Characterization and applications of amino acid-bridged nano-Ag end-capped diblock copolymer

Ring opening polymerization of ε-caprolactone and tetrahydrofuran was carried outunder inert atmosphere with the monomer-to-initiator ratio of 100 and treated with AgNO to form Ag nanoparticle-centered diblock copolymer. Amino acids such as alanine (Ala) and asparagine (Aspar) were used as a lone chemical initiator at 160 °C in the presence of stannous octoate as a catalyst. The resultant Ala- and Aspar-bridged diblock copolymer was characterized by Fourier-transform infrared (FTIR), H nuclear magnetic resonance spectra, differential scanning calorimetry, thermogravimetric analysis, field-emission scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), gel permeation chromatography (GPC) and circular dichroism spectroscopy techniques. The FTIR spectrum showed a peak corresponding to the tetrahydrofuranium ion and confirmed the diblock copolymer formation. The diblock copolymer formation was confirmed by an increase in M in the GPC analysis. The HRTEM showed the size of the Ag nanoparticles was less than 10 nm. The Ag end-capped diblock copolymers were tested for catalytic reduction of p-nitrophenol (NiP) and the apparent rate constant (k) for the reduction of NiP was calculated as 1.15 × 10 s with the help of UV–Visible spectrophotometer. The Ag nanoparticle-centered diblock copolymer was tested for low-temperature splinting application. Mechanical properties of the polymers were also tested.