Effect of compatibilizers on the crystallization kinetics of cellulose-filled high density polyethylene

High density polyethylene (HDPE) is a ubiquitous material with versatile properties. It is produced and used in greater volume than any other thermoplastic. HDPE is often filled with a variety of materials for various applications. Glass fiber and wood flour are two common fillers for HDPE. This study investigated microcrystalline cellulose (MCC) as a filler in HDPE. The use of compatibilizers, or coupling agents, was investigated as a means of improving the dispersion of the cellulose filler in the HDPE matrix and the mechanical properties of the resulting composites. One compatibilizer was shown to improve the strength of the resulting composite. The stiffness was unaffected, as expected. Thermal properties were measured by means of differential scanning calorimetry. Analysis of the crystallization kinetics indicated that the Avrami coefficient was altered by the filler and was also modified by the presence of the compatibilizer. The presence of cellulose and/or compatibilizer increased the matrix degree of crystallinity. The two compatibilizers studied did not behave similarly and may have different mechanisms of compatibilization.     

Investigation of interfacial adhesion in nylon-6 fibre/NBR composites through restricted equilibrium swelling technique

Short nylon-6 fibre reinforced acrylonitrile butadiene rubber (NBR) composites were prepared and the interfacial adhesion was evaluated by the restricted solvent swelling technique. The solvents used were N,N-dimethyl formamide (DMF), dimethyl sulphoxide (DMSO) and acetonitrile. As the fibre content increased, the solvent uptake decreased, which has been attributed to the increased hindrance to solvent penetration due to better fibre–rubber interaction. It was observed that the ratio of change in volume fraction of rubber before and after swelling to the volume fraction of rubber before swelling (V ₀ – V _r/V ₀) was lower for a bonding agent added composite, compared to the unbonded one. Anisotropic swelling studies were carried out to analyze the extent of fibre alignment and fibre–matrix interaction. It was seen that in strongly bonded composites, the swelling mainly took place in the thickness direction. The rubber–fibre interaction has also been examined by the Lorenz–Parks and Kraus equations.     

脂肪酸萃取锡精矿中微量稀土元素的方法研究

从锡矿石中测定伴生微量元素,主要采用加碘化铵分离锡.卢国仪等人,在两次氢氧化钠熔矿时加入碘化铵灼烧除锡后,完成微量锆的比色测定.由于锡精矿中含锡量高达50％以上,又极易水解,对于微量稀土元素的偶氮肿Ⅲ比色测定有严重干扰.脂肪酸萃取稀土元素已有报道.但用来萃取锡精矿中微量稀土元素未见报道. 本文指出,脂肪酸用来萃取锡矿石中微量稀土元素有很高的选择性,不因多次分离而损失,只需一次萃取分离后,直接进行比色测定.本文研究了在pH4.0～5.5的饱和硝酸     

几种新的4-酰基吡唑酮类螯合剂的合成

Eight new 1-phenyl-3-methyl-4-acyl-pyrazolones (1a-f, 2a, b) have been synthesized in good yield by reacting the corresponding acid halide with 1-phenyl-3-methyl-pyrazolone in dioxane in the presence of suspended Ca(OH)2 or Ba(OH)2, the products were identified by elemental analyses, IR, UV and 1H NMR spectra. Preliminary experiments indicate that all of their extraction efficiency for (UO2)2+ in chloroform-water are better than that of PMBP. The relative efficiency is found to be of the following order: 1b, 1d, 1f>1a, 1e>1c, 2a>2b>PMBP.     

锂的新萃取体系研究

本文报道由偶氮类螯合剂, 季铵盐及邻二氯苯所组成的一类新萃取体系的萃锂性能。讨论了该体系的萃锂反应机理、萃取热力学及萃合物结构。实验结果表明, 新体系具有良好的萃锂性能及很大的锂钠分离系数(β~Li~/~Na)。     

N,N-双-羧 甲基氨基乙酰蛋氨酸的合成及其与铟(III)离子螯合行为的研究

The synthesis of N, N-bis-carboxymethylaminoacetomethionine was described. The acid dissociation constants and the formation constants of its indium (III) chelates at 25`C and \m\=0.1(KNO3) were determined (pka1=2.452, pka2=3.320, pka3=6.799; log KInL=8.90, log KInLi=6.47, log βInLi=15.37) by pH titration method. The hydrolysis constant of the chelate at 30`C was also given. The optimal pH for the formation of normal chelate was calculated to be about 4.8. In addition, the chelate species and coordinated atoms of the ligand were briefly discussed.     

导向有机合成的金属有机化学研究初探

总结了麻生明自1997年回国后在国家自然科学基金委、科技部、中国科学院、上海市科委的共同资助下开展的一些研究工作：(1)联烯化学;(2)偶联反应的区域选择性研究-1-芳基-1-炔烃的单锂化反应;(3)多中心反应-1,1-二溴-1-烯烃的氧化加成反应,α-脱卤钯化反应和分子内双环钯碳化反应。     

STYRENE POLYMERIZATION MEDIATED BY CYCLIC TRITHIOCARBONATE AS RAFT AGENT

The novel cyclic trithiocarbonate was synthesized by dialkylation of trithiocarbonate anion with 2,2＇- bis（bromomethyl）biphenyl in a two-phase system using an onium salt as a phase-transfer agent. Styrene polymerization was carried out in the presence of cyclic trithiocarbonate （CTTC）. CTTC undergoes ring opening-polymerization and the incorporated trithiocarbonate moiety derived from CTTC performs as the reversible addition-fragmentation chain transfer （RAFT） agent. Through this mechanism, multiblock polys-tyrenes containing various narrow polydispersity blocks can be prepared.     

稀土配合物研究 II: 1,6-双(1'-苯基-3'-甲基-5'-氧代吡唑-4'-基)-1,6-己二酮与钐(III)、铕(III)、铽(III)、镝(III)固体配合物的合成及性质研究

本文合成了1,6-双(1'-苯基-3'-甲基-5'-氧代吡唑-4'-基)-1,6-己二酮与Sm(III),Eu(III), Tb(III), Dy(III)的固体配合物, 并对他们的某些性质进行了研究.