Pure Poly Methyl Methacrylate Research Articles

Surface Functionalization of Graphene Oxide with Polymer Brushes for Improving Thermal Properties of the Polymer Matrix

In this work, polymethyl methacrylate (PMMA) and polystyrene (PS) with controlled structures would be grafted on graphene material. The hybrid materials were prepared by coating graphene oxide (GO) with polydopamine (PDA) as a reactive underlayer and reducing agent, subsequently, surface-initiated polymerization of monomers (methyl methacrylate, styrene) based on the activators regenerated electron transfer atom transfer radical polymerization (ARGET-ATRP) technique. The polymer brush-modified graphene materials were then incorporated into the PMMA or PS matrix to get polymer nanocomposites with better thermal properties. The results of Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA) demonstrated that PMMA and PS chains were successfully anchored on the surfaces of functionalized GO sheets. The influence of the grafted polymer brush-modified GO on thermal stability of PMMA and PS was investigated by a simultaneous thermal analyzer. Thermal conductivity of the polymer nanocomposite was determined by a conductive calorimeter. The results showed that thermal stability, glass transition temperature ( T g ), and thermal conductivity of the polymer nanocomposites were obviously improved compared with pure PMMA or PS.

A molecular dynamics study on the effect of TSW defective graphene on the glass transition temperature of polymer materials

Molecular models of pristine graphene (GN) and GN with Thrower–Stone–Wales (TSW) defect-reinforced polymethyl methacrylate (PMMA) composites were established. The pure PMMA matrix was developed as a benchmark to study the effect of TSW defective GN (TSW-GN) on the glass transition temperature (Tg) of PMMA composites based on molecular dynamics simulations. The Tg values of these composites were obtained by fitting the scatter plots of the temperature versus the specific volume of the models. The results showed that the introduction of TSW defects can effectively increase the Tg of the PMMA composites. Additionally, the Tg of the PMMA composites gradually increased with an increase in TSW defects on the GN surface. The interaction energy between the TSW-GN and PMMA matrix, the density distribution of PMMA, the mean square displacements of the PMMA chains, and the free volume of these models were analyzed to understand the internal mechanisms with respect to the variations in the Tg from an atomic perspective. It can be concluded that the appropriate introduction of TSW-GN can improve the upper limit of the applied temperature of PMMA composites. In addition, guidance for the use of TSW-GN in different application environments of polymer composites was proposed.

Balanced strength-toughness, thermal conductivity and self-cleaning properties of PMMA composites enabled by terpolymer grafted carbon nanotube

Achieving a balanced strength-toughness in polymer composites is a challenge largely because of poor interfacial interaction between the fillers and matrix. Here, we report that terpolymer grafted multi-wall carbon nanotubes (Ter-CNT) imparted good dispersion of CNT in matrix and strong CNT-matrix interaction. With the addition of 2 vol% filler into polymethyl methacrylate (PMMA) matrix, the composite exhibited simultaneously a balanced strength-toughness property with flexural strength of 72.3 MPa, toughness of 10.1 MJ m−3, which increased by 40.1% and 578% compared with those of pure PMMA. In addition, the composite also shows a high static contact angle (110.3°), and thermal conductivity (0.50 Wm K−1), which endow the composite with good self-cleaning and thermal management capabilities. Thus, this preparation process shows guidance for the design of polymer composite with integrated high strength-toughness, thermal conductivity and good self-cleaning.

Improving flexural properties of polymethyl methacrylate denture filled by carbon nanofibers under low filling content

In this article, we chose carbon nanofibers (CNFs) with high aspect ratio and excellent mechanical strength to investigate the evolution of the assemble behavior belong to the nanofillers and its effect on mechnaical properties of CNFs enhanced polymethyl methacrylate (PMMA) base denture resins. Test specimens were manufactured by mixing 0.5%, 1% and 3% content of CNFs with PMMA powder and the flexural properties of the specimens were tested by three-points testing. Comparing with the low flexural strength of pure PMMA base denture resins, Statistical evaluation results revealed that CNFs fillers highly improved the flexural strength of the composite resins to 66.44 ± 1.40 MPa, 68.75 ± 6.82 MPa and 89.26 ± 1.97 MPa at content reached 0.5%, 1% and 3%, respectively. Flexural modulus of neat PMMA was 2.79 ± 0.48 GPa, and the flexural modulus of the sample contains 0.5%, 1% and 3% reached 6.42 ± 0.75 GPa, 5.95 ± 0.29 GPa and 6.27 ± 0.14 GPa, respectively. Scanning electron microscopy revealed the aggregation of CNFs fillers, which is considered a stereoscopic framework that played the role of a special enhancing reinforcement under low filler content, and this strategy is considered to be expanded and developed to a common strategy that guiding our design in composite denture resins.

Optical studies of Rhodamine B doped polymethyl methacrylate (PMMA) films

In this paper the influence of fluorescent dye doping on the optical properties of polymethylmethacrylate (PMMA), in particular on the optical band gap and refractive index of PMMA host matrix is reported. Solution casting method was used to prepare the films of pure PMMA and rhodamine-B doped PMMA films containing varying levels of doping and their optical properties were evaluated. UV–Visible spectra were used to evaluate the optical parameters; uv-absorption spectra reveal absorption bands between 262 and 284 nm for pure PMMA. However, dye doped PMMA film showed absorption bands in the range between 262 and 560 nm depending upon the degree of doping of dye into the film. Optical absorption measurements showed strong modifications in optical properties as a result of doping dye guest molecules into the host PMMA matrix system. It is observed that all optical parameters such as absorption band, absorption edge, energy band gap (direct and indirect) got affected by doping of the dye. Indirect optical band gap of pure PMMA was observed as 4.72 eV but it reduced to 4.13 eV on incorporation of rhodamine-B into PMMA matrix. Studies on the metallization criterion (M) implicate better scope of electronic mobility with the increase in the dopant concentration into the film.

Mechanical Properties and Electrical Conductivity of Poly(methyl methacrylate)/Multi-walled Carbon Nanotubes Composites

Carbon nanotubes (CNTs) remain one of the most efficient reinforcing material for enhanced mechanical and electrical properties. In this study, the effects of multi-walled CNTs (MWCNTs) fillers on mechanical, structural, and electrical properties of polymethyl methacrylate (PMMA)/MWCNTs composites were studied. The PMMA/MWCNTs composites, containing varying MWCNTs concentration of 0.1, 0.3, and 0.5 wt%, were prepared by a solution casting method. The mechanical properties of the composites such as tensile strength, elongation, Young modulus, tear resistance, fracture energy, impact strength, and hardness were investigated. Results showed that the mechanical properties of the composites were enhanced significantly. At 0.5 wt% MWCNTs, the tensile strength, elongation, tear strength, hardness, fracture energy and impact strength increased by 397%, 567%, 89%, 27%, 12%, and 36%, respectively, while the Young modulus decreased by 26% compared to pure PMMA polymer sample. Both the dc electrical conductivity and the activation energy increased with increased concentration of MWCNTs. From the electrical conductivity measurements, the percolation threshold was found to equal ~ 0.55 wt% MWCNTs. Based on the Fourier-transform infrared spectroscopy analysis, enhancement of mechanical and electrical properties is attributed to the formation of covalent bonds between polymer strands and MWCNTs. Moreover, a mechanism was proposed to describe the influence of MWCNTs on electrical and mechanical properties of PMMA/MWCNTs composites.

The effect of triphenyl phosphate inhibition on flame propagation over cast PMMA slabs

The effect of triphenyl phosphate (TPP) retardant inhibition on flame propagation over the horizontal surface of polymethyl methacrylate (PMMA) has been studied experimentally and numerically. Regarding the flame spread behavior over the surface of PMMA (pure and inhibited by TPP), the following parameters were measured: thermal decomposition with TG / DTG analyzer, the flame spread rate, the pyrolysis zone length, the mass loss rate and spatial distribution of temperature by thermocouples and species concentration in the gas-phase flame by probing mass spectrometry. The previously developed coupled heat and mass transfer mathematical model describing the feedback interaction between flame and solid fuel, as well as volatilization of pyrolysis products, was modified to resolve the effect of TPP on flame spread by introducing the correcting factor of the gas-phase combustion reaction rate relating to the inhibitor concentration in the solid material. Good agreement between the measured and calculated flame spread parameters (flame spread velocity, mass burn-out rate, pyrolysis zone length), as well as a detailed flame structure (gas phase temperature and species concentration), has been obtained for pure PMMA and PMMA+10%TPP. It has been shown that the proposed approach describes a satisfactory retardant effect of TPP on the flame spread over PMMA surface by inhibiting the gas-phase combustion reaction.

Insight into the optical properties of poly-methyl-methacrylate (PMMA) loaded with ferric chloride (FeCl3) in varying concentration

The present work has been carried out to understand the variations in a physical property that occur on insertion of a filler material in a polymer. Here, the authors report the synthesis and optical characterization of thin films of FeCl3 doped poly (methyl methacrylate) (PMMA). These films have been prepared by dispersing FeCl3 in different concentration (1%,2%,4%,8%) in PMMA using the solution casting technique. The thickness of the developed films is 100 μm. The optical properties of pure PMMA film and PMMA films doped with FeCl3 were investigated by recording the transmittance data on EI 2375 UV–VIS double beam spectrophotometer in the wavelength range 400–1100 nm. Results show that transmittance of the films decreases as the concentration of metal salt increases, attaining a minimum transmittance of 59% for 8 wt% of filler. This transmission data is further used to evaluate all other optical parameters like absorption coefficient (α), extinction coefficient (κ), refractive index (η), real and imaginary parts of dielectric constant (εr andεi), optical conductivity (σ) and skin depth (χ). The optical energy band gaps (Eg) have also been calculated.

Impact Strength, Flexural Modulus and Wear Rate of PMMA Composites Reinforced by Eggshell Powders

In the present study, the impact strength, flexural modulus, and wear rate of poly methyl methacrylate (PMMA) with eggshell powder (ESP) composites have been investigated. The PMMA used as a matrix material reinforced with ESP at two different states (including untreated eggshell powder (UTESP) and treated eggshell powder (TESP)). Both UTESP and TESP were mixed with PMMA at different weight fractions ranged from (1-5) wt.%. The results revealed that the mechanical properties of the PMMA/ESP composites were enhanced steadily with increasing eggshell contents. The samples with 5 wt.% of UTESP and TESP additions give the maximum values of impact strength, about twice the value of the pure PMMA sample. The calcination process of eggshells powders gives better properties of the PMMA samples compared with the UTESP at the same weight fraction due to improvements in the interface bond between the matrix and particles. The wear characteristics of the PMMA composites decrease by about 57% with increases the weight fraction of TESP up to 5 wt.%. The flexural modulus values are slightly enhanced by increasing of the ESP contents in the PMMA composites.

Preparation and Characterization of Poly Methyl Methacrylate/Clay Nanocomposite Powders by Microwave-Assisted In-Situ Suspension Polymerization.

The PMMA (poly methyl methacrylate)/clay nanocomposite powders were synthesized by In-Situ suspension polymerizations using microwave heating. The PMMA/clay nanocomposites were also sampled using injection moulding to make specimens for material characterization. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) indicated the formation of a highly intercalated clay layer in the nanocomposites. It was found that the microstructure of PMMA/clay nanocomposites was strongly dependent of content of clay. Thermo gravimetric analysis (TGA) indicated an improvement in the thermal stability of nanocomposites compared to that of the pure PMMA. Differential scanning calorimetry (DSC) showed that the nanocomposites had a higher glass transition (Tg) temperature than the PMMA. Fourier-transform infrared (FT-IR) spectroscopy indicated an interaction between the carbonyl group of PMMA and hydroxyl group of the clay. Therefore, a possible reason in enhanced material properties of nanocomposites is that the chemical interaction and nanostructure of PMMA polymer and intercalated inorganic silicate layer has increased the thermal stability of the PMMA/clay nanocomposites.

Evaluation of Equivalent Flexural Strength for Complete Removable Dentures Made of Zirconia-Impregnated PMMA Nanocomposites.

High-impact (HI) polymethyl methacrylate (PMMA), obtained from modification of conventional PMMA, is commonly used in prosthodontics as a denture base material for improved impact resistance. However, it suffers from poor flexural strength properties. The aim of this study was to investigate the flexural strength of complete removable dentures made of HI heat-polymerised PMMA resin reinforced with zirconia nanoparticles at two different concentrations. The effect of fatigue loading on the flexural strength behaviour of the dentures was also investigated. A total of 30 denture specimens were fabricated from PMMA with different concentrations of zirconia nanoparticles: 0 (control), 3, and 5 wt.%. Ten specimens in each group were divided into two subgroups, with five specimens in each, to conduct both flexural strength and fatigue loading test of each of the subgroups. Fatigue loading was applied on the dentures using a mastication simulator and equivalent flexural strength was calculated with data from bending tests with and without fatigue cyclic loading. One-way analysis of variance (ANOVA) of the test data was conducted with the Bonferroni significant difference post-hoc test at a preset alpha value of 0.05. Paired t-test was employed to identify any difference between the specimens with and without the application of fatigue loading. The fractured surface of the denture specimens was examined with a scanning electron microscope (SEM). The bending tests demonstrated that the mean equivalent flexural strength of reinforced HI PMMA denture specimens with 5 wt.% zirconia nanoparticles increased significantly (134.9 ± 13.9 MPa) compared to the control group (0 wt.%) (106.3 ± 21.3 MPa) without any fatigue loading. The mean strength of the dentures with PMMA +3 wt.% zirconia also increased, but not significantly. Although the mean strength of all specimen groups subjected to fatigue loading slightly decreased compared to that of the specimen groups without any fatigue cyclic loading, this was not statistically significant. Denture specimens made of HI heat-polymerised PMMA reinforced with 5 wt.% zirconia nanoparticles had significantly improved equivalent flexural strength compared to that made of pure PMMA when the specimens were not subjected to any prior fatigue cyclic loading. In addition, the application of fatigue cyclic loading did not significantly improve the equivalent flexural strengths of all denture specimen groups. Within the limitations of this study, it can be concluded that the use of zirconia-impregnated PMMA in the manufacture of dentures does not result in any significant improvement for clinical application.

Synthesis and Study on Thermal Stability of PMMA Microspheres by Emulsion Polymerization

Polymethyl methacrylate (PMMA) was prepared by emulsion polymerization using methyl methacrylate (MMA) as monomer, potassium per sulfate as initiator. Polymethyl methacrylate/mesoporous molecular sieve composite (PMMA/MCM-48) was synthesized via the addition of mesoporous molecular sieve MCM-48 silica nanomaterial. The synthesized samples were systematically characterized using XRD, SEM, TEM, FT-IR, and TG. The results showed that PMMA microspheres with a diameter of 80-110 nm were prepared by emulsion polymerization. Compared with pure PMMA, PMMA/mesopores molecular sieve MCM-48 composites have good thermal stability. Pure PMMA microspheres can be completely decomposed at a lower temperature (400°C), and the thermal stability of PMMA/MCM-48 composites were improved by the addition of mesoporous molecular sieves.

Synergetic enhancement of thermal conductivity in the silica-coated boron nitride (SiO2@BN)/polymethyl methacrylate (PMMA) composites

High thermal conductivity polymer composites have increased application in modern electronics. To achieve high thermal conductivity at relatively low filler content, two critical approach are used: surface modification of the filler and construction of thermal conductive network in polymer composites. This article provided a new simple and feasible method to modify h-BN consisting of physical absorption of polyvinylpyrrolidone (PVP) and hydrolysis of tetraethyl orthosilicate (TEOS). Then, SiO2@BN/PMMA composites were fabricated via solution-mixing and hot compression. The surface modification of BN enhanced the interface interaction between adjacent BN, which led to reduced thermal resistance and phonon scattering. The solution-mixing and hot compression process ensured the formation of thermal conductive pathway at the same time. The highest thermal conductivity of 40 vol% SiO2@BN/PMMA composite reached 5.583W /m K, which exhibited 3292% and 200% enhancement compared with the pure PMMA and melt-mixing BN/PMMA composites, respectively.

Electrophoretic deposition of polymethylmethacrylate and composites for biomedical applications

For the first time, an electrophoretic deposition (EPD) method has been developed for the deposition of polymethylmethacrylate (PMMA) and PMMA-alumina films for biomedical implant applications. The proposed biomimetic approach was based on the use of a bile salt, sodium cholate (NaCh), which served as a multifunctional solubilizing, charging, dispersing and film-forming agent. Investigations revealed PMMA-Ch− and PMMA-alumina interactions, which facilitated the deposition of PMMA and PMMA-alumina films. This approach allows for the use of a non-toxic water-ethanol solvent for PMMA. The proposed deposition strategy can also be used for co-deposition of PMMA with other functional materials. The PMMA and composite films were tested for biomedical implant applications. The PMMA-alumina films showed statistically improved metabolic results compared to both the bare stainless steel substrate and pure PMMA films. Alkaline phosphatase (ALP) activity affirmed the bioactivity and osteoconductive potential of PMMA and composite films. PMMA-alumina films showed greater ALP activity than both the PMMA-coated and uncoated stainless steel.

Effect of carbon nano-dots (CNDs) on structural and optical properties of PMMA polymer composite

In this report direct band gap polymer composites with amorphous structure were fabricated which are important for applications in optoelectronic devices. Solution cast technique has been used for the preparation of polymethyl methacrylate (PMMA)/carbon nanodots (CNDs) nanocomposite films. The Fourier-transform infrared spectroscopy (FTIR) outcomes display the occurrence of complexation between PMMA and CNDs. The analysis of X-ray diffraction (XRD) shows an improvement of amorphous phase of PMMA with CNDs addition. The surface morphology of the films was examined by means field emission scanning electron microscopy (FESEM) technique. CNDs are formed and distributed in the FESEM composite image. Photoluminescence (PL) spectroscopy study showed that the PMMA/CNDs nanocomposite film emission is dominated by a broad-band around 480 nm, exhibiting a well-defined excitonic emission feature. From Ultraviolet–visible (UV–Vis) spectroscopy study, the optical band gaps of pure PMMA and PMMA/CNDs nanocomposite films were calculated. The dispersion behaviour of the refractive index of PMMA was shifted to higher wavelength upon doping with CNDs. The optical dielectric loss was used to specify the most probable electron transition type. Due to the enhancement of the UV–Vis absorption and photoluminescence behaviour, this nanocomposite film could be considered as a promising candidate to be used in future nanotechnology-based devices.

Effect of cellulose nanofiber content on flexural properties of a model, thermoplastic, injection-molded, polymethyl methacrylate denture base material

Cellulose nanofiber (CNF) made from wood-derived fiber is considered as a potential alternative reinforcing material to conventional fibers. The aim of this study was to investigate the effect of CNF on the flexural properties of CNF-reinforced, injection molded, polymethyl methacrylate (PMMA) denture base material. Test specimens were fabricated from a model thermoplastic denture base resin using the injection molding technique. The resin pellets were mixed with CNF (to obtain different weight percentages 5, 10, 15, and 23 wt%). PMMA without CNF served as the control (0 wt%). Prior to the testing, the test specimens (n = 12/group) were water-immersed at 37 °C water for 50 h. The flexural strengths and moduli of the specimens were determined using three-point bending tests. Statistical evaluation included a one-way analysis of variance and the Student-Newman-Keuls test (α = 0.05). The mean and standard deviation of flexural strengths with the addition of 0, 5, 10, 15 and 23% CNF were 49.4 (±0.7), 56.4 (±1.3), 63.5 (±2.0), 72.0 (±4.7), and 96.8 (±4.0) MPa, respectively. The mean and standard deviation of flexural modulus with the addition of the same concentrations of CNF were 1.31 (±0.02), 1.56 (±0.05), 1.99 (±0.14), 2.40 (±0.15), and 3.96 (±0.08) GPa, respectively. The flexural strengths and moduli of the CNF-reinforced PMMA were significantly higher than those of pure PMMA (p < 0.05). Hence, incorporation of CNF can significantly improve flexural properties of a thermoplastic PMMA denture base material.

A promising material for bone repair: PMMA bone cement modified by dopamine-coated strontium-doped calcium polyphosphate particles.

Polymethyl methacrylate (PMMA) bone cement has been widely used in clinics as bone repair materials for its excellent mechanical properties and good injection properties. However, it also has defects such as poor biological performance, high temperature, and the monomer has certain toxicity. Our study tried to modify the PMMA bone cement by doping with various particle weight fractions (5, 10 and 15%) of SCPP particles and polydopamine-coated SCPP particles (D/SCPP) to overcome its clinical application disadvantages. Our study showed that all results of physical properties of samples are in accordance with ISO 5833. The 15% D/SCPP/PMMA composite bone cement had much better biocompatibility compared with pure PMMA bone cement and SCPP/PMMA composite bone cement due to the best cell growth-promoting mineralization deposition on the surface of 15% D/SCPP/PMMA composite bone cements and Sr2+ released from SCPP particles. Our research also revealed that the reaction temperature was found to be reduced with an increase in doped particles after incorporating the particles into composite bone cements. The novel PMMA bone cements modified by D/SCPP particles are promising materials for bone repair.

Scratch damage behaviors of PVDF/PMMA multilayered materials: Experiments and finite element modeling

In this work, polyvinylidene fluoride (PVDF)/polymethyl methacrylate (PMMA) alternating multilayered materials were fabricated. Firstly, the scratch damage behaviors of PVDF side was investigated experimentally. The results presented that the maximum of critical normal load of scratch damage (Fcr) was obtained by 32-layer material, which was 40% higher than that of pure PVDF and very close to that of pure PMMA. This indicated that the scratch resistance of PVDF could be significantly improved via multilayer assembly with PMMA. Furthermore, numerical modeling revealed that with the multiplication of layers, the decrease of tensile stress imposed on the first PVDF layer led to the delay of scratch damage, whereas the decrease of the distance between the first PMMA layer and the scratch tip promoted its early damage. Therefore, the optimum scratch performance was determined by the critical thickness of PVDF and PMMA layers, which was significant for designing scratch-resistant materials.

Zinc Oxide Nanoparticles Cytotoxicity and Release from Newly Formed PMMA-ZnO Nanocomposites Designed for Denture Bases.

The goal of the study was to investigate the level of zinc oxide nanoparticles (ZnO NPs) release from polymethyl methacrylate (PMMA)–ZnO nanocomposites (2.5%, 5%, and 7.5% w/w), as well as from the ZnO NPs layer produced on pure PMMA, and the impact of the achieved final ZnO NPs concentration on cytotoxicity, before the potential use as an alternative material for denture bases. The concentration of ZnO nanoparticles released to the aqueous solution of Zn2+ ions was assessed using optical emission spectrometry with inductively coupled plasma (ICP-OES). In the control group (pure PMMA), the released mean for ZnO was 0.074 mg/L and for individual nanocomposites at concentrations of 2.5%, 5%, and 7.5% was 2.281 mg/L, 2.143 mg/L, and 3.512 mg/L, respectively. The median for the ZnO NPs layer produced on PMMA was 4.878 mg/L. In addition, in vitro cytotoxicity of ZnO NPs against the human HeLa cell line was determined through the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) dye. The cytotoxicity studies demonstrate that ZnO nanoparticles in the concentrations up to 20 mg/L have no adverse effect on HeLa cells. When compared with the released and cytotoxic concentrations of ZnO NPs, it can be expected that ZnO released from dental prostheses to the oral cavity environment will have no cytotoxic effect on host cells.

Elastic properties of polymer composites reinforced with C60 fullerene and carbon onion: Molecular dynamics simulation

In this paper, the elastic properties of polymer nanocomposites reinforced with C60 fullerene and C60@C240 carbon onion are estimated by using a molecular dynamic (MD) simulation. The nanocomposites are constructed by embedding the buckminsterfullerene and the carbon onion into an amorphous polymer matrix with different weight fractions. The poly methyl methacrylate (PMMA) is chosen as the polymer matrix. The results demonstrate that Young's modulus of the composite increases with increasing the weight fractions of the nanoscopic additives, which is consistent with experimental observations. The nanocomposite containing 4 wt% of C60 exhibits Young's modulus of 3.774 GPa that is 24% higher than pure PMMA. In addition, the validity of the present simulation is verified by the comparison with the experimental results.