一步法多单体反应挤出PP/PA6增容体系研究

采用一步法将接枝单体马来酸酐(MAH)和苯乙烯(St)、引发剂过氧化二异丙苯(DCP)与聚丙烯(PP)、尼龙6(PA6)、乙烯辛烯共聚物(POE)等混匀后在双螺杆挤出机中就地反应增容，详细地讨论了MAH／St／DCP用量和PA6含量对共混体系拉伸性能和冲击性能的影响；通过扫描电镜(SEM)分析了MAH／St／DCP用量及PA6含量对共混物的亚微形态、相界面的影响；通过红外光谱(FTIR)的结果分析对PP／PA6共混物增容反应机理进行了初步探讨。结果表明：一步法添加MAH／St／DCP引起PP／PA6共混体系发生了酰亚胺化反应，生成了Pp—(St—MAH)—PA6接枝共聚物有很好的增容作用；PA6与基体PP的界面非常模糊，分散相的颗粒也变得均匀细小，约0．5μm，大大改善了两相之间的粘结；从而使得PP／PA6共混体系的力学性能有了较大的提高，PA6质量分数在20％，MAH／St／DCP添加1～4份时效果最佳，缺口冲击强度提高2倍左右，拉伸强度、断裂伸长率、无缺口冲击强度也有明显改善。     

The study on the conductivity of styrene-maleic anhydride copolymer electrolytes based on poly(ethylene glycol)400 and LiClO4

Polyelectrolytes, in this study were synthesized from styrene-maleic anhydride (SMA) copolymer, poly(ethylene glycol)400 (PEG400), and lithium perchlorate (LiClO₄). Fourier transform infrared spectroscopy (FTIR), and magic angle spinning (MAS) solid-state NMR were used to monitor the interaction between Li⁺ ions and polymer. The results of FTIR and MAS solid-state NMR indicate the Li⁺ ions are preferentially coordinated to the ether oxygen of PEG. The T_g of the PEG segments in polyelectrolyte increases with LiClO₄ concentration, as determined by differential scanning calorimetry (DSC), indicating that solubility of the Li⁺ ions in the host polymer increases with the PEG content. Impedance spectroscopy (IS) shows that the bulk conductivity of polyelectrolytes and the conductivity behavior obeys the Vogel-Tamman-Fulcher (VTF) equation.     

Na^＋和Ti^4＋对CaO—Al2O3—SiO2系玻璃结构和晶化的影响

使用ＲＡＭＡＮ光谱和ＤＴＡ方法研究了含少量Ｎａ＋和Ｔｉ４＋的ＣａＯ－Ａｌ２Ｏ３－ＳｉＯ２系玻璃，发现在纯ＣＡＳ系玻璃（Ｃａ／Ａｌ≥１／２，Ａｌ／Ｓｉ≤１）中，Ａｌ３＋仅有一部分进入玻璃网络，少量Ｎａ＋的引入，有助于Ａｌ３＋进一步进入玻璃网络中，Ｎａ＋起了间接补强玻璃网络的作用，Ｎａ＋和Ｃａ２＋离子对Ａｌ３＋进入玻璃网络结构程度的影响可认为是Ｎａ＋和Ｃａ２＋离子分别以［ＡｌＯ４］Ｎａ和［ＡｌＯ４］Ｃａ［ＡｌＯ４］基团的形式进入玻璃网络中，由于结合几率和体积效应，使［ＡｌＯ４］Ｎａ较［ＡｌＯ４］Ｃａ［ＡｌＯ４］更易进入玻璃网络中。Ｔｉ４＋以［ＴｉＯ４］的形式进入玻璃网络，它对Ａｌ３＋是否能进入玻璃网络无明显影响。Ｎａ＋和Ｔｉ４＋的单独引入，均能使玻璃网络的聚合程度增强，析晶活化能提高；而当Ｎａ＋和Ｔｉ４＋同时引入时，玻璃网络聚合程度和纯ＣＡＳ系玻璃相差不大，析晶活化能有所降低。少量Ｎａ＋的引入，不会影响析出主晶相的种类和数量，而Ｔｉ４＋的引入，则会影响到所析出主晶相的种类和数量。     

SO_4~(2-)/ZrO_2-Al_2O_3催化合成脂肪酸季戊四醇酯的研究

以脂肪酸和季戊四醇为原料,三甲苯为带水剂,SO42-/ZrO2-Al2O3固体超强酸催化,合成脂肪酸季戊四醇酯。实验结果表明,控制酯化温度(180～200)℃、醇酸物质的量比为1∶5.6、催化剂加入量为原料总量的0.9%和反应时间为4h时,可获得最佳反应结果,酯化率达99.88%。IR谱表明,产品中羟基吸收峰基本消失,证明酯化反应较充分和完全。     

Polymer pendant ligand chemistry, 4. Recovery of precious metal ions from strongly acidic solution with a polymer-supported o-phenylenediamine hydrochloride ligand

We report on the synthesis and reactivity of a polymer-supported o-phenylenediamine hydrochloride ligand, PS-PDHC, using macroporous 6% crosslinked polystyrene-divinylbenzene beads. The PS-PDHC ligand was found to be highly selective to AuCl₄⁻ ions in strongly acidic solutions in the presence of other precious metal ions, PdCl₄²⁻, PtCl₄²⁻, RhCl₆³⁻, and RuCl₅²⁻ (selectivity values: 2.5, Au/Pd; 7.5, Au/Pt; 7, Au/Rh; 2.2, Au/Ru) as well as other transition metal ions, Fe ³⁺, Cr³⁺, CU²⁺, Nit+, and Mn²⁺. The sorption capacity, selectivity, kinetics of removal and recovery, and solution isotherms have been determined for AuCl₄⁻ ions in competition with the above-mentioned metal ions. The relative ease of formation of the anionic complex in 0.5 M HCI, AuCl₄⁻ was thought to be the primary reason for its selective ability to bind to the PS-PDHC ligand by an anion-exchange mechanism. Therefore, the effect of the HCI concentration on the kinetics of AuCl₄⁻ ion removal from solution was also investigated to clearly show that raising the pH from 0 to 5 caused a dramatic decrease in rate. The AuCl₄⁻ ion can be recovered quantitatively from the PS-PDHC beads using a 5% thiourea solution in 0.1 M HCl, allowing the polymer-supported ligand to be reused.     

Heterogeneous photocatalytic reduction of Fe(VI) in UV-irradiated titania suspensions: effect of ammonia

Results of the heterogeneous photocatalytic reduction of Fe(VI) in UV-irradiated TiO₂ suspensions in the presence of ammonia are presented. The initial rate of Fe(VI) reduction, R, may be expressed as R = k _Fe(VI)[Fe(VI)]^1.25 where k _Fe(VI) = a[Ammonia]+b), a = 6.0 × 10³ μm ^0.25 s and b = 4.1 × 10⁶ μm ^−1.25s⁻¹. The rate constant, k _Fe(VI), increases with the ammonia concentration. The photocatalytic oxidation of ammonia is enhanced in the presence of Fe(VI). A mechanism involving Fe(V) as a reactive intermediate is presented which explains the faster photocatalytic oxidation of ammonia in the presence of Fe(VI).     

SO_4~(2-)/ZrO_2超强酸催化合成乙酸异戊酯的研究

在催化剂SO2 -4/ZrO2 存在下 ,研究了乙酸异戊酯的合成反应 ,考察了反应物用量、反应时间、催化剂用量对酯化反应的影响。最佳工艺条件 :催化剂用量 1 5g、醇酸摩尔比为 1∶2 5、反应时间 1 5h ,收率达 73 5 %。     

截面形状对聚酰胺6/石墨烯复合纤维性能的影响

通过母粒共混熔融纺丝法制备了圆形、三角形和十字形截面的聚酰胺6/石墨烯复合纤维。采用光学显微镜观察了纤维的截面形貌并计算其异形度,采用负离子测试仪、远红外发射率测试仪、恒温恒湿干燥箱表征了不同截面纤维的负离子释放性能、远红外辐射性能和纤维吸湿及其干燥速度。研究表明:圆形、三角形和十字形截面纤维的异形度分别达到6.31%、34.80%和58.29%。相对而言,异形度增大,会明显影响纤维的负离子释放浓度、吸湿速度及干燥速度,其中十字形截面纤维的负离子释放浓度最高达到1 820个/cm~3;另一方面,异形度的变化不会对纤维远红外辐射能力产生明显的影响,其远红外发射率在0.90～0.93,远红外辐射温升约为1.70℃。