Results 201 to 210 of about 2,946 (246)

Particle and Phosphate Removal Mechanisms with Prepolymerized Coagulants

1992
The efficiency of wastewater treatment by chemical coagulation depends on the efficiency of each stage: (1) coagulation/precipitation, (2) flocculation, and (3) separation. The efficiency of the coagulation/precipitation stage depends on many parameters including the raw water quality, the chemistry of the coagulant, physical parameters of the process,
Harsha Ratnaweera, Joachim Fettig, Hallvard Ødegaard   +2 more
openaire   +1 more source

NCO‐prepolymere aus diisocyanaten mit unterschiedlich reaktiven NCO‐gruppen

Die Angewandte Makromolekulare Chemie, 1984
AbstractEs werden zwei Verfahren zur Bestimmung des Verhältnisses der Geschwindigkeitskonstanten γ = k1/k2 bei der Urethanbildung aus Diisocyanaten mit unterschiedlich reaktiven NCO‐Gruppen beschrieben. Bei der Umsetzung mit einem großen Überschuß an n‐Butanol erfolgt sowohl bei 1,6‐Hexamethylendiisocyanat (HDI) als auch bei 3‐Isocyanatomethyl‐3,5,5 ...
O. Lorenz, H. Decker, G. Rose
openaire   +1 more source

Control of urethane prepolymerization from reaction kinetics and viscosity

Journal of Applied Polymer Science, 1973
A theory of the kinetics of consective second-order reactions has been generalized and used to interpret observations of toluene-2,4-diisocyanate reacting with polyoxypropylene glycol without diluent or catalyst to form a urethane prepolymer. The first reaction in the sequence has a second-order rate constant of 1.2 × 10−7 m3mole−1 sec−1 at 303°K with ...
Charles E. Chaffey, Samuel Orchanian
openaire   +1 more source

Approaches towards a technically feasible photoinitiated prepolymerization of methyl methacrylate

Chemical Engineering and Processing: Process Intensification, 2004
Abstract The photochemically initiated polymerization offers distinct advantages in controlling the molecular weights and the polydispersity of PMMA-prepolymers. Such prepolymers possessing a polymer content of up to 20% per weight are of a steadily increasing importance in industrial “casting-processes”. Experiments were performed in a batch reactor
S. Teixeira, R. Giudici, S.H. Bossmann, J. Lang, A.M. Braun   +4 more
openaire   +1 more source

COMPUTATIONAL AND SPECTROSCOPIC STUDY OF THE PREPOLYMERIZATION COMPLEX FORMATION IN THE TETRACYCLINE-BASED IMPRINTED POLYMER SYNTHESIS

Journal of Molecular Structure, 2023
Felipe de Jesús Anaya-Castro, Diana G. Aguilar-García, Rodolfo Gómez-Balderas, Emir A. Galván-García, V. Miranda-Soto, Antonio Tirado-Guízar, Adrián Ochoa Terán, G. E. Pina Luis   +7 more
semanticscholar   +1 more source

Phenolic Foams Toughened with Triethylene Glycol by In Situ Polymerization and Prepolymerization Processes

ACS Applied Polymer Materials, 2022
K. Tang, X. Tang, Xiaofeng Liu, Ailing Zhang, T. Ge, Yongjiang Li   +5 more
semanticscholar   +1 more source

High precision prepolymerization of propylene at extremely low reaction rates—kinetics and morphology

Chemical Engineering Science, 2001
A one-liter slurry phase polymerization reactor was set-up to carry out catalytic polymerizations of propylene at low reaction rates. The catalyst system used in this work was a fourth generation Ziegler–Natta catalyst, with tri-ethyl aluminum as cocatalyst and di-cyclopentyl dimethoxy silane as external electron donor.
Pater, J.T.M., Weickert, G., Loos, J.A., van Swaaij, W.P.M.   +3 more
openaire   +4 more sources

Prepolymerized vs. in situ-polymerized Fiber-reinforced Composite Implants – a Pilot Study

Journal of Dental Research, 2010
The aim of this study was to investigate bone response to bioactive fiber-reinforced composite (FRC) implants under two polymerization conditions. Glass-fiber-dimethacrylate composite was tested as prepolymerized cylinder-shaped FRC implants and as cylindrical FRC implants polymerized in situ with blue light transmitted and scattered by the glass ...
Ballo, A.M., Närhi, T.O., Akca, E.A., Ozen, T., Syrjänen, S.M., Lassila, L.V.J., Vallittu, P.K.   +6 more
openaire   +3 more sources

Telechele Prepolymere aus DGEBA und disekundären Diaminen. Unvernetzte Epoxid‐Amin‐Additionspolymere. 29

Acta Polymerica, 1990
AbstractDurch Additionsreaktion von disekundären Diaminen an DGEBA wurden α,ω‐Aminotelechele und glycidylterminierte Prepolymere erhalten. Mittels Elementaranalyse, M̄n (VPO)‐Werten, NMR‐Spektroskopie und HPLC‐Analyse wird die Struktur der Prepolymere belegt und die gesetzmäßige Oligomerverteilung nachgewiesen.
J. Klee, H.‐H. Hörhold, J. Raddatz
openaire   +1 more source

Preparation and Surface Properties of Low-Density Gels Synthesized Using Prepolymerized Silica Precursors

Langmuir, 2004
Properties of silica xerogels and aerogels synthesized using a number of prepolymerized silica precursors were probed by 29Si magic-angle spinning (MAS) NMR spectroscopy, the small-angle X-ray scattering (SAXS) method, the nitrogen adsorption method, and transmission electron microscopy (TEM) to show that xerogels with attractive textural properties ...
Julita, Mrowiec-Białoń, Andrzej B, Jarzebski, Lucjan, Pajak, Zbigniew, Olejniczak, Mirosław, Gibas   +4 more
openaire   +2 more sources