Oligomeric material

Higher a-olefins can also be polymerized with cationic initiators to fiquid oligomeric materials with isomerized stmctures. These fiquids are manufactured commercially and used as lubricating oils. 

While the chemistry of radiation curable hot melt adhesives is the same as that used in liquid (syrup) adhesives and coatings discussed elsewhere in this volume, there is a fundamental difference between the objectives of reaction in the two types of systems. Syrups consist largely or entirely of reactive monomeric and/or oligomeric materials. Radiation is used to initiate the polymerization of virtually the entire mass. In contrast, hot melts generally contain polymers initially, and these polymers are capable of reaction via radiation to produce chain extension and... 

The polymerization of 2-furaldehyde by sodium and sodium naphthalene reported by Kulakov and Kamenskii151 did not produce structure 32, but rather some resinous oligomeric materials formed through the interactions of the furan ring with the formyl group. 

Considerable low molecular weight, oligomeric material is usually produced along with high polymer, so that the yield of true polymer is often less than 50%. In a typical workup, a small amount... 

With an effective catalytic resolution of allylic styrene ethers in hand, we focused our attention on the Ru-catalyzed reaction of disubstituted styrenyl ethers (e.g., 49). When we treated (S)-49 with 10 mol% la under an atmosphere of Ar (Scheme 12), we found chromene formation to be sluggish 25-30% of dimer (S,S)-50 was isolated after 48 h at 45°C, together with substantial amounts of oligomeric materials. 

This polymerization16 proceeds quickly at ambient temperatures to give an oligomeric material (7) with Mw of 4000 to 6000 (Table 4.1). Compound 6 was also homopolymerized under similar conditions to afford an oligomer (8) with Mw 5000.+ These new oligomers were characterized by H- and 19F-NMR spectroscopy as well as elemental analysis. 

Figure 3. Effect of water on the reaction of hexafluorobenzene and bisphenol-A in chlorobenzene in the presence of 18 crown-6 catalyst. Products of the catalyzed reaction were oligomeric materials. No reaction is observed under the experimental conditions in the absence of the 18-crown--6 catalyst. (Reproduced with permission from reference 14, Copyright 1985 John Wiley.)...

A Waters Model 150C ALC/GPC was interfaced to a minicomputer system by means of a microcomputer for automated data collection and analysis. Programs were developed for conventional molecular weight distribution analysis of the data and for liquid chromatographic quantitative composition analysis of oligomeric materials. Capability has been provided to utilize non-standard detectors such as a continuous viscometer detector and spectroscopic detectors for compositional analysis. The automation of the instrument has resulted in greater manpower efficiency and improved record keeping. 

Attempts to prepare a bicyclobutane by reductive cydization of cyclobutane-1,3-diones have been unsuccessful [114]. a,o)-Dibenzoylalkanes are reduced at a mercury cathode to cycloalkanediols only when a ring size of 5 or 6 results. These reactions have been achieved using either aqueous ethanolic sodium hydroxide [115] or acetonitrile containing tetramethylammonium tetrafluoroborate [113] as electrolyte. Attempts to extend the process to formation of 7-membered rings lead only to oligomeric materials. 

Methylalumoxane (MAO) (structure 5.52) is the most widely utilized counterion. MAO is an oligomeric material with the following approximate structure ... 

Some of the tin stabilizers are based on oligomeric materials first made by Carraher and coworkers. These oligomeric materials are essentially nonmigrateable. ... 

Synthetic motor oils also contain oligomeric materials containing 12-20 carbons formed from alpha-olefins generally containing 5, 6, and 7 carbon-containing units as shown in the following equation for a Cs unit ... 

Vapor pressure osmometry is slightly less sensitive than membrane osmometry (M < 2 X 10 ) but is not affected by very short chains in the polymer sample which migrate through the semipermeable membrane in the case of membrane osmometry. Therefore, it is in particular valuable for the analysis of oligomeric materials. 

Observations Polymeric and oligomeric materials having good resistance to photo... 

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