Monomers naphthalene

Shao, Jiping, and Rensselaer Polytechnic Institute Chemistry Dept. Linear Liquid Crystal Polymers from Phenylene-Naphthalene Monomers. New York Marcel Dekker, 2002. 

In eqns, (10) through (13) the superscript 1, 2, and 3 refer to the steady state and lifetime measurements respectively, while and T refer to the average lifetimes of the naphthalene monomer fluorescence defined in eqn. (6) and (7). The subscript 0 refers to the value in the absense of Cu. The fluorescence decay parameters are given in Table 3. The values of Kg and k are given in Table i( and the quenching curves are displayed in Fig. 3. 

The naphthalene monomer fluorescence lifetime is shortened by the solubilized Anth to an extent in reasonable agreement with the observed v values. Following the general analysis of Fredrickson and Frank , we have argued that x can be estimated from the fluorescence decay from the expression... 

An important structural modification which results in a parallel offset within the polymer backbone is the incorporation of 2,6-difunctionalized naphthalene monomers. 

DuPont workers have described (7) a wide variety of tractabilizing molecules and the thermotropic polyesters derived therefrom. Their research has focused for the most part on ring substituted monomers such as chloro, methyl or phenyl substituted hydroquinone and swivel" or linked ring molecules, examples of which are 3,4 or 4,4 functionally (hydroxy or carboxy) disubstituted diphenyl ether, sulfide or ketone monomers. Use of the parallel offset or crankshaft" geometry provided by 2,6 functionally disubstituted naphthalene monomers has been the major thrust of the Celanese Corporation development of easily processed, high performance wholly aromatic thermotropic polyesters. 

Scheme 12 Synthesis of poly(naphthalenecarboxamide) by chain-growth condensation polymerization of naphthalene monomer 17...

Since resonance effects can work between functional groups not only at the para position of benzene, but also at the 1,5- or 2,6-posiotion of naphthalene, we extended the range of monomers, leading to well-defined aromatic polyamides, from benzene monomer to naphthalene monomer (Scheme 12). 

Sodium naphthalene [25398-08-7J and other aromatic radical anions react with monomers such as styrene by reversible electron transfer to form the corresponding monomer radical anions. Although the equihbtium (eq. 10)... 

Aromatic radical anions, such as lithium naphthalene or sodium naphthalene, are efficient difunctional initiators (eqs. 6,7) (3,20,64). However, the necessity of using polar solvents for their formation and use limits their utility for diene polymerization, since the unique abiUty of lithium to provide high 1,4-polydiene microstmcture is lost in polar media (1,33,34,57,63,64). Consequentiy, a significant research challenge has been to discover a hydrocarbon-soluble dilithium initiator which would initiate the polymerization of styrene and diene monomers to form monomodal a, CO-dianionic polymers at rates which are faster or comparable to the rates of polymerization, ie, to form narrow molecular weight distribution polymers (61,65,66). 

Similar regiospecific syntheses employing PMBs and diaLkylnaphthalene have been used to prepare 2,6-dimethyl naphthalene [581-42-0] which is oxidized to the corresponding 2,6-naphthalenedicarboxyHc acid [1141-38-4] also used as a monomer for Hquid crystal polymers. 

Many different combinations of carboxyflc acid and hydroxyl groups have been tested to form LCPs. An aromatic stmcture (ben2ene, naphthalene, anthracene, etc) is required that has its functional groups symetricaHy arranged on opposite sides of the molecule. Examples are a 1,4-substituted ben2ene compound or 2,6-substituted naphthalene compound. These monomers are often complex and expensive molecules and account for a significant portion... 

Let us discuss now the conditions required for the electron transfer process. This reaction requires, of course, a suitable electron donor (a species characterized by a low ionization potential) and a proper electron acceptor, e.g., a monomer characterized by a high electron affinity. Furthermore, the nature of the solvent is often critical for such a reaction. The solvation energy of ions contributes substantially to the heat of reaction, hence the reaction might occur in a strong solvating solvent, but its course may be reversed in a poorly solvating medium. A good example of this behavior is provided by the reaction Na -f- naphthalene -> Na+ + naphthalene". This reaction proceeds rapidly in tetrahydrofuran or in dimethoxy... 

It must finally be kept in mind that it is extremely easy to adjust the properties of polyesters to desired values by adding small quantities (usually less than 10%) of comonomers in starting monomer feed. Isophthalic, adipic, dodecanedioic, p-hydroxybenzoic acids or esters and diethylene glycol, cyclohexanedimethanol, or bisphenol-A are often used for this purpose. Examples of property adjustment are the modification of solvent diffusivity of PET membranes by the addition of low levels of isophthalate or naphthalene dicarboxylate units in polymer chains139... 

DECOMPOSITION OF POLYETHYLENE 2,6-NAPHTHALENE DICARBOXYLATE TO CONSTITUENT MONOMERS USING SUPERCRITICAL METHANOL... 

Homopolymers and copolymers from amido-sulfonic acid or salt containing monomers can be prepared by reactive extrusion, preferably in a twin screw extruder [1660]. The process produces a solid polymer. Copolymers of acrylamide, N-vinyl-2-pyrrolidone, and sodium-2-acrylamido-2-methyl-propane sulfonate have been proposed to be active as fluid loss agents. Another component of the formulations is the sodium salt of naphthalene formaldehyde sulfonate [207]. The fluid loss additive is mixed with hydraulic cements in suitable amounts. 

The naphthalene radical-anion transfers an electron to a monomer such as styrene to form the styryl radical-anion which dimerizes to a dianion... 

Anionic polymerization of 1,4-DVB by n-BuLi leading to the microgels was also reported by Eschwey et al. [236,237]. In their experiments, n-BuLi was used at very high concentrations of 17 and 200 mol % of the monomer. Contrary to the results of Hiller and Funke [231], they observed a transition from microgel to macrogel with decreasing n-BuLi concentration. Similar results were also reported by Lutz and Rempp [238]. They used potassium naphthalene as the initiator of the 1,4-DVB polymerization and THF as the solvent. Soluble polymers could only be obtained above 33 mol % initiator, whereas below this value macrogels were obtained as by-products. 

Only a few publications have appeared in which for the synthesis of reactive microgels other monomers were used than 1,4-DVB or EDMA. Hiller and Funke studied the anionic polymerization of 1,4-diisopropenylbenzene (1,4-DIPB) by n-BuLi in 1,2-dimethoxyethane and by sodium naphthalene in THF [231]. 

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