1. Final Report Summary - NANOHYBRID (Designed Nanostructured Hybrid Polymers: Polymerisation Catalysis and Tecton Assembly)
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Abstract: Learning from nature, the major objective of the NANOHYBRID project was to develop fundamental knowledge in order to be able to elaborate new melt processable nanophase-separated hybrid materials with controlled architecture, derived from low cost petrochemical olefin feedstocks without sacrificing easy polymer melt processing.
To achieve the global objective leading to the design of melt processable nanophase separated polyolefin hybrid materials usable in various industrial applications the project focused on:
- Creation of new knowledge related to macromolecular architecture designs via transition metal catalysis which would open up access to novel random and block copolymers (BCs) and polymer product compositions.
- Understanding the phenomena of nanocompomers' and nanocomposites' formation either during in-situ polymerisation or during melt processing.
- Investigation of fundamental characteristics of the organic-inorganic interphase region by multi-scale analysis.
- Various applications were targeted in the long term.
The work that was performed can be summarised in the following:
- Catalysts: Novel transition metal and rare earth metal catalyst systems were synthesised: i) a number of monocyclopentadienyl Ln compounds (Ln = Sc, Y, Lu) for the controlled polymerisation of olefinic and polar monomers; ii) cobalt and iron based (imino)pyridyl systems for the contemporaneous oligomerization/polymerization of ethylene. The rare earth complexes were tested for styrene, olefin, and ethylene-norbornene copolymerization.
- Novel polymers and block copolymers: The conditions under which newly developed bisphenolato metal complexes allow living styrene polymerizations were investigated. Kinetics experiments to demonstrate the living ethylene-norbornene copolymerization with scandium dialkyl catalysts were performed. Investigations on random copolymerization of norbornene bearing polar groups (-CH2OH) as well as experiments to synthesize di-block copolymers having one block based on ethylene-norbornene copolymers and one block containing functionalized norbornene were carried out.
- Tectons and nanostructured hybrid polyolefins: Different doped and non-doped aluminas, silica-aluminas, and hydrotalcites aluminas to cover a wide range of surface acidities were developed. Organic acids were used to modify the alumina. Methods for the production of multiwall carbon nanotubes and for the controlled functionalisation of carbon nanotubes were designed and tested.
The NANOHYBRID material would be of special interest for the upgrading and diversification of polyolefin compositions produced by transition metal catalyzed polymerisations. The production of polyolefin materials offers economical, environmental and application-oriented advantages:
- Economical: It is an important industrial sector accounting for more than half of the 1modern 200 million ton/year plastics production.
- Environmental: Polyolefins are prepared in highly effective catalytic processes requiring low energy and preserving the oil-like energy content of polyolefins. Upon heating above 300 degrees Celsius, the polyolefins degrade to recover synthetic oil and natural gas.
- Industrial Applications: as a function of catalyst type, process conditions, polymer processing and especially the type of olefin copolymer and functional fillers, it is possible to tailor a wide variety of materials which meet the demands of modern technologies ranging from packaging and low weight engineering materials to communication technology.
- Application-oriented property enhancement, thanks to nanostructured hybrid polyolefins. Tecton and hybrid approaches to advanced nanostructured polymers via catalytic polymerisation combined with block copolymer self-assembly can offer unique benefits and opportunities for new applications and products.
Fundamental knowledge to create new melt processable nanophase-separated hybrid materials with controlled architecture, derived from low cost olefins was developed. This was testified from the great number of publications in JCR.
Novel nanoparticles were created:
i) organophilic inorganic polyelectrolyte nanoparticles (such as different doped and non-doped aluminas, silica-aluminas, and hydrotalcites to cover a wide range of surface acidities);
ii) carbon nanotubes (such as well defined MWNT and DWNT, as well as functionalised CNTs.
Novel catalysts for living based on rare-earth metal bisalkyl half-sandwich complexes and homogeneous tandem polymerisation were created. These achievements allowed to create novel polymer architectures, novel random and block copolymers with polar and apolar blocks and polymer product compositions in order to improve matrix/filler adhesion and nanofiller dispersion.
Catalyst were supported on the tectons for in situ (filling) polymerisation to produce nanoparticles coated with polymer, which were used intermediates to obtain novel nanohybrids with high inorganic content. Complex melt processable polyolefin hybrids were designed. NANOHYBRID nanocomposites, with a very small amount (a few weightpercent) of nanometer-scaled anisotropic tectons, combining chemical and physical bonding between nanofiller and matrix were obtained which was a real breakthrough in material's properties.
Examples of enhanced properties are:
i) Mechanical properties of PE/Dispersal hybrid materials like Young's Modulus and yield stress could be improved without the expense of high elongation at break.
ii) An increase in flexural elastic modulus (FEM) and heat distortion temperature (HDT) the best performance is with no doubt expressed by the Cloisite 15A from Southern Clay Product (50 % enhancement of FEM).
iii) Electrical properties of Nano-composite with CNT increase the electrical conductivity with only 0,2 % of CN.
Among the various applications which were explored in order to assess the capabilities of the NANOHYBRID material those that could be further developed to industrial processes in the medium to long term were:
- Materials design for automotive parts:The realization of an automotive component (interior trim) made of polypropylene (PP) by injection moulding process was optimised.
- Advanced functional materials for communication technology.
- Advanced functional materials for high performance elastomers.
- Polymer MEMS (micro-electro mechanical system) components: The fabrication process of the MOEMS device was optimised introducing the OS1 nanofiller.
- Nanocomposite polyolefin fibres for textile.