ASTM D5017-96

Standard Test Method for Determination of Linear Low Density Polyethylene (LLDPE) Composition by Carbon-13 Nuclear Magnetic Resonance

SCOPE
1.1 This test method determines the molar composition of copolymers prepared from ethylene (ethene) and a second alkene-1 monomer. This second monomer can include propene, butene-1, hexene-1, octene-1, and 4-methylpentene-1.  
1.2 Calculations of this test method are valid for products containing units EEXEE, EXEXE, EXXE, EXXXE, and of course EEE where E equals ethene and X equals alkene-1. Copolymers containing a considerable number of alkene-1 blocks (such as, longer blocks than XXX) are outside the scope of this test method.  
1.3 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. See Section 8 for a specific hazard statement.

General Information

• Status: Historical
• Publication Date: 09-Dec-1996
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.70 - Analytical Methods

Relations

• Replaced By: ASTM D5017-96(2003)e1 - Standard Test Method for Determination of Linear Low Density Polyethylene (LLDPE) Composition by Carbon-13 Nuclear Magnetic Resonance
• Effective Date: 10-Jun-2003

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 5017 – 96
Standard Test Method for
Determination of Linear Low Density Polyethylene (LLDPE)
Composition by Carbon-13 Nuclear Magnetic Resonance
This standard is issued under the fixed designation D 5017; 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 3. Terminology
1.1 This test method determines the molar composition of 3.1 Some units, symbols, and abbreviations used in this test
copolymers prepared from ethylene (ethene) and a second method are summarized in Practices E 380 and E 386. Other
alkene-1 monomer. This second monomer can include propene, abbreviations are listed as follows:
butene-1, hexene-1, octene-1, and 4-methylpentene-1. 3.2 Abbreviations:Abbreviations:
1.2 Calculations of this test method are valid for products 3.2.1 C—carbon 13,
containing units EEXEE, EXEXE, EXXE, EXXXE, and of 3.2.2 LLDPE—linear low-density polyethylene,
course EEE where E equals ethene and X equals alkene-1. 3.2.3 ODCB—ortho-dichlorobenzene,
Copolymers containing a considerable number of alkene-1 3.2.4 F1—transmitter frequency,
blocks (such as, longer blocks than XXX) are outside the scope 3.2.5 T1—relaxation time, and
of this test method. 3.2.6 TR—pulse repetition time.
1.3 This standard does not purport to address all of the 3.3 Definitions of Terms Specific to This Standard:
safety concerns, if any, associated with its use. It is the 3.3.1 With a few modifications, terms used to designate
responsibility of the user of this standard to establish appro- different carbon types were suggested by Carman. Methine
priate safety and health practices and determine the applica- carbons are identified by CH and branch carbons are labeled
bility of regulatory limitations prior to use. See Section 8 for a according to branch type as summarized in Table 1. Branch
specific hazard statement. carbons are numbered starting with the methyl as number one.
3.3.2 Backbone methylene carbons are designated by a pair
NOTE 1—There is no equivalent ISO standard.
of Greek letters that specify the location of the nearest methine
carbon in each direction. For example, a,a-methylene carbon
2. Referenced Documents
+
is between two methine carbons or an a,d methylene carbon
2.1 ASTM Standards:
has one immediate methine neighbor and the second methine
E 177 Practice for Use of the Terms Precision and Bias in
2 carbon is located at least four carbons away.
ASTM Test Methods
E 380 Practice for Use of the International System of Units
4. Summary of Test Method
(SI)
4.1 Polymer samples are dispersed in hot solvent and
E 386 Practice for Data Presentation Relating to High-
analyzed at high temperatures using Carbon-13 nuclear mag-
Resolution Nuclear Magnetic Resonance (NMR) Spectros-
netic resonance (NMR) spectroscopy.
copy
4.2 Spectra are recorded under conditions such that the
E 691 Practice for Conducting an Interlaboratory Study to
response of each chemically different carbon is identical.
Determine the Precision of a Test Method
Integrated responses for carbons originated from the different
comonomers are used for calculation of the copolymer com-
position.
This test method is under the jurisdiction of ASTM Committee D-20 on Plastics
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Current edition approved Dec. 10, 1996. Published May 1997. Originally
published as D 5017 – 91. Last previous edition D 5017 – 91.
This revision includes the addition of an ISO equivalency statement and an
update of model numbers of referenced NMR instruments.
2 4
Annual Book of ASTM Standards, Vol 14.02. Carman, C. J., Harrington, R. A., and Wilkes, C. E., Macromolecules 1977, Vol
Annual Book of ASTM Standards, Vol 14.01. 10, p. 536.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D5017–96
TABLE 1 Designations for Different Carbon Types
9.7 Apodisation, 2 (exponential) Hz
−1
Monomer Branch Type Label 9.8 Pulse width, <[4 3 sweep width Hz]
9.9 Decoupling, complete
Propane (P) methyl M1
Butene-1 (B) ethyl E1–E2
NOTE 6—The nuclear overhauser enhancement for the carbons used for
Hexene-1 (H) butyl B1–B4
4, 6 , 7
quantitative analysis have been shown to be full.
4-Methylpentene-1 (MP) isobutyl IB1–IB3
Octene-1 (O) hexyl H1–H6
10. Procedure
10.1 Weigh a 1.2-g sample into a 10-mm NMR tube. Add
1.5 mL of solvent (7.1) and 1.3 mL deuterated solvent (7.2) to
5. Significance and Use
the tube. Cap the tube.
5.1 Performance properties are dependent on the number
and type of short chain branches. This test method permits NOTE 7—Solution concentration can be varied with instruments of
different field strength as long as one meets the minimum signal-to-noise
measurement of these branches for ethylene copolymers with
requirement of 9.4.
propylene, butene-1, hexene-1, octene-1, and
4-methylpentene-1.
10.2 Homogenize the sample in an oven at 150°C for 3 to 4
h. Keep the tube in an almost horizontal position during the
6. Apparatus
heating step.
6.1 NMR Spectrometer, C pulse-Fourier transform with
10.3 Set spectrometer parameters as detailed in Section 9.
field strength of at least 2.35 T. Typical instruments include the
10.4 Transfer the tube to the NMR spectrometer and equili-
Jeol GSX-400, Bruker Avance OPX-300, and Varian 400 Unity brate 10 to 15 min at 130°C.
PLUS spectrometers.
10.5 Scan the sample with complete broadband decoupling
using the parameters of Section 9.
NOTE 2—The system should have a computer size of at least 32 K for
10.6 Record the spectrum and the accurate full-scale inte-
50-MHz carbon frequency with digital resolution of at least 0.5 Hz/point
gral from 10 to 50 ppm. Adjust partial integrals so that integral
in the final spectrum.
of the second largest peak in the spectrum is at least 50 % of
6.2 Sample Tubes, 10-mm outside diameter.
full-scale. This partial integral must be flat before and after the
NOTE 3—Sample tube size can be varied; however, the sample prepa-
area to be measured.
ration procedure described in 10.1 may need to be altered to maintain the
NOTE 8—The combination of sample preparation time and acquisition
minimum signal-to-noise requirement of 9.4.
time necessary to obtain the signal-to-noise requirement of 9.4 can lead to
prohibitively long experiments if samples are run multiplicatively. It is
7. Reagents and Materials
acceptable to perform sample determinations using a single analysis.
7.1 Ortho-dichlorobenzene or 1,2,4-trichlorobenzene, re-
Duplicate runs in accordance with 13.1 were performed for the round-
agent grade
robin exercise.
7.2 Deuterated o-dichlorobenzene or p-dichlorobenzene.
11. Calculation
This material is used at a concentration up to 20 % with the
reagent specified in 7.1 as an internal lock.
11.1 Measure the area between the appropriate integration
limits outlines in Annex A1.
8. Hazards
11.2 Substitute the integrals into the appropriate equations
8.1 Precaution: Solvents should be handled in a wellven-
from Annex A2 to calculate the mole percent alkene-1.
tilated fume hood.
11.3 Annex A3 gives a sample calculation for an ethylene-
octene copolymer using integrals and equations in accordance
9. Instrument Parameters
with 11.1 and 11.2.
9.1 Pulse angle, 90°
NOTE 9—With the prescribed repetition time (10 s) and pulse angle
9.2 Pulse repetition, 10 s
(90°), the maximum allowable relaxation time (T ) for carbons used for
9.3 Sample temperature, 130°C
quantitative analysis is 2 s. To shorten the analysis time, a shorter pulse
repetition time can be used if one accounts for the relaxation time
NOTE 4—The precise temperature should be measured using the NMR
6 differences. Relaxation times of carbons for the five copolymers were
thermometer (cyclooctane/methylene iodide).
determined at a carbon frequency of 50 MHz using the inversion recovery
,
8 9
9.4 Minimum signal-to-noise, 5000:1
method. Annex A4 summarizes these relaxation times and correction
factors (reciprocal of the relative intensities) for a 4-s repetition time (T ).
R
NOTE 5—The signal-to-noise ratio is defined as 2.5 times the signal
With the shorter T , multiply integrals by these correction factors before
R
intensity of the 30.0-ppm peak (isolated methylenes) divided by the peak
using the equations in Annex A2. The T values would have to be
to peak noise for the region from 50 to 70 ppm. Calculation of
remeasured for analyses performed at spectrometer frequencies other than
signal-to-noise is permitted using an equivalent software procedure.
50 MHz.
9.5 Sweep width, 175 ppm
9.6 Transmitter frequency (F1), 50 to 55 ppm
Randall, J. C., “NMR and Macromolecules,” Chapter 9, American Chemical
Society Symposium Series 247, 1984.
Farrar, T. C., and Becker, E. D., Pulse and Fourier Transform NMR, Chapter 2,
Available from Wilmad Scientific Glass Co. Academic Press, New York, 1971.
6 9
Vidrime, D. W., and Peterson, P. E., Analytical Chemistry, Vol 48, 1976, p. Cheng, H. N., and Bennet, M. A., Macromolecule Chemistry, Vol 188, 1987,
1301. pp. 2665–2677.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D5017–96
11.4 If desired, convert results from mole percent alkene-1 were prepared at one source, but the individual specimens were
to branches per 1000 carbons (br/1000C) using the equations in prepared at the laboratories that tested them. Each “test result”
Annex A5. was the average of two individual determinations. Each labo-
ratory obtained one test result for each material.
12. Report
NOTE 10—Caution: The following explanations of r and R (13.2-
12.1 Report the mole percent alkene from 11.2 or branches/
13.2.3) are only intended to present a meaningful way of considering the
1000C from 11.4, or both.
approximate precision of this test method. The data in Table 2 should not
be rigorously applied to acceptance or rejection of material, as those data
13. Precision and Bias
are specific to the round robin and may not be representative of other lots,
13.1 Table 2 is based on a round robin conducted in 1988 conditions, materials, or laboratories. Users of this test method should
apply the principles outlined in Practice E 691 to generate data specific to
in accordance with Practice E 691, involving nine materials
their laboratory and materials, or between specific laboratories. The
tested by six laboratories. For each material, all the samples
principles of 13.2-13.2.3 would then be valid for such data.
13.2 Concept of r and R—If S and S have been calculated
r R
Supporting data are available from ASTM Headquarters. Request RR: D-20-
from a large enough body of data, and for test results that were
1192.
averages from testing two specimens:
13.2.1 Repeatability—Two test results obtained within one
TABLE 2 Precision Statistics for Determination of Mole Percent
laboratory shall be judged not equivalent if they differ by more
Branching in LLDPE Copolymers by Carbon-13 NMR
Spectroscopy than the “r” value for that material; “r” is the interval
representing the critical difference between two test results for
Expressed as % of the Average
Average
Sample Comonomer
the same material, obtained by the same operator using the
Mole,% A B C D
V V r R
r R
same equipment on the same day in the same laboratory.
A butene 4.72 11.1 11.5 31.1 32.2
13.2.2 Reproducibility Limit, R (Comparing Two Test Re-
B butene 4.22 11.9 11.9 33.3 33.3
C hexene 3.64 17.1 18.2 47.9 51.0
sults for the Same Material, Obtained by Different Operators
D hexene 4.03 14.3 14.3 40.0 40.0
Using Different Equipment in Different Laboratories)—The
E octene 5.18 10.3 10.3 28.8 28.8
two test results should be judged not equivalent if they differ by
F octene 0.76 27.5 40.6 77.0 113.7
G 4-methyl-pentene 5.00 14.0 14.8 39.2 41.4
more than the “ R” value for that material.
H 4-methyl-pentene 1.26 37.4 38.2 104.7 107.0
13.2.3 Any judgment in accordance with 13.2.1 or 13.2.2
I propene 15.96 7.3 7.6 20.4 21.3
would have an approximate 95 % (0.95) probability of being
A
V = within laboratory coefficient of variation for the indicated material. It is
r
correct.
obtained by pooling the within laboratory standard deviations of the following test
results:
13.3 There are no recognized standards by which to esti-
2 2 2 ½
Sr 5 ( s 1 s . 1 s /n
@@ ~ ! ~ ! ~ ! # #
1 2 n
mate bias of this test method.
Vr 5 1003~Sr divided by the overall average for the material!.
B
V = between laboratories reproducibility, expressed as coefficient of varia-
R
tion, for the indicated material.
14. Keywords
C
r = within laboratory repeatability limit = 2.8 3 V .
r
D
R = between laboratories reproducibility limit = 2.8 3 V . 14.1 carbon-13 NMR; composition; LLDPE; polyethylene
R
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D5017–96
ANNEXES
(Mandatory Information)
A1. AREA BETWEEN THE APPROPRIATE INTEGRATION LIMITS OUTLINES
A
TABLE A1.1 Integration Limits for Ethylene Copolymers
Copolymer Area Region, ppm
Ethene-propene A 47.5 to 44.5
B 39.8 to 36.8
C 35.5 to 32.5
C+D+E 35.5 to 25.8
F 25.8 to 23.8
G 22.5 to 18.5
H Peak at 21.6
Ethene-butene-1 A 41.5 to 38.5
A8 Peak at 39.4
B 37.8 to 36.8
C 36.0 to 33.2
D + E 33.2 to 25.5
F 25.2 to 24.0
Ethene-hexene-1 A 41.5 to 40.5
B 40.5 to 39.5
C 39.5 to 37.0
D Peak at 35.8
D + E 36.8 to 33.2
F + G 33.2 to 25.5
G 28.5 to 26.5
H 24.9 to 24.1
Ethene-octene-1 A 41.5 to 40.5
B 40.5 to 39.5
C 39.5 to 37.0
D Peak at 35.8
D + E 36.8 to 33.2
F+G+H 33.2 to 25.5
H 28.5 to 26.5
I 25.0 to 24.0
P 24.0 to 22.0
Ethene-4-methylpentene-1 A 46.5 to 43.5
B 43.0 to 41.8
C 41.8 to 40.5
D 37.5 to 34.2
E Peak at 33.7
F + G 33.2 to 25.2
G 28.0 to 25.2
H Peak at 24.1
A
Isolated methylene carbons at 30.0 ppm.
A2. EQUATIONS FOR CALCULATING MOLE % COMPOSITION
A2.1 Ethene-Propene Copolymers A2.2 Ethene-Butene-1 Copolymers
A2.1.1 Moles Propene:
A2.2.1 Moles Butene-1:
B 5a2carbons: ~2A 1 B!/2 ~See Note A2.1!
(A2.3)
P 5a2 carbons: ~2A 1 B!/2 ~See Note A2.1! (A2.1)
B 5 CH carbons: ~A8 1 2C 1 2B!/4 (A2.3)
P 5 CH carbons: 2A 1 C 2 H (A2.1)
P8 5 average moles propylene: ~P 1 P !/2 (A2.1) B8 5 average moles butene21: ~B 1 B !/2
...