Aromatic macromolecules

There are, however, numerous other less showy observations which give Insight into energy transfer of aromatic macromolecules. Some of these will be discussed in the following three sections, followed by a brief account on triplet-triplet annihilation. 

Cosmic abundances in the interstellar medium are derived by measuring elemental abundances in stellar photospheres, the atmospheric layer just above the stellar surface. Such measurements indicate the amount of elements available for the formation of molecules and particles. Cosmic dust models indicate that up to 80% of the carbon in the photon-dominated diffuse interstellar medium is incorporated into solid aromatic macromolecules and gaseous polycylic aromatic hydrocarbons (41,30). CO gas and C-based ice species (such as CO, CO2, CH3OH and others) may be responsible for up to -25 % of the carbon in cold dense interstellar regions. 

Another natural polymer type abundantly available is the polyphenolic lignin. This aromatic macromolecule which occurs in terrestrial plants is obtained... 

In the chemical modification of PS with MA, AA, EC, butadiene, and isoprene using cationic catalysis caused either destruction of macromolecules or the binding of functional groups to the aromatic ring. 

As it will be shown the presence of an aromatic amino group in the macromolecule of modified PAN offers new possibilities for graft copolymers without the formation of a homopolymer. 

However, dendrimeric and hyperbranched polyesters are more soluble than the linear ones (respectively 1.05, 0.70, and 0.02 g/mL in acetone). The solution behavior has been investigated, and in the case of aromatic hyperbranched polyesters,84 a very low a-value of the Mark-Houvink-Sakurada equation 0/ = KMa) and low intrinsic viscosity were observed. Frechet presented a description of the intrinsic viscosity as a function of the molar mass85 for different architectures The hyperbranched macromolecules show a nonlinear variation for low molecular weight and a bell-shaped curve is observed in the case of dendrimers (Fig. 5.18). 

Sheiko SS, Moller M (2001) Hyperbranched Macromolecules Soft Particles with Adjustable Shape and Capability to Persistent Motion. 212 137-175 Shen B (2000) The Biosynthesis of Aromatic Polyketides. 209 1-51 Shinkai S, see James TD (2002) 218 159-200 Shirakawa E, see Hiyama T (2002) 219 61-85 Shogren-Knaak M, see Imperial B (1999) 202 1-38 Sinou D (1999) Metal Catalysis in Water. 206 41-59... 

Poly (anhydrides) based on aliphatic-aromatic diacids. Macromolecules. In Press. 

In 1993, Scherf and Chmil described the first synthesis of a ladder-type poly(pflra-phenylene-czs-vinylene) (116) [138]. On the one hand, ladder polymer 116 represents, a planar poly(phenylene) containing additional vinylene bridges on the other hand, it is a poly(phenylenevinylene) with aryl-aryl linkages in the polymeric main chain. The target macromolecules, as fully aromatic ladder polymers, are composed of all-carbon six-membered rings in the double-stranded main chain (an example of angularly annelated poly(acene)s). 

Remarkable concentration of the photon energy absorbed by aromatic dendritic scaffold toward the focal point (herein called antenna effects ) is one of the most distinct features of the dendritic macromolecules. Poly(benzyl ether) (PBE) dendron [1] has been studied most extensively as an efficient antenna dendron. Careful studies have revealed the crucial role of the symmetric dendritic structure for the antenna effect. 

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