Head-group Characterization

H1 NMR spectroscopy was found to be unsuitable for head-group analysis of HSi-PaM-eSt. The resonance associated with the Si-H proton at the head-group is broadened by multiple splitting and the resonances of the aromatic protons of the initiator fragment are buried in the aromatic proton resonances of phenyl rings of the aMeSt repeating units. 

Head-group characterization by quantitative IR spectroscopy indicated 1.0 0.1 Si-H bond per polymer. This key data is evidence for the correctness of the proposition that PaMeSt carrying a Si-H head-group can be obtained by the use of HSi(CH3)2CH2CH29 CH2Cl/Me3Al initiating system. 

Isobutylene Polymerization with Sir-H Containing Initiator Me3Al Initiating System 

This section concerns the synthesis of polyisobutylenes (PIB) bearing a Si-H head-group (HSi-PIB) by the use of Si-H containing functional initiator in conjunction with Me3Al coinitiator. First the effect of reaction conditions on the rate and molecular weight have been investigated and subsequently a H1 NMR method for the quantitative characterization of Si-H groups in HSi-PIB was developed. 

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Further addition of fatty acid eventually results in the formation of micelles. Micelles formed from an amphipathic lipid in water position the hydrophobic tails in the center of the lipid aggregation with the polar head groups facing outward. Amphipathic molecules that form micelles are characterized by a unique critical micelle concentration, or CMC. Below the CMC, individual lipid molecules predominate. Nearly all the lipid added above the CMC, however, spontaneously forms micelles. Micelles are the preferred form of aggregation in water for detergents and soaps. Some typical CMC values are listed in Figure 9.3. 

Carbocationic Synthesis and Characterization of Polyolefins with Si-H and Si-Cl Head Groups 3... 

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