Consortional main: Development of Innovative and Environmental Ways for Reactive Fire Retardancy of Polymer Systems Reinforced with Bio-fibres (InnoFiRetPolyBio)

Objectives

The project aims at development of fire retardancy methods for new bio-fibre reinforced, polymer nanocomposites and determine the mechanism of their degradation. The predicted growth of importance of biocomposites and nanocomposites is larger than any other materials but their fire resistance requires significant improvement in order to meet the expectations. Their combination is promising for ensuring enhanced mechanical stability and fire retardancy at good price/performance ratio. Breakthrough in the industrial applicability of bionanocomposites is expected from finding new economic and green chemistry approach for designing multifunctional materials for advanced sectors (e.g. automotive), where fire safety is of urgent need. The current project will contribute to the realization of advantages of nano-bio synergism through integrated synthetic; technological and product-engineering research. These include 1) synthesizing new advantageous additive systems; 2) contributing to better understanding of the relationship between the phase-structure and performance; 3) modification of the interfaces in order to control the stability; 4) development of new analytical methods for in line control of the performance during the production process. In line modification of polymers and interfaces will be performed with the synthesized substances. New methods for controlling the elaborated technologies and evaluating the performance of materials will be developed.

Results

Flame retardants (FRs) were synthesized for forming environmental and fire-safe plastics. Reaction product of P-compound with polyol was used in starch/PLA blends. Reactive FRs containing P and amine were synthesised and analysed by IR, 31P-NMR and MALDI-TOF. When applied in epoxy resin, the heat release rate decreased to 1/7 of the original value. Reaction between a P-polyol and 3-(triethoxysilyl)-propyl isocyanate yielded a reactive modifier for improving both the thermal stability of cellulosic fibres (even by 100°C) and the fiber-matrix adhesion. Diels-Alder cycloaddition of linoleic acid with maleic anhydride produced emulsifier for the synthesis of nano-FR Mg(OH)2, however, no Cl-free nano-FR formed. Polymer composites, combining the new FRs and polymers from secondary/renewable resources, were prepared developing fully recyclable/biodegradable versions. Nanocompatibilization was performed with nanofillers. Skin FR technology was realized by depositing sol-gel silica nanofibrous mats on PLA. Using the recently developed LP-FTIR method, gaseous degradation products of FR systems could be in situ analyzed. Self-extinguishing (V0) FR level was achieved with only 9% FR additive in PP. The mechanism of this outstanding performance is under examination. The rate of biodegradation was investigated under the standard effect of fungi, bacteria and soil; silane-modified biofibers became more resistant against microorganisms than the reference ones.