Advanced Materials Research Vol. 747

Abstract: The fibrous plants can grow from Northern to Southern Arctic Circle. Different parts of these lignocellulosic plants are valuable sources of lignocellulosic fibres used in textiles and eco-friendly composites, sources of human food, nutrients, animal feed, agro-fine-chemicals for cosmetics and other area of application. That they are completely sustainable, renewable, and biodegradable and they recycle the carbon dioxide (CO₂). Fibrous plants were well known to mankind more than 7 000 BC. Some of these bast fibrous plants like flax and hemp could be explored for reclaiming the soil polluted by heavy metals. The total production of all natural fibres is expected at the level 35-40 million tons/year. Special treatment and functionalization of these fibres provides new promising features and expected new properties of these fibres. Natural fibres can be processed for production of woven goods, knitting, nonwoven, technical and 3D textiles, also as the reinforcement of more friendly composites. These whole plants and woody parts (shives) and fibres can be used for production of special pulp and paper and seeds some for obtaining the agro-fine-chemicals. Natural fibres and derived products have very important properties like: excellent air permeability, high hygroscopicity, high heat absorption, no release of substances harmful for health, they not cause allergy effect, as well as safer behaviour in flame and fire combustion versus man-made fibres. The new emerging method of genetic modification (GM) of these fibrous plants provides promising performance e.g. higher level of cellulose, possibility of creating polyhydroxy-alcanate (PHA) natural polyester in statu nascendi. Such GM modified plants are resistant to special herbicides, better resistant to drought also with controlled level of lignin and pectin.In 21st century the coexistence and competition between man-made and natural fibres is stabilized, especially in area of quality, sustainability and economy of their production.

Abstract: Composites sheets based on short wool fibres and polypropylene were fabricated by extrusion process. A three-factor two-level experimental design using Taguchi method was applied in manufacturing the composites to explore the contribution of each parameter on mechanical properties. Fire retardant behaviour of the composites with different fibre weight ratios was investigated by horizontal burning test and cone calorimetric analysis without the addition of any fire retardant agent. Reduction of burning rate with increase in the wool fibre content was observed and suitable formulation of the composites was selected for evaluation of mechanical properties.

Abstract: Poly (ethylene-co-vinyl acetate) (EVA)/clay nanocomposites with different clay loadings were prepared. The transport of gases (oxygen and nitrogen) through the composite membranes was investigated. These studies revealed that the incorporation of nanoclays in the polymer increased the efficiency of the membranes toward barrier properties. It was also found that the barrier properties of the membranes decreased with clay loadings. This is mainly due to the aggregation of clay at higher loadings. The mechanical properties of the nanocomposites were analysed. Samples with 5 wt % Cloisite 15A clay showed superior performance in tensile strength and elongation at break.

Abstract: Continuous fibre (carbon or glass) composite laminates with an epoxy matrix modified by nanoparticles (nanosilica of 25 nm or nanocarbon of 35 nm) were fabricated using a vacuum assisted resin infusion technique, aided by hot pressing, that produces high performance composites of a fibre fraction over 60 vol%. The presence of nanoparticles enhances fibre-matrix adhesion, the transverse tensile strength, the unidirectional compression strength, and mode I interlaminar fracture toughness. In particular, the GF/EP composites with the conductive nanoparticles allow the in-situ monitoring of damage (e.g. delamination) growth and impact damage assessment using a novel method of electrical resistivity tomography.

Abstract: A series of polystyrene (PS) nanocomposites with various concentration of organomodified Ni-Al LDH (3, 7 wt%) were synthesized by solvent blending method and the effect of Ni-Al LDH content on the thermal properties and degradation kinetics of PS/ Ni-Al LDH nanocomposites was examined. Thermogravimetric analysis (TGA) was employed to evaluate the thermal properties of the prepared PS nanocomposites with various content of Ni-Al LDH. The obtained TGA results reveal that the PS/Ni-Al LDH nanocomposites exhibits enhanced thermal stability when compared with pure PS and the thermal stability of the nanocomposites increase with an increase in the LDH content from 3 to 7 wt%. When 15% weight loss is selected as a point of comparison, the thermal decomposition temperature of the PS/Ni-Al LDH nanocomposite containing 7 wt% of LDH is about 28°C higher than that of pure PS. The thermal degradation kinetics of the nanocomposite materials are investigated using two kinetic models such as Flynn-Wall-Ozawa method and Friedman method. The improvement of thermal stability of the nanocomposites with increasing LDH content is also validated by increasing the activation energies.

Abstract: The FePt (30 nm)/NiO (2 nm) bilayer films with or without an intermediate layer were deposited on Si substrate at ambient temperature by magnetron sputtering. The films were then post-annealed at 700 °C for 3 min by Rapid Thermal Annealing (RTA) with a high heating ramp rate of 100 °C/sec. The perpendicular coercivity (Hc), in-plane coercivity (Hc_//), perpendicular squareness (S) and in-plane squareness (S_//) of the film with no intermediate layer are 8.9 kOe, 9.0 kOe, 0.48 and 0.60, respectively. Its chemical ordering is around 0.82. This degrades to 0.62 and 0.48 respectively when Pt and Pd intermediate layers of 5 nm thick are inserted between the FePt and NiO layers. However, when an Ag intermediate layer with a thickness of 5 nm is introduced, the chemical ordering of the film is further increased to 0.91. Its Hc, Hc_//, S and S_// also increases to 10.2 kOe, 10.6 kOe, 0.62 and 0.68, respectively. The reason for the enhancement in chemical ordering and hard magnetic properties of the FePt film is mainly due to the fact that Ag atoms are immiscible with both Fe and Pt atoms. Instead, Ag tends to segregate at the grain boundary of FePt ; this increases the grain boundary energy, promoting the transformation of soft magnetic fcc FePt into hard magnetic fct L1₀ FePt films.

Abstract: The purpose of this study was to evaluate the physicochemical properties and antimicrobial activity of shellac/2-isopropyl-5-methylphenol composite film patch. 2SHL was applied as a matrix film forming agent for antimicrobial film patch. The samples of IPMP loaded within SHL were prepared in a free film by the casting method. The SHL/IPMP composite film patch was characterized on the physicochemical properties such as: FTIR spectroscopy,X-ray diffraction and mechanical properties. Antimicrobial property was assessed against Staphylococcus aureus and E.coli. The results demonstrated that all films were easily prepared. However, the mechanical properties, XRD and FT-IR of composite film patch were dependent on the composition of blending film while the melting and solubility of film showed no change. The % elongation of the films was increased as the fraction of IPMP increased to 20%, resulting in more flexibility of shellac. The composite film could be formed by the hydrogen bonds, giving the change in physicochemical properties of films. These results were supported by the change in FT-IR and XRD pattern of composite film. The SHL/IPMP composite films exhibited the inhibition zone at 5% concentration of IPMP or more concentration. The diameter of inhibition zone was increased as increasing the percentage of IPMP. The result suggested that antimicrobial SHL/IPMP composite film patch could be achieved. In conclusion, shellac could be a promising polymer for fabrication of antimicrobial film patch, contributing to the widely used as medical products for wound dressing.

Abstract: This article, the preparation and corrosion protection studies of a series of electroactive epoxy titanium dioxide (EET) hybrid materials containing conjugated segments of electroactive amino-capped aniline trimer (ACAT) and titanium dioxide (TiO₂) nanoparticles of ~100 nm in diameter was first presented. It should be noted that EET at higher concentration of TiO₂ was found to reveal better corrosion protection effect as compared to neat electroactive epoxy coating on cold-rolled steel (CRS) electrode based on electrochemical corrosion measurements in 3.5 wt% NaCl electrolyte. Effective enhancement of corrosion protection of EET coatings could be interpreted by electroactive epoxy as a densely physical barrier coating and the redox catalytic capabilities of ACAT units existed in EET may induce the formation of passive metal oxide layers on CRS electrode. Further the well-dispersed TiO₂ nanoparticles in EET matrix could act as effective hinder to enhance the oxygen barrier property of EET.

Abstract: In the present study, the series of PP/SiC composites, containing 5, 10, 15, 20 and 30 wt% of waste SiC particles from abrasive industry, were prepared in order to obtain composites with superior mechanical properties. PP/SiC composites with appropriate amount of SiC were used in order to study the effect of polypropylene-grafted-maleic anhydride (PP-g-MA) as a compatibilizer. PP-g-MA loadings of 0, 1, 3, 5, 7, and 10 wt% were filled composites material by using a two roll mill, extruder and shaped in a hydraulic compression molding machine. Mechanical