Preparation and Water Absorbent Behavior of Superabsorbent Polyaspartic Acid Resin

Superabsorbent polyaspartic acid (PASP) resin was prepared from high molecular weight polysuccinimide (PSI), which was synthesized from l-aspartic acid by thermal polycondensation. The effects of the reaction temperature, the reaction time, the concentration of the solvent, the molecular weight of PSI, the concentration of the cross-linking agent, the hydrolysis conditions, and the drying temperature on the swelling ratio of PASP resin were investigated. The swelling ratios of PASP resin in deionized water and saline solution were measured, and the biodegradability of PASP hydrogel was evaluated. The results show that the swelling ratios of PASP resin in deionized water were 100–1,120 g/g depending on the preparation conditions. The swelling ratio of PASP resin in saline solution reached 143 g/g, and PASP resin was a kind of biodegradable material with high water absorbency, so this PASP resin can be used as agricultural and horticultural water-holding material, and in manufacturing of diapers, sanitary napkins, medical products, etc.     

以凝胶时间表征环氧树脂6101固化反应动力学方程

由旋转黏度计测定了环氧树脂6101分别与3种固化剂所形成的体系在固化过程中剪切黏度随时间的变化曲线,用环形剪切法处理获得相应的凝胶时间。考察了凝胶时间与固化剂、溶剂含量及固化温度等的变化规律,并以凝胶时间作为固化速度的表征,分别建立了相应体系的固化动力学方程。所建立的固化动力学方程,能同时适用于有无溶剂场合,可根据体系的组成(环氧树脂、固化剂和溶剂)及固化温度预测其凝胶时间,为优化防腐涂料配方及固化工艺提供了理论指导。     

新型污泥吸附材料制备及其对镉、铬吸附行为研究

采用化学活化法,以污水处理厂的剩余污泥为原料,掺杂软锰矿作为造孔剂制备新型污泥吸附材料。研究新型污泥吸附材料对废水中Cd(Ⅱ)、Cr(Ⅲ)的吸附行为。结果表明:新型污泥吸附材料的比表面积比纯污泥吸附材料提高了52.3%。新型吸附材料对Cd(Ⅱ)、Cr(Ⅲ)的吸附容量和吸附能力大小:Cr(Ⅲ)Cd(Ⅱ)。两种金属离子的吸附性能符合二级吸附速率方程,吸附速率:Cd(Ⅱ)Cr(Ⅲ),平衡吸附量:Cd(Ⅱ)Cr(Ⅲ)。对于Cd(Ⅱ),颗粒内扩散过程是该吸附速率的控制步骤,而对于Cr(Ⅲ),颗粒内扩散过程不是吸附速率的控制步骤。     

两种交联氨基淀粉对水中Cu2＋的吸附性能

研究了含C-N键的氨基淀粉（CAS）与含CN键的氨基淀粉（DAS）对重金属离子Cu2＋的吸附性能,包括吸附动力学、吸附等温线和吸附热力学。结果表明CAS比DAS的吸附容量更大,Cu2＋去除率更高;CAS适用的pH为5～7,DAS适用的pH为4～4．5;两者对Cu2＋的吸附均符合拟二级动力学;CAS对Cu2＋等温吸附符合Freundlich型,为非均相表面吸附;DAS吸附则是单层吸附;两种氨基淀粉对Cu2＋的吸附过程均为吸热、熵增、自发的过程。     

枯草芽孢杆菌Dg5041液体发酵生产γ-聚谷氨酸

以枯草芽孢杆菌Dg5041为生产菌,对其摇瓶发酵生产γ–聚谷氨酸(γ-PGA)的工艺进行研究,通过单因素实验和正交实验获得了该菌的优化培养条件。优化的培养基组成为:葡萄糖35 g/L,酵母膏10 g/L,谷氨酸钠40 g/L,MgSO41.0 g/L,K2HPO4 2.0 g/L,MnSO40.5 g/L,pH 7.0,250 mL锥形瓶装液量50 mL。菌种在37℃,120 r/min培养24 h加入5%NaCl后继续培养24 h,γ-PGA产量达到18.54 g/L。研究结果表明,枯草芽孢杆菌Dg5041是一株很有潜力的γ-PGA高产菌。     

Thermal properties and crystallization behavior of bamboo fiber/high‐density polyethylene composites: Nano‐TiO2 effects

In this study, bamboo fiber/high‐density polyethylene (HDPE) composites were prepared, and the effects of nano‐TiO₂ on their thermal properties and crystallization behavior were investigated via thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results show that the addition of nano‐TiO₂ improved the thermal stability and had a dual function in the crystallization behavior of the composites. On one hand, it functioned as a nucleating agent. The addition of 2 wt % nano‐TiO₂ promoted the crystallization, which caused the increase of the crystallization rate and crystallinity degree, as well as the micronization of the crystalline grain. On the other hand, intermolecular hydrogen bonds and covalent bonds were formed between nano‐TiO₂ and the polymer matrix, which hindered the crystallization of the composites. When the content of nano‐TiO₂ was continually increased, the inhibitory effect of the crystallization was gradually enhanced, which resulted in a decrease in the crystallization rate and crystallinity degree of the composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39846.     

Miniemulsion polymerization of fluorinated siloxane‐acrylate latex and the application as waterborne textile finishing agent

Fluorinated siloxane–acrylate polymer latex was synthesized via miniemulsion polymerization, which was carried out by pseudo one‐step method. In the synthesis protocol, the monomers of octamethylclotetrasiloxane (D₄), tetravinyltetramethylcyclotetrasiloxane (D₄^v), methyl methylacrylate, butyl acrylate, N‐methylol acrylamide, and dodecafluoroheptyl methacrylate (DFMA) were first mixed and homogenized into a miniemulsion, which was stabilized by dedecybenzene sulfonic acid. The ring‐opening polymerization of cyclosiloxane was then steadily performed under miniemulsion conditions and followed by the postaddition of radical initiators to initiate the polymerization of acrylate and DFMA monomers. The influences on the emulsion properties by acrylic monomer with different addition protocol were investigated in this work. In addition, the synthesized latexes were characterized by using dynamic laser scattering, transmission electron microscope, differential scanning calorimetry, and Fourier transform infrared spectroscopy. These results indicated that the introduction of D₄^v in the latex can successfully suppress the phase separation between the thermodynamically incompatible components for the formation of uniform hybrid latex particles. The further application of the as‐synthesized latex was investigated as a new kind of waterborne textile finishing agent. Moreover, the influences of the content of D₄^v and DFMA on the finishing properties, especially for the softness, the water repellence, and the antimoisture properties, were systematically studied in this work. With a proper design on the content of the D₄^v and DFMA, stable textile finishing emulsion was prepared, which can endow the fabric both desirable softness and excellent water resistances. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40161.     

Thermal and flammability performance of polypropylene composites containing melamine and melamine phosphate‐modified α‐type zirconium phosphates

In this article, melamine (MA) and melamine phosphate (MP) have been intercalated into α‐type zirconium phosphate (α‐ZrP) interlayer spaces. The structure and thermal properties of the corresponding powders, MA‐ZrP and MP‐ZrP, were ascertained by X‐ray diffraction, Fourier transform infrared spectra, X‐ray photoelectron spectroscopy measurement, and thermogravimetric analyses (TGA). Furthermore, polypropylene (PP) and its intumescent flame retardant (IFR) composites containing the two organically modified α‐ZrP powders using maleic anhydride‐grafted PP (JPP) as compatibilizer were fabricated by melt blending. The results from TGA and cone calorimetry demonstrated that PP/JPP and PP/JPP/IFR composites containing MA‐ZrP and MP‐ZrP exhibited better thermal stability and burning behavior in comparison with their corresponding counterparts, PP/JPP and PP/JPP/IFR, respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40254.     

Effect of Ba Content on the Stress Sensitivity of the Antiferroelectric to Ferroelectric Phase Transition in (Pb,La,Ba,)(Zr,Sn,Ti)O3 Ceramics

The effect of Ba content on the stress sensitivity of the antiferroelectric to ferroelectric phase transition in (Pb_0.94?xLa_0.04Ba_x)[(Zr_0.60Sn_0.40)_0.84Ti_0.16]O₃ ceramics is investigated through monitoring electric field‐induced polarization and longitudinal strain under compressive prestresses. It is found that incorporation of Ba significantly suppresses the stress sensitivity of the phase transition, as manifested by slight decreases under prestresses up to 100 MPa in the maximum polarization (P_m) and longitudinal strain (x_m). The energy storage density is even increased under the mechanical confinement in compositions x = 0.02 and 0.04. X‐ray diffraction, transmission electron microscopy, and dielectric measurements indicate that the suppressed stress sensitivity is associated with the disruption of micrometersized antiferroelectric domains into nanodomains and the transition from antiferroelectric to relaxor behavior.     

Potentiostatically deposited polypyrrole/graphene decorated nano-manganese oxide ternary film for supercapacitors

A simple method based on potentiostatic polymerization was developed for the preparation of ternary manganese oxide-based nanocomposite films. The ternary nanocomposites, which were characterized using x-ray diffraction spectroscopy and x-ray photoelectron spectroscopy, showed that the manganese oxide within the film consisted of MnO₂ and Mn₂O₃. Electrochemical measurements showed that the ternary nanocomposite electrode exhibited high specific capacitance (up to 320.6 F/g), which was attributed to the morphology of a polypyrrole/graphene/manganese-oxide (PPy/GR/MnO_x) ternary nanocomposite. The experimental approach maximized the pseudocapacitive contribution from redox-active manganese oxide (MnO_x) and polypyrrole (PPy), as well as the electrochemical double layer capacitive (EDLC) characteristic from graphene (GR) sheets. Long cyclic measurements indicated that the specific capacitance of the ternary nanocomposite film could retain 93% of its initial value over 1000 charge/discharge cycles, in the potential range of −0.2 to 0.7 V versus silver/silver chloride electrode (Ag/AgCl).