| Summary: | 博士 === 國立臺灣科技大學 === 高分子系 === 94 === In this study, two series of cleavable surfactants were prepared and
the surface activities were investigated. A series was protein derivative
surfactant and the other was modified silicone surfactant. Surface active
protein derivative surfactants were formed by covalent attachment of
hydrophobic groups of alkenyl succinic acid anhydride to protein
molecules by alkali hydrolysis. The structure of the final products was
confirmed by IR, NMR and the average molecular weight was determined
by potentiometric titration and mass spectrometry. The surface activity
was evaluated by surface tension, contact angle, emulsifying power and
foaming properties. It was found that the modified proteins are more
surface active than the unmodified proteins. The increase in hydrophobic
chain length and the number of attached alkyl chains per protein molecule
leads to an increase in the surface activity. The modified protein
derivative surfactants also have high foaming ability and high
emulsifying ability, while the maximal surface activity is obtained by the
C12 modified protein. The biodegradability of these surfactants was also
studied, they possessed highly biodegradable properties. A series of
cleavable silicone surfactants was prepared by the reaction of a
hydroxyl-terminated polyester and an organopolysiloxane. The
experimental results indicated that the solution that contained the silanols
is the hydrophobic segment, however the polyoxyethylene chain
(nonionic) and sulfonate group (anionic) are hydrophilic, modified
siliocne surfactants exhibited excellent surface active properties and
softness.
The pH-dependent surface properties of a series of protein derivative
IV
surfactants, containing an oligopeptide residue and alkenyl groups, were
studied. The results showed that the surface activities of protein
derivatives and their detergent properties for T/W fabrics were improved
at low pH. These improved features make protein derivative surfactants
suitable for use as cleaning agents for lime-degradable substrates such as
hair and wool, and not hurt hair and wool structure. Cleavable silicone
surfactants used buffer solution pH=4, 7, 10 to observe the degradation of
products under acidic, neutral or alkaline conditions. The structure change
of these cleavage products was confirmed by IR and UV spectra analysis.
The fundamental surface activity including surface tension, foaming,
contact angle and viscosity was studied. The photocatalytic degradation
of modified silicone surfactants with UV light over titanium oxide was
investigated. Experimental results have confirmed that products were
slowly degraded by direct photolysis. However, the cleavable silicone
surfactant was easily photocatalytically degraded with UV irradiation in
the presence of TiO2. Addition of TiO2 to the reaction system
substantially increased the products splitting off of the water-insoluble of
silanol particles aggregate. All of the silicone-PEG surfactants showed
excellent water-repelling and the contact angle closed to 110°. It also
indicated that the silicone-PEG surfactants impart the new function of
water repellency effect for nylon fabrics was referred to as functional
surfactants.
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