In situ WAXS/SAXS structural evolution study during uniaxial stretching of poly(ethylene therephthalate) nanocomposites in solid state: Poly(ethylene therephthalate)/montmorillonite nanocomposites

Abstract

This work investigates the solid state uniaxial stretching of neat polyethylene therephthalate, PET, and its montmorillonite, MMT, nanocomposites (0.3 wt % of MMT particles with different initial agglomerate sizes) showing intercalated and tactoid morphologies, followed by in situ WAXS and SAXS experiments under an X-ray synchrotron source. The distinct nanocomposite morphologies were assessed by WAXS and transmission electron microscopy. The in situ WAXS experiments during stretching evaluated the evolution of phase's mass fractions and the average level of molecular orientation upon uniaxial deformation, and the in situ SAXS experiments assessed the evolution of craze-like structures and void sizes. Multiscale structure evolution models are proposed and compared for neat PET and its nanocomposites. Main global mechanisms are identical although with distinct evolutions of phase mass fractions. Also craze-like/voids structures evolve with distinct sizes. Intercalated MMT morphology induces an earlier formation of periodical mesophase, a retarded widening of craze-like structures and the smallest void sizes.V C 2012 Wiley Periodicals, Inc. J.Appl. Polym. Sci. 128: 2884-2895, 2013

In situ WAXS/SAXS structural evolution study during uniaxial stretching of poly(ethylene terephthalate) nanocomposites in the solid state: Poly(ethylene terephthalate)/titanium dioxide and poly(ethylene terephthalate)/silica nanocomposites

“…The effect of incorporation of TiO 2 and SiO 2 nanoparticles into the PET matrix on the structural evolution when compared with the neat PET is shortened hereafter. The presence of nanofillers leads to higher strain levels during the plastic deformation of the matrix and enhanced its toughness.…”

“…The mass fractions of the individual phases were taken as the ratio of the area for each phase to the total area of the equatorial profile. As the strain increases, the WAXS patterns can exhibit a pair of meridional mesomorphic reflection at about 2θ = 25.8°, indicating conformational regularity, and called PM . At this stage of deformation, the morphologies of the samples were considered to be composed of three phases: (i) amorphous, (ii) mesophase, and (iii) PM, mesophase with conformational periodicity perpendicular to the stretching direction.…”

“…As the strain increases, the WAXS patterns can exhibit a pair of meridional mesomorphic reflection ð103Þ at about 2h 5 25.8 , 29,30 indicating conformational regularity, and called PM. 26,31 At this stage of deformation, the morphologies of the samples were considered to be composed of three phases: (i) amorphous, (ii) mesophase, and (iii) PM, mesophase with conformational periodicity perpendicular to the stretching direction. The area of fitted ð103Þ peak profile was used to determine the mass fraction of the PM.…”

Structural, mechanical, and gas barrier properties of poly(ethylene terephthalate) nanohybrid using nanotalc

“…The streak also results from the fibrils or void elongation which results due to stretching in perpendicular direction. 42 Different mesophases have been reported previously by stretching the polymer. [43][44][45] Lorentz corrected I(q)q 2 versus q plots have been shown in Figure 4(b) where, I(q) is the scattering intensity and q is the scattering vector.…”

Tunable Mechanics in Electrospun Composites via Hierarchical Organization

“…35,36 (Figure 2e). Larger MMT tactoids would have been indicated by a reappearance of the clay spacing peak at ∼1.4 nm.…”