Characterization Of Hyperbranched Polymers Research Articles

Synthesis and characterization of hyperbranched polymer with epoxide-terminated group and application as modifier for epoxy/polyamide system

Hyperbranched polymer with epoxide-terminated group was synthesized through end-capping reaction between hyperbranched polymer with hydroxyl-terminated group and epichlorohydrin. The chemical structure of the synthesized polymer was characterized by ATR-IR and 1H NMR spectroscopy. The influence of hyperbranched polymer content on the mechanical properties and fracture toughness of epoxy/polyamide systems was investigated. The toughening mechanism was discussed basing on observing the fracture surface morphologies of epoxy/polyamide/hyperbranched polymer system.

Synthesis and characterization of hyperbranched polymers via Cp2TiCl-catalyzed self-condensing vinyl polymerization using glycidyl methacrylate as inimer

Hyperbranched polymers were produced using glycidyl methacrylate (GMA)/Cp2TiCl2/Zn as self-condensing vinyl polymerization (SCVP) system. The polymerization is firstly initiated by the epoxide radical ring opening catalyzed by Cp2Ti(III)Cl generated in situ via the reaction of Cp2TiCl2 with Zn. By optimizing the molar ratio of the SCVP inimer (GMA) to the mediator (Cp2Ti(III)Cl), the active propagation chains are reversibly transformed to the dormant species and the cross-linking does not occur until a higher level of monomer conversion (ca. 80%). We detail this facile one-step polymerization technique to prepare highly branched polymers with a multiplicity of particular end reactive functionalities including Ti alkoxide, hydroxyl and vinyl functional groups, which differs from most previously reported SCVP systems.

Synthesis and characterization of hyperbranched polymers with increased chemical versatility for imprint lithographic resists

AbstractHyperbranched polymers were prepared from a variety of mono‐ and difunctional monomers and used in the development of novel UV‐imprint lithography (UV‐IL) resists. The unique physical and chemical properties of these hyperbranched materials significantly increase the range of molecular systems that could be imprinted. Traditional challenges, such as the use of monomers that have low boiling points or the use of insoluble/highly crystalline momomers, are overcome by the preparation of hyperbranched polymers that incorporate these repeat units. In addition, the low viscosity of the hyperbranched macromolecules and the large number of reactive chain ends overcome many difficulties that are traditionally associated with the use of polymeric materials as imprint resists. Hyperbranched polymers containing up to 12 mol % pendant vinyl groups, needed for secondary crosslinking during imprinting, were prepared with a wide range of repeat unit structures and successfully imprinted with features from tens of microns to ∼ 100 nm. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6238–6254, 2008

Novel synthesis and characterization of hyperbranched polymers

We approached a novel synthesis of hyperbranched polymers via living anionic polymerization. The first-generated star polymer (1G-S) was prepared by copolymerization of poly(4-methylstyrene)-block-polystyrene diblock anions with a small amount of divinylbenzene. The peripheral 4-methylstyrene units in the arm were metalated with s-butyllithium/tetramethylethylenediamine complex in cyclohexane. The second-generated hyperbranched polymers (2G-H) were prepared by equilibrium polymerization of such 1G-S polyanions with α-methylstyrene in tetrahydrofuran at −78°C, and subsequently the terminal branch ends were capped with a small amount of 4-methylstyrene. The characterization of such hyperbranched polymers was carried out in detail. The ratio values of radius of gyration (RG) to hydrodynamic radius (RH) for the 2G-H were in the range of 0.96–1.18. The 2G-H behaved like soft spheres or loose star-structures that were constructed with flexible chains in the inner parts.