Oxyethylene oligomers

New Phase Transfer Catalysts Containing Oxyethylene Oligomers... 

We would now like to report results on the synthesis of new vinyl derivatives of oxyethylene oligomers which readily undergo polymerization to give soluble or insoluble materials, depending on reaction conditions. Most importantly, these polymers are prepared in high yield from inexpensive starting materials and possess good phase transfer catalytic activity. 

The results of spectroscopic studies were reported for chain molecules such as n-alkanes or poly(oxyethylene) oligomers hosted in conventional nematic LCs. 

Gere Oxyethylene oligomers (non-ionic surfactant) Packed column polystyrene COa-methanol UV Eluent program... 

DAO Daoust, H., Darveau, R., and Laberge, F., Microcalorimetric irrvestigation on irrteraction between poly(acryUc acid) and oxyethylene oligomers in water. Polymer, 31, 1946, 1990. 

For instance, the synthesis of segmented poly(ether ester amide) copolymers with an aromatic polyamide block was attempted in N,N-dimethylacetamide solution, using a dihydroxy-terminated poly(oxyethylene) oligomer, >phenyl-enediamine, and isophthaloyl chloride [30]. Unfortunately, only low viscosity materials were obtained, probably due to side reactions involving the amide solvent (transamidation and acylation). 

Saito, Y., T. Sato, I. Anazawa, Poly(oxyethylene) oligomer distribution in a nonionic surfactant by means of TLC, Bull. Chem. Soc. Jpn., 1989,62, 3709-3710. 

Okada, T. (1990). Chromatographic oligomer separation of poly(oxyethylenes) on potassium ion-form cation-exchange resin. Anal. Chem. 62(4), 327-331. 

Ethynyl End-Capped Polyimide Oligomers Containing Oxyethylene Linkages... 

Fig. M2. Dependence of retention factors, k. on the number of oxyethylene units, n. in the individual ethoxylaied nonylphenol non-ionic. surfactants oligomers on a Sila,sorb SPH Cm (7.. ) pm) column (300 x 4.0 mm i.d.) in mobile phases containing 60 (/). 50 (2). 45 (.3). 40 (4) and 35 (5) 9r 2-propanoI in water. Points experimental data lines best-fit plots of Eq. (1.19) with the quadratic term equal to 0.

Polymers of this type have been prepared with various mesogenic units connected by oligomers of poly(ethylene oxide), PEO, and it is possible in some cases to use spacers having a broad distribution of molecular weights instead of a monodisperse molecular species. It shoxxld be noted that each oxyethylene unit adds three bond lengths to the spacer, so the comparison of polymers with different types of spacers should be between spacers having the same numbers of atoms in the spacer chain. 

The case for double layer formation in PEO-type oligomers has been made in a series of monodisperse a-methyl-c -hydroxy[oligo(oxyethylenes)], or C1E/)OH, where p is the number of oxyethylene units.47 The authors have applied the dynamic model by Minoni and Zerbi44 to describe the two strongest LAM peaks observed in Raman spectra. These correspond to what can be described as first and second modes of a dimer (see Figure 22). 

Monodisperse diblock oligo (ethylene oxide) mono-n-alkyl ethers have also been prepared and studied.143 Oligomers with hydroxy-ended E-blocks formed bilayer crystals (cf. Section II.G and Figure 22), and the methoxy-ended oligomers formed monolayer crystals. The helical oxyethylene blocks were perpendicular to the layer plane, while the alkyl blocks were generally tilted at 30° to the layer normal. Monodisperse triblock oligomers with a central methylene block and outer oxyethylene blocks were also studied subsequently144 and both fully crystalline and partly crystalline structures were found, with chains in wholly trans-planar and mixed trans-planar/helical conformations. 

MALDI-TOF analysis also revealed that transesterification reactions between propylene carbonate and diols containing six or more carbon atoms in the molecule, carried out in esence of a coordination catalyst, lead to almost pure oligocarbonate diols. When ethylene carbonate (EtC) was used, the resultant polymer contained a different combinahon of ethylene carbonate and ethylene oxide units. The transesterification with EtC, carried out in the presence of catalysts, such as K2CO3 and CsF, leads to oligomers with high amoxmts of oxyethylene fragmenfs. ... 

The melting and crystallization rates of oligomers and polymers were first measured by microscopy in the presence of remaining crystal, to eliminate nucleation effects. Figure 3.94 illustrates data for poly (oxyethylene) as a function of molar mass. On extrapolation to monomer dimensions, the metastabdity gap disappears and one... 

Lee et al. prepared the dendrimer-like oxyethylene-substituted bispyridine derivative 11 (Fig. 4.5b(i)) that formed coordination polymers or oligomers by Ag+ complexation, such as dispersed helical structures and discrete cyclic conformations [21]. 

In addition, ADMET has been utilized to polymerize a telechelic oligomer formed from the hydrosilation of 1,4-pentadiene with 1,1,3,3-tetramethyl-disiloxane [107]. ADMET has also been used to produce copolymers with backbone siloxanes and methoxy-substituted silanes [109]. These methoxy-substituted silanes gradually cross-link upon exposure to air, a potentially useful phenomenon (Figure 13.15). Carbosiloxane and oligo(oxyethylene) polymers... 

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