On the crystal and molecular structure of poly‐(p‐phenylene terephthalamide)

N,N'-(p-Phenylene)dibenzamide (PPDB)

“…The angle between the planes of the amide group and phenyl ring B is 35.9 ° , which is significantly different from the corresponding value, 17.6 ° , found in acetanilide (Brown, 1966). It should be noted that the values found are in good agreement with the angles estimated by Northolt & Van Aartsen (1973) for the polymer poly(pphenyleneterephthalamide). As in benzamide and acetanilide, these twist angles are supposed to be due to steric hindrance between H(3) and H(6), and H(8) and O.…”

“…Aromatic and mixed aliphatic-aromatic polyamides form a class of polymers having thermal and mechanical properties which are quite different from those of aliphatic polyamides. These exceptional properties are thought to be due to the fact that aromatic polyamides have a very high degree of crystailinity (Northolt & Van Aartsen, 1973). In order to obtain more insight into the structures of the crystalline phase of the polyamides a number of model compounds have been synthesized (Gaymans & Harkema, 1977).…”

Structural Investigations of Fibers and Films of Poly(p-phenylene benzobisthiazole). Volume 1

“…Northolt [76,77,78] and Tadokoro [82] have reported very similar crystal structures for highly oriented well annealed fibers of PPTA. The basic structure is monoclinic (pseudo-orthorhombic) with al = 0.787 nm, Jb = 0.518 nm, Ic = 1.29 nm and close to 90 degrees [78] and is depicted in Figure 55.…”

Microstructural developments of poly (p-phenylene terephthalamide) fibers during heat treatment process: a review

“…Northolt investigated the fiber structure. He reached the conclusion that the supermolecular structure instead of having a two-phase structure consisting of amorphous and crystalline domains, it-probably-has a paracrystalline structure 34 . The crystal molecular structure of PPTA fibers is monoclinic (pseudo-orthorhombic).…”

“…The layer of the hydrogen-bonded chains and the contents of the cell are shown in Figures 9a Figure 9. The PPTA crystal lattice with pseudo-orthorhombic unit cell 33,34 . and b: (a) the projection of the crystal structure parallel to the a-axis of a layer of hydrogen-bonded chains and (b) is the projection parallel to the c-axis.…”