Poly : 15-oligomer chains

The fluorescence excitation and emission spectra of the electrogenerated fused benzothiophene oligomers [poly(39) and poly(41)] show the existence of dramatic red shifts of the fluorescence maxima and important increases of the fluorescence intensity relative to the parent monomers. These results suggest the existence of extended electronic conjugation in the oligomer chains. Poly(39) and poly(41) showed a well-structured excitation band with maxima at about 335 nm and 395 nm, respectively. These excitation maxima are strongly red shifted by about 50 and 108 nm, respectively, against the 39 and 41 excitation spectra. The emission spectra are characterized by a relatively wide, poorly structured band, centered at 410 nm and 445 nm, respectively. These emission maxima also present dramatic red shifts relative to the emission spectra of the parent monomers. 

Anhydride-terminated poly(dimethylsiloxane) oligomers were synthesized by the acid-catalyzed equilibration of DiSiAn and octamethylcyclo-tetrasiloxane (D4) (Scheme III). A wide range of oligomer chain lengths (n = 1 to >100) were prepared in this manner and characterized by and Si NMR spectroscopy. 

Claes, L., J.P. Fran9ois, and M.S. Deleuze. 2001. Molecular packing of oligomer chains of poly (p-phenylene vinylene). Chem Physics Lett 339 216. 

Normally, a maaomonomer carries only a single oligomer chain. The combination of a terminal vinyl group with two polymeric chains has also been reported. In such an example, macromonomers consisting of a methacryloyl group as a polymerizable unit and two PS or poly(tert-butyl acrylate) (PtBA) chains were prepared in two steps as shown in Figure 3 (1) ATRP of styrene or tBA was initiated by a diinitiator, 1 -hydroxymethyl-1,1 -di [ (2-bromoisobutyryloxy)... 

The nature of the oligomer chain ends strongly influences the of poly (ether sulfone) ... 

Cu(II)-polymer complexes initiate radical polymerization and often show higher activity than the corresponding monomeric analogues. The systems of Cu(II) ion with nylon [97], a-aminocaproic acid [96], nylon oligomers [96], polyethylene-polyamine [98,99], pt)ly(vinylamine-co-vinyl alcohol) [100], and cellulose have been made by Imoto and Takemoto as initiation systems for free radical polymerization of vinyl monomers, such as methyl methacrylate (MMA). Inaki et al. reported that Cu(II)-polyvinylamine complexes in the presence of CCI4 in an aqueous solution showed higher activity as an initiator than Cu(II)-diaminopropane complex for the radical polymerization of methyl methacrylate, acrylonitrile, and styrene [101]. The pH dependence for activity indicates that the free amine groups on the poly(vinylamine) chain are involved in the catalysis. The initiation mechanism is proposed as follows [Eqs. (78-80)] ... 

V. Carlier, J. Devaux, R. Legras and D.J. Blundell, Extrapolation of short chain oligomers melting temperatures at infinite molecular weight, ]. Poly. Sci., Part B Poly. Pkys., 36 (1998) 2563-2571. 

---