Compatibilization of poly (ethylene terephthalate)/ polypropylene blends via nanostructured silica aerogel

The specific surface areas and pore structure of hydrophilic and hydrophobic silica aerogel particles were determined using the Nitrogen adsorption analysis (Micromeritics -model TriStar II Plus) and Brunaure–Emmitt–Teller (BET) and Barrett–Joyner–Halendar (BJH) methods. The WAXS patterns for samples were performed using Asenware AW-DX 300 (XRD instrument). X-ray spectrometer was used Cu K_a radiation with a wavelength of 1.54 Å that operated at voltage 40 kV and current 30 mA. The data were obtained from 10 to 90 (2θ) at scan range of 0.05°∙min^(-1). The crystallite size was calculated using Debye-Scherrer analyze based on the following equation in X'Pert High Score Plus software. Rheometric Mechanical Spectrometer (RMS) instrument with parallel plate geometry, 25 mm plate diameter, and 1 mm gap (Physica MCR 501) was used to performing the dynamic rheological experiments on binary blends samples. The oscillatory tests in the linear viscoelastic region were done at a set frequency of 1 Hz and 0.3% strain. The frequency was swept from 0.1 to 100 rad∙s-1. All the measurements were accomplished at 270℃ under the nitrogen atmosphere. The storage and loss modulus data obtained from small-angle oscillatory shear (SAOS) experiments can be expressed as a function of relaxation time spectrum H(λ). The continuous relaxation time spectrum for the PP/PET/silica aerogel samples, which are extracted by Matlab software. The solid-like rheological behavior of the PP/PET filled samples can be described by five-parameter Fractional Zener Model (FZM). By fitting the dynamic modulus equation to the experimental data using the nonlinear least-square in Matlab software, the fitting parameters were obtained.