Reach Polymer Status Analysis of Polyols

Friedhelm Gores, PSS Polymer Standards Service GmbH, Mainz, Germany.

Introduction

Polyols are alcohols with multiple hydroxyl groups. They are used for very different applications, such as, for example, in Feed and Food as sugar substitutes or in polymer chemistry as reactants to produce high quality products.

REACH (Registration, Evaluation and Authorization of Chemicals) is a European Union (EU) regulation for the production and use of chemical substances. Companies using polyols need a technical dossier to register under regulation EG No. 1907/2006.

Polymers are "special substances" in terms of REACH. However, companies have to proof that their products/educts ARE polymers. The preferred method to identify whether a substance falls under the definition of a polymer is gel permeation chromatography (GPC). Guidelines on the determination of the molecular weight distribution using GPC are available in the OECD TG118 (1996).

Analytical Conditions

The samples were dissolved in THF.

Results

A polymer molecule in the sense of REACH is a molecule that contains a sequence of at least 3 monomer units (M), covalently bound to at least one other monomer unit or reactant (initiator). This definition is equal with the so called (3M+1)-rule. Additional requirements are:

(a) Over 50 percent of the weight for that substance consists of polymer molecules.

(b) The amount of polymer molecules presenting the same molecular weight must be less than 50 weight percent of the substance.

Figure 1

To determine if the above stated requirements are true, a GPC/SEC experiment using high resolution columns is performed. Figure 1 shows the elugram of a Polyol showing separation into individual R-(M)_x peaks. The results for the detailed analysis are summarized in Table 1.

Table 1: Content and molar mass average report for a Polyol and comments to the REACH requirements.

Conclusion

The Polyol is a polymer in the context of REACH because:

• Less than 50 weight percent of the sample is below (3M+1), the sample consists mainly of polymer molecules with n >3. The (3M+1)-rule is met.

• None of the different constituents present has a concentration above 50 weight percent.

PSS Polymer Standards Service GmbH

In der Dalheimer Wiese 5, D-55120 Mainz, Germany

tel. +49 6131 96239 50 fax +49 6131 96239 11

E-mail: FGores@polymer.de Website: www.polymer.de