VERSATILE WASTE PLASTIC IDENTIFIERBASED ON RAMAN SPECTROSCOPY FOR MATERIAL RECYCLE
A. Tsuchida1, Y. Tsuchida1, T. Yoshida1, K. Arikata1 and H.Kawazumi2*
1 Saimu Corporation, Iizuka, Japan
2 School of Industrial Technology, Kinki University, Iizuka, Japane-mail: kawazumi@fuk.kindai.ac.jp

Abstract
Various techniques have been introduced for plastic recycling, but no versatile techniques is available at the moment. We
have been approaching this problem using Raman Spectroscopy. It is a technique of molecular structure analysis, similar
to IR absorption. The Raman spectroscopy is not affected from water so we could adapt it to wet plastics, and its sharp
peaks make easy to gain signal-to-noise ratio which enable us definite identification unlike NIR technique. Those featuresof Raman spectroscopy works well when it comes to industrial uses. On this paper, we introduce the portable plastic
identifier we have developed and demonstrate applications to wet surface conditions, identifications of similar or black
plastics and detections of RoHS restricted substance and additives.

Keywords: Plastic recycling, Material Recycling, Raman spectroscopy, Black-color plastics, RoHS restricted substances

1. Introduction
Raman spectroscopy apparatus is known to have highprice until recently, therefore, this technology was notavailable for industrial field. However, The rapid
development in the telecommunication system is making
the price of optical components and laser diode lower.
As the equipment price decrease, the industrial use ofthis technique also begins to take place. Our groupapplies this technique for plastic recycling, and we aresuccessfully demonstrated the accuracy andperformance in the material recycle of shredder dustcoming from Japanese household electric home
appliance recycling plant [1,2].
In the ordinary plastic recycling plant, identification ofplastics is done by touched feeling and observing theframe when it ignite with lighter for cigarette. This
technique is simple and easy to use, on the other hand,
you need experience, and the accuracy is not good evenwith experienced person. This is because, similarmaterial is commonly existed and additives in plastics
make it harder to analyze. In the material recycle, eventhe similar materials causes problem. Therefore, weneed molecular structural analysis in the plastic
recycling.
As the tool used in the industrial environment, it
should have following feature;
1. easy to use, and quick response,
2. able to work with any color, water or dust on thesurface,
4. able to work with bended or scrunched surface
condition,
5. able to detect bromine compound restricted by RoHS.

On this paper we demonstrate possibility of Raman
spectroscopy in industrial plastic recycling by using
newly-developed plastic identifier.

2. Materials and Methods
In this experiment, we use portable Raman plasticidentifier developed by Saimu Corporation. Real waste
plastics as test samples are collected from a local plastic
recycling plant.
(a)

(b)

Figure 1: (a) Portable Raman Plastic Identifier, (b)software which displays a measured Raman spectrum
and determined material name.

3. Results and Discussion
In this section, used PET Bottle is measured withRaman Plastic Identifier. Then, PS, HIPS and AS isscanned as for example of similar plastics. And, DeBDE
and TBBA mixed with PP are measured to show thedetection of RoHS restricted substance. At last,
determination of black waste plastics is demonstrated.

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013

500

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Raman Shift / cm-1
Fgure 2: Raman spectrum of wet PET bottle.

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Figure 2 shows a Raman spectrum of a wet PETbottle. The Plastic Identifier display on the softwareshows the material name is PET resulting from the peakanalysis in figure 2. It is done by seeking at unique peakat 1600cm-1 and 1700cm-1. Peak at 1600cm-1 is comingfrom Benzene structure and peak at 1700cm-1 is thesignal coming from ester bonding.

Raman
RamanIntensity
Intensity/ /A.U.
A.U.

Raman Intensity / A.U.

detect RoHS restricted substances and other additives
as well.

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Raman Shift / cm-1
Figure 5: Identification of black plastic.

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Figure 5 shows a Raman spectrum of a piece of blackplastic. The software shows the material is HIPS. The
pointing peaks could be used for the identification ofblack plastic.

4. Conclusions
Raman Intensity / A.U.

We successfully demonstrate the versatile applicationin the industrial plastic recycling by using the Ramanidentifier developed. It is commercially available at thistime.

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Raman Shift / cm-1
Figure 3: Identification of similar type of plastics.
Figure 3 shows Raman spectra of general purpose
polystyrene (GPPS), high impact polystyrene(HIPS), andacrylonitrile polystyrene (AS). It is possible to differentiate
by looking at peak coming from butadiene andacrylonitrile. It also possible to estimate component
fractions in composite materials by further analysis.

Raman Intensity / A.U.

References

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Raman Shift / cm-1
Figure 4: Identification of bromine compounds on PP
Figure 4 shows Raman spectra of polypropylene (PP)and PP with deca-brominated diphenyl ethers (DeBDE),
PP with tetrabromobisphenol A (TBBA). By seeking thepeak originated in added substance. It is possible to[1] H.Kawazumi, A.Tsuchida, K.Arikata, Y.Tsuchida, H.
Hasuo and T.Oosaki. The abstract from The 6thInternational Symposium on Feedstock Recycling ofPolymeric Materials (ISFR2011) in Toledo, Spain, 5-7
October, 2011[2] A. Tsuchida, T. Yoshida, Y. Tsuchida, H. Kawazumi,“Identification and degradation estimation of waste
plastics using Raman spectroscopy”, Bunseki Kagaku,
61, 1027-1032 (2012).

Acknowledgment
Authors have had the financial support from The Ministryof Economy, Trade and Industry of Japan.

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013