odor barrier characterization of polymer materials mocon 2008 internet seminar series june 11, 2008
Post on 16-Dec-2015
221 Views
Preview:
TRANSCRIPT
Odor Barrier Characterization ofOdor Barrier Characterization of Polymer Materials Polymer Materials
MOCON 2008 Internet Seminar Series
June 11, 2008
Background Information
A company needs to contain the odor generated from a waste process.
Background Information
The company has oxygen transmission rate equipment “in house”.
They want to know if this equipment can be used to screen potential barrier materials for their odor barrier properties.
The company requested a comparative study between different polymer film types.
Background Information
The Goal:
Compare odor barrier with oxygen barrier to determine if oxygen barrier property can be used for odor barrier prediction.
What’s Smelly?
Chemical and chemical reactions are responsible for odors.
Which chemicals does one choose to represent a particular odor?
Sensory testing – can help choose a consensus of the odor (i.e. good vs. bad) and descriptors.
GC testing can quantify the chemicals comprising the odor.
What’s Smelly?
Microanalytics performed an odor characterization study of the “Smelly” material.
They utilized a Multi-dimensional Gas Chromatograph with FID / PID / Olfactory / MS Detectors
AromaTrax Approach:An Integrated Analytical Approach to Studying Flavor/Aroma Interactions
Instrumentation / Techniques: Simultaneous Olfactory and Mass Spec Detection Multidimensional Gas Chromatography - Dean
Switch.Heart Cutting (Fractions), Cryogenic Trapping, Back Flushing
Inlet sampling techniques to maximize concentrations of aroma significant compounds.
Methods: Aroma Standard Profile SPME Aroma Extract Dilution Analysis (AEDA) Headspace Aroma Dilution Analysis (HADA)
Combining human sense with instruments and methods.
FID PID SniffPort
Mass Spectrometer Open Split Interface
AromaTrax Software
Chemstation(Agilent)
MultiTraxSoftware
Injectionsystem column 1 column 2
column 2
Agilent 6890 baseddual column MDGC
Windows NT
AromaTraxModel 2100 Multidimensional GC/O-MS
col 1col 2
FIDPIDInj
Vent HCV
MScryompr
sniffport
GC ovenpre-column analytical
Optimized for trace aroma/odor analysis
Permits: Heartcutting, cryofocusing, and backflushing to ferret out aroma components hidden in non-aroma components.
Columns of different polarity
Open Split
Interface
AromaTraxModel 2100 Multidimensional GC/O-MS
MDGC MethodologySome portions of separations may not resolve well
due to complexity or some portions may mask
important odor components. Dairy Grade Polyethylene Headspace
Heart-cut Separations
Intense off-odor
Heart Cutting:
-Permits better resolution of trace or masked components..
- To resolve all components in a complex mixture by passing a portion of column effluent to a second column using flow switching
-Backflushing the uninteresting volatiles to vent, permitting the heart cut portion to resolve by itself in second column.
Back Flushing
Getting rid of uninteresting volatiles
No bake out
And
Cryotrapping
Reduce diffusional broadening.
Focus sample
Heartcut Region
ANALYTICAL Column - PID of Heartcut
PRECOLUMN-FID
2-AP -Popcorn aroma in rice
MDGC Separation of 2-AP
Rice Volatiles Continued - “Needle in the Haystack”
MDGC Heartcut permits increase resolution for the MSD and other Detectors
What’s Smelly?What’s Smelly?
Over 100 different aroma chemicals were identified from the samples.
d- limonene (terpene / essential oil family) was a prominent chemical in all of the tested samples.
Toluene (aromatic hydrocarbon) was also found in the aroma profile.
Material Selection
Barrier Name Polymer Family
OPP Poly(olefins)
PVDC Copolymer Poly(vinyls)
OPP with barrier coating Multi-layered Structure
Nylon-6 Poly(amides)
PET Poly(esters)
Odor Barrier Study
Analysis Temp: 23C Using the saturated vapor pressure of limonene and
toluene at 23C
Toluene: (25.59mmHg); Limonene: (1.84 mmHg)
Odor Barrier Study
Odor Barrier Study
0.0000
0.0020
0.0040
0.0060
0.0080
0.0100
0.0120
0.0140
0 10 20 30 40 50 60 70 80
Days
g*m
m/(
m2
*day
)
Example of Organic Transmission Rate Data
Odor Barrier Results (d- Limonene)
Material Name
Limonene-TRThickness
Normalized(g*mil)/(m2-day)
Ranking
(1 = best, 5 = worst)
OPP 5.84 5
PVDC Copolymer 0.038 3
OPP with barrier coating
1.67 4
Nylon-6 8.2 x 10-5 1
PET 1.4 x 10-4 2
Odor Barrier Results (Toluene)
Material Name
Toluene -TRThickness
Normalized(g*mil)/(m2-day)
Ranking
(1 = best, 5 = worst)
OPP 750 5
PVDC Copolymer 162 4*
OPP with barrier coating
21 3*
Nylon-6 3.8 x 10-4 2
PET 3.6 x 10-4 1
Oxygen Barrier Study
Analysis Temp: 23C Test Gas:
100% O2 (dry) Carrier Gas:
98%N2 / 2%H2 (dry) Instrument:
MOCON Oxtran® 2/21 Methodology:
ASTM D-3985
Oxygen Barrier Study
Oxygen Barrier Study
Example of Oxygen Transmission Rate Data
Oxygen Barrier Results
Material Name
Oxygen TransmissionThickness
Normalized(cc*mil)/(m2-day)
Ranking
(1 = best, 5 = worst)
OPP 1200 5
PVDC Copolymer 28 2
OPP with barrier coating
2.0 1
Nylon-6 42 3
PET 56 4
So, how do they compare?
Odor Barrier / Oxygen Barrier Comparison
Odor Barrier / Oxygen Barrier Comparison
Barrier Comparison
0.00001
0.0001
0.001
0.01
0.1
1
10
100
1000
OPP PVDC PET Nylon-6 PVDC/OPP
Sample Name
Org
anic
Per
mea
tion
g*m
il/(m
2-da
y)
1
10
100
1000
10000
Oxy
gen
Perm
eatio
n cc
/(m2*
day)
Toluene-TR
Limonene-TR
OTR
Odor Barrier / Oxygen Barrier Comparison
Material Name
Transmission Rate(Normalized)
d – Limonene(gm*mil)/(m2-day)
Toluene (gm*mil)/(m2-day)
Oxygen(cc*mil)/(m2-day)
OPP 5.84 750 1200
PVDC Copolymer 0.038 162 28
OPP with barrier coating
1.67 21 2.0
Nylon-6 8.2 x 10-5 3.8 x 10-4 42
PET 1.4 x 10-4 3.6 x 10-4 56
Odor Barrier / Oxygen Barrier Comparison
Material Name
Transmission Rate(Normalized)
d – Limonene(gm*mil)/(m2-day)
Toluene (gm*mil)/(m2-day)
Oxygen(cc*mil)/(m2-day)
OPP 5.84 750 1200
PVDC Copolymer 0.038 162 28
OPP with barrier coating
1.67 21 2.0
Nylon-6 8.2 x 10-5 3.8 x 10-4 42
PET 1.4 x 10-4 3.6 x 10-4 56
Odor Barrier / Oxygen Barrier Comparison
Material Name
Material Ranking (1 = best, 5 = worst)
d - Limonene Toluene Oxygen
OPP 5 5 5
PVDC Copolymer 3 4 2
OPP with barrier coating
4 3 1
Nylon-6 1 2 3
PET 2 1 4
ConclusionsConclusions
Oxygen transmission rate testing of different polymer families could not accurately predict or rank the organic barrier properties of the same films.
Material Name
Transmission Rate(Normalized)
d – Limonene(gm*mil)/(m2-day)
Toluene (gm*mil)/(m2-day)
Oxygen(cc*mil)/(m2-day)
PVDC Copolymer 0.038 162 28
OPP with barrier coating
1.67 21 2.0
Nylon-6 8.2 x 10-5 3.8 x 10-4 42
PET 1.4 x 10-4 3.6 x 10-4 56
Conclusions
There is no “universal” conversion factor from oxygen results to organic results
Material Name
Organic to Oxygen Ratio
d – Limonene TR Oxygen TR
Toluene TR Oxygen TR
OPP 0.0048 0.63
PVDC Copolymer 0.0014 5.79
OPP w/ coating 0.84 10.5
Nylon-6 1.95 x 10-6 9.05 x 10-6
PET 2.50 x 10-6 6.4 x 10-6
Average Ratio 0.17 3.4
Standard Deviation 0.37 4.7
Conclusions
For the same polymer material, different organics can yield different and unpredictable results. This is largely due to polymer / permeant interactions.
Material Name d – Limonene(gm*mil)/(m2-day)
Toluene (gm*mil)/(m2-day)
PVDC Copolymer 0.038 162
OPP with barrier coating
1.67 21
Conclusions
In most cases, the best way to determine whether a material is a good organic (aroma or odor) barrier, is to:
First : Determine which organics are the key players.
Second: Test the material with the proper permeant.
Even though oxygen transmission testing was a poor tool for ranking the overall organic barrier for differing materials, it may prove meaningful to use an oxygen / aroma correlation when comparing barrier properties of like polymers of different thickness, grades or added coatings.
Recommendation for a Future Study
Thank you!Thank you!
Questions, please!
Please join us next month…
Introduction to Scientific Instrument IQ/OQ/PQ Validations:
Wednesday, July 9, 2008
10 am Central
top related