Synthesis,morphology and properties of segmented poly(ether ester amide)s comprising uniform glycine or β-alanine extended bisoxalamide hard segments

Segmented poly(ether ester amide)s comprising glycine or β-alanine extended bisoxalamide hard segments are highly phase separated thermoplastic elastomers with a broad temperature independent rubber plateau. These materials with molecular weights, M_n, exceeding 30 × 10³ g mol^?1 are conveniently prepared by polycondensation of preformed bisester–bisoxalamides and commercially available PTHF diols. FT-IR revealed strongly hydrogen bonded and highly ordered bisoxalamide hard segments with degrees of ordering between 73 and 99%. The morphology consists of fiber-like nano-crystals randomly dispersed in the soft polymer matrix. The micro-structural parameters of the copolymers were addressed by simultaneous small- and wide-angle X-ray scattering. It is shown that the crystals have strictly identical thickness, which is close to the contour length of the hard segment. The long dimension of the crystals is identified with the direction of the hydrogen bonds. The melting transitions of the hard segments are sharp, with temperatures up to 170 °C. The studied polymers have an elastic modulus in the range of 139–170 MPa, a stress at break in the range of 19–31 MPa combined with strains at break of higher than 800%. The segmented copolymer comprising the β-alanine based bisoxalamide hard segment with a spacer of 6 methylene groups has a melting transition of 141 °C which is higher than the melting transition of its glycine analogue of 119 °C. Likewise, the fracture stress increased from 22 to 31 MPa when the glycine ester group in the hard segment was replaced with β-alanine. The improved thermal and mechanical properties of the latter polymers is related to the crystal packing of the β-alanine based hard segments in the copolymer compared to the packing of the hard segments comprising glycine ester groups.     

UHMWPE微粉辐照接枝MAH的研究

采用辐照方法在超高分子量聚乙烯（ＵＨＭＷＰＥ）微粉表面接枝马来酸酐（ＭＡＨ），用水在ＵＨＭＷＰＥ膜上的润湿角作为目标函数，依据试验优化设计和灰色系统控制理论，研究了辐照剂量、微粉的粒度和ＭＡＨ单体的浓度对润湿角的影响。研究结果表明：所考查的三因数对润湿角的影响程度是不同的，影响顺序为：辐照剂量＞ＵＨＭＷＰＥ微粉粒度＞ＭＡＨ浓度。从关联角度看，三因素对润湿角的关联度没有明显的差别，表明在ＵＨＭＷＰＥ微粉辐照接枝的反应过程中，所考查的三因素对接枝反应过程的影响是互相促进、互相影响、互相补充的。由于辐照剂量在ＵＨＭＷＰＥ的接枝反应中是比较重要的因素，因此在接枝反应中要严格控制其辐照剂量，其次注意微粉粒度，适当调整单体加入量。至于交互作用，尚需进一步进行研究探讨。     

衬塑钢管、管件的成型工艺探讨

简述了镀锌钢铁管和玛钢管配件实施内衬塑的特性及应用概况,重点阐述了衬塑方法和注塑模具的特殊设计结构。     

微波消解-电感耦合等离子体质谱法测定水果中多种微量元素含量

本研究建立了微波消解样品,电感耦合等离子体质谱法测定水果中微量元素含量的方法。采用HNO3+H_2O_2+H2O(5/2/2,V/V/V)作为微波消解的酸体系,并利用程序升温控制溶样。在选定的实验条件下,本方法的最低检出限为0.1 ng/g~13.5 ng/g,相对标准偏差为0.98%~3.50%,回收率为96.7%~103.7%,在0.001 mg/L~0.500 mg/L范围内呈良好的线性关系(r≥0.9997),具有操作简单、快速、灵敏度高、抗离子干扰能力强的优点,完全适用于快速准确测定水果中的微量元素。     

顺德区地下水(潜水层)质量评价

近年来,随着地下水污染事件的不断曝光,地下水污染问题越来越受到人们的关注。地下水相对地表水不易受到污染,但地下水一旦被污染,治理就非常困难。本文收集、整理统计了顺德区共计187眼地下水潜水层监测井的监测数据。经分析表明,顺德区地下水潜水层目前主要污染因子为总大肠菌群、高锰酸盐指数、亚硝酸盐、氨氮;监测井水质为较差~极差的占75.9%。从整体来说,顺德区地下水潜水层现状水质偏差,地下水目前受到一定程度的污染。     

整体炉衬镍铁回转窑锚固件的设计与应用

锚固件在不定形耐火材料中起到增强牢固性的作用,所以其使用性能的好坏直接影响着不定形耐火材料的使用效果. 整体炉衬镍铁回转窑使用的锚固件为U型、Y型、V型、双R型或锚固砖. 使用合适的锚固件后炉衬的整体性好,窑体寿命长,产能高,成本低.     

Design and screening of ionic liquids for C2H2/C2H4 separation by COSMO‐RS and experiments

Ionic liquids (ILs) have been proposed as promising solvents for separating C₂H₂ and C₂H₄, but screening an industrially attractive IL with high capacity from numerous available ILs remains challenging. In this work, a rapid screening method based on COSMO‐RS was developed. We also present an efficient strategy to improve the C₂H₂ capacity in ILs together with adequate C₂H₂/C₂H₄ selectivity with the aid of COSMO‐RS. The essence of this strategy is to increase molecular free volume of ILs and simultaneously enhance hydrogen‐bond basicity of anions by introducing flexible and highly asymmetric structures, which is validated by a new class of tetraalkylphosphonium ILs featuring long‐chain carboxylate anions. At 298.1 K and 1 bar, the solubility of C₂H₂ in ILs reaches 0.476 mol/mol IL, very high for a physical absorption, with a selectivity of up to 21.4. The separation performance of tetraalkylphosphonium ILs to the mixture of C₂H₂/C₂H₄ was also evaluated. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2016–2027, 2015     

N-甲基吗啉钨酸盐催化环氧化环辛烯反应研究

合成一种新型N-甲基吗啉钨酸盐[Mor1,n]Na W2O11(n=2,5,8),并考察了在以30%H2O2为氧化剂,乙腈为反应溶剂,[Mor1,2]Na W2O11为催化剂的催化环氧化环辛烯的反应体系中反应溶剂的量、催化剂的量、氧化剂的量和反应温度的变化对产率的影响,最终确定了最佳反应条件:反应温度70℃,环辛烯1 mmol,催化剂量30μmol,H2O2(30%)量2 mmol,乙腈0.5 m L,反应6 h,产率96%。     

有限元法在Φ3 m×10 m滚筒筛开发中的运用

在Φ3 m×10 m滚筒筛设计阶段,利用有限元法校核计算了筛筒的应力和变形。计算结果表明:(1)设计方案可靠、安全;(2)筛板对筛筒的强度、刚度有很大的加强作用。利用此结论,对溧阳项目运行一年后滚筒筛筛筒开裂进行了原因分析,并有针对性的提出整改建议。