Polyalkyl methacrylate

Conversely, vesicants have also been thickened with various substances to enhance deployment, increase their persistency, and increase the risk of percutaneous exposure. Thickeners include polyalkyl methacrylates (methyl, ethyl, butyl, isobutyl), poly(vinyl acetate), polystyrene, plexiglas, alloprene, polychlorinated isoprene, nitrocellulose, as well as bleached montan and lignite waxes. Military thickener K125 is a mixture of methyl, ethyl, and butyl polymethacrylates. When thickened, agents become sticky with a consistency similar to honey. Typically, not enough thickener is added to affect either the color or odor of the agent. 

The Tg decreases progressively as the size of the alkoxy group increases from methyl to decyl in polyalkyl methacrylates, but then increases. Explain. 

The presence of two substituents on every alternate carbon atom restricts chain mobility, so polyalkyl methacrylates are less flexible than the corresponding polyalkyl acrylates. Also, the presence of an alpha alkyl group increases (compared with the corresponding polyalkyl acrylates) the stability of polyalkyl methacrylates to light and chemical degradation,... 

Unlike the polyalkyl acrylates, which are thermally degraded by random chain scission, polyalkyl methacrylates unzip when heated, and excellent yields of the monomers are produced when the polymers of the lower homologues are heated. When higher homologues are heated, there is also some thermal degradation of the alkyl substituents. 

Pyri di ne-contai ning polyalkyl methacrylate Acryloid 917 (contains... 

Polyalkyl methacrylates decompose at temperatures accessible to rapid soldering techniques. 

Figure 2. Platelet retention by polyalkyl acrylates and by polyalkyl methacrylates plotted vs length of the alkyl side chain (A) or glass transition temperature, Tg (B). (Replotted from data in Fig. 3 of Ref. 17.)...

Thus, for the 4 polyalkyl methacrylates tested, the kinetics of fibrinogen adsorption differed for fibrinogen solution, whole plasma and diluted plasma. However for each one of these three media, fibrinogen adsorption to each of the four methacrylates did not differ significantly. The measured amounts of adsorbed fibrinogen did not, therefore, correlate with the platelet reactivity of the polymers, as previously assayed in polymer-coated bead columns. 

TABLE 2. Binding of Anti-fibrinogen Antibody (Fg-Ab) to Polyalkyl Methacrylate Polymers Previously Exposed to Fibrinogen ... 

Figure 6. Correlation of anti-fibrinogen antibody binding with platelet activation by polyalkyl methacrylates. Polymer-coated glass cover slips were exposed first to fibrinogen solution (250 ug/ml) and then to 1 25x-labeled antibody solution (300 ng/ml, 800 cpm/ng). (Reproduced with permission from Ref. 24. Copyright 1986 Grune Stratton.)...

SIMS can be effectively utilized to distinguish, for example, among a series of polyalkyl methacrylate films deposited on a metal substrate. 

Haldon, R. A., Simha, R., Multiple transitions in polyalkyl methacrylates. Journal of Applied Physics, 39(3), 1890-1899 (1968). 

Chem. Descrip. Polyalkyl methacrylate polymer in hydrocarbon oil Uses Vise, index improver for formulation of high vise, index hydraulie fluids emulsifier, dispersant for emulsion polymerization reaetive diluent for adhesives and eoatings... 

Chem. Descrip. Polymethyl methacrylate-based polymer Uses Binder for polyalkyl methacrylate plastisols used for chlorhydric-free coatings for underbody protection, coil coatings, base and top coat coatings, plastics coatings, PVC finishing heat-sealing raw material for pkg. of foods and pharmaceuticals... 

MULTIPLE TRANSITIONS IN POLYALKYL METHACRYLATES. HALDONRA SIMHA R J APPL PHYS... 

Anionic techniques are used to synthesize the polyalkyl methacrylate homo- and copolymers. Polymerizations are generally run in THF, toluene, or hexane at -78 C under inert atmosphere. The polymerizations involve formation of the hindered, less-basic initiator diphenyl hexyl lithium (DPHL) which is a product of the reaction of diphenyl ethylene (DPE) with s-butyl lithium. Then the purified methacrylate monomer of choice is very slowly... 

FIGURE 4,1 Compositional window of miscibility for blends of polyalkyl methacrylates with a styrene copolymer and hydroxyl group. 

Viscosity index Zinc dithiophosphate Polyalkyl methacrylate 10 25.5 21 16.5... 

H. Gisser (Frankford Arsenal) I would like to make a comment on the matter of side chains. in the case of teflon and hexafluoro-propylene, there is no question about the effect of trif 1uoromethyl group which increases the friction coefficient. When one studies polyalkyl methacrylate, one finds that the effect of side chain is different. Of course, the simplest one already contains a side chain, but when the length of side chain increases, for example, polyethyl methacrylate, polypropyl methacrylate, the friction coefficients decrease. It turns out that we are dealing with different materials. Polymethyl methacrylate is. an amorphous (random) material, but the higher methacrylates begin to show crystallinity. 

If this result is applied to PMMA we find that the difference in flex energies, Ae, between the syndiotactic and isotactic isomers of any polyalkyl methacrylate configurational pair is 191R or about 380 cals/mole, and, it is predicted the T difference for any member of the series should be 112°. Tflis is based on the assumption, it must be emphasized, that the configurational effect is an intramolecular effect. 

Other recent applications of ToF-SIMS without XPS include the examination of PS [6, 17-19], polyethylene (PE) [20], carbon fibre reinforced epoxy resins [21], polyalkyl methacrylates [22], alkylketene dimers [23], perfluorinated polymers [24], perflnorinated ethers [25], polyethylene glycol (PEG) oligomers [15, 25-29], rubber [30], ethylene-tetrafluoroethylene copolymer [30], Nylon-6 [31], PC [32,33], PDMS [34], polypyrrole coated PS [35], poly-p-phenylene vinylene [36], butyl rubber [37], poly(4-vinyl phenol)/poly(4-vinyl pyridine blends) [38], polypyrrole-silica gel composites [39], y-glycidoxypropyl trimethoxy silane [40], triblock copolymer poly(ethylene glycol)- 3 poly(phenylene ethylene)- 3 poly(ethylene glycol) [41], ethylene-terephthalate-hydroxybenzoate copolymer [42], PS-polyvinyl methyl ether, polycarbonate - PS blends [43] and PDMS-urethane [44],... 

Chem. Descrip. Sol n. of polyalkyl methacrylate in a highly refined mineral oil Uses Vise, index improver, pour pt. depressant for gasoline and diesel engine oils low-temp, soot dispersant... 

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