Polymethylmethacrylate nanoparticles

Preparation of nanoparticles can be by a variety of different ways. The most important and frequently used is emulsion polymerization others include interfacial polymerization, solvent evaporation, and desolvation of natural proteins. The materials used to prepare nanoparticles are also numerous, but most commonly they are polymers such as poly-alklcyanoacrylate, polymethylmethacrylate, poly-butylcyanoacrylate, or are albumin or gelatin. Distribution patterns of the particles in the body can vary depending on their size, composition, and surface charge [83-85]. In particular, nanoparticles of polycyanoacrylate have been found to accumulate in certain tumors [86,87]. 

Kreuter and Speiser [77] developed a dispersion polymerization producing adjuvant nanospheres of polymethylmethacrylate) (PMMA). The monomer is dissolved in phosphate buffered saline and initiated by gamma radiation in the presence and absence of influenza virions. These systems showed enhanced adjuvant effect over aluminum hydroxide and prolonged antibody response. PMMA particles could be distinguished by TEM studies and the particle size was reported elsewhere to be 130 nm by photon correlation spectroscopy [75], The particle size could be reduced, producing monodisperse particles by inclusion of protective colloids, such as proteins or casein [40], Poly(methylmethacrylate) nanoparticles are also prepared... 

Synthesis and characterization of CdS nanoparticles embedded in a polymethylmethacrylate matrix was presented [165]. The assembly of CdS semiconductor nanoparticle monolayer on Au electrode was obtained, and its structural properties and photoelectrochemical applications were studied [166]. 

The first step was to spin-coat an electron-sensitive polymer (polymethylmethacrylate (PMMA)) onto an oxidized Si(l 00) wafer (which serves as a Si02 support). The desired pattern is subsequently written into the polymer layer by a highly collimated electron beam, followed by the selective dissolution of the polymer damaged by the electron exposure. A thin film of platinum is then deposited on this mask, and after the remaining polymer resist is removed completely by dissolution, metal particles remain on the substrate and are located at the positions of the prior electron irradiation, typically forming an ordered array of nanoparticles. 

A few other ceramic nanoparticles have been studied to date for orthopedic applications, most of which, however, are used as additives to other orthopedic materials. For example, bare or functionahzed magnesium oxide, zirconia, barium sulfate, and calcium carbonate are added to polymethylmethacrylate (PMMA) bone cement to reduce the exothermic effect of PMMA while increase its cytocompatibility. X-ray radiopac-ity, as well as antibacterial potential [65],... 

Polyaniline-ZnO nanocomposites were synthesized by in-situ oxidative polymerization of aniline monomer in the presence of different amounts of ZnO nanostructures. ZnO nanostructures were prepared in the absence and presence of surfactant. The effect of ZnO nanostructure concentration on the conducting behaviour of nanocomposites was evaluated by a two-probe method. The results showed that the conductivity of nanocomposites was increased with an increased concentration of ZnO nanostmctures as compared with neat polyaniline. Optimum conductivity was observed with incorporation of 60% ZnO nanostructures into the polyaniline matrix [248].Polymethylmethacrylate-ZnO nanocomposites were fabricated by solution radical copolymerization of methyl methacrylate and oleic acid-modified ZnO nanoparticles using 2,2 -azobisisobutylonitile as initiator in toluene. The UV-vis analysis showed that resulting nanocomposites exhibited high absorption in the ultraviolet region and low absorption in the visible region [249]. 

Addition of nanoparticles results in less coalescence of particles during the melt processing, causing improved compatibilization. For example, exfoliated clay compatibilization, snch as in a polycarbonate/polymethylmethacrylate (PC/ PMMA) system, polyphenylene oxide/polyamide (PPO/PA), polyamide/ethyl-ene propylene diene elastomer (PA/EPDM) rnbber, polystyrene/polymethyl-methacrylate (PS/PMMA), and polyvinyl fluoride/polyamide-6 (PVF/PA) blends, is affected by lowering the interfacial tension between the two phases that are phase separated. 

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