Understanding the rheology of liquids, pastes, and melts is essential for both manufacturing performance and end-use applications across a wide range of industries. In processing environments, polymer melts and resins must be transported and shaped under shear flows, with flow behavior directly affecting success. For example, injection molding depends critically on how polymer melts flow, while molecular structure and morphology significantly influence extrusion behavior and processability. Adhesive deposition requires careful consideration of curing time and chemical reaction kinetics. Likewise, coatings such as paints and inks must be applied uniformly, at scale, and with maximum throughput.

Rheological properties also play a decisive role in high-speed processes—such as calendaring or roll-to-roll coating—where fluid behavior directly impacts throughput and final product quality. In medical device applications, fluids may serve as carriers for active ingredients, void fillers, or structural cements. In all cases, understanding rheology—and how materials interact with delivery mechanisms such as needles—is critical to ensuring reliable performance and ease of use.

Going Beyond Simple Rheology Testing

Routine testing methods often provide simple rankings of flow behavior, but most real-world fluids are highly complex and are not easily characterized with basic viscometers. This complexity applies not only to shear flows but especially to evolving systems (e.g., hydrogel gelation, adhesive curing) and entangled polymer systems (e.g., injection molding, coatings, or spraying processes where droplet formation and stringing are key concerns).

Even with a true rheometer, selecting the right experimental method and correctly interpreting results requires deep expertise. In more challenging cases, specialized tools such as the Capillary Breakup Extensional Rheometer (CaBER®) may be required. Cambridge Polymer Group’s expert rheologists design custom testing strategies, interpret results, and provide actionable recommendations for formulation optimization. Our state-of-the-art instrumentation and custom fixtures allow us to characterize materials across industries, from simple drug-delivery fluids to highly shear-sensitive drilling muds, curing adhesives, and yield-stress consumer products.

Our unique blend of processing expertise, fundamental rheology knowledge, and advanced instrumentation capabilities provides clients with the highest probability of success and the most valuable insights for material development and process optimization.

Expertise Across the Fluidic Spectrum

Cambridge Polymer Group combines decades of hands-on experience with innovative rheological techniques to deliver precise insights into fluid behavior. From low-viscosity Newtonian materials to complex shear-sensitive liquids and yielding plastics, our rheologists provide unmatched clarity into how your materials perform under real-world conditions.

Advanced Rheological Testing Techniques

Oscillatory Rheometry

  • Storage and Loss Modulus
  • Complex Viscosity
  • Strain-dependent properties
  • Yield stress determination

Steady Shear

  • Shear viscosity as a function of shear rate
  • First normal stress coefficient
  • Yield stress determination

Creep/Stress Relaxation

  • Material response to a fixed load or deformation

Time/Temperature Sweeps

  • Viscosity/modulus changes with temperature ramps
  • Melt temperature (or other thermal transitions)
  • Gelation and melting kinetics
  • Time-temperature superposition to generate master curves

Shear Rheometry

Shear rheometry is one of the most powerful material characterization tools, delivering insight from shelf-stability through high-shear extrusion and spraying. With a rheometer, we can evaluate curing behavior, temperature responses, yield stress, and formulation changes, providing direct feedback on processing and performance.

Standard methods available:

  • ASTM D7271 – Viscoelastic Properties of Paste Ink Vehicle (Oscillatory)

  • ASTM D4287 – High-Shear Viscosity (Cone/Plate)

  • ASTM D4440 – Plastics: Dynamic Mechanical Properties, Melt Rheology

Dilute Solution Viscometry

Capillary viscometry is a proven approach for determining molecular weight and structure information and remains a mainstay in quality control.

Standard methods include:

  • ASTM D2857 – Dilute Solution Viscosity of Polymers

  • ASTM D445 – Kinematic Viscosity of Transparent/Opaque Liquids

  • ASTM D3616 – Gel, Swelling Index, and Dilute Solution Viscosity of Rubber

  • ASTM D789 – Relative Viscosity of Concentrated Polyamide Solutions

  • ISO 1628 – Viscosity of Polymers in Dilute Solution

Melt Flow Rate

quality-control standard for thermoplastics, melt flow rate testing provides clear indications of changes in molecular weight, flowability, or formulation.

Standard methods include:

  • ASTM D1238 – Melt Flow Rates of Thermoplastics (Extrusion Plastometer)

  • ISO 1133 – Melt Mass-Flow and Volume-Flow Rates of Thermoplastics

Extensional Rheometry

Extensional properties determine how materials behave in processes such as spraying, atomization, calendaring, and gravure coating. Key measures include stringiness, droplet formation, breakup times, and relaxation times—critical predictors of performance in advanced manufacturing.

Custom Rheology Solutions

When standard approaches are insufficient, our multidisciplinary team develops custom test methods and fixtures to solve unique material challenges. With extensive experience across industries and access to specialized instrumentation, Cambridge Polymer Group provides targeted, practical, and high-value solutions.

Unlock the full potential of your materials with Cambridge Polymer Group’s rheological expertise.
Contact us for a consultation or quote.