Particle characterisation key to understanding raw materials

Paul Boughton

For chemical companies to be able to store, move and use their raw materials effectively, an understanding of each material's particle characteristics is essential. Eugene McCarthy explains.

In a new web-based seminar from Malvern Instruments the company's 'nylon characterisation technology package' is explored. The webinar outlines how the utilisation and combination of several analytical technologies employed within Malvern's Viscotek family of instruments are assisting manufacturers of nylon to precisely control physical properties, processability and performance characteristics.

Nylon (the generic name for a family of polyamides) is an extremely versatile synthetic thermoplastic that is made of repeating units linked by amide bonds.

It is widely known that nylon fibres are manufactured for products such as fabrics, carpets, strings and ropes, and as solid nylon in mechanical parts for construction, automotive assemblies and many houseware items.[Page Break]

Molecular weight distribution

Manufacturers rely on important and complementary information about molecular weight distribution, structural characteristics and viscosity to better control the physical properties, processability and performance characteristics for these diverse applications.

The webinar highlights how the techniques of gel permeation chromatography (GPC), flow injection polymer analysis (FIPA) and dilute solution viscosity (DSV) combine to efficiently meet this important analytical need, from development through to manufacturing and quality control (QC).

GPC analysis provides extensive molecular information to support the development of new specifications for defined applications and the optimisation of manufacturing processes. It is a cornerstone technique for polymer scientists, enhanced through the use of multiple detectors that maximise information from each experiment.[Page Break]

Viscosity measurement

The Viscotek DSV system is a highly automated option for fast, safe and efficient intrinsic viscosity measurement, a primary parameter for determining processing performance (Fig.1). FIPA is a tool for rapid molecular weight, molecular size, and intrinsic viscosity measurement, well-suited to QC and screening within process development. Unlike GPC it does not provide distributions of molecular properties, but the upside is productivity - as many as 6-10 samples can be measured per hour.

The presentation is free to view, register here:

New experimental data from Freeman Technology demonstrate how dynamic, shear and bulk powder testing can be applied to quantify the impact of humidity on powder behaviour, supporting the need to develop effective strategies for moisture control and process optimisation. 'Quantifying the impact of humidity on powder properties' by Freeman's powder technologist Brian Armstrong and operations manager Jamie Clayton is now available for download at the company website:

Of the many factors that influence powder behaviour, moisture, or humidity, is perhaps one of the most instantly recognised and potentially one of the most problematic. Adding even small amounts of water to a powder can transform its properties. The challenge for formulators and process engineers is to understand the extent to which a powder will take up moisture and, more importantly, how this will affect the powder and its performance.[Page Break]

Impact of humidity

The new white paper explores the impact of humidity through the application of dynamic, shear and bulk property testing using Freeman Technology's FT4 powder rheometer. Together these techniques reliably quantify how powder behaviour changes as a result of moisture uptake, providing the comprehensive insight needed to develop effective strategies for moisture control and process optimisation.

The FT4 Powder Rheometer delivers information that helps powder processing industries to maximise process and product understanding, and accelerate R&D, formulation and commercialisation, as well as supporting process optimisation. FT4 systems are installed in many different sectors, including the chemical, pharmaceutical, toners, foods, powder coatings, metals, ceramics, cosmetics and other industries.[Page Break]

Advances in software

Micromeritics' new innovative MicroActive data analysis software allows users to interactively evaluate isotherm data from Micromeritics' ASAP, TriStar, and Gemini gas adsorption instruments.

Interaction with adsorption data is direct. Users can easily include or exclude data, fitting the desired range of experimentally acquired data points. Interactive data manipulation minimises the use of dialogue boxes to specify calculation parameters allowing accurate and efficient determination of surface area and porosity of their materials. By simply moving calculation bars with the cursor, the user is immediately updated with the new textural properties.

One-click access to important parameters allows the user to focus on the result rather than the parameters. It is not necessary to generate reports to view results - now see it graphically and interactively on the screen.

Screen layout has been designed to provide a user-friendly interface. Rapidly switch between a user-selectable experimental data view and traditional advanced or basic views. Isotherms can be viewed on either a linear or logarithmic scale, available to the user under each calculation model.

Many gas adsorption models are included - all using the isotherm data.

Reports include Isotherm, BET surface area, Langmuir surface area, t-plot, BJH adsorption and desorption, Horvath-Kawazoe, DFT pore size, and Dubinin.[Page Break]

High-speed approach

VisualSpreadsheet V3.2-enabled FlowCAM replaces cumbersome, manual microscopy and volumetric-based systems such as laser diffraction that assume all particles to be spherical with a modern, high-speed approach that bases measurements on actual, individual images, which permits the amount of curl or straightness to be reliably calculated.

The new VisualSpreadsheet V3.2 is an intuitively easy to use spreadsheet-based interface for viewing the images and measurement data and analysing the data in a variety of custom graphs and overlays while also filtering and sorting in real-time without re-running the sample.

The particle analyser software comes installed with the FlowCAM instrumentation and is backwards compatible for retrofit on FlowCAM models in the field.

Finally, HORIBA has concluded a basic contract with the Beijing Centre for Physical and Chemical Analysis (BCPCA), a state-owned research institute in Beijing, China, to establish a joint R&D centre, aiming to facilitate collaborative research on new analysis and measurement methods and equipment.

Since establishing the HORIBA Application Laboratory in BCPCA in 2001, the company has built a relationship of trust with BCPCA by providing its analysis and measurement services, as well as technology exchanges.