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John Gearing


Materials and Design

  • Analysis



Secondary Operations

  • Testing



Other Skills

The 3 main specialisation areas are:

  • For checking the THERMAL INSULATION properties of your plastic materials and composites, John Gearing offers a rapid and accurate service to BS874/ISO8301 for measuring the K - or lambda - values. Thickness from 100mm to 10mm - which could be several thinner sheets stacked up and results usually within several days. Using exclusively LaserComp Inc apparatus and results traceable to NIST (usa) standards.

  • DMA (Dynamic Mechanical Analysis) will give you the glass transition (softening point) and the relative stiffness (modulus) and damping from very low temperatures to 400ºC. These can vary with the vibration frequency and also the strain amplitude, and DMA shows this! As well as the normal bar-shaped sample, we can handle thin films, fibres and now POWDERS.

It is also over 1000 times as sensitive as DSC for a few milligrams of powders. Examples can be seen of lactose - 4 samples of which were prepared differently and the DSC showed no differences, yet DMA shows very clear ones.

  • Polymer calibration standards for GPC or Maldi-TOFS etc. where you wish to have a highly characterised few grams of research material of known molecular weight and polydispersity.

The polydispersity is usually very narrow, although some materials which are prepared by fractionation are rather broader!

John Gearing MA (Engineering Science), was author of the chapter on DMA in Marcel Dekkers’ book - "Handbook of Polymer Testing" - Editor Roger Brown, 1999. We have our own DMA/DMTA and this is often the best way to see subtle differences between a good and bad batch of “similar” materials. We can go from <-100C up to over 400°C as needed.

Over 18 years experience of thermal conductivity testing throughout Europe on most materials from liquids and mastics through to rigid plastics or composite samples as well as the common vacuum panels and foamed plastics. We also now have the software to measure specific heat over a wide temperature range – and for composites in particular, this is more relevant than the DSC few milligrams sized sample. T range from -10C to 250°C or less depending on type of material, flash points etc.

Over 30 years experience in GPC/SEC with a particular interest in producing very narrow (low polydispersity) polymer standards through living ionic polymerisation or in the case of nylon or PVC through prep GPC fractionation. We offer such narrow standards throughout Europe from: www.ampolymer.com and www.polymersource.com in particular – whose stock lists and prices can easily be seen by visiting their websites. We convert into pounds sterling or Euros and then add the one-off shipment charge.

Contact Address

Gearing Scientific Ltd., The Old Rectory,  Seven Sisters Road, St Lawrence, Isle of Wight,  PO38 1UZ,  UK

Tel: 01983 852 211

email: gearingsci@yahoo.com

Web: www.gearingscientific.net