Monomers Eutectic

Only a few commercial uses for TDA per se have been found. In epoxy curing appHcations, 2,4- I DA has been used as a component of a eutectic mixture with short chain aUphatic glycidal ether resins (46) as well as by itself (46,47) TDA (46) and single isomers (47) are also used as amine curatives. TDA can be used as a chain extender in polyurethanes (48,49). TDA is cited as a monomer in making aromatic polymers with unique properties, eg, amorphous polyamides (50), powdered polyamides (51), and low melting, whoUy aromatic polyamides (52). 

R A. Monnard et al. from the laboratory of D. W. Deamer also worked on ice/eutectic phases at 255 K. They studied the influence of solutions of inorganic ions (such as Na+, CD, Mg2+, Ca2+ and Fe2+) both on the formation of vesicles and on non-enzymatic polymerization of activated RNA monomers (Monnard et al., 2002). 

In the case of non—eutectic systems, the solid phase shows nearly ideal mixing, so that the surfactant components distribute themselves between the micelle and the solid in about the same relative proportions (i.e., both the mixed micelle and mixed solid are approximately ideal). However, in the case of the eutectic type system, the crystal is extremely non-ideal (almost a single component), while the micelle has nearly ideal mixing. As seen in earlier calculations for ideal systems, even though the total surfactant monomer concentration is intermediate between that of the pure components, the monomer concentration of an individual component decreases as its total proportion in solution decreases. As the proportion of surfactant A decreases in solution (proportion of surfactant B increases) from pure A, there is a lower monomer concentration of A. Therefore, it requires a lower temperature or a higher added electrolyte level to precipitate it. At some... 

Attempts have also been undertaken to improve the processability of PMR imide resins through molecular weight adjustments and exchange of the monomers employed. LARC 160 as an example here Jeffamine AP22, a eutectic blend of MDA type amines, was used as a polyamine instead of the crystalline MDA. This modification provided a quasi melt processable PMR resin (15). Other modifications were studied with the aim of improving the thermal oxidative stability by using hexafluoroisopropylidene dipthalic anhydride as a monomer (16). 

The nematic LC is the original eutectic mixture of 35% (weight %) 4 (m-octyl oxy)-4-cyanobiphenyl (80CB) and 65% 4/-(n-pentyl)-4-cyanobiphenyl (5CB). The sample is doped with perylene and 2% (mol %) of NIAC, which is acrylate monomer containing the easily reduced l,4 5,8-naphthalenediimide moiety (see Scheme 3). Finally, 0.5% (mol %) of benzoin methyl ether (BME) is added to photoinitiate polymerization of the NIAC. 

Figure 2, range A) Figure 3 represents the experimentally found dependence of the optical yield of dimerization (proved by n.m.r. and specific-rotation measurements) on the initial R) S) composition of the monomers in samples crystallized under conditions near the thermodynamic equilibrium as expected, the values approximate well to 100% in range A, while dropping quickly to 0% in the eutectic range. 

In the absence of kinetic effects in the dimerization step the yield of diastereo-meric dimers of Scheme 4 reflects directly the R,S) microcomposition (m n) of each parent crystal (Scheme 5) this ratio could be measured by n.m.r. of the dimer mixtures (Figure 4 h) and proved to be 61 39 in the case of the eutectic, but to approach 50 50 for the pure metastable phase. The metastable phase is therefore the one we need for absolute asymmetric synthesis however, due to its metastability, it is difficult to crystallize it in the form of a pure homochiral phase. Nevertheless, when large crystals were grown rapidly from the melt, there resulted phases at least partially enriched with one of the two enantiomorphous forms and which upon irradiation yielded net asymmetric syntheses. The optical yields of dimerization and polymerization ranged from 0—35%, while the recovered monomer was always racemic, in keeping with an asymmetric synthesis due only to the crystalline environment. 

Both lead (Pb ) and some lead minerals catalyze the formation of up to 10 mers starting from the 5 -phosphorimidazolide of adenosine (5 -ImpA). 21, 22) The oligomers are linked mainly by 2 , 5 -phosphodiester bonds. Uranyl ion (U02 ) is a more efficient catalyst of the reaction of the activated nucleotides of A, U, and C. (23) Chain lengths 16, 10, and 10 monomer units (mers), respectively are formed that are linked mainly by 2 5 -phosphodiester bonds. When the Pb reaction is performed in the eutectic phase of water at -18° C for... 

Materials studied are polyaniline, poly(3-octylthio-phene)(POT), and mixtures of poly(3-octylthiophene) (POT) and poly(ethylvinylacelate) (EVA). The synthesis of polyaniline was carried out by oxidation of aniline monomer using (NH4)2S20g in HCl (1 M) -I-HBF4 (1 M) or in the eutectic NH4F, 2.35 HF as... 

Copolymers melt at lower temperatures than do homopolymers from the individual monomers. By increasing the amount ofta comonomer, the melting point decreases down to a minimum (this could perhaps be compared to a eutectic) and then rises again. 

Li, J., Zhao, Y, Wang, N., and Guan, L. (2011]. Frontal polymerizations carried out in deep-eutectic mixtures providing both the monomers and the polymerization medium, Chem. Commun., 47, pp. 5328-5330. 

The initial synthesis of the SOCM monomer was attempted via the reaction of l-methacryloxy-2,3-propanediol with dibutyltin oxide followed by treatment with the cyclic carbonate 5. However, this process failed to provide any significant quantity of the chloromethyl-methacrylate-substituted intermediate. If this route had been successful, the final SOCM monomer would have been comprised solely of the spiro-fused five-membered rings (3a). Instead, the synthesis of SOCM as shown in Figure 3 yielded a mixture of the 5-5 and 5-6-membered ring systems (3a and 3b, respectively). Each of these different structural isomers is also further subdivided into a pair of syn and anti diastereomers as shown in Figure 6. The complex eutectic mixture which results is a liquid of low viscosity that is well suited for use as a diluent and wetting agent. 

In order to widen the nematic range of the monomers and to decrease their melting temperatures, we have made binary mixtures of compounds n = 0 and n = 1 (Table l). We observed that the experimental diagram did not exhibit an eutectic, as is generally observed with other liquid crystals. The two compounds are probably miscible in all proportions in their crystalline state (solid solution). The phase diagrams, experimental and calculated, are plotted on Figure 1. 

The racemate of the monomer was found to be iso-stractural with its enan-tiomorph, as it crystallizes in the same space group as a sohd solution, where the sec-butyl groups of opposite handedness are disordered. However, an accurate determination of the phase diagram between S(+)l and R(—)1, under equilibrium conditions, revealed the presence of an immiscibiUty gap in the range 60 40 to 40 60 [49]. Therefore, the crystallization of a large batch of racemic 1 under thermodynamically controlled conditions was associated with the precipitation of equal amounts of crystals of either handedness, with a constant internal composition, as defined by the boundaries of the eutectic. The presence of an immiscibihty gap imphes two different effects on the one hand it interferes with the requirements of an absolute asymmetric synthesis from racemic 1, while on the other hand it provides a most efficient way in which to amplify chirahty via the crystalhzation of nonracemic mixtures of compositions, which are outside the boundaries of the eutectic. Enantiopure oHgomers could be generated from mixtures of molecular composition R S of 60 40 [50]. 

Poly(benzimidazoles) have high thermal stability, and there has been no lack of effort to increase the thermal stability even more through suitable choice of the initial monomers. If the dicarboxylic acids are replaced by tetracarboxylic acids or their anhydrides, and these are then converted with tetramines, then more or less perfect ladder polymers are formed. These ladder polymers all have a thermal stability about 100 K higher than PBI, and so can be used up to about 600° C. Poly(imidazopyrrolone) or pyrron, polypyrrolone, and poly(benzimidazobenzophenanthroline) or BBB may be specially mentioned in this respect. The synthesis of these difficultly soluble polymers must be mostly carried out in solvents such as polyphosphoric acid, zinc chloride, or eutectic mixtures of aluminum chloride and sodium chloride ... 

Commercial bismaleimide thermoset resins are based on aromatic bismaleimides such as 4,4 -bismaleimidodiphenylmethane (Compimid MDAB, Evraiik). Compimid MDAB, also known in literature as MDA-BMT is derived from the condensation reaction between 4,4 -methylene dianiline (MDA) and maleic anhydride, both relatively low-cost monomers. The MDA-BMI is often used as a eutectic mixture with other BMIs such as TDA-BMI, to reduce its melting point for improved impregnation and tackiness in the glass and carbon-fiber-based composite prepregs. 

Wunderlich et al. have also reported the preparation and sepeiration of extended chain crystals of polyethylene from the melt at 510 K and 500 MN m" and separating them by etching with fuming nitric acid. The product was, of course, an a,(o-dicarboxylic acid with a molecular length of about 900 —CH — units. Cavello et have grown crystals of random isotactic copolymers of propylene and but-l-ene from isoamyl acetate solution. By comparison with melt-crystallized materials they concluded that both morphologies, and hence crystallizations, were fundamentally identical, and that the co-monomer unit co-crystallizes. There is a depression of the melting point over that of the homopolymer and a eutectic is observed at 48% butene content. 

Bowen [148] obtained crystalline acrylic monomers, thus making it possible to purify them. By the reaction of 2-hydroxyethyl methacrylate with the three isomers of benzene dicarboxylic acid—phthalic, isophthalic, and terephthalic acid—adequate esters are obtained mixed in various proportions, these make an eutectic ternary mixture that can play the role of the organic phase in DARs. The only shortcoming of these monomers is that they show a tendency to acquire color in the presence of the polymerization accelerators (N,N-dimethyl-p-toluidine). Isomer dimethacrylates (o-, m-, and p-)bis(hydroxyethyl)-dihydroxybenzen-... 

Very little attention has been given to the production and evaluation of acrylic or methacrylic acid-MA copolymers. Some studies have shown that the acrylic acid-MA pair can be copolymerized to a 1 1 alternating copolymer, under the condition where MA concentration exceeds the acrylic or methacrylic acid concentration in the starting mixtures (see Chapter 10). Radiation-initiated, solid-state copolymerization of eutectic mixtures of acrylic acid with MA have been investigated by examination of phase diagrams, viscosities, and surface tensions of the binary mixtures.Molecular interactions between the two monomers and crystal dislocations accelerate the polymerization rate. The physical and chemical properties of the copolymers have not been explored. 

Esters of endomethylene tetrahydrophthalic anhydride and other derivatives of norbornene are known to form eutectic mixtures with Ma/ 2.73.340,341,374-379) SQij j.gtate copolymerizatiou of the eutectic mixture of monopropyl endomethylene tetrahydrophthalate and MA, using Co y-ray initiation, produces nonequimolar copolymer. " Neither monomer homopolymerizes under the experimental conditions used. It is believed that copolymerization of the monomer mixture is made possible by the increased... 

The copolymerization of acenaphthylene with MA has been studied, by several groups, under a variety of conditions.The two compounds form a eutectic mixture composed of 2 moles of MA and 1 mole of acenaphthalene, and has a melting point of 35.5-36°C. Pure alternating copolymers are best obtained by heating 80 20 (MA acenaphthylene) molar mixtures of the monomer pair with AIBN or BPO in dioxane. Solid-phase copolymerization with y rays, using a 1 000-Ci °Co source, produces both... 

Maleic anhydride grafting (cont.) poly(styrene-co-divinylbenzene), 694 poly(styrene-co-isobutylene), 675, 689 poly(styrene-co-nfialeic anhydride), 676, 679 poly(vinyl acetate), 676, 694 poly(vinyl acetate-co-vinyl fluoride), 678 poly(vinyl alkyl ethers), 675, 679, 692, 701 poly(vinyl chloride), 683, 692, 693, 695, 702 poly(vinylidene chloride), 691 poly(vinyl toluene-co-butadiene), 689 radical—initiated, 459-462, 464-466, 471, 475, 476 radiation—initiated, 459, 461, 466, 471, 474 redox-initiated, 476 rubber, 678, 686, 687, 691, 694 to saturated polymers, 459-466, 475, 476 solvents used 460-463, 465, 466, 469, 474-476 styrene block copolymers, 679 tall oil pitch, 678, 697 terpene polymers, 679, 700 thermally-initiated, 462, 464-467, 469, 476 to unsaturated polymers, 459, 466-474 vapor-phase techniques, 464, 474, 475 to wool fibers, 476 Maleic anhydride monomer acceptor for complex formation, 207-210 acetal copolymerization, 316 acetone CTC thermodynamic constants, 211 acetone photo-adduct pyrolysis, 195, 196 acetylacetone reaction, 235 acetylenic photochemical reactions, 193-196 acrylamide eutectic mixtures, 285 acylation of aromatic acids, 97 acylation of aromatics, 91, 92 acylation of fused aromatics, 92, 95, 97, 98 acylation of olefins, 99 acylation of phenols, 94-96 acylic diene Diels-Alder reactions, 104-111, 139 addition polymer condensations, 503-505 adduct with 2-cyclohexylimino-cyclopentanedi-thiocarboxylic acid, 51 adducts for epoxy resins curing, 507-510 adduct with 2-iminocyclopentanedithiocarboxylic acid, 51... 

The physical properties of the copolymers vary with melt point. The copolymers are more flexible as the composition approaches the eutectic point. Indeed, copolymers around the 50/ SO mole ratio of terephthalic/sebacic acid are elastomeric in nature, and were extensively studied by DuPont as elastic fibers. Eutectics are also observed in ethylene terephthalate/adi-pate and butylene terephthalate/sebacate copolymers. Introduction of an additional monomer, for example, sebacic acid or azelaic acid in butylene terephthalate/iosphthalate polymers, results in further modification of the properties. In general, introduction of the aliphatic chains results in lowering of the melting point, increased flexibility, greater adhesion properties, and in the case of crystalline polyesters, a faster ciystallization rate. 

Wittmaim JC, John Manley RS. Polymer-monomer binary mixtures. I. Eutectic and epitaxial crystallization in poly (e-caprolactone)-trioxane mixtures. J Polym Sci B 1977 15 1089-1100. 

Nwabunma D, Kyu T (2(X)1) Phase behavior, photopolymerization and morphology development in mixtures of eutectic nematic liquid crystal and photocurable monomer. Polymer 42 801-806 Ohta S, hiasawa S, Yamaguchi Y (2012) Size control of phase-separated liquid crystal droplets in a polymer matrix based on the phase diagram. J Polym Sci Part B Polym Phys 50 863-869 Parab SS, Malik MK, Deshmukh RR (2012) Dielectric relaxation and electro-optical switching behavior of nematic liquid crystal dispersed in poly (methyl methacrylate). J NonCryst Solids 358 2713-2722... 

EUTECTIC MONOMER SYSTEMS Aromatic Diester Dimethacrylates... 

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