Physicomechanical Properties Of Composite Materials Research Articles

Improvement of the Mechanical Behavior of Composite Materials with Different Binders Based on Local Plant Fibers Alfa and Diss

Abstract Concerned about the environmental and economic impact, composite materials are increasingly used in the construction sector. Indeed, the use of plant fibers as reinforcement in construction materials have been the subject of several researches in recent years; the main motivation is the weight gain combined with high mechanical characteristics. The objective of this research concerns the study of the physicomechanical properties of composite materials with cement and clay matrices reinforced with Alfa and Diss fibers with dimensions ranging from 2 to 8 cm. This involves evaluating the performance of these materials according to the formulation, for a volume ratio (Alfa or Diss / Matrix fibers equal to 4), using dry fibers and pre-wetted fibers. The study of the mechanical properties showed a drop of the performance for both compression and bending strength compared to the reference material without adding fibers (cement or clay paste). It should be noted that the best mechanical performance is obtained for the case of composites materials with cementitious matrix with pre-wetted fibers. On the other hand, in the case of composites with clayey matrices, pre-wetting does not improve the mechanical characteristics. It is also noted that the best dimensions of fibers which improve the mechanical characteristics in bending are generally 6 cm for composites with a clay matrix and between 2 and 4 cm for cementitious composites. In all cases, the fibers in composite materials with cement or clay matrix create a bridging effect, making it possible to limit the progression of cracks during loading. This phenomenon gives to the various composite materials a ductile behavior.

The Effect of the Strength of Components on the Physicomechanical Properties of Composite Materials

The Effect of the Strength of Components on the Physicomechanical Properties of Composite Materials

Analysis of the effect of the physicomechanical properties of composite materials of carrier layers on the stress state of sandwich shells with rectangular cutouts

A model is described for studying the effect of the physicomechanical characteristics of composite carrier layers on the stress and strain state of sandwich cylindrical shells weakened by rectangular cutouts. The finite element model considered allows us to perform the layer-by-layer analysis of the stress in a wide range of physicomechanical characteristics of the layers. To obtain effective approximations leading to a high convergence rate of numerical solutions and to build the finite element of the carrier layers, the equations of the general sell theory are used. To build the finite element model of the filler, the elasticity theory equations for a three-dimensional body and the carrier layer finite element approximations obtained are applied. The effect of the physicomechanical characteristics of composite carrier layers on the stress and strain state for sandwich cylindrical shells with rectangular cutouts is studied.

Получениe и исследованиe антибактериальных композиционных материалов на основе АБС и олигоэтиленового эфира салициловой кислоты

To give antibacterial properties to ABS-based composite materials, oligoethylene ester of salicylic acid in an amount of 0.5 – 1.0 % was used as additive. It was found that additive practically do not affect the physicomechanical properties of composite materials, but lead to a relative improvement in thermophysical parameters and the appearance of antibacterial properties in them. The antibacterial properties were studied and the possibilities of application of the obtained composite materials were determined. Micromycetes such as Aspergillus niger, A.ochraseus, Penicillium cuclopium, Cladosporium herbarium, Fusarium moniliforme and F.oxysporium were used as a test culture. It was found that the studied composite materials have both bactericidal and fungicidal properties. The fungicidal properties of the obtained new antibacterial composite materials allow their use in the manufacture of products resistant to fungal influence.

Modifying Latex Polymers by Using Highly Dispersed Iron Powder As a Filler

Alkyl (meth)acrylate polymers are synthesized by dispersion polymerization in aqueous media and modified by filling them with highly dispersed iron powder in order to investigate the possibility of enhancing physicomechanical properties of composite materials. The structure of prepared filled polymer materials is investigated and related to their highly elastic properties.

Development of an Epoxy-Polyester Matrix with Improved Adhesive and Physicomechanical Properties with the Use of Isocyanate Modifier

We study the adhesive and physicomechanical properties of composite materials based on the epoxypolyester binders with additions of a methylenediphenyl diisocyanate modifier. It is shown that the matrix with a content of modifier q = 0.25 wt.% is characterized by the highest adhesion and cohesion parameters. The tensile adhesive strength of the epoxy-polyester matrix with improved adhesive properties constitutes σa = 55 MPa, and its residual stresses are σr = 4.1 MPa. The matrix with improved cohesive properties is characterized by the following parameters: its modulus of elasticity in bending E = 3.7 GPa, the fracture stress in bending σst = 57 MPa, and the impact toughness W′ = 8.9 kJ/m2. The fracture surfaces of composite materials are studied by the method of optical microscopy. It is shown that the presence of modifier strongly affects adhesive and cohesive properties of the investigated materials.

Consolidation of Nanocrystals of Detonation Nanodiamond under Thermobaric Sintering

Abstract—The structural and physicomechanical properties of composite materials obtained by sintering detonation nanodiamonds under high pressures and temperatures (P = 5 GPa, T = 1200°C) have been investigated. There is a slight growth of diamond crystals after sintering from 4.5 to 5.2 nm. It is shown that the strength of the samples locally reaches 14 GPa. The high microhardness of the material is due to the consolidation of diamond nanocrystals into strong polycrystalline aggregates owing to the formation of covalent bonds between crystals under high pressure and temperature conditions.

The influence of ultrasound on physico-mechanical properties of composite materials reinforced with carbonaceous fibers in the formation process

The process of reinforcement in the ultrasonic field of structural elements from ABS plastic composite structures containing carbon fibers was studied. The fact of formation of an adhesive-strong interface of “composite-plastic” under the action of ultrasound on the sample during the curing of the composite is established. It is shown that ultrasonic action causes the formation of a homogeneous morphology of the surface and structure of the composite layer, as well as a change in the ratio of the strength parameters of the material. In tensile tests, an increase in strength of 18 % was found with a certain decrease in the elongation.

Influence of fiber loading on physical and mechanical properties of Himalayan nettle fabric reinforced polyester composite

Himalayan nettle plants (Girardinia diversifolia L.) found in the subtropical Himalayan regions, from Kashmir to Sikkim and state of Uttarakhand, at the height between 1200 to 1900 m above sea level. These plants achieve a normal height up to 4-6 m. The fibers extracted from the plant are traditionally used in many applications like ropes; fishing nets; sacking; clothes (scarves, stoles and cushion covers); woven place mates and rugs. This fiber can be utilized as reinforcement in composite materials. In the present work Himalayan nettle fabric reinforced polyester composite materials were prepared in a laboratory by using hand layup technique. The influence of fiber loading (5wt.%, 10wt.%, 15wt.% and 20wt.%) on physico-mechanical properties of composite materials was experimentally investigated as per the ASTM standards. It has been found that the composite panel made of fiber loading of 15 wt.% showed optimum values among all composite samples. The maximum tensile strength (30.69 MPa), impact strength (10.66 Joule) and minimum specific wear rate (0.0199 mm3/Nm) were obtained for composite material with 15wt.% fiber loading. The thermogravimetric analysis (TGA) of the nettle fabric composites suggest that the thermal degradation was occurred in three stages. The major mass losses occur in second stage. The nettle fiber composite is thermally stable beyond 460°C. The results obtained are in consistent with the reported literature.

The Effect of Combined Dispersion of Polyethylene and Carbides on the Structure and Physicomechanical Properties of Composite Materials

The molecular and supermolecular structure and the physicomechanical properties of composite materials obtained by combined dispersion of linear polyethylene and disperse silicon, titanium, and molybdenum carbides on an eccentric vibratory mill were investigated. The correlation between the structure, hardness, softening point, and thermomechanical properties of the composite materials was established.

The Structure and Physicomechanical Properties of Composite Materials Based on Linear Polyethylene and Nanosized Carbides

An investigation was made of the structure at different levels of its organisation and the physicomechanical properties of linear polyethylene under the action of nanosized silicon, titanium, and molybdenum carbides. It was established that the change in the thermomechanical characteristics of the nanocomposites and the increase in hardness and softening point of the materials are due to modification of the molecular and crystal structure of the polymer by nanosized carbides.

Comparative studies on physico-mechanical properties of composite materials of low density polyethylene and raw/calcined kaolin

The paper describes the preparation of the composite materials of low density polyethylene (LDPE) as the base mixed separately with raw kaolin and the same calcined at 800 °C under the same variation in weight percentage using single-screw extruder and a mixing machine operated at a temperature between 190 and 200 °C. Some of the mechanical and physical properties such as Young's modulus, elongation at break, shore hardness and water absorption were determined at different weight fractions of filler (0, 2, 7, 10 and 15%). It was found that the addition of filler increases the mechanical properties. Absorption test was done in water at different immersion times for different composites. The degree of water absorption of composite materials was found to decrease with increasing wt% of kaolin filler (0–15%) according to Fick's law. Calcined kaolin produces better mechanical properties than raw kaolin.

Investigation of Structure and Physico-Mechanical Properties of Composite Materials Based on Copper - Carbon Nanoparticles Powder Systems

Abstract Physico-mechanical and structural properties of electrocontact sintered copper matrix- carbon nanoparticles composite powder materials are presented. Scanning electron microscopy revealed the influence of preliminary mechanical activation of the powder system on distribution of carbon nanoparticles in the metal matrix. Mechanical activation ensures mechanical bonding of nanoparticles to the surface of metal particles, thus giving a possibility for manufacture of a composite with high physico-mechanical properties.

Obtaining Some Polymer Composites Filled with Rice Husks Ash-A Review

Rice husks are an important by-product of rice milling process and are major waste product of the agricultural industry. Rice husk contain nearly 20 mass% silica, which is present in hydrated amorphous form. They have now become a great source as a raw biomass material for manufacturing of value-added silicon composite products, including silicon carbide, silicon nitride, silicon tetrachloride, magnesium silicide, pure silicon, zeolite, fillers of rubber and plastic composites, cement, adsorbent and support of heterogeneous catalysts. The rice husk was subjected to pyrolysis in fluidized-bed pilot plant in air or nitrogen atmosphere. The controlled thermal degradation of the rice husks in air or nitrogen leads to production of white rice husks ash (WRHA) and black rice husks ash (BRHA) respectively. WRHA contains almost pure (³95mass %) silica in a hydrated amorphous form, similar to silica gel, with high porosity and reactive surface OH groups. BRHA contains different amounts of carbon and silica in amorphous form with high specific surface area and porosity. The raw rice husks and the obtained pyrolysis products were used as fillers of polypropylene (PP) and tetrafluoroethylene-ethylene copolymer (TFE-E) composites. The kinetics and thermodynamics of water adsorption onto filled polypropylene composites during soaking were studied at different temperatures, quantities and nature of fillers. It was established, that the adsorption kinetics was limited by intra-particle diffusion in plane sheet particles. The sorption process is exothermal in nature and accompanied with decrease of the entropy. The physicomechanical properties of composite materials were determined. The fillers introduced in polypropylene change the mechanical strength and make the composites brittle. This change is more pronounced for the composites with BRHA and RRH, followed by WRHA. The composites studied showed lower elongation at break. The biggest decrease was observed for the composites with BRHA where ? decrease from 500 (for the initial PP) to 7 % at filling degree of 20 mass %. The effects of the amount of adsorbed water, temperature and treatment time on the composites tensile properties were estimated. It was found after immersion in water that the composites improve their tensile strength compared to initial non-treated samples. The thermal stability and kinetics of non-isothermal degradation of PP and TFE-E composites filled with 10 or 20 mass % vigorously grounded and mixed RRH, BRHA, WRHA and Aerosil Degussa (AR) were studied. Using different calculation procedures the most probably kinetic mechanism was found to be described by kinetic equations of n-th order (Fn mechanism). The kinetic parameters were obtained, and a linear dependence between ln A and E was observed, known also as kinetic compensation effect. The abundance of a waste from paddy milling industry, as well as its interesting complex of behaviors are prerequisite for success for obtaining of cheap and valuable products and gives a new alternatives for its applications. The production of value added materials from rice husks not only facilitates utilization of an abundantly available agro waste, but also reduces the environmental pollution and solves a serious ecological problem.

Highly wear-resistant composites based on copper powder mixture with onion carbon nanostructures for self-lubricating friction units

The problem of using onion carbon structures in the development of highly wear-resistant powder composite materials on a copper matrix base is discussed. Study results are presented of the triboengineering and physicomechanical properties of composite materials with a nanostructured filler. Reduction of the wear rate of the composites with copper and onion carbon nanostructures is attributed to decreased metal contact area on the friction surface and inhibited seizure.

Influence of climatic operational conditions of a helicopter on physico-mechanical properties of composite materials

The results of numerical and experimental study of physico-mechanical properties of composite materials are proposed and variations in rigidity characteristics of the hub working part of the hingeless type within the entire range of helicopter operational temperatures are evaluated.

Structure and high-temperature strength of composite materials based on boron nitride

The structure and physicomechanical properties of composite materials based on boron nitride within which new phases (mullite and sialon) form during hot compaction are studied. It is established that the microstructure of composites is specified by their texture formation caused by the crystal morphology of boron nitride particles and it is almost independent of composite phase composition. It is shown that the main factor that affects strength is porosity. The dependence of strength on porosity is exponential in character. The strength of boron nitride-mullite and boron nitride-sialon composites is 110–140 MPa and at 20–1200°C it is almost unchanged.