N‐substituted poly(p‐phenylene terephthalamide)

Abstract

N‐substituted poly(p‐phenylene terephthalamide)s (PPTA), such as N‐alkylated, N‐aralkylated, and N‐carboxymethylated poly(p‐phenylene terephthalamide), were synthesized from PPTA and the corresponding halides by the polymer reaction via the metalation reaction in a solution of sodium methylsulfinylcarbanion in dimethyl sulfoxide at low temperature. The introduction of various substitutional groups into the amide groups of PPTA increased their solubilities, but decreased their thermal stabilities compared with PPTA. The effects of various substitutional groups on the thermal properties and the solubilities are discussed. Liquid crystal formation was noticed for PPTA substituted with bulky groups such as 9‐anthrylmethyl group.

Direct condensation polymerization of N-alkylated p-aminobenzoic acid and packing of rigid-rod main chains with flexible side chains

“…From our experimental findings, it is found that the PABA 0 Table 3 Thermal properties and the crystallinity of polymers -412 444 412 450 --PABA 1 197 --394 425 408 432 --PABA 3 136 227 319 404 421 426 Carbon numbers of alkyl side chain in PABAn From the results of analysis for the reciprocal lattice to diffraction peak and previously reported crystal system of similar polymers, it is found that PABA 1 are packed into a monoclinic lattice with order parameters of a¼g¼901, b¼67.51, a¼7.7 Å , b¼5.7 Å and c¼10.8 Å (Figure 5b). The reported crystal systems of similar polymers in literature, such as poly(p-phenylene terephthalamide) 30 and poly-(p-benzamide), 32 are monoclinic (a¼7.8 Å , b¼5.19 Å , c¼12.9 Å , g¼90 Å ) and orthorhombic (a¼7.71 Å , b¼5.14 Å , c¼12.8 Å ) systems, respectively. In contrast, PABA n polymers with n¼1, 3, 4 or 5 are packed into an orthorhombic lattice with a¼b¼g¼901, a¼7.7 Å , b¼5.6 Å and c¼13.0 Å , because all WAXD peaks of these polyamides can be located on the reciprocal lattice of an orthorhombic system (Figure 5b).…”

“…This is a general characteristic of comb polymers. 30 Figure 3 shows the second heating DSC curves of PABA n . PABA 0 shows no transition or endothermic peak of melting, whereas PABA 1 shows a glass transition temperature (T g ) at 197 1C.…”

“…As the first example, Kevlar, poly(p-phenylene terephthalamide), was functionalized with linear hydrocarbons of 3, 4, 7, 12 and 18 carbon atoms through metalation of poly(p-phenylene terephthalamide) using sodium hydride (degree of substitution (DS) was 86-99%, inherent viscosity (Z inh ) 0.06-0.14), and the packing mode was investigated for the resulting comb polymers, which were all amorphous except for the polymer with C 18 H 37 side chains. 30 Poly (3-n-alkyl-4-oxybenzoate)s (PAOBA)s with alkyl side chains varying from 1 to 18 carbon atoms were prepared and their phase properties fully investigated. 31 The structure and thermal transition from crystalline to mesophase of PAOBA with short alkyl chains, such as propyl groups, was controlled by the rigid-rod main chain, whereas those of PAOBA having longer alkyl chains were controlled by the nature of side chains.…”

Polymer composites of rigid and flexible molecules

“…A new type of proton substitution reaction of CONH in PPTA molecule was found by the author (Ref. 2). Unusual effectiveness of reinforcement was found for the system of the surfacemodified PPTA filament/sodium ion-type ionomer.…”

Solid-state Structure and Formation of Organized Molecular Films for Poly-(<i>N</i>-alkylated benzamides) Containing Various Chain Lengths

“…As the first example, Kevlar, poly(p-phenylene terephthalamide), was functionalized with linear hydrocarbons of 3, 4, 7, 12 and 18 carbon atoms through metalation of poly(p-phenylene terephthalamide) using sodium hydride (degree of substitution (DS) was 86-99%, inherent viscosity (Zinh) 0.06-0.14), and the packing mode was investigated for the resulting comb polymers, which were all amorphous except for the polymer with C 18 H 37 side chains. 8 Poly (3-n-alkyl-4-oxybenzoate)s (PAOBA)s with alkyl side chains varying from 1 to 18 carbon atoms were prepared and their phase properties were fully investigated. 9 The structure and thermal transition from crystalline to mesophase of PAOBA with short alkyl chains, such as propyl groups, was controlled by the rigid-rod main chain, whereas those of PAOBA having longer alkyl chains were controlled by the nature of side chains.…”