Search results for " COMPOSITES"
showing 10 items of 1620 documents
Mechanical Properties of High-Density Polyethylene/Chlorinated Polyethylene Blends
2004
Results of experimental investigation of mechanical properties of high-density polyethylene (HDPE)/chlorinated polyethylene (CPE) blends in tension are reported. The specimens of pure HDPE, CPE, and nine types of HDPE/CPE blends, with different component ratios at 10 wt.% intervals, are examined. The features of the stress-strain curves obtained are discussed. Data on the influence of blend composition on the elastic modulus, yield stress, breaking stress, and ultimate elongation are obtained. The results of investigations into the creep behavior are also presented. It is found that the creep compliance obeys the power law of creep with coefficients depending on blend composition.
Longitudinal Flexure as a Method for Determining the Flexural Strength of Composite Materials
2004
A method is presented for determining the flexural strength of composites from tests on pinned specimens in axial compression. This scheme is close to the so-called Euler buckling model, but the load is applied eccentrically, and the bar is bent practically from the beginning of loading. An analytical model is proposed for calculating the flexural stress in longitudinal flexure of a thin bar in the case of large displacements. The problem is solved in elliptic integrals of the first and second kinds. The analytical model shows an excellent agreement with experiments. The results obtained are compared with experimental tension data. A device is also designed for testing composite bars in lon…
Study and comparison of interaction parameters and phase behavior of epoxy/polystyrene and epoxies copolymer polystyrene-b-poly(methyl methacrylate) …
2008
Thermodynamic studies in terms of phase separation behavior and interaction parameters, in mixtures of epoxy resins (thermoset materials) with thermoplastic additives, consisting of polystyrene (PS) or polystyrene-b-poly(methyl methacrylate) P(S-MMA) (with small proportion of MMA), have been carried out. It can be confirmed that the solubility of P(S-MMA) is an improvement on that of PS, with the prepolymer epoxy resins. Moreover, the interaction parameters are positive at temperatures in which phase separation is observed, but negative at temperatures in which the phase separation window disappears, in the corresponding phase diagram. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engine…
Dislocation interaction with C in α-Fe: a comparison between atomic simulations and elasticity theory
2008
International audience; The interaction of C atoms with a screw and an edge dislocation is modelled at an atomic scale using an empirical Fe-C interatomic potential based on the Embedded Atom Method (EAM) and molecular statics simulations. Results of atomic simulations are compared with predictions of elasticity theory. It is shown that a quantitative agreement can be obtained between both modelling techniques as long as anisotropic elastic calculations are performed and both the dilatation and the tetragonal distortion induced by the C interstitial are considered. Using isotropic elasticity allows to predict the main trends of the interaction and considering only the interstitial dilatatio…
Biodegradation paths of Mater-Bi®/kenaf biodegradable composites
2013
Composites obtained from biodegradable polymers and natural–organic fillers are attracting increasing interest, thanks to the environmental advantages they promise. On the other hand, the real biodegradation performance of a biodegradable polymer/natural organic filler composite should be assessed by performing specific biodegradation tests. These are often carried out under laboratory conditions, but more realistic conditions should be taken into account. In this work, a systematic study on the biodegradation of kenaf fiber-filled Mater-Bi® composites in different environments is presented, and some interesting parameters for the understanding of the optimum way to obtain a fast degradatio…
Matrix and Filler Recycling of Carbon and Glass Fiber-Reinforced Polymer Composites: A Review
2021
Fiber-reinforced polymers (FRPs) are low-density, high-performance composite materials, which find important applications in the automotive, aerospace, and energy industry, to only cite a few. With the increasing concerns about sustainability and environment risks, the problem of the recycling of such complex composite systems has been emerging in politics, industry, and academia. The issue is exacerbated by the increased use of FRPs in the automotive industry and by the expected decommissioning of airplanes and wind turbines amounting to thousands of metric tons of composite materials. Currently, the recycling of FRPs downcycles the entire composite to some form of reinforcement material (…
Modeling the influence of mineral content and porosity on ultrasound parameters in bone by using synthetic phantoms
1999
Model composite media − 10×15×80 mm3 bone tissue phantoms based on an epoxy resin with fillers—were made to study the influence of porosity and mineral content on ultrasound velocity and attenuation. The pores were simulated by ∼ 1 mm3 particles of a soft rubber, while the mineral content was imitated by a mineral residue of natural bone obtained by burning and grinding. The porosity and mineral content were varied in the range of 0–70% by volume with a step of 10%. The velocity, attenuation, and prevalent frequency of ultrasound were measured by the pulse transition method, using transducers with nominal frequencies 0.1, 0.2, 0.5, and 1.0 MHz. It was experimentally found that the ultrasoun…
AN ACCURATE METHOD TO PREDICT THE STRESS CONCENTRATION IN COMPOSITE LAMINATES WITH A CIRCULAR HOLE UNDER TENSILE LOADING
2007
The paper presents a theoretical-numerical hybrid method for determining the stresses distribution in composite laminates containing a circular hole and subjected to uniaxial tensile loading. The method is based upon an appropriate corrective function allowing a simple and rapid evaluation of stress distributions in a generic plate of finite width with a hole based on the theoretical stresses distribution in an infinite plate with the same hole geometry and material. In order to verify the accuracy of the method proposed, various numerical and experimental tests have been performed by considering different laminate lay-ups; in particular, the experimental results have shown that a combined …
Thermal disorder and correlation effects in anti-perovskite-type copper nitride
2017
This work has been supported by the Latvian National Research Program IMIS2. The EXAFS experiment has been financed from the European Community's Seventh Framework Programme under grant agreement No. 226716 (Project I-20100098 EC). J.T. also gratefully acknowledges support from the National Science Foundation under the DMREF program Grant No. CHE-1534184.
Effect of a new amido‐imidazolium compound as a clay modifier on properties of polypropylene composites
2021
Halloysite nanotubes (HNT) and montmorillonite (Mt) were modified by a novel, dicarboxylic fatty acid substituted amido-imidazolium chloride. It was found that the modification process of the clays by the imidazolium compound improved their dispersion in the polymer matrix, while HNT were a more beneficial filler of PP than Mt. PP/imidazolium modified HNT composites (PP/HNT-M) showed significant increase in thermo-oxidative stability, flexibility, and toughness, combined with a slight reduction in stiffness, as well as a lack of changes in crystallinity and strength, compared with neat PP. These effects were not observed for PP/Mt composites. The formation of strong interactions between the…