Hydrophobically modified acrylics

The viscosity emphasized in this chapter, called elongational or extensional viscosity, was originally designated (34) tensile viscosity. When this bulk-phase parameter is near the interface, its two-dimensional equivalent is called the surface dilational viscosity. The importance of this parameter in the foaming of coatings, which arises from differences in surfactant structures, has been discussed (35). In cosmetic applications, foam and gel structures are important and probably reflect the reason the hydrophobically modified acrylic acid polymers were emphasized in the last section of Ghapter 7. 

GOS Gosselet, N.M., Borie, C., Amiel, C., and Sebille, B., Aqueous two-phase systems from cyclodextrin polymers and hydrophobically modified acrylic polymers, J. 

Table 3 Various Hydrophobically Modified, Acrylate-Based Associative Thickeners...

It is not unreasonable to expect that aqueous polymer dispersions will be effective in gels and mousses. Furthermore, the technology of hydrophobically modified acrylate thickeners discussed in Section II.A.3.a, useful for suspending latex particles, fits naturally into fixative gels. 

The chemistry available to design these hydrophobically modified acrylics is quite extensive. 

Chem. Desaip. Hydrophobically modified acrylic polymer emulsion Ionic Nature Anionic... 

Hydrophobe-modified copolymers of acrylate esters with acryflc or methacryflc acid are finding increasing use as high quality thickeners for both trade sales and industrial paints (186). Formulations thickened with these unique water-soluble polymers show excellent flow and leveling characteristics. 

The hydrophobe modification of acrylic acid represents an important class of hydrophobe-modified thickeners prepared by a chain-growth free-radical process. They differ slightly from other examples in that these products are generally cross-linked. 

Hydrophobically Modified Alkali-Swellable Emulsions. The hydrophobe modification of acrylic acid represents an important class of... 

Acrylics Synthetic, hydrophobic Modified polyacrylonitriles Anionic... 

A novel graft copolymer of hydrophobically modified inuhn (INUTEC SPl) has been used in the emulsion polymerisation of styrene, MMA, butyl acrylate, and several other monomers [8]. All lattices were prepared by emulsion polymerisation, using potassium persulphate as initiator, and the z-average particle size was determined using PCS electron micrographs were also recorded. 

Both of the types of polymer mentioned above can be modified by the incorporation of hydrophobic monomers onto the essentially hydrophilic acrylate backbone. The effect of this is to modify their characteristics by giving them so-called associative properties. These hydrophobes can interact or associate with other hydrophobes in the formulation (e.g., surfactants, oils, or hydrophobic particles) and thus build additional structures in the matrix [3-11]. These associative polymers are termed cross-polymers when they are based on carbomer-type chemistry [12] and hydrophobically modified alkali-soluble emulsions (HASEs) when based on ASE technology. 

The concept of polymeric soil release agents has been around for well over 25 years. The initial polymer chemistries (polyethylene terephthalate-polyoxyethylene terephthalate, PET-POET) were designed to deposit on fabrics and facilitate oily soil removal upon subsequent washing [98,133,134], The limitation of this chemistry was its effectiveness on synthetics (polyester) alone, with limited benefits being observed on cotton and synthetic blends. In recent years the focus has shifted to delivering soil release on cotton. Two classes of polymer chemistries have been disclosed in the recent patent literature for cotton soil release one based on hydrophobically modified polycarboxylates derived from acrylic acid and hydrophobic comonomers at defined molar ratios [188] and the other based on modified polyamines [189-193],... 

FIG. 6 Emulsion type diagram of ra-dodecane-water emulsions ( = 0.5) stabilized with hydrophobically modified poly(sodium acrylate)s effect of changing the degree of grafting and type of the graft (single versus twin-tailed). Salt is used as a tool to estimate the copolymer HL properties. (From Ref. 152.)... 

FIG. 11 Pseudophase diagram for 30 wt% cyclohexane in water stabilized by PAA (Carbopol 980). The c values are shown as the curve drawn in the bottom left-hand corner of the diagram. (Reprinted from Colloids and Surfaces A Physicochem Eng Aspects, 88, Lockhead RY, Rulinson CJ, An investigation of the mechanism by which hydrophobically modified hydrophilic polymers act as primary emulsifiers for oil in water emulsions. 1. Poly(acrylic acids) and hydroxyethyl celluloses. 27-32, Copyright (1994), with permission from Elsevier Science.)... 

Only a few studies about aqueous films of amphiphilic random polyelectrolytes are reported in the literature. Millet et al. [239-241] have investigated by x-ray reflectivity the behavior of vertical free-standing films (Figure 29) of a series of hydrophobically modified poly(acrylic acid) sodium salt (HMPAANa) and poly(acrylic acid) (HMPAAH). The chemical structure of the polymer was presented in Sec. II.C (Eq. 2a). One of the aims of this work was to determine the microscopic structure of the films to explain the (macroscopic) stability behavior of the dodecane-in-water emulsions studied by Perrin et al. [188,189], who used the same series of amphiphilic polyelectrolytes as primary emulsifiers. The aqueous polyelectrolyte films have been used as model systems for the interstitial films separating two neighboring oil droplets of an emulsion creamed layer. The authors have assumed that the oil/water interface encountered in emulsions was suitably described by the air/water interface of the films. The HMPAANa and HMPAAH co-... 

Lochhead RY, Davidson JA, Thomas GM. Poly(acrylic acid) thickeners. The importance of gel microrheology and evaluation of hydrophobically modified... 

Lochhead RY, Rulinson CJ. An investigation of the mechanism by which hydrophobically modified hydrophilic polymers act as primary emulsifiers for oil in water emulsions. 1. Poly(acrylic acids) and hydroxyethyl celluloses. Colloids Surfaces A Physicochem Eng Aspects 1994 88 27-32. 

Perrin P, Lafuma F, Audebert R. Emulsions stabilized with hydrophobically modified poly(acrylic acid). Progr Colloid Polym Sci 1997 105 228-238. 

Wang TK, Iliopoulos I, Audebert R. Aqueous solution behavior of hydrophobically modified poly(acrylic acid). In Shalaby SW, McCormick C, Butler GB, eds. Water-Soluble Polymers Synthesis, Solution Properties, and Applications. ACS Symposium Series 467, 1991 218-231. 

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