Polymer nanocomposite

About: Polymer nanocomposite is a research topic. Over the lifetime, 8977 publications have been published within this topic receiving 297599 citations.

Synthesis of metal-polymer nanocomposite for optical applications

Abstract: Thin films of Ag‐PET nanocomposite were synthesized by a novel route of atom beam co-sputtering. The nanocomposites were characterized by UV‐visible and IR absorption spectroscopy, Rutherford backscattering spectroscopy and transmission electron microscopy. The absorption spectra exhibit features suitable for applications as (i) absorber extending from the visible region to about 2400 nm in the infrared region and (ii) bandpass filter at 320 nm, useful for HeCd laser. The transmission electron microscopy observations indicate that the metal fraction is in the form of fractals. (Some figures in this article are in colour only in the electronic version)

Decoration of carbon nanotubes with silver nanoparticles for advanced CNT/polymer nanocomposites

Abstract: We have successfully decorated carbon nanotubes with silver (Ag–CNTs) using N, N-dimethylformamide (DMF) as a reductant. The Ag–CNTs were charactered by TGA, XRD, TEM and Raman spectra to confirm that silver nanoparticles were uniformly decorated onto the CNTs. Then the Ag–CNTs were used as fillers to prepare the nanocomposites with two polymers: polypropylene (PP) and polystyrene (PS) by means of two different methods: i.e. melt compounding and solution mixing, respectively. The results showed that the Ag–CNTs could effectively improve the electrical conductivity and mechanical properties of PP and PS as compared to pristine CNTs. It was found that the solution mixing was better than the melt mixing in terms of dispersion of CNTs and electrical conductivity. The mechanisms for the results have been discussed.

Grafting Bimodal Polymer Brushes on Nanoparticles Using Controlled Radical Polymerization

Abstract: RAFT (reversible additionfragmentation chain transfer) poly- merization has been widely used to synthesize different polymer architectures such as polymer brushes on nanoparticles for incorporation into polymer nanocomposites. It is believed that these polymer brushes, with the same chemistry as the matrix polymer, can be employed to improve filler dispersion by compatibilizing unfavorable enthalpic interactions between the inorganic nanoparticles and their organic host matrices. However, monomodal brush graft nanoparticles are found to aggregate into a range of isotropic and anisotropic morphologies, formed due to a delicate balance between enthalpic and entropic interfacial interactions. This coupling of enthalpy and entropy leaves only a small window of graft densities and molecular weights to obtain randomly dispersed filler morphologies. These issues can be countered by using a bimodal polymer brush that contains a small number of long homopolymer chains that can entangle, and a high density of short brushes that screens the particle/particle attraction, thereby aiding in decoupling the interfacial enthalpic and entropic interactions. In the present work, we demonstrate a robust step-by-step technique using RAFT polymerization to synthesize these bidisperse/bimodal polymer brush-anchored nanoparticles. A layer of dense brush of the first population was initially prepared using surface-initiated RAFT polymerization from colloidal silica nanoparticles. After cleavage of the chain transfer agent from the first population of chain ends, a second RAFT agent was attached onto the silica nanoparticles and then a monomer, which may be the same or different from the first brush, was polymerized. This versatile and widely applicable route enables us to independently control the molecular variables of the attached chains, such as composition, molecular weights and graft densities of the individual populations. The bimodal brush-grafted colloidal silica nanoparticles show superior dispersion and interaction with a homopolymer matrix when compared to monomodal brush-grafted particles.