Fillers In Polymer Matrix Research Articles

Improved performance of PDMS/ceramic composite pervaporation membranes by ZSM-5 homogeneously dispersed in PDMS via a surface graft/coating approach

A homogeneous dispersion of inorganic fillers in polymer matrix is a primary challenge for the advancement of mixed matrix membranes (MMMs) in pervaporation and gas separation. In this work, a surface graft/coating approach was developed for homogeneously dispersing ZSM-5 zeolite in polydimethylsiloxane (PDMS) for preparing ZSM-5 filled PDMS mixed matrix/ceramic composite membranes. Molecular dynamics simulations were carried out to calculate the interaction energy between zeolite and PDMS. It was found that surface modification of zeolite particles could highly improve their interaction with PDMS matrix. The SEM images confirmed the uniform dispersions of surface-modified ZSM-5 particles in PDMS matrix even at highest zeolite loading of 40 wt.%. As revealed in the FT-IR analysis and contact angle measurements, the prepared ZSM-5 filled PDMS membranes exhibited less hydroxyl groups and became more hydrophobic with increasing zeolite loading. The pervaporation experiment in 5 wt.% ethanol–water solution indicated that the homogeneously incorporated ZSM-5 particles improved the selectivity of PDMS membrane, and the separation factor of surface-modified ZSM-5 filled PDMS membrane increased gradually with zeolite loading. This effective dispersion method could be instructive for the fabrication of organic–inorganic composite materials.

Preparation and properties of environmental friendly nonhalogen flame retardant melamine cyanurate/nylon 66 composites

AbstractMelamine cyanurate (MCA) was utilized as an environmental friendly additive to prepare the nonhalogen flame retardant MCA/Nylon 66 composites by melt blending technique. Because of the strong hydrogen bond interactions and fine interfacial compatibility between MCA and Nylon 66, the resultant even dispersion of MCA filler in polymer matrix leads to the better toughness and strength of MCA/Nylon 66 composites than those of neat Nylon 66. Both Nylon 66 and MCA/Nylon 66 composites exhibit similar α‐crystalline structure, but the presence of MCA influences the distribution of α1 and α2 crystalline phases in Nylon 66 by inducing its hydrogen‐bonded sheet separation. Moreover, the blending of MCA and Nylon 66 increases the crystallization temperature and exothermicity but decreases the thermal stability of Nylon 66 and accelerates the degradation of MCA. The MCA/Nylon 66 composites show better flame retardancy at intermediate MCA contents of 10 and 15 wt %. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Characterization of Ceramic Filled Polymer Matrix Composite Used for Biomedical Applications

A particulate composite material was prepared by adding (CaCO3, CaO, MgCO3, MgO) ceramic particles with particle size of (< 53 μm) to unsaturated polyester resin with weight fraction of (3, 6, 9, 12, 15)% and fixed amount of CaF2 (0.5% wt.). The results had revealed that the maximum values of tensile strength, compression, bending strength, hardness, impact energy and water absorption%, were (57.6828 N/mm2 at 3% wt. CaCO3, 124.0965 N/mm2 at 9% wt. CaCO3, 102.188 N/mm2 at 9% wt. MgO, 88.2 Shore D at 9% wt. CaCO3, 0.27 J at 6%wt. CaCO3 and 0.8432 % at 15%wt.CaO) compared with reference values, i.e.( 37.4742 N/mm2, 100.3563 N/mm2, 34.194 N/mm2, 83 Shore D, 0.36 J and 0.2626%) respectively.

Preparation and Characterization of Hybrid Membranes based on Nafion (R) using Partially Sulfonated Inorganic Fillers

This work reports the preparation and characterization of inorganic hybrid membranes cast from solutions of perflouorinated sulfocationic ionomers (Nafion® 117) containing 10 wt % dispersed inorganic fillers. Silica gel, SBA-15 and sepiolite, all of them partially functionalized with sulfonic acid groups, were used as fillers. Fillers slightly reduce the water uptake without altering the ion-exchange capacity of the membrane composites. FTIR and DMTA analysis techniques suggest that filler-polymer matrix interactions are stronger with sepiolite than with the other fillers. The fillers used enhance the mechanical properties of the membranes, but they negatively affect the thermal stability of the composites. The permeability coefficient of oxygen in Nafion® and Nafion®-sepolite membranes is similar, and it is slightly lower in the others. The conductivity of the hybrid membranes equilibrated with water, measured at 80o C by impedance spectroscopy, is 4.0, 6.0 and 6.3 S/m for the hybrid membranes containing functionalized Silica gel, SBA-15 and Sepiolite fillers, respectively, somewhat lower than that found for the Nafion® 117 membrane, 5.9 S/m, measured in the same conditions.

Modification of the Dynamic Damping Behavior of Fly Ash Filled Unsaturated Polyester Resin/SBR Latex Blend Composites

An attempt has been made to develop fly ash filled polymer matrix composites with high damping behavior. Fly ash filled polymer matrix composites do not show very high damping property and this limits their application in many fields. Hence, unsaturated polyester resin (UPE) was blended with SBR latex in three proportions and this blend was used as the matrix for making the composites. Both 40 and 50 wt% fly ash loaded blend matrix composites were prepared by the room temperature casting method. Flexural properties were investigated. The damping behaviors of the composites were determined by dynamic mechanical analysis (DMA). The presence of latex particles significantly enhanced the damping property. The combination of damping behavior with good mechanical property was optimized. UPE resin blended with 5wt% SBR latex was found to have good strength with enhanced damping property. Very high damping can be achieved with the UPE/10 wt% SBR latex blend matrix having 50 wt% fly ash loading. The fracture surfaces examined under SEM revealed good compatibility between the various components of the systems.

BCB Resin-BNT 복합 기판 소재의 제조 및 특성 평가

BCB Resin-BaNd₂Ti₄O₁₂(BNT) composites with BNT contents were prepared by tape casting method and epoxy resin-BNT composites were prepared by using heating press. Their dielectric properties and microstructures were investigated. The dielectric properties such as dielectric constant and dielectric loss at 1㎒ for epoxy resin-BNT composites and BCB resin-BNT composites are improved with an increase of BNT volume fraction. The dielectric constant of the Epoxy-BNT composite increased from 5.9 to 7.8 as the volume fraction of BNT increased from 15 to 25. The dielectric constant of the BCB-BNT composite increased from 9.1 to 15.5 as the volume fraction of BNT increased from 30 to 50. The dielectric behavior of BCB-BNT system can be explained by Lichtenecker’s equation. The dielectric constant of epoxy resin-BNT composite is smaller than that of BCB resin-BNT composite. These results are considered to be related with the dispersion of BNT filler in polymer matrix from the result of SEM photograph.

Preparation and characterization of a double filler polymeric nanocomposite

Single walled carbon nanotubes (SWNTs) with an anisotropic morphology (rod) are currently being employed as fillers in polymer matrix to produce novel nanocomposites with enhanced properties and performance in a wide variety of applications. We investigate the effect of the addition of second isotropic (spherical) filler, antimony tin oxide (ATO) particles to the anisotropic SWNT-polymer composites. Cryogenic transmission electron microscope (cryo-TEM) and scanning electron microscope (SEM) were employed to image the aqueous dispersions of the SWNTs–ATO–Latex solution and composite thin films respectively. The SEM imaging of these films shows that SWNTs (rods) tend to aggregate in the presence of ATO clusters, indicating depletion interactions between the rods and the spheres. The difference in the value of electrical conductivity of the films measured along the radial and the tangential directions to the spinning lines is probably due to the preferred orientation of the SWNTs in the matrix during the spin coating process.

A thermodynamics based damage mechanics model for particulate composites

A micro-mechanical damage model is proposed to predict the overall viscoplastic behavior and damage evolution in a particle filled polymer matrix composite. Particulate composite consists of polymer matrix, particle fillers, and an interfacial transition interphase around the filler particles. Yet the composite is treated as a two distinct phase material, namely the matrix and the equivalent particle-interface assembly. The CTE mismatch between the matrix and the filler particles is introduced into the model. A damage evolution function based on irreversible thermodynamics is also introduced into the constitutive model to describe the degradation of the composite. The efficient general return-mapping algorithm is exploited to implement the proposed unified damage coupled viscoplastic model into finite element formulation. Furthermore, the model predictions for uniaxial loading conditions are compared with the experimental data.

Modeling of ceramic particles filled polymer–matrix nanocomposites

In this work, the mechanical properties of polymer matrix–ceramic fillers nanocomposites were investigated. A PCL (poly-caprolactone) matrix was reinforced with increasing amount of nano-sized silica particles in the range 1–2.5% by weight, and the resulting properties were determined as a function of reinforcement characteristics and volume fraction. In order to gain a deeper insight into the mechanical behaviour of such nanocomposites, a numerical model able to reproduce the peculiar composite features was set up. The study focussed on the effect of particles size and amount on the achieved increment in the overall stiffness. The computational approach revealed that a third phase, namely the interphase, has to be taken into account in the model in order to accurately reproduce the experimental results.

Poly(ethylene terephthalate)(PET) nanocomposites filled with fumed silicas by melt compounding

PET nanocomposites filled with fumed silicas were prepared via direct melt compounding method at various mixing conditions such as filler type and filler content. Some fumed silicas were pre-treated to improve the wettability and dispersibility, and principal characterizations were performed to investigate the effects of nano fumed silicas on polymer matrix. Hydrophobic fumed silica (M-FS), which has the similar contact angles of water with neat PET, acted as the best reinforcement for the thermal stability and mechanical properties of PET nanocomposite, and FE-SEM images also showed that M-FS was uniformly dispersed into matrix and had good wettability. But, some filler (O-FS) had low dispersibility and caused the deterioration of mechanical properties. Besides, the results of DSC revealed the nucleation effect of all fillers in polymer matrix, and PET nanocomposite filled with hydrophilic fumed silica (FS) showed markedly the characteristic dynamic rheological properties such as shear thinning behavior at very low frequencies and the decrease of viscosity.

Determining influence of the phase interface on the properties of compositions of phenylone with element-carbon fibers

Interphase processes in the compositions of aromatic polyamide phenylone with element-carbon fibers are studied. Significant differences in the structure and properties of polyamide discretely reinforced with metal-carbon fibers and carbon fibers with functional groups are revealed. It is found that the observed changes are mainly due to the physicochemical interaction on the interface “fibrous filler-polymer matrix” during formation of the composition.

Physical aging in the creep behavior of thermosetting and thermoplastic composites

The creep behavior of a series of fiber-reinforced plastics (FRP) and corresponding resins has been studied, with emphasis on elucidating the role of physical aging effects on FRP viscoelastic behavior. Thermosetting and thermoplastic composites were studied, representing semicrystalline, amorphous, and highly filled amorphous polymer matrix FRPs. It was found that physical aging effects are operative for all FRPs, including the semicrystalline systems. Time/ aging-time and time/temperature superposition are found to be valid procedures for short-term creep behaviour; they cannot be applied to long-term creep behavior. However, long-term creep can be satisfactorily predicted from momentary creep by using an effective time theory. Evidence of a universal, temperature shift factor temperature dependence is presented.