Micelles having UV absorbents at their coronas were prepared using a non-amphiphilic block copolymer. A vinyl phenol-b-4-(2- hydroxybenzophenoxymethyl)styrene-co-styrene diblock copolymer(I) showed no self-assembly in 1,4-dioxane because this solvent was non-selective to the copolymer. Light scattering studies demonstrated that the copolymer showed micellisation in the solvent in the presence of alpha,omega-diamine, producing micelles with a UV absorbent at the coronas. The critical micelle concentration(CMC) and the aggregation number of the micelles were dependent on the copolymer concentration and structure of the diamine. The copolymer at a lower copolymer concentration showed a higher CMC and produced micelles with a smaller aggregation number. The long methylene chain of the diamine and the intramolecular hydrogen bonding in the diamine prevented the copolymer from aggregating into micelles. The mixed micellisation of I and a diblock copolymer having azo dyes produced micelles with the UV absorbents and the dyes at the coronas. 23 refs.

Hindered amine light stabilisers(HALS) are discussed. Data are presented which demonstrate that, in addition to its efficient stabilising and radical scavenging action, the oligomeric HALS stabiliser Uvinul 5050 H from BASF exhibits some interesting processing advantages. These advantages are attributed to the low interaction of the product with other components in the compound or the production process.

The development of a new stabilisation concept for improvement of the heat and light resistance of coatings for interior and exterior automotive applications is described. The use of UV absorbers and hindered amine light stabilisers(HALSs) to protect coatings against sunlight is discussed. Experimental xenon weather-O-meter studies were conducted of the use of a 1:1 combination of a benzotriazole UV absorber and a HALS in solvent-borne and water-borne PU coatings on plaques of polycarbonate/polybutylene terephthalate blends. Accelerated weathering exposure and heat exposure on interior car part systems were also studied, the HALSs used acting as both radical scavengers and heat stabilisers. Additional solutions for convertible cars were examined. (ECS, Nuremberg, Germany)

Photoinitiated crosslinking polymerisation was used to prepare polyurethane acrylate, polyphenoxy acrylate, polyester acrylate and cycloaliphatic epoxide clay-based nanocomposites. The solvent-free resin containing 3 wt% of organophilic clay was cured within seconds on UV irradiation at ambient temperature. IR spectroscopy studies showed that the polymerisation reaction was rapid in thick samples (2 mm) because of the higher exotherm and the resulting rise in temperature. The organoclay did not slow down the photopolymerisation of either acrylate or epoxy resins. The presence of clay nanoparticles reduced the gloss of UV-cured coatings because of enhanced surface roughness. The viscoelastic and tensile properties of the nanocomposites were comparable to those of the neat UV-cured polymer but their moisture resistance was significantly increased. 35 refs.

Poly(styrene-b-methyl methacrylate) (P(S-b-MMA)) and poly(butadiene-b- MMA) (P(B-b-MMA)) diblock copolymers were solubilised in a liquid epoxy monomer (diglycidyl ether of bisphenol A). As in the solid state, the diblock copolymers were able to self-organise in solution to form well-ordered micellar structures. At room temperature, microsegregation of the PS or PB block occurred while the PMMA block (for which the epoxy was a good solvent) acted as a stabiliser of the microphase separation. The geometries and thermal stabilities of the ordered structures depended strongly on the molar masses and the chemical nature of the blocks of the copolymers. The total molar mass of the diblock copolymer had to be sufficiently high to obtain a periodic structure. However, if this molar mass was too high, the relaxation times were too long for the system to reach equilibrium. An order-disorder transition temperature was observed for the P(S-b-MMA) copolymer solution, which was attributed to solubilisation of the PS domains around this temperature. No order-disorder transition was observed for the P(B-b-MMA) copolymer solution because the PB blocks were not soluble in the epoxy at any temperature up to 200C. 44 refs.

Blending and dynamic vulcanisation of EPDM/HDPE blends using a resol/stannous chloride crosslinking system was studied in an extruder. The melting of the HDPE pellets occurred just in front of and in the first kneading zone and when the HDPE phase was completely melted, the EPDM/HDPE blends quickly reached their final morphology. High levels of crosslinking of the EPDM phase occurred before the HDPE phase was fully molten. The crosslinking rate increased with increasing EPDM content. For the EPDM/HDPE (50/50 w/w) thermoplastic vulcanisate, a transition from continuous via co-continuous to fully dispersed EPDM occurred which was driven by crosslinking. The degree of crosslinking of the EPDM was very high but this did not prevent phase inversion of the blend. The EPDM/HDPE interface was rather blurred because PE crystalline lamellae grew into the EPDM domains. This study showed that dynamic vulcanisation in extruders proceeded differently from that in batch kneaders where melting, mixing and crosslinking were separated in time. In extruders, mass and heat transport, melting of the thermoplastic, morphology development, distribution and dissolution of crosslinking chemicals and crosslinking of the rubber did not occur as independent phenomena but mutually and/or continuously interacted. 25 refs.

The novel profluorescent nitroxide, 1,1,3,3,- tetramethyldibenzo(e,g)isoindolin-2-yloxyl (TMDBIO) was studied as a probe for the formation of alkyl radicals during the degradation of unstabilised PP. Trapping of polymer alkyl radicals by the probe was observed during the induction period at 120C, when neither chemiluminescence nor IR spectroscopy techniques were able to detect changes in the polymer. TMDBIO also stabilised PP under thermooxidative conditions, which was consistent with its activity as a radical trap. The fluorescence decreased at elevated temperatures (150C), at the end of the "induction period" when the polymer was extensively degraded. This was because of secondary oxidation of the TMDBIO. 37 refs.

Low molecular weight melamine is often added to polyoxymethylene to enhance thermal stability by absorbing the formaldehyde which is generated during thermal degradation and accelerates the degradation process. The benefits of adding polyamide as a co-stabiliser were evaluated by isothermal weight loss analysis and non-isothermal thermogravimetric analysis. A synergistic effect on thermal stability was observed, and the impact strength was enhanced on addition of an appropriate amount of polyamide, or reduction of the melamine content. 14 refs.

The causes of the low stability of poly(vinyl chloride)(PVC) towards heat, UV light, oxygen or irradiation are reviewed in terms of mechanisms of dehydrochlorination and the presence of labile groups in the polymer chain. The use of additives to stabilise PVC is discussed, and the effects on service life of the production of PVC without labile groups in the polymer chain is considered. 46 refs.

The effects of a proprietary hindered piperidine ultraviolet light stabiliser on the weathering properties of various poly(vinyl chloride) roofing membranes were investigated by determining changes in colour and tensile properties on accelerated weathering tests. The results are discussed in comparison with those for benzophenone and benzotriazole type UV stabilisers. 8 refs.

The formation of nano-islands on the surface of conducting poly(3,4-ethylenedioxythiophene) films doped with poly(4- styrenesulphonate) using high energy ion irradiation, and characterisation of the modified films by SEM, AFM and cyclic voltammetry, is described. The mechanism of formation of the nano-islands is discussed in terms of micelle formation of the polymeric stabiliser, poly(sodium 4-styrenesulphonate). 28 refs.

The transition metal metallocene compound dichlorozirconocene, together with an anionic surfactant, sodium dodecyl sulphate (SDS), as emulsifier, was found to be an effective catalyst for the polymerisation of monomers such as styrene and methyl methacrylate in an aqueous medium. The polymers obtained had very high molecular weights with narrow molecular weight distributions. The added surfactant plays a dual role as a stabiliser for the cation and an emulsifying agent for the monomer. 27 refs.

Maleic anhydride (MAn) and vinyl acetate (VAc) were copolymerised in the absence of added stabiliser in a novel dispersion process that gives uniform copolymer microspheres with tuneable sizes. The stabiliser-free dispersion copolymerisation of MAn and VAc is rapid, and the particle size grows with the evolution of the polymerisation. Microspheres with uniform sizes ranging from 180 nm to 740 nm can be formed and stably dispersed over a wide range of monomer concentrations. The yield of copolymer microspheres reached a maximum at feed ratio of MAn to VAc of 1:1, as a result of the alternating copolymerisation between the binary monomers by a known charge-transfer-complex mechanism. However, the diameter of the microspheres increased markedly when the MAn content was increased. Only some specific alkyl ester solvents, such as butyl acetate, isobutyl acetate, or amyl acetate, are suitable for this stabiliser-free dispersion polymerisation. When some acetone was added as a cosolvent, copolymer microspheres were still formed, but they had much larger diameters. 46 refs.

Plastics additives makers have announced a series of price increases to restore margins. The most aggressive actions have been in flame retardants, where selling prices have eroded the most. The global plastics additives industry totalled 21.8 billion lbs, including plasticisers, in 2004, valued at 19bn US dollars. Plasticisers account for 58% of plastic additives volumes and 33-34% of value. Overall demand for plastics additives is growing at about 4%/year, with the Chinese market growing the fastest at 8-10%/year. The fastest-growing additives include anti-blocking agents, coupling agents, light stabilisers, nucleating and clarifying agents, and slip agents.

This paper presents the applications of polybranched hybrid organic-inorganic coatings. Nanoparticle-based dispersions made by sol-gel method have been prepared and the particle surface was modified to suit mixing with a variety of polymer materials. This method provides cost-effective crosslinkers or binders for organic-inorganic hybrid nanocoatings, especially when the nanobuilding block consists of inexpensive organic modifiers. Commercial lacquers can be modified with nanobuilding blocks based on organic-inorganic hybrid polymers. No changes in transparency, viscosity or shelf life of the lacquer have been observed. Cured coatings based on modified lacquer show clearly improved scratch resistance. 7 refs.

When it comes to assessing the heat resistance of plastic materials, the only attempt that most data sheets make to capture this capability is heat deflection temperature. However, one of the flaws contained in the HDT test is its failure to capture the effect of time on the properties of a polymer. The focus of this article is the chemical effect of prolonged elevated temperature exposure on a product. Antioxidants or heat stabilisers, although representing only a fraction of 1% of most formulations, govern to a great extent the effective lifetime of the product.

The kinetics of delamination in polypropylene nanocomposites were investigated. Use was made of fillers of montmorillonite, surface-treated with stearylamine and PPs of different flowabilities. There was also some variation in the processing conditions. It was found that the structure of the composites was only slightly affected by the processing parameters when a low molecular weight PP matrix was used. When a higher molecular weight polymer was used, under the effect of the mixing time, the separation distances of the layers increased. A good correlation was found between the torques and the peak intensity of the X-ray diffractograms of the composites. The delamination was found to be affected by two factors: the mobility of the polymer chains and the chemical polarity. Degradation of the matrix polymer also had an effect on the chemical interaction between the components, and the polar functional groups were found to be conducive to better adhesion between the filler and the polymer matrix. 10 Refs. (Article translated from Muanyag es Gumi, No.12, 2004, p.466-71).

It is claimed that the plasticisation of structurally inhomogeneous polymers with monomolecular plasticisers is not sufficiently effective because of the difference in the thermodynamic characteristics of the rubber and plasticiser microphases. This article reports on the synthesis of a new plasticiser based on the waste products from alcohol production. The waste products contained a mixture of ethyl, isobutyl and isopentyl alcohols and also chromatographically indeterminate components (3 wt.%). These were subjected to preliminary distillation with the aim of lowering the content of low molec.wt. fractions. The plasticisers were synthesised by the reaction of these waste products with phthalic anhydride in the presence of amphoteric and acidic catalysts. The products obtained were introduced into standard rubber mixes based on SKN-26ASM butadiene-acrylonitrile rubber. The properties of the mixes and vulcanisates containing the new plasticisers and dibutyl phthalate are tabulated. The results indicated that the products obtained are softeners which have similar properties to those of dibutyl phthalate, but which are less expensive. The best properties were found to be achieved in rubber mixes and vulcanisates with a plasticiser synthesised in the presence of an amphoteric catalyst. 4 Refs. (Article translated from Kauchuk i Rezina, No.4, 2004, p.46-7).