Improved mechanical properties of poly(ethylene terephthalate) nanocomposite fibers

Abstract

Improvements in Young's modulus and strength (tenacity) of poly(ethylene terephthalate) (PET) fibers were obtained by drawing unoriented nanocomposite filaments containing low concentrations (<3 wt%) of various organically modified montmorillonites (MMTs) in a second step at temperatures above the glass transition. Prior to melt spinning, solid‐state polymerization was used to rebuild lost molecular weight, due to MMT‐induced degradation, to a level suitable for producing high strength fibers. Greater improvements in mechanical properties occurred when the MMT stacks were intercalated with PET. A nominal 1 wt% loading of dimethyl‐dehydrogenated tallow quaternary ammonium surface modified MMT in drawn PET fiber showed a 28% and 63% increase in Young's modulus and strength, respectively. Relative to an unfilled PET fiber, these results surpassed the upper bound of the rule of mixtures estimate and suggested that both the type of surface modification and concentration of MMT affect the degree of PET orientation and crystallinity. Furthermore, drawability above Tg and elongation at break increased upon the addition of organically modified MMT to unoriented PET fibers, which was a key distinction of this work from others examining similar systems. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers

Interrelationship of thermal and mechanical properties of poly(ethylene terephthalate)/poly(ethylene 2,6-naphthalate)/graphene nanocomposites

“…In other words, a high modulus of graphene and its prevention effect against mobility of chains cause the response of samples to turn brittle . Furthermore, the following reasons were reported as explanation of this observation : Increments in stiffness of the sample as a result of the presence of nanoparticles and the formation of some microvoids around the nanoparticles during the tensile experiment act as stress concentration points and eventually result in a brittle response during tensile testing. The localization of layered plates of graphene between polymer chains reduces entanglements and decreases the strength of sample. …”

Physical and dyeing properties of poly(ethylene terephthalate)/montmorillonite nanocomposite filament yarns

“…However, most investigations on PET/clay nanocomposites mainly concern their engineering plastic applications. There have been numerous studies related to the PET/montmorillonite nanocomposites dealing with their synthesis, processing conditions, nanoscale morphology, mechanical and thermal properties, and their relations [1, 17–27]. Nevertheless, physical and dyeing properties of PET/clay nanocomposites in filament yarn form have been studied only by Teli and Kale [28] so far, although dyeability of PET and its compatibility with clay are of great importance in fiber production and application.…”

Preparation, characterization, and applications of poly(ethylene terephthalate) nanocomposites

“…Melt-based synthesis methods may have certain limitations, pertaining to degradation of polymer and nanoclay modifiers at high processing temperatures (Chen et al, 2012). Methods such as solid-state polymerization can potentially enable compensation for polymer degradation occurring during the melt-mixing process (Litchfield et al, 2010). Other approaches include using a clay-supported catalyst or a chain extender (Choi et al, 2006;Xu et al, 2009).…”