Thermally stable polymers groups containing

Research activities in the area of PODs containing aromatic groups have been centered around the production of highly processible, soluble, and thermally stable polymers. In this particular class of PODs, the imide-and phenylene-containing backbones have been widely explored. 

Similarly, mixtures of imide oligomers containing BCB groups and those containing maleimide groups were shown to polymerize at moderate temperatures of 200-250 °C to give thermally stable polymers [95]. 

To clarify the mechanisms of plastic flow of linear-chain polymers we also consider polyimides (PIMs), which make up a large family of stiff and thermally stable polymers of outstanding performance (Bessonov et al. 1987). Polyimides contain cyclic imide groups as shown in Fig. 2.4 in the main chain. From this very... 

A large variety of bisimides and polymers containing maleimide and citraconimide end groups have also been reported (21—26). Thus polymers based on bisimidobenzoxazoles from the reaction of maleic anhydride and citraconic anhydride with 5-aniino-2-(p-aniinophenyl)benzoxazole and 5-aniino-2(y -aniinophenyl)benzoxazole are found to be thermally stable up to 500°C in nitrogen. 

Carboxymethylcellulose, polyethylene glycol Combination of a cellulose ether with clay Amide-modified carboxyl-containing polysaccharide Sodium aluminate and magnesium oxide Thermally stable hydroxyethylcellulose 30% ammonium or sodium thiosulfate and 20% hydroxyethylcellulose (HEC) Acrylic acid copolymer and oxyalkylene with hydrophobic group Copolymers acrylamide-acrylate and vinyl sulfonate-vinylamide Cationic polygalactomannans and anionic xanthan gum Copolymer from vinyl urethanes and acrylic acid or alkyl acrylates 2-Nitroalkyl ether-modified starch Polymer of glucuronic acid... 

Polysilanes containing phenyl groups are thermally stable up to 350°C while methylmethoxypoly-silanes without phenyl groups decompose at 250 - 300°C. When methylmethoxyphenylpolysilanes are heated to 350°C methylmethoxysilanes distil off and a polymer is formed which is nearly free of methoxy groups. In contrast to the thermal reaction of polydimethylsilanes no polycarbosilane structures can be observed even if polyborodiphenylsiloxane is added as catalyst (Figure 3.). 

The formation ofC—C bonds between aromatic rings is an important step in many organic syntheses and can be accomplished by chemical, photochemical, or electrochemical means. As was noted earlier, fundamental considerations of the parameters for a dielectric which must be dealt with in designing a thermally stable, low-dielectric-constant polymer naturally lead one to consider rigid-rod, nonconjugated aromatic polymers containing no lossy functional groups. A structure such as poly(naphthalene) is a likely candidate. 

Biological significance can sometimes arise in rather unexpected ways the thermal properties of chelate polymers of 2,6-diaminopimelic acid (dap 12) and 4,4 -diamino-3,3 -dicarboxybiphenyl (bbdc 13) with Zn11 have been compared241 with those of non-polymeric divalent metal chelates with amino acids. This confirms the expected enhancement of thermal stability when coordination polymerization occurs, these results possibly being relevant to the thermal stability of certain bacterial spores which contain dap. Zn11 complexes of dap are more thermally stable than those of bbdc, possibly because the latter chelate cannot pack as well, due to the intermolecular repulsions of the biphenyl groups. 

Some of the latest work on high refractive index polyphosphazenes makes use of polymers that contain both fluoroalkoxy and di- or tri-chlorophenoxy side groups.261 These amorphous glasses are thermally stable up to 400 °C, show a large variation of refractive index with temperature, and refractive index values that vary from 1.39-1.56 depending on composition. Thus, they are candidates for uses in thermo-optical switching devices. 

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