14860-75-4Relevant academic research and scientific papers
Controlled synthesis of azobenzene functionalized homo and copolymers via direct acyclic diene metathesis polymerization
Ding, Liang,Xu, Mengyu,Wang, Jingjing,Liao, Yang,Qiu, Jun
, p. 1681 - 1687 (2014/04/03)
A powerful and efficient strategy for obtaining a series of azobenzene functionalized linear unsaturated polyolefins is described, which involves the first design and synthesis of three different α,ω-diene monomers with different reactivity of acrylates and terminal double bonds and their subsequent acyclic diene metathesis (ADMET) polymerization under mild reaction conditions. Different ruthenium based metathesis catalysts and conditions were tested to optimize the ADMET polymerization of these monomers. Besides, this polycondensation method is also reported allowing for the synthesis of alternating and diblock azobenzene-containing copolymers with molecular weight control by using the selectivity of olefin cross-metathesis between acrylates and terminal olefins. The resulting polymers showed well-defined molecular weights, reasonable polydispersity index, and reversible photoresponsive behavior. This special combination of the benefits of metathesis polymerization and azobenzene is a highly versatile system for materials in many applications.
Synthesis of azobenzene-functionalized star polymers via RAFT and their photoresponsive properties
Alam, Md. Zahangir,Shibahara, Akihisa,Ogata, Tomonari,Kurihara, Seiji
, p. 3696 - 3703 (2012/02/05)
Azobenzene-functionalized star polymers were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. First, azobenzene-functionalized linear macro chain transfer agents (Macro-CTA) were synthesized by RAFT polymerization of 6-[4-(4′-Methoxyphenylazo)phenoxy] hexylmethacrylate (MAz6Mc) using 2-(2′-cyanopropyl)dithiobenzoate (CPDB) as RAFT agent in presence of AIBN as initiator in anisole. Subsequently, star azopolymers were synthesized by polymerization of a difunctional azomonomer, BMA2Az, with resultant Macro-CTA in presence of AIBN as initiator in anisole. Star azopolymers were characterized by GPC and spectroscopic methods. Thermal properties of star azopolymers were determined by DSC and TMA. Molecular weight versus conversion and molecular weight versus polymerization time attest to living polymerization characteristics. Photoisomerization behaviors of star azopolymers were studied by irradiation of both UV and visible light. Surface relief gratings were inscribed on star azopolymer films upon exposure to an interference pattern of (RCP + RCP) Ar+ laser. A diffraction efficiency of 20% was obtained by exposure of Star-8 K(2.6 K) polymer film to an (RCP + RCP) Ar+ laser for about 30 min. Surface relief grating structures were investigated by AFM and polarized optical microscopy.
