Phenylene polymers

Scheme 64 Poly(l,4-phenylene) polymers by electroreduction of aryl halides.

This variant can be used for the preparation of dendronised poly(p-phenylene) polymers [50]. 

Hereby, poly(p-phenylene) polymers containing ether and carbonyl linkages in the polymer backbone are accessible. By polymerization of the AB2 monomer 3,5-dibromobenzene boronic acid in a biphasic aqueous/organic medium, Kim and Webster obtained hyperbranched polyphenylenes [233]. Suzuki polycondensation in aqueous systems has proven to be a versatile method, which has been applied to the synthesis of various polymer types ]234]. 

An ingenious way to create poly(phenylene) polymers with metals in the backbone is to use a coordination polymer strategy in which an oligophenylene substituted at each end by a terpyridine ligand can react with a metal center to yield a polymer. An... 

Mor Morgan, S. E., Misra, R., Jones, P. Nanomechanical and surface frictional characteristics of a copolymer based on benzoyl-1,4-phenylene and 1,3-phenylene. Polymer 47 (2006) 2865-2873. 07Ehr Ehrenstein, G. W., Pongratz, S. Bestandigkeit von Kunststoffen. Carl Hanser Verlag, Munich, 2007. 

FIGURE 5.8 Absorption, photoluminescence emission, and photoinduced absorption spectrum of a fiilly planarized ladder-type poly(para-phenylene) polymer film. The inset shows the actual chemical structure. 

Increasing the number of phenyl rings in a bis(2-thienyl)phenylene polymer is shown to have little effect on the resulting colors or bandgap of the polymer film. For example, poly-4,4 -bis(2-thienyl) biphenyl (59a) is transmissive yellow when neutral and green when oxidized [175,191]. Even when the... 

Reynolds, J.R., A.D. Child, J.R Ruiz, S.Y. Hong, and D.S. Marynick. 1993. Substituent effects on the electrical conductivity and electrochemical properties of conjugated furanyl phenylene polymers. 

Irvin, D.J. and J.R. Reynolds. 1998. Tuning the band gap of easily oxidized bis(2-thienyl)- and bis(2-(3,4-ethylenedioxythiophene))-phenylene polymers. Polym Adv Technol 9 260-265. 

The effect of moisture on the p relaxations in amorphous phenylene polymers is well documented (93-95) for many of the systems cited previously. For example, Allen and co-workers (93) determined that both the dielectric and mechanical P relaxations in polysulfone, polycarbonate, polyphenylene oxide, and polyether sulfone were dependent on the water content of the samples. In addition, the amount of water absorbed depended on the polarity of the molecule. The effect of moisture on the dielectric p process in these polymers appears to be greater than for the mechanical loss process, as illustrated in Figures 41 and 42 (93). 

The polymers studied by Allen and co-workers (93) are modestly polar with maximnm moisture uptakes of less than 1%. In more polar phenylene polymers such as polyimides (94) and poly(amide-imide)s (92), the mechanical fi relaxation shows a more significant effect becanse of the larger amoimts (1.5 to >4%) of moisture absorbed. 

For the conductivity of the corresponding digermylene phenylene polymer, only poly[p-l,2-(dimethyldi-phenyldigermylene)phenylene] (33) has been reported. This polymer can be prepared by the similar method to... 

Figure 5.18 Five different poly(m-phenylene) polymers.

Poly(borazylene) polymers, such as shown below, composed of linked borazine rings analogous the organic poly(phenylene) polymers, were of particular interest because of their potentially high ceramic yields (95%) and their close structural relationship to boron nitride. 

Table II. The repeat units for the phenylene polymers cited in Fig. 23.

Nakabayashi K., Matsumoto K., Shibasaki Y, Ueda M., Synthesis and properties of sulfonated poly(2,5-diphenethoxy-p-phenylene). Polymer, 2007,48(20), 5878-5883. 

Poly(irainoisophthaloyl Dimethyl formamide 25 1,3- and 1,4-phenylene polymers 160... 

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