Facile preparation and characterization of soluble aramid

Abstract

It remains a problem to prepare cost-effective aramid with good solubility via a simple method since the commercialization of aromatic polyamides such as Kevlar and Nomex by DuPont in 1960s. Herein, we report the facile preparation and properties of an aromatic polyamide copolymerized by 2,6-naphthalene dichloride (26N-COCl), 4,4 0 -oxydianiline, and m-phenylenediamine. The synthetic route is very facile and cost-effective. The modified aramids possess excellent comprehensive properties. The polymers are soluble in some organics. Their thermal stabilities are excellent, with 5% weight loss temperatures (T d,5% 's) in air higher than 460 8C and glass transition temperatures (T g 's) higher than 280 8C. These polymers are easily processed into films, fibers, and tubes. The products exhibit high strength. For example, the films have excellent mechanical strength, with a tensile strength up to 139 MPa, a tensile modulus up to 3.45 GPa, and an elongation of 11%. The films are also transparent and fluorescent. The overall properties are better than those of the commercial Nomex. The facilely prepared aramids with good solubility are very promising for commercial use.

New polyamides based on diacid with decanediamide and methylene groups and aromatic diamines

“…The solubility of the polymer depends on the morphology/packing pattern/rigidity of the polymer backbone. The solubility is closely related to the structure of the polymer chain; the higher the rigidity and regularity, the poorer the solubility for polyamide 8 . All these polyamides showed good solubility in N‐methyl‐2‐pyrrolidone, N, N‐dimethylacetamide, N, N‐dimethylformamide, dimethyl sulfoxide, m‐cresol, and pyridine.…”

“…The solubility is closely related to the structure of the polymer chain; the higher the rigidity and regularity, the poorer the solubility for polyamide. 8 All these polyamides showed good solubility in N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, m-cresol, and pyridine. Good solubility of these polyamides may be due to the incorporation of the preformed aliphatic C 8 moiety and methylene linkages in the polyamide backbone; which increased the chain flexibility, reduced the chainchain interactions, and prevented the close chain packing.…”

“…3 Hence worldwide research efforts are directed to improve the solubility and hence the processability of aromatic polyamides, without significantly lowering their other desired properties. [4][5][6][7][8] Copolyamides from 2, 6-naphthalene diacid with a mixture of two aromatic diamines containing ether linkage and meta-catenation moiety produced aramids which were soluble in solvents namely NMP and DMSO. Solubility of aromatic polyamides was enhanced by introducing cardo [9][10][11][12][13] and bulky pendant units [14][15][16][17][18][19] such as dibenzobarrelene/ crown ethers and acyclic ethylene oxide in the polyamide backbone.…”

“…However, high melting or glass transition temperature and poor solubility in common organic solvents restrict applications of these aromatic polyamides 3 . Hence worldwide research efforts are directed to improve the solubility and hence the processability of aromatic polyamides, without significantly lowering their other desired properties 4–8 . Copolyamides from 2, 6‐naphthalene diacid with a mixture of two aromatic diamines containing ether linkage and meta‐catenation moiety produced aramids which were soluble in solvents namely NMP and DMSO.…”

Progress in the chemistry of functional aramids properties

“…Xu et al reported [111] the facile preparation of aromatic PAs by copolymerizing 2,6-naphthalene dichloride (26 N-COCl), 4,4 0 -oxydianiline, and m-phenylenediamine through acylation, chlorination, and polycondensation (Scheme 30,P30).Thesepolymers wereeasilyprocessed into films, fibers, and tubes and exhibited high strength. The films were transparent and reported 80% transmittance at 500 nm and displayed high fluorescence.…”