Modified oligomers

Chain Extendable Urethane Modified Epoxy Oligomer. The chain extendable urethane modified oligomers were prepared by combining equimolar amounts of epoxy-diol adduct and half-blocked diisocyanates, and heating the resulting mixture at 80°C for 4-6 hours until the isocyanate Infrared band disappeared. 

Enamel Properties. Clear coatings were formed by crosslinking the PHBA-modified oligomers with a standard melamine resin. Baking at 175° was necessary to obtain optimal properties. The cured films were glossy and nearly transparent except for films made from 60/40 PHBA ratio polyol. Adhesion was excellent. 

The m-hydroxybenzoic acid modified oligomers cured at 175° to give hard but brittle films. All failed the 80 in-lb impact resistance test. 

The modified oligomers mentioned above are nontoxic liquids, which boil above 200-300 °C at 1.3-4 GPa. Their viscosity ranges from 40 to 300... 

When the ruthenium-modified oligomer is annealed to its unmetal-lated complement, the metal complex intercalates and intense luminescence is observed (77). By contrast, the ruthenium-modified oligonucleotide alone or in the presence of noncomplementary single-stranded DNA displays little luminescence. These results are consistent with previous studies luminescence is observed in aqueous solution only when the stacked bases of a DNA helix provide a platform for intercalation of the dppz ligand. 

Relative viscosities of modified oligomers, determined by viscosimetry technique, are somewhat higher than the values of the respective initial oligomers (Table 5). The observed phenomenon allows to believe, that in the interaction of oligomers with phenols and element sulfur there occurs an increase in molecular weight due to the functionalised product generated. 

According to the element analysis results, the determination of modified oligomer relative viscosities, to the spectra data and references [7], the scheme of interaction of oligoisobutylene-alkylated phenols with element sulfur in our case can be written in the following way ... 

A versatile synthetic route to stereochemically pure 2 -deoxyguanosine-3 -phosphate adducts of cyclopenta[cf/lpyrene, applicable to other nucleosides, has been described to gain access to site-specifically modified oligomers as well as to access chromatographic standards to definitely identify stereochemical... 

Modified oligomer Stationary phase Eluent system Reference... 

The diastereoisomers of the modified oligomers were separated by reverse-jdiase hpic and their... 

Figure 3.12 Temperature dependences of the strength Up (1-4) and the deformations p (1-4 ) for polymers based on the initial oligomers (1, 1, 3, 3 ) and oligomers modified by SKD-KTRA rubber (2, 2, 4, 4 ). The ratio of the oligomer to the rubber in the modified oligomer is 80 20.

Selected examples have been cited to demonstrate that areas of acrylic, anaerobic and radiation-curable adhesive developments have begun to consider telechelic polybutadiene/acrylonitrile liquids as useful formulating ingredients either in direct admixture or in the preparation of rubber-modified oligomers serving as an adhesive formulating base. These cited adhesive examples cover structural, semi-structural, gap-filling and pressure-sensitive types. 

We have discussed modified nucleoside phosphoramidites (Section 2.1) and modified nucleoside triphosphates (Section 5.1) and their uses as the monomers for chemical or enzymatic synthesis of modified oligomers (oligonucleotides and oligodeojqmucleotides). In this section, our emphasis is primarily on interesting properties of modified oligomers. 

---