The effects of POE-g-MAH, prepared through different methods, on morphology and properties of PA6/POE/POE-g-MAH blends are summarized in this article. The grafting degree of POE-g-MAH can be increased through the ultrasound-assisted extrusion. Experimental results showed that the addition of POE-g-MAH can increase the mechanical properties of the PA6/ POE blend and decrease the particle size of POE dispersed phase in PA6 matrix due to the compatibilization by POE-g-MAH. The PA6/POE blend compatibilized by POE-g-MAH prepared through the ultrasound-assisted extrusion has smaller particle size of POE dispersed phase and higher notched Izod impact strength than that by POE-g-MAH with similar grafting degree initiated only by peroxide. This result is ascribed to some anhydride rings attached to the chain terminus of POE due to ultrasound initiation. Rheological and Molau test results also showed enhanced compatibilization of POE-g-MAH prepared through the ultrasound-assisted extrusion on the PA6/POE blend due to a structural difference of POE-g-MAH.

The reaction of maleic anhydride (MAH) grafted onto propylene-based copolymer (DP) without adding any initiator was conducted through ultrasound assisted extrusion in this article. The effects of ultrasound power, die temperature, and MAH content on the grafting degree and efficiency were studied. With increasing ultrasound power, the grafting degree and efficiency of DP-g-MAH increase. The presence of ultrasound with higher power and lower die temperature is beneficial to increase the grafting degree and efficiency. The increase of MAH content can increase the grafting degree but reduce the grafting efficiency. Based on the results of melt flow index, dynamical rheological, gel permeation chromatograph (GPC), and Fourier transform infrared spectroscopy (FTIR) tests, the mechanisms of the grafting reaction were proposed. POLYM. ENG. SCI.,

Poly(3-n-octyloxythiophene), a conjugated polymer, which possessed solubility in common organic solvents, was synthesized by electrochemical polymerization in the presence of lithium perchlorate as the supporting electrolyte and sodium dodecyl sulfate as the surfactant in an aqueous medium. Characterizations of the intermediate, monomer, and polymer were performed by NMR spectroscopy, Fourier transform infrared spectroscopy, ultravioletvisible spectroscopy, and gel permeation chromatography. The process of electrochemical polymerization and the electrochemical redox behaviors were investigated by cyclic voltammetry and the potentiostatic method. A poly(3-noctyloxythiophene) film that was deposited on a platinum electrode was found to exhibit electrochromic behaviors, and it switched electrochemically between blue-green oxidized and dark red reduced states.

Propylene-based plastomer/nanosilica composites, with a filler content of 1-4 wt%, were prepared by a specially designed ultrasound-assisted extrusion system that was developed in our laboratory. The effects of ultrasound on the morphology, as well as the rheological and mechanical properties of the composites, were studied in this paper. In spite of slight ultrasound-induced degradation of the polymeric matrix, the results showed that the strength and elongation of the composites at break, in most cases, still improve in the presence of ultrasound because of ultrasound-induced homogeneous dispersion of nanoparticles in the polymeric matrix (as confirmed by scanning electron microscope, transmission electron microscope and differential scanning calorimetry studies). Dynamic rheological measurements also indicate that ultrasound-induced compatibilization has a more predominant role than does degradation. From dynamic mechanical measurements, it was found that ultrasound-induced degradation results in a drop in the dynamic storage modulus and glass transition temperature for composites with 4 wt% filler content, whereas ultrasound-induced compatibilization enhances their loss factor values. Polymer Journal (2011) 43, 91-96; doi:10.1038/pj.2010; published online 3 November 2010Keywords: extrusion; morphology; polymer-matrix composites (PMCs); properties; ultrasound INTRODUCTIONIn recent years, polymer/inorganic nanocomposites, in which the size of the dispersed particles is o100 nm in at least one dimension, have attracted tremendous interest in both academic and industrial researchers. Many studies report significant improvement in the desired properties of nanocomposites, such as their mechanical properties, barrier properties, optical transparency and solvent/heat resistance, compared with those of bulk polymers or conventional microcomposites. 1-3 These improvements can be achieved at a very low loading of the inorganic component (1-10 wt%) compared with conventional filled polymers, which require high loading (25-40 wt%). These studies indicate that polymer/inorganic nanocomposites are much lighter in weight and easier to process than conventional microcomposites. 4 To a large extent, improvement in these properties depends on the morphology and dispersion of the nanoparticles in the matrix. However, obtaining a homogeneous dispersion of nanoparticles in a polymeric matrix is a very difficult task when using only a simple mixing method, because of the strong tendency of nanoparticles to agglomerate. To break down the agglomerates of nanoparticles, many researchers have attempted various routes to prepare nanostructural composites in recent years, such as the sol-gel process, 5 in situ intercalative polymerization 6,7 and in situ polymerization in the presence of nanoparticles. 8 These methods, characterized by complex polymerization and special conditions, are not only incompatible with current industrial processes such as extrusion and injection molding, but are also inapplicable for the mass production of po...

The effect of ultrasound on flow behaviors of metallocene‐catalyzed linear low‐density polyethylene (mLLDPE) melt in capillary‐like die during the extrusion is investigated in this article. The rise in die temperature is found with increasing ultrasound power, especially at lower initial die temperature. At the same die temperature, the presence of ultrasound can decrease the apparent viscosity and the viscous flow activation energy of mLLDPE melt then increase its slip velocity at the capillary wall in the die. The flow behavior of mLLDPE melt is enhanced during ultrasound‐assisted extrusion as the presence of ultrasound can enhance the mobility and the orientation of entangled segments. It is also found that ultrasound can break the dispersed phase of mLLDPE/polyolefin elastomer (POE) blend into small pieces thus improve the homogeneous dispersion of POE phase in mLLDPE matrix. A possible mechanism for enhanced flow behaviors of mLLDPE melt because of the presence of ultrasound is also proposed. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers