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Nanomaterial-based FRs
Published in Asim Kumar Roy Choudhury, Flame Retardants for Textile Materials, 2020
Organoclay is another class of nanofillers used for flame retardant polymer nanocomposites due to its barrier effect. Montmorillonite (MMT) clay constitutes the most commonly studied layered silicate for producing clay-based nanocomposites. MMT reduces the peak heat release rate (PHRR) of polymer nanocomposites by the formation of protective and thermal-insulating layers (Kashiwagi et al., 2004). The concept of synergism between nanofillers was proposed in recent years to achieve better flame retardant performance. Higher enhancement of thermal stability, as compared to binary systems, as well as increased residual char, and lower peak heat release rate (PHRR) in different polymer systems were obtained by using the mixture of nanoclay and MWNT (Hapuarachchi and Peijs, 2010). The mechanism behind this synergism was hypothesized to be the sealing effect of MWNTs between clay platelets, creating a compact protective surface layer (Kashiwagi et al., 2008).
Recent Developments on Antimicrobial Polymer Nanocomposites: Focus on Fibers and Yarns
Published in Mangala Joshi, Nanotechnology in Textiles, 2020
Our research team has been putting in effort for nearly a decade to produce functional nanocomposite filaments from fiber-forming polymers like PE, PP, PET, PUs, and polyamides, and understanding their structure-property relationship and evolution of the microstructure [206–214, 216]. Our work on antimicrobial filaments is on the exploration of a variety of inherently antimicrobial NPs on supports such as naturally occurring inorganic clay. A supporting surface of clay is necessary to prevent the agglomeration of high-surface-area NPs and thereby maximize its antimicrobial property. Agglomerated NPs in the polymer structure additionally hamper mechanical properties and induce tackiness. Clay-based polymer nanocomposites occupy a significant place in the classification of polymeric nanocomposites, with the advantages of incorporation of a natural inorganic material embedded in an organic polymer matrix, uplifting the thermal, mechanical, thermos-oxidative, gas barrier, and flammability properties. MMT, a member of the smectite group of clays, characterized by a layered structure and the ability to absorb cationic moieties in the intergallery space, was chosen as a carrier to load NPs and antimicrobial substances. MMT is an aluminosilicate material with a thickness of ~1 nm and the lateral dimension varying from 200 to 300 nm. Finely dispersed rigid particulate MMT in a host polymeric matrix imbibes a reinforcing effect with many additional advantages.
X-Ray Diffraction
Published in Rui Yang, Analytical Methods for Polymer Characterization, 2018
Various lamellar fillers, e.g., montmorillonite (MMT), are widely used in polymer materials. MMT is a layered silicate, with the layer thickness of ~1 nm and interlayer spacing of ~1 nm. Before it is introduced into polymer materials, organic treatment should be performed to enlarge the interlayer spacing and intercalate organics or polymer chains into it, or even to exfoliate the layers in order to obtain nanoplatelets. By dispersing the intercalated or exfoliated MMT particles in a polymer matrix, a nanocomposite is prepared. Whether MMT is intercalated or exfoliated, and the interlayer spacing of MMT can be determined using XRD.
Fabrication and mechanical properties of braided flax fabric polylactic acid bio-composites
Published in The Journal of The Textile Institute, 2025
Sateeshkumar Kanakannavar, Jeyaraj Pitchaimani
Thermo-mechanical properties of the novel manicaria saccifera palm fabric reinforced PLA composites are studied by Porras et al. (2016). Composites are fabricated by compression molding method and are characterised for thermal analysis (TGA), tensile, flexural and izod impact tests. The manicaria saccifera fabric reinforced PLA composite showed lower thermal degradation temperature and improved mechanical properties compared to neat PLA. Ben et al. (2007) prepared kenaf fiber fabric (unidirectional and cross-ply) reinforced PLA composites and performed tensile test. Results revealed that the unidirectional fabric reinforced composites have higher strength compared to neat PLA and cross-ply quasi-isotropic textile composites. Kumar et al. (2010) fabricated the woven flax reinforced and montmorillonite clay (MMT) added PLA bio-composites. From the mechanical properties and water absorption studies it is noticed that the addition of MMT enhanced the modulus and water resistance properties of the composites. Pickering and Efendy (2016) done an experimental investigation on PLA reinforced by discontinuous alkali treated natural fiber (harakeke and hemp) mats and these mats are produced by dynamic sheet former (DSF). The mechanical properties of these natural fiber mat composites are increased compared to virgin PLA.
Study on influencing factors of Pickering emulsion stabilized by modified montmorillonite and fatty alcohol polyoxyethylene ether
Published in Journal of Dispersion Science and Technology, 2022
Qian Chen, Zeyu Yang, Xiumei Tai, Yanyun Bai, Guoyong Wang
Montmorillonite (MMT) is a 1:2 layered aluminosilicate clay mineral composed of a single-layer aluminoxy octahedron and a double-layered siloxane tetrahedron.[25] Montmorillonite (MMT) has good cation exchange and strong adsorption capacity, no pollution, low price and abundant reserves. And MMT is one of the most popular stabilizers for Pickering emulsion. The surface of modified MMT is hydrophilic and hydrophobic because of the presence of a large number of inorganic exchangeable cation between layers that it is common to replace Na+, Ca2+ between MMT layers with long-chain quaternary ammonium salts to improve the hydrophilicity of MMT.[26,27] For example, Zhang et al. hydrophobized MMT via cetyltrimethylammonium bromide (CTAB) and observed that the stable emulsion produced a double phase inversion with the increasing of CTAB concentration, the stability of water-oil emulsion gradually increased, then W/O emulsions were obtained. But the emulsion will invert to O/W again if the concentration of surfactant increases gradually.[28] However, due to the requirements of biodegradability and the cost of large-scale applications, its usages are increasingly restricted.[29] In addition, our group prepared a series of emulsions with different lengths of quaternary ammonium salt modified MMT and found that the emulsion phase separated after 7 days.[30]
Curcumin‐loaded electrospun polycaprolactone/montmorillonite nanocomposite: wound dressing application with anti‐bacterial and low cell toxicity properties
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Ali Sadeghianmaryan, Zahra Yazdanpanah, Younes Afzal Soltani, Hamed Alizadeh Sardroud, Mohammad Hossein Nasirtabrizi, Xiongbiao Chen
The thermal behaviors of PCL and PCL/10% MMT are shown in Figure 3 through their TGA profiles. PCL lost 7 and 13% of its initial weight at temperatures of 39.8 and 58.07 °C, respectively, which is attributed to the loss of water. PCL showed weight loss due to thermal degradation starting at around 325.5 °C, with approximately 23% of its initial weight lost by 397.7 °C. For the electrospun PCL/MMT nanocomposite, a weight loss of roughly 18% by 59.21 °C was observed, and is attributed to the loss of adsorbed and interlayer water in the organo clay; about a 20% weight loss had occurred by 397.9 °C. The degradation temperature (Td) of PCL increased to 338 °C when it was combined with MMT. As such, an improvement in thermal stability was observed and the TGA curve shifted to higher temperatures upon incorporation of organo clay, indicating the efficient dispersion of organo clay into PCL matrix. The reduction in polymer weight loss in the presence of N2 due to the introduction of MMT is consistent with Elias et al. [16], who report nanoclay shifts the thermal stability of electrospun PCL towards higher temperatures. A similar observation was also described by Marras et al. [27], who investigated the role of organically-modified montmorillonite (Cloisite 25 A) on the properties of electrospun PCL/MMT nanocomposites. Homogeneous dispersion of MMT layers within the polymer causes a barrier property that reduces the permeability of combustible gases into the polymeric matrix and enhances the thermal stability as a result [30].