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Characterization study of polyAMPS@BMA core-shell particles using two types of RAFT agents

Shah Nasrullah, Khan Zubair Ullah, Hussain Manzoor, Rehan Touseef, Khan Abbas

Materials Science Poland

2021

Vol. 39, No. 2

200--208

The study and application of reversible addition-fragmentation chain transfer (RAFT) polymerization have been widely reported in the literature because of its high compatibility with numerous monomers, reaction conditions, and low polydispersity index. The effect of RAFT agents on the characteristics of the final product is greatly needed to be explored. Our present study aimed to compare the influence of two different types of RAFT agents on the characteristics of the water-soluble polymer (2-acrylamido-2-methylpropane sulfonic acid) (polyAMPS) and their polyAMPS@butyl methacrylate (BMA) core-shell particles. Different analytical techniques including scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were used to ascertain the final morphological, structural, and thermal properties of the resultant products. It was found that RAFT agents have shown a clear influence on the final properties of the resultant polyAMPS and their core-shell particles such as particle size, shape, size distribution, and thermal behavior. This study confirms that RAFT agents can control the final properties of the polymers and their core-shell particles.

Modification of epoxy-polyester and polyester powder coatings with silicone-acrylic nanopowders – effect on surface properties of coatings

Ofat I., Kozakiewicz J.

Polimery

2014

T. 59, nr 9

643--649

Zaprezentowano wyniki badań wpływu modyfikacji poliestrowo-epoksydowych i poliestrowych farb proszkowych, za pomocą silikonowo-akrylowych cząstek o budowie rdzeń–otoczka, na właściwości powierzchni otrzymanych z nich powłok. Metodami mikroskopii konfokalnej (CM) i mikroskopii sił atomowych (AFM) określono topografię, a za pomocą skaningowego mikroskopu elektronowego wyposażonego w spektrometr dyspersji energii (SEM-EDS) oraz spektroskopu fotoelektronów (XPS) badano skład pierwiastkowy. Metodą kropli osadzanej wyznaczono kąt zwilżania (CA) i swobodną energię powierzchniową (SFE). Stwierdzono, że modyfikacja farb proszkowych za pomocą silikonowo-akrylowych nanocząstek polimerowych wpływa na zwiększenie wartości CA oraz zmniejszenie wartości SFE, co może być spowodowane migracją żywicy silikonowej do powierzchni powłoki. Obecność silikonu na powierzchni próbki potwierdzono za pomocą EDS, a badanie XPS wykazało tendencję do zwiększania się ilości silikonu w powłoce w kierunku powierzchni próbki. Zauważalny jest również wpływ modyfikatorów silikonowo-akrylowych na strukturę powierzchni.

The effect of modification with 3 wt % of nanopowders containing silicone-acrylic core-shell nanoparticles (size ca. 100 nm) on surface properties of epoxy-polyester and polyester powder coatings was investigated. Contact angle (CA) determinations, atomic force microscopy (AFM), confocal microscopy (CM), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) were used to assess this effect. It was found that the modified coatings showed significantly higher CA values and significantly lower surface-free energy (SFE) values as compared to unmodified ones what could be explained by migration of silicone resin contained in nanopowder to the coating surface due to specific features of silicone polymer. Using XPS and EDS the presence of silicone on the surface was confirmed, and AFM of modified coatings revealed structures on the surface which could be attributed to nanoparticles of silicone resin. It was stated that the chemical structure of silicone resin influenced very much surface properties of the coatings.

Electrical conductivity in thin films fabricated from nanoparticles of a polymeric composite based on PEDOT

Rais D., Hain J., Pich A., Pochekailov S., Nešpůrek S., Adler H. J. P., Hamáček A., Řeboun J.

Materials Science Poland

2009

Vol. 27, No. 3

769--780

A comparative study of electrical properties of films fabricated from a series of polymeric core shell particles and microgels is presented. The core shell particles consist of spherical polystyrene core covered by electrically conductive poly[3,4-(ethylenedioxy)thiophene] (PEDOT). Microgels are composed of PEDOT grains embedded into crosslinked, electrically insulating polymer bodies. The electrical resistivity of the films changes from 12 G?ˇcm to 100 ?ˇcm; the value depends on the thickness of the shell cover and the type of oxidant used for PEDOT polymerization. Electrical conductivity in the films of core shell particles is thermally activated and obeys the inverse Meyer-Neldel rule, which indicates that the electrical conductivity is governed by a common transport mechanism. Electrical conductivity depends, among others, on the humidity in the surrounding environment. In films consisting of particles with a high PEDOT content (and thus high conductivity) the resistivity increases as the humidity increases. Conversely, when the films are formed from particles having a low PEDOT content, the humidity has a reverse effect. An explanation for this behaviour is proposed. The frequency dependences of ac conductivities of high conductivity "core shell" and "microgel" films suggest existence of hopping charge carrier transport mechanism for large humidity scale.