Resin hydrophobic-hydrophilic balance

Note that the highest IDT was obtained with the cyclopenta-methylenehydantoin resin derived from cyclohexanone. It is tempting to speculate that this inflexible alkylene moiety was ineffective in shielding the hydantoin ring, but subsequent comparison of the hydrophobic-hydrophilic balance of amine-cured resins appeared to rule out this explanation probably the stiff spiro structure contributed to the high Tg, just as it contributed to the high melting point of the resin itself (lie). 

Since the hydrophobic-hydrophilic balance of amine-cured resins was so sensitive to alkyl substituents on the hydantoin ring, it is not surprising that it was also sensitive to the hydrocarbon moieties of the amine curatives. The range of behavior depended on the resin substituents. For example, the already hydrophobic ethyl amyl substituted Resin Ilk showed moderate but significant increases in hydrophobicity when cured with cycloaliphatic, highly branched aliphatic, or formulated aromatic amines. See Table V. 

Figure 5 shows the uptake of a series of tetralkyl-ammonium and the benzyltri-methylammonium cations as compared with potassium by sulfonic acid resins of differing hydrophobic-hydrophilic balance. 

The surfactant selection determines the emulsion properties, such as stability, particle size, viscosity, and internal phase content. A correct balance between the hydrophobic and hydrophilic character of the emulsifier is necessary for minimizing the surfactant concentration at the resin-water interface. The surfactants used in resin emulsification can be ionic (in most cases anionic), nonionic, polymeric, or a combination of these. 

Steric factors - branching at or close to the hydantoin ring - raised the glass transition temperature while maintaining the shielding effect. Amines of different structures were used as room temperature curatives with a few representative resins, to observe the effect on hydrophilic-hydrophobic balance. Solvent effects were examined on aromatic amine-cured resins the most hydrophilic cured system proved to have the broadest range of lyophobicity. 

Aliuniniiun trihydrate (ATH) should continue to experience strong growth but there is much competition from mineral suppliers all anxious to launch special precipitated grades and those wilh new surface treatments to make them more effective. The drive is the requirement for lower loadings to preserve the balance of mechanical and physical properties for which the particular plastic system has been chosen. The treatment of hydrophilic ATH particles with hydrophobic coatings, such as fatty acids or silanes, provides for more uniform dispersion in the hydrophobic plastic resins. 

Hydrocarbon groups have the opposite effect because they are hydrophobic so a lot of hydrocarbon (as, for example, in a polybutadiene resin) will help in increasing the film resistance. This cannot be taken too far. Too much hydrocarbon will make the emulsion unstable, thus it will be impossible to produce a practical system. Thus, a balance needs to be found between the hydrophilic and hydrophobic portions of the polymer molecule. 

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