Acenaphthylene copolymers

Fig. 34. Plot of 3 vs fg (see text) for poly acenaphthylene copolymer series...

Furyl methyl ketone was also tried with a series of olefins inhibition was operative in all systems and only traces of a copolymer with acenaphthylene were isolated at the end of a run which lasted several days. These observations are compatible with the higher basicity of this ketone compared with that of the corresponding aldehyde. 

The photocycloaddition of maleic anhydride to acenaphthylene has been studied by Hartmann and Heine.(107a> Irradiation of acenaphthylene in the presence of maleic anhydride in light-atom solvents (dioxane, acetone, or acetonitrile) yields only dimers or copolymers of acenaphthylene. In heavy-atom solvents (dichloromethane, dibromomethane, or iodomethane), however, dimerization is suppressed and cycloaddition with maleic anhydride predominates ... 

The products of polyethylene modification are mixed Mock and graft copolymers of three dimensional structures (with acrylic acid, methacrylamide and acrylonitrile) or linear structures (acenaphthylene and maleic anhydride). This is again consistent with the nature of the monomers and the activity of their radicals. 

The original objective in preparing emulsion polymers from the 2,6-dichlorostyrene and acenaphthylene was to obtain polymeric fillers of higher Tg than that of polystyrene. It was also presumed that these fillers would not be bonded chemically to the rubber during vulcanization and that the copolymers with butadiene would enable such bonding to be effected. Actually, the polydichlorostyrene and polyacenaphthylene did become bonded to the rubber, as indicated by the inability to extract most of the filler by solvents. The final result was that the copolymers with butadiene served merely as fillers of lower Tg than the above homo-... 

The principal difference between considerations of fluotescenre behaviour of acenaphthylene polymers VI and those of the photophysical characteristics of vinylaro-matic polymers is that whilst the latter sterns may form excimers throu interactions between nearest-neighbour chromophores on the polymer chain, steric restrmnts preclude such a mechanism in polymers of acenaphthylene It has been suggested that the dominant mechanism for excimer formation in acenaphthylene derived systems involves interactions between next to nearest nei bours. Such a proposal has been validated for copolymers of acenaphthylene with methyl methacrylate and methyl acrylate and is reinforced by the observation of excimer emission in alternating copolymers incorporating acenaphthylene chromophores in steady state excitation. 

Examination of the data in Table 8 reveals that T3 (and hence X3) is a function of the intramolecular chromophore concentration. In previous studies of vinyln h-thalene copolymers X3 has been found to vary linearly with the mde fraction of aromatic, fg. Figure 34 demonstrates the reasonable fit attained in such a plot for the acenaphthylene/methyl methacrylate stem. However, unlike the vinylnaphthylene copolymer systems, the linear fit of X3 to fg as a concentration term is not unique. 

Table 8. Decay parameters for i33o(t) for copolymers of acenaphthylene with methyl metha-...

Table 9. Rate-constants for decay in acenaphthylene - methylmethacrylate copolymers.

Phillips, D., Roberts, A. J., Soutar, I. Transient decay studies of photophysical processes in aromatic polymers, III. Concentration dependence of excimer formation in copolymers of acenaphthylene and methyl methacrylate. Eur. Polym. J. 17,101 (1981)... 

Table I. Ratio of Quantum Efficiencies of Excimer and Normal Emission in Acenaphthylene Homopolymer and Equimolar Copolymers Comonomer IdZIM—...

Excited states and energy migration by way of excitons have been studied in random copolymers of acenaphthylene (ACN) with acrylonitrile (AN), methacrylonitrile (MAN) and 2-vinyl napthalene (2VN). Also ACN was copolymerized with vinyl acetate and hydrolyzed to give free hydroxyl groups. 

The hydroxylated copolymers, poly(acenaphthylene-co-vinyl alcohol), were reacted with the following acyl chlorides 1-naphthoyl, 2-naphthoyl, benzoyl and cinnamoyl. The latter polymers contain an ester group as a spacer between the main chain and one of the fluorophores. The choice of an ester group as a connecting unit between the polymer chain and fluorophore is probably a poor one since it is known that carbonyl groups easily form triplets and photo-Fries rearrangements can occur (2). 

A copolymer containing a dimethylsiloxy spacer was prepared by reacting poly(acenaphthylene-co-vinyl alcohol) with dimethyldichloro-silane followed by reaction with 2-naphthol. (See Figure 1). 

Figure 1. Copolymers of acenaphthylene (a) poly(ACN-co-MAN) (b) poly(ACN-co-2VN) (c) poly(ACN-co-vinyl ester) where acyl is benzoyl, cinnamoyl, 1-naphthoyl and 2-naphthoyl (d) poly [ACN-co-dimethyl-(2-naphthoxy)-vinyloxysilane].

Fluorescence polarisation studies on acenaphthylene labelled polyacrylic acid has demonstrated complexation occurs with polyethylene oxide to give a tightly packed and sterically restricted conformation SS. Neutralisation of the acidic groups restored the polarisation of the fluorescence and together with time resolved fluorescence analysis indicated that the motion of the probe is anisotropic. Solvent partitioning has been observed between glycol methacrylate copolymers from the fluorescence anisotropy changes of... 

For example, the excessive addition of sensitizer can result in crystallization of the sensitizer. Some sensitizers, even when present in low concentrations can result in over-sensitization of the composition, in that the photocurrent generated upon exposure will persist comparatively long after the illumination ceases. As an alternative to the sensitization by additives, intramolecular charge transfer complexes have been proposed, where the electron donor and electron acceptor functions are located along a common vinyl backbone. Examples are nitrated vinyl polymers of poly-(acenaphthylene), poly(9-vinylcarbazole) and poly(l-vinylnaphthalene), copolymers from 3,6-diphenyl-vinylcarbazoleand 3,6-dinitro-9-vinylcarb-azole. ° and copolymers from NVK and iV-vinylphthahntide. ... 

Phillips D, Roberts AJ, and Soutar I. A time-resolved fluorescence spectroscopic study of excimer formation in polyacenaphthylene and an alternating acenaphthylene/maleic anhydride copolymer. J. Polym. Sci. Polym. Lett. 1980 18 123-129. 

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