Copoly condensation

Copoly condensation of Functional Silanes and Siloxanes in Solution Using tris(pentafluorophenyl)borane as a Catalyst in a View to Generate Hybrid Silicones... 

To increase the basic physical-mechanical characteristics and repro-cessibility (the solubility, in particular), the polyesterketones and polyesteresterketones are synthesized [319-329] through the stage of formation of oligomers with end functional groups accompanied with the consequent production of block-copolyesterketones or by means of one-go-copoly-condensation of initial monomers with production of copolyesteiketones. 

When the copoly condensation is carried out in the melt, very often phase segregation takes place between the oligomer and the precursors of the other block, which may result in quite heterogeneous copolymers. This difficulty can be overcome in different ways. Caymans et al. [16] carried out a pre-polycondensation in a solvent (pyrrolidone) which resulted in a homogeneous mixture of... 

The incorporation of fluorine atoms improves the solubility of aromatic condensation polymers without causing them to lose their high thermal stability and modifies the processability. Hexafluoroisopropylidene-unit-containing poly-(azomethine)s and copoly(azomethine)s are readily soluble in highly polar solvents such as DMAc, HMPA, and NMP, and they also dissolve completely in dichloromethane, chloroform, and THF, whereas poly(azomethine)s derived from 21 and 22 and having no fluorine atom are insoluble in these solvents.20 Accordingly, the solubility of aromatic poly(azomethine)s is remarkably improved by substituting isopropylidene units with fluorine atoms. 

Introduced by Blout et a , for use in peptide synthesis, the reagent is prepared as shown in Chart I by condensing copoly(ethylenemaleic anhydride) (I, Monsanto DX840) with hydroxylamine hydrochloride in DMF. BOC-a-amino derivatives of alanine, phenylalanine, threonine, methionine, leucine, etc., were synthesized in... 

A series of lyotropic poly(imide-amide)s were synthesised [39], in which an ordered unit comprising trimellitimide condensed with p-aminobenzoic acid andp-phenylene diamine (PPD) was copolymerised in varying ratios (0,50 and 80%) with a terephthalic acid/PPD polyamide. The MI predicts all three polymers to be LC, but lyotropic behaviour was observed in only the first one (Table 13). This is particularly surprising because incorporating increasing quantities of the known lyotropic and more linear TPA/PPD units would be expected to produce definite lyotropic behaviour. Similarly, a copoly(amide-imi-de) of 3,3 -dimethyl benzidene and 4-amino benzoic trimellitimide was predicted by the MI to possess a mesophase but none was detected. These apparent failures may be due to the fact that the polymers which did show lyotropic behav-... 

Synthesis, structure, and properties of a set of alternating copoly(ester amide)s made from L-tartaric acid, succinic acid, and n-amino-l-alkanols (n=2, 3, and 6) (Figure 8.14) have been studied in order to understand the influence of the heterogeneity introduced in the polymer microstructure from the differences in constitution of succinic and tartaric units [59,60]. These PEAs contained equal amounts of amide and ester groups and were stereoiegular and easily synthesized by the condensation of the p-toluene sulfonate salts of bis(aminoaIkyl) succinates with active esters of tartaric acid. Polymers displayed... 

Random copoly(p-phenylene sulfide sulfone/ketone)s were easily prepared in high yield ( 95-99%) by the solution (NMP) condensation of sodium hydrosulfide (NaSH) with bis(4-chlorophenyl) sulfone (4,4 -dichlorodiphenyl sulfone) [80-07-9] and 4,4 -dichlorobenzophenone [98-98-2]. Copolymers with sulfone/ketone molar ratios > 25 75 were amorphous, whereas those with ratios < 25 75 were crystalline. These materials form tough, creaseable films and exhibit a linear increase in the Tg from 144 to 215°C, with increasing sulfone content (62). 

Vallance, M.A. and S.L. Cooper, Microstructure in linear condensation block copolymers A modeling approach. Macromolecules, 17(6) p. 1208.1984. Gabrielse, W., M. Soliman, and K. Dijkstra, Microstructure and Phase Behavior of Block Copoly(ether ester) Thermoplastic Elastomers. Macromolecules, 34(6) p. 1685. 2001. 

For example, it is reported in Ref. [186] on the synthesis of block-copoly-esters and their properties in dependence on the composition and structure of oligoesters. The oligoesters used were oligoformals on the basis of diane with the degree of condensation 10 and oligosulfones on the basis of phenolphtha-lein with the degree of condensation 10. The synthesis has been performed in conditions of acceptor-catalyst polycondensation. 

High Molecular Weight Copoly(3939595-tetrainethyl-4-oxa-395-disila-l,7-heptany-lene/2-aceto-l,3-phenyiene)(Copoly-XI). Ru catalyst (0.1 Ig, 0.12 mmol) and toluene (1 mL) were placed in a 50 mL three-neck round-bottomed flask equippped with a reflux condenser and a Teflon-covered magnetic stirring bar. The other two necks of the flask were sealed with rubber septa. Vinyltrimethoxysilane (0.16 mL, 0.018 g, 0.12 mmol) was added via a syringe. The flask and its contents were heated to 135 C for 1 min. At this time, a mixture of acetophenone (0.48 g, 4 mmol) and 1,3-divinyltetra-methyldisiloxane (0.74 g, 4 mmol) were added. The reaction was heated at 135 C for 12 h. After work-up, 0.9 g, 74% yield of copoly-XII, = 40,600/14,800 and T ... 

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