The influence of pre-treatment of Spartium junceum L. fibres on the structure and mechanical properties of PLA biocomposites

Different chemical pre-treatments of Spartium junceum L. fibres using alkali (NaOH), nanoclay (MMT) and Citric acid (CA) with the aim of producing biodegradable composite material are discussed. As environmental requirements in processing technologies have been higher in recent years, the Polylactic acid (PLA) is used in this research as a matrix, due to its renewability, biodegradability and biocompatibility. Biocomposites are prepared by reinforcing PLA with randomly oriented, short Spartium junceum L. fibres in order to increase material strength. The effects of different pre-treatments of Spartium junceum L. fibres on the mechanical properties of final biocomposite material are examined. Fibre tenacity is studied using Vibroscop and Vibrodyn devices. Tensile strength of biocomposite material was measured on the universal electromechanical testing machine Instron 5584. The results indicate that biocomposites reinforced with fibres modified with MMT and CA show upgraded mechanical properties of the final composite material in comparison with the composite materials reinforced with referenced (nontreated) fibres. Infrared spectra of tested fibres and biocomposites were determined with Fourier transform infrared spectroscopy using Attenuated total reflection (FT-IR ATR) sampling technique and the influence of fibre modifications on the fibre/polymer interfacial bonding was investigated. The interface of Spartium/PLA composites was observed with scanning electron microscope (SEM) and it was clearly visible that biocomposites reinforced with fibres modified by MMT and CA showed better interaction of fibres and matrix.British Scholarship Trust; Croatian Science Foundatio

Interlaminar fatigue crack growth behavior of MWCNT/carbon fiber reinforced hybrid composites monitored via newly developed acoustic emission method

The aim of this research was the investigation of the effect of carbon nanotube addition on the mode I interlaminar fatigue properties of carbon fiber reinforced composites. The authors developed a localization methodology to track the interlaminar fatigue crack front using the acoustic emission (AE) technique. According to the test evaluation the carbon nanotube reinforcement decreased the crack propagation rate by 69% compared to the composite containing no nanotubes. Besides that, the fatigue life also increased significantly, the nanotube reinforced composite could withstand 3.8-times more cycles to failure than the unfilled matrix composite

Solar neutrino spectroscopy (before and after superkamiokande)

hep-ph 9611435Biblioteca Centrale CNR / CNR - Consiglio Nazionale delle RichercheSIGLEITItal