Ring poly

Other, rigid-rod monomers can be incorporated into PET, to increase chain stiffness, and therefore the Tg (Figure 6.5). A prime example of such a rigid copolyester is a multi-ring poly(ethylene terephthalate-imide) [43], As was the case with the polyesteramides of Gaymans, the imide-containing diol monomer, A,A-bis[p-(2-hydroxyethoxycarbonyl)phenyl]-biphenyl-3,3,4,4-tetracarboxy-diimide, was preformed prior to polycondensation, where this monomer is free... 

A related approach has been used for the synthesis of poly(thiaacene)s, which are novel helical aromatic polymers comprised of fused benzothiophene rings, poly(thiaheterohelicene) <20050L755>. 

Rings Poly(dimethylsiloxane) Similar to human vaginal rings Not commercially available abandoned because of poor retention properties... 

The microstructure and the properties depend on the cis/trans ratio of the ring bonding and on the stereochemistry between the rings. Poly(methylene-l,3-cyclopentane) obtained by cyclopolymerization of 1,5-hexadiene shows four different structures from which the tram isotactic structure is predominant, when using simple biscyclopentadienyl compounds. Higher substituted (pen-tamethyl) zirconocenes yield mainly as-connected polymers which are highly crystalline and have melting points up to 190 °C. 

Poly[ i]catenanes having the structure depicted in Fig. If are significantly more easily prepared than [njpolycatenanes relatively few examples are nevertheless known. Illustrated in Fig. 8 is the formation of a poly-[2]catenane from a precursor 25 containing two covalently linked ringed poly ethers. When treated with the... 

An alternative to the threading, shpping and clipping routes dealt with so far, is to join two half-threads in the presence of a potential ring. This synthetic method was successfully apphed to the preparation of singly- and doubly-ringed poly-acetylenic threads (LlllO from Lilli Eq. 4.70). Diedrich s cyclophane (L1112) conferred water solubility on these rotaxanes [223]. 

Quantity Units 1,4-Dithiol Benzene 3-Ring Poly phenylene Wire Polyphenylene RTD (5 rings) Carbon Nano tube Copper Wire... 

Another example of chlorine-enhanced sensitivity is with the use of pendant chloromethyl groups on aromatic rings. Poly(chloromethylstyrene) and chlorinated poly(p-methylstyrene) have been studied as e-beam resists and have been found to have good sensitivity to 4.36 A radiation. 

Schappacher M, Deffieux A (2011) Reversible switching between linear and ring poly(EO)s bearing iron tetraphenylporphyrin ends triggered by solvent, pH, or redox stimuli. Macro-molecules 44 4503-4510... 

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