for the validation set are statisti-
the ASTM website.
3
cally compared to the reference hydroxyl number for this set to
The last approved version of this historical standard is referenced on
www.astm.org. test for agreement of the model with the reference method.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D6342 − 08
4.5 Statistical expressions are given for calculating the solid-state semiconductors. PbS, PbSe, and InGaAs d
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D6342–98 (Reapproved 2003) Designation: D 6342 – 08
Standard Practice for
Polyurethane Raw Materials: Determining Hydroxyl Number
1
of Polyols by Near Infrared (NIR) Spectroscopy
This standard is issued under the fixed designation D 6342; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This standard covers a practice for the determination of hydroxyl numbers of polyols using NIR spectroscopy.
1.2 Definitions, terms, and calibration techniques are described. Procedures for selecting samples, and collecting and treating
data for developing NIR calibrations are outlined. Criteria for building, evaluating, and validating the NIR calibration model are
also described. Finally, the procedure for sample handling, data gathering and evaluation are described.
1.3 The implementation of this standard requires that the NIR spectrometer has been installed in compliance with the
manufacturer’s specifications.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
NOTE 1—There is no equivalent or similar ISO standard.
2. Referenced Documents
2
2.1 ASTM Standards:
D 883 Terminology Relating to Plastics
D 4274 Test Methods for Testing Polyurethane Raw Materials: Determination of Hydroxyl Numbers of Polyols
D 4855 Practice for Comparing Test Methods
E 131 Terminology Relating to Molecular Spectroscopy
E 168 Practices for General Techniques of Infrared Quantitative Analysis
E222Hydroxyl Groups Using Acetic Anhydride Acetylation 222 Test Methods for Hydroxyl Groups Using Acetic Anhydride
Acetylation
E 275 Practice for Describing and Measuring Performance of Ultraviolet, Visible, and Near-Infrared Spectrophotometers
E 456 Terminology Relating to Quality and Statistics
E 1655Practices for Infrared, Multivariate, Quantitative Analysis Practices for Infrared Multivariate Quantitative Analysis
E1899Hydroxyl Groups by Toluenesulfonyl Isocyanate 1899 Test Method for Hydroxyl Groups Using Reaction with
p-Toluenesulfonyl Isocyanate (TSI) and Potentiometric Titration with Tetrabutylammonium Hydroxide
3. Terminology
3.1 Definitions— Terminology used in this practice follows that defined in Terminology D 883. For terminology related to
molecular spectroscopy methods, refer to Terminology E 131. For terms relating to multivariate analysis, refer to Practice E 1655.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 hydroxyl number—the milligrams of potassium hydroxide equivalent to the hydroxyl content of1gof sample.
4. Summary of Practice
4.1 Multivariate mathematics is applied to correlate the NIR absorbance values for a set of calibration samples to the respective
referencehydroxylnumberforeachsample.Theresultantmultivariatecalibrationmodelisthenappliedtotheanalysisofunknown
samples to provide an estimate of their hydroxyl numbers.
4.2 Multilinear regression (MLR), principal components regression (PCR), and partial least squares regression (PLS) are the
1
This practice is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.22 on Cellular Materials— - Plastics
and Elastomers.
Current edition approved NovemberMarch 1, 2003.2008. Published December 2003.April 2008. Originally approved in 1998. Last previous edition approved in 19982003
as D 6342 - 98(2003).
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
D6342–08
mathematical techniques used for the development of the calibration model.
4.3 Statistical tests are used to detect outliers during the development of the calibration model. Outliers maycan include high
leverage samples and samples whose hydroxyl numbers are inconsistent with the model.
4.4 Validation of the
...
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