Poly p-phenylenebenzobisthiazole

This section concentrates upon the development of materials based on aromatic polyamides, particularly poly(p-phenylene terephthalamide) (PPT) (II) u,7 l) and on poly(p-phenylenebenzobisthiazole) (PBT) (IV)75). These material, are primarily intended to satisfy the demands of industry for lightweight, high-performance hiaterials suitable for reinforcement purposes, especially in composites. The polymers have therefore been fabricated mainly into fibrous products. 

Poly(p-phenylenebenzobisthiazole) with poly(2,5,(6 )-benzimidazole) MC of oriented macromolecules films and fibers had high modulus and strength Hwang a/., 1983... 

In this next sections an attempt will be made to collect on the examples of poly(p-phenylenebenzobisthiazole), poly-p-oxybenzoate and poly(p-ptenylene ter-ephthalamide) the sparse evidence suggesting that dynamic disorder may sometimes also be of importance for the understanding of stiff molecules. 

On the basis of these principles we have studied extensively the orientability of a rigid rod system (PBT, poly-p-phenylenebenzobisthiazole) in terms of rotational difiusion coefiicients and the mutual interference ( entanglement ) of the rods as the concentration is increased 18, 19). Similar studies are being conducted here also on biomolecules forming rigid or wormlike systems such as collagen (where denaturation can be followed) and xanthan gum. 

The efficacy of this supramolecular engineering strategy was first demonstrated for heterocyclic rod-coil copolymers, with poly(p-phenylenebenzobisthiazole) (PBZT) and derivatives used as the rod-like segments(7Q). The wavelength of absorption and emission of rod-coil copolymers... 

Hot (100 C) 97% sulfuric acid is a good solvent for poly(p-phenylenebenzobisthiazole) (PBT) (Figure 13.5). A drastical drop in the solvent power is achieved by a decrease in temperature which causes thermoreversible gelation of the system [47]. The formation of a porous structure from a uniform, homogeneous, isotropic solution has been observed. Indications were found that the gel melting temperature increases with concentration and molecular weight of PBT. 

Very few investigators have reported on strain scaling with first normal stress difference N (t, y) for lyotropic LCPs after reversal in flow direction. Chow et al. (1992) reported variations of N t,y) with yt for lyotropic solutions of poly(p-phenylenebenzobisthiazole) (PBZT) after reversal in flow direction, indicating that for this system (t, y) does not follow strain scaling after flow reversal. Hongladarom... 

The ordered polymer programme of the US Air Force has produced some very exciting developments in the area of strong and stiff polymers with good high temperature resistance. " " The two most interesting polymers are poly(p-phenylenebenzobisthiazole), (PBT, 2) and poly(p-phenylenebenzobisoxazole), (PBO, 3). 

Rigid polymers such as polyphenyl, a-helical polypeptides, or poly(p-phenylenebenzobisthiazole) (PBT). 

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