WoTIM Newsletter #4

Dear reader,

As the work within the WOTIM project proceeds, we are looking forward to, to a higher degree, involve the users of insulation materials in the discussions. On 26 April, Innventia will organize the second training module in Stockholm on Thermal insulation materials based on the cellulose. This event also welcomes participants outside the project with an interest in new materials for the construction industry. A draft agenda is presented in this newsletter. For more detailed and up to date information keep an eye on the web site www.wotim.eu. This newsletter also brings you recent findings from WP2 on the effect of fibre properties on foam forming and thermal conductivity.

Petri Jetsu,
VTT Project Coordinator

Training module WOTIM 2: “Thermal insulation materials based on the cellulose”

The second training module in the WOTIM project will focus on thermal insolation materials. This open seminar will among other things discuss the benefits of new cellulose based materials compared to commercial ones. The event will be arranged by Innventia in Stockholm, Sweden on 26 April, 2016.
Draft agenda:
  • WOTIM project presentation
  • Basics of thermal insulation
  • Commercial cellulose based insulation materials and manufacturing processes
  • Basics and status of foam forming
  • Comparison of foam formed insulation materials against commercial wood-based thermal insulation materials
  • Exhibition where different kinds of WOTIM materials are presented
Last day for registration is 11 April. For more information and registration see www.wotim.eu/trainingmodule2. Please spread the information about the event, we are hoping for a lively and fruitful discussion!

Fibre properties have large effect on foam formed insulation panel structure but little influence on measured thermal conductivity

Thick and porous fibre networks can be created by utilizing foam-laid forming technology. Wet aqueous foam with air content 50-70% is used as fibre transport medium. The air bubbles keep the fibres apart and with a high distance enabling forming of highly porous fibre structures. WOTIM project investigates the suitability of these bulky fibre network structures for thermal insulation in building envelopes.Three high production volume wood cellulose based pulp types were selected for the preparation of the insulation panels: Scandinavian softwood kraft cellulose (SW), Scandinavian hardwood kraft cellulose (HW) and lignocellulosic, mechanically defibrated wood pulp from Scandinavian spruce (TMP, thermomechanical pulp). All pulps were mill-made virgin pulps. Microfibrillated cellulose (MFC) was used as an additive to improve material strength.

Thermal conductivity (lambda value) of the panels was at its lowest when panel bulk density was higher than 40 kg/m3. The different pulp types induced fairly small differences in the thermal conductivity values. The lambda values around 34 mW/m·K are considered to be very good if compared with the current commercial cellulose fibre based insulation materials. Air flow resistivity and the mechanical properties of the panels can be adjusted by pulp selection: TMP pulp gave the highest air flow resistivity and the highest compression and bending strength. Mechanical properties of the panels can be still improved with the addition of microfibrillated cellulose.

Thermal conductivity

Thermal conductivity of the panels (EN 12667, measured at +20°C).