YY/T 1678-2019Test method for molecular weight averages and molecular weight distribution of polylactic acid and its copolymers for surgical implants (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

1 Scope

This standard specifies the determination of the average molecular weight (MW) and molecular weight distribution of soluble polylactic acid by high-performance size exclusion chromatography (HPSEC). Methods.

This standard applies to surgical implants, including poly (L-lactic acid) resin, which can be completely dissolved by chloroform (or other solvents).

(PLLA), poly (D-lactic acid) resin (PDLA), DL-type interpolymers in any ratio, and lactide (PLA) and lactide-glycolide copolymers Materials (PLGA).

Note 1. This standard is not an absolute method and requires the use of a commercially available narrow molecular weight distribution polystyrene standard material for calibration.

Note 2. Since the production and processing of polylactic acid products (especially irradiation sterilization) will affect the molecular weight and molecular weight distribution of the material itself, therefore When evaluating products, testing should be performed on the finished product.

2 Normative references

The following documents are essential for the application of this document. For dated references, only the dated version applies to this document. For undated references, the latest version (including all amendments) applies to this document.

GB/T 2035-2008 plastic terms and definitions

3 Terms and definitions

The terms and definitions defined in GB/T 2035-2008 and the following apply to this document.

4 Method summary

A sample of polylactic acid dissolved in a solvent was injected into a chromatographic column filled with a solid matrix, and the polymer molecules in the solution were separated in order. from At the beginning of the injection, the detector continuously monitors the elution time coming out of the column, and the polymer molecules flowing out of the column are separated according to size and The molecular weight of the concentration separation is detected and recorded. Through the calibration curve, the elution time can be converted into molecular weight, and various molecular weight parameters of the sample can be changed.