ISO 16152:2022

Overview

ISO 16152:2022 - Plastics - Determination of xylene‑soluble matter in polypropylene - specifies two validated methods to measure the mass fraction of polypropylene (homopolymer or copolymer) that is amorphous and therefore soluble in xylene at 25 °C. The standard includes a Method 1 (reference gravimetric method) and Method 2 (automated instrumental method) and replaces the 2005 edition with updated procedures, apparatus lists and an added automated technique.

Key topics and technical requirements

• Scope and principle
  • Quantifies the xylene‑soluble fraction (amorphous content) by dissolving polypropylene in xylene under reflux, cooling to 25 °C to allow crystallization of the insoluble fraction, then isolating and weighing the soluble residue (Method 1) or measuring it via an automated instrumental technique (Method 2).
• Apparatus and sensitivity
  • Typical equipment: 400 mm reflux condenser, 500 ml flasks, thermostatted water bath (25 °C ± 0.5 °C), magnetic stirrer, vacuum oven, analytical balance (min. 0.1 mg sensitivity; 0.01 mg preferred).
• Reagents and solvent preparation
  • Reagent‑grade o‑xylene (reference solvent) and p‑xylene specifications are given (GC assay ≥ 98 %, low ethylbenzene, low residue). Antioxidants (e.g., BHT) recommended for stabilization; a typical stabilizer level ≈ 0.02 g·L‑1 and degassing by nitrogen are described.
• Sample preparation and test portions
  • Drying instructions (e.g., vacuum oven at 70 °C ± 5 °C, <13.3 kPa) and guidance on test portion masses based on expected soluble content are provided.
• Quality controls
  • Solvent blank determination (evaporation residue), calibration procedures for automated method, and clauses on precision and bias (including informative interlaboratory precision data in Annex A).
• Test reporting
  • Required elements for a complete test report are specified.

Practical applications and users

• Who uses ISO 16152:2022
  • Polymer testing laboratories, quality control teams in polypropylene production, raw material suppliers, R&D groups, certification bodies and failure‑analysis labs.
• Why it matters
  • The xylene‑soluble fraction correlates with the amorphous content, influencing mechanical and optical properties (impact strength, clarity, processability). Accurate measurement supports material specification, batch acceptance, formulation development and comparative testing between producers or grades.
• Benefits of the automated method
  • Improved precision, reduced operator variability and enhanced laboratory safety compared with manual gravimetric procedures.

Related standards

• ISO 472 (Plastics - Vocabulary) is a normative reference used for terminology. ISO 16152:2022 was prepared by ISO/TC 61/SC 9 (Thermoplastic materials).

Keywords: ISO 16152:2022, xylene‑soluble matter, polypropylene testing, xylene‑soluble fraction, method 1 reference method, method 2 automated instrumental method, polymer characterization, plastics quality control.