Plastics - Determination of the viscosity of polymers in dilute solution using capillary viscometers - Part 5: Thermoplastic polyester (TP) homopolymers and copolymers (ISO/DIS 1628-5:2026)

Comment end date 2026-08-25

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Project stage codes

1. Prioritetinių darbo temų pažymėjimas ir ekspertų skyrimas

2. Projektas

3. Viešoji apklausa

From 2026-06-26 till 2026-08-25

4. Closure of enquiry

5. Submission to Formal Vote

Organisation

CEN Europos standartizacijos komitetas

ICS

83.080.20 - Thermoplastic materials

Technical Committee

TK 68 Plastics

ForeignTC'S

CEN/TC 249

Number of comments

Comment start date

2026-06-26

Scope

This part of ISO 1628 specifies a method for the determination of the viscosity number (also referred to as "reduced viscosity") of dilute solutions of thermoplastic polyesters (TPs) in certain specified solvents. The method is applicable to poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly-(cyclohexylenedimethylene terephthalate) (PCT), and poly(ethylene naphthalate) (PEN), as well as to copolyesters and other polyesters, referred to in ISO 20028-1:2019, that are soluble in one of the specified solvents under the specified conditions. The viscosity number is determined by the general procedure specified in ISO 1628-1:2024, observing the particular conditions specified in this part of ISO 1628. The determination of the viscosity number of a thermoplastic polyester provides a measure of the relative molecular mass of the polymer.

Relations

Pakeis

prEN ISO 1628-5