Leaching of radio-oxidized poly(ester urethane) water-soluble molecules characterization

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Leaching of radio-oxidized poly(ester urethane)

water-soluble molecules characterization

E. Fromentin, M. Pielawski, D. Lebeau, S. Esnouf, M. Ferry, F. Cochin, N. Caron, S. Legand

To cite this version:

E. Fromentin, M. Pielawski, D. Lebeau, S. Esnouf, M. Ferry, et al.. Leaching of radio-oxidized poly(ester urethane) water-soluble molecules characterization. 13th Tihany Symposium on Radiation Chemistry, Aug 2015, Balatonalmadi, Hungary. �cea-02489486�

Leaching of radio-oxidized

poly(ester urethane):

water-soluble molecules

characterization

24 FÉVRIER 2020 CEA | 10 AVRIL 2012| PAGE 1 E. Fromentin1_{*, M.Pielawski}1_{, D.Lebeau}1_{, S. Esnouf}1_{, M.Ferry}1_, F.Cochin2_{, N.Caron}3 _{and S. Legand}1

1_{CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette, France.}

2_{AREVA NC DOR/RDP, 1 place Jean Millier, F-92084 La Défense Cedex, France.} 3_{CEA, DEN, DPC, F-91191 Gif-sur-Yvette, France.}

13th Tihany Symposium on Radiation Chemistry 29th _August-3rd _{September 2015}

Long-term degradation (≈ 1,000 years): radiolysis and alkaline hydrolysis

Question: what is the effect of water-soluble products on the radionuclides mobility?

INTRODUCTION

24 FÉVRIER 2020 | PAGE 2

A repository disposal diagram:

500 m

Repository facility Geological layers

Polymers Radionuclides

Waste packages (intermediate level-long-lived)

Considered polymer

Poly(ester urethane) (PUR)

Used as glove for glove boxes

Composed of 3 segments issued from these molecules

hard segment extender soft segment

+ 8.9% inorganic fillers

+1,8% cross linking agents

+0,4% pigments

INTRODUCTION

| PAGE 3 1,4-butandiol

4,4’-methylene diphenyl diisocyanate _{poly(1,4-butylene adipate)}

H O O O O O H n

25.5%

_w

63.4%

_w

Objectives

Characterizing and quantifying water-soluble molecules created by the alkaline hydrolysis of the non-irradiated and irradiated PUR at different doses

Understanding the degradation mechanisms PUR under radiolysis

Irradiated PUR under hydrolysis

Identifying the products than can complex with the radionuclides

Being able to model the complexant release kinetics

INTRODUCTION

Objectives

Characterizing and quantifying water-soluble molecules created by the alkaline hydrolysis of the non-irradiated and irradiated PUR at different doses

Understanding the degradation mechanisms PUR under radiolysis

Irradiated PUR under hydrolysis

Identifying the products than can complex with the radionuclides

Being able to model the complexant release kinetics

INTRODUCTION

MATERIALS

A two-step preparation

1st _{step: PUR is irradiated under air using} g rays by IONISOS (60_{Co source), dose}

rate: ~ 0.7 kGy.h-1_{, doses: 4 MGy (~ 8 months irradiation) and 10 MGy}

(~ 20 months irradiation)

2nd _{step: non-irradiated and irradiated PUR is then hydrolyzed and the pH is}

maintained constant = leaching

24 FÉVRIER 2020 | PAGE 6 pure water or cementitious water 10 mL polymer 1g inert atmosphere 1 month at 60°C with pH maintained constant (pH 13) Filtrations Cementitious water composition:

0.25 mol/L NaOH, 10-3_mol/L Ca(OH)2and 41.10-3mol/L NaCl

Leachate Total Organic Carbon analysis TOC analyzer Targeted analyses of lowmolecular weight molecules (< 2 000 Da) Organic acids IC

Volatile and semi-volatile organic molecules GC-MS Other organic molecules LC-MS MS-MS Targeted analyses of highmolecular weight molecules Weight average molecular SEC

RESULTS AND DISCUSSION

Analytical approach

24 FÉVRIER 2020

Leachate Total Organic Carbon analysis TOC analyzer Targeted analyses of lowmolecular weight molecules (< 2 000 Da) Organic acids IC

Volatile and semi-volatile organic molecules GC-MS Other organic molecules LC-MS MS-MS Targeted analyses of highmolecular weight molecules Weight average molecular SEC

RESULTS AND DISCUSSION

Analytical approach

24 FÉVRIER 2020

Total Organic Carbon = TOC, ionic chromatography → carboxylic acids quantification Material balances obtained for leachates in pure water:

Material balances obtained for leachates in cementitious water:

RESULTS AND DISCUSSION

TOC measurement + IC quantification

24 FÉVRIER 2020 | PAGE 9 acetic acid formic acid glutaric+succinic acids malonic acid adipic acid oxalic acid unknown 0 MGy 4 MGy

There is a need to investigate the leachates by other analytical techniques.

10 MGy 4 MGy

0.26 mol C/kg of PUR

Origin of adipic acid : PUR soft segment

10 MGy

8.53 mol C/kg of PUR

17.7 mol C/kg of PUR

20.2 mol C/kg of PUR

26.1 mol C/kg of PUR _{29.5 mol C/kg of PUR}

Molecules detected in the 10 MGy irradiated PUR leachate in pure water

Some molecules are directly identifiable in the polymer formula :

Other molecules are due to chain scission or chain ends radio-oxidation, or due to ester groups hydrolysis and rearrangements.

RESULTS AND DISCUSSION

Gas chromatography-mass spectrometry

24 FÉVRIER 2020 | PAGE 10

pentanoic acid _{butanoic acid propionic acid} 1,4-butanediol

4,4′-diaminodiphenylmethane

soft segment

extender

hard segment

ethylene glycol 1,3-propanediol 3-hydroxytetrahydrofurane 2-hydroxytetrahydrofuran OH O 1-hydroxypropan-2-one 1,2-butanediol 2-hexanol

alcohols

cyclobutyl hexanoate

4-hydroxybutylacrylate _{dipropyl hexanedioate} 1,4-diacetoxybutane propyl propanoate

O O

propyl butanoate propyl 3-methylbutanoate diisopropyl adipate

linear esters

ethylene carbonate 1,6-dioxacyclododecan-7,12-dione gamma-butyrolactone 5-hydroxymethyldihydrofuran-2-one delta-valerolactone gamma-valerolactone

lactones

Molecules detected in the 10 MGy irradiated PUR leachate in pure water

Some molecules are directly identifiable in the polymer formula :

Other molecules are due to chain scission or chain ends radio-oxidation, or due to ester groups hydrolysis and rearrangements.

RESULTS AND DISCUSSION

Gas chromatography-mass spectrometry

24 FÉVRIER 2020 | PAGE 11

pentanoic acid _{butanoic acid propionic acid} 1,4-butanediol

4,4′-diaminodiphenylmethane

soft segment

extender

hard segment

ethylene glycol 1,3-propanediol 3-hydroxytetrahydrofurane 2-hydroxytetrahydrofuran OH O 1-hydroxypropan-2-one 1,2-butanediol 2-hexanol

alcohols

cyclobutyl hexanoate

4-hydroxybutylacrylate _{dipropyl hexanedioate} 1,4-diacetoxybutane propyl propanoate

O O

propyl butanoate propyl 3-methylbutanoate diisopropyl adipate

linear esters

ethylene carbonate 1,6-dioxacyclododecan-7,12-dione gamma-butyrolactone 5-hydroxymethyldihydrofuran-2-one delta-valerolactone gamma-valerolactone

lactones

RESULTS AND DISCUSSION

Gas chromatography-mass spectrometry

An example of a degradation mechanism:

24 FÉVRIER 2020 | PAGE 12 C C H₂ C H₂ C H₂ C H₂ C O O O O R R ° C H₂ C H₂ C H₂ C H₂ C O O R C H₃ C H₂ C H₂ C H₂ C O O R C H₂ C H₂ C H₂ C H₂ C O O R ° O O O O + O₂ C H₂ C H₂ O H - H₂O C H₂ C H₂ O H O + O₂ C H₃ C H₂ C H₂ C H₂ C O O H O R C O C H₂ C H₂ C H₂ C H₂ ° O O R C O C H₂ C H₂ C H₂ C H₂ O H C O O H C H₂ C H₂ C H₂ C H₂ O H g

g

+ P O O ° + P O ° + H ° + H ° h y d r o ly s is p e n t a n o i c a c i d r in g - c lo s u r e d e l t a - v a l e r o l a c t o n e h y d r o ly s is

CONCLUSION

Goals of the study:

Characterizing and quantifying water-soluble molecules created by the alkaline hydrolysis of the non irradiated and irradiated PUR

Understanding the degradation mechanisms • PUR under radiolysis

• Irradiated PUR under hydrolysis

Ionic chromatography + TOC analyzer = material balance,

but

the material balances

are not complete.

Solution

→

developing other analytical techniques such as:

Gas chromatography coupled with mass spectrometry

CONCLUSION

Results:

New molecules detected: the knowledge of released molecules is improved Identification of the molecules origin

• Fragments of the polymer formula

• Compounds obtained by chain scission, chain ends oxidation, ester groups hydrolysis or/and rearrangements

=> Better understanding of the mechanisms of irradiation and of leaching

Perspectives:

Quantifying the molecules detected by GC-MS

Identifying the molecules than can complex with the radionuclides Following the complexant release kinetics

=> Irradiated PURm hydrolysis mechanisms to be proposed

Nuclear Energy Division

Departement of Physical Chemistry Laboratory of Radiolysis and Organic Matter

French Alternative Energies and Atomic Energy Commission (CEA)

Centre de Saclay| 91191 Gif-sur-Yvette Cedex

T. +33 1 69 08 27 62 |elodie.fromentin@cea.fr

Etablissement public à caractère industriel et commercial |R.C.S Paris B 775 685 019

24 FÉVRIER 2020 | PAGE 15

CEA | 10 AVRIL 2012

ACKNOWLEDGMENT

This work has been financed by AREVA. Thanks to S.Rouif (IONISOS) for her helpful collaboration during irradiation.

Thanks to V. Dauvois, E. Zerki, M. Tabarant, S.Sandirin, J.L. Roujou, A.Turban, D. Durand for their ideas and technical help.

Thank you for your

attention.

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