PMMA Composites Research Articles

Influences of NBR/Al<sub>2</sub>O<sub>3</sub>/YSZ as Fillers for PMMA Composite on the Thermal Properties

The aim of this study is to investigate the effect of nitrile butadiene rubber (NBR as impact modifier) together with Al2O3/YSZ (toughening) as different filler ratios in PMMA material on the DSC thermal properties. PMMA matrix without fillers was mixed between PMMA powder and 0.5 wt.% of BPO and fixed at 7.5 wt.% of NBR particles with different ratios of filler (1, 3, 5, 7 and 10 wt.%) of Al2O3/YSZ mixture filler by (1:1 ratio). The TGA data were shown that the PMMA composite have better thermal stability compared to unreinforced PMMA matrix. While, DSC curves shows slightly similar in Tg value. DSC results also indicated the presence of unreacted monomer content for both reinforced and unreinforced PMMA composites. As conclusion of this study, the reinforced PMMA composites are improved in thermal stability compared to unreinforced PMMA matrix.

Physical, mechanical, thermal, and dynamic characterization of carbon nanotubes incorporated poly(methyl methacrylate)-based denture implant

The objective of this study was targeted to synthesize and characterize a carbon nanotubes (CNTs) incorporated poly(methyl methacrylate) (PMMA)-based denture polymer. Two experimental denture base polymers were fabricated either by incorporating single-walled CNTs (SWCNTs) (SW-group) or multi-walled CNTs (MWCNTs) (MW-group). In both groups, 0.5 wt% of the CNTs were incorporated into MMA monomer. Using a commercially available heat-cured PMMA (Interacryl Hot, Interdent, Opekarniska, Slovenia), a polymer-to-monomer ratio of 3:1 was used to fabricate the specimens (14 × 14 × 3 mm3 in dimensions) of the control group (without CNTs) (C-group) and the experimental groups (either SWCNT–PMMA or MWCNT–PMMA) ( n = 30, N = 90). Physical, mechanical, thermal, and rheological attributes of the tested materials were assessed. The data were statistically analyzed using SPSS version 21.0 (SPSS®, Chicago, IL, USA) and results were explored with one-way ANOVA. Incorporation of CNTs changed the surface morphology and topography of the PMMA specimens. No thermal changes were observed among C-, SW-, and MW-groups. Conversely, the hardness, elastic modulus and wear resistance were improved in both SW-group and MW-group. Additionally, the dynamic mechanical analyzer showed improvement in storage modulus in SW-group, affirming the load transfer capability of SW–PMMA composite. The CNT–PMMA composite might favorably be used as a potential denture base polymer.

Effect of Phase Selective Localization of Silica on Mechanical Properties of Polymethyl Methacrylate/Ethyl Vinyl Acetate/Silica Composites

SummaryPhase selective localization of silica in polymethyl methacrylate/ ethyl vinyl acetate (PMMA/EVA) composite controls the concentration of silica in each PMMA and EVA phases and affects the mechanical properties of the composite. In order to produce the different concentration of silica in each polymer phase, pre‐dispersion of silica into single phase of PMMA and EVA was carried out by using twin screw extruder and heated two rolls mill, respectively. The pre‐dispersed mixture then was compounded with the other polymer by using a twin‐screw extruder and produced PMMA/EVA composites. Conventional method by adding of silica into PMMA/EVA blend was also carried out as control sample. Distinguished morphologies were obtained from different processing, which induced significant effect on mechanical properties of these pre‐dispersed composites. Observation from SEM result, EVA exhibited rod morphology in control composite but more spherical morphology in pre‐dispersion composites. It is assumed that higher concentration of silica in PMMA phase resulted in the optimum mechanical strength of pre‐dispersion of silica in PMMA composites compared to others. In addition, composite prepared by conventional method also showed the lowest mechanical properties.

Synthesis and characterization of transparent erbium–ytterbium co‐doped polymer nanocomposites for fabrication of polymer optical preform

Synthesis of polystyrene (PS) and poly (methylmethacrylate) (PMMA)‐grafted Er–Yb co‐doped transparent ternary nanocomposite is presented herein. Er–Yb co‐doped nanoparticles (NP) were synthesized from their nitrate precursors followed by surface modification using 3‐methacryloxypropyltrimethoxysilane (MPS) as surfactant. In situ polymerization of methylmethacrylate (MMA) was performed in presence of benzoyl peroxide as initiator in toluene. The synthesized NP–PMMA composite was blended with PS in tetrahydrofuran (THF). Different material characterizations of synthesized composite were performed to evaluate shape, size and chemical nature of developed composite. UV–visible spectra and DLS technique revealed that optimum particle size in the range of <25 nm is essential to achieve optical transparency of developed composite. Refractive index of synthesized composite was also measured (RIcore > 1.5 at 589 nm) and indicate their potential application as active core material for preparation of rare earth doped polymer optical preform (POP). The POF preform prepared using commercially available cladding tube containing Er–Yb transparent polymer nanocomposites as core material is found to have numerical aperture around 0.19. The photoluminescence (PL) spectrum was also measured and intensity of Er–Yb co‐doped composite found to be ten times greater than pure Er‐doped system.

The preparation and characteristic of maleic anhydride grafted polyethylene (PE-g-MA) filled CNT/PMMA composite film

ABSTRACTIn order to improve the tribological properties of PMMA, the PMMA composites incorporated with CNT powders were prepared. The effect of CNT content on tribological properties of the composites was investigated. When CNT content is 0.5 wt%, the friction coefficients of the 0.5%CNT/PMMA composite are the smallest, which are about 0.15 and are 67% less than those of the pure PMMA composite, and its wear resistance remains the same as the pure PMMA composite. Incorporating 0.5 wt% CNT into the PMMA composite may develop a continuous transferred film on the worn surface. As a result, the friction coefficients of the composite are reduced and its wear mechanism is mainly fatigue spalling. The addition of PE-g-MA improved the friction and wear properties of CNT/PMMA composite.

Studies on the Surface Properties of PMMA after Accelerated Weathering

The surface properties of poly(methyl methacrylate) (PMMA) were investigated after accelerated weathering. Glossinesses, contact angles, surface free energies, thermal stability, and mechanical properties were investigated. The glossiness of the weathered PMMA was decreased with increasing exposure time. Contact angles and surface free energies were not overtly changed because the amount of oxygen on the surface was remained. PMMA was compounded with anti-block and antistatic agents using a co-rotating twin screw extruder to improve the durability. The PMMA composites showed better glossinesses after accelerated weathering while maintaining the contact angles, surface energy, thermal stability, and mechanical properties without significant changes.

Thermomechanical properties and thermal degradation kinetics of poly(methyl methacrylate) (PMMA) and polycarbonate (PC) filled with cerium-doped yttrium aluminium garnet (Ce:YAG) prepared by melt compounding

This paper reports on the thermomechanical properties and thermal degradation kinetics of poly(methyl methacrylate) (PMMA) and polycarbonate (PC) composites filled with cerium-doped yttrium aluminium garnet (Ce:YAG) at different contents ranging between 0.1 and 5 wt%, and prepared by melt compounding. The interaction between PMMA and the filler was much stronger than that between PC and the filler, and this resulted in a significant improvement in the dynamic mechanical properties of the PMMA composites. The presence of filler did not significantly increase the thermal stability of the PC, while an observable increase in the thermal stability was only observed at higher filler loadings for the PMMA composites. This was attributed to the stronger interaction between Ce:YAG and PMMA and/or its degradation volatiles.

Optical Properties of PMMA Composites Prepared by Extrusion Processing for Light Emitting Diode Light Diffuser Covers

Optical Properties of PMMA Composites Prepared by Extrusion Processing for Light Emitting Diode Light Diffuser Covers

Conductivity of melt spun PMMA composites with aligned carbon fibers

The conductivity and morphology of melt-spun PMMA/carbon fiber (CF) composites have been investigated and analyzed. Using a two-step melt mixing procedure, CF aspect ratios of 6.3, 9.2 and 12.0 were achieved. Fiber composites with different CFs concentrations were melt spun using a capillary rheometer, to induce CF orientation, and the morphologies of both the surface and the cross-section were observed and discussed. The conductivity of composite fibers at room temperature was compared with the McLachlan GEM equation and Balberg excluded volume theory. The percolation threshold as well as the relationship between the percolation behavior and the aspect ratio were also determined. Taking into consideration the filler orientation, the slope K = 3.4 in excluded volume theory was estimated for the first time.

Influence of carbon nanotubes functionalization on the mechanical properties of polymethacrylate nanocomposites

Nanocomposites based on poly (methyl methacrylate) (PMMA) and a copolymer of methyl methacrylate and hexyl methacrylate were investigated. The fillers were: multi walled carbon nanotubes (MWCNTs) and functionalized MWCNTs (oxidized). The samples were studied by the depth sensing indentation methods (DSI) based on measurement of load–displacement curves at a constant loading speed. The tests were performed on a dynamic ultra microhardness tester DUH-211S in accordance with ISO 14577-1. The dynamic hardness, Martens hardness, indentation hardness, indentation modulus and elastic part of the deformation work were measured. Classical Vickers hardness was also determined.It was established that the mechanical properties of the polymer matrices have been improved by adding 1% of MWCNTs in spite of their being or not functionalized. The presence of functionalized nanotubes had a particular effect upon the different polymer composites. They improved the micromechanical characteristic for PMMA composites and worsened those of copolymer composites. The following assumptions about the structural peculiarities of the composites investigated have been proposed: the reason for the different effect of the modified carbon nanotubes are the length of the side chains and different interaction; the long hexyl groups spatially hinder the contact of the ester groups with functionalized MWCNTs and thus facilitate the agglomeration of the latter.

Preparation and characterization of lithium ion conducting polymer electrolytes based on a blend of poly(vinylidene fluoride-co-hexafluoropropylene) and poly(methyl methacrylate).

Ion conducting polymer electrolytes composed of poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), poly(methyl methacrylate) (PMMA) and lithium triflate (LiTf) were prepared using the solution casting method. Structural change and complex formation in the blend electrolyte systems were confirmed from the X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) studies. Thermal properties of the samples were investigated by the differential scanning calorimetry (DSC) technique. The ionic conductivity of these polymer electrolytes was studied by impedance spectroscopy at various temperatures ranging from 303–393 K. The results reveal that the ionic conductivity of the polymer blend electrolytes depends on the PVdF-HFP:PMMA composition as well as the temperature. Maximum room temperature conductivity of S cm−1 was achieved with 22.5 wt.% PMMA. The blending of PVdF-HFP with PMMA improved the thermal stability and ionic conductivity of the polymer electrolyte. Estimated transference numbers suggest the charge transport is predominantly ionic.

Evaluation of the Mechanical and Radiopacity Properties of Poly(Methyl Methacrylate)/Barium Titanate-Denture Base Composites

This study aimed to evaluate the flexural and hardness properties of poly(methyl methacrylate) (PMMA) denture base filled with barium titanate (BaTiO3). The baTiO3 filler was treated with 3-trimethoxysilylpropyl methacrylate, which is a silane coupling agent. Curing was performed in a water bath at 78 °C for 1.5 h. The samples were tested for tensile and flexural strength and surface hardness. The samples were also radiographed, and their optical densities were determined. Radiopacity values were compared with that of an aluminium (Al) plate with equivalent thickness. A reduction in the tensile and flexural strength of the PMMA composite was observed at high filler loadings. However, the surface hardness of the denture base composites was enhanced as a function of filler loading. The radiopacity of the PMMA/BaTiO3 composites was also improved. Adding 10 wt.% of baTiO3 to PMMA resulted in a higher optical density (OD) (p< 0.07) compared with that of Al.

Immobilization of nanomaterials in PMMA composites for photocatalytic removal of dyes, phenols and bacteria from water

Nanomaterials represent a possible solution to solve many of the current issues involving water quality, but several limitations exist for efficient applications, primarily concerning the dispersion of such nanomaterials in water, their recovery after water treatment and the resulting impact on human health and ecosystems. We present an approach based on the incorporation of several nanomaterials into polymeric composites as a valid solution to overcome these problems. We embedded active TiO2 nanostructures in poly (methyl methacrylate) (PMMA), with the advantage of no need of recovery of the nanoparticles after water treatment. Furthermore, we combined titanium dioxide nanoparticles with single walled carbon nanotubes, as acceptor of electrons, and obtained a significantly higher photocatalytic efficiency under UV irradiation, compared to the systems with TiO2 only. Photoactive materials even under visible light were synthesized thanks to the functionalization of the TiO2 nanoparticle surface with meso-tetraphenylporphyrin-4,4′,4′′,4′′′-tetracarboxylic acid (TCPP) as dye sensitizer. We realized these polymeric nanocomposites by low-cost solution casting and evaluated their photocatalytic activity by degradation of some dyes and phenol in an aqueous medium. A significant antibacterial activity, measured through CFU (colony forming units) count using Escherichia coli as a model organism, is also reported.

High transparency and toughness PMMA nanocomposites toughened by self-assembled 3D loofah-like gel networks: fabrication, mechanism, and insight into the in situ polymerization process

Novel transparent PMMA composites were toughened with 3D loofah-like gel networks obtained via in situ polymerization of methyl methacrylate gel with POSS-based supramolecular POSS-Lys(BOC) gelators.

Length-dependent broadband electric properties of PMMA composites filled with carbon nanotubes

Broadband dielectric/electric properties of multiwalled carbon nanotubes (MWCNT) polymethylmetacrylate composites were studied in a wide temperature range (25–400 K). It was established that the percolation threshold is lower in composites with the shortest MWCNT, due to the better distribution of the MWCNT in the polymer matrix. The value of the dielectric permittivity and the electrical conductivity below the percolation threshold is also higher in composites with the shortest MWCNT. Below the percolation threshold the dielectric dispersion in composites is mainly related with the β relaxation in the polymer matrix. The length of the MWCNT and its concentration have also the huge influence on polymer matrix molecular dynamics, the relaxation time is shortest in composites with the higher MWCNT concentration and in composites with the shortest MWCNT. At low temperatures the conductivity of composites above the percolation threshold is governed by an electron tunneling between MWCNT clusters. At higher temperatures the electrical transport occurs also due to the finite electrical conductivity of the polymer matrix.

Modification of nanocrystalline cellulose for application as a reinforcing nanofiller in PMMA composites

Nanocrystalline cellulose (NCC) with particle length of 100–500 nm was prepared from microcrystalline cellulose and modified with a reversible addition–fragmentation chain transfer (RAFT) agent, i.e., 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid (CPADB). From the surface of CPADB-modified NCC, methyl methacrylate (MMA) was grafted to produce poly(methyl methacrylate) (PMMA)-modified NCC. Unmodified NCC, CPADB-modified NCC, and PMMA-modified NCC were further used as reinforcing nanofillers in PMMA composite plates prepared by bulk polymerization of MMA. Regardless of NCC type, the PMMA plates were transparent to visible light at low NCC concentrations but became translucent with increasing NCC concentration. At given NCC concentration, the visible-light transparency of the PMMA/NCC composites decreased in the order PMMA-modified NCC, CPADB-modified NCC, unmodified NCC. PMMA-modified NCC and CPADB-modified NCC showed moderate potential for reinforcing the PMMA matrix, while unmodified NCC detrimentally affected the mechanical properties of the PMMA composites due to more pronounced particle aggregation.

Highly selective removal of poly(methyl methacrylate) from polystyrene-block-poly(methyl methacrylate) by CO/H2 plasma etching

The directed self-assembly lithography process using polystyrene (PS)-block-poly(methyl methacrylate) (PMMA) requires selective removal of PMMA, which is called the development process. The development process using plasma etching (dry development) without surface roughness of the line/space pattern was investigated. First, the authors focused on the chemical compositions of PMMA and PS. Using CO plasma, highly selective etching of PMMA was achieved (PMMA/PS etch selectivity >20). It was found that the PS surface roughness induced by plasma treatment depended on the thickness of the deposition layer formed on the PS surface. To suppress the PS surface roughness because of plasma treatment, the authors controlled the thickness of the deposition layer by adding H2 gas to the CO plasma. Using CO/H2 plasma, highly selective PMMA/PS etching without surface roughness was achieved. Consequently, the authors successfully achieved dry development of random lamella patterns by application of the CO/H2 plasma process.

Achieving large dielectric property improvement in polymer/carbon nanotube composites by engineering the nanotube surface via atom transfer radical polymerization

High dielectric constant (high-k) polymer composites have many applications in electrical insulation and energy storage systems because of their ease of processing. An important route to high-k polymer composites is to introduce high-aspect-ratio conductive nanoparticles (e.g., carbon nanotubes, CNTs) into a dielectric polymer. However, it is difficult to tune the dielectric properties of the composites via only adjusting the nanoparticle loading, particularly when the conductive nanoparticle concentration is near the percolation threshold. In this work, by using surface-initiated atom transfer radical polymerization, poly(methyl methacrylate) encapsulated CNTs (PMMA@CNTs) were prepared and used to tune the dielectric properties of PMMA composites. It was found that the PMMA@CNTs can be well dispersed into the PMMA matrix, regardless of the thickness of the PMMA shell grafted onto the CNT surface. The electrical parameters of the composites, such as percolation threshold, electrical conductivity, dielectric constant and dielectric loss tangent, can be tuned by controlling the thickness of the PMMA shell on the CNT surface. High dielectric constant and low dielectric loss can be achieved by adjusting the loading of PMMA@CNTs and the thickness of the PMMA shell on the CNT surface.

The use of different alumina fillers for improvement of the mechanical properties of hybrid PMMA composites

Abstract Alumina fillers having different morphologies were used for reinforcement of PMMA-based composite materials. The employed fillers had the same chemical composition but morphologically were spherical nanoparticles, whiskers and an electrospun product that was composed of micro-sized mostly spherical particles and nanofibers. The electrospun product was obtained from aluminum chloride hydroxide/PVA/water solution. All fillers were added without surface treatment and mechanical characteristics of obtained composites were determined using dynamic mechanical analysis (DMA) and nanoindentation. From the nanoindentation results, the reduced elastic modulus for the obtained specimens using 3 wt.% of electrospun product was 134% of the one obtained with the polymer alone and the hardness was improved to 157.8% compared to the polymer without any additive. DMA shows that the storage modulus at room temperature was twice that of the polymer alone.

Effects of Manufacturing Technology on the Mechanical Properties of Alfa Fiber Non-woven Reinforced PMMA Composites

Mechanical properties of nonwoven alfa fiber based reinforced biocomposite were evaluated to assess the possibility of using it as a new material in engineering applications such as orthopedic application. Samples were fabricated by needle punching, thermal bonding and Hydroentanglement, by blending alfa fibers with wool fibers or Polypropylene fibers. The mechanical properties were tested and showed that the nonwoven NW3 (alfa fiber/PP/PLA, with hydroentanglement) is the best. It has a value of stress at break of 1.94 MPa, a strain of 54.2% and a young’s module of 7.95 MPa, in a production normal direction. A biocomposite has been made with NW3 mixed with PMMA matrix. The use of nonwoven based alfa fiber in reinforcing the composite material increases its rigidity and the tensile strength; the elongation was found to be 1.53%, the Young’s Module of 1.79 GPa and the tensile at break of 15.06 MPa. Results indicated that alfa fibres are of interest for low-cost engineering applications and can compete with glass fibres in orthopedic application.