Poly di

Quaternary ammonium bromides and hydroxides (quats) are applied as templates in the synthesis of zeolites with relatively high Si/Al ratio. Examples will be given of the use of mon-, di-, poly- and associated quats as templates in zeolite growth. Templated zeolites of the MFI-type can be grown in a lateral or in an axial way onto metal supports, providing promising composite systems, for separation and catalysis, respectively. 

Most DNA, natural and synthetic, can adopt the B-form as defined by its characteristic X-ray pattern [3]. There are few a species of synthetic DNA, namely poly(dA) poly(dT), poly(dI) poly(dC), poly(dA-dI) poly(dC-dT) and poly(dI-dC)-poly(dI-dC), which have a B-form that significantly differs from that of the other complementary deoxy polymers due to their different intramolecular packing arrangements and slightly changed value for the rise per residue. The helix parameters are presented in Table 1. The linear sequen-... 

This book reviews some of the results of investigations of chemical conversions of chloral and TNT to new aromatic di(poly)amines and aromatic tetracarboxylic acid dianhydrides useful for the preparation of new polyimides combining good thermal, mechanical and electrical properties with improved processability. 

Di-poly Aldehydes (and ketones) FFAP QF-I, Porapak-Q, Porapak-QS Apiezon L, M carbowax 400, 750, 1000, 1500, 1540 di-n-butyl phthalate diethylene glycol succinate ethylene glycol succinate Hallcomid M18 squalene tricresyl phosphate 1,2,3-tris (2-cyanoethoxy) propane Ucon series... 

Complex compounds obtained by oxidative dissolution of elemental metals in the systems M°-ligand-solvent-HX (or halogen-substituted hydrocarbon), are represented by all types of complexes [509]. However, their ratio is not equal they are mainly molecular complexes and metal chelates the % -complexes and di(poly)-nuclear coordination compounds are not numerous. A large number of molecular (neutral and ionic) complexes, chelates, and their adducts, mostly with N-bases, are tabulated in monographs [201,202]. 

DTA curves of C-S-H(I) preparations show endotherms at I00-200 C and exotherms at 835-900°C, the latter temperatures increasing with Ca/Si ratio (KI7). C-S-H(di,poly) preparations gave somewhat similar results (S46), but the temperature of the exotherm varied erratically with Ca/Si ratio and, except at Ca/Si = 0.8, an additional endotherm occurred at 332-372°C. Solvents that dissolve lime, such as ethyl acetoacetate, have little action on preparations with Ca/Si ratios of 1.25-1.33, but remove CaO from ones of higher Ca/Si ratio until that composition is reached (K17,S46). 

From their studies on C-S-H(di,poly) , Stade and Wicker (S45) concluded that Ca and OH ions could both be present in the interlayer region of a tobermorite-like structure. Stade (S46) suggested that in the products containing both dimeric and polymeric ions, one surface of each tobermorite-type layer was composed of dimeric, and the other of polymeric, ions, thus accounting for the observed near-constancy of dimer/ polymer ratio. In the purely dimeric material isolated at — IO C. both surfaces were composed of dimeric ions. 

Standstrom [3] improved the elongation at break properties of tires by blending 70% di-poly(l,4-isoprene) with 30% poly(butadiene) containing a high trans content. The latter was prepared using barium di(ethylene glycol) ethyl ether, tri-octyl aluminum, and n-butyllithium as the reaction catalyst mixture. 

It has been suggested that carboxyl ester lipase has two different bile-salt-binding sites [34-36], one nonspecific for the bile salt structure and one specific for primary bile salts causing the di(poly)merization. An interesting question is whether the bile salts regulate substrate specificity not only by bile salt-enzyme interactions but also by forming the appropriate substrate surface structure [27]. 

The behavior of methine-labeled poIy(ethyl acrylate)-di (PEA-di), poly(wo-propyl acrylate)-di (PIPA-di), and poly(n-butyl aciylate)-di (PNBA-di) has been studied with deuterium NMR relaxation time measurements in concentrated solutions with chloroform. PEA-di and PNBA-di behaved similarly in terms of solution dynamics, but PIPA-di was found to reorient significantly faster at similar concentrations. The relaxation times were fitted to a log-normal distribution of correlation times and the resulting mean correlation times fit to Arrhenius behavior. The energies of activation were found to increase with increasing concentration from about 6 kJ/mol at lower concentrations to 10-20 kJ/mol from about 40 to 80 wt % polymer. 

In the above equation the R group designates the particular acrylate. Ethyl, iso-propyl, and / -butyl acrylates were produced yielding the polymers poly(ethyl acrylate)-di (PEA-di), poly(wo-propyl acrylate)-di (PIPA-di) and poly(n-butyl acrylate)-di. For PIPA the viscosity average molecular mass was measured to be 98,000 daltons.(5) The molecular masses of the other polymers were not estimated directly because their Mark-Houwink coefficients were not known, but they had similar intrinsic viscosities. At these molecular weights, we expect the relaxation times to be independent of molecular mass.(i)... 

The Ullmann reaction was used in the coupling of a wide variety of aryl halides, Ar-X, where the Ar includes mono-, di-, poly-substituted phenyl [4,5,14], naphthalene [4,5,15,16], azulene [17], pyridine [18], pyrimidine [19], thiophene [4,5,20], carbazole [21], and even ferrocene [22], while X = I, Br, Cl. The reaction was successfully used in the intramolecular cyclization reactions affording four- [23], five- [24], six-membered [25], and some other larger rings [6]. Selected examples where halides 10-13 were converted to biaryls 14-17 are given in the Scheme 2 [14,16,17,19]. 

Fig. 2 EE-SEM images of PCL and its indicated nanocomposites before and after soil burial (compost). The numbers after the specimen name represent the biodegradation time in days. 0 indicates the sample before biodegradation. Nanoparticles were ion-exchanged with di-methyl di-tallow ammonium (MAE), di-poly oxy ethylene alkyl methyl ammonium (MEE), and calcium phosphate hydroxide [hydroxyapatite (HA)] [29]...

A recent patent application disclosed a method for making polyurethanes made from nitrite esters and di/poly-isocyanates with the help of UV-irradiation for use as coatings. The application disclosed polymerizable and curable compositions and processes of polymerizing and curing polyurethanes involving an isocyante compound and a nitrite ester compound. Irradiation of the nitrite ester compound with UV generates an active hydrogen compound by the Barton nitrite photolysis reaction that reacts with an isocyanate compound to produce and/or crosslink a polyurethane. 

Figure 2. Structural diversity of the di(poly)nuclear structure. The bottom graph represents variations possible within the 1,1 series.

Sulfides s. a. S-Acoxy-sulfides, Di-, Poly-, Thioethers Sulfido compounds... 

The authors tested the effects of derivatives of 2,6-di-tert-butylphenol in which the sulphur is present in the form of mono-, di-, poly- and hydrosulphide groups as molecular mass regulators for emulsion butadiene-styrene rubbers. 2,6-di-tert-butyl-4-mercaptophenol is recommended as giving latices with good physical properties and polymers with fragments of chemically combined antioxidant. 6 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. RUSSIA... 

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