Facile preparation and characterization of soluble aramid
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education,
Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing
Beijing National Laboratory for Molecular Sciences, Laboratory of Polymer Physics and Chemistry, Institute of Chemistry,
Chinese Academy of Sciences, Beijing 100871, China
Correspondence to: J. Xu (E -mail: email@example.com or firstname.lastname@example.org or email@example.com)
It remains a problem to prepare cost-effective aramid with good solubility via a simple method since the commercializa-
tion 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
-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
’s) in air higher than
460 8C and glass transition temperatures (T
’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 commer-
2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46341.
functionalization of polymers; polyamides; structure–property relationships
Received 18 November 2017; accepted 3 February 2018
Wholly aromatic polyamide (aramid) is one of the three high
value-added high-performance materials of the 21st century,
including ultra-high-molecular-weight polyethylene, aramid,
and carbon fiber. Aramid possesses remarkable thermal stability,
outstanding mechanical strength, great chemical resistance, and
It is considered the most promising
replacement of metals or ceramics in many areas, such as mili-
tary, aircraft, spacecraft, microelectronics, and automotive
However, due to the high cost of production, only
a few kinds of them have been commercialized. Among them,
all-para-phenylene oriented aramid, poly(p-phenylene terphtha-
lamide) (PPTA, Kevlar, DuPont, Wilmington, State of Dela-
ware), and all-meta-phenylene oriented aramid, poly(m-
phenylene isophthalamide) (PMIA, Nomex, DuPont, Wilming-
ton, State of Delaware), are best known commercial aramids
with superior properties and have applications in bullet-proof
clothing, coatings, fillers, composites, and others.
However, the interactions of the hydrogen-bonding and pAp
stacking between the polymer chain of these aramids are extremely
strong, resulting in insolubility in almost all organic solvents.
The solution processing of the polymers is difficult. PMIA is only
soluble in a few organic solvents containing inorganic salts. PPTA
is only soluble in solvents such as concentrated H
is highly corrosive and not environmentally friendly.
Moreover, polymers often degrade in H
. These drawbacks
limit the manufacturing of aramids, and the cost is high.
Improving the solubility of aramids is very important.
Considering the excellent comprehensive properties of aramids,
on the one hand, a lot of researches have been focused on
improving the solubility and processability of aramids.
eral approaches were applied to increase the solubility, including
introduction of flexible functionalities
such as ether, sulfone,
and aliphatic linkages, introduction of twisted and non-coplanar
structures, bulky pendants, unsymmetrical, and alicyclic struc-
tures to the backbone,
and N-alkylation of the backbone.
Additional Supporting Information may be found in the online version of this article.
2018 Wiley Periodicals, Inc.
J. APPL. POLYM. SCI. 2018, DOI: 10.1002/APP.46341
46341 (1 of 10)