MMA/纳米TiO_2改性白乳胶的研制

为提高白乳胶的粘接性能和耐水性,采用硅烷偶联剂(KH-570)和甲基丙烯酸甲酯(MMA)对纳米TiO2(nano-TiO2)进行改性;以MMA和改性nano-TiO2为白乳胶的改性剂,比较了不同改性方法对改性白乳胶的固含量、黏度、硬度、粘接强度和耐水性等影响。结果表明:各种改性方法制成的适量改性nano-TiO2,均能改善白乳胶的相关性能;当m(MMA)∶m(等质量的MMA和KH-570共同改性nano-TiO2)∶m(过硫酸钾)=4∶2∶0.1时,改性白乳胶的黏度(15.72 Pa.s)、硬度(2H)、粘接强度(9.6 MPa)和耐水性(20、80℃水中的开胶时间分别为57、39 h)均达到最大值。     

Al2O3包覆LiNi1/3Co1/3Mn1/3O2锂离子电池正极材料

综述了Al2O3包覆LiNi(1/3)Co(1/3)Mn(1/3)O2锂离子电池正极材料的研究现状与进展,并评述了其制备方法和包覆改性;讨论了包覆改善该正极材料性能的机理;提出了这种正极材料的研发过程中的一些问题并对其未来的发展前景作了展望。     

用改性的钕催化体系聚合丁二烯

使用以氧化丙烯甲基铝改性的Nd(OCOR)3-AlH(iso-C4H9)2-C6H4(CCl3)2催化体系聚合丁二烯。研究了聚合的动力学参数及聚丁二烯的分子特性。此种改性催化体系具有高活性,由此合成的聚丁二烯橡胶硫化胶的力学性能可满足工业上的需要。。     

聚阴离子型锂离子电池正极材料Li_3V_2(PO_4)_3的研究进展

与LiFePO4相比,单斜结构的磷酸钒锂(Li3V2(PO4)3)具有更高的Li+扩散系数和更高的放电电压、能量密度和高的比容量,已成为锂离子电池正极材料的研究热点之一。综述了近年来Li3V2(PO4)3的主要合成方法、充放电机理及其掺杂改性的研究现状,并且对Li3V2(PO4)3的发展趋势进行了展望。     

聚醋酸乙烯酯乳液改性的研究

利用甲苯二异氰酸酯（TDI）,Cr(NO3)3和KAl(SO4)2.12H2O等物质对白乳胶进行改性,探讨了交联剂和螯合剂对PVAc改性的最佳工艺条件,实验结果表明改性后的白乳胶有较高的粘接强度和良好的耐沸水性及固化性能。     

Ni2+-Fe3+-CO2-3-LDHs亲油改性及其除油性能研究

尿素作为沉淀剂,采用均相沉淀技术制备了Ni2+-Fe3+-CO2-3-LDHs层状材料.以Ni2+-Fe3+-CO2-3-LDHs作为前驱体,分别与NaCl、十二烷基磺酸钠(CH3(CH2)11SO3Na)进行离子交换反应得到Ni2+-Fe3+-CH3(CH2)11SO-3-LDHs新型吸附剂材料,成功实现了将CH3(CH2)11SO-3负载到Ni2+-Fe3+-LDHs层状材料,对Ni2+-Fe3+-CO2-3-LDHs进行亲油改性,研究表明该改性后的材料为介孔材料,其比表面积为196.2m2/g,平均孔径为18.3nm.利用Ni2+-Fe3+-CH3(CH2)11SO-3-LDHs复合材料对含油污水进行处理,实验表明十二烷基磺酸根离子插层Ni2+-Fe3+-LDHs后的产物增强了LDHs的亲油吸附性能,其饱和吸附量为6.57μL/g.     

锂离子电池正极材料磷酸钒锂的研究进展

Li3V2(PO4)3因具有优异的电化学性能,成为目前倍受关注的锂离子电池正极材料。介绍了单斜结构磷酸钒锂[α-Li3V2(PO4)3]的结构及充放电机理,概述了几种主要的制备Li3V2(PO4)3方法,包括了固相法、溶胶-凝胶法、微波法。同时阐述了几种主要方法用来对Li3V2(PO4)3电化学性能进行改性研究,对该材料的发展前景进行了展望。     

DPDBO/Sb2O3/DMDPB在LDPE阻燃处理中的应用

研究了2,3-二甲基-2,3-苯基丁烷(DMDPB)、三氧化二锑(Sb2O3)和十溴二苯醚(DBDPO)的加入对低密度聚乙烯(LDPE)的拉伸和阻燃性能的影响探讨了DBDPO与Sb2O3加入量的不同给LDPE的拉伸强度、断裂伸长率和阻燃性能带来的差异。同时研究表明少量的DMDPB加入LDPE／Sb2O3／DBDPO体系,即可显著提高断裂伸长率和阻燃性能。     

不同表面改性活性炭吸附Cr(Ⅵ)的研究

研究了不同表面改性对活性炭吸附废水中Cr(Ⅵ)的影响,将活性炭AC0在2 mol.L-1的HNO3、HCl、H2O2溶液中静置12 h并经过马弗炉煅烧后制得改性活性炭AC1、AC2、AC3。分别考察溶液的pH、吸附时间、温度对废水中Cr(Ⅵ)离子去除率的影响,采用滴定法定量检测活性炭表面的离子交换容量。结果表明:活性炭经过HNO3、HCl改性后,其Cr(Ⅵ)的吸附容量和吸附速度均显著改变,AC1、AC2阳离子交换容量分别为2.21、1.66 mmol.g-1,是AC0的1.7倍、1.28倍。活性炭对Cr(Ⅵ)离子的去除率强烈地依赖于溶液的pH,当溶液pH值控制在2.0～3.0时,Cr(Ⅵ)离子的去除率达到99%左右,随后骤然降低,但是AC1、AC2对Cr(Ⅵ)离子的去除率还能保持在一个较高的水准。     

碱木质素羟基化改性的研究

以Fe(OH)3作为催化剂,用过氧化氢对碱木质素进行羟基化,探讨了反应温度、反应时间、m( H2O2)∶m(木质素)、m(Fe(OH)3)∶ m(木质素)对木质素羟基化改性的影响,并对反应机理进行了初步探讨.实验结果表明,羟基化最佳反应条件是:反应温度为60℃、反应时间为60 min,m( H2O2)∶m(木质素)=1.2∶1,m(Fe(OH)3)∶m(木质素)=(1％ ～4％)∶1,此条件下的羟基值约为改性前碱木质素的2倍,羟基化改性比较成功.     

三聚氰胺甲醛树脂改性P(VAC-MMA)乳液的合成

本文报道了P（VAC－MMA）乳液及三聚氰胺甲醛树脂的合成及其共混。考察了乳液粘度、稳定性及其成膜耐水性等。结果表明，所得P（VAC－MMA）乳液的耐水性、防冻性及PH值适应范围较PVAC均聚物乳液均有所改善。而乳液中三聚氰胺树脂的加入可明显增稠，其成膜耐水性较传统乳白胶有明显改善。     

Dehydration of water–alcohol mixtures by vapor permeation through PVA/clay nanocomposite membrane

An organic/inorganic hybrid nanocomposite membrane, poly(vinyl alcohol)/clay (PVAC), was prepared. The morphology of PVAC nanocomposite membranes were characterized using transmission electron microscopy (TEM), X‐ray diffraction (XRD), and atomic force microscopy (AFM). The crystallinity and surface roughness increases with an increasing clay content in the PVAC nanocomposite membrane. Compared with the pure poly(vinyl alcohol) (PVA) membrane, the hybrid nanocomposite membrane (PVAC) shows an improvement in the thermal stability and the prevention of the water‐soluble property. The oxygen permeability and the water‐vapor permeation rate decreases with an increasing clay content (1–3 wt %) in the PVAC nanocomposite membranes. In addition, the effects of the clay content on the vapor‐permeation performance of an aqueous ethanol solution through the PVAC nanocomposite membranes was also investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3632–3638, 2003     

VAC/DMC阳离子无皂乳液改性水泥砂浆研究

利用醋酸乙烯酯／甲基丙烯酰氧乙基三甲基氯化铵（VAC／DMC）阳离子型无皂乳液对水泥砂浆进行了改性研究，并与普通VAC均聚物乳液进行了比较。研究表明，！与普通水泥砂浆相比，VAC/DMC节离子型无皂乳液改性砂浆（聚灰比为0．1时）的抗折强度较普通砂浆够提高77％，其改性效果明显好于普通VAC乳液，表明用阳离子无皂乳液改性水泥性能能够取得良好效果。探讨VAC／DMC对水泥砂浆改性的原因。     

聚合物乳液改性含钛高炉渣免烧砖

用聚苯乙烯乳液、聚乙酸乙烯酯乳液和苯丙乳液等改性含钛高炉渣浆分别得到免烧免蒸砖试样. 考察了影响试样性能的主要因素和改性机理. 结果表明,聚乙酸乙烯酯乳液改性渣浆试样性能较好,苯丙乳液改性效果最好. 当含钛高炉渣为72%(w,下同)、苯丙乳液为10%、添加剂为18%、成型压力为30 MPa、养护时间为7 d时,渣浆试样的抗压强度和抗折强度分别达到37.7和13.9 MPa. 机理探索表明,苯丙乳液中酸根离子与渣浆中金属离子交联生成了金属络合物.     

IR laser-induced modification of poly(vinyl acetate): Elimination of monomer and deposition of polar crosslinked films

IR laser-induced modification of poly(vinyl acetate) (PVAC) was examined through ablative and non-ablative thermal processing of bulk PVAC. Both laser-induced processes differ remarkably from conventional heating of PVAC, which yields acetic acid and non-polar carbonaceous residue. The non-ablative treatment at low-fluence irradiations results in the formation of volatile vinyl acetate and acetone and leaves the remaining irradiated polymer having an almost identical structure. The ablative treatment at high-fluence irradiations yields a multitude of volatile compounds (methane, ethane, vinyl acetate, acetone, acetic acid, benzene, H₂, CO and CO₂) and affords deposition of thin polymeric films that contain reactive conjugated CC bonds and half of the initially present acetate groups. Residual reactivity of the CC bonds leads to polymer crosslinking, substantial decrease in solubility and some increase in thermal stability. The low fluence-induced decomposition stands for the first example of the thermal decomposition of polyvinyls into the monomer and the high-fluence ablative deposition represents a one-step approach to crosslinked (intractable), thermally stable and polar polymeric films from linear-chain polymers with pending functional groups.     

Synthesis of a new “green” sponge via transesterification of dimethyl carbonate with polyvinyl alcohol and foaming approach

In this article, the low toxicity of polyvinyl alcohol (PVA) and dimethyl carbonate (DMC) were used to synthesize polyvinyl alcohol carbonate (PVAC) sponge via a simple transesterification-foaming approach, and the structure and morphology of PVAC sponge were characterized; moreover, the influence of dosage of K₂CO₃, PVA, distilled water and n-pentane on the water retention capacity of PVAC sponge were investigated, and the influence of reaction temperature and reaction time on the water retention capacity of PVAC sponge were also surveyed. Based on those, it was confirmed that 9.00 g PVA and 5.00 mL DMC in the presence of 2.00 g K₂CO₃ and 50.00 mL water could be used to synthesize PVAC polymer at 75?°C and for 2.5 h via the transesterification approach, and PVAC polymer in the presence of 5.00 mL n-pentane could be used to synthesize PVAC sponge at 55?°C and for 10 h via the foaming approach, and PVAC sponge owned the structure of six-membered lactone ring and the polyporous morphology, and the maximal water retention capacity was 21.50 g/g.     

H2SO4和Al2（SO4）3改性中孔分子筛Al-MCM-41及其催化性能

用SO24-物质的量相同的H2SO4和Al2(SO4)3分别对Al-MCM-41进行改性,得到样品SO42-/Al-MCM-41和Al/SO24-/Al-MCM-41。采用X射线多晶衍射(XRD)、红外光谱(FTIR)、N2吸附-脱附和NH3程序升温脱附(NH3-TPD)等测试技术对样品进行表征。分别用H2SO4、MCM-41、Al-MCM-41、SO42-/Al-MCM-41和Al/SO24-/Al-MCM-41催化合成丙酸香叶酯,比较了它们的催化性能。结果表明,H2SO4和Al2(SO4)3改性对Al-MCM-41中孔分子筛结构影响不明显,都可提高其酸性,改性后中孔分子筛的骨架仍保持着六方介孔结构,孔径、孔容和比表面积有所降低,但用Al2(SO4)3改性的分子筛酸性和催化性能更强;SO42-/Al-MCM-41的酸催化活性主要源于SO42-与分子筛表面硅羟基作用形成的双齿螯合配位结构,而Al/SO42-/Al-MCM-41的酸催化活性一方面来自SO24-与分子筛表面硅羟基作用形成的双齿螯合配位结构,另一方面,也来自与分子筛骨架接枝的铝,使其产生了更多的Brnsted酸中心。     

Study of synergistic influence of l-cysteine on polyvinyl alcohol – Taguchi method: continuous electrochemical monitoring of corrosion inhibition of mild steel by poly(vinyl alcohol-cysteine)

Parametric optimization for better synergism between polyvinyl alcohol (PVA) and l-cysteine was optimized using Taguchi design, a statistical approach. The corrosion inhibition property of poly(vinyl alcohol-cysteine) (PVAC) on mild steel corrosion was continuously monitored using electrochemical techniques such as polarization and impedance methods. Continuous monitoring of the system reveals the formation of stable film on the metal surface. Temperature effect on the inhibition properties of PVAC was studied using electrochemical measurements. Calculated kinetic and thermodynamic parameters supported the spontaneous adsorption of PVAC. Atomic force microscopic and laser profiler analysis confirmed the adsorption of PVAC on mild steel surface. Theoretical calculations using Hyperchem 7.0 proved the better corrosion mitigation properties of PVAC compared to PVA.     

3-异烷氧基噻吩的合成

以CuB r为催化剂,NMP为溶剂,在110℃下,3-溴噻吩与过量的甲醇钠反应2.5 h生成3-甲氧基噻吩,产率为82%。再以无水NaHSO4为催化剂,在108~115℃下,3-甲氧基噻吩分别与异丁醇、异戊醇、异辛醇发生取代反应合成了3-(2-甲基丙氧基)噻吩、3-(3-甲基丁氧基)噻吩、3-(2-乙基己氧基)噻吩,反应时间分别为:3、3.5、4h,收率分别为72%、67%、63%。这些化合物结构都通过IR、1HNMR和MS进行了表征,并对其进行了初步香味评价,结果表明,它们都具有基本肉香味的特征。     

Anticorrosive coating based on poly(vinyl acetate) formed by electropolymerization on the copper surface

The poly(vinyl acetate) (PVAC) film was obtained by electropolymerization on the copper electrode using cyclic voltammetry performed in mixed electrolyte based on water/ethyl alcohol/acetic acid containing vinyl acetate (VAc) and benzoyl peroxide as polymerization initiator. The coatings were characterized by optical microscopy, scanning electron microscopy (SEM) and infrared (IR) spectroscopy. The corrosion was induced in hydrochloric acid solution using potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). The microscopic and SEM images revealed the PVAC coating formation and IR spectroscopy confirmed that it exhibits the same characteristic bands as a standard PVAC sample. From the potentiodynamic polarization, the PVAC protective performance of 78% was computed. The EIS measurements showed the occurrence of the surface adsorbed layer with a higher impedance response to the frequency and a phase angle maximum shifted to lower values than those of uncoated samples. In addition, the VAc electropolymerization mechanism was discussed and the PVAC adsorption mechanism on the copper surface was proposed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47320.