Synthesis and properties of nylon 6 modified with various aromatic polyamides

Abstract

ABSTRACT:In this study, flexible nylon 6 was reinforced by the following rigid-chain aromatic polyamides: poly( m-phenylene isophthalamide) (PmIA), poly(4,4 -diphenylsulfone terephthalamide) (PSA), poly( p-diphenyloxide terephthalamide) (POA), and poly( p-diphenylmethane terephthalamide) (PMA). Various high-molecular-weight block copolyamides were synthesized by solution polymerization using p-aminophenylacetic acid (p-APA) as a coupling agent. Their thermal properties have shown that the block copolyamides exhibit higher T g and T m and better thermal stability than those of nylon 6, especially PmIA-modified nylon 6. The order of their thermal properties of aromatic modified nylon 6 copolyamides is PmIA ú PMA ú POA ú PSA. Besides, the T g and T m of multiblock copolyamides are higher than those of triblock copolyamides. From the wide-angle X-ray diffraction pattern, it is found that the triblock copolyamides have two diffraction peaks (i.e., 2u Å 20.5 and 24Њ). However, the multiblock has only one at 2u Å 20Њ, indicating a different crystal structure for multiblock copolyamides. This can be further confirmed from scanning electron microscopy. It shows that the triblock copolyamides are a dispersed phase structure, although the multiblock copolyamides exhibit a homogeneous texture rather than an aggregated one. For the mechanical properties, it is found that the multiblock copolyamides have a more significant reinforcing effect than the triblock copolyamides. Also, the order of their physical properties of aromatic modified nylon 6 copolyamides, such as tensile strength, is PmIA ú PMA ú POA ú PSA; but for the elongation, the order is PSA ú POA ú PMA ú PmIA.

Synthesis of Modified Polycaprolactams Obtained from Renewable Resources

“…Burillo and co‐workers described another modification method using acrylic acid and 4‐vinyl pyridine in γ‐ray grafting onto nylon films . Furthermore, Wang and Lin described the reinforcement of nylon using various aromatic polyamides to obtain copolyamides with higher melting points, higher glass transition temperatures as well as better thermal stability compared to unmodified nylon . Different aromatic copolyamides were obtained using a nylon prepolymer, an aromatic prepolymer and a coupling agent.…”

Synthesis and characterization of some polyamides incorporating modified isophthalic acid units

“…The cinnamoyl moieties were introduced through amido and ester bonds by reacting 5‐aminoisophthalic acid and 5‐hydroxyisophthalic acid, respectively, with the cinnamoyl chloride in N ‐methyl‐2‐pyrrolidone, in the presence of triethylamine. N ‐methyl‐2‐pyrrolidone was preferred as a solvent for these syntheses instead of dimethylacetamide which is reactive towards acid chloride 10…”

Synthesis of nylon 6,6 copolymers with aromatic polyamide structure

“…Both IPC)and p ‐aminophenylacetic acid ( p ‐APA) were purchased from the Merck Co. (Darmstadt, Germany) and used as received. The homopolymers of PMA, POA, and PSA were synthesized in our laboratory as described previously 7, 8…”