Polymethyl methacrylate films

Radical copolymerization of diaryl nitrones, such as a-(2-hydroxyphenyl)-A-(2,6-dimethylphenyl) nitrone (HDN), a-(2-hydroxy-4-methacryloyloxyphenyl)-N -(2,6-dimethylphenyl) nitrone (HMDN), and a-(2-hydroxy-4-methacryloyloxy-phenyl)-A-phenylnitrone (HMPN) (Fig. 2.30), with methyl methacrylate leads to copolymers in good yields with considerable quantities of hydroxy substituted diaryl nitrone pendants. The presence of photoactive nitrone pendants in these copolymers allows one to control photochemically the refractive index of polymethyl methacrylate films (468, 700, 701). 

Ma GB, Cheng WJ, Chen GH, Ming NB (2000) Orientation and photoluminescence of C-60 crystallites in C-60-polymethyl methacrylate films. Thin Solid Films 375 292-295. 

Ma GB, Yang YH, Chen GH (1998) Anomalous photoluminescence from C-60 polymethyl methacrylate films. Materials Letters 34 377-382. 

Figure 8.16. The volume fraction composition of polymethyl methacrylate films spread at the air/water interface for (a) isotactic PMMA and (b) syndiotactic PMMA (o, polymer A, water and +, air). After Henderson et al. (1991).

For the first study, polymethyl methacrylate films were spin coated onto silicon wafers, and the film thickness was determined using ellipsometry. A series of thin films were examined using techniques such as dielectric analysis and thermal mechanical analysis. The theory of cooperativity, which explains pol5mieric behavior using the intermolecular and intramolecular forces among polymer chains, was employed to understand the behavior of these thin films. 

They are atactic amorphous polymers which have good light transparency (92%) and yield transparent moldings and films. As was noted for polyalkyl acrylates, the solubility parameters decrease as the size of the alkyl groups increases. The flexibility also increases as one goes from polymethyl methacrylate (PMMA) to polyaryl methacrylate and then decreases as the size of the alkyl group is further increased. 

Figure 15. Influence of the Polyester Yellow dye film absorbance and polymer binder material on the marking threshold energy. PnBMA = poly(n-butyl methacrylate) PiBMA = poly(isobutyl methacrylate) PS = polystyrene PsBMA = poly (sec-butyl methacrylate) PVB = polyvinylbutyl PMMA = polymethyl methacrylate PVAC = polyvinylacetate, S-iBMA = poly(styrene-co-isobutyl methacrylate), PC = polycarbonate S-AN — poly(styrene-co-...

In investigating how Cooper pairs56 in a superconductor (Pb) may retain their coherence if they penetrated, across a thin tunneling gap (a film of polymethyl methacrylate, PMMA) into a conventional nonsuperconducting metal (Al), Jaklevic57 and Lambe58 discovered accidentally in 1966 that steps in the current, when displayed as the second derivative dzI/dVz versus V, were actually due to vibrations in polar molecules (IR) and also vibrations in... 

Literature continues to be rather extensive on this subject since the 1930s. A summarization is provided in this section. Products fabricated include sheets, films, rods and tubes, and embedment. Acrylic castings usually consist of polymethyl methacrylate (PMMA) or copolymers of this ester as the major component with small amounts of other monomers to modify the properties (Chapter 2). Adding acrylates or higher methacrylates lowers the heat deflection temperature and hardness and improves thermoformability and solvent cementing capability, with some loss in resistance to weathering. Dimethacrylates or other crosslinking monomers increase the resistance to solvents and moisture. 

Samples. Polyethylene terephthalate (PET) samples are industrial (Mylar) biaxially oriented films (10 pm thick). Polymethyl-methacrylate (PMMA) has been spin coated on microscope glasses from a PMMA (1) / CHjClj (9) solution, giving thin layers of a few hundred A thickness. 

Electron microscopy samples were prepared by techniques similar to that of Kato (8). Film samples were fixed with OSO4, potted in polymethyl methacrylate and then microtomed into thin sections ( 100 nm) for transmission examination using a Philips 100B electron microscope. 

For the remainder of this section, three examples illustrating the behavior predicted in Table 6.4 are discussed. Singer et al. (28) have extensively investigated field-induced alignment for the azo dye Disperse Red I in polymethyl methacrylate (PMMA). Using a dopant molecule number density of 2.74 X 10 /cm, they showed the reasonably linear behavior of Xxxx pohng field when the film was poled above its Tg and quenched in the... 

Film coating processes need the knowledge of the glass transitions for a proper film. Ethylcellulose, cellulose phthalate, polyvinylalcohols, polymethyl methacrylates have been studied and the critical parameters for film formation discussed. 

Radiochromic solids can be utilized and evaluated by visible spectrophotometry. Amber and red polymethyl methacrylate are used to evaluate 0.1-1.0 Mrad and 0.5-5.0 Mrad, respectively. Nylon film is examined for opacity following exposure and may be used to evaluate exposures of 0.1-5.0 Mrad. 

Tphe surface activity of block copolymers containing dimethylsiloxane units as one component has received considerable attention. Silicone-poly ether block copolymers (1,2,3) have found commercial application, especially as surfactants in polyurethane foam manufacture. Silicone-polycarbonate (4, 5), -polystyrene (6, 7), -polyamide (8), -polymethyl methacrylate (9), and -polyphenylene ether (10) block copolymers all have surface-modifying effects, especially as additives in other polymeric systems. The behavior of several dimethylsiloxane-bisphenol A carbonate block copolymers spread at the air—water interface was described in a previous report from this laboratory (11). Noll et al. (12) have described the characteristics of spread films of some polyether—siloxane block co-... 

The most widely used terms are acrylic add itse acrylamide, and, above all, acrylates and methacrylates. They are essentially used to manufacture polymers for many applications. inducting plastic films, molding powders, paint emulsions, etc. The most widely used polymer is polymethyl methacrylate (Plexiglas). 

The 200 to 400 nm spectral Irradlance Inside the CER was measured using a Gamma Scientific Spectroradlometer. A selenium photovoltaic cell and Corning 7-45 ultraviolet filter was used to monitor the UV Irradlance. A 1 x 2 cm silicon solar cell was used to measure the near-IR Irradlance. CER photon flux was also calibrated by using 0-nltrobenzaldehyde (0-NBA) as an actlnometer( ). Outdoor photon flux was measured by dispersing 0-NBA In thin films (25 urn) of polymethyl methacrylate. These films were then exposed at the outdoor site behind a neutral density filter and were examined on a weekly basis. Outdoor weekly UV photon flux was calculated based on the conversion rate of the 0-NBA. 

UV Screening Plastic Films. The module front cover Is In direct contact with all of the weathering elements UV, humidity, dew, rain, oxygen, etc. therefore, the selected materials must be weatherable. Only four classes of transparent materials are known to be weatherable, glass, fluorocarbons, silicones and polymethyl methacrylate. 

Candidates. The only commeroially available oriented films known at this time which fit the weather resistance requirements are polyvinylidene fluoride (PVF2)i polyvinyl fluoride (Tedlar), polymethyl methacrylate (PMMA), and polybutyl aorylate/methyl methacrylate copolymer (PBA/MMA). PVF2 is currently expensive. PBA/MMA is inexpensive but in clear form does not appear to be sufficiently oxidatively stable for our purposes. It is also too water sensitive and too easily softened in many laminating processes. PMMA appears to be somewhat more chemically stable than PBA/MMA and is also relatively Inexpensive, but has the same dimensional stability problems at 150°C, the normal pottant processing temperature. Both acrylics maintain excellent optical clarity on heat aging, however. 

Uses Flame retardant, plasticizer for PVC and copolymers, PVC plasti-sols, PVC textile coatings, PVAc, cellulosics, polymethyl methacrylate, PS, PP, engineering resins, unsat. polyester, alloys, clear films and sheets. Buna N rubber, acrylic, phenolics food-contact applies. Features Low smoke generation exc. low temp, props. improves processing due to exc. resin solvating power Reguiatory FDA approved for food contact use Properties Colorless clear liq. essentially odorless sol. in most org. soivs. m.w. 362 sp.gr. 1.090 (20/20 C) dens. 9.1 Ib/gal vise. 18 mPas vapor pressure 0.2 mm Hg (150 C) b.p. 462 F (10 mm, dec.) pour pt. -65.2 F flash pt. (COC) 435 F fire pt. (COC) 460 F ref. index 1.508-1.511 8.5% P Phosflex 390 [Akzo Nobel Hatwick Std. Distrib.]... 

Uses Flame retardant, plasticizer for PVC, cellulose nitrate, CAB, ethyl cellulose, polymethyl methacrylate, PS, buna N rubber, vinyl film and sheeting, textile coatings, plastisols, organosols, adhesives, pkg. materials, food-contact applies. 

Ethylene/tetrafluoroethylene copolymer thermoplastic, lacquers Cellulose acetate butyrate thermoplastic, photographic film Cellulose acetate butyrate thermoplastic, protective coatings Cellulose acetate butyrate thermoplastic, PS barrier coatings Polymethyl methacrylate thermoplasticity aid Elvax 40-W... 

Jing, B., Zhao, J., Wang, Y., Yi, X., Duan, H. Water-swelling-induced morphological instability of a supported polymethyl methacrylate thin film. Langmuir 26,7651-7655 (2010)... 

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