Enbucrilate

Additional information on environmental fate and behaviour

Administrative data

Endpoint:

additional information on environmental fate and behaviour

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Principles of method if other than guideline:

This report is a follow-on report to IRD 19-50 which investigated the reactivity of ethyl and allyl cyanoacrylate monomers towards water and on glass surfaces in support of Henkel Corporate Scientific Services’ submission dossier to ECHA for the REACH registration of cyanoacrylate monomers. This report details the results of investigations aimed at studying the speed of polymerisation of methyl, beta-methoxyethyl and n-butyl cyanoacrylate monomers in water/aqueous systems and on glass surfaces. Investigations involved the use of calorimetry techniques to measure bulk polymerisation exotherms of each cyanoacrylate monomer when exposed to water or to glass surfaces. The results demonstrate very high reactivity of cyanoacrylate monomers to both aqueous conditions and glass surfaces with very rapid polymerisation occurring within seconds to minutes. This is strongly supported by attenuated total reflectance (ATR) FT-IR studies. ATR FT-IR was used to observe the rapid polymerisation of a droplet of methyl/beta-methoxyethyl/n-butyl cyanoacrylate monomers that had been exposed to a fine spray of water. The degree of polymerisation was studied by monitoring the disappearance and change in intensity of the C=C stretch absorption band at 1287 cm-1 and the nitrile stretch absorption band at 2239 cm-1, along with concomitant formation and increase in intensity of the C-CH2- stretch absorption band at 1250 cm-1. Sequential FT-IR scans of the film approximately every 60 seconds over a 10-minute period showed rapid polymerisation of each CA monomer droplet within seconds of exposure to water and complete polymerisation within 30 minutes.

GLP compliance:

no

Test material

Test material information

Test material form:

liquid

Applicant's summary and conclusion

Conclusions:

Calorimetric techniques were used to monitor the bulk polymerisation of cyanoacrylate monomers in aqueous solutions and on glass surfaces. Each of Methyl CA (MeCA), beta-methoxyethyl CA (BMOECA) and n-butyl CA (n-BuCA) undergo instantaneous rapid polymerisation on mixing with equal volumes of water (de-ionised and tap water) within seconds to minutes. MeCA and BMOECA polymerise more rapidly in water relative to n-BuCA. The difference in monomer reactivity can be attributed to the higher hydrophobicity of n-BuCA which makes it intrinsically less soluble in water resulting in a tendency to form larger droplet sizes when mixed with water. The larger droplet size results in a lower interfacial surface area to volume ratio compared to MeCA and BMOECA, with a lower rate of polymerisation due to the reduced water-monomer interfacial surface area. All monomers undergo very rapid polymerisation on glass beads within seconds.
ATR FT-IR spectroscopy was also used to monitor real-time polymerisation of a droplet of each of MeCA, BMOECA and n-BuCA monomers when exposed to a fine mist of water droplets. Real-time monitoring for the disappearance of the C=C and -CN stretch absorption bands at 1287 cm-1 and 2239 cm-1 respectively, with concomitant formation of the -CH2- stretch absorption band at 1250 cm-1 indicate rapid polymerisation of a droplet of CA monomer within minutes of being exposed to water.

Executive summary:

Calorimetric techniques were used to monitor the bulk polymerisation of cyanoacrylate monomers in aqueous solutions and on glass surfaces. Each of Methyl CA (MeCA), beta-methoxyethyl CA (BMOECA) and n-butyl CA (n-BuCA) undergo instantaneous rapid polymerisation on mixing with equal volumes of water (de-ionised and tap water) within seconds to minutes. MeCA and BMOECA polymerise more rapidly in water relative to n-BuCA. The difference in monomer reactivity can be attributed to the higher hydrophobicity of n-BuCA which makes it intrinsically less soluble in water resulting in a tendency to form larger droplet sizes when mixed with water. The larger droplet size results in a lower interfacial surface area to volume ratio compared to MeCA and BMOECA, with a lower rate of polymerisation due to the reduced water-monomer interfacial surface area. All monomers undergo very rapid polymerisation on glass beads within seconds.

ATR FT-IR spectroscopy was also used to monitor real-time polymerisation of a droplet of each of MeCA, BMOECA and n-BuCA monomers when exposed to a fine mist of water droplets. Real-time monitoring for the disappearance of the C=C and -CN stretch absorption bands at 1287 cm-1 and 2239 cm-1 respectively, with concomitant formation of the -CH2- stretch absorption band at 1250 cm-1 indicate rapid polymerisation of a droplet of CA monomer within minutes of being exposed to water.