Infrared Analysis of Carbon-Rich Polymers Using Cantilever Enhanced Photoacoustic Detector
Kaori Watanabe and Fumiko Hiwatashi
Systems Engineering Inc. www.systems-eng.co.jp info@systems-eng.co.jp
Introduction

Experiment

Carbon materials in industry

FT-IR: Bio-Rad FTS575C
PAS detector: GASERA PA301

Even emerging demands
Flexible, mobile and conductive

Mirror speed: 2.5 kHz (0.1581 cm s-1); Resolution: 4 cm-1; Gain: 0.1;

Can be used in displays and batteries

Accumulation: 32 or 256 scans

Spectroscopy of carbon-rich materials

SampleCarbon FEF1

PA intensity / arb. units

20304050

60

0

1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5

Carbon %08.8 16

23

These compound samples were supplied by Zeon Corporation

22833

37

Qualitative
up tp 25% C

2000

-1

1000
Photoacoustic / arb. units

Photoacoustic Spectroscopy (PAS)

2240
C≡N

2925
C–H

wavenumber / cm

2.0
1.5
1.0
0.5
0.0

3. Heat diffuses back to sample surface
4. Thermal expansion of surrounding gas detected• Depth-profiling

60 PHR

4000

253500

3000

2500

2000
-1
wavenumber / cm

975/2240
1440/2240
2925/22402020 PHR
10 PHR
3500

3000

4.

2500

2000
-1
wavenumber / cm

1500

1000

1500

1000

10More carbon on surface

5Large band like 975 cm-1 canbe observed even at 50% C

1.5

1.0

Quantitative peak hight

0.5

0975
1440
2240
2925

32 scans
256 scans

2.5

15even at > 50% C

0.0
01020
30% Carbon

4002040
60% Carbon

Conclusion
PAS detection limit of carbon-rich polymer has been investigated
Small or high-frequency band: Quantitative up tp 10% C• Versatile

Qualitative up tp 25% C» Irregular shaped, small, or opaque sample etc.
10500

2.0500Peak height

Peak height / arb. units• Non-destructive

70 PHR

Peak height ratio

PAS advantage• Highly sensitive

1710
C=O10 PHR

30 PHR

2.

*: PAS sampling depth ∝ ω−1/2

4020 PHR

50 PHR

4000

40100 PHR

60 PHR

2. Absorbed energy partially transformed into heat

3030 PHR

70 PHR

1.

20

2. UV irradiated (96 hr) NBR (256 scans)

975
C=C–H

1440
C–H

20
30% Carbon

1050 PHR
40 PHR

40 PHR(non-radiating relaxation)

10Oxidization

100 PHR

Photoacoustic spectroscopy

3.

01. PAS spectra of carbon-containing NBR (256 scans)

S/N = 133000049

Produced by Zeon Corporation

Conventioanl 1scan

4000

40Results and Discussion

Sample: PE

S/N = 137

PAS with the cantilever detector» THz, IR, NIR, UV-Vis etc.

1070 100

Antioxidant Nocrac MBZ» 1/100 accumulation time!

• Investigation of the detection limit of

101.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5• Ten times more sensitive than microphone
PA301 1scan

00

Novel PAS detector (GASERA; booth 555)
• Cantilever and laser interferometer based detector100 100 100 100 100 100 100 100 100

Antioxidant Nocrac CD

× Longer accumulation time due to low sensitivity of the detector

1. Sample absorbs incident lightup tp 10% C

Peak height ratio• PAS: ○ Less influenced by absorption and refractive index

carbon-containing NBR

Quantitative

15

5NBR Nipol® DN2022• Reflection: Distorted due to high refractive index• Quantitative study on PAS spectra of1

Small or high-frequency* band:0• Transmisson: Saturated due to large absorption

This study

Peak height ratio• Electrochemical stability

20Measuremente.g. Carbon-filled polymer electrodeLarge or low-frequency* band: Quantitative even at 50% C

975/2240
1440/2240
2925/2240

Photoacoustic / arb. units• High chemical stability

25

Peak height ratio

have long been used for...

Peak height ratio

2030% Carbon40

Large or low-frequency band: Quantitative up to 50% C

80100