Preparation and Characterization of Hybrid Nanocomposites Coated on LDPE

Abstract

Summary: Hybrid organic‐inorganic nanocomposites containing hyperbranched structures were prepared through a dual‐curing process, which involves photopolymerization and condensation alkoxysilane groups. In particular, an oligomer containing PEO units and α,ω‐methacrylate groups was used together with a HBP bearing acrylic groups as the organic phase precursors. MEMO, as the organic‐inorganic linker, and TEOS, as inorganic phase precursor, were also employed. The kinetics of both photopolymerization and condensation reactions were investigated by double bond conversion analysis (via FT‐IR) and weight loss determination, respectively. The mobility of the organic phase was studied by means of DSC and DMTA and correlated with hybrid composition. TEM analyses performed on microtomed film slices indicated the formation of nanoscale silica domains. Hybrids were coated onto an LDPE film previously subjected to a plasma treatment, and substrate‐coating interfacial adhesion was investigated through stress‐strain and DMTA experiments.Reaction scheme showing the insertion of furanic units in copolyester chains by ester interchange reaction.magnified imageReaction scheme showing the insertion of furanic units in copolyester chains by ester interchange reaction.

Organic−Inorganic Hybrids as Transparent Coatings for UV and X-ray Shielding

“…Owing to its pending methyl group close to carbonyl, PLLA interacts with titanium to a lower degree, thus maintaining its crystallizing ability in the hybrid, whereas crystallization of PCL and PBG is prevented by the strong interaction between these polymers and the inorganic phase. A similar behavior has been previously reported not only for PBG-containing hybrids (38) but also for silica-based hybrids containing a crystallizable polymer (44)(45)(46)(47), where crystallization of the polymeric component was found to be strongly reduced or even totally inhibited owing to organic-inorganic phase interaction.…”

UV-cured coatings based on waterborne resins and SiO2 nanoparticles

“…The use of a coupling agent can also be exploited to create chemical bonds between the two phases. 18 The aim of this work is to use the dual-curing process in the case of water-based resins and to prepare UV-cured nanocomposite coatings based on a waterborne polyurethane acrylic resin and containing nanosilica prepared in situ by sol-gel. The article presents a morphological investigation of the nanocomposites which allowed the determination of the best preparation conditions and chemical composition of the UV-curable mixture.…”

Organic–Inorganic Interactions in Poly(trimethylene carbonate)–Titania Hybrids

“…In the case of Hyb‐75, for which the highest number of TiOC covalent bonds was revealed by FT‐IR measurements (Figure 3), the interaction between the phases is so strong that almost no glass transition is detected, despite the fact that in this hybrid the amount of polymer is more than 50 wt.‐%. For Class II hybrids it was previously reported that the glass transition temperature of polymers whose chain ends are locked into the inorganic network increases upon hybrid synthesis 60–63. However the T g values reported in Table 3 show an opposite trend, with the T g in the hybrid samples being lower than in the PTMC polymer precursor.…”