Poly defect groups

In Figure 8-1 we show the chemical structure of m-LPPP. The increase in conjugation and the reduction of geometrical defects was the main motivation to incorporate a poly(/ -phenylene)(PPP) backbone into a ladder polymer structure [21]. Due to the side groups attached to the PPP main chain excellent solubility in nonpolar solvents is achieved. This is the prerequisite for producing polymer films of high optical quality. A detailed presentation of the synthesis, sample preparation,... 

Krupers et al. [43] observed that structure defects introduced by non-ionic hydroxyethyl methacrylate (HEMA) into poly(acrylic acid) decreased the degree of complexation of carboxylic acid groups with PEO and lowered the effldent packing of PEO on the acrylic acid copolymer chains. When the AA/HEM A ratio of the copolymer exceeded 1 1, no complex formation was detectable. 

The fact that the rigidity of poly(amide hydrazide) molecules is lower than that of PPPhTPhA can also be explained by the presence of defective amide groups (with cis-structure) in the former (Table 9). 

Interactions between macromolecules can occur in formulations, for example when preparations are mixed. They can be put to good advantage in the synthesis of novel compounds. Polyethyleneimine and poly(acrylic acid) form a polyelectrolyte complex with saltlike bonds as shown in (V). If the complex is heated as a film, interchain amide bonds are formed between the groups which formed electrostatic links. The nonionised -COOH and -NH groups in the chain are the points of structural defects in the film. 

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