Ethyl 2-cyanoacrylate

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

Study period:

September - October 2019

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 details the results of investigations aimed at studying the polymerization of cyanoacrylate monomers in water/aqueous systems and on glass surfaces. Investigations involved the use of calorimetry techniques to measure bulk polymerization exotherms of ethyl and ally) cyanoacrylate monomers 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 polymerization occurring within seconds to minutes. The rapid polymerization in aqueous systems/glass surfaces is strongly supported by attenuated total reflectance (ATR) FT-IR studies. ATR FT-IR was used to observe the rapid polymerization of a droplet of ethyl cyanoacrylate monomer that had been exposed to a fine spray of water. The extent of polymerization 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 fonnation and increase in intensity of the C-CH2- stretch absorption band at 1250 cm-1
Sequential FT-IR scans of the film approximately every 15-30 seconds over a 10-minute period showed rapid polymerization of the ECA monomer droplet within seconds of exposure to water and complete polymerization within 10 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 polymerization of cyanoacrylate monomers in aqueous solutions and on glass surfaces. Both Ethyl CA (ECA) and Ally! CA (ACA) undergo instantaneous rapid polymerization on mixing with equal volumes of water (de-ionised and tap water) within seconds to minutes.
ECA polymerizes more rapidly relative to ACA. The difference in monomer reactivity can be attributed to the higher hydrophobicity of ACA which makes ACA intrinsically less soluble in water resulting in a tendency to fonn larger droP,let sizes when mixed with water. The larger droplet size results in a lower interfacial surface area to volume ratio compared to ECA, with a lower rate of polymerization due to the reduced water-monomer interfacial surface area. There are also differences in the weak acid contents of the ECA and ACA monomers resulting in a retarded ACA polymerization response. Both monomers undergo very rapid polymerization on glass beads within seconds.
ATR FT-IR spectroscopy was also used to monitor real-time polymerization of a droplet of ECA monomer 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 -Cfostretch absorption band at 1250 cm·1 indicate rapid polymerization of a droplet of CA monomer within minutes of being exposed to water.

Executive summary:

Calorimetric techniques were used to monitor the bulk polymerization of cyanoacrylate monomers in aqueous solutions and on glass surfaces. Both Ethyl CA (ECA) and Allyl CA (ACA) undergo instantaneous rapid polymerization on mixing with equal volumes of water (de-ionised and tap water) within seconds to minutes.

ECA polymerizes more rapidly relative to ACA. The difference in monomer reactivity can be attributed to the higher hydrophobicity of ACA which makes ACA intrinsically less soluble in water resulting in a tendency to fonn larger droP,let sizes when mixed with water. The larger droplet size results in a lower interfacial surface area to volume ratio compared to ECA, with a lower rate of polymerization due to the reduced water-monomer interfacial surface area. There are also differences in the weak acid contents of the ECA and ACA monomers resulting in a retarded ACA polymerization response. Both monomers undergo very rapid polymerization on glass beads within seconds.

ATR FT-IR spectroscopy was also used to monitor real-time polymerization of a droplet of ECA monomer 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 -Cfostretch absorption band at 1250 cm·1 indicate rapid polymerization of a droplet of CA monomer within minutes of being exposed to water.