Guorong Qi

Functional poly(carbonate-co-ether) synthesis from glycidyl methacrylate/CO2 copolymerization catalyzed by Zn–Co(III) double metal cyanide complex catalyst

Polycarbonates with pendant functional groups have attracted much attention due to their capability for further chemical modification and post-polymerization. This work describes the synthesis of a poly(carbonate-co-ether) with massive pendant acrylate groups from the copolymerization of glycidyl methacrylate (GMA) with carbon dioxide (CO2), using a nanolamellar zinc-cobalt double metal cyanide complex (Zn–Co(III) DMCC) catalyst. The carbonate linkage content (FCO2) of the poly(carbonate-co-ether) could be varied from 42.2 to 68.0% by changing the polymerization conditions. Of importance, 4-methoxyphenol was applied for regulating the copolymerization. It could not only act as an inhibitor for completely depressing the self-polymerization of GMA via free radical polymerization of the double bond, but also modulate the molecular weight of the resultant copolymers. The obtained copolymer had two terminal hydroxyl groups, which were confirmed by the electrospray ionization-tandem mass spectrometry (ESI-MS) technique. A new thermoset with high glass transition temperature (Tg: 105 or 120 °C) and massive carbonate units as well as hydroxyl (or carboxylic) groups was prepared by the curing reaction of the GMA–CO2 copolymer with allyl alcohol or acrylic acid in the presence of 2,2′-azobisisobutyronitrile (AIBN).

Synthesis of bis(cyclic carbonate) and propylene carbonate via a one-pot coupling reaction of CO2, bisepoxide and propylene oxide

The effective transformation of carbon dioxide (CO2) into valuable products is promising in green and sustainable chemistry. The coupling reaction of CO2 with epoxides to afford cyclic carbonates is an atom-economic pathway for CO2 fixation. Many catalysts have been developed for this coupling reaction, however, very few of them were reported for the coupling reaction of CO2 with bisepoxides. This work describes an efficient one-pot coupling reaction of CO2, propylene oxide (PO) and bisepoxides without the addition of external organic solvents by using a nanolamellar zinc-cobalt double metal cyanide complex (Zn–Co(III) DMCC) as the catalyst and cetyltrimethyl-ammonium bromide (CTAB) as the co-catalyst. Propylene carbonate (PC) and bis(cyclic carbonate)s were obtained at the same time with high monomer conversions (PO: 93.6%, bisepoxides: 82.9%). The in situ produced PC acted as a good solvent for the coupling reaction of CO2 with bisepoxides. Two products could be easily separated by distillation or precipitation. The application of the obtained bis(cyclic carbonate)s was also preliminarily investigated. A non-isocyanate route for synthesizing polyurethanes with massive hydroxyl groups was proposed.

Synthesis of fully alternating polycarbonate with low Tg from carbon dioxide and bio-based fatty acid

The selective copolymerization of CO2 and an epoxide to form fully alternating polycarbonates is a great challenge via catalysis with the zinc–cobalt(III) double metal cyanide complex [Zn–Co(III) DMCC]. We describe the first perfectly alternating copolymerization of CO2 with a bio-based epoxide. The resultant polycarbonate had a low Tgs of −38 to −44 °C and two end hydroxyl groups, which were then used to initiate ring-opening polymerization of L-lactide via metal-free catalysis, affording a biodegradable triblock copolymer. This study provides a new platform copolymer for making various advanced polymers with biodegradable properties.

Thermodynamic analysis for the interaction of polyacrylate with wax in heptane

Abstract The effect of polyacrylate (PA) on wax-precipitation temperature in heptane was investigated using differential scanning calorimetry (DSC). A thermodynamic analysis for the dissolution of wax in the absence and presence of PA was conducted. Results suggested that the change in wax-precipitation temperature caused by the introduction of the additives may be regarded as an index for characterizing the interaction of polymer additives with wax.

Assessment of polymer flow improvers for crude oil by viscometry

A new parameter has been developed to assess the efficiency of polymer flow improvers for waxy crude. The flow parameter, Q, depends on the interaction parameter for polymer-wax and polymer-resin-asphaltene, and is calculated by dilute solution viscometry. It was established that the improvement in rheological properties of doped crude oil, such as the reduction of apparent viscosity, pour point and temperature of wax crystallization, is inversely proportional to the Q values for the polymer-wax and polymer-resin-asphaltene mixtures.

Association of ethylene-vinyl acetate copolymer in dilute solutions—I. Solvent, concentration and annealing temperature effect

Abstract Viscometric behaviors of dilute solutions of random ethylene-vinyl acetate (EVA) copolymer in the temperature range of 5–65 °C in four solvents: 1,2-dichloroethane, cyclohexane, xylene and chloroform are studied. It is found that association of EVA molecules occurred by two patterns of intrachain and interchain interactions. The degrees of association are dependent on solvent properties, EVA concentrations and annealing temperature of preparation of EVA solution.

Solvent effect on the action of ethylene–vinyl acetate copolymer pour point depressant in waxy solutions

The flowability and thermal behavior of waxy solutions with and without an ethylene–vinyl acetate copolymer (EVA) have been studied. The drastic changings of pour point depression (ΔTpp) and the crystallization in four waxy solutions were observed. These changes were linear with the U-interaction parameters between EVA and wax in different solvents, suggesting that the efficiency of EVA pour point depressent depends on its compatibility with wax, which is affected by solvent.

Interpolymer specific interaction in blends of poly(styrene-co-alkyl acrylate-co-4-vinylpyridine) and poly(styrene-co-alkyl acrylate-co-acrylic acid)

Abstract The interpolymer specific interaction of proton donating polymer (PDP) and proton accepting polymer (PAP) in toluene was studied by viscometry coupled with light scattering. The viscometric experiment results show that the stronger the interpolymer interaction is, the higher the viscosity of PDP/PAP blend solution than the weight-average of both components at high concentration, in contrast to lower viscosity at low concentration. Based on the relationship of viscosity enhancement factor with polymer level in solution, a new polymer–polymer interaction parameter k a to estimate interpolymer interaction was developed. The effects of functional groups content and acrylate unit on interpolymer interaction were studied with this parameter combined with light scattering. The results show that interpolymer interaction ability increases with the functional group and long chain alkyl acrylate content. With the increase in side chain length of acrylate unit, enhancement in the interpolymer specific interaction can be realized.

Association of ethylene vinyl acetate copolymer in dilute solutions. V. Stability and pour point depression to wax solutions

The stability of two kinds of aggregation states of ethylene vinyl acetate (EVA) copolymer in dilute solution of 1,2-dichloroethane has been investigated by viscometry. It was found that good storage-time, shearing, and dilution resistance were displayed for both states of EVA molecule with intra- and interchain association. And for the pour point depression of wax solution doped with EVA, the EVA in intrachain aggregation state was better than the EVA in interchain aggregation state.

n-DIOCTADECYL FUMARATE–VINYL ACETATE COPOLYMER: SYNTHESIS, CHARACTERIZATION AND APPLICATION AS FLOW IMPROVER FOR OILS

ABSTRACT Monomer n-dioctadecyl fumarate (DOF), and copolymers (C18FVA) of DOF with vinyl acetate were synthesized. Monomer and copolymers were characterized by IR, 1H-NMR, VPO and DSC. Due to the special structure of DOF, only copolymers containing 45.9%–97.8% (mol) DOF were obtained. The crystalline CH2 numbers on polymer side chain χ were calculated from enthalpy determined by DSC, and it was found that χ slightly decreased with increasing vinyl acetate content. C18FVA can be used as flow improver for viscous oil and residual oil, and the more the crystalline CH2 number on the side chains, the better lattice match between copolymer and wax crystal structure of oils.