Radiation-induced crystallization of polyamide-1010 containing heterogeneous nuclei

Radiation-induced crystallization of polyamide-1010 (PA1010) or nylon-1010 containing heterogeneous nuclei (neodymium oxide, Nd2O3) is discussed in this paper by Wide Angle X-ray Diffraction (WAXD) and Differential Scanning Calorimetry (DSC). The results show that at low dosage the crystallinities of the irradiated specimens increase, while crystallite size (L(hkl)) decreases, indicating that some new crystallites are produced in the course of irradiation. The new centers were brought about in the fold surface of the lamellae. Copyright (C) 1997 Elsevier Science Ltd

PVC-尼龙6树脂应用于天然水中痕量金的价态分析

在王水介质中，ＰＶＣ－尼龙６树脂定量吸附Ａｕ（Ⅲ），而Ａｕ（Ⅰ）基本上不吸附。当存在碘离子时，Ａｕ（Ⅲ）和Ａｕ（Ⅰ）均能形成碘的络阴离子而被树脂定量吸附，从而可分别测出总金和Ａｕ（Ⅲ）的含量并计算出Ａｕ（Ⅰ）的含量。方法的检测限为１．６×１０－１１ｇ／Ｌ，样品加标回收率在８０％以上。为天然水中痕量金的价态分析提供了一个令人满意的方法。

4-羟基偶氮苯与6-氯-5,12-萘并萘醌反应产物的NMR分析

无水碳酸钾存在下6-氯-5,12-萘并萘醌与4-羟基偶氮苯在干燥DMF中反应的主要产物在某些反应条件下不是6[4-(苯基偶氮基)苯氧基]-5,12-萘并萘醌(1)。该未知反应产物2经核磁共振方法研究证实是6-(N,N-二甲氨基)-5,12-萘并萘醌。本文对化合物2的~1H-和~(13)C化学位移、偶合信息和结构作了详细归属,并推测其反应进程,实验结果表明,化合物2是由化合物1与溶剂DMF反应生成。

组成对PA1010/6共聚物熔融行为的影响

用ＤＳＣ研究了ＰＡ１０１０／６共聚物初生态及次生态样品的熔融行为，发现初生态样品的高温熔融峰（Ｔ１）和低温熔融峰（Ｔ２）对组成有不同的依赖关系；首次发现ＰＡ１０１０／６共聚物次生态的冷结晶现象，并讨论了冷结晶温度（ＴＣ）、冷结晶时间（ｔｃ）与组成的关系.

Exploration of post radiation effects on polyamide-1010

Irradiated polyamide-1010 (PA1010) with and without heat treatment after gamma-ray irradiation was compared by wide angle x-ray diffraction (WAXD), differential scanning calorimeter (DSC) and the determination of gel fractions. The results indicate that post radiation effects due to post radiation crosslinking and scissions affect physical properties. Post radiation effects restrain the formation and perfection of the planes (010), and make the crystals imperfect. Post radiation effects change the crystalline structures of polyamide-1010.

Activation of a ring methyl substituent in pentamethylcyclopentadienyl rhenium(V) compounds: Synthesis and characterization of the 1,2,3,4-tetramethyl-5,6-dihydrofulvene-5,6-dithiolato complex [ReO{(S)(SCH2)C(5)Me(4)}(C(5)Me(5))]

Reaction of the half-sandwich rhenium(v) complexes [Re-Cl-4(C(5)Me(5))] or [Re(O)Cl-2(C(5)Me(5))] with H2S in chloroform in the presence of pyridine leads to the chiral dithiolato complex [ReO((S)(SCH2)C(5)Me(4))(C(5)Me(5))] 1.

Properties of ethylene-propylene copolymer/PA-1010 blends using ethylene-propylene copolymer-graft-acrylic acid as a compatibilizing agent

The modification of ethylene-propylene copolymer (EP) has been accomplished by radical EP-graft-acrylic acid (EP-g-AA) has been used to obtain ternary PA/EP/EP-g-AA blends by melt mixing. Different blend morphologies were observed by scanning electron microscopy; the domain size of the EP-dispersed phase in the polyamide 1010 matrix of compatibilized blends decreased compared with that of uncompatibilized blends. It is found that EP-g-AA used as the third component has a profound effect on the mechanical properties of the resulting blends. This behavior has been attributed to serious chemical interactions taking place between the two components. Thermal analysis shows that some thermal properties of PA in compatibilized PA/EP/EP-g-AA changed because of chemical reactions taken place during the blending process. Wide angle x-ray diffraction measurements also confirmed this result. (C) 1996 John Wiley & Sons, Inc.

Studies on morphology and crystallization of polypropylene/polyamide 12 blends

Scanning electron microscopy (SEM) and an image analyser are used to study morphologies of the fractured surface, etched by hot phenol, of polypropylene/maleated polypropylene/polyamide 12 PP/PP-MA/PA12) = 65/10/25 blend and PP-MA/PA12 = 75/25 blend. The particle dimension and its distribution of PA12 dispersed phase in these blends are much lower and narrower than that of the PP/PA12. blends. Especially, most of the particles in the PP-MA/PA12 = 75/25 blend are smaller than 0.1 mu m. The effect of the morphology of PP/PA12 blends on their crystallization behaviour is studied using differential scanning calorimetry and SEM. PA12 dispersed phase coarsens during annealing in the PP/PP-MA/PA12 = 65/10/25 blend. The mechanism of coarsening of the PA12 dispersed phase is a coalescence process. The intense mixing between the PP component and the PA12 component through reaction of PP-MA and PA12 leads to a change of dynamic mechanical behaviour of the components. A separation method is used to separate the polyolefin parts (precipitated from hot phenol), from PA12 parts (hot phenol filtrate). Of PP/PP-MA/PA12 = 65/10/25 blend, infra-red measurements and elementary analysis show that the precipitate has a lower PA12 content than the feed, whereas the filtrate has a higher PA12 content. From PP-MA/PA12 = 75/25 blend, PA12 contents in the precipitate and the filtrate are the same as in the feed. This implies that all PA12 has reacted with all PP-MA in the latter case while not in the former case. Using the method of interface exposure, interfacial reaction of PP-MA with PA12 is studied by X-ray photoelectron spectrometry (X.p.s.). Copyright (C) 1996 Elsevier Science Ltd.

Truly chlorine-resistant polyamide reverse osmosis composite membrane

Truly chlorine-resistant polyamide reverse osmosis composite membranes were prepared by cross-linking the interface of the composite membrane. Such membranes possessed chlorine resistance one order of magnitude more than those of the commercially used polyamide composite membranes. The effect of the degree of cross-linking on chlorine resistance was also described. (C) 1996 John Wiley & Sons, Inc.

Isothermal crystallization studies on neodymium oxide filled nylon 6

Melt mixing of nylon 8 with neodymium oxide particles was carried out with a single-screw extruder. The crystal behaviors of plain nylon 6 and the neodymium oxide filled nylon 6 mixture were studied by means of isothermal crystallization kinetic analysis. Isothermal crystallization thermograms obtained by differential scanning calorimetry (DSC) were analyzed based on the Avrami equation. The neodymium oxide particles acted as a nucleating agent in the mixture. The overall rate of di-isothermal crystallization of the neodymium oxide filled nylon 6 mixture is higher than that of plain nylon 6. The mechanism and modes of plain nylon 6 were the same as those of neodymium oxide filled PA6 mixture.

Influence of the fold surface of the lamellae on radiation effects - Research on irradiated polyamide-1010 containing heterogeneous nuclei

Irradiated polyamide-1010 (PA1010) and PA1010 containing 0.5% (wt) heterogeneous nuclei were studied by ESR, WAXD, DSC and the determination of gel fractions. The fold surface of the lamellae plays an important role in the effects of radiation on crystalline PA1010. The results show that the direct radiation effects on both samples vary, while after being heated to 220 degrees C, the final radiation effects are identical, regardless of the difference in the amount of the fold surface of the lamellae. The post-radiation effects result predominantly from the fold surface.

Electrochemical study of isopoly- and heteropoly-oxometallates film modified microelectrodes .6. Preparation and redox properties of 12-molybdophosphoric acid and 12-molybdosilicic acid modified carbon fiber microelectrodes

The redox behaviours of 12-molybdophosphoric acid (12-MPA) and 12-molybdosilicic acid (12-MSA) in aqueous acid media are characterized at the carbon fiber (CF) microelectrode. The preparation of CF microelectrode modified with 12-MPA or 12-MSA monolayer and the oxidation-reduction properties of the modified electrode in aqueous acid media or 50% (v/v) water-organic media containing some inorganic acids are studied by cyclic voltammetry. 12-MPA or 12-MSA monolayer modified CF microelectrode with high stability and redox reversibility in aqueous acidic media can be prepared by simple dip coating. The cyclic voltammograms of 12-MPA and 12-MSA and their modified CF microelectrodes in aqueous acid solution exhibit three two-electron reversible waves with the same half-wave potentials, which defines that the species adsorbed on the CF electrode surface are 12-MPA and 12-MSA themselves. The acidity of electrolyte solution, the organic solvents in the electrolyte solution, and the scanning potential range strongly influence on the redox behaviours and stability of 12-MPA or 12-MSA monolayer modified electrodes. On the other hand, the catalytic effects of the 12-MPA and 12-MSA and chlorate anions in aqueous acidic solution on the electrode reaction processes of 12-MPA or 12-MSA are described.

WAXD and SAXS study on gamma-radiation damage to polyamide-1010 crystal structure

In the present work we attempt to settle the controversy on the district wherein the radiation induced reaction preferentially occurs through examining the structural changes of the irradiated polyamide-1010 specimens on both the crystallographic and the supermolecular level by using WAXD and SAXS techniques. Experimental results indicated that the chain crosslinking and scission of the irradiated specimens occur mainly in the amorphous region and on the crystal surface (or interphase), and extend into the inner portion of the crystal with increasing radiation dose.