2-Propenoic acid, homopolymer

Explosiveness

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

explosive properties of explosives

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

UN Manual of Tests and Criteria: Part I: Classification procedures, test methods and criteria relating to explosives of Class 1

Deviations:

no

GLP compliance:

no

Specific details on test material used for the study:

- Analytical purity: >=99%
- Purity test date: 16 May 2017
- Lot/batch No.: BA6J16508
- Expiration date of the lot/batch: 16 November 2018
- Appearance: Colourless limpid liquid
- Storage: In darkness at room temperature

Key result

Test series:

UN Test series 2

Method:

UN Test 2 (a): UN gap test

Parameter:

fragmented length (cm)

Value:

0

Result:

result is considered "-" (negative)

Remarks:

The test item is not sensitive to a detonative shock

Key result

Test series:

UN Test series 2

Method:

UN Test 2 (b): Koenen test

Parameter:

limiting diameter (mm)

Result:

negative, no violent effect on heating under confinement

Remarks:

The test item is not sensitive to intense heating under high confinement

Remarks on result:

not determinable

Remarks:

At the smallest diameter of 1.0 mm, the tube did not rupture

Key result

Test series:

UN Test series 2

Method:

UN Test 2 (c) (i): Time/pressure test

Parameter:

other: pressure rise time (ms)

Result:

result is considered "-" (negative)

Remarks:

The test item is not sensitive to ignition under confinement

Remarks on result:

not determinable

Remarks:

The lower threshold of 6.9 bar was not achieved

Test 2(a): UN GAP TEST (detonation)

The results are shown in Table 1.

Table 1. Results of the detonation test

Test	Apparent density [kg/m³]	Fragmentation length [mm]	Result
1	1286	0	no result
2	1286	0	no result

On the basis of the test results and in accordance with the criteria specified in the UN Manual of Tests and Criteria, it is concluded that the investigated sample is not sensitive to a detonative shock under the conditions of UN test series 2. When testing according to test series 1, the test is carried out in a different set-up. No gap is present and the booster charge is placed directly against the tube. Thus, the shock is transferred to the substance without attenuation. The substance is considered to be able to detonate if the tube is fragmented completely. Because in the series 2 test the substance did not respond at all, it is concluded that in a series 1 test the substance will not be able to cause complete fragmentation of the tube. This is supported by the decomposition energy of the substance as reported by the assignor, which is 915 J/g. Substances having such low decomposition energy are not able to detonate.

Test 2(b): KOENEN TEST (heating under confinement)

At the smallest diameter of 1.0 mm, the tube did not rupture. On the basis of the test results and in accordance with the criteria specified in the UN Manual of Tests and Criteria, it is concluded that the investigated sample is not sensitive to intense heating under high confinement in the sense of the criteria of UN test series 2. When testing according to test series 1, the same test is carried out but the result is evaluated against a more stringent criterion (maximum acceptable limiting diameter <1.0 mm). The above test result also fulfils this criterion. Hence, it is concluded that the investigated sample is not sensitive to intense heating under high confinement in the sense of the criteria of UN test series 1.

Test 2(c)(i): TIME/PRESSURE TEST (ignition under confinement)

The results are shown in Table 2.

Table 2. Results of the time/pressure test

Test	Maximum pressure [bar]	Time taken for the pressure to rise from 6.9 bar to 20.7 bar [ms]
1	2.00	-
2	2.08	-
3	4.02	-

In none of the tests, the lower threshold of 6.9 bar was achieved. On the basis of the test results and in accordance with the criteria specified in the UN Manual of Tests and Criteria, it is concluded that the investigated sample is not sensitive to ignition under confinement in the sense of the criteria of UN test series 2 and, hence, is not capable of propagating a deflagration. When testing according to test series 1, the same test is carried out but the result is evaluated against a more stringent criterion (maximum acceptable pressure less than 20.7 bar). The above test result also fulfils this criterion. Hence, it is concluded that the investigated sample is not sensitive to ignition under confinement in the sense of the criteria of UN test series 1 and, hence, is not capable of propagating a deflagration.

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the results of the study and according to the criteria laid down in the UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria, sixth revised edition, it is concluded that the test item has no explosive properties and, hence, needs not to be classified as an explosive substance.

Executive summary:

The explosive properties of the REACH substance were investigated in a non-GLP study performed according to the test methods described in the UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria, sixth revised edition. Based on the results of the tests performed (UN test series 2: UN gap test, Koenen test and time/pressure test), it was concluded that the test item had no explosive properties and, hence, needs not to be classified as an explosive substance.

Reference 2

Endpoint:

explosive properties of explosives

Type of information:

other: statement

Adequacy of study:

other information

Study period:

From 2016-08-24 to 2017-05-09

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline required

Principles of method if other than guideline:

The aim of the study was to collect data on the test item in order to determine if experimental studies relative to explosive properties (UN Test series 1 to 3) and oxidising properties (UN Test O.2) are required. The criteria of classification and labelling used in this study are in agreement with Regulation (EC) No. 1272/2008 (CLP).

GLP compliance:

no

Specific details on test material used for the study:

- Composition of test material: 2-carboxyethyl acrylate oligomers (= homopolymers of acrylic acid + 2-carboxyethyl acrylate) and acrylic acid
- Analytical purity: >=99%
- Purity test date: 24 August 2016
- Lot/batch No.: BA5H22021
- Expiration date of the lot/batch: 24 August 2017
- Appearance: Colourless limpid liquid
- Storage: In darkness at room temperature

According to literature, acrylic acid acid has a potential for explosive properties (low explosion limits). Acrylic acid homopolymer and 2-carboxyethyl acrylate are not expected to present explosive properties (no chemical groups associated with explosive properties); only dust explosion hazard was identified in literature data for acrylic acid homopolymer, which is not relevant since the test item is formulated as an oily liquid. In a separate study (cf. background material), a Differential Scanning Calorimetry analysis was performed on the test item showing an exothermic reaction with an enthalpy of 914.90 J/g with an onset of exothermic decomposition below 500°C (335°C). According to Regulation (EC) No.1272/2008 and although the test item does not contain structural alerts, the test item may have a potential for explosive properties; explosive properties test should be conducted to conclude.

Interpretation of results:

study cannot be used for classification

Conclusions:

According to Regulation (EC) No.1272/2008 and although the test item does not contain structural alerts, the test item may have a potential for explosive properties; explosive properties test should be conducted to conclude.

Executive summary:

The test item is composed of homopolymers of acrylic acid, dimers of acrylic acid (2-carboxyethyl acrylate) and unreacted monomers (acrylic acid). According to literature, acrylic acid has a potential for explosive properties (low explosion limits). Acrylic acid homopolymer and 2-carboxyethyl acrylate are not expected to present explosive properties (no chemical groups associated with explosive properties); only dust explosion hazard was identified in literature data for acrylic acid homopolymer, which is not relevant since the test item is formulated as an oily liquid. In a separate study (cf. background material), a Differential Scanning Calorimetry analysis was performed on the test item showing an exothermic reaction with an enthalpy of 914.90 J/g with an onset of exothermic decomposition below 500°C (335°C). According to Regulation (EC) No.1272/2008 and although the test item does not contain structural alerts, the test item may have a potential for explosive properties; explosive properties test should be conducted to conclude.

Description of key information

The REACH substance is composed of homopolymers of acrylic acid, dimers of acrylic acid (2-carboxyethyl acrylate) and unreacted monomers (acrylic acid). According to literature, acrylic acid has a potential for explosive properties (low explosion limits). Acrylic acid homopolymer and 2-carboxyethyl acrylate are not expected to present explosive properties (no chemical groups associated with explosive properties); only dust explosion hazard was identified in literature data for acrylic acid homopolymer, which is not relevant since the REACH substance is formulated as an oily liquid. In a separate study, a Differential Scanning Calorimetry analysis was performed on the REACH substance showing an exothermic reaction with an enthalpy of 914.90 J/g with an onset of exothermic decomposition below 500°C (335°C). According to Regulation (EC) No.1272/2008 and although the REACH substance does not contain structural alerts, it may have a potential for explosive properties. The explosive properties of the REACH substance were therefore investigated in a non-GLP study performed according to the test methods described in the UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria, sixth revised edition. Based on the results of the tests performed (UN test series 2: UN gap test, Koenen test and time/pressure test), it was concluded that the REACH substance had no explosive properties and, hence, needs not to be classified as an explosive substance.

Key value for chemical safety assessment

Explosiveness:

non explosive

Additional information

The explosive properties of the test item were investigated in a non-GLP study performed in accordance with standard methods (Mak, 2017), without deviations; that experimental study is considered as reliable (Klimisch 1) and was selected as a key study for the endpoint.

Justification for classification or non-classification

The explosive properties of the REACH substance were first investigated based on a non-GLP literature review of the explosive properties of the constituents of the substance (Demangel, 2017). As this review pointed out that the substance may have a potential for explosive properties, the latter were further investigated in an experimental non-GLP study performed in accordance with standard methods (Mak, 2017). Based on the results of the tests performed (UN test series 2: UN gap test, Koenen test and time/pressure test), it was concluded that the test item had no explosive properties and, hence, needs not to be classified as an explosive substance.