Berardini, Francesco (2008) Studio e sviluppo di compositi innovativi a matrice termoplastica per applicazione nel settore dei trasporti. [Tesi di dottorato] (Unpublished)
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|Item Type:||Tesi di dottorato|
|Uncontrolled Keywords:||compositi termoplastici, nanocompositi, proprietà meccaniche|
|Date Deposited:||13 Nov 2009 13:47|
|Last Modified:||30 Apr 2014 19:36|
Nano-/micro-composites based on polypropylene/MMT/calcium carbonate were prepared by melt mixing. Their structures and properties were characterized by small-angle X-Ray diffraction, thermal analysis, and rheological measurements. A Carreau-Yasuda model was used to model the rheological behaviour of these materials. The nano-/micro-composites showed a significant improvement (about 50%) of the Young’s modulus when compared to micro-composites with the same filler content due to the intercalation or exfoliation of the organoclay and the enhanced degree of crystallinity. The composite is build up by alternating layers of micro and/or nano reinforced thermoplastic matrix materials and woven fibre reinforcement. Micro and micro/nano-composites have the potential to improve the matrix dominated flexural properties of continuous fibre reinforced composites by means of increasing the matrix modulus. The effects of matrix composition, polymeric film thickness and processing conditions on viscoelastic and mechanical properties of the final multilayered thermoplastic composites are discussed. During this process, the thermoplastic matrix containing micro particles is squeezed out due to the flow of the macromolecular phase into the reinforcing woven fibers. The filler concentration in the interlayer is therefore higher than the initial value and the final multilayered composite structure is characterized by alternating layers of continuous fiber reinforced laminas of nanoreinforced matrices and micro-sized rich particulate composites. The damping properties of this structures can be therefore designed by tuning the initial composition of the particulate reinforced composites and its thickness in the multilayered structure.
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