DYNAMICAL MECHANICAL ANALYSIS (DMA) SERVICES

DYNAMICAL MECHANICAL ANALYSIS SERVICES

Dynamical mechanical analysis (DMA) is a technique used to study the changes in the mechanical properties of a given material under periodic stress, as the temperature is varied.

A DMA analysis experiment involves an oscillatory force applied at a set frequency to a sample suspended in a near-frictionless environment. The instrument then subjects the sample to changes in temperature (either heating or cooling) as the dynamic stress is simultaneously applied. The material’s response over time, as a function of applied temperature/frequency/stress, is measured as damping of its oscillation, and dimensional changes in its shape, by an ultra-sensitive detector. The resultant data can be used to derive numerous thermomechanical properties.

APPLICATION AREAS FOR DMA:

DMA analyses are a highly cost-effective and ubiquitous tool to study material properties of interest to numerous industries. It is exceptional in characterizing the viscoelastic behavior of polymers, and in this area has been used to characterize materials from pharmaceutical capsules and biomedical devices to semiconductor and electronics casings, circuit boards and connections; and from industrial packing materials to aerospace devices.

MEASUREMENTS:

  • Glass transition temperature
  • Melting point
  • Storage (elastic) Modulus, Loss Modulus, Flexural Modulus, and Young’s Modulus (all limited to very small samples)
  • Strain-to-Break
  • Toughness
  • Creep
  • Stress Relaxation
  • Softening point and heat deflection temperature
  • Gel and vitrification times
  • Degree of swelling
  • Isothermal cure of supported samples (e.g. mounted on wire mesh, glass fibers, filter paper)

Uses & Limitations:

  • What it is great for:
    • Ultra-high sensitivity to deformation and displacement
    • Better detectability for thermal transitions (e.g. melting, glass transition) than DSC
    • Tremendous flexibility in experimental design to investigate a wide range of properties
    • Rapid and straightforward data collection with minimal sample prep
    • Particularly well suited to high-stiffness applications
  • Limitations:
    • Data quality hindered for rough, asymmetric and/or irregularly shaped samples
    • The sample size is limited by instrument

Example outputs

DMA temperature sweep measuring modulus (storage and loss) plus thermal properties measurement (Tg and Tm)

DMA creep measurement of polyethylene film under constant load

INSTRUMENTS

TA Instruments Q800 DMA
The Q800 DMA system was the world’s best-selling DMA. It is equipped with a state-of-the-art, non-contact linear drive system to precisely and accurately mediates a stress application from 0.0001 to 18 N, at frequencies from 0.01 to 200 Hz, with minimized friction. The system measures strain using patented optical encoder technology that provides ultra-high sensitivity and displacement resolution (to 1nm!). A fully rotational sample holder is enclosed in the Q800 DMA’s mobile, digitally controlled, and auto-cooled furnace, allowing for constant or variable temperatures of -150 to 600 °C to be precisely regulated throughout the operation.