REGULATORY & COMPLIANCE
Polymer solely a precursor handled like an intermediate under SCC to produce other polymers or articles ?
Polymer precursor yes no Polymer a polyester made from monomers on EU list ? no Polymer fluorinated ?
Polymer is non-PRR no Polymer meeting cationic criterion C1 ? no Polymer meeting MW criterion MW1 , MW2 or MW3 ? no Polymer classified in any of the 12 classes in Wood report ? no Polymer having reactive functional group of concern ( RFG1 )? no Polymer surface active ? (< 45 mN / m ) no Polymer suspected to degrade to substance ( s ) of concern ? no yes
yes
yes
yes
yes
yes
yes
Polymer Requiring Registration
Polymer is non-PRR
Based on information notified to ECHA or any additional evidence , MS can initiate Sev if they believe a polymer is of concern
Figure 1 – Decision tree for PRR classification handled under ‘ adequate control ’ would benefit from limited registration requirements , analogous to isolated on-site or transported intermediates under REACH Articles 17 or 18 .
A polyester that is made only from monomers on a specific EU list that will be published in a new annex , will be exempted . This will be based essentially on the ( rather short ) Australian list , minus a few reactants that experts advised removing . 1 Polymers defined as PRRs include :
• All fluorinated polymers , regardless of whether the fluorine is attached to the carbon backbone or is part of a fluorinated side chain
• Cationic polymers and polymers that are reasonably expected to become cationic in a natural environment , such as cationic flocculants and quaternary amine
• Polymers meeting MW1 , MW2 and MW3 criteria , as defined above , requiring full , reduced and minimal datasets respectively : the latter two include those containing > 2 % oligomers with MW of < 500 Da or > 5 % oligomers with MW of < 1,000 Da
• Surfactants with a surface tension < 45 mN / m
• Polymers that are designed , or can be expected , to substantially degrade , decompose or depolymerise into substances
having one or more of the hazard classifications listed in Table 2 – discussions are still ongoing about some definitions here Polymers classified as hazardous in any of the 12 classes in the Wood report ( Table 2 ) are also PRRs . It is not certain whether serious eye damage or skin corrosion and being hazardous for the ozone layer will be included , as they were not mentioned in Katrin Schütte ’ s presentation .
In addition , new hazard classes are currently under adoption , i . e endocrine disrupters ( ED ), persistent , bioaccumulative and toxic ( PBT ), very persistent , very bioaccumulative ( vPvB ), persistent , mobile and toxic ( PMT ) and very persistent , very mobile ( vPvM ). It is advisable to keep an eye on any potential change on any EU hazard classifications change .
Polymers having a reactive functional group of concern ( RFG 1 ) form one of the more complex elements , as there are three levels of concern to be considered together with the calculation of their FG equivalent weight ( FGEW ). The FGEW can be determined empirically , such as by titration or calculated by defined formulas depending on the specific position and polymer constitution .
Polymers containing only FGs with low concern are non-PRRs . Beyond that , it gets more complex .
Those containing FGs with moderate concern are PRRs if the FGEW is > 1,000 for the sum of all FGs . For those containing FGs with high concern the FGEW threshold is 5,000 . Those containing FGs with moderate and high concern are also PRRs if the FGEW is < 1,000 / single FG of moderate concern , < 5,000 / single FG of high concern or < 5,000 for the sum of all FGs .
Analytical options
To verify all these characteristics , certain information needs to be collected , notably the MW , the production process , and the identity and exact quantity of monomers . To measure the MW both of the polymers and oligomers , analytics have to be performed . There are two main methods that can be used
Gel permeation chromatography ( GPC ) is a type of size-exclusion chromatography , which separates analytes on the basis of size , typically in organic solvents . It has been the standard method for determining polymer MWs for decades .
What GPC actually measures is the molecular volume and shape function as defined by the intrinsic viscosity . This has certain limitations . If comparable standards are used , this relative data can be used to determine MWs to ± 5 % accuracy .
NOV / DEC 2023 SPECCHEMONLINE . COM
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