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Group IVB-Containing Polydyes

The cyclopentadienyl derivatives of titanium, zirconium, and hafnium were first described by Wilkinson and coworkers in the early 1950s. These compounds have a tetrahedral geometry, possess a high degree of covalent character and behave like organic acid chlorides in condensation polymerization reactions. Group IVB metallocene-containing materials are known to be active catalytic sites and to offer potentially useful photonic and other properties.  [Pg.74]

A munber of dyes were examined. Since the usual mode of employed synthesis involves Lewis acid-base reactions, employing solution and interfacial systems, dyes that had two Lewis base sites were generally used. Reaction systems were employed that allowed the rapid room-temperature synthesis of the products while minimizing imwanted rearrangement and degradation. [Pg.74]

Another attraction for including dyes into polymers is the (potential) permanent, nonleaching nature of such polymer-containing dyes. This would allow a material that contains a polydye to remain colored for longer times even in solids such as plastics. Migration and loss of colorants occurs even in solids such as plastics. The ability to retain color or other important additive properties is especially important in marine coatings apphcations, where leaching and subsequent loss is aided by the ever present aqueous environment. [Pg.74]

The actual structures of dyes vary witii pH. This is shown in scheme 1 for fluorescein. [Pg.74]

For dyes with structures similar to fluorescein and sulphonephathalein, two types of reactive sites are present tinoughout much of the pH range. They can exist as acids or their conjugate bases, the RO and RCOO (for the fluorescein) or RSO3 (for the sulphonephthalein dyes). Since they react similarly, only the fluorescein [Pg.74]


See other pages where Group IVB-Containing Polydyes is mentioned: [Pg.73]    [Pg.74]    [Pg.75]    [Pg.77]    [Pg.79]    [Pg.73]    [Pg.74]    [Pg.75]    [Pg.77]    [Pg.79]    [Pg.80]   


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Group-IVB

Polydye

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