ASTM D7252-22 PDF
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St ASTM D7252-22
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Ст ASTM D7252-22
Original standard ASTM D7252-22 in PDF full version. Additional info + preview on request
Full title and description
Standard Test Method for Polyurethane Raw Materials: Determination of Monomer and Isomers in Isocyanates — ASTM D7252-22. This test method specifies a liquid‑chromatographic procedure to quantify the percent by weight of monomeric isomers and total monomer in crude or modified isocyanates (MDI and PMDI) used as polyurethane raw materials; samples are derivatized with methanol to methyl urethanes and analyzed by normal‑phase HPLC with internal standard quantification.
Abstract
ASTM D7252-22 provides a validated procedure for the determination of monomer content and isomer distribution in methylene di(phenylisocyanate) (MDI) and polymeric MDI (PMDI) raw materials. The method uses methanol derivatization followed by normal‑phase high performance liquid chromatography (HPLC) and UV detection to separate and quantify derivatized isomers against an internal standard. It is intended for research and quality‑control characterization of isocyanate feedstocks.
General information
- Status: Active (current edition D7252-22; Active, last updated July 12, 2022).
- Publication date: 2022 (designation D7252-22; published/issued in 2022 — listed as 01/07/2022 on catalog records; ASTM listing shows last update July 12, 2022).
- Publisher: ASTM International (ASTM).
- ICS / categories: 19.020 (Test conditions and procedures in general); 83.040.01 (Raw materials for rubber and plastics); 83.100 (Cellular materials).
- Edition / version: D7252-22 (2022 revision). Previous editions include D7252-17, D7252-06.
- Number of pages: 6 pages.
Scope
This test method determines the percent by weight of monomeric isomers and total monomer in crude or modified isocyanates, specifically applicable to methylene di(phenylisocyanate) (MDI) and polymeric MDI (PMDI). The standard states SI units are to be regarded as standard and notes there is no known ISO equivalent. It also reminds users to observe appropriate safety, health, and environmental practices when handling isocyanates.
Key topics and requirements
- Derivatization: Reaction of isocyanate sample with methanol to form methyl urethanes prior to chromatographic analysis.
- Chromatography: Normal‑phase HPLC separation (cyano stationary phase recommended: 250 mm × 4.6 mm, 5 μm nominal).
- Detection and conditions: UV detection (example wavelength 235 nm), column temperature control (≈30 ± 0.2 °C), typical flow rates 1–3 mL/min, reproducible injection volumes (≈2 μL).
- Quantification: Use of an internal standard and peak‑area integration to report percent by weight of individual monomeric isomers and total monomer.
- Applicability: Method designed for both crude and modified isocyanate raw materials (MDI/PMDI) used in polyurethane manufacture.
- Limitations and safety: Standard does not address all safety concerns; users must establish appropriate safety and regulatory practices for handling isocyanates.
Typical use and users
Primary users are analytical laboratories, QC/QA departments in polyurethane and isocyanate manufacturing, raw‑materials suppliers, polymer research groups, and regulatory/test laboratories that require reliable measurements of monomer content and isomer distribution in MDI/PMDI. The method is used for batch release testing, incoming raw material checks, troubleshooting product quality, and R&D comparisons.
Related standards
Related or predecessor documents include earlier editions of the same method (D7252-17, D7252-06). The method is developed under ASTM committee work for polyurethane raw materials (subcommittee D20.22). The standard notes there is no known ISO equivalent. For interlaboratory precision data, see associated research report RR:D20-1243 which supports precision/bias estimates for D7252.
Keywords
isocyanate, MDI, PMDI, monomer content, isomers, methyl urethane derivatization, HPLC, normal‑phase chromatography, internal standard, polyurethane raw materials, quality control, ASTM D7252-22, DOI 10.1520/D7252-22.
FAQ
Q: What is this standard?
A: ASTM D7252-22 is a Standard Test Method that specifies a chromatographic procedure to determine percent by weight of monomeric isomers and total monomer in MDI and PMDI isocyanate raw materials (2022 revision).
Q: What does it cover?
A: It covers sample derivatization with methanol to form methyl urethanes, separation by normal‑phase HPLC (recommended cyano column), UV detection and quantification using an internal standard to report monomer and isomer results for crude or modified isocyanates.
Q: Who typically uses it?
A: Analytical and industrial laboratories, QA/QC teams in polyurethane and isocyanate production, raw material suppliers, and research groups needing reproducible monomer/isomer measurements for product characterization and quality control.
Q: Is it current or superseded?
A: The D7252-22 revision is the current active edition (designation D7252-22). ASTM lists the document as active and shows a last update on July 12, 2022; earlier editions include D7252-17 and D7252-06. Users should confirm they are using the active 2022 edition for the latest requirements.
Q: Is it part of a series?
A: It is a single test method within ASTM’s portfolio for plastics and polyurethane raw materials maintained by the relevant ASTM technical committee and subcommittee (D20 / subcommittee D20.22). It has companion interlaboratory reports and related analytical methods under the D20 committee.
Q: What are the key keywords?
A: HPLC, isocyanate, MDI, PMDI, monomer, isomers, methyl urethane, derivatization, internal standard, polyurethane raw materials, quality control.