Poly Methyl Methacrylate Composites Research Articles

The interlaminar shear strength and impact performance of polytetrafluoroethylene fiber-reinforced polymethyl methacrylate composites filled with silicon dioxide

The interlaminar shear strength (ILSS) of polytetrafluoroethylene (PTFE) fiber-reinforced polymethyl methacrylate (PMMA) composites enhanced by filled silicon dioxide (SiO2) is studied. The PMMA blends were prepared by combining the techniques of high-speed mechanical stirring. Experimental results showed that ILSS and impact properties of PMMA composites were improved. The largest improvement in ILSS and impact strength were obtained with 7 vol % loading of SiO2. ILSS and impact strength were improved by 15 and 50%, respectively, compared with the composite without SiO2. The fracture and surface morphologies of the composite specimens were characterized using scanning electron microscopy. This PTFE fiber-reinforced composite can be applied to bioengineering and fabrics.

The Improvement of Dental Composite Properties with Electromagnetically Aligned Nanofiber

ABSTRACTBecause of the aesthetics, handy and low cost features, acrylic resin is the main material in denture fabrication last 40 years. The purpose of this study is to improve mechanical properties of acrylic based dental composites used in dentistry by applying nanofiber approaches. Polymethylmethacrylate (PMMA) is commonly used as a base acrylic denture material with benefits of rapid and easy handling but sometime this material can be fractured or cracked in clinical use because of the strength issues that is frequently used in restorative dentistry in recent years. A wide variety of fillers that are used to produce PMMA composites draw the attention in literature. Using PMMA composite resins with electrospun polyvinylalcohol (PVA) nanofiber fillers is our first novelty. Also the producing and using aligned electrospun fibers as a filler is our second novelty of this practice. PVA was selected as composite filler because of biocompatibility and preparing easily also has non-toxic solvent. Electrospinning system is manufactured that allows manipulation of electric field used in the application of alignment in lab scale. Various auxillary electrode systems are used for different patterns of alignment with the manufactured device and electrode systems produce fibers in different range of diameter. Scanning electron microscopy (SEM) is used for physical characterization and determined the range of fiber diameters. After the optimization of concentration step non-woven and aligned fibers are also analyzed. Non-woven fiber has no unique pattern because of the nature of electrospinning but aligned fibers has crossed lines. These produced fibers structured as layer-by-layer form with different features are used in producing PMMA dental composites with different volume ratios. In the last part of the research, PMMA dental composites are produced with aligned and formless fibers that are characterized with three-point bending test. The maximum flexural strength figure shows that fiber load by weight %0.25 and above improves the maximum. The change of flexural strength, elastic modulus values and toughness are obtained and compared with formless and aligned PVA nanofiber included composite specimens. As a result, mechanical properties of PMMA dental composites are improved with using PVA nanofibers as a filler also with the usage of aligned fibers instead of the formless ones the effects of improvement gets better with maximum values as 5.1 MPa (flexural strength), 0.8 GPa (elastic modulus), 170kJ/m3 (toughness).

Effect of Acid Hydrolysis Conditions on the Properties of Cellulose Nanoparticle-Reinforced Polymethylmethacrylate Composites.

Cellulose nanoparticles (CNPs) were prepared from microcrystalline cellulose using two concentration levels of sulfuric acid (i.e., 48 wt% and 64 wt% with produced CNPs designated as CNPs-48 and CNPs-64, respectively) followed by high-pressure homogenization. CNP-reinforced polymethylmethacrylate (PMMA) composite films at various CNP loadings were made using solvent exchange and solution casting methods. The ultraviolet-visible (UV-vis) transmittance spectra between 400 and 800 nm showed that CNPs-64/PMMA composites had a significantly higher optical transmittance than that of CNPs-48/PMMA. Their transmittance decreased with increased CNP loadings. The addition of CNPs to the PMMA matrix reduced composite’s coefficient of thermal expansion (CTE), and CNPs-64/PMMA had a lower CTE than CNPs-48/PMMA at the same CNP level. Reinforcement effect was achieved with the addition of CNPs to the PMMA matrix, especially at higher temperature levels. CNPs-64/PMMA exhibited a higher storage modulus compared with CNPs-48/PMMA material. All CNP-reinforced composites showed higher Young’s modulus and tensile strengths than pure PMMA. The effect increased with increased CNP loadings in the PMMA matrix for both CNPs-64/PMMA and CNPs-48/PMMA composites. CNPs affected the Young’s modulus more than they affected the tensile strength.

Indentation and scratch behavior of functionalized MWCNT–PMMA composites at the micro/nanoscale

Polymethylmethacrylate (PMMA) and functionalized multiwalled carbon nanotube (F‐MWCNT) based composite films were prepared using solution casting method. Nanoindentation and scratch measurements were carried out to study the influence of F‐MWCNT as the reinforcement on the mechanical properties of the composite at the sub‐micron scale. The composites were prepared with varying weight percentages of F‐MWCNT in the PMMA matrix. The composites containing an adequate amount (0.25 wt%) of F‐MWCNT was found to demonstrate the maximum nanomechanical properties, viz. hardness, elastic modulus, recovery index. Scratch resistance measured in terms of coefficient of friction, also showed maximum value for the PMMA composite reinforced with 0.25 wt% of F‐MWCNT. POLYM. COMPOS., 35:948–955, 2014. © 2013 Society of Plastics Engineers

Optical limiting effect and ultrafast saturable absorption in a solid PMMA composite containing porphyrin-covalently functionalized multi-walled carbon nanotubes

A versatile solid Poly-methyl-methacrylate (PMMA) composite containing porphyrin-covalently functionalized multi-walled carbon nanotubes (MWNTs-TPP) was prepared through free radical polymerization without additional dispersion stabilizer. Using nanosecond, femtosecond pulse Z-scan and degenerate femtosecond pump-probe techniques, we studied the optical limiting effect, ultrafast saturable absorption and transient differential transmission of the composite. Results show that the solid composite exhibits weaker optical limiting effects than that of the suspension at 532 nm under nanosecond pulse, due to the absence of nonlinear scattering mechanism. The composite also shows ultrafast saturable absorption with a relaxation time about 190 fs at 800 nm under femtosecond pulse due to band-filling effect, comparably to the suspension. The versatile solid composite can be the candidate for uses in applications of ultrafast optical switching and mode-locking element or optical limiter for nanosecond pulse.

Metal-organic framework polymethyl methacrylate composites for open-tubular capillary electrochromatography

Metal-organic frameworks (MOFs) are attractive as novel separation medium due to their distinguished properties including large surface area, accessible tunnels and diverse structures. Here, we report the incorporation of MOF CAU-1 (CAU=Christian-Albrechts-University) into polymethyl methacrylate (PMMA) to produce a new composite (CAU-1@PMMA), and the fabrication of CAU-1@PMMA coated capillary for open tubular capillary electrochromatography (CEC). CAU-1 contains unprecedented [Al8(OH)4(OCH3)8]12+ clusters connected by twelve aminoterephthalic acid linkers, and is highly porous and stable in a variety of buffer solutions. The incorporation of CAU-1 into PMMA not only increases surface area, but also electroosmotic flow (EOF). As a result, the CAU-1@PMMA coated capillary column gives higher column efficiency, larger column capacity, and shorter separation time for baseline separation of two groups of aromatic carboxylic acids than the PMMA coated capillary column. Besides, the incorporation of CAU-1 also improves the resolution for the CEC separation of basic sulfa drugs and structurally related peptides. The run-to-run, day-to-day and column-to-column precision for the EOF of CAU-1@PMMA coated capillary column is 0.3%, 0.4%, and 2.2% (relative standard deviation), respectively. The results show that MOFs composites are promising stationary phases for CEC applications.

Preparation of functionalized graphene by simultaneous reduction and surface modification and its polymethyl methacrylate composites through latex technology and melt blending

Graphene is a kind of very promising filler for polymer composites, but its irreversible aggregation when introduced into polymers is a challenge for property enhancements and limits its industrial application. To address this, we report one-step covalent functionalization and simultaneous reduction of graphite oxide (GO) with hydroxyethyl acrylate (HEA), resulting in a functionalized graphene with double bonds. The functionalized graphene obtained, noted as FGN, is successfully incorporated into polymethyl methacrylate (PMMA) matrix by latex technology and melt blending. Latex technology is used for the pretreatment of FGN through emulsion copolymerization between methyl methacrylate (MMA) monomers and FGN double bonds. After pretreatment of FGN, covalent attachment of PMMA particles to the edges of FGN sheets can effectively prevent their agglomeration and markedly improve their dispersion in the polymer matrix. Since these PMMA particles act as good compatibilizers in the interface between FGN and PMMA matrix during the melt mixing process, the PMMA/FGN composites obtained exhibit exfoliated morphology and very good dispersion, as evinced by the results from X-ray diffraction (XRD) and transmission electron microscopy (TEM). When even a small amount of FGN (⩽1.0wt%) is incorporated, the thermal properties and mechanical properties of PMMA/FGN composites are enhanced significantly. The glass transition temperature (Tg) increases from 103.8 to 110.5°C, while the tensile strength increases by 31.0% (1.0wt% FGN addition). Moreover, the storage modulus of PMMA/FGN composites increases by 27% (1.0wt% FGN addition) at room temperature. These enhancements are attributed to the strong chemical interaction between the FGN sheets and PMMA and the good distribution of FGN sheets in the PMMA matrix.

Ultra-flexible polymethyl methacrylate composites induced by sliding of micron-sized hexagonal boron nitride platelets

Abstract An ultra-flexible hexagonal boron nitride (h-BN)/ polymethyl methacrylate (PMMA) composite with extra-large elongation at rupture was prepared by introducing micron-sized surface-modified h-BN platelets into a PMMA matrix. At 32 wt% loading of surface-modified h-BN, the composite can be folded freely and has an elongation at rupture of 68%, which is over 30 times larger than that of PMMA. Such results are due to the lubricant nature and the sliding of h-BN platelets.

Evidences for π-interactions between pyridine modified copolymer and carbon nanotubes and its role as a compatibilizer in poly(methyl methacrylate) composites

Abstract Poly(methyl methacrylate-co-methacrylic acid) was modified with 4-aminomethyl pyridine, in order to facilitate π–π interactions with carbon nanotubes. The π–π * transitions of both the carbon nanotubes and the pyridine modified copolymer were observed by X-ray photoelectron and UV–vis spectroscopy, respectively. The π-interactions themselves were evident by UV–vis absorbance quenching and red shift and also by fluorescence emission quenching and blue-shift. Those spectroscopic evidences suggested that the nanotubes were wrapped by the modified copolymer through π–π interactions. Introducing the pyridine modified copolymer as a compatibilizer in polymethyl methacrylate composites enabled improved nanotube dispersion, which led to reductions in volume resistivity and increases in composite storage modulus. Those results indicated that this novel compatibilizer could be suitable for a variety of carbon nanotube/poly(methyl methacrylate) composite based applications, where improved nanotube dispersion is desirable without damaging the nanotubes inherent properties.

A study on nanoindentation and tribological behaviour of multifunctional ZnO/PMMA nanocomposite

This work aims to compare the scratch hardness with the indentation hardness of ZnO nanoparticle reinforced polymethylmethacrylate (ZnO/PMMA) composites obtained from nanoindentation measurements. 50μm thick films ZnO/PMMA nanocomposites were produced by the in-situ spin coating method. Scratch hardness was measured from the scratch width origin at low load during the course of the scratch measurements. A good correlation was found between the scratch hardness and the indentation hardness at low indentation depth, where a linear relationship between hardness and the reinforcement content of ZnO nanoparticles was observed. The composite was structurally established by transmission electron microscopy and furrier transform infrared spectroscopy.

Study on friction and wear behavior of PMMA composites reinforced by HCl-immersed TiO2 particles

Mechanical and tribological properties of polymethyl methacrylate (PMMA) composites filled with titanium oxide (TiO2) were studied with particular interest on the HCl surface treatment. Increasing the TiO2 content in the PMMA matrix from 1 wt% to 7 wt% resulted in improved tensile strength and then decreased. The tensile and tribological properties show the optimum TiO2 content is obtained at 3 wt%. HCl treatment largely improved the friction and wear of TiO2/PMMA composites. Scanning electron microscope (SEM) investigation of worn surfaces of PMMA composites showed that HCl-treated TiO2/PMMA composite had strong interfacial adhesion and smooth worn surface under given load.

The effect of surface chemistry of graphene on rheological and electrical properties of polymethylmethacrylate composites

Graphene sheets with different oxygen contents were prepared to functionalize the electrically insulating polymethylmethacrylate (PMMA). The influences of surface chemistry of graphene on rheological, electrical and electromagnetic interference (EMI) shielding properties of its PMMA composites were investigated. The appearance of frequency-independent storage modulus at low frequency suggests a solid-like viscoelastic behavior and the formation of an interconnected network of graphene in the matrix. Due to the favorable interfacial interactions arising from polarity matching, the graphene with a C/O ratio of 13.2 (graphene-13.2) shows a better dispersion in PMMA than those with lower C/O ratios, and thus its PMMA composites exhibit lower rheological and electrical percolation thresholds. The EMI shielding properties of the graphene/PMMA composites exhibit similar dependence on the oxygen content of graphene. A high EMI shielding effectiveness of ∼30dB was obtained for the PMMA composite with 4.2vol.% of graphene-13.2 with microwave absorption as the dominant EMI shielding mechanism.

Dielectric, mechanical and thermal properties of polymer/BaTiO3 composites for embedded capacitor

Barium titanate (BaTiO3) filled polymethylmethacrylate (PMMA) composites were prepared using the simple solution method followed by hot pressing. The content of BaTiO3 was varied from 0 to 65vol.%. Scanning electron microscopy showed good dispersion and adhesion of BaTiO3 with the PMMA matrix. The dielectric constant of the composites increased significantly. There was weak dispersion in the dielectric constant of the composites (up to 45vol.%) with frequency between 100Hz and 15MHz. The dissipation factor of the composites increased from 0.021 for pure PMMA to 0.029 for 45vol.% composites. However, 65vol.% composite showed dispersion in dielectric constant with increasing frequency and higher dissipation factor. The Lichtenecker equation agreed well with the experimental data. The microhardness and the glass transition temperature of the composites increased approximately 4.7-fold and 42°C, respectively, compared to pure PMMA. The CTE of the 65vol.% composite is close to that of copper.

Thermal conductivity of tunable lamellar aluminum oxide/polymethyl methacrylate hybrid composites

Abstract

Microtomographic evaluation of the bone–cell interactions with a silorane‐based composite

The low-shrink Silorane-based composite could bond effectively to bone and showed the potential be used as a bone cement. Bone organ culture maintains the anatomical order, natural cell-to-cell and cell-to-matrix relationship. The purpose of this study was to evaluate the responses of bone cells to a Silorane-based composite which was compared with a representative polymethyl methacrylate (PMMA) bone cement. The critical size defects were created through the parietal bones from one litter of mice. The paired bones were divided into two groups: Silorane-based composite group and PMMA group. The prepared two groups of disks were put into the defects. The cultures were grown in vitro for 38 days and analyzed with microcomputed-tomography, dissecting-microscope, phase- contrast-microscope, scanning-electron-microscopy, and energy- dispersive-X-ray. At the 10th day, the Silorane disk was almost fully covered by a sheet of cells but the cells hardly attached to the disk surface. The edge of the PMMA disk was covered by a sheet of cells and the migrated individual cells attached to the whole surface of the disk. At the 38th day, some cells attached to the exposed disk area of the Silorane disk while the formed tissues covered the whole surface of the PMMA disk. The collagen fibers, globular deposits and bone formation were visible in both groups. The Silorane-based composite showed promise as a potential bone cement when compared with PMMA which is used in clinical orthopedics. However, the cell attachment to PMMA was evidently better than to Silorane-based composite.

Fabrication and characterization of aluminum nitride polymer matrix composites with high thermal conductivity and low dielectric constant for electronic packaging

Abstract Polymethyl methacrylate (PMMA) composites filled with Aluminum Nitride (AlN) were prepared by powder processing technique. The microstructures of the composites were investigated by scanning electron microscopy techniques. The effect of AlN filler content (0.1–0.7 volume fraction (vf)) on the thermal conductivity, relative permittivity, and dielectric loss were investigated. As the vf of AlN filler increased, the thermal conductivity of the specimens increased. The thermal conductivity and relative permittivity of AlN/PMMA composites with 0.7 vf AlN filler were improved to 1.87 W/(m K) and 4.4 (at 1 MHz), respectively. The experimental thermal conductivity and relative permittivity were compared with that from simulation model.

The mechanical and tribological properties of MAH-grafted HDPE filled SiO2/PMMA composite

Maleic anhydride–grafted high-density polyethylene (HDPE; PE- g-MAH) was used to fill the interphase layer of silicon dioxide (SiO2)/polymethyl methacrylate (PMMA) composites. The mechanical, friction and wear properties of SiO2/PMMA/HDPE composites were investigated on a ring-on-ring friction and wear tester with AISI 1045 steel metallic ring counterface under dry friction conditions. Scanning electron microscopy (SEM) was utilized to study the worn surfaces of PMMA composites. Experimental results showed that the addition of HDPE decreased the friction coefficient of SiO2/PMMA composites slightly and reduced the wear volume loss of the PMMA composites obviously. SEM studies indicated that the addition of HDPE could reduce the abrasive wear of SiO2/PMMA composites. The dispersion of SiO2 in PMMA composites was also improved.

Effect of MCM-41 and SBA-15 Mesoporous Molecular Sieves on Properties of PMMA-Based Composite

Effects of different pore size nano-mesoporous molecular sieves fillers, i. e. MCM-41, SBA-15, together with organic-montmorillonite (OMMT), mixture of OMMT/MCM-41 or OMMT/SBA-15 (m (OMMT): m (MCM-41)/m (SBA-15) =1:1) and their amounts on mechanical properties of the polymethylmethacrylate (PMMA) composites were investigated. When the amount of OMMT/SBA-15 mixture was 0.5 %, tensile strength of the nano-composite reached maximum values of 46.3 MPa. When OMMT/SBA-15 mixture addition amount w (filler) was 1.2 %, impact strength of the nano-composite reached maximum values of 14 KJ/m2. In comparison with PMMA without any filler, the tensile strength and impact strength of nano-composite were increased by 8.4 % and 48 %, respectively.

Preparation and Characterization of Polypyrrole-Modified Henequen Fiber-Reinforced Polymethylmethacrylate Composites

Polypyrrole modified henequen conductive fibers were prepared by insitu chemical polymerization of pyrrole in presence of henequen fiber using FeCl3 as oxidant. The fibers were initially treated with alkali solution, then modified with polypyrrole and were investigated for their electrical properties, mechanical properties, ATR, SEM and XRD. The resulting material had electrical performance and mechanical properties depending on the thickness of the polypyrrole coating and treatment conditions. Polymethylmethacrylate composites having uniform dispersion of surface treated polypyrrole coated henequen fiber were prepared and characterized. Mechanical properties, thermal properties and electrical properties of polymer composites are reported.

Electrostatically Functionalized Multiwalled Carbon Nanotube/PMMA Composite Thin Films for Organic Vapor Detection

Thin-film composites of polymethylmethacrylate (PMMA) with multiwalled carbon nanotubes (MWCNTs) and corona based electrostatically functionalized multiwalled carbon nanotubes (f-MWCNTs) were drop cast for organic vapor detection. The electrical responses of the composite films were investigated for different organic vapors such as dichloroethane, toluene, chloroform, methanol and benzene at concentrations as low as 100 ppm (parts per million) with average percentage sensitivity as high as 49% for f-MWCNT/PMMA composites. The selectivity of the composite films for different organic vapors was defined based on the response time and percentage sensitivity. Detection with these composite films did not require high temperatures. It is proposed that the sensing mechanism of composite films is based on matrix swelling of the polymer and polar interaction of various vapors with f-MWCNTs.