Synthesis and characterization superabsorbent‐ethanol polyacrylic acid gels

In this article, superabsorbent‐ethanol polyacrylic acid gels were synthesized by free‐radical aqueous polymerization method by using γ rays as initiator and varying the concentration of the Zn²⁺ from 0.1 to 0.3%, which acts as crosslinker. Effect of irradiation dose, monomer concentration, kind, and concentration of the crosslinker on swelling behaviors of polyacrylic acid gels were investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Swelling of High Oil-Absorptive Network Based on 1-Octene and Isodecyl Acrylate Copolymers

Crosslinked 1-octene-isodecyl acrylate copolymers were synthesized and evaluated for oil-absorbency application. The copolymer was crosslinked at different concentrations of ethylene glycol diacrylate (EGDA) and ethylene glycol dimethacrylate (EGDMA) crosslinkers via catalytic initiation or by electron-beam irradiation at dose rate 80 kGy. The concentration of both crosslinkers was varied from 0.5% to 2%. The effect of crosslinking conditions, such as crosslinker concentration, method of polymerization and monomers concentration on conversion and gel fraction was examined through an oil-absorption test using petroleum crude oil. It was found that, the oil absorbency was influenced mainly by the degree of crosslinking and the hydrophobicity of the copolymer units. The final equilibrium oil content, volume fraction of polymer and swelling capacity were determined at 298 K. The effective crosslinking density V_e, the average molecular weight between the crosslinks M_c and the polymer-toluene interaction parameter were determined from stress–strain measurements. The crosslinking efficiencies of EGDA and EGDMA towards copolymers were determined.     

影响熔纺氨纶质量因素探讨

分析了熔纺氨纶生产中的主要影响因素。指出聚氨酯切片质量、交联剂的选择及配比、纺丝温度、侧吹风条件、熟成等因素与熔纺氨纶质量的关系,只有把这些因素控制好,才能生产出品质优良的熔纺氨纶。     

多氨基硼交联剂的制备与性能评价

以多胺化合物和硼酸酯为原料,合成羟丙基胍胶压裂液用有机硼交联剂,通过在交联剂中引入多个含硼交联位点,达到降低压裂液体系中羟丙基胍胶的用量、提升压裂液体系耐温性能的目的。采用FTIR、1HNMR和11BNMR对不同交联剂的结构进行了表征,并分析了反应机理。考察了多胺化合物的种类(二乙烯三胺、四乙烯五胺、多乙烯多胺、聚乙烯亚胺-600)、反应物的配比、反应温度和反应时间对产物交联性能的影响,结果表明,当硼酸酯与多乙烯多胺的质量比为3∶2、反应时间为4h、反应温度为150℃时,可以制备性能最优的交联剂BNX-1。评价了BNX-1配制压裂液的耐温耐剪切性能、破胶性能和静态滤失性能。结果表明,以羟丙基胍胶质量分数0.35%、羟丙基胍胶溶液与BNX-1交联质量比100∶0.4配制的压裂液体系,在140℃、170s–1下剪切,120 min后黏度为122 mPa·s;以工业交联剂TCB-1作为对照(以羟丙基胍胶质量分数为0.5%、羟丙基胍胶溶液与TCB-1交联质量比为100∶0.5配制的压裂液体系),在同等条件下剪切,黏度为98 mPa·s。     

Preparation of free‐standing chitosan membranes for Chlorella vulgaris harvest and examination on suppression of algae‐fouling properties

Free‐standing chitosan membranes were prepared using genipin as crosslinker, using several molecular weights of polyethylene glycol (PEG) as a void‐forming agent. The membrane surface formation and chitosan polymer chain crosslinking were confirmed through SEM and FTIR, respectively. The water flux was remarkably increased with increasing molecular weight of PEG employed in preparation of composite chitosan membrane (J∝[PEG(MW)]0.85), it appeared over 6000 Da of PEG. During Chlorella vulgaris harvest using chitosan membranes, focus was made on algae‐fouling caused by the deposition of cells and extracellular organic matter, and it was found that membranes employing lower molecular weight of PEG (under 10000 Da) had been maintaining the high flux recovery after alternating filtration cycles, in addition to PEG20000 containing membrane. The chitosan membrane prepared with lower molecular weight of PEG exhibited better suppression of algae‐fouling properties. The Chlorella vulgaris harvesting results indicated that cell rejection rate reached above 98%.     

In situ fast transient fluorescence technique (FTRF) to study swelling of gels made of various crosslinker contents

The fast transient fluorescence technique (FTRF), which uses the strobe master system (SMS), was employed to study the swelling of disc‐shaped PMMA [poly(methyl methacrylate] gels. Seven gels were prepared by free radical copolymerization (FCC) of methyl methacrylate (MMA) with various ethylene glycol dimethacrylate (EGDM) contents. Pyrene (P_y) was introduced as a fluorescence probe during polymerization. After drying these gels, swelling experiments were performed in chloroform at room temperature. P_y lifetimes were measured from fluorescence decay traces during the in situ swelling experiments. An equation was derived for low quenching efficiencies to interpret the behavior of lifetimes in the gel during swelling. It was observed that P_y lifetimes in the gel decreased as swelling proceeded. The Li–Tanaka equation was used to determine the cooperative diffusion coefficients, D_c, which were found to decrease as the crosslinker content was increased. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 464–472, 2003     

交联PUA复合乳液的制备与性能

通过外加交联剂[二缩三丙二醇双丙烯酸酯（TPGDA）和三羟甲基丙烷三丙烯酸酯（TMP-TA）]合成了聚氨酯-聚丙烯酸酯（PUA）复合乳液。通过测定PUA乳液和涂膜性能，研究了交联剂用量对PUA乳液和涂膜性能的影响。结果表明，当交联剂TPGDA和TMPTA质量分数分别为0．6％和0．9％时，乳液涂膜性能最好。     

Research and Field Application of Polymer-Multiple Emulsion Crosslinker Gel for the Deep Profile Control

The authors describe a means to prolong gel time of Cr(Ac)₃-polyacrylamide gel system by coating the Cr(Ac)₃, forming the W₁/O/W₂ crosslinker. The white oil is the oil phase, and the sorbitol fatty acid esters are the water-in-oil emulsifier. The polyoxyethylene sorbitan monostearate is the oil-in-water emulsifier, which has a national patent (cf. Wang et al., 2009). The authors researched the effect of the reactants concentrations and reservoir environments are investigated to gelling behavior and plugging capacity such as temperature, salinity, and permeability. Compared to the Cr(Ac)₃ without coating, the multiple emulsion crosslinker obviously delays crosslinking and greatly increases gel time by about 3–4 times, so it is conducible to deep profile control. Reactant concentrations and temperature increase the gel strength and plugging capacity, but shorten gel time. Salinity causes gel time to shorten and lengthen, and gel strength weakens before it increases. Permeability reduces the plugging capacity and presents in linear relation in the log-log coordinate. Four wells were tested successfully in Shengli Oilfield from May to November 2008. The average injection pressure-added is 2.5 MPa, and approximately 3,200 tons of incremental oil was obtained with 6% water-cut decrease.     

聚碳化二亚胺类交联剂的性能及研究进展

介绍了皮革涂饰用聚碳化二亚胺类交联剂的性能及其与羧基反应的作用机理,并详细介绍了聚碳化二亚胺类交联剂的研究进展。