EN ISO 11409:1998 PDF

Overview

EN ISO 11409:1998 (identical to ISO 11409:1993) specifies a differential scanning calorimetry (DSC) method for determining heats and temperatures of reaction of phenolic resins. The standard covers resols and novolak-based systems (for example, novolaks mixed with hexamethylenetetramine) that show exothermic cure behaviour. The method measures heat flux versus time or temperature; exothermic reactions produce peaks whose integrated area gives the reaction energy (enthalpy), while peak position yields reaction temperatures.

Key topics and technical requirements

• Principle: measure differential heat flux between sample and reference during a controlled temperature program and integrate exothermic peaks to obtain heats of reaction.
• Typical sample types: resols, novolaks + hardeners (e.g., hexamethylenetetramine); small representative powdered/granular samples are required.
• Apparatus requirements:
  • Differential scanning calorimeter (DSC) with heat-flow recording and automatic differential signal.
  • Heating/cooling capability up to about 10 °C/min; recommended test heating rate 5 °C ± 1 °C/min.
  • Temperature resolution to at least ±0.1 °C; operating range preferably 20–300 °C.
  • Sensitivity and time-base precision to ensure measurement uncertainty around ±1 %.
• Sample holders: pressure‑tight, inert, high‑conductivity capsules (steel capsules recommended), pressure-tight to 2 MPa to retain volatiles.
• Sample mass and handling:
  • Typical sample mass order: 2–10 mg, weighed to 0.05 mg accuracy.
  • Discard results if mass loss during scan exceeds 10 %.
• Calibration and measurement:
  • Calibrate heat axis and time base (electrical or reference material). Indium is recommended as a reference (melting point 156.6 °C; heat of fusion ~28.42 J/g).
  • Construct baselines, measure peak areas (average of repeated integrations or electronic integration), and calculate heat of reaction normalized to sample mass.
• Reporting: include instrument details, sample preparation, heating rate, calibration method, heats (J/g), onset and peak temperatures, mass loss and thermogram copy.

Applications and users

• Practical uses: formulation development, quality control, cure kinetics screening, batch-to-batch comparison and R&D of thermosetting phenolic resins.
• Typical users: polymer scientists, materials labs, QC departments in resin and composites manufacturing, academic researchers working on cure behaviour and thermal characterization.
• Keywords: EN ISO 11409:1998, phenolic resins, differential scanning calorimetry, DSC, heats of reaction, resols, novolaks, hexamethylenetetramine.

Related standards

• ISO 472 (Plastics - Vocabulary)
• ISO 5725 (Precision of test methods)
• ISO 10082 (Phenolic resins - Definitions and test methods)
• IEC 1074 (DSC methods for melting/crystallization)