Polymer nanocomposites of epoxies with a novel filler, amino-functional butyltin oxide cage (stannoxane), were prepared and characterized. The nanofiller displays a promising antioxidizing effect, besides mechanical matrix reinforcement. The reinforcement can be assigned to physical interactions among the polymer bonded nanofiller. Moreover, the stannoxane cage undergoes a rearrangement to larger poly amino-functional nano-objects at higher temperatures, which highly reduces its extractability: it is practically not extractable from the nanocomposites in most cases. This, together with the fact that only a few weight percent are needed to achieve an optimal effect, makes it attractive as an antioxidative stabilizer. Epoxy–stannoxane nanocomposite synthesis, stannoxane reactivity and dispersion (morphology via TEM and SAXS), as well as the nanofiller effect on mechanical properties (DMTA) and on thermal stability are discussed. A brief comparison is drawn between the stannoxanes and the previously investigated POSS nanofiller.

The compatibilizing effect of di-, tri-, penta-, and heptablock (two types) copolymers with styrene and butadiene blocks was studied in polystyrene/polypropylene (PS/PP) 4/1 blends. The structure of PS/PP blends with the addition of 5 or 10 wt % of a block copolymer (BC) was determined on several scale levels by means of transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). The results of the structure analysis were correlated with measured stress-transfer properties: elongation at break, impact, and tensile strength. Despite the fact that the molar mass of the PS blocks in all the BCs used was about 10,000, that is, below the critical value M * (ϳ18,000) necessary for the formation of entanglements of PS chains, all the BCs used were found to be good compatibilizers. According to TEM, a certain amount of a BC is localized at the interface in all the analyzed samples, and this results in a finer dispersion of the PP particles in the PS matrix, the effect being more pronounced with S-B-S triblock and S-B-S-B-S pentablock copolymers. The addition of these two BCs to the PS/PP blend also has the most pronounced effect on the improvement of mechanical properties of these blends. Hence, these two BCs can be assumed to be better compatibilizers for the PS/PP (4/1) blend than the S-B diblock as well as both S-B-S-B-S-B-S and B-S-B-S-B-S-B heptablock copolymers. In both types of PS/PP/BC blends (5 or 10 wt % BC), the BC added was distributed between both the PS/PP interface and the PS phase, and, according to SAXS, it maintained a more or less ordered supermolecular structure of neat BCs.

The reaction between two non‐conducting chemicals, aniline and silver nitrate, yields a composite of two conducting components, polyaniline and metallic silver. Such conducting polymer composites combine the electrical properties of metals and the materials properties of polymers. In the present study, aniline was oxidized with silver nitrate in solutions of acetic acid; in this context, aniline oligomers are often a major component of the oxidation products. An insoluble precipitate of silver acetate is also present in the samples. The optimization of reaction conditions with respect to aniline and acetic acid concentrations leads to a conductivity of the composite as high as 8000 S cm−1 at ca 70 wt% (ca 21 vol%) of silver. A sufficient concentration of acetic acid, as well as a time extending to several weeks, has to be provided for the successful polymerization of aniline. Polyaniline is present as nanotubes or nanobrushes composed of thin nanowires. The average size of the silver nanoparticles is 30–50 nm; silver nanowires are also observed. Copyright © 2009 Society of Chemical Industry

The present contribution reports the single-step preparation of new type of soft macroporous conducting cryogels, a special type of hydrogels. Polyaniline/poly­(vinyl alcohol) cryogel was prepared by the oxidation of aniline hydrochloride in frozen reaction mixtures, in ice, containing a supporting polymer, poly­(vinyl alcohol). The cryogel used for illustration contained of polyaniline, poly­(vinyl alcohol) and 93 wt % of aqueous phase. It was macroscopically homogeneous and it had macroporous structure with average pore size of ≈100 μm. The conducting polyaniline phase was fibrillary. The molecular structure of polyaniline was confirmed by Raman spectroscopy. The conductivity of cryogel was 0.004 S cm–1 in water and 0.105 S cm–1 in 0.1 M sulfuric acid. It still increased to 0.29 S cm–1 when the content of monomer increased five times. Because of the contribution of electronic transport, the conductivity of cryogel was always higher than the ionic conductivity of aqueous phase used for its penetration. The conductivity of freeze-dried cryogel was 0.003 S cm–1. Viscoelastic and mechanical properties, controlled mainly by the conducting polymer phase, have been assessed and demonstrated good mechanical integrity and feasibility of potential applications.

Microfibrillar composites (MFCs) with reinforcing fibrils formed in situ by melt drawing were modified by the addition of layered silicates using different mixing protocols, viz simultaneous addition of components, application of respective premade nanocomposites and their combinations. The objective was to combine reinforcement with changes in the final structure, especially the fibril dimensions. The presented results indicate good potential of the nanoclay to enhance the MFC based on the melt-drawn HDPE/PA6 system. The best mechanical behavior was achieved with the simultaneous addition of all components. The majority of the nanofiller material was contained inside the PA6 fibrils. Both fibrils dimensions and mechanical behavior were significantly affected by the nanofiller migration to the PA6 phase in the course of mixing and melt drawing. Due to a complex effect of the clay, deterioration of mechanical properties was also found. As a result, numerous, in some cases contradictory, effects of nanofillers must be perfectly harmonized to improve the properties of MFCs.