Calorimetric Method To Determine Self-Accelerating Polymerization Temperature (SAPT) for Monomer Transportation Regulation: Kinetics and Screening Criteria

Abstract

The United Nations Recommendations on the Transport of Dangerous Goods, Model Regulations, Rev.19 (2015) has a new requirement for the determination of the SAPT (Self-Accelerating Polymerization Temperature) for polymerizing substances. Accordingly, polymerizing substances may be subject to temperature monitoring or temperature control depending upon their SAPT and type of transportation packaging. The requirement states the SAPT shall be determined in accordance with test procedures established for SADT (Self Accelerating Decomposition Temperature) for self-reactive substances. There are several SADT methods which differ in their measurement techniques. Recent work has shown that SADT results for materials with autocatalytic or autoaccelerated reactions can differ significantly depending upon which SADT method was applied. To ensure consistent SAPT values for safe transportation, several industry consortia committees (Basic Acrylic Monomer Manufacturers, European Basic Acrylate Manufacturers, and Methacrylate Producers Association), of which Dow is a member, met in a joint session and agreed to an intercompany effort to identify the best method on the basis of good science, readily available technology, and flexibility in packaging applications. This study highlights the technical approach developed and validated at Dow for inhibited methyl methacrylate (MMA) using isothermal micro calorimetry, modeling, simulations, and SADT H1 testing. In this paper, several calorimetric methods were evaluated and the corresponding kinetic equations describing the monomer polymerization were established. Isothermal experiments performed in micro calorimeters with a well-controlled temperature and high sensitivity were determined as the best method for estimating the polymerization kinetics. The studied monomer was methyl methacrylate, and the effect of inhibitor concentration, headspace volume, and mixing during sample preparation on PIT were carefully examined.

Thermal Instability and Associated Potential Safety Hazards of Rhodium(I) Precatalyst Complexes with Weakly Coordinated Ligands

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Kinetic analysis of the spontaneous thermal polymerization of acrylic acid

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