Zhuomei Li

New water-soluble ampholytic polysaccharides for oilfield drilling treatment: a preliminary study

New water-soluble ampholytic polysaccharides with carboxybetaine groups, which were prepared by grafting the zwitterionic monomer 2-(2-methacryloethyldimethylammonio)ethanoate onto hydroxyethyl cellulose, have been tested for their properties as a multifunctional drilling-mud additive regarding clay hydration inhibition and mud rheological control. For the ampholytic polysaccharides investigated, an increase in carboxybetaine groups results in an enhanced inhibitive ability and the pH of the medium has an effect on the inhibition. A strong viscosifying efficiency for low-solid muds, especially for saline mud, has been observed.

Synthesis and characterization of new amphoteric graft copolymer of sodium carboxymethyl cellulose with acrylamide and dimethylaminoethyl methylacrylate

The graft copolymerization of sodium carboxymethylcellulose (NaCMC) with acrylamide (AM) and dimethylaminoethyl methylacrylate (DMAEMA) was conducted in an aqueous solution using ammonium persulfate (APS) and N,N,N′,N′-tetramethylethylene diamine (TMEDA) as the initiator. The effects of various factors on grafting, such as temperature, pH, initiator concentration, and concentrations of AM, DMAEMA, and NaCMC were studied. The composition and thermal stability of the graft copolymers were characterized by infrared, elemental, and thermogravimetric analysis, and degradation activation energy and kinetic order were calculated. The relationship between its reduced viscosity and pH in aqueous NaCl was also investigated.

Synthesis and aqueous solution properties of hydrophobically modified graft copolymer of sodium carboxymethylcellulose with acrylamide and dimethyloctyl(2-methacryloxyethyl)ammonium bromide

The hydrophobically modified water-soluble graft copolymer of sodium carboxymethylcellulose with acrylamide and dimethyloctyl(2-methacryloxyethyl)ammonium bromide has been synthesized using potassium persulfate and dimethylaminoethyl methacrylate as initiators in aqueous solution. The structure and composition of the graft copolymer were characterized by infrared spectrum and elementary analysis. Molecular weight was determined by gel permeation chromatography. The solubility and viscosity of the graft copolymers in aqueous solution were investigated, as a function of copolymer concentration, added salt, temperature, shear rate, and surfactant. In addition, the intermolecular hydrophobic association in aqueous solutions in the presence of added salt and surfactant was demonstrated through the retention time from gel permeation chromatography measurement.

Studies on new ampholytic cellulose derivative as clay-hydration inhibitor in oil field drilling fluid

A new ampholytic cellulose derivative (CAD) was prepared by grafting acrylamide and dimethyldiallylammonium chloride on carboxymethyl cellulose (CMC). The performance of CAD applied as a clay-hydration inhibitor in oil field drilling fluid was examined; the results showed that CAD had a hydration inhibitive property with better mud-making performance for low-solid mud. The mechanisms of the CAD inhibition of clay hydration were studied. The inhibiting-hydration performance of CAD was found to depend not only on cation, anion content, and molecular weight, but also on the cation–anion association in CAD chains.

New amphoteric graft copolymers of sodium carboxymethyl cellulose with acrylamide and dimethylaminoethyl methacrylate: Aqueous solution properties

The solubility and viscosity properties of new amphoteric graft copolymers of sodium carboxymethyl cellulose with acrylamide and dimethylaminoethyl methacrylate in aqueous solutions were investigated by turbidimetry and viscometry experiments. The factors investigated include the pH of the medium, the composition of the graft copolymer, the concentration and type of added salt, temperature, aging time, and the addition of organic solvent. Unlike conventional copolymers, these graft copolymers have unique solution behavior due to the presence of both acidic and basic groups along the macromolecular backbone. In addition, their solution properties are closely related to their conformations and are partially controlled by the net electrical charge and the ionic strength.

Novel modified cellulosic polymers as drilling fluid additives with improved properties

Novel modified cellulosic polymers with amphoteric character were prepared by grafting 2-dimethylaminoethyl methacrylate (DM) and 4-vinylbenzene sulphonic acid sodium salt (VB) onto sodium carboxymethylcellulose (NaCMC), and characterized by IR and composition analyses. Their properties as drilling-fluid additives in oilfields were investigated with respect to shale inhibition, filtration control and viscosity enhancement. It is found that the grafting of DM enhances the shale-inhibition effectiveness and that the grafting of VB increases the tolerances to salt and temperature. Different from commonly used anionic and cationic polymeric additives, the modified cellulosic polymer with suitable structural parameters has both good shale-inhibition and mud properties. © 1999 Society of Chemical Industry

Investigation of phase morphology, thermal behavior, and impact properties of polyamide‐1010/polystyrene blends compatibilized by lightly sulfonated polystyrene ionomers

The phase morphology, thermal behavior, and impact properties of polyamide-1010 (PA)/polystyrene (PS) blends compatibilized by sulfonated polystyrene (HSPS) and their zinc salts (ZnSPS) were investigated, using a dynamic mechanical analyzer (DMA), a scanning electron microscope (SEM), a differential scanning calorimetry (DSC), and a pendulum impact tester. It was found that the addition of the ionomer had an improved effect on the phase morphology of the resulting blends, where the HSPS was a more effective compatibilizer than was the ZnSPS due to its low melt viscosity and less self-agglomeration in the PA matrix. DSC results showed that with increasing the ionomer content the amount of the less perfect crystals of PA increased in these blends and, hence, led to a small increase in the crystallinity of the PA phase. The crystallization rate of the PA in the resulting blends was accelerated slightly by the ZnSPS but was decreased by the HSPS, which was probably due to the nucleation effect of ZnSPS for PA but no nucleation of HSPS. The best improvement in the notched impact strength of the blends was achieved with the content of the ionomer up to 20 wt % based on the amount of PS.

Spectroscopic studies of the anomalous viscosity‐temperature relationship of sulfonated EPDM ionomer solution

FTIR and ESR studies of sulfonated EPDM ionomers in xylene/alcohol show that alcohol solvation of SO3M occurs and the extent of solvation relates to the species and concentration of the metallic ions and the molar concentration of OH from the cosolvent (alcohol) and temperature. The relationship between these factors and the viscometric behaviors of the ionomer solution were investigated. The results of these two studies are quite consistent with each other. At the molecular level the solvation of the metallic ion with the cosolvent plays a key role in the anomalous viscosity-temperature behavior of ionomer solutions.

Studies on acrylate copolymer soap‐free waterborne coatings crosslinked by metal ions

Acrylate copolymers containing hydrophobic monomers (methyl methacrylate, butyl acrylate, styrene, or divinyl benzene) and hydrophilic monomer (acrylic acid) were synthesized by solution polymerization, and neutralized to form the soap-free hydrosol. The waterborne coating was prepared from the hydrosol crosslinked by M(NH3) (M2+ was Zn2+ , Cu2+, Ni2+ or Co2+). 13C-NMR analysis was used to identify the copolymer. The result of GPC showed that the molecular weight of the copolymer was within the range of thermosetting resin for coating. The factors affecting the crosslinking degree of the coating films were studied by DSC and gravimetric analysis. The results indicated that the appropriate crosslinking agent was Zn(NH3), and the optimum curing condition was heating at 80°C for 30 min.