Diepoxide molecule

A quantitative estimation of the fraction of the 1,1 -cycles can be performed through a conformational analysis of the diepoxide molecules, i.e. determination of the number of their conformations in which the end-to-end distance is equal to the spacing between the nitrogen atoms in the corresponding diamine molecules. Such an analysis has given results qualitatively constistent with those obtained in the analysis of the molecular models by the Stewart-Brigleb method U0, n1,, I4>. 

Network formation was generated on the lattice (hexagonal, tetragonal and cubic) with the total number of crosslinks amounting to 2-4 x 102. Tetrafunctional amine molecules were fixed in the lattice knots. This lattice was immersed in uniform liquid of diepoxide molecules which could penetrate the lattice freely. The network appeared as a result of an addition reaction between diepoxides and amine groups of crosslinks. 

These materials differ from the previous class of resin in that the basic structure of these molecules consists of long chains whereas the cyclic aliphatics contain ring structures. Three subgroups may be distinguished, epoxidised diene polymers, epoxidised oils, and polyglycol diepoxides. 

Bifunctional molecules such as diepoxides, diisocyanates, dianhydrides or bis(oxazoline)s have been shown to increase the molecular weight of PET [1,2] by reacting with its terminal groups. Triphenyl phosphite [3, 4], as well as diimidodiepoxides [5], have also proved to react efficiently with PET while promoting molecular weight enhancement. 

Effects of Curing Agent Type. Epoxide-Cured Propellant. Carboxyl-terminated polybutadiene is a linear, difunctional molecule that requires the use of a polyfunctional crosslinker to achieve a gel. The crosslinkers used in most epoxide-cured propellants are summarized in Table IV and consist of Epon X-801, ERLA-0510, or Epotuf. DER-332, a high-purity diepoxide that exhibits a minimum of side reactions in the presence of the ammonium perchlorate oxidizer, can be used to provide chain extension for further modification of the mechanical properties. A typical study to adjust and optimize the crosslinker level and compensate for side reactions and achieve the best balance of uniaxial tensile properties for a CTPB propellant is shown in Table V. These results are characteristic of epoxide-cured propellants at this solids level and show the effects of curing agent type and plasticizer level on the mechanical properties of propellants. 

Several methods of condensation were used and each of them consisted of binding the perfluorinated chain to a molecule which exhibited two hydroxy groups or a forerunner of the diol (e.g. epoxide-alcohol or diepoxide). 

Diepoxides from Diels-Alder addition products of quinone with two molecules of butadiene, which exist as several isomers (f.p., 179°, 186°, 216°, 260°, and 320°C. 

Chiral polymers have been applied in many areas of research, including chiral separation of organic molecules, asymmetric induction in organic synthesis, and wave guiding in non-linear optics [ 146,147]. Two distinct classes of polymers represent these optically active materials those with induced chirality based on the catalyst and polymerization mechanism and those produced from chiral monomers. Achiral monomers like propylene have been polymerized stereoselectively using chiral initiators or catalysts yielding isotactic, helical polymers [148-150]. On the other hand, polymerization of chiral monomers such as diepoxides, dimethacrylates, diisocyanides, and vinyl ethers yields chiral polymers by incorporation of chirality into the main chain of the polymer or as a pedant side group [151-155]. A number of chiral metathesis catalysts have been made, and they have proven useful in asymmetric ROM as well as in stereospecific polymerization of norbornene and norbornadiene [ 156-159]. This section of the review will focus on the ADMET polymerization of chiral monomers as a method of chiral polymer synthesis. 

A thermosetting appliance enamel consists of a terpolymer comprising about 72 parts of vinyl toluene (70/40 meta/para) with about 20 parts of ethyl acrylate (to reduce brittleness of the copolymer) and 8 parts of an acidic vinyl comonomer. The acid is incorporated in the copolymer to provide sites for subsequent cross-linking with a diepoxide. It seems reasonable to expect that grease and slain resistance of the cross-linked enamel will be enhanced if the cross-links are not clustered and almost all initial polymer molecules contain at least one or a few cross-linking sites. To achieve this in a batch copolymerization, what are the best reactivity ratios (approximately) of the major component (vinyl toluene) and the vinyl acid comonomer Show you reasoning. 

Among other molecules in this class are symmetrically substituted cyclic trans olefins of the type depicted in Fig. 10. All conformations of these molecules are asymmetric the reason, as in the examples already discussed, is that the plane of the trans olefin unit remains at all times perpendicular to the average plane of the — (CH2) CHR(CH2) — fragment. Given a sufficiently large ring size (n> 3), internal rotation about the single bonds of the olefinic moiety interconverts all conformational enantiomers. An example of this type is the meso diepoxide derived from trans, trans, transA,5,9-cyclododecatriene. ... 

Like all polymers, epoxy resins contain a mixture of molecular species. Not all molecules are terminated at both ends by epoxide groups. Low molecular weight diluents, containing perhaps one epoxy ring, are often included to make the diepoxide 0 types less viscous. Resins containing these diluents are described as modified epoxies. The solvents for epoxy resins are given in Tables 9.1 and 9.3. It should be noted that the petroleum hydrocarbons are non-solvents. 

Nishikubo, T, Kaineyama, A. and Minegishi, S. (1994). V novel synthesis of Poly(phosphonate) by the addition reaction of diepoxide with phenvlphosphonic dichloride. Macro molecules, 27, 2641-2642. 

The concept of an ultimate conversion lower than 100% is reasonable in view of steric restrictions in a highly crosslinked network. Oleinik has reported an ultimate conversion of 92% in a diepoxide-diamine stem. This ultimate conversion value is attributed to topological limitations and is consistent with computer simulations Hale reports an experimental ultimate conversion of less than 85% for a 1 1 stoichiometry ECN-phenolic cresol novolac (PCN) system which is similar to the one in this study. The lower ultimate conversion seen in the ECN-PCN stem is in agreement with greater steric hindrances arising from the cresol pendant group. The topological constraints on the ultimate conversion will increase as functionahty of the reactive molecules also increases. 

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