Electron microscopy methyl methacrylate

The desorganization by dilution of the periodic structures of block copolymers has been studied by electron microscopy after polymerization of the solvent66,70,71. Two types of solvents have been used styrene, which is the monomer for the soluble polystyrene block and which prevents any incompatibility between polymeric chains during polymerization of the monomer, and methyl methacrylate which allows the study of the effect of incompatibility between polymeric chains during polymerization of the solvent. 

The study by low-angle X-ray diffraction and electron microscopy of concentrated solutions of the copolymers in preferential solvents for polybutadiene (iso-prene, butadiene) or for poly(a-methyl styrene) (styrene, a-methylstyrene, methyl methacrylate, methylethyl ketone) and of copolymers in the dry state obtained by slow evaporation of the solvent from the mesophases have shown the existence of three types of structure hexagonal, lamellar, and inverse hexagonal depending upon the copolymer composition84,85. The factors governing the structural type and the structural parameters are the same as in the case of polystyrene-polybutadiene copolymers85. ... 

AB copolymers of isoprene and methyl methacrylate have been synthetized by Rossi205. A hexagonal structure formed by cylinders of polyisoprene in a matrix of poly(methyl methacrylate) has been demonstrated by low-angle X-ray diffraction and electron microscopy for copolymers containing about 30% of polyisoprene209. ... 

The polymers chosen for the initial stages of our studies were poly-(methyl methacrylate) and polystyrene. There were several reasons for this choice, the most important being (1) well-characterized, low-molecular-weight monodisperse samples of poly(methyl methacrylate) and polystyrene are readily available, or at least relatively easy to synthesize and (2) the poly (methyl methacrylate) /polystyrene system is especially amenable to study by scanning electron microscopy, as we... 

Suspensions of polypyrrole were prepared by the FeCls oxidation of pyrrole in an aqueous solution of methylcellulose (49). The product was dried and yielded films with conductivities of 0.2 S/cm. Scanning electron microscopy revealed globular polypyrrole embedded in the methylcellulose matrix. After several months, these suspensions remained stable with no detectable precipitation. Similarly, the electropolymerization of 3-methyl-thiophene in solutions of poly(methyl methacrylate) and poly(vinyl chloride) was reported (50, 51). 

Fig.l Sedimentation field-flow fractionation fractogram of 0.207- jLm poly (methyl methacrylate) aggregate series from which six cuts were collected and analyzed by electron microscopy. Experimental conditions field strength of 61.6 g and flow rate of 0.84 mL/min. [Reproduced with permission from H. K. Jones et. al. (1988) /. Chromatogr. 455 1 Copyright Elsevier Science Publishers B. V.]... 

Huelck, V. Thomas, D.A. Sperling, L.H. Interpenetrating polymer networks of poly(ethyl acrylate) and poly(styrene-co-methyl methacrylate). I. Morphology via electron microscopy and II. Physical and mechanical behavior. Macromolecules 1972, 5 (4), 340-348. 

The microstructure of this type of material was studied as early as 1952 by Fischer and Isenbarth (1). These authors demonstrated by thin section transmission microscopy that a two-phase microstructure was present in a number of materials available commercially for restoring tooth structure. In 1955 Helmcke reported similar findings with electron microscopic studies of fracture replicas (2, 3). Then in 1958, Smith examined at low magnification fracture surfaces in materials made from denture base polymers attention centered on a system of ridges concentric with a mirror region (4). In retrospect, this phenomenon was similar to that observed in one-phase samples of poly (methyl methacrylate) (5). Subsequently, in 1961, Smith showed that the microstruc-... 

Fibers of the control and selected chemically modified cottons were examined techniques of optical microscopy described previously.Ultra thin cross sections of the fibers were subjected to layer expansion by polymerization of methyl methacrylate and to solubility tests in 0.5 M cupriethylenediamine (cuene) and were examined by the techniques of transmission electron microscopy as previously reported.Scanning electron micrographs of fibers of selected samples before and after subjection to various solvents were also obtained. 

The properties of the linear material 7.27 and the network copolymer 7.28 have been studied by dynamic mechanical analysis, DSC, and transmission electron microscopy. Evidence was obtained for the formation of highly ordered micro-phase-separated superstructures in the solid state from the materials 7.27. The Cu(bipy)2 moieties appear to form ordered stacks, and this leads to thermoplastic elastomer properties. In contrast, the network structure of 7.28 prevents significant microphase separation [51-53]. By means of related approaches, dinuclear Cu helical complexes have also been used to create block copolymers by functioning as cores [54], and polymer networks have also been formed by using diiron(II) triple helicates as cores for the formation of copolymers with methyl methacrylate [55]. 

Poly(vinyl chloride) (PVC) homopolymer is a stiff, rather brittle plastic with a glass temperature of about 80°C. While somewhat more ductile than polystyrene homopolymer, it is still important to blend PVC with elastomer systems to improve toughness. For example, methyl methacrylate-butadiene-styrene (MBS) elastomers can impart impact resistance and also optical clarity (see Section 3.3). ABS resins (see Section 3.1.2) are also frequently employed for this purpose. Another of the more important mechanical blends of elastomeric with plastic resins is based on poly(vinyl chloride) as the plastic component, and random copolymers of butadiene and acrylonitrile (AN) as the elastomer (Matsuo, 1968). On incorporation of this elastomeric phase, PVC, which is ordinarily a stiff, brittle plastic, can be toughened greatly. A nonpolar homopolymer rubber such as polybutadiene (PB) is incompatible with the polar PVC. Indeed, electron microscopy shows... 

Fujii et al. [13] studied morphological structures of the cross section of various hollow fibers and fiat sheet membranes by high-resolution field emission scanning electron microscopy. Figure 6.8 shows a cross-sectional structure of a flat sheet cellulose acetate RO membrane. The layer near the top surface is composed of a densely packed monolayer of polymeric spheres, which is supported by a layer formed with completely packed spheres. The contours of the spheres in the top layer can be observed. The middle layer is also composed of loosely packed and partly fused spheres, which are larger than the spheres in the surface layer. In the middle layer, there are many microvoids, the sizes of which are the same as the spheres. The layer near the bottom is denser than the middle layer, and the spheres are deformed and fused. Interstitial void spaces between the spheres, which may be called microvoids, are clearly observed. This structure seems common for the flat sheet as well as the hollow fiber membranes. For example. Fig. 6.9 shows a cross section of a hollow fiber made of PMMA B-2 (a copolymer containing methyl methacrylate and a small amount of sulfonate groups). The inside surface layer is composed of the dense structure of compactly packed fine polymeric particles. The particle structure of the middle layer... 

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