feels out of control in the water," says Lennon.
The interactions were studied as a function of hydrophobe
length, concentration, and pH.
Table 1--Main Categories of Foam Control Products for Waterborne Coatings Foam Control Description Product Type Silicone 100% active polydimethyl siloxane (PDMS)-based Compounds materials Silicone Dilutions of PDMS compounds in water Emulsions Organically PDMS backbones with attached organic functionality Modified Silicones Synthetic Poiyol Typically, glycol carriers with silica and/or wax hydrophobes
Standard Mineral Hydrocarbon oil with silica and/or wax hydrophobes
Oil Enhanced Mineral Hydrocarbon oil with silica and/or wax hydrophobes
, Oil possibly with PDMS, organically modified silicones (OMS) and other additives Vegetable Oil Nonhydrocarbon oil with silica and/or wax hydrophobes
melamine, glycoluril) and polyethylene glycols followed by the incorporation of long chain hydrocarbon hydrophobes
Varying size/structure of hydrophobe
, similar HLB values - ethoxylates at 10.
Numerous factors, including hydrophobe
size and structure, HEUR molecular weight, hydrophobe
level, latex particle size and composition, and other coating formulation components, all contribute to the overall rheology profile of a given coating system and how the viscosity responds as a function of shear rate.
Tire subject of freeze-thaw stability in this context is addressed by Rhodia researchers who have developed new hydrophobically modified alkali swellable (HASP) in which the hydrophobes
are specially designed macromonomers.
At higher copolymer concentrations, the interface becomes saturated with copolymer molecules and the intermolecular aggregates start forming lots of micelles and providing a favorable environment for the hydrophobes
, and this concentration is so called critical micellar concentration (CMC).
Differences in properties range widely because of the polymerization kinetics and hydrophobe
The remaining two HEURs are synthesized (34) to provide pendant hydrophobes
in a comb architecture different from the terminal hydrophobe
found in a telechelic HEUR synthesis, and generally they build viscosity less efficiently with concentration than telechelic HEURs.
Tailoring HASE rheology through polymer design: Effects of hydrophobe
size, acid content and molecular weight," Wonjun Wu and Greg D.
Low-foam surfactants can have an alkyl phenyl hydrophobe
and would be classified as APEO surfactants or can be made to be APEO-free by using alkyl chain hydrophobes