Papers by Keyword: Hyperbranched

Abstract: Hyperbranched polymer was prepared by the polycondensation reaction via the A₂+B₄ route. The polymer was obtained by the reaction of 1,3-tetramethyl-1,3-bis (methyl-dicholorosilyl) ethyl disiloxane and di-tert-butyl adipate. The obtained polymer was soft solid. The polymer was characterized by ¹HNMR and IR spectroscopies. The¹H NMR and IR analysis proved the existence of the branched structures in the polymer.

Abstract: Different hyperbranched polyester were synthesized by a simple one-pot melt polymerization method.The acid value,hydroxyl value and NMR were detected, we discussed the effect of proportion of DMPA,reaction temperature, vacuum level and vacuum time on acid value, hydroxyl value.The results show that the high efficient hyperbranched dispersant can be synthesized by the mass ratio of DMPA is 42.14%, vacuum time is 6h, vacuum degree is 30 kPa, and the stability kinetic is under 0.2.

Abstract: Hyperbranched polymer is a kind of non-linear polymers with highly branched structure and a lot of terminal groups. It has many advantages, such as high reactivity, good solubility and low viscosity. Hyperbranched polymer has become a focus in modern scientific domain. In this paper, polyester-type water-soluble hyperbranched monomer is prepared by the ring-opening polymerization reaction of maleic anhydride with polyol. Hyperbranched polyacrylate emulsion with 70-110nm was synthesized by emulsion polymerization using methyl methacrylate (MMA), butyl acrylate (BA), acrylic acid (AA) and hyperbranched polymer as comonomer. The effects of dosages and adding order of monomers, concentration of initator, type and amount of chain transfer agent on the polymerization are discussed. The as-prepared emusions were analyzed by FTIR, DSC, SEM. The solid content, particle size, stability of emulsion and morphology and water absorption of film were measured. The results showed that hyperbranched polyacrylate emulsion had low viscosity, high stability and can form very flat and smooth film. Hyperbranched polyacrylate emulsion can be widely applied in modern ink industry for its low cost,simple process and stable quality.

Abstract: Collagen fiber loaded hyperbranched polyamide-amine(CF-HBPN) was prepared by the crosslinking power of glutaraldehyde. The structure of CF-HBPN before and after adsorption was characterized and analyzed via scanning electron microscopy. The CF-HBPN was effective adsorbent for the removal of Cr(VI) from aqueous solutions. The adsorption isotherm and kinetic of the adsorption process were studied. The experimental results were fitted using the Langmuir, Freundlich and Temkin equations. The experimental results indicated that the Langmuir isotherm was better in describing the adsorption process. Two kinetic models, the pseudo-first order and pseudo-second order, were used to analyze the kinetic data. The pseudo-second order model was proven to be better in describing the adsorption behavior.

Abstract: Hyperbranched poly(diethynylbenzene-silane) (hb-PDEBS) was synthesized through polycondensation reaction of diethynylbenzene Grignard reagent (A₂) and trichlorosilane (B₃), and its structure was characterized by FT-IR, ¹H-NMR, GPC and Elemental Analysis. The degree of branching of hb-PDEBS was defined by ²⁹Si-NMR and calculated to be about 0.68. The curing behavior of hb-PDEBS was investigated by DSC. Thermal stability of cured hb-PDEBS was examined by TGA, and its residue at 1000°C under nitrogen was 80.6%. Hb-PDEBS displayed a strong absorption due to π-π^* transition and exhibited the most intensity structured emission with a maximum around 500 nm.

Abstract: Hyperbranched polyurethane (HPBU) was synthesized by the method of “arm first and core later”. The FT-IR and GPC were used to characterize the structure of HBPU. The results showed that the reaction happened as expected routine. Compared with common liner polyurethane, the Mn of HBPU increased 22% and Mw increased 37% at the same viscosity, which demonstrated that HBPU had advantage in low viscosity and easy flowing. The spectrum of X-ray shows the crystallinity of HBPU is higher than the PU, so the cell arranged of the HBPU is more regular.

Abstract: A novel triphenylene-based hyper-branched macromolecule was synthesized from the functional compound-2, 6, 10-trihydroxy-3, 7, 11–tris (pentyloxy) triphenylene serving as core, using α,ω-dibromodecane as spacer and 1-bromopentane as terminal group for end capping by using a very simple synthesis method, one-pot reaction. The structure of the hyperbranched macromolecule was determined by FTIR and 1HNMR. The molecule weight and the molecular weight distribution were measured by GPC. Mesophase and their structural orders were determined using a polarized optical microscope and a differential scanning calorimeter.

Abstract: In this paper, both lifetime and intensity in hyperbranched polymers were measured by using positron annihilation lifetime spectroscopy (PALS) measurements. Ortho-positronium properties upon the degree of branching (DB) have been studied; o-Ps lifetimes maintain a constant while an increase in o-Ps intensities has been detected with DB increasing. Which is inconsistent with author’s prediction and indicate that interactions between positronium and the free-volumes are strongly depend on not only the free-volume size properties but also its chemistry environment, due to the variations in the distribution of the different ending groups: –OH and -CH3, caused by DB changes in hyperbranched polymers. The present works demonstrate that in the polar-polymeric application of PALS, effects of the distribution of polar groups should be properly taken into consideration.

Abstract: Novel hyperbranched phenol-formaldehyde (HBPF) resin 1 has been prepared for the first time. Thorough characterizations (FT-IR, NMR, HPLC, MALDI-TOF MS and elemental analyses and rheological flow behavior) were performed to ascertain the structure of HBPF 1. The condensationcuring event of HBPF with diglycidylether of bisphenol-A (DGEBA) has been studied by differential scanning calorimetry (DSC) technique.

Abstract: Molded polyurethane foams for car seats are based on petrochemical polyols of molecular weight 4000-6000 and copolymer polyols containing micron size polymeric particles. Copolymer polyols (CPP) typically constitute 30% of the mixture with the base polyol. They help cell opening, increase load bearing and tear strength of the foams, but they are relatively expensive. Hyperbranched polyols of petrochemical origin were used in molded foams.[1] They are solid in the pure form and due to high crosslinking density could be incorporated at low concentration in conjunction with copolymer polyols. Instead, we have made hyperbranched polyols which could be a total replacement for CPP in molded foams. Six hyperbranched polyols with primary and secondary hydroxyl groups and different hydroxyl numbers were prepared from soybean oil and tested in flexible foams. Novel polyols were liquid even at very high molecular weights and could completely replace copolymer polyols. Functionality of these polyols increased linearly with molecular weight to very high values, resulting eventually in their high crosslinking power. The effects of the type of hydroxyl groups (primary vs. secondary), hydroxyl number (from 85 to 135 mg KOH/g), and concentration (7.5-30%) in the mixture with the base polyol on foam properties were analyzed. It was found that hyperbranched polyols could replace copolymer polyols completely but their effect on cell morphology and mechanical properties varied with the type of polyol and concentration.