Reactive softeners

There are reactive softeners, some of which are N-methylol derivatives of long-chain fatty amides (10.241) while others are triazinyl compounds (10.242). The N-methylol compounds require baking with a latent acid catalyst to effect reaction, whereas dichloro-triazines require mildly alkaline fixation conditions. The N-methylol compounds are sometimes useful for combination with crease-resist, durable-press, soil-release and water-repellent finishes. In this context, the feasibility of using silane monomers such as methyltri-ethoxysilane (10.243), vinyltriethoxysilane (10.244), vinyl triace tylsilane (10.245) and epoxypropyltrimethoxysilane (10.246) in crosslinking reactions to give crease-resist properties and softness simultaneously has been investigated [492]. 

Reactive softeners Some softeners have functional groups that can react with the corresponding groups of some fibres, for example A-methylolated amines with the hydroxyl groups of cellulose (compare the mechanism of the crease resistance finish). The result is a very durable finish, combined with the typical advantages and disadvantages of this crosslinking chemistry, as discussed in Chapter 5. 

DANSIL 24 is a reactive softener for durable press fabric treatment. It is a stable, water dilutable silicone emulsion. Its principal use is as a softener with durable press resins. It Imparts increased wrinkle recovery, improved flex abrasion resistance and a soft lively hand to fabrics so treated. 

Furfural can be classified as a reactive solvent. It resiniftes in the presence of strong acid the reaction is accelerated by heat. Furfural is an excellent solvent for many organic materials, especially resins and polymers. On catalyzation and curing of such a solution, a hard rigid matrix results, which does not soften on heating and is not affected by most solvents and corrosive chemicals. 

Cationic polymerization of coal-tar fractions has been commercially achieved through the use of strong protic acids, as well as various Lewis acids. Sulfuric acid was the first polymerization catalyst (11). More recent technology has focused on the Friedel-Crafts polymerization of coal fractions to yield resins with higher softening points and better color. Typical Lewis acid catalysts used in these processes are aluminum chloride, boron trifluoride, and various boron trifluoride complexes (12). Cmde feedstocks typically contain 25—75% reactive components and may be refined prior to polymerization (eg, acid or alkali treatment) to remove sulfur and other undesired components. Table 1 illustrates the typical components found in coal-tar fractions and their corresponding properties. 

Chemical Reactivity - Reactivity with Water No reaction Reactivity with Common Materials Softens and dissolves many types of plastics Stability During Transport Stable Neutralizing Agents for Acids and Caustics Not pertinent Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Finally, two other experimental observations were addressed. First, the small increases in rate resulting from warming were suggested to be due to matrix softening at higher temperatures, and Ar appeared to be a less-rigid matrix than N2. Second, the tunneling rate constant for rotation of 11-endo to the reactive 11-exo conformer... 

The oils and waxes described as lubricants in section 10.10.1, as well as talc, can be used as softeners but have now been superseded by more effective products. These may be non-reactive or reactive and may be cationic, anionic, nonionic or amphoteric. Although many compounds have been patented, by far the most important are cationic quaternary ammonium compounds and various silicones. Until quite recently the field was led by the cationic types but there is now evidence that aminofunctional polysiloxanes have become the most important product group [482]. 

A product of this type will have over 50% of its weight derived from maleic anhydride. This very high content of reactive double bonds will lead to a very brittle solid when it is cross-linked with styrene. Without further modification, this solid material will have very high tensile moduli, probably over 600 kpsi, but a very low tensile elongation, way below 1 %. Such a brittle material obviously has only very limited applications. Thus, for most general-purpose applications, it is necessary to incorporate some chemically inert components to soften the polymer backbone. This will reduce the cross-linking density and improve the physical properties of the cured solid. 

With the growing level of control of copper CMP process comes the requirement for temperature control. Copper CMP is highly temperature sensitive, so hot slurry will enhance the removal of bulk copper. However, barrier metals are significantly less reactive (with the slurries currently available), so there is a significantly greater mechanical contribution to the removal of the barrier layer(s). Consequently, hot slurry is of little benefit for barrier layer removal and may soften the pad and aggravate metal dishing and dielectric erosion. 

The method depends upon the fact that even the most reactive radical can be permanently stabilized by trapping it in an inert matrix so that it is totally prevented from migrating to other reactive species. It may be studied at leisure, provided the trapping matrix is not allowed to soften sufficiently to permit migration of the radicals. 

There are two methods to soften (plasticize) polyurethanes. The first is to use reactive plasticizers such as long-chain hydroxyl or amine-based materials, and the second is to use a compatible nonreactive plasticizer such as DIOP or Benzoflex 9-88. 

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