As a design of biodegradable water-soluble polymer, high molecular weight polycarboxylates containing biodegradable segments were prepared and their biodegradability and builder performance in detergent formulations were evaluated. Both natural polysaccharide derived from polycarboxylates containing unreacted sugar residues and chemically synthesized polycarboxylates containing poly (vinyl alcohol) blocks as a biodegradable segment showed similar tendencies. That is, the biodegradability and builder performance of the polycarboxylates varied inversely with the biodegradable segment content. However, the builder performance was improved when more a polymeric carboxylate was used in the detergent process. The minimum required structure needed as a biodegradable segment in the polymer chain with respect to the configuration and block length were clarified using the specific microbes and enzyme. High molecular weight polycarboxylates containing ester, ether and carbonyl groups were also evaluated and compared for biodegradability and builder performance. Biodegradability and builder performance were correlated with the molecular weight in order to develop biodegradable functional polymers by the reduction of their molecular weight to the extent that the environmental microbes can assimilate them.

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Values for the ultimate biodegradability of alkyl polyglycoside (APGs) were determined using three different microorganisms. Acute toxicity tests were performed on aquatic organisms in fresh and sea water.
The biodegradability of APG based on biochemical oxygen demand (BOD) and dissolved organic carbon (DOC) was 7389 % and 74>99 %, respectively. High performance liquid chromatographic (HPLC) and gel permeation chromatographic (GPC) analyses indicated the disappearance of nearly all test substances. Branched alcohols and differences in alcohol chain length in the APG chemical structure are considered to be without effect on biodegradability. APGs were shown to rapidly and ultimately undergo biodegradation in an aquatic environment.
The 96 h LC₅₀ values of APG were 96115 mg/L for fresh water red killifish (Oryzias latipes) , 50 mg/L for sea water adapted red killifish and 15 mg/L for mysid shrimp (Mysidopsis bahia) , indicating relatively weak toxicity among surfactants.
It follows from the present results that ecotoxicological risk of APGs is likely quite low and APGs may have good environmental compatibility in the aquatic ecosystem.

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Effects of electrolytes (LiC1, NaCl, KCl, LiNO₃, MgCl₂, CaCl₂, FeCl₃ and AlCl₃) on the stability of monodisperse O/W emulsion was investigated using an aqueous sodium dodecyl sulfate (SDS) solution/ kerosine system.
The rate constants (k₂) for decrease in emulsion droplet number decreased with increase in the concentration of all electrolytes used and indicated a minimum value at a certain concentration of each electrolyte. A maximum zeta potential only for the emulsion droplet with a univalent cation electrolyte was obtained at the same concentration of electrolyte which gave minimum k₂, but no correspondence was observed with various electrolyte concentrations of bi-and trivalent cations. The oil separation by centrifugation of the emulsion and interfacial tension of the aqueous SDS solution/kerosine system both decreased with increase in electrolyte concentration.
It follows from the present results that increase in electrolyte concentration in bulk solution causes decrease in electrostatic repulsion and increase in the resistance of the membrane to coales, these cause k₂ to take on a minimum value.

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Effects of such n-type semiconductors as TiO₂ (anatase, rutile or surface-modified TiO₂ and Pt-loaded TiO₂), ZnO, WO₃ and MoS₂ on the photodegradation of anionic DBS and cationic BDDAC surfactants, and related model compounds were examined in the present study. The anatase form of TiO₂ showed greater photocatalytic activity than the rutile form. Noble-metal loaded catalysts (e. g., TiO₂/Pt) were less photooxidative than the naked anatase TiO₂ catalyst, possibly due to suppression of electron transfer of O₂ to give O₂, namely photoreduction. The ZnO semiconductor catalyst decomposed DBS more rapidly than anatase Ti0₂. The photocatalytic activity of the other semiconductors examined (WO₃ and MoS₂) was only slight in each case.

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The influence of sodium polyacrylate (Na-PAA) on the deposition of dispersed polystyrene (PS) latex particles on cotton and nylon-6 fibers in water was studied from the standpoint of interaction energy between latex particles and fibers. The deposited amount and rate of deposition of PS latex particles on the fibers in the presence of Na-PAA were less than when Na-PAA was absent, particularly in the case of cotton fibers. This inhibitive action of Na-PAA on the deposition of PS latex particles on both fibers was slightly more effective in the case of Na-PAA with high molecular weight than with low molecular weight. The above-mentioned function of Na-PAA on cotton fibers may possibly be due primarily to steric repulsive interactions, since total interaction energy (V_T) due to electrostatic and van der Waals' forces between latex particles and fibers did not increase by the addition of Na-PAA. And the function of Na-PAA on nylon-6 fibers may be due primarily to steric repulsive interactions similar to those noted cotton fibers, although the contribution of electrostatic repulsive interactions must be taken into consideration.

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Interactions between L-α-phosphatidylglycerol sodium salts and water molecules were examined primarily with a differential scanning calorimeter (DSC) and surface pressure meter. With an increase in alkyl chain length of L-α-phosphatidylglycerol sodium salts, stability of the coagel phase relative to that of the gel phase increased due to decrease in the dissociation of counterions (sodium ions). Monolayers of L-α-phosphatidylglycerol sodium salts (PG-Na) were readily converted to expanded monolayers with NaCl, and the temperature at which only expanded monolayers formed was in good agreement with a gel-lamella crystalline transition temperature (Tc). The molecular orientation of the PG-Na monolayer was shown in some causes to differ with that of its bilayer.

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Keratin was hydrolyzated by calcium hydroxide to obtain hydrolysis products. The foaming components constituted a fractionated portion of keratin hydrolysate by membrane ultrafiltration.
Foam height and stability of the fraction were related to the moleculer weight of each fraction. Fractions with molecular weights (FMW) range from 5, 000 to 10, 000 had the highest foam heights and the greatest foam stability. Those with FMW below 5, 000 had the lowest foam height and least foam stability. Fractions with FMW above 10, 000 differed somewhat from each other in foam height and foam stability.

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A simple and rapid spectrophotometric method was developed for the determination of sodium dodecyl sulfate (SDS). The method was based on formation of the SDS- [Copper (II) -1, 10-phenanthroline] ion pair and extraction into isobutyl methyl ketone (MIBK). The ion pair in MIBK was reduced with 1-butanethiol to form an intensely colored copper (I) complex. By this method, the overall concentration of SDS can be determined indirectly from the absorbance of copper (I) complex formed in MIBK. The calibration curve was linear over the range of the detection limit from 8.3 × 10^-7 to 6.3 × 10^-5 M of SDS. The relative standard deviation of nine successive determinations was 1.02 % at 2.5 × 10^-5 M of SDS. The sensitivity of the proposed method is comparable to that of the indirect atomic absorption method for SDS which is accepted as a highly sensitive method.

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Lipids of seven edible pulses in Nepal were examined. Total lipid content range was determined as 1.814.7 %. Major components of total lipids were triacylglycerols, constituting 7576 % of total lipids of soybeans and chick pea. The amounts of phospholipids present in grams ranged from 4447 %. Pigeon pea and yellow gram contained greater amounts of free fatty acids compared with the other species of pulses. Fatty acid compositions of soybean and chick pea were virtually the same, in contrast pigeon pea which contained less C_{18 : 1} and more C_{16 : 0}. Black gram contained the most C_{18 : 3}, over 50 % of the total. The lipids of pigeon pea and grams containing large amounts of free fatty acids showed very high TBAV and COV. It follows from the present results that pluses, split and without seed coat, may possibly undergo oxidation more rapidly.

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