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Glycidyl azide-butadiene block copolymers are potential binders for solid propellants. The azidic part contributes to the overall energy outputs, while the butadiene block improves the mechanical properties. Synthetic strategies proposed in literature are not appropriate for production of large-scale quantities. The mesylation of one homopolymer, followed by reaction with the OH terminal groups of the second is proposed here. The reaction is simple and does not show the drawbacks of the previously suggested alternatives. The block copolymers can be used as “partially” energetic binders. Moreover, they work well as compatibilizer in mechanical blends of the two homopolymers, that otherwise rapidly segregate in two distinct phases.

Polymer modified asphalts (PMA) and warm mix asphalts (WMA) are technologies widely adopted in the paving industry. The first one is well established, while the second one is relatively new, but rapidly growing since it guarantees economic and environmental advantages. Until now PMA and WMA have been used disjointedly, but it would be useful to combine them to keep the advantages of both. One of the adopted solutions to obtain a warm effect is the addition of waxes to the asphaltic binder. Therefore, a “warm mix polymer modified asphalt” may be potentially obtained with a ternary asphalt/polymer/wax system. However, the final warm effect and performances of the binder will depend on the interactions between the three components. A preliminary investigation was done by mixing asphalt, styrene-butadiene-styrene block copolymer and a wax chosen among the following three categories: paraffinic, partially oxidized and maleic anhydride functionalized. The morphological and calorimetric analyses and solubility tests allowed identifying different behaviors depending on the wax type, which may preferentially interact either with the asphalt or with the polymer, thus influencing the whole binder structure. With regard to the ternary mixes, it was found that: (i) the paraffinic wax preferentially resides in the polymer-rich phase, and slightly enhances the asphalt-polymer compatibility; (ii) the partially oxidized wax prefers the asphaltene-rich phase and reduces the compatibility; (iii) it is not clear where the functionalized wax is located, but it has a considerable compatibilizing effect and strongly alters the colloidal equilibrium of the asphalt-polymer blend. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Ternary systems, bitumen/ethylene-vinyl acetate (EVA)/organoclay, were prepared by two mixing methods (physical mixing and melt blending) and then studied in small amplitude oscillations, start-up of shear flow and repeated creep and recovery tests. The effect of mixing method and the role of two organoclays on the rheological properties of the studied systems were investigated. Improved thermomechanical properties of bitumen/EVA/organoclay nanocomposites, prepared by melt blending, were demonstrated by the low accumulated strain/compliance in the repeated creep and recovery tests. Structural differences between the studied systems were reflected in the behavior of the dynamic phase angle, specifically in the shape of the derivative of phase angle w.r.t. the reduced frequency. Similarly, the structural differences between the prepared nanocomposites were reflected by the behavior of the stress growth function η+ in the transient experiments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Morphology, thermal properties, and microhardness of ethylene-glycidyl methacrylate copolymer (EGMA)/clay and ethylene-acrylic ester-glycidyl methacrylate terpolymer (EAGMA)/clay nanocomposites with different clay concentrations have been studied. The results have shown that EGMA and EAGMA are highly compatible with the organoclays Cloisite ® 20A (Cl20A) and Cloisite ® 30B (Cl30B). Intercalated structures are formed in the whole range of Cl20A loadings investigated, whereas partial degradation of the Cl30B organoclay was observed. The thermal characteristics and microhardness of EGMA/clay nanocomposites suggest that the filler dispersion deteriorates at high concentration. The concentrated EGMA/Cl20A nanocomposites have been used as masterbatches to prepare ternary high density polyethylene (HDPE)/Cl20A and low density polyethylene (LDPE)/Cl20A nanocomposites. Diffractometric characterization and scanning electron microscopy observations of these materials have shown that the intercalated structure of the starting EGMA/Cl20A masterbatches is preserved after dilution with the polyolefins. The results suggest that the silicate platelets remain localized within the EGMA droplets in the diluted nanocomposites. The latter display improved microhardness, whereas the mechanical properties, including elongation at break, are comparable with those of the neat polyolefins. Considerable enhancement of the flame retardant properties has been observed for the ternary nanocomposites. P O LYM . ENG. SCI., 50:1306-1314, 2010. © 2010 Society of Plastics Engineers.

A model study for the recycling of the interior upholstery plastic parts of end-of-life cars has been carried out by reprocessing the homogenized scraps of an upholstery farm in the presence of different compatibilizer precursors, such as an ethylene-glycidylmethacrylate copolymer (EGMA), a maleic anhydride functionalized thermoplastic elastomer (SEBS-MA), etc. The investigated scraps contained recycled polyethylene (from agricultural uses) and poly(ethylene terephthalate), as the main components, plus minor proportions of polypropylene, polyamide-6, and other additives, including an ethylene copolymer (EC), probably an ethylene-acrylic acid copolymer, which is used to compatibilize the carpets' backing and increase their flexibility. The reactive blending experiments were carried out using a Brabender Plasticorder static mixer and a Brabender twin-screw compounder, and the products were characterized by rheometry, differential scanning calorimetry, scanning electron microscopy, stress–strain measurements, etc. It was shown that EGMA was most effective for the reactive compatibilization of the polyolefin and poly(ethylene terephthalate) components of the scraps. It was also found, however, that the EC contained in the upholstery backing neutralizes in part the functional epoxy groups of EGMA, thus reducing its compatibilizing efficiency. The results suggest that substitution of EC with an inert flexibilizing agent, such as an ethylene-propylene copolymer, and use of small amounts (∼ 5%) of an EGMA compatibilizer, might allow recycling of used upholstery into injection moldable plastic articles. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1716–1728, 2005

Ethylene/acrylic acid copolymers (EAA) with different acrylic acid (AA) contents have been used as compatibilizer precursors (CPs) for blends of two grades of lowdensity polyethylene (LDPE) with polyamide-6 (PA). In the first part of the work, binary blends of the CPs with LDPE and with PA have been studied in order to get an insight into the interactions of the EAA copolymers with the blends components. It has been shown that the CPs form immiscible, yet highly compatible, blends with LDPE. Investigation of the binary CP/PA blends provided evidence that acidolysis reactions occur between the carboxyl groups of the CPs and the amine and amide groups of PA, with formation of CP/PA graft (CP-g-PA) copolymers, although these reactions need relatively long times to go to completion. In the second part of the work, ternary LDPE/PA/CP blends have been prepared and characterized with a number of techniques. It has been shown that the addition of only 1-2 phr of CP into the LDPE/ PA blends is sufficient to enhance interfacial adhesion, to improve the minor phase droplet dispersion and to hinder coalescence. The effectiveness of the investigated CPs increases with an increase of the AA content from 6 to 11 wt.-%. Partial neutralization of the carboxyl groups of EAA with zinc also seems to improve the CP efficiency and this effect is thought to result from an acceleration of the acidolysis reactions responsible for the formation of CP-g-PA copolymers.

The compatibilization of blends of polyamide-6 (PA6) with linear low density polyethylene (LLDPE) and of poly(ethylene terephthalate) (PET) with high density polyethylene (HDPE), by functionalization of the polyethylenes with oxazoline groups was investigated. Chemical modification of LLDPE and HDPE was carried out by melt free radical grafting with ricinoloxazoline maleinate. Blends preparation was made either with a two-steps procedure comprising functionalization and blending, and in a single step in which the chemical modification of polyethylene with the oxazoline monomer was realized in situ, during blending. The characterization of the products was carried out by FTIR spectroscopy and scanning electron microscopy (SEM). The rheological and mechanical properties of the blends were also investigated. The results show that functionalization of the polyethylenes can be achieved by melt blending with ricinoloxazoline maleinate even in the absence of free radical initiators. The compatibilization of the blends enhances the dispersion of the minor phase significantly, increases the melt viscosity, and improves the mechanical properties. The one-step preparation of the compatibilized blends was also found to be effective, and is thought to be even more promising in view of commercial application.

Zinc alkylcyanocuprates (Knochel reagents) are found to be active in the cross-coupling reaction with allenic bromides affording acetylenic products with a high regio and stereoselective 1,3- anti substitution. The coupling process, which has been successfully extended to functionalized cuprates, can also be performed with alkylzinc chlorides in the presence of catalytic amounts of cuprous salts.