Poly Methyl Methacrylate Nanocomposites Research Articles

Optimization of the Mechanical Properties and the Cytocompatibility for the PMMA Nanocomposites Reinforced with the Hydroxyapatite Nanofibers and the Magnesium Phosphate Nanosheets.

Commercial poly methyl methacrylate (PMMA)-based cement is currently used in the field of orthopedics. However, it suffers from lack of bioactivity, mechanical weakness, and monomer toxicity. In this study, a PMMA-based cement nanocomposite reinforced with hydroxyapatite (HA) nanofibers and two-dimensional (2D) magnesium phosphate MgP nanosheets was synthesized and optimized in terms of mechanical property and cytocompatibility. The HA nanofibers and the MgP nanosheets were synthesized using a hydrothermal homogeneous precipitation method and tuning the crystallization of the sodium-magnesium-phosphate ternary system, respectively. Compressive strength and MTT assay tests were conducted to evaluate the mechanical property and the cytocompatibility of the PMMA-HA-MgP nanocomposites prepared at different ratios of HA and MgP. To optimize the developed nanocomposites, the standard response surface methodology (RSM) design known as the central composite design (CCD) was employed. Two regression models generated by CCD were analyzed and compared with the experimental results, and good agreement was observed. Statistical analysis revealed the significance of both factors, namely, the HA nanofibers and the MgP nanosheets, in improving the compressive strength and cell viability of the PMMA-MgP-HA nanocomposite. Finally, it was demonstrated that the HA nanofibers of 7.5% wt and the MgP nanosheets of 6.12% wt result in the PMMA-HA-MgP nanocomposite with the optimum compressive strength and cell viability.

Mechanical and Tribological Performance of Self-Cured Poly Methyl Methacrylate Reinforced by Alumina Nanowires and Zirconia Nanoparticles for Denture Applications

Polymethyl methacrylate (PMMA) is one of the common widely accepted biomaterials in prosthetic dentistry due to its acceptable advantages, since 1937. In the present work, PMMA reinforced with Al2O3 nanowires (Al2O3 NWs) and ZrO2 nanoparticles (ZrO2 NPs) were fabricated by a self-curing method. Mechanical and tribological tests were conducted to study the effect of nanofillers on the mechanical and tribological performance of PMMA nanocomposites. Compression and microhardness tests, as mechanical tests, were accomplished to estimate the elastic modulus and microhardness number of the present nanocomposites. Also, tribological properties of unfilled PMMA and its nanocomposites were realized by pin-on-disk tester under dry sliding conditions. Wear test was conducted at room temperature under applied loads of 10, 20, 30, 40, and 50 N at a constant sliding speed and distance of 1.256 m/s and 226 m, respectively to study wear rate and coefficient of friction (COF) of the nanocomposites. Experimental results revealed that the elastic modulus, microhardness, wear rate, and COF were enhanced with increasing nanofiller content up to 0.5 and 0.7 wt. % of Al2O3 NWs and ZrO2 NPs, respectively. Also, wear rate increased with increasing applied loads up to 50 N, while COF decreased with increasing applied loads up to 40 N. Finally, specimens� worn surfaces were examined and imaged using scanning electron microscope (SEM).

Optical linearity and nonlinearity, structural morphology of TiO2-doped PMMA/FTO polymeric nanocomposite films: Laser power attenuation

This current study suggests a novel optical nanocomposite polymethyl methacrylate (PMMA) with titanium oxide (TiO2) nanoparticles at different concentrations, synthesizing an effective, unexpansive spin coating technique. Adding to that, using both the X-ray diffraction (XRD) method and Fourier transform infrared (FTIR) spectroscopy were very beneficial to study the consistent changes of grain size and strain in nanoscale for the combination of TiO2 nanoparticles in the host PMMA matrix. The topological structure images were observed by atomic force microscopy (AFM), and it was in good agreement with XRD analysis. Both linear and nonlinear optical parameters of the prepared TiO2/PMMA/FTO films were carried out using a VU-Vis-NIR spectrophotometer. Optimized reduction of the optical direct energy bandgap to around ∼ 3.35 eV and indirect bandgap to about 2.37 eV was determined. The obtained results illustrated under study, leading to promising technological applications. Such high structure stability, large dielectric constant, reduced optical bandgap, as well as higher nonlinear optical properties, concluded that the nano-TiO2 powder mix with PMMA can enhance the morphology and optical properties of the host PMMA polymer and that the uniform prepared TiO2 /PMMA nanocomposites are excellent candidates to be used in different applied optoelectronic devices.

Effects of defects on the interfacial shear characteristics between graphene and poly (methyl methacrylate)

AbstractPullout simulations were conducted to investigate the interfacial shear properties between defective graphene (DGr) and polymethyl methacrylate (PMMA) through molecular dynamics simulations with ReaxFF reactive force fields. The effects of number of defects (Stone‐Wales [SW] and double‐vacancy [DV] defects) were investigated. Our results showed that these two types of defects can obviously enhance the interfacial shear strengths of DGr /PMMA nanocomposites. And the DV defects have a greater contribution to the interfacial shear strength enhancement compared to the SW defects. Analysis of the morphology of DGr indicated that surface roughness, which was induced by defects, plays an important role in enhancing the interfacial shear strength at the interface between the DGr and PMMA. Moreover, the effects of chemical functionalization at the defect sites were also investigated. We observed that the CO bonds of functional groups (hydroxyls) at defect sites inclined from the datum plane (z = 0 plane) of the graphene sheet. The inclination of CO bonds, which weakened the mechanical interlocking between functional graphene and PMMA matrix, differently influenced by the DV defect and SW defect.

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.

Effects of nanobarium titanate on physical and mechanical properties of poly(methyl methacrylate) denture base nanocomposites

The aim of this study was to (1) fabricate polymethyl methacrylate (PMMA) nanocomposites having better mechanical strength, (2) investigate the effects of nanobarium titanate (NBT) loadings (1–9 wt%) on tensile and flexural properties, and (3) evaluate surface roughness and hardness of the PMMA nanocomposites. The NBT was treated using a titanate coupling agent. Density, polymerization shrinkage (PS), surface roughness, and hardness were investigated. Tensile and flexural properties of PMMA nanocomposites were also evaluated. The roughness values of PMMA nanocomposites were significantly lower than those values proposed as a reference for clinical use (<200 nm). Moreover, the flexural modulus of the NBT/PMMA nanocomposites increased with increasing filler loadings. A remarkable increase in the tensile modulus values of filled PMMA was also observed ( p < 0.001). In the case of higher filler content, tensile modulus remains unaffected by filler incorporation. The tensile and flexural strength improved with increasing concentration of NBT up to 5 wt% and then decreased by an additional amount of NBT introduced into the nanocomposite resin. However, the tensile and flexural strength values of NBT/PMMA nanocomposites were higher than the PMMA matrix ( p < 0.001). Such enhancements obtained with titanate-treated NBT could lead to the promotion of the dental composites’ longevity.

Correction to: Fabrication, physical and optical properties of functionalized cellulose based polymethylmethacrylate nanocomposites

The original version of the article unfortunately contained an error in Author names and the affililiations.

Exploring the direct effect of intermediate band semiconductor materials on the structural, thermal and optical properties of PMMA nanocomposite

In this work, polymethylmethacrylate (PMMA) doped with SnS2, Sn0.75Fe0.25S2, and Sn0.75Cr0.25S2 nanoparticles films were prepared using both thermolysis and casting procedures. The purity, structural and shape of the nanofillers were confirmed by Rietveld refinement method. The compositional changes for nanocomposite films were studied by energy dispersive spectrometry technique. Nanoparticles morphology and particle size were examined by transmission electron microscopy (TEM) technique. Proper interactions between added nanofillers and the polymer matrix were discussed in detail by Fourier transform infrared spectroscopy technique (FTIR). The variations in the FTIR absorption bands position and their shape proved the effect of doping on the composite films. The effect of dopant elements on the thermal properties of PMMA polymer matrix has been investigated by thermogravimetric analysis (TGA). Results showed an improvement in the degradation temperature of doped polymers compared to undoped ones. Clear regular arrangements of images for nanoparticles and composite films have been represented by scanning electron microscopy (SEM). Different optical parameters have been examined using UV–vis spectroscopy technique. Due to the high transmittance values in the wavelength range of 320–800 nm, the formed composite films could be used as protective window layers for solar cells. The energy gap values decreased from 4.3 eV for undoped PMMA polymer to 4, 3.85, and 3.16 eV depending on the doping element.

Multifunctional Applications of Graphene-Doped PMMA Nanocomposite Membranes for Environmental Photocatalytic

Graphene (GNP)-filled polymethyl methacrylate (PMMA) nanocomposites (NCs) were prepared using a facile casting method. Nanocomposites were fully identified through X-ray diffraction and scanning electron microscopy which confirms some interactions between PMMA and GNP layers lead to a reduction in nanocomposite crystallinity. In this work, the impact of graphene on the optical, electrical characteristics and photocatalytic activity of PMMA polymeric matrix. The rapid increase in absorbance values was observed in the UV-region was linked to the optical transitions of GNP electrons from the valence band to the conduction band. Both the bandgaps (E and E ) have been reduced with graphene addition. The calculated Urbach’s Band tail has been increased with GNP content. With the enhanced frequency and GNP contents, the AC electrical conductivity tends to rise. A 1.665 wt% GNP/PMMA exhibits the most effective activity in amoxicillin photodegradation under visible radiation at 30 min due to decrease electron–hole recombination. The kinetics of the photodegradation process was investigated. The GNP/PMMA nanocomposites are a promising candidate in electronic, optoelectrical and environmental applications.

Fabrication, physical and optical properties of functionalized cellulose based polymethylmethacrylate nanocomposites

An organic–inorganic functionalized nano-filler (CNC–TiO2), was prepared by loading titanium dioxide nanoparticles (TiO2) onto the crystalline nanocellulose (CNC) surface by using methacrylatesilane as cross-link agent in order to enhance compatibility between nanofiller and matrix (PMMA). Nanocomposite films (PMMA/CNC–TiO2) were prepared by free radical copolymerization of various amount (0–5 wt%) of functionalized nanofiller (CNC–TiO2) with methylmethacrylate (MMA) as main monomer, followed by solvent casting technique. The films were characterized using TEM, FTIR, FEG-SEM, and XRD, TGA, and UV–VIS spectroscopy. The results of TEM and FTIR confirmed the modification of CNC with TiO2 and the interaction between the CNC–TiO2 nanofiller and PMMA. FEG-SEM results showed a uniform dispersion of the nanofiller in the PMMA matrix whereas EDX confirmed the presence of TiO2 in the nanocomposite films. The effect of the nanofiller on the mechanical properties of PMMA was also investigated and the results showed significant improvement in tensile and modulus strengths with increasing amounts of nanofiller. In addition, TGA results demonstrated remarkable improvements in the thermal properties of the PMMA/CNC–TiO2 nanocomposite films UV results showed a response to UV absorbance due to incorporation of TiO2. Nanocomposite films can be beneficial for a variety of applications such as coating materials for windows, shelters, glazing, optical filters, and as hard packaging with UV-blocking properties.

Investigating the Mechanical Properties of ZrO2-Impregnated PMMA Nanocomposite for Denture-Based Applications.

Acrylic resin PMMA (poly-methyl methacrylate) is used in the manufacture of denture bases but its mechanical properties can be deficient in this role. This study investigated the mechanical properties (flexural strength, fracture toughness, impact strength, and hardness) and fracture behavior of a commercial, high impact (HI), heat-cured denture base acrylic resin impregnated with different concentrations of yttria-stabilized zirconia (ZrO2) nanoparticles. Six groups were prepared having different wt% concentrations of ZrO2 nanoparticles: 0% (control), 1.5%, 3%, 5%, 7%, and 10%, respectively. Flexural strength and flexural modulus were measured using a three-point bending test and surface hardness was evaluated using the Vickers hardness test. Fracture toughness and impact strength were evaluated using a single edge bending test and Charpy impact instrument. The fractured surfaces of impact test specimens were also observed using a scanning electron microscope (SEM). Statistical analyses were conducted on the data obtained from the experiments. The mean flexural strength of ZrO2/PMMA nanocomposites (84 ± 6 MPa) at 3 wt% zirconia was significantly greater than that of the control group (72 ± 9 MPa) (p < 0.05). The mean flexural modulus was also significantly improved with different concentrations of zirconia when compared to the control group, with 5 wt% zirconia demonstrating the largest (23%) improvement. The mean fracture toughness increased in the group containing 5 wt% zirconia compared to the control group, but it was not significant. However, the median impact strength for all groups containing zirconia generally decreased when compared to the control group. Vickers hardness (HV) values significantly increased with an increase in ZrO2 content, with the highest values obtained at 10 wt%, at 0 day (22.9 HV0.05) in dry conditions when compared to the values obtained after immersing the specimens for seven days (18.4 HV0.05) and 45 days (16.3 HV0.05) in distilled water. Incorporation of ZrO2 nanoparticles into high impact PMMA resin significantly improved flexural strength, flexural modulus, fracture toughness and surface hardness, with an optimum concentration of 3–5 wt% zirconia. However, the impact strength of the nanocomposites decreased, apart from the 5 wt% zirconia group.

Augmented optical and electrical properties of PMMA-ZnS nanocomposites as emissive layer for OLED applications

We report the laboratory synthesis of Poly methyl methacrylate (PMMA)-Zinc sulfide (ZnS) nanocomposite via free radical polymerization method and its structural, optical, electrical, and dielectric properties for various concentration of ZnS nanoparticles. The formation of PMMA, ZnS and PMMA-ZnS nanocomposites was examined by X-ray diffraction technique, Fourier transforms infrared spectroscopy and FT-Raman spectrometer. Morphological structure of PMMA-ZnS nanocomposites showed the combination of pebbled and nanosphere like structure. The in-depth topological images were examined by transmission electron microscopy which indicated that the particles were fairly in good contact. The optimized and reduced band gap was calculated ∼3.30 eV. The photoluminescence spectra showed blue, green and yellow band with increased rate of e−-h+ recombination. The decay time of the PMMA-ZnS (5.0%) nanocomposite was ∼4.8413 ns, and the color purity was calculated ∼ 34.08%. The current density increased ∼249% which indicated the enhancement in conductivity. The dielectric properties of the PMMA-ZnS (5.0%) showed high dielectric constant with a very low dielectric loss. The reduction in optical band gap, high dielectric constant, and increased conductivity with increased in recombination rate confirmed that the as-prepared PMMA-ZnS nanocomposite can be used as an emissive layer in OLED devices.

Tribological and Mechanical Characteristics of Dental Fillings Nanocomposites

Dental fillings nanotechnology considers a significant and increasingly in need to obtain the best and stable dental fillings with excellent performance and long life. Tribological and mechanical characteristics of poly methyl methacrylate (PMMA) nanocomposites reinforced by nanoparticles of Titania (40% TiO2) and Calcium aluminate (60% CaAl2O4) in terms of different volume fractions ( 1 Vol.% - 5 Vol.%) have been studied. Ultrasonic dispersion technique used to prepare the nanocomposites specimens followed by cold – casting technique using flash Teflon molds according to standard conditions. Pin-on-disc technique is used to measure wear coefficient and coefficient of friction. Tribological tests of specimens were conducted at temperature 37°C and in the environment of artificial saliva. Hardness, compressive strength, Young modulus, and toughness have been measured according to ASTM standards. Results of tribological tests were led to improve the coefficient of friction and to decrease the wear coefficient with increasing of volume fraction and increase with slide lifetime, especially for 5 Vol. % specimens. Results of mechanical properties show that the values were increased progressively by succession of volume fraction of fillers. Simulation programs of tribological and mechanical tests for (TiO2 + CaAl2O4) / PMMA nanocomposites were carried out using finite difference method. The program was written in FORTRAN90 language using a computer type HP Pavilion g. The program assumes a load is directed towards a specimen of the composites. Density and optical microscope images were employed to aid interpretation of results. The results of study were reached that the optimum volume fraction was 5 Vol. %.

Synthesis and investigation of thermal properties of PMMA-maleimide-functionalized reduced graphene oxide nanocomposites

Reduced graphene oxide (RGEO) and N-[4-(chlorocarbonyl)phenyl]maleimide-functionalized reduced graphene oxide (MFRGEO) were used as nanofillers for polymethyl methacrylate (PMMA) matrix nanocomposites to enhance thermal stability. Methyl methacrylate containing nanofiller of four different weight percent (0.2, 0.4, 0.6, and 0.8) was polymerized using ultrasonic radiation-assisted bulk polymerization. The Fourier-transform infrared spectra showed the absence of chemical interaction between the filler and the matrix phase. Morphology of nanocomposites studied using scanning electron microscope confirmed the assistance aided by ultrasonication in the uniform dispersion of nanofiller in the PMMA matrix. Thermogravimetric (TG) study revealed the presence of MFRGEO enhanced the thermal stability of PMMA by shifting the entire degradation to higher temperature. The thermal stability of PMMA nanocomposite was improved by as much as 40°C at just 0.8 wt% loading of MFRGEO. Differential TG study also supported the role of maleimide functionalization on RGEO in the enhancement of thermal stability of PMMA by means of retarding the degradation rate of unsaturated chain ends in the PMMA matrix. Unlike MFRGEO, RGEO failed to enhance the thermal stability of PMMA.

Effect of Functionalized MWCNT on the Mechanical and Dielectric Properties of PMMA Nanocomposites

Carbon nanotubes (CNTs) are widely explained in fundamental blocks of nanotechnology. These CNTs exhibit much greater tensile strength than steel, even almost similar to copper, but they have higher ability to carry much higher currents, they seem to be a magical material with all these mentioned properties. In this paper, an attempt has been made to incorporate this wonder material, CNT, (with varying percentages) in polymeric matrix (Poly methyl methacrylate (PMMA)) to create a new conductive polymer composite. Various mechanical tests were carried out to evaluate its mechanical properties. The dielectric properties such as dielectric loss and dielectric constant were evaluated with the reference of temperature and frequency. The surface structures were analyzed by Scanning Electron Microscope (SEM).

Morphological and Tribological Properties of PMMA/Halloysite Nanocomposites.

From an environmental and cost-effective perspective, a number of research challenges can be found for electronics, household, but especially in the automotive polymer parts industry. Reducing synthesis steps, parts coating and painting, or other solvent-assisted processes, have been identified as major constrains for the existing technologies. Therefore, simple polymer processing routes (mixing, extrusion, injection moulding) were used for obtaining PMMA/HNT nanocomposites. By these techniques, an automotive-grade polymethylmethacrylate (PMMA) was modified with halloysite nanotubes (HNT) and an eco-friendly additive N,N′-ethylenebis(stearamide) (EBS) to improve nanomechanical properties involved in scratch resistance, mechanical properties (balance between tensile strength and impact resistance) without diminishing other properties. The relationship between morphological/structural (XRD, TEM, FTIR) and tribological (friction) properties of PMMA nanocomposites were investigated. A synergistic effect was found between HNT and EBS in the PMMA matrix. The synergy was attained by the phase distribution resulted from the selective interaction between partners and favourable processing conditions. Modification of HNT with EBS improved the dispersion of nanoparticles in the polymer matrix by increasing their interfacial compatibility through hydrogen bonding established by amide groups with aluminol groups. The increased interfacial adhesion further improved the nanocomposite scratch resistance. The PMMA/HNT-EBS nanocomposite had a lower coefficient of friction and lower scratch penetration depth than PMMA/HNT nanocomposite.

Effect of polyaniline‐coated carbon nanotube and nanosilver hybrid nanoparticles on the dielectric properties of poly(methyl methacrylate) nanocomposites

The polyaniline (PANI)‐coated functionalized multi‐walled carbon nanotubes (f‐CNTs) and silver nanoparticles (AgNPs) (PANI@f‐CNTs and PANI@AgNPs hybrid nanofillers) are synthesized by means of in situ polymerization of aniline monomer on the surface of f‐CNTs and AgNPs. The PANI@f‐CNTs and PANI@AgNPs hybrid nanofillers were successfully incorporated into the polymethyl methacrylate (PMMA) matrix through in situ polymerization of methyl methacrylate. The Fourier transform infrared spectroscopy analysis reveals that the existence of strong interfacial adhesive bonding between PANI@f‐CNTs and PANI@AgNPs hybrid nanofillers and PMMA matrix. The X‐ray diffraction (XRD) analysis indicates that there is no change in position of the diffraction peak as a result crystallinity of the samples are not much affected by the addition of hybrid nanofillers. The transmission electron microscopy and scanning electron microscopy analysis displayed that the phase morphology of the PMMA nanocomposites is significantly changed as well as hybrid nanofillers are homogeneously dispersed within the PMMA matrix. The AC conductivity (σac), dielectric permittivity (ɛ′) dielectric loss (tan δ) of the PMMA nanocomposites are remarkably increases whereas the real impedance (Z′) decreases by the Incorporation of the hybrid nanofillers into the PMMA matrix, which concludes that the synthesized polymer materials have most promising dielectric application. POLYM. COMPOS., 39:E1294–E1305, 2018. © 2018 Society of Plastics Engineers

Fabrication of γ-MPS-Modified HNT–PMMA Nanocomposites by Ultrasound-Assisted Miniemulsion Polymerization

Halloysite nanotubes (HNTs) were modified with γ-methacryloxypropyltrimethoxysilane (γ-MPS) to improve their interaction with the polymer, and the modified HNTs (MHNTs) were subsequently used for the synthesis of MHNT–polymethylmethacrylate (PMMA) nanocomposites by miniemulsion polymerization assisted by ultrasound. Reduced agglomeration of HNTs due to modification with γ-MPS was evident from scanning electron microscopy analysis. Modification of HNTs and exfoliation of MHNTs in the polymer nanocomposite were confirmed by the presence of their respective characteristic peaks in Fourier-transform infrared spectra and x-ray diffraction patterns. Transmission electron microscopic analysis showed that the surface of the MHNTs differed significantly from that of unmodified HNTs. MHNT–PMMA nanocomposite exhibited significantly higher glass-transition temperature (Tg) compared with neat PMMA or unmodified HNT–PMMA nanocomposite. Hence, such modification of HNTs along with miniemulsion polymerization assisted by ultrasound is a promising approach to achieve better dispersion of HNTs in the polymer and to obtain nanocomposites with enhanced properties.

Processing of PMMA nanocomposites containing biocompatible GO and TiO2 nanoparticles

ABSTRACTThe present study addresses the synthesis and characterization of polymethyl methacrylate (PMMA)/graphene oxide (GO) and PMMA/GO + TiO2 nanocomposites for potential application as dental materials. PMMA/0.0025 wt% GO and PMMA/0.0025 wt%GO + 1 wt% TiO2 were processed using twin-screw extrusion including melt compounding. The mechanical, thermal, and microstructural behaviors of nanocomposites were determined and compared with pure PMMA. The results of this work revealed that PMMA nanocomposites are potential candidates as dental materials.

An Investigation on Transparency and Mechano-Acoustic Properties of Poly Methyl Methacrylate/Polycarbonate Based Nanocomposites

The main goal of this paper was to investigate transparency and mechano-acoustic properties of poly methyl methacrylate (PMMA)/polycarbonate (PC) based nanocomposites, reinforced with silica (SiO2), zinc dioxide (ZnO), and titanium dioxide (TiO2) nanoparticles. For this purpose, morphological, transparency, acoustical and mechanical tests were carried out on the specimens, prepared by melt-compounding method in a twin-screw extruder. The morphological test results confirmed uniform dispersion of the nanoparticles in the polymer matrix. The results also revealed that transparency of the PC and PMMA nanocomposites, characterized by the degree of light transmittance, was decreased by adding 0.3 wt% of the nanoparticles. Also, tensile modulus of the nanocomposite specimens was higher than that of neat PC and PMMA. Unlike the neat PC specimens, tensile strength showed a decrease in PMMA specimens. The presence of nanoparticles in the composites decreased mobility of polymer chains and consequently, reduced elongation at break in the specimens. After surface roughening process, noise absorption coefficient in PC/PMMA nanocomposite specimens (PCSI3-R, PMSI3-R, and PMZN3-R) showed a higher absorption coefficient than the other specimens in the dominant frequency of traffic noise (500 Hz). As conclusion, roughening the surface of materials would be one of the most important factors enhancing the absorption coefficient of some of the nanocomposites in the middle frequency. The rough surface of particles in the base matrix increases the absorption coefficient of the materials, especially in the frequency of 500 Hz, as the dominant frequency of noise traffic. The suggested materials are predestinated to be appropriate in building industry, particularly in the structure of noise barriers.