This paper presents angular and spectral measurements of the functions that create a scattering matrix (Mtiller matrix). The investigations were carried out on monocultures of the unicellular phytoplankton ChZoreZEa vulgar-is, ChZoreZZu kesleri, and Chroococcus minor at scattering angles from 8" to 155" and at wavelengths of 488, 514, and 633 nm. Living cultures of phytoplankton as well as cultures treated chemically (boiled in 5% NaOH) and physically (ultrasound) were tested. These treatments alter the internal structures of the cells, and show that the altered structures modify the scattering matrix functional.

Laboratory measurements of light scattering on axenic cultures of the unicellular alga Chlorella vulgaris confirm multilevel light scattering by the cell (i.e. both by the outer cell membrane and the internal structure of the cell, as well as by its molecular structure). The technique of dynamic light scattering and analysis by the regulation method suggest that the light scattering phenomena is affected by particles of sizes corresponding either to the overall dimensions of the cell or to the dimensions of its internal structure. A correlation was found between the suggested sizes and the stage of physiological evolution of the culture. Three well‐known stages (adaptation, logarithmic and stationary growth) can be recognized easily in changes observed in the size distribution of the scattering centers as measured by the dynamic light scattering technique and in the shape changes of elements of the scattering matrix. The occurrence of cells containing large internal structure elements, such as autospores, affect elements of the scattering matrix, suggesting that cell structure should be taken into account as a scattering system producing rotatory polarization of the scattered light.

Acta Polymerica 40 (1989) Nr. 4 260 BLOSS, HERQETH et al.: Association of polyoxyeth y lene-polyoxypropylene block copolymers FLORY-HUGGINS parameter is a linear function of @ , for t h e range of 0.35 5 @ , 5 0.65: This result is in contrast t o investigations reported in t h e literature [7, 121, where t h e concentration dependence of x on @ , is neglected in all cases; b u t t h e values themselves are close t o t h e %-values presented above. ConclusionsT h e method presented permits t h e determination of t h e equilibrium distribution of liquid substances with a low molar mass in polymer dispersions using ultrasonic velocity data. T h e distribution coefficient can b e determined with a n accuracy of &0.5y0. This method is applicable t o all types of additives, polymers a n d dispersion media since no system is known which contains ingredients which all have t h e same ultrasonic velocities or elastic constants.T h e monomer concentration at t h e reaction locus a n d t h e diameters of t h e monomer swollen latex particles as well as the FLORY-HUGGINS parameter are determinable by this method. These quantities are of significant importance for t h e control of polymerization processes.Disadvantages of this method lie in t h e existence of a minimum polymer concentration of 5% i n dispersion media, which is nessesary t o detect t h e polymer by ultrasonic techniques, a n d in t h e inapplicability t o gaseous monomers under normal pressure (e.g. vinyl chloride, butadienej.Polymer Sci. 26 (1981) 1351.The water-solubility of triblock copolymers of poly(oxyethy1ene) and poly(oxypropy1ene) is caused by the binding of water to the oxygen of the OE units. Two water molecules are bound to one OE unit as can be derived from measurements of ultrasound velocity and density of the solutions. This binding is lost by increasing the temperature, and, therefore, the polymer precipitates from aqueous solution. The existence of polymeric associates can be detected by investigations of the viscosity as well as by static and dynamic light scattering. Assoziate yon Poly(oxyethyZen)-PoZy(oxypropylen)-Blockcopolymeren in wapriger L6sungDie Wasserloslichkeit von Triblockcopolymeren des Poly(oxyethy1ens) und Poly(oxypropy1ens) wird verursacht durch die Bindung des Wassers an den Sauerstoff der Oxyethylen-Einheiten. Aus Schallgeschwindigkeits-und Dichtemessungen an den Losungen kann abgeleitet werden, daS im Mittel zwei Wassermolekule je OE-Einheit gebunden sind. Temperaturerhohung fuhrt zum Aufbrechen dieser Bindung und damit zum Ausfallen des Polymers aus der Losung. Die Entstehung von Polymerassoziaten wird mit Viskositatsuntersuchungen sowie statischer und dynamischer Lichtstreuung nachgewiesen. Accoyuamu eonoJcmepoe noJcuoKCwmUnena c noJcuomunponuenoa 8 soanoa pacmsope PaCTBOpHMOCTL Tpm6JIOYHbIX COlTOJIHMepOB IIOJIHOKCH3THJIeHa C IIOJIHOKCIIIIpOII~JIeHOM B Bone BbI3BaHa CBH3bI-BaHHeM MOJIeKyJI BOAbI H a aTOMaX KHCJIOpOAa OKCM3THJIeHHbIX t?AHHHq. 113 H3MePeHHfi CKOPOCTEl3ByKa H IIJIOTHOCTH CJIeAyeT, YTO B CpeAHeM ABe MOJIeKyJ...

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The photodegradation of polystyrene (PS) in deoxygenated solutions of CCb and CHCl, by irradiation with ultraviolet light of wavelengths 1 2 270 nm is investigated by quasielastic and integral light scatte_ring techniques. Molar mass distributions w (M), number-and weight-average molar masses % and M , as well as the average number of chain scissions per macromolecule x ( t ) as a function of the time of irradiation t were determined. The results obtained prove that efficient photodegradation occurs in CCb-and CHC1,-solutions of PS, although measurable changes in molar mass of irradiated PS starts to occur only after several hours of irradiation.