No abstract

The exploitation of beidellite clay (BDT), used as a nanofiller in the preparation of poly(butylene succinate) (PBS)/organoclay biodegradable nanocomposites, was investigated. Their thermal and water vapor barrier properties were also studied.

Bionancomposites from bioplastics and nanoclays are of great interest for packaging, agricultural and other large‐volume and niche applications due to their enhanced physical, thermal, mechanical and processing characteristics compared to the parent polymer. In this study, the biodegradable polyester poly(butylene adipate) (PBA) was synthesized by in situ polycondensation catalysed by titanium tetrabutoxide in the presence of the natural Moroccan clay beidellite (BDT). Optimization of the nanoclay exfoliation in the bionanocomposite was achieved by cation exchange of BDT with cetyltrimethylammonium bromide (CTA) and by selecting the most effective among a range of organically modified xCTA‐BDT (x = CTA/BDT equivalent feed ratio). Fourier transform infrared and 1H NMR spectral and size exclusion chromatographic analyses confirmed the effectiveness of the in situ polymerization, yielding structurally regular PBA with narrow molecular weight dispersity and 7750 < Mtrue‾n < 30 360 g mol−1, depending on the organoclay load. X‐ray diffraction and transmission electron microscopy analyses showed best clay dispersion and homogeneous distribution at 2 wt% 3CTA‐BDT. From thermogravimetric analysis and differential scanning calorimetry results the thermal stability of PBA is greatly improved even at 1 wt% 3CTA‐BDT, its glass transition temperature is nearly unaffected while crystallinity is increased by the organoclay nucleating action. These results, along with a bionanocomposite hydrophilicity only moderately higher than that of PBA, make this preparation approach particularly promising. © 2017 Society of Chemical Industry

No abstract

Novel fluorinated coating containing well-dispersed silicate nanolayers is successfully produced via in-situ free radical polymerization of 2,2,2-trifluoroethyl methacrylate in the presence of vinylbenzyl-functionalized montmorillonite with different loading. The organic modification of sodium montmorillonite is achieved through an ion exchange reaction with triphenylvinylbenzylphosphonium chloride as surfactant prepared before use by reaction with vinylbenyl chloride and phosphine. The following in-situ polymerization in the presence of organomodified clay leads to fluorinated nanocomposites with of partially exfoliated and intercalated morphologies, as determined via XRD and TEM analysis. The nanoscale dispersion of clay layers is also evidenced by thermal analysis; a moderate decrease of the glass transition temperature about 2-8 8C compared to their virgin PMATRIF and an improvement of their thermal stability as evidenced by TGA. The wettability of the nanocomposite films is also studied by contact angle measurements with water. The incorporation of organomodified clays not only increases the hydrophobicity of the fluorinated polymers but also improves the surface properties of obtained nanocomposites. Compared the virgin homopolymer, the mechanical properties of the nanocomposites are reduced by addition of organomodifed clay at temperature from 30 to 60 8C, whereas this trend is gradually decreased at higher temperature.

No abstract

In this work, the dielectric properties of nanocomposites based on poly(2,2,2‐trifluoroethyl methacrylate) copolymer (PMATRIF) and vinylbenzyl‐functionalized montmorillonite (MMT) nanoparticles prepared via in situ free radical polymerization were studied. The effect of different loadings of (MMT) filler (in weight ratios of 1, 3, and 5%) on the molecular dynamics and polarization of PMATRIF was investigated using broadband dielectric spectroscopy from 10−1 to 106 Hz and at temperatures between 20 and 170°C. For PMATRIF matrix, the real part ε′ and the imaginary part ε″ of the dielectric permittivity curves revealed four dielectric processes β, α, αβ, and ionic conduction phenomenon. Furthermore, it was found that incorporating MMT led to an increase in the dielectric losses and generated additional relaxation processes known as Maxwell–Wagner Sillars polarization. Calculation of the activation energy for the different processes revealed that α relaxation followed the Vogel–Fulcher–Tammann–Hesse dependency while the other processes were suitably fitted with the Arrhenius law. In order to probe matrix/MMT interface properties, dielectric strength of the interfacial polarization Δε is calculated by fitting the dielectric permittivity through the known Havriliak–Negami model. POLYM. COMPOS., 40:3333–3341, 2019. © 2018 Society of Plastics Engineers

No abstract