Characterization of Polyamide 6/Multilayer Graphene Nanoplatelet Composite Textile Filaments Obtained Via In Situ Polymerization and Melt Spinning

Studies of the production of fiber-forming polyamide 6 (PA6)/graphene composite material and melt-spun textile fibers are scarce, but research to date reveals that achieving the high dispersion state of graphene is the main challenge to nanocomposite production. Considering the significant progress made in the industrial mass production of graphene nanoplatelets (GnPs), this study explored the feasibility of production of PA6/GnPs composite fibers using the commercially available few-layer GnPs. To this aim, the GnPs were pre-dispersed in molten ε-caprolactam at concentrations equal to 1 and 2 wt %, and incorporated into the PA6 matrix by the in situ water-catalyzed ring-opening polymerization of ε-caprolactam, which was followed by melt spinning. The results showed that the incorporated GnPs did not markedly influence the melting temperature of PA6 but affected the crystallization temperature, fiber bulk structure, crystallinity, and mechanical properties. Furthermore, GnPs increased the PA6 complex viscosity, which resulted in the need to adjust the parameters of melt spinning to enable continuous filament production. Although the incorporation of GnPs did not provide a reinforcing effect of PA6 fibers and reduced fiber tensile properties, the thermal stability of the PA6 fiber increased. The increased melt viscosity and graphene anti-dripping properties postponed melt dripping in the vertical flame spread test, which consequently prolonged burning within the samples.

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Effect of Different Flame-Retardant Bridged DOPO Derivatives on Properties of in Situ Produced Fiber-Forming Polyamide 6

Polymers ◽

10.3390/polym12030657 ◽

2020 ◽

Vol 12 (3) ◽

pp. 657 ◽

Cited By ~ 6

Author(s):

Jelena Vasiljević ◽

Marija Čolović ◽

Nataša Čelan Korošin ◽

Matic Šobak ◽

Žiga Štirn ◽

...

Keyword(s):

Flame Retardant ◽

Melt Spinning ◽

Research Work ◽

Polyamide 6 ◽

Fibrous Materials ◽

Comprehensive Properties ◽

Novel Approach ◽

Dispersion State ◽

Spinning Process

The production of sustainable and effective flame retardant (FR) polyamide 6 (PA6) fibrous materials requires the establishment of a novel approach for the production of polyamide 6/FR nanodispersed systems. This research work explores the influence of three different flame-retardant bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivatives on the comprehensive properties of in situ produced PA6/FR systems. To this end, in situ water-catalyzed ring-opening polymerization of ε-caprolactam was conducted in the presence of three different bridged DOPO derivatives, e.g., one P−N bond phosphonamidate derivative and two P−C bond phosphinate derivatives. The selected bridged DOPO derivatives mainly act in the gas phase at the temperatures that relatively match the PA6 pyrolysis specifics. The effects of the FRs on the dispersion state, morphological, molecular, structural, melt-rheological, and thermal properties of the in situ synthesized PA6 were evaluated. The specific advantage of this approach is one-step production of PA6 with uniformly distributed nanodispersed FR, which was obtained in the case of all three applied FRs. However, the applied FRs differently interacted with monomer and polymer during the polymerization, which was reflected in the length of PA6 chains, crystalline structure, and melt-rheological properties. The applied FRs provided a comparable effect on the thermal stability of PA6 and stabilization of the PA6/FR systems above 450 °C in the oxygen-assisted pyrolysis. However, only with the specifically designed FR molecule were the comprehensive properties of the fiber-forming PA6 satisfied for the continuous conduction of the melt-spinning process.

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Preparation and characterizations of flame retardant melamine cyanurate/polyamide 6 composite fibers via in situ polymerization

Textile Research Journal ◽

10.1177/0040517516632478 ◽

2016 ◽

Vol 87 (5) ◽

pp. 561-569 ◽

Cited By ~ 20

Author(s):

Yuanyuan Li ◽

Yunzhi Lin ◽

Kai Sha ◽

Ru Xiao

Keyword(s):

Flame Retardant ◽

Flame Retardancy ◽

Melt Spinning ◽

Cyanuric Acid ◽

In Situ Polymerization ◽

Polyamide 6 ◽

Composite Fibers ◽

Limiting Oxygen Index ◽

Melamine Cyanurate

To improve the flame retardancy of polyamide 6 (PA6) fibers, melamine cyanurate (MCA)/PA6 composites were synthesized via in situ polymerization of ɛ-caprolactam in the presence of adipic acid-melamine salt and cyanuric acid-hexane diamine salt. The flame retardant MCA/PA6 composite fibers were prepared by melt spinning. The structure and properties of MCA/PA6 composites and MCA/PA6 composite fibers were studied by Fourier transform infrared spectra, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, tensile tests, vertical burning tests (UL94) and limiting oxygen index (LOI) tests. Experimental results indicated that the MCA/PA6 composites loaded with 8 wt% of additives can achieve UL94 V-0 rating with an LOI value of 29.3%. The tenacity at break of PA6 fiber decreased from 4.85 to 3.11 cN·dtex–1 for MCA/PA6-8 composite fiber. However, the MCA/PA6 composite fibers can effectively suppress the propagation of flame in fabric. This means that the in situ polymerization approach paves the way for the preparation of MCA/PA6 composites that have good spinnability and flame retardancy.

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PA6 and Halloysite Nanotubes Composites with Improved Hydrothermal Ageing Resistance: Role of Filler Physicochemical Properties, Functionalization and Dispersion Technique

Polymers ◽

10.3390/polym12010211 ◽

2020 ◽

Vol 12 (1) ◽

pp. 211 ◽

Cited By ~ 6

Author(s):

Valentina Sabatini ◽

Tommaso Taroni ◽

Riccardo Rampazzo ◽

Marco Bompieri ◽

Daniela Maggioni ◽

...

Keyword(s):

Physicochemical Properties ◽

Polymer Matrix ◽

In Situ Polymerization ◽

Cost Effective ◽

Polyamide 6 ◽

Halloysite Nanotubes ◽

Amide Bonds ◽

Molecular Weights ◽

Dispersion Technique

Polyamide 6 (PA6) suffers from fast degradation in humid conditions due to hydrolysis of amide bonds, which limits its durability. The addition of nanotubular fillers represents a viable strategy for overcoming this issue, although the additive/polymer interface at high filler content can become privileged site for moisture accumulation. As a cost-effective and versatile material, halloysite nanotubes (HNT) were investigated to prepare PA6 nanocomposites with very low loadings (1–45% w/w). The roles of the physicochemical properties of two differently sourced HNT, of filler functionalization with (3-aminopropyl)triethoxysilane and of dispersion techniques (in situ polymerization vs. melt blending) were investigated. The aspect ratio (5 vs. 15) and surface charge (−31 vs. −59 mV) of the two HNT proved crucial in determining their distribution within the polymer matrix. In situ polymerization of functionalized HNT leads to enclosed and well-penetrated filler within the polymer matrix. PA6 nanocomposites crystal growth and nucleation type were studied according to Avrami theory, as well as the formation of different crystalline structures (α and γ forms). After 1680 h of ageing, functionalized HNT reduced the diffusion of water into polymer, lowering water uptake after 600 h up to 90%, increasing the materials durability also regarding molecular weights and rheological behavior.

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The Effect of the Parameters of T-RTM on the Properties of Polyamide 6 Prepared by in Situ Polymerization

Materials ◽

10.3390/ma13010004 ◽

2019 ◽

Vol 13 (1) ◽

pp. 4 ◽

Cited By ~ 1

Author(s):

Orsolya Viktória Semperger ◽

András Suplicz

Keyword(s):

Mechanical Properties ◽

Automotive Industry ◽

Cycle Time ◽

In Situ Polymerization ◽

Rapid Development ◽

Polyamide 6 ◽

Raw Material ◽

Short Cycle ◽

Short Cycle Time

With the rapid development of the automotive industry, there is also a significant need to improve the raw materials used. Therefore, the demand is increasing for polymer composites with a focus on mass reduction and recyclability. Thermoplastic polymers are preferred because of their recyclability. As the automotive industry requires mass production, they require a thermoplastic raw material that can impregnate the reinforcement in a short cycle time. The most suitable monomer for this purpose is caprolactam. It can be most efficiently processed with T-RTM (thermoplastic resin transfer molding) technology, during which polyamide 6 is produced from the low-viscosity monomer by anionic ring-opening (in situ) polymerization in a tempered mold with a sufficiently short cycle time. Manufacturing parameters, such as polymerization time and mold temperature, highly influence the morphological and mechanical properties of the product. In this paper, the properties of polyamide 6 produced by T-RTM are analyzed as a function of the production parameters. We determine the crystallinity and the residual monomer content of the samples and their effect on mechanical properties.

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Features of forming the structure and properties of polyamide-6 via in situ polymerization with oxidized graphite

Journal of Polymer Research ◽

10.1007/s10965-020-02248-5 ◽

2020 ◽

Vol 27 (9) ◽

Author(s):

Dmitriy Leonov ◽

Tatiana Ustinova ◽

Natalia Levkina ◽

Anton Mostovoy ◽

Marina Lopukhova

Keyword(s):

In Situ Polymerization ◽

Polyamide 6 ◽

Structure And Properties ◽

Oxidized Graphite

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In situ Polymerization of Polyamide 6/Boron Nitride Composites to Enhance Thermal Conductivity and Mechanical Properties via Boron Nitride Covalently Grafted Polyamide 6

Polymer Engineering & Science ◽

10.1002/pen.25329 ◽

2020 ◽

Vol 60 (4) ◽

pp. 710-716 ◽

Cited By ~ 2

Author(s):

Hui Fang ◽

Denghui Li ◽

Fangjuan Wu ◽

Xiangfang Peng ◽

Anlin Chen ◽

...

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Boron Nitride ◽

In Situ Polymerization ◽

Polyamide 6

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Study of the Proper Sintering Conditions of Anionically-Polymerized Polyamide 6 Matrices for the Fabrication of Greencomposites

Materials Science Forum ◽

10.4028/www.scientific.net/msf.713.121 ◽

2012 ◽

Vol 713 ◽

pp. 121-126

Author(s):

A. Alfonso ◽

J. Andrés ◽

J.A. García

Keyword(s):

Material Characterization ◽

Mechanical Performance ◽

In Situ Polymerization ◽

Research Work ◽

Polyamide 6 ◽

Liquid Composite Molding ◽

Thermoplastic Matrix ◽

Composite Molding ◽

Long Fiber Thermoplastic

The present research work assesses the manufacture of long fiber thermoplastic matrix composite materials (GreenComposites). Thermoplastic matrices are too viscous to be injected into the conventional LCM (Liquid Composite Molding) molds, and then epoxy, polyester or vinylester resins are used. Nevertheless, the groundbreaking anionic polymerization of caprolactam allows such a synthesis of a thermoplastic APA6 matrix inside the mold. This matrix is sintered from the starting monomers, and presents high mechanical performance and recyclability. In order to do the reactive injection in a LCM mold, it is necessary to control the polymerization mechanism of such a thermoplastic matrix. This paper puts special emphasis on detecting and solving all problems which arose during synthesis. For instance, moisture values were assessed for all starting reactants, since humidity keeps polymerization from occurring. It is thought that once the synthesis and the resulting material characterization are well controlled, the manufacture of GreenComposites through in situ polymerization, as well as addition of state-of-the-art fabrics such as basalt, can proceed successfully.

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