Hydrogen bonding is crucial to the processing and properties of polymer materials, and copolymerization provides effective regulation of interchain hydrogen bonding in macromolecules. However, the relationship between intrachain hydrogen bonding, the parity and length of the monomer carbon chains, and the mechanical properties of copolyamides remain insufficiently explored. Polyamide fiber membranes with excellent mechanical properties were prepared by finely tuning the chain length and parity number of the monomers achieved, by using electrospinning processing of polyamide 6, polyamide 12, polyamide 11, copolyamide 6/66 (CoPA 6/66), copolyamide 6/11 (CoPA 6/11), and copolyamide 6/12 (CoPA 6/12). In particular, CoPA 6/11 has a longer carbon chain and an odd-numbered structure, which results in a lower enthalpy of hydrogen bond breaking (enthalpy of fracture, 41.65 kJ/mol) compared with CoPA 6/66 (86.46 kJ/mol) and CoPA 6/12 (66.26 kJ/mol). This makes CoPA 6/11 more susceptible than other materials to interchain hydrogen bond rearrangements during high-speed rotation in the collector in electrospinning processing. Differential scanning calorimetry also corroborated that CoPA 6/11 molecular chains are more prone to shifting from the γ-crystal to the α-crystal form in response to external forces. As a result, CoPA 6/11 showed the greatest increase in tensile strength (51%, 8.47–17.4 MPa) after high-speed rotation. This study presents an easy method for producing high-strength fibers by controlling the rotation speed to modulate hydrogen bonding between polyamide chains. The approach provides a promising pathway for manufacturing high-strength polyamide fibers for applications in the textile industry, the automotive industry, and other fields.
Al RashidAIkramH, andKoçM.Additive manufacturing and mechanical performance of carbon fiber reinforced polyamide-6 composites. Mater Today Proc2022;
62: 6359–6363.
2.
WangTLiXLuoR, et al.
Effects of amide comonomers on polyamide 6 crystallization kinetics. Thermochim Acta2020;
690: 178667.
3.
SongPTrivediAHawkinsN, et al.
Thermomechanical characterisation of polyamide 6 over a wide range of rates and temperatures. Polymer2024;
300: 126907.
4.
CuiLDongYLiuY, et al.
Crystal structure of uniaxially stretched bio-based polyamide 510 films. J Appl Polym Sci2021;
138: e50748.
5.
ZhangYCaiZWangY, et al.
Effect of sequence distribution on the non-isothermal crystallization of copolyamide 4/6. J Mater Sci2022;
57: 17883–17901.
6.
YanYGooneieAYeH, et al.
Morphology and crystallization of biobased polyamide 56 blended with polyethylene terephthalate. Macromol Mater Eng2018;
303: 1800214.
7.
DjukicSBocahutABikardJ, et al.
Mechanical properties of amorphous and semi-crystalline semi-aromatic polyamides. Heliyon2020;
6: e03857.
8.
MilitkýJVenkataramanM, andMishraR.The chemistry, manufacture, and tensile behavior of polyamide fibers. In: BunsellAR (ed.) Handbook of Properties of Textile and Technical Fibres. 2nd ed.Duxford:
Woodhead Publishing, 2018, pp. 367–419.
9.
KunugiTChidaK, andSuzukiA.Preparation of high-modulus nylon 6 fibers by vibrating hot drawing and zone annealing. J Appl Polym Sci1998;
67: 1993–2000.
10.
HarrellTMLeCShenV, et al.
The effect of stretching on polyamide-6: Assessment of crystallinity, mechanical properties, and surface roughness. J Polym Res2024;
31: 198.
11.
AfshariMSikkemaDJLeeK, et al.
High performance fibers based on rigid and flexible polymers. Polym Rev2008;
48: 230–274.
12.
LiuB-WLongJ-WChenL, et al.
Semi-aromatic polyamides containing fluorenyl pendent toward excellent thermal stability, mechanical properties and dielectric performance. Polymer2021;
224: 123757.
13.
TsvetkovVN.Conformation of aromatic polyamide molecules in solutions. Polym Sci USSR1976;
18: 1857–1865.
14.
PanWShengJXiangH, et al. The mechanical property and crystalline structure of novel high-strength polyamide fibers. In: HanY (ed.) Physics and techniques of ceramic and polymeric materials. CMC 2018.
Singapore:
Springer, 2019, pp. 33–46.
15.
VasanthanN.Polyamide fiber formation: Structure, properties and characterization. In: EichhornSJHearleJWSJaffeM, et al. (eds.) Handbook of textile fibre structure: Fundamentals and manufactured polymer fibres.
Cambridge:
Woodhead, 2009, pp. 232–256.
16.
HuangXNakagawaSHoujouH, et al.
Insights into the role of hydrogen bonds on the mechanical properties of polymer networks. Macromolecules2021;
54: 4070–4080.
17.
WanQThompsonBC.Control of properties through hydrogen bonding interactions in conjugated polymers. Adv Sci2024;
11: 2305356.
18.
DengXZhaiWFanC, et al.
Simultaneous enhancement of axial/transverse compressive strength of aramid fibers by the construction of branched multi-hydrogen bonding sites. Compos Sci Technol2024;
257: 110797.
19.
BunnCWGarnerEV, andBraggWL.The crystal structures of two polyamides (‘nylons’). Proc R Soc London, Ser A1947;
189: 39–68.
20.
PengLLiJPengS, et al.
The crystal-form transition behaviours and morphology changes in a polyamide 6 cyclic dimer. R Soc Open Sci2018;
5: 180957.
21.
ArimotoHIshibashiMHiraiM, et al.
Crystal structure of the γ-form of nylon 6. J Polym Sci, Part A: Gen Pap1965;
3: 317–326.
22.
HasaniZYoussefiMBorhaniS, et al.
Structure and properties of nylon-6/amino acid modified nanoclay composite fibers. J Text Inst2019;
110: 1336–1342.
23.
ZhengXLinQJiangP, et al.
Ionic liquids incorporating polyamide 6: Miscibility and physical propertiesPolymers2018;
10: 562.
24.
XuBYiC.Preparation of nano-CuO@BaSO4 under room temperatures and its application in PA6 composites. J Reinf Plast Compos. Epub ahead of print 28 February 2024. DOI: 10.1177/07316844241236871.
25.
DawelbeitAYuM.Tentative confinement of ionic liquids in nylon 6 fibers: A bridge between structural developments and high-performance properties. ACS Omega2021;
6: 3535–3547.
26.
LuoCJStoyanovSDStrideE, et al.
Electrospinning versus fibre production methods: From specifics to technological convergence. Chem Soc Rev2012;
41: 4708–4735.
27.
ZhangLLeungMYBoriskinaS, et al.
Advancing life cycle sustainability of textiles through technological innovations. Nat Sustainability2023;
6: 243–253.
28.
WangZSongMLiX, et al.
Copolymerization-regulated hydrogen bonds: A new routine for high-strength copolyamide 6/66 fibers. Polymers2022;
14: 3517.
29.
LinCZouFFernández-RoncoMP, et al.
Melting behavior and non-isothermal crystallization kinetics of copolyamide 6/12. Polym Cryst2019;
2: e10054.
30.
SkrovanekDJHoweSEPainterPC, et al.
Hydrogen bonding in polymers: Infrared temperature studies of an amorphous polyamide. Macromolecules1985;
18: 1676–1683.
31.
MaYZhouTSuG, et al.
Understanding the crystallization behavior of polyamide 6/polyamide 66 alloys from the perspective of hydrogen bonds: Projection moving-window 2D correlation FTIR spectroscopy and the enthalpy. RSC Adv2016;
6: 87405–87415.
32.
VinkenETerryAEHoffmannS, et al.
Influence of hydrogen bonding on the conformational changes, the Brill transition, and lamellae thickening in (co)polyamides. Macromolecules2006;
39: 2546–2552.
33.
VasanthanN.Crystallinity determination of nylon 66 by density measurement and Fourier transform infrared (FTIR) spectroscopy. J Chem Educ2012;
89: 387–390.
34.
LeeK-HKimK-WPesapaneA, et al.
Polarized FT-IR study of macroscopically oriented electrospun nylon-6 nanofibers. Macromolecules2008;
41: 1494–1498.
35.
WeiMDavisWUrbanB, et al.
Manipulation of nylon-6 crystal structures with its α-cyclodextrin inclusion complex. Macromolecules2002;
35: 8039–8044.
36.
YangTGaoYWangX, et al.
Hydrogen bonding and crystalline structure of bio-based PA56. Polymer2021;
237: 124356.
37.
NodaI.Two-dimensional infrared spectroscopy. J Am Chem Soc1989;
111: 8116–8118.
38.
ParkYNodaIJungYM.Application of two-dimensional correlation spectroscopy (2D-COS) in polymer studies. In: OzakiYSatoH (eds.) Spectroscopic techniques for polymer characterization: Methods, instrumentation, applications.
Weinheim:
Wiley, 2021, pp. 259–296.
39.
LiuXWangYWangZ, et al.
The origin of memory effects in the crystallization of polyamides: Role of hydrogen bonding. Polymer2020;
188: 122117.
40.
BahramiMAbenojarJ, andMartínezMA.Comparative characterization of hot-pressed polyamide 11 and 12: Mechanical, thermal and durability properties. Polymers2021;
13: 3553.
41.
ItoMMizuochiK, andKanamotoT.Effects of crystalline forms on the deformation behaviour of nylon-6. Polymer1998;
39: 4593–4598.
42.
WuYXuYWangD, et al.
FT-IR spectroscopic investigation on the interaction between nylon 66 and lithium salts. J Appl Polym Sci2004;
91: 2869–2875.
43.
JoseMVSteinertBWThomasV, et al.
Morphology and mechanical properties of nylon 6/MWNT nanofibers. Polymer2007;
48: 1096–1104.
44.
KojimaYMatsuokaT, andTakahashiH.Preparation of nylon 66/mesoporous molecular sieve composite under high pressure. J Appl Polym Sci1999;
74: 3254–3258.
