Thermal Stability Of Polymethyl Methacrylate Research Articles

Optical and thermal properties of polymethyl methacrylate (PMMA) bearing phenyl and adamantyl substituents

Polymethyl methacrylate (PMMA) is a widely used optical polymer due to its excellent transparency and durability. However, the sole methyl group shows pure PMMA low refractive index and low UV absorbility, and poor thermal stability. In this work, two comonomers phenyl methacrylate (PhMA) and adamantyl methacrylate (AdMA) were used for copolymerization with methyl methacrylate (MMA), and three copolymers P(AdMA-co-MMA), P(PhMA-co-MMA) and P(AdMA-co-PhMA-co-MMA) were prepared. They were characterised by FTIR, 1H NMR, UV-Vis, ellipsometer, DSC, TG, and TG-MS, and the effects of phenyl and adamantyl substituents on the optical and thermal properties of PMMA were studied. It was found that phenyl played an important role in increasing the absorption and refraction of PMMA in the deep UV region (190–260 nm), while the glass transition temperature and thermal stability of PMMA were more affected by adamantyl than by phenyl. Introduction of phenyl and adamantyl substituents provided a method to tune the optical and thermal properties of PMMA as photoresist or antireflective coating for deep UV lithography.

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.

Influence of acrylamide monomer addition to the acrylic denture-base resins on mechanical and physical properties

The aim of the study was to evaluate the effect of adding acrylamide monomer (AAm) on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly(methyl methacrylate) (PMMA) denture-base resins. Specimens (n=10) were fabricated from a conventional heat-activated QC-20 (Qc-) and a microwave heat-activated Acron MC (Ac-) PMMA resins. Powder/liquid ratio followed the manufacturer's instructions for the control groups (Qc-c and Ac-c) and for the copolymer groups, the resins were prepared with 5% (−5), 10% (−10), 15% (−15) and 20% (−20) acrylamide contents, according to the molecular weight ratio, respectively. The flexural strength and flexural modulus were measured by a three-point bending test. The data obtained were statistically analyzed by Kruskal–Wallis test (α=0.05) to determine significant differences between the groups. The chemical structures of the resins were characterized by the nuclear magnetic resonance spectroscopy. Thermal stabilities were determined by thermogravimetric analysis (TGA) with a heating rate of 10 °C⋅min−1 from 35 °C to 600 °C. Control groups from both acrylic resins showed the lowest flexural strength values. Qc-15 showed significant increase in the flexural strength when compared to Qc-c (P<0.01). Ac-10 and Ac-15 showed significance when compared to Ac-c (P<0.01). Acrylamide incorporation increased the elastic modulus in Qc-10, Qc-15 and Qc-20 when compared to Qc-c (P<0.01). Also significant increase was observed in Ac-10, Ac-15 and Ac-20 copolymer groups when compared to Ac-c (P<0.01). According to the 1H-nuclear magnetic resonance (NMR) results, acrylamide copolymerization was confirmed in the experimental groups. TGA results showed that the thermal stability of PMMA is increased by the insertion of AAm.

Mechanical and thermal properties of denture PMMA reinforced with silanized aluminum borate whiskers

The aim of this study was to investigate the mechanical and thermal properties of denture polymethyl methacrylate (PMMA) reinforced with aluminum borate whiskers (ABWs). To improve bonding between ABWs and PMMA matrix, the surface of ABWs was modified with a silane coupling agent. Varied contents of silanized ABWs -ranging between 1 and 20 wt%- were mixed into the PMMA resin matrix to prepare ABW/PMMA composites, which were subjected to three-point bending test, Vickers hardness test, and thermal analysis. Silanized ABWs improved the flexural strength, surface hardness, and thermal stability of PMMA. Optimal amount of ABWs in the PMMA matrix was 5 wt%, which provided the ABW/PMMA with maximum reinforcement.

Analytical calculations and properties of γ-rays polymerization of novel acrylates copolymer system

A detailed study of some physical properties of pure PMMA (polymethyl methacrylate) film and MMA/Ani (methyl methacrylate/aniline) films is presented. Films of thicknesses ranged from 0.04 to 0.72 mm for MMA/Ani were prepared while it is 0.68 mm for PMMA. The structure of the sample is analyzed by X-ray diffraction technique and is found to be amorphous (PMMA) and partially crystalline (MMA/Ani). Ultra violet–visible electronic absorption spectra measurements were analyzed to obtain some important parameters such as molar extrication coefficient, oscillator strength, dipole strength and having good thermal stability ( T d >300 °C) was also reported. TGA studies revealed that the thermal stability of polymethyl methacrylate, prepared by radiation polymerization of methyl methacrylate, improved after copolymerization with aniline. Also, optical behavior of film samples was analyzed by obtaining transmission spectra, in the wavelength range of 200–1100 nm. It was found that all studied samples lead to the appearance of a second edge at lower photon energy due to the formation of the induced energy states. From the intensity of absorption interband transitions (B and Q) which are assigned as type π – π * for both PMMA and MMA/Ani films, the energy gaps E g 1 and E g 2 were calculated respectively. The optical conductivity ( σ ) was determined and it was found that with the increase of thicknesses optical energy gap decreases monotonically and the refractive index increases.

Effect of Nanoparticles on the Thermal Stability of Polymers

ABSTRACTThe thermal stability of polymethylmethacrylate loaded with silica nnaoparticles is investigated. The temperature dependence of the mass has been accurately fitted with a single Boltzmann-like dependence. The effect of surface functionalization, size of silica nanoparticles, and concentration of silica nanoparticles is analyzed. A weak increase of the thermal stability of polymethylmethacrylate has been obtained by loading the polymer matrix with nanoparticles. Surface functionalization produced a modest increase in the thermal stability (compared to composites with silica nanoparticles without surface modification).

Mass-spectrometric investigation of the thermal stability of polymethyl methacrylate in the presence of C60 fullerene

The thermal degradation of polymethyl methacrylate, synthesized by the method of free-radical polymerization, in a mixture with C60 fullerene has been investigated by mass-spectrometric thermal analysis. C60 suppresses the first two, low-temperature, stages in the thermal degradation of polymethyl methacrylate and thereby increases its thermal stability.

The effect of dicalcium silicate (C 2S) and tricalcium silicate (C 3S) on the thermal stability of vinyl-type polymer concrete

The effect of anhydrous cement on the thermal stability of vinyl-type polymer concretes has been studied by investigating the interaction between the polymers and the calcium compounds of cement. It was proven from differential scanning calorimetry that C 2S and C 3S have a significant effect on the thermal stability of polymethyl methacrylate and polystyrene. From infrared analysis, the reaction mechanism appears to occur between the calcium oxide in the filler and the -CH 2- groups in the polymer. Polymer concrete containing 17 wt% C 2S maintained excellent strength after exposure for 30 days to 25% brine solutions and to air at 238°C.