Molecular composites via <i>in situ</i> polymerization: Poly(phenylene terephthalamide)–nylon 3

Abstract

Abstract All‐polyamide molecular level composites composed of rigid rod and flexible coil polymers were prepared using an in situ polymerization process in which the anion of the rigid rod poly‐(phenylene terephthalamide) (PPTA) was used as the initiator for the anionic polymerization of acrvlamide to form the nylon 3 matrix. The rigid aramid component then serves as the reinforcing agent. This polymerization resulted in both graft and homo‐nylon 3 formation. Composite films prepared using in situ processing showed greatly improved strength and modulus over unmodified nylon 3 with no loss of flexibility. The composites showed aggregation and phase separation of PPTA fibrils at PPTA weight fractions of &gt; 30% as indicated by wide angle X‐ray scattering and electron microscopic analysis. The structure of the PPTA formed is that produced from swelled liquid crystalline solutions, indicating that the in situ process involves polymerization in the liquid crystalline state.