Summary: A study of the structure–property relationships for nanocomposites prepared by melt compounding from ethylene–acrylic acid copolymers of varied composition and molecular architecture, and organoclays modified with different ammonium ions has been made by DSC, POM, SEM, TEM, WAXD, and rheological and mechanical tests. Within the series of clays investigated, the best levels of dispersion were displayed by those organically modified with quaternary ammonium ions containing two long alkyl tails. The relevant nanocomposites were shown to possess mixed exfoliated and intercalated morphology. The spacing of the intercalated clay stacks, most of which comprise few silicate layers, was found to be independent of clay loading, in the range of 2–50 phr, and to change with the molecular architecture of the matrix polymer. An indication that the excess surfactant present in some of the clays, and the organic material added in others to expand the interlayer spacing, were expelled from the clay galleries during melt blending and acted as plasticisers for the matrix polymer, was obtained from WAXD and rheological characterisations.
TEM micrograph of the nanocomposite of EAA1 with 11 phr of 15A. 相似文献
There is a growing need and special attention for using textile products to provide effective protection against such damage of UV-radiation, i.e., skin cancer, sun burn, and photo-aging, in the recent years. In this research work a new approach for upgrading the UV-protective properties of cotton/wool and viscose/wool blended fabrics for high quality/trans seasonal apparel, was investigated. Factors affecting the UVB-protection function of the aforementioned substrates such as type and concentration of finishing additives, as well as subsequent treatment with cu-acetate or dyeing with anionic or cationic dyes were studied. The experimental data show that: i) the enhancement in the UV-protection factor (UPF) of the finished fabrics is determined by the type of finishing additives, i.e., citric acid ≥ aspartic acid ≥ tartaric acid ≥ none, chitosan TEA.HCL ≥ choline chloride ≥ none, β-cyclodextrin CMC-30 PEG-600 > none, and Siligen® WW > W Siligen® PEP ≥ Leomin® NI-ET ≥ none, regardless of the used substrate, ii) UPF values are governed by the type of substrate, i.e., viscose/wool ≥ cotton/wool, irrespective of the used additives, iii) post-treatment with cu-acetate or post-dyeing with the used dyestuffs brings about a dramatic improvement in UPF values, and iv) UPF values are determined by the finishing regime and follow the descending order: Resin finishing → post dyeing > resin finishing → posttreatment with Cu-acetate > resin finishing in presence of additives > resin finishing in absence of additives. 相似文献
ABSTRACT A series of copolymers, based on 2-ethylhexylacrylate (2-EHA) and butylacrylate (BuA), and functionalized with small amounts of acrylic acid (AA) were synthesized by emulsion polymerization techniques and monodisperse latexes were obtained. Their average particle size and particle size distribution were determined by quasi-elastic light scattering and confirmed by transmission electron microscopy. The change in the adhesive properties (peel, shear, and tack) as a function of 2-EHA/BuA ratio was studied. An optimal balance between these three properties was determined at a 2-EHA/BuA ratio 10/90 wt/wt. The influence of the functionalization of these copolymers with AA was also evaluated when the comonomers ratio was kept constant. Good results were found at an AA content of 1 wt%. 相似文献
Nanostructuration of maleate and orthophthalic unsaturated polyester (UP) resins was achieved by the use of high molecular weight amphiphilic PBA‐b‐P(MMA‐co‐DMA)2 triblock copolymers. PBA is fully immiscible in cured UP resins, and the miscibility of P(MMA‐co‐DMA) random copolymers can be ensured with a minimum DMA content of 12 mol‐%. When using the triblock copolymers, fully transparent and nanostructured thermosets are obtained with a minimum DMA content in the outer blocks; the value of which is higher than 12 mol‐% and depends on the UP chemical structure. Finally, the fracture toughness of nanostructured thermoset was evaluated: for a triblock copolymer content as low as 5 wt.‐%, a 50% increase of KIc was obtained, as compared to the neat thermoset.
