ASTM D2236-81 PDF

Full title and description

Standard Method of Test for Dynamic Mechanical Properties of Plastics by Means of a Torsional Pendulum — ASTM D2236-81. This test method describes use of a torsional‑pendulum apparatus to determine the dynamic (viscoelastic) shear response of plastic materials (storage and loss components of the complex shear modulus, and related damping/tan δ behavior) as a function of temperature and small strain oscillatory loading.

Abstract

ASTM D2236-81 is an ASTM test method (torsional‑pendulum technique) intended to measure dynamic mechanical properties of plastics: elastic (storage) and viscous (loss) components of shear modulus, damping behavior and temperature‑dependent transitions such as glass transition. The 1981 designation (D2236-81) represents an edition of a method that has since been withdrawn; the method historically provided a simple resonant/free‑vibration torsion technique appropriate for specimens and materials with logarithmic decrement ≤ 1.

General information

• Status: Withdrawn (listed withdrawn in archival catalogs; edition D2236-81 appears as a withdrawn ASTM test method).
• Publication date: 1981 (designation D2236-81). Earlier related edition published 1970 (D2236-70).
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: 83.080.01 — Plastics in general (dynamic mechanical testing / viscoelastic properties).
• Edition / version: D2236-81 (edition year indicated by suffix -81).
• Number of pages: ~6 pages (catalog listings for the D2236-81 product record report ~6 pages).

Scope

This method specifies a torsional‑pendulum procedure to determine the dynamic shear (complex shear modulus) components of plastics under small amplitude oscillatory torsion, across a range of temperatures and at frequencies appropriate to the apparatus (resonant/freely vibrating torsion pendulum). Typical outputs include storage modulus, loss modulus, damping (tan δ), and identification of thermomechanical transitions (for example glass transition). The technique is best suited to materials and specimen geometries compatible with torsional resonance and for materials exhibiting moderate damping.

Key topics and requirements

• Principle: free/resonant torsional vibration of a specimen + measurement of period and decay to derive moduli and damping.
• Measured properties: storage (elastic) modulus, loss (viscous) modulus, complex shear modulus, and tan δ (damping).
• Specimen geometry and conditioning: dimensions and conditioning consistent with linear viscoelastic assumptions and with the torsional‑pendulum fixture; environmental (temperature) control required.
• Data interpretation: temperature (and frequency) dependence used to locate transitions (e.g., Tg) and compare viscoelastic performance.
• Limitations: method is a specific resonant torsion technique and may be superseded by more modern DMA practices and instruments offering broader frequency/temperature ranges and multiple deformation modes.

Typical use and users

Used historically by polymer/materials laboratories, R&D teams, and quality/control labs for characterization of viscoelastic shear behavior and transition temperatures of plastics. Typical users include plastics manufacturers, composites developers, academic researchers studying thermomechanical behavior, and testing labs where torsional resonance equipment is available. Regulatory or specification writers sometimes referenced earlier editions when specifying test procedures in material procurement or compliance documents.

Related standards

Contemporary or related standards and practices that cover the same domain of dynamic mechanical testing include ASTM D4065 (practice for dynamic mechanical properties and reporting), ASTM D5279 (dynamic mechanical properties in torsion), ASTM D5026 (dynamic mechanical properties in tension), and international standards such as ISO 6721‑2 (torsion‑pendulum method). Users typically refer to these newer/active standards and ASTM practices for modern DMA testing and reporting.

Keywords

torsional pendulum, dynamic mechanical properties, DMA, storage modulus, loss modulus, tan delta, viscoelasticity, glass transition, plastics testing, ASTM D2236.

FAQ

Q: What is this standard?

A: ASTM D2236-81 is (or was) an ASTM test method titled "Standard Method of Test for Dynamic Mechanical Properties of Plastics by Means of a Torsional Pendulum" describing a torsional‑pendulum technique for measuring dynamic mechanical (viscoelastic) shear properties of plastics.

Q: What does it cover?

A: It covers specimen resonance torsional testing to determine storage and loss components of shear modulus, damping (tan δ), and the temperature dependence of these properties (useful for locating transitions such as Tg) for plastics compatible with the torsion apparatus.

Q: Who typically uses it?

A: Polymer and materials testing laboratories, manufacturers, R&D groups, and academic researchers historically used this method; today, users more commonly follow modern DMA practices and ASTM methods (see D4065, D5279, D5026) or ISO equivalents.

Q: Is it current or superseded?

A: The D2236-81 designation is listed as withdrawn in catalogs of archived standards. Modern dynamic mechanical testing is covered by active ASTM practices and test methods (for example ASTM D4065 and specimen/mode‑specific methods such as D5279 or D5026) and by ISO 6721 family methods; those are the recommended references for current practice.

Q: Is it part of a series?

A: D2236 belonged to the body of ASTM D20 (Plastics) mechanical test methods and sits conceptually within the family of dynamic mechanical test methods for plastics. Modern related entries in the D20 portfolio include practice D4065 and test methods D5279, D5026, etc.

Q: What are the key keywords?

A: Torsional pendulum; dynamic mechanical analysis (DMA); storage modulus; loss modulus; tan δ; viscoelastic; glass transition; plastics testing; ASTM D2236.