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NanCore: Microcellular nanocomposite for substitution of Balsa wood and PVC core material
|Kinga Jurczuk , Andrzej Galeski , Ewa Piorkowska , Marcin Zarod , Jerzy Morawiec , Zbigniew Bartczak , Artur Rozanski , Ewelina Szkudlarek|
Polish Academy of Sciences, Center of Molecular and Macromolecular Studies (CMMS-PAS), Sienkiewicza 112, Łódź 90-363, Poland
CMMS PAS - contractor of Work Packages: WP2 and WP6 in the NanCore project. Andrzej Galeski, coordinator from Polish side
Project acronym: NanCore
Project full name: Microcellular nanocomposite for substitution of Balsa wood and PVC core material, NMP3-LA-2008-214148
Name of programme and competition: 7th Framwork Programme UE, Theme 4,
Application year: 2008
Implementation time of the project: 1st December 2008 - 30st November 2012
Participants of the project:
The principal objective of the NanCore project was to design a novel microcellular polymer nanocomposite (MPNC) foam, with mechanical properties and cost characteristics allowing for a substitution of Balsa wood and PVC foam as core material for lightweight composite sandwich structures. Specifically, the NanCore project aimed to achieve a cost reduction of at least 30 percent for the finished MPNC core material as compared to current core materials.
Project activities begun with manufacturing and end-user requirement specifications, proceeded to scientific and technological development within each of the project’s core problem areas, and finalized with test and demonstration of the developed core material. Project activities were divided into following Work Packages (WPs):
CMMS participated in several Work Packages of the NanCore project: mainly CMMS coordinated WP2. WP2 was focused on providing base materials for WP5, WP4 and WP3. The main task of WP2 was to prepare polypropylene, PP, nanomaterials with high melt strength, which would be used for foaming. CMMS developed and produced two types of nanocomposites including PP reinforced with polytetrafluoroethylene, PTFE, nanofibers and PP with montmorillonite, MMT.
The idea for simplification of producing nanocomposites with nanofibrillar reinforcement was to find a way to strongly deform crystalline inclusions (i.e. PTFE powder grains) during shearing or compounding and preserve the shape of generated PTFE nanofibers in the PP matrix. Pilot experiments on compounding devices using PP of high melt viscosity and reaction grade PTFE clearly showed that it is relatively easy to generate all-polymer nanocomposites with nanofibrillar reinforcement just by compounding the two polymers. One of the most interesting feature for NanCore project of PP+PTFE nanocomposite is its high melt strength and high extensional viscosity, the property that is required for efficient foaming. PTFE nanofibrils built up a continuous network, which proved to be necessary for melt strengthening even for PP matrix that originally does not show any melt strength. The discovery of the method of all-polymer nanocomposite fabrication was patented first in Poland and then applied for European patent.
CMMS established optimal preparation protocol for PP nanocomposites with nearly fully exfoliated MMT platelets, describing all steps of the process from clay drying to nanocomposite pelletizing. This protocol was also a base for preparation by IOM a document for health, safety and environmental precaution for research conducted in other WPs. A new staining method for the purpose of transmission electron microscopy, TEM, was developed to show compatibilizer localization in PP+MMT nanocomposites. Using osmium tetraoxide, it was possible to prove that compatibilizer adheres to MMT platelets in a semi-uniform fashion. It also confirmed that no platelets exfoliation could occur without compatibilizer surrounding. Observations were used in molecular modelling in AAU and KUL. CMMS also has proven that even a complete MMT exfoliation does not guarantee melt strengthening during the foaming process. Hence, the use of high melt strength PP for foamable nanocomposites is strongly advised and recommended.
The effort of CMMS in the NanCore project was also focused on nanocomposites foaming. CMMS gathered observational data linking foam structures with processing routes. Additionally, CMMS developed new foam examination method based on Neutron Magnetic Resonance. It showed that addition of MMT and foaming alters spin relaxation behaviour of CHx groups in PP chains. Data gathered from this method were used for modelling tasks.
Laboratory trials performed in CMMS have proven that melt strengthening of a nanocomposite is more important for foaming than the strength in solid state. During the up-scalling tests, it was also proved that heat transfer from interior of a foam and its dissipation is crucial in larger scale nanocomposites foaming. Following the problems with upscaling the foaming process, it was decided to use another foaming technique, focusing on micro-bead technology foaming. CMMS examined materials from all stages of industrial foaming trials. Micro-bead structure analysis revealed that foams have fully closed cell structure and have a density within the range desired by the project. Providing materials for successful foaming marks the success for the WP2. Both PP+PTFE and PP+MMT nanocomposites have foaming potential, which will be utilized during the future research and industrial trials.
The following industrial companies expressed their interest in applying developed polypropylene nanocomposites for foaming or moulding, all of them according microbead technology: ANTOS Chemical Co., Zamosc, Poland; HSV Co., the Netherlands; Izo-Blok, Poland; and Neue Materialien Bayreuth GmbH, Germany.
Presentation: Polish Research Projects at Nano and Advanced Materials Workshop and Fair, by Kinga Jurczuk
See On-line Journal of Nano and Advanced Materials Workshop and Fair
Submitted: 2013-06-30 19:34 Revised: 2013-06-30 19:55