Butadiene lecithin

Influence of subphase temperature, pH, and molecular structure of the lipids on their phase behavior can easily be studied by means of this method. The effect of chain length and structure of polymerizable and natural lecithins is illustrated in Figure 5. At 30°C distearoyllecithin is still fully in the condensed state (33), whereas butadiene lecithin (4), which carries the same numEer of C-atoms per alkyl chain, is already completely in the expanded state (34). Although diacetylene lecithin (6) bears 26 C-atoms per chain, it forms both an expanded and a condensed phase at 30°C. The reason for these marked differences is the disturbance of the packing of the hydrophobic side chains by the double and triple bonds of the polymerizable lipids. At 2°C, however, all three lecithins are in the condensed state. Chapman (27) reports about the surface pressure area isotherms of two homologs of (6) containing 23 and 25 C-atoms per chain. These compounds exhibit expanded phases even at subphase temperatures as low as 7°C. 

In contrast to the topochemically polymerizable diacetylenes, methacryloylic and butadienic lipids are also polymerizable in the liquid like phase. Figure 11 shows the contraction behavior of butadiene lecithin (19) during irradiation in the liquid analogous state 22). The final polymer has a 1,4-trans structure22). 

The polymer is expected to be at least occasionally cross-linked Since the polymer chains are very flexible, the amphiphilic polybutadienes represent a better approach to biological membranes than the corresponding polydiacetylenes In particular of interest are partially polymerized membranes, which consist of polymerizable butadiene lecithines and saturated lecithines (e.g. dimyristoyl-lecithin, DMPC). While vesicles of DMPC exhibit a typical ripple structure, the surface of the polymerized vesicles appears homogeneous. Electron micrographs of mixed vesicles show a phase separation, indicated by the simultaneous presence of regions with a smooth surface due to the polymer, and rippled regions due to DMPC Instead of... 

Fig.11 Release of enclosed 6-carboxyfluorescein vs. concentration of added SDS for the butadiene lecithin (11)...

Chewmggum -in drug delivery [CONTROLLED RELEASE TECHNOLOGY - PHARMACEUTICAL] (Vol7) -flavor enhancer for [SWEETENERS] (Vol 23) -lecithin m [LECITHIN] (Vol 15) -SBRuse [STYRENE-BUTADIENE RUBBER] (Vol 22) -sugar alcohols m [SUGAR ALCOHOLS] (Vol 23)... 

Water-dispersible lecithins are made by chemical modification, or by mixing ordinary lecithin with nonionic surfactants. Many of the products recommended in the literature and technical brochures for water-based compositions include such chemically modified, water-dispersible, lecithin compounds (e.g., hydroxy-lated, acylated, fractionated, and refined grades) (428, 431 33). Usually 0.5% to 1% modified lecithin is recommended in polyvinyl acetate-based paints, acrylic emulsions, and in butadiene—styrene emulsion paints. 

Blendex HPP 820, Blendex HPP 821] Blendex HPP822] Blendex HPP823. See Polyphenylene ether Blendex MPE1000. See Acrylonitrile/butadiene/styrene copolymer Blendmax 322] Blendmax 322D] Blendmax K. See Lecithin... 

Thermolec WFC. See Hydroxylated lecithin Thermolin 101. See Tetrakis (2-chloroethyl) ethylene diphosphate S-B-S thermoplastic elastomer. See Styrene/butadiene/styrene block copolymer Thermoplastic polyurethane elastomer. See Polyurethane elastomer, thermoplastic Thermoset 100] Thermoset 104] Thermoset 206] Thermoset 210] Thermoset 211] Thermoset 261] Thermoset 264] Thermoset 265] Thermoset 267] Thermoset 270] Thermoset 281] Thermoset 285] Thermoset 286] Thermoset 300/No. 18 Hardener, Thermoset 300/No. 65 Hardener, Thermoset 300/No. 67 Hardener, Thermoset 300/No. 70 Hardener, Thermoset 302/No. 18 Hardener, Thermoset 305] Thermoset 310] Thermoset 312] Thermoset 313] Thermoset 316] Thermoset 317] Thermoset 321] Thermoset 323] Thermoset 326] Thermoset 329] Thermoset 350] Thermoset DC-23] Thermoset DC-88]... 

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