Types Of Polymer Composites Research Articles

Dielectric Properties of Three Perovskite Oxides Included in Three Types of Polymer Composites

Dielectric Properties of Three Perovskite Oxides Included in Three Types of Polymer Composites

STUDYING SOME OF PHYSICAL PROPERTIES FOR POLYMER REINFORCED WITH CHOPPED CARBON FIBERS (CCF) COMPOSITES

The research includes the study of some physical. Properties (thermal conductive and dielectric strength) for two types of polymer composites; epoxy resin (EP) reinforced by chopped carbon fibers (CCF) and unsaturated polyester resin (UPE) reinforced by chopped carbon fibers at different weight percentage (1%, 3%, 5%, 7%). Hand –lay up. Method was used to prepare sheets of composites (EP, UPE, EP/CCF, and UPE/CCF) on. glass mold which were cut according to the standard dimensions of the thermal conductive and dielectric strength tests specimens. The results showed that the. Sample of UPE/CCF have highest values of thermal conductive at weight. percentage (7%) compared with prepared samples at other weight percentage. Also the results showed that the thermal conductive of. Pure UPE and EP increased with increase in weight percentage of carbon fibers addition. On the other hand, the results showed that the polyester composites have higher values of thermal conductive compared with epoxy composites. Also the results showed that higher value of dielectric strength at weight. Percentage (1%) for both types from prepared composites of carbon fibers.In addition, the results showed that the polyester composites have higher values of dielectric strength compared with epoxy composites.

The Influence of the Use of Technological Waste and the Simulation of Material Lifetime on the Unnotched Impact Strength of Two Different Polymer Composites

The article deals with the assessment of the impact of technological polymer waste resulting from plastic injection technology and the subsequent simulation of the lifetime of polymer products on the impact strength of two different polymer composites. Two different types of polymer composites used to produce plastic parts in the automotive industry were chosen for the research. Based on the evaluation of the PBT composite before exposing the specimens to elevated temperature, it can be concluded that the concentration of the recycled material in the virgin material only affects the values of the unnotched impact strength of the PBT composite when the recycled material accounts for at least 50 wt.%. The results of the unnotched impact strength of the test specimens exposed at 150 °C/500 h make it evident that the addition of recycled material to the virgin material significantly reduces the components' service lives. The same trend could be observed with the second tested composite material, PPA.

Enhancement of soil ecological self-repair using a polymer composite material

The surface soil of newly cut slopes used in ecological protection engineering has a loose structure, low strength, and an inadequate water amount and moisture conservation capacity. This results in weak vegetation growth, negative long-term effects, and high maintenance costs. For this reason, a novel type of polymer composite, namely, an aqua-dispersing-nano-binder (ADNB), optimised using different ratios of polymer adhesive and resin, was used to carry out water retention, erosion, and plant growth tests on weathered silty clay in the red beds of southern China. In addition, ADNB soil treatments were compared with untreated soil, and the occurrence and mechanism of water retention and erosion resistance in ADNB-modified soil were determined. The results show that with an increase in the amount of resin, the dry density of the soil decreased, and the void ratio, field capacity, and water holding capacity increased. With an increase in the amount of applied polymer adhesive, the dry density of the soil increased, and the void ratio, field capacity, and water holding capacity decreased, but were higher than those of the untreated soil. The mechanism of the ADNB modifying soil structure and improvements in its ecological self-repair were analysed. The adsorption and storage of free water by resin in the soil was observed through NMR imaging. Adding ADNB material at an appropriate proportion to the soil not only enhances the soil strength and erosion resistance, but also increases the soil water holding capacity and promotes plant growth. Thus, the ecological self-repair of the soil and the ecological protection of the slope can be significantly improved.

Single Edge Notch Bend (SENB) of Kenaf/Fibreglass Hybrid Composites

Kenaf is known for many years as a typical crop that can be used in various applications such as in automotive, and building structure. Along with the depletion and environmental issues raised nowadays by excessively used of man-made synthetic fibres make the natural fibre to become popular and favourable to be implemented. This paper discusses on the development of long kenaf fibre reinforced polyester matrix composite. Total weight of about 40% fibre fraction was selected. In this study, the addition of about 10% weight fraction of fibreglass in the composite system is needed in order to strengthen the composite material and also to retain its reliability and robustness in their applications. Thus, preparation of two different layer arrangement of kenaf and fibreglass were conducted viz. (i) kenaf at inner layer and fibreglass at outer layer ([0o90o]K/FG2p/[90o0o]k[0o90o]K) (ii) kenaf at outer layer and fibreglass at inner layer (FG/[0o90o/90o0o]K/FG). All configuration samples were fabricated by hand lay-up and cold press technique. Fracture toughness testing was carried out using a single edge notched bend specimen at a loading rate of 10mm/min. All samples were prepared according to ASTM D5045 (Standard Test Methods for Plane-Strain Fracture Toughness and Strain Energy Release Rate of Plastic Materials). Results obtained from SENB test were then evaluated and discussed. It can be used as a guideline or reference for further research on this type of polymer composite.

Recent Research Status on Polymer Composite Used in Concrete-An Overview

Abstract To being with research work it is necessary to get aware with previous research work carried out in the relevant domain. Therefore, this overview is intended to put forward various types of polymer composites used in concrete for experimental work carried out by researchers. Also, to explore the effect of various components use to prepare polymer concrete like types and content of resin, filler, additive and effect of temperature on fresh and hardened properties of polymer concrete. Finally, some inferences drown from an overview and concludes some future scope that will helpful for new researchers in the field of polymer composites to use polymers in concrete.

Comparison of Dynamic Mechanical Properties and Thermal Conductivity of Unsaturated Polyester Composites Filled With Plain SiO2 Aerogel and Core-Shell SiO2 Aerogel

Abstract An unsaturated polyester resin was modified with plain and core-shell SiO2 aerogels having mean particles diameter of 2.5±0.5 mm. The core-shell structured particle consists of nanoporous SiO2 aerogel core and polyvinyl alcohol shell fabricated using fluidized bed coating process. Two types of polymer composites were prepared at a 30% (by volume) of plain and core-shell aerogels and the thermal conductivities and viscoelastic behaviors of the composites were compared using hot-disk thermal analyzer and dynamic mechanical analysis. The results in this work reveal better thermal insulation and dynamic mechanical properties of the composite containing core-shell aerogels due to preserved aerogel pores and better filler-matrix interaction.

Dielectric relaxation of near-percolated carbon nanofiber polypropylene composites

In this work, the morphological, structural and dielectric analysis of near-percolated polypropylene (PP) composites containing carbon nanofibers (CNF) processing by melt-mixing are investigated. Whereas the morphological analysis shows that CNF exhibit some tendency to agglomerate within the PP matrix, the structural analysis showed first a general decrease in the intensity of the IR bands as a consequence of the interaction between carbon nanofibers and PP matrix and second an increase of the crystallinity degree of the PP/CNF composites when compared to the pure PP. The dielectric analysis demonstrates enhanced dielectric constants (from 2.97 for neat polymer to 9.7 for 1.9vol% loaded composites at 200Hz) and low dielectric losses. Furthermore, the dielectric relaxation for composites with concentrations in the vicinity of percolation is evidenced and well described by the generalized polydispersive Cole-Cole model from which the values of static dielectric constant (εs), high frequency dielectric constant (ε∞), distribution of relaxation time (α) and mean relaxation time (τo), are determined, suggesting that this latter analysis constitutes a strong tool for understanding the relationships between microstructure and dielectric properties in this type of polymer composites.

Free Vibration Test for Damping Characteristics of Hybrid Polyester Matrix Composite with Carbon Particles

In this research aims to study the damping characteristics of hybrid polymer composite, which can be used in engineering structures and in many other applications. Hybrid composites are namely Glass fiber and carbon filler reinforced with polyester and epoxy matrix have been prepared by vacuum bag molding fabrication technique. Then the free vibration test were conducted using FFT analyzer with Lab VIEW software. The damping ratio and natural frequency were investigated for fabricated composites. Then through ANSYS, the mode shapes and natural frequencies were determined and the results were compared with experimental results. The damping ratio increases with increased volume fractions of E-glass fibers for both the types of polymer composites. Vibrations are concerned to large structures such as aircraft, as well as small structures such as electronic equipments.

Synthesis and characterization of high density polyethylene/peat ash composites

Abstract A new type of polymer composite was synthesized from peat ash which was obtained as industrial waste. This was added to high density polyethylene (HDPE) at varying mixing ratios and the resulting products were characterized using different experiments which included Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), melt flow index (MFI), density, wettability, tensile test, flexural test and cost analysis. The effects of various ash loadings and the use of the maleic anhydride grafted high density polyethylene (HDPE-g-MA) compatibilizer on the physical and mechanical properties of composites were investigated. It was observed that the utilization of peat ash significantly increased the tensile strength and the flexural modulus, where also reducing raw material cost. Incorporating (HDPE-g-MA) in the composites formulation led to further increases in tensile and flexural properties. Conversely, there was a significant decrease of impact strength found for all composites in comparison to the virgin HDPE. And the impact strengths generally decreased as peat ash content increases. Microstructural analyses showed that surface treated peat ash particles appeared to be well-incorporated into the HDPE matrix, as intimated polymer/peat ash contact was observed. In addition, the melt flow index of the composites decreased remarkably with an increase in peat ash content. No significant water uptake effect was detected on peat ash composites indicating that these materials could be used as a direct replacement for HDPE in applications where impact strength is not a critical factor. Furthermore, the use of peat ash increased the composite density in comparison to virgin HDPE. Nevertheless, as peat ash reinforcement does offer increased tensile and flexural properties, this may make the end product lighter as lower wall thickness parts can be used to fulfil the same function. From this study, it was concluded that the utilization of the peat ash from peat fired power stations has proved to have significant value-added potential as a filler material in polymer composites.

Is the use of correct terms and definitions important in creation of new materials?

and widely applied term is a case in composite community, where the thermodynamic term ‘phase’ is used instead of the term ‘component’. Obviously, the misuse of the term ‘phase’ is a remnant from the time when the colloid chemistry was formulated (second half of 19th century, i.e. long before the polymer science was defined). The confusion of this misuse can be easily demonstrated by poly(vinylidene fluoride) (PVDF) exhibiting five crystalline polymorphic modifications (phases!) and one amorphous phase but PVDF is still a one-component system. While this example does not have a direct effect on the creation of new materials, the next one, the definition of the relatively new type of polymer composites, the single polymer composites (SPCs), does. SPCs have also been called: one polymer composites (R. Porter), homocomposites, self-reinforced composites, one-phase composites, homogeneous composites, or all-polymer composites. The concept of SPCs has been formulated by R. Porter some 40 years ago (DOI: 10.1007/BF00554928) as attempt to solve the basic problem in polymer science and technology, namely, the low adhesion quality between matrix and reinforcement due to their different chemical composition. The approach is quite simple – the matrix and the reinforcement have to be of the same polymer, i.e. to be chemically identical. The idea attracted the attention of academia and industry during the last decade when patents were registered and products were commercialized; nanofibrillar SPCs with superior mechanical properties were also created (DOI: 10.1002/mame.201200226). What is more, similar products were prepared and called also SPCs (DOIs: 10.1007/s10853-009-3792-1, and 10.1016/j.compscitech.2013.12.006) using highly oriented poly propylene (PP) (as reinforcement) and the random copolymer of PP (usually with polyethylene) as a matrix thus neglecting the basic requirement (R. Porter) for identical chemical composition of matrix and reinforcement. Strictly speaking, such composites belong to the category of polymer–polymer composites. The same holds for thermoplastic copolyesters reinforced with ‘homo’-poly(ethylene terephthalate). The argument that the two chemically different components belong to the same polymer family (DOI: 10.1016/j.compscitech.2013.12.006) could hardly be seriously considered – it only smears the boundary between the two types of composites, the polymer-polymer ones and the SPCs and makes the clear definition of single polymer composites hardly possible affecting in this way negatively their further development! In order to make use of the unique properties of SPCs we should not forget that they could be multi-phase but always remain one-component systems!

Synthesis of SBA-16 Supported Catalyst for CNTs and Dispersion Study of CNTs in Polypyrrole Composite

ABSTRACTIn last two decades, huge amount of research work has been contributed in the field of nanochemistry particularly for synthesis, characterization and applications of carbon nanotubes (CNTs). For synthesis of CNTs through chemical vapor deposition (CVD), supported metal catalyst is used preferentially. In view of that, SBA-16 supported nanoprticles of Iron, Fe/SBA-16, were prepared. To have Fe/SBA-16, adsorption of Fe nanoparticles on SBA-16 have been accomplished by reduction of ferrous ion on the surface of SBA-16. Afterwards, CNTs were synthesized by CVD using benzene as precursor over Fe/SBA-16 nanocatalyst. Synthesis of CNTs was carried out at 750°C with ambient pressure. Synthesized CNTs were functionalized by treating the them with a mixture of H2SO4/HNO3. As a result of this acidic treatment, carboxylic functional group was introduced on the surface of CNTs due to oxidation. As such prepared and functionalized CNTs were, further, used as filler in the synthesis of polymer nanocomposites of polypyrrol(PPY), matrix. These nanocomposites were prepared by in situ polymerization. Thus, electrical conductivity is measured for both types of polymer composites. On their comparison, important information regarding dispersion of CNT in the matrix are extracted.

Synthesis and characterization of C60 -based composites of amphiphilic N -vinylpyrrolidone/triethylene glycol dimethacrylate copolymers

It was found that under mixing of aqueous solutions of copolymers and toluene solutions of C60 two types of polymer composites can be produced with different matrix structure, the fullerene content and an aggregation degree. The dimethacrylate enriched macromolecules migrate to toluene and the VP units enriched copolymer chains remain in water to form copolymer micelles and their aggregates in these media that solubilize and encapsulate the fullerene. The structure and properties of obtained polymer composites were studied by GPC with dual detection (RI and MALLS), FT-IR, WAXS and SAXS methods. It is shown that in a composite based on N-vinylpyrrolidone copolymer isolated from toluene the fullerene form larger particles, compare to that isolated from water. According to SAXS, the fullerene particles in a solid copolymer are organized in spherical objects with fine coil-like structure. The stability of the composites in water, ethanol, and chloroform was shown to depend on the original polymer matrix structure and on copolymer/fullerene ratio. POLYM. COMPOS., 35:1362–1371, 2014. V C 2013 Society of Plastics Engineers

Specific erosive wear rate of neat polymer films and various polymer composites

The behavior of unidirectional carbon fiber-reinforced polyetheretherketone composites was studied under solid particle erosion, using different impact conditions and erodents. The data were analyzed on the basis of a newly defined specific erosive wear rate, allowing a better comparison of erosion data achieved under various testing conditions. Characteristic wear mechanisms of the carbon fiber/polyetheretherketone composites consisted of fiber fracture, matrix cutting and plastic matrix deformation, the relative contribution of which depended on the impingement angles and the carbon fiber orientation. The highest wear rates were measured for impingement angles between 45 and 60°. Another type of polymer composites, the so-called microfibrillar composites, which consisted of polyethyleneterephthalate fibrils in a high-density polyethylene matrix, exhibited a maximum erosion rate in the range of 30° to 45°, i.e. closer to that typical for the erosion of ductile polymers. The absolute values for the microfibrillar composites were, however, higher than those measured for the neat high-density polyethylene matrix. Using abrasion-resistant polymer films (in this case polyetheretherketone or thermoplastic polyurethane ones) on the surface of a harder substrate (e.g. a carbon fiber/polyetheretherketone composite plate) resulted in much lower specific erosive wear rates. The use of such polymeric films can be considered as a possible method to protect composite surfaces from damage caused by minor impacts and erosion. In fact, they are nowadays already successfully applied as protections for wind energy rotor blades.

Preparation and structural evaluation of nano reinforced composites from cellulose whiskers of grass and biodegradable polymer matrix

Biocomposites of polylactic acid with cellulose whiskers from grass were prepared and reinforced with nanolayer-filled ionomer (Surlyn®). Three types of polymer composites were fabricated by filling the whiskers in polylactic acid at 5, 10, and 15% concentration. The analysis of resulting products was conducted by monitoring the functional group variation, crystallinity, and thermal behavior. The addition of clay-filled ionomer appeared to enhance the interfacial adhesion between filler and matrix by chemical and physical bonding. The migration tendency of different components inside silicate layers was also studied where the confinement of host polymer chains occurred between clay platelets, after modification through ionomer.

A percolation model for carbon nanotube-polymer composites using the Mandelbrot-Given curve

A model is introduced for the conductivity of carbon-nanotube polymer composites based upon percolation theory and fractals. These types of polymer composites have been developed in the recent years, and experimental data on their percolation threshold is available. We constructed a fractal space with the aim of the generalized Mandelbrot-Given curve and used the experimental critical exponent of conductivity to calculate the parameters of such a curve. Finally, the moments of the current distribution function are estimated, and the effect of the critical exponent on this function is investigated.

INNOVATIVE MANUFACTURING OF CARBON NANOTUBE-LOADED FIBRILLAR POLYMER COMPOSITES

The concept of microfibrillar composite (MFC) has been used to create a new type of polymer composites, in which the reinforcing microfibrils are loaded with carbon nanotubes (CNT). Polyamide 66 (PA66) has been melt blended with polypropylene in a twin screw extruder with and without CNT, and thereafter cold drawn to create a fibrillar state as well as to align the CNT in the PA66 microfibrils. The drawn bristles were compression moulded at 180°C to prepare MFC plates. The scanning electron microscope (SEM) observations indicate near perfect distribution of CNT in the reinforcing PA66 microfibrils. Although the fibrillated PA66 is able to improve the tensile stiffness and strength as expected from the MFC structure, the incorporation of CNT does not exhibit any further enhancing effect. It rather adversely affects the mechanical properties due to poor interface adhesion between the matrix and the reinforcing microfibrils with the presence of CNT, as demonstrated by SEM. However, the resulting highly aligned CNT within the MFC are expected to affect the physical and functional properties of these composites.

Stiffness analysis of polymeric composites using the finite element method

The ability to predict the mechanical behavior of polymer composites is crucial for their design and manufacture. Extensive studies based on both macro- and micromechanical analyses are used to develop new insights into the behavior of composites. In this respect, finite element modeling has proved to be a particularly powerful tool. In this article, we present a Galerkin scheme in conjunction with the penalty method for elasticity analyses of different types of polymer composites. In this scheme, the application of Green's theorem to the model equation results in the appearance of interfacial flux terms along the boundary between the filler and polymer matrix. It is shown that for some types of composites these terms significantly affect the stress transfer between polymer and fillers. Thus, inclusion of these terms in the working equations of the scheme preserves the accuracy of the model predictions. The model is used to predict the most important bulk property of different types of composites. Composites filled with rigid or soft particles, and composites reinforced with short or continuous fibers are investigated. For each case, the results are compared with the available experimental results and data obtained from other models reported in the literature. Effects of assumptions made in the development of the model and the selection of the prescribed boundary conditions are discussed. © 2001 John Wiley & Sons, Inc. Adv Polym Techn 20: 42–57, 2001

Moisture-absorption, dielectric relaxation, and thermal conductivity studies of polymer composites

In the search for new packaging materials for the electrical/electronics industry, three types of polymer composites have been studied. Silicone/boron nitride powders, polyurethane/alumina powders, and polyurethane/carbon fibers have all been synthesized to study the moisture–absorption kinetics, thermal conductivities, and the dielectric loss spectra under various levels of humidity. The water uptake data indicate that water molecules are absorbed not only by the polymer matrix, but also by the interfaces introduced by the fillers. For all materials, the dielectric relaxation spectroscopy shows the presence of a peak in the 175–200 K range, which is largely due to absorbed water. The silicone/boron nitride samples absorbed the least amount of moisture. Incorporating this result with the thermal conductivity data of the three types of polymer composites, it is concluded that silicone polymers embedded with boron nitride can best serve as the coating for the electronic devices that require heat dissipation and moisture resistance, in addition to electrical insulation. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2259–2265, 1998

Thin films of organic polymer composites with inorganic aerogels as dielectric materials: polymer chain orientation and properties

High temperature poly(p-phenylene biphenyltetracarboximide) nanocomposite films with inorganic particulates, which are applicable to the fabrication of microelectronic devices, were prepared from the poly(amic acid) and silica aerogels with a size of ca. 150 nm in diameter by solution blending and subsequent conventional polyimide film formation process. The structure and properties were measured. By the composite formation, the optical and dielectric properties were improved due to the low dielectric constant characteristic of silica aerogels, whereas the interfacial stress and thermal expansion coefficient were significantly degraded by a large disturbance in the polymer chain in-plane orientation caused by silica aerogels despite of their low thermal expansivity. This indicates that in the rigid type of polymer composites with inorganic particulates, the orientation of polymer chains still plays a critical role on the physical properties.