General Aspects

Manaresi, P.; Munari, Andrea

doi:10.1016/b978-0-08-096701-1.00143-9

Cited by 3 publications

(1 citation statement)

References 52 publications

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“…For example, (Ci8H37NHC(0)0)i.4(Et0)33i and (C18H37NHC- [jj] (dL/g) calculated by extrapolation of , /c as a function of concentration to zero concentration. 6 [jj] (dL/g) calculated by extrapolation of In ?jrei/c as a function of concentration to zero concentration.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and solution properties of hydrophobically modified ethoxylated urethanes with variable oxyethylene spacer lengths

Kaczmarski¹,

Glass²

1993

Macromolecules

137

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The influence of the oxyethylene spacer length between terminal hydrophobes of hydrophobically-modified ethoxylated urethanes (HEURs) is examined through the synthesis of two series of welldefined terminally-modified HEUR thickeners. In the first series, octadecyl isocyanate is reacted with poly (oxyethylene) (POE) of varying molecular weight. In the second synthesis, excess isophorone diisocyanate is reacted with POE to prepare an isocyanate functional precursor, followed by reaction of the terminal isocyanate group with nonylphenol. Viscous aqueous solutions are obtained with only partial terminal modification of POE; with full terminal modification swollen gels are realized. At moderate concentrations the phase separation of HEUR thickeners is dependent on the size of the hydrophobe and the number of oxyethylene units between the hydrophobes. In both series of HEURs, the critical aggregation concentration is lowest when 500 oxyethylene units separate the terminal hydrophobes. In the presence of surfactant, both anionic and nonionic, the fully-modified HEURs also exhibit a maximum in viscosity when the spacer is ~500 oxyethylene units. The viscosities realized in both HEUR series are equal or greater (with smaller HEUR oxyethylene spacings) with the nonionic surfactant relative to the anionic surfactant, sodium dodecyl sulfate.

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Section: Resultsmentioning

confidence: 99%

Synthesis and solution properties of hydrophobically modified ethoxylated urethanes with variable oxyethylene spacer lengths

Kaczmarski¹,

Glass²

1993

Macromolecules

137

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Formation of pore‐filled microfiltration membranes using a combination of modified interfacial polymerization and grafting

Childs

Weng

Kim

et al. 2001

J. Polym. Sci. A Polym. Chem.

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A novel method of fabricating pore‐filled membranes has been developed by coating a hydrophobic polyolefinic microfiltration membrane with polyethylenimine (PEI) to produce a chemically active surface. An evaporative coating technique was used to coat the internal surface of a polyolefinic membrane with PEI in chloroform (CHCl3). The coated PEI was then crosslinked by naphthalene‐1,4‐disulfonyl chloride in carbon tetrachloride (CCl4). The incorporation of the PEI coating changed the properties of the base membrane from hydrophobic to relatively hydrophilic; the nitrogens could be titrated, and the coating could not be washed out. 4,4′‐Azo‐bis(4‐cyanovaleryl chloride), a heat‐sensitive radical source, was incorporated into the coated membrane. The coated membrane, with incorporated azo compound, was heated to 75 °C in the presence of acrylic acid, 4‐(vinylpyridine), or styrene to give the corresponding grafted, pore‐filled membranes. The membranes exhibited hydraulic fluxes and pH valve effects consistent with molecular brushes grafted within the pores of the membranes. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 242–250, 2002

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Poly(p-phenylene sulfide) Synthesis: A Step-Growth Polymerization with Unequal Step Reactivity

et al. 1997

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The anomalous responses of M w to conversion and to comonomer stoichiometry, i.e., deviations from expected classic A−A + B−B step-growth polycondensation behavior, observed in poly(p-phenylene sulfide) synthesis from p-dichlorobenzene and sodium sulfide are shown to be a consequence of unequal rate constants for the growth steps. The polymerization is simulated by a computer model based on the step-growth polymerization concept and includes cyclization and side reactions. Rate constants and activation energies for the growth and side reactions were obtained by measurements of reaction rates of actual reaction intermediates or model compounds, while those for cyclizations were estimated.

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General Aspects

Cited by 3 publications

References 52 publications

Synthesis and solution properties of hydrophobically modified ethoxylated urethanes with variable oxyethylene spacer lengths

Synthesis and solution properties of hydrophobically modified ethoxylated urethanes with variable oxyethylene spacer lengths

Formation of pore‐filled microfiltration membranes using a combination of modified interfacial polymerization and grafting

Poly(p-phenylene sulfide) Synthesis: A Step-Growth Polymerization with Unequal Step Reactivity

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