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The barrier property enhancement of polymers is presently a matter of great concern for the manufacturing of food packaging and films with excellency in moisture and gas resistance. The objective of this work was to enhance the barrier performance of Nylon12/kaolin clay nanocomposites against water vapors and oxygen. Kaolin clays of different aspect ratios were utilized for nanocomposites manufacturing. Nanocomposites were prepared in twin screw extruder operating at 160–200°C, with an increment of 10°C, and at 110 rev/min. The loading of clay was varied from 1 to 5 wt%. Scanning electron microscopy and X‐ray diffraction characterizations were used to investigate the morphological properties of nanocomposites. The transmission electron microscopy analysis was used to confirm the dispersion of clays in Nylon12 matrix. Enhancement in barrier performance of nanocomposite was noticed at 5 wt% clay loading. Oxygen barrier of nanocomposites was observed to be more prominent than water vapors owing to the presence of hydrogen bonding in Nylon12 structure which restricted oxygen passage. Experimental barrier values of nanocomposites were also fitted on barrier models namely Nielsen, Cussler model, and Gusev‐Lutsi model. [ABSTRACT FROM AUTHOR]

ABSTRACT Several bisphenol-A benzoxazine (BEN) based nanocomposites incorporated with several polyhedral oligomeric silsesquioxane (POSS), carbon nanotubes (CNTs), and clays, were prepared successfully. The influences of the nanofillers on curing kinetics, network formation, and thermal stability of the BEN were investigated comprehensively. The addition of the nanofillers showed different influence on curing kinetics of BEN. Furthermore, the incorporation of the nanofillers showed good improvement on thermal stability of BEN. An increase of 70 and 336°C at the onset and the half-life decomposition temperature were observed with the addition of 5 wt % 30B clay in nitrogen atmosphere. With the incorporation of 5 wt % POSS, the half-life of decomposition and char yield enhanced by 280°C and 13 wt % in nitrogen atmosphere. For the 4 wt % MWCNT-COOH/BEN nanocomposite, the half-life of decomposition and char yield at 800°C increased by 286°C and 14 wt % in nitrogen atmosphere, respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41903. [ABSTRACT FROM AUTHOR]

ABSTRACT The full exfoliation of inorganic natural clay was engineered in a nonpolar polyethylene following a novel method without the involvement of any chemical modification to the surface of silicate layers. Tensile results showed that the toughening effect was dependent of strain rates, and the toughness of polyethylene was substantially improved by nearly five times with 0.5 wt % natural clay nanosheets at a strain rate of 0.15 s−1. Toughening mechanism was also discussed based on this new exfoliated system. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41314. [ABSTRACT FROM AUTHOR]

ABSTRACT Heat ageing and thermal stability of a silicone rubber (SR) filled with montmorillonite clay (MMT) was investigated. Three types of rubber nanocomposites were prepared with highly exfoliated Cloisite 30B (SR/C30B), intercalated/exfoliated Cloisite Na+ (SR/Na+MMT), and highly intercalated Cloisite 20A (SR/C20A). This study showed that the SR/C30B nanocomposite exhibited excellent heat resistance in comparison to the other two nanocomposites and neat SR as revealed by higher retention strength. The thermal stability of the rubber in air was strongly dependent on the clay morphology and increased in the following order: highly intercalated/exfoliated SR/Na+MMT < highly intercalated SR/C20A < highly exfoliated SR/C30B. The thermogravimetric analyses of the SR/C30B nanocomposite showed a substantial increase in the final residue in comparison with the neat SR. This indicated a major improvement in the thermal stability of the rubber containing the exfoliated clay, which was also supported by the higher activation energy of decomposition measured for the nanocomposite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41061. [ABSTRACT FROM AUTHOR]

Well-dispersed nanocomposite powder with spherical morphology and suitable particle size for processing by laser sintering was successfully produced by coating polyamide 12 (PA12) powder particles with carbon nanotubes (CNTs). Flexural, impact, and tensile test specimens produced by laser sintering the PA12-CNT powder showed no distortion and good definition. The density of the PA12-CNT laser-sintered parts was higher than that of neat PA12, which the authors propose is mainly due to higher laser absorption by the CNT particles. Compared to the laser-sintered PA12 parts, PA12-CNT parts showed enhanced flexural, impact, and tensile properties without sacrificing elongation at break. This enhancement may be attributed to the good dispersion of the CNT in the PA12 matrix and denser laser-sintered parts. Considering the low weight percentage of CNT used (0.1 wt%), it would seem that the method used in this work is a cost efficient and effective way to produce polymer nanocomposite powders for laser sintering, while maintaining the optimum powder morphology for the laser sintering process and enhancing the mechanical properties of the laser-sintered part. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]