Preparation and Characterization of PET/LDH or Clay Nanocomposites through the Microcompounding Process

Thermally stable modifier were used to modify clay or lithium aluminum layered double hydroxides (LiAl LDH) nanoparticles for preparation of poly (ethylene terephthalate)/clay or LiAl LDH nanocomposites. The effect of modify agent, studied by microcompouding process. The PET nanocomposites which were made by twin‐screw microcompounder dispersion morphology of inorganic layered materials in nanocomposites could be explained by wide‐angle X‐ray diffraction (WXRD), and transmission electron microscopy (TEM). Nanocomposite also formed the better mechanical, UV resistance, and gas barrier properties. Optical properties and crystallization behaviour of these new types of nanocomposites are investigated in this paper.     

聚酰亚胺无机纳米杂化材料

聚酰亚胺(PI)作为一种功能材料，具有良好的介电性、优良力学性能，已被广泛应用于航空航天及微电子领域，但其明显的吸水性和热膨胀性限制了其在高温和精密状态下的应用。无机纳米材料具有很低的热膨胀系数和较低的吸水性，非常适合于对PI的改性。本文阐述了PI纳米杂化材料的制备方法。概要介绍了PI纳米杂化材料的类型、特点、性能及应用领域，并对这类材料的发展前景进行了综述。     

天然-合成高分子生物杂化材料在生物医学领域中的应用

综述了天然—合成高分子生物杂化材料在生物医学领域中的应用，并分析了它作为组织工程基质和药物载体的优点，指出生物杂化材料是生物医用材料的发展趋势。     

Layered double hydroxides for ultrathin hybrid film preparation using layer-by-layer and spin coating methods

In our work, the synthesis and the structural properties of various layered double hydroxides (LDHs) were investigated. LDHs were prepared from metal salts with sodium hydroxide in aqueous medium at various molar ratios. Nitrate salts of, Mg²⁺, Ca²⁺, Co²⁺, Al³⁺ and acetate salt of Zn²⁺ were applied as precursors. The concentrations of LDH suspensions were in the range of 0.1–1 g/100 ml. The particle size and zeta-potential of LDH particles were measured by dynamic light scattering (DLS). The structure properties of LDHs were analyzed by several methods, namely XRD, UV-vis spectroscopy and AFM. We used the layer-by-layer dipping immersion technique and the spin coating method for the preparation of multilayer films from LDHs on glass surfaces. The cleaned glass surface has a negative surface charge, which is compensated by the positively charged LDH particles. Different negatively charged binders poly(sodium 4-styrenesulfonate), (PSS); poly(acryl-acid), (PAA) were utilized for the preparation of layer-by-layer films. Layer thickness was calculated from absorbance measurements by spectrophotometry and mass determination of the glass surface. Typical film thicknesses were in the range of 19–70 nm/layer and 6–40 μg/cm²/layer depending on the type of LDH and preparation technique. After n = 20 immersion cycles, maximal layer thickness was 1405 nm for 20 layers of 2:1 ZnAl–LDH/PSS film. The film preparation methods tested were compared and it was established that the films obtained by the layer-by-layer method are more stable but thicker than those prepared using the spin coating method.     

Preparation and Characterisation of Thermoplastic Starches from Cassava Starch,Cassava Root and Cassava Bagasse

Summary: Thermoplastic starches (TPS) based on cassava starch have been produced by extrusion at 120 °C, using glycerol as plasticizer. Three forms of cassava starch were employed, viz: cassava root (CR), cassava bagasse (CB) and purified cassava starch (PCS). The main differences between these are the presence of sugars and a few fibres in CR and high fibre concentration in CB. Conditions of processing and characteristics such as amylose and fibre content, crystallinity, water absorption and mechanical behaviour in the tension x deformation test were evaluated. The results demonstrated that the PCS and CR had amylose contents consistent with literature values (14–18%) and that CB is a material constituted mainly by amylopectin. It was found that fibres in high proportions (as in the bagasse) can confer reinforcement properties and are thus able to generate natural composites of TPS with cellulose fibre. The sugars naturally found in the root reduce the elongation of the TPS under tension. The PCS and CR TPS were stable with respect to indices of crystallinity after processing; and during a period of 90 d in a relative humidity of 53%, while the CB TPS tended to vary its crystallinity, probably because its amylose chain had low degree of polymerization.     

聚合物/粘土纳米复合材料中的粘土有机化

回顾了聚合物/粘土纳米复合材料中所用粘土的有机化方法与有机粘土的热稳定性,及其对复合材料性能的影响,指出在聚合物/粘土复合材料中粘土片层间距的变化同样有可能受到层间插层剂构象变化的影响、聚合物/粘土纳米材料的长期热氧稳定性与热失重结果可能不一致。     

微波辐射对淀粉结构及性质的影响

简单地介绍了微波对淀粉的辐射作用,并综述了微波辐射对淀粉形态结构和结晶结构以及淀粉凝胶化性质、热性质等影响的国内外研究进展,如微波辐射可改变淀粉颗粒形状、结晶结构及其结晶度.微波辐射时间及辐射能等技术参数能够改变淀粉的凝胶化性质,而淀粉的含水量也是重要的影响因素.淀粉的溶解性、润胀性和吸水性都会因微波辐射而较原淀粉下降.     

环氧/粘土纳米复合材料的形成机理与性能

粘土／聚合物纳米复合材料由于具有优良的物理力学性能和特殊功能而倍受关注。实验证明,粘土也很容易被环氧树脂插层,并在固化过程中剥离,得到纳米复合材料。本文重点综述了粘土／环氧纳米复合材料的形成机理,结构形态和力学性能,并对该类材料的应用前景进行了展望。     

粘土中金属组分对粘土胶热降解的影响

天然橡胶;粘土中金属组分对粘土胶热降解的影响     

木薯淀粉磷酸单酯的性质及结构

木薯淀粉磷酸单酯的性质及结构;木薯淀粉磷酸单酯;理化性质;结构表征     

Preparation of Starch Succinate WITH INTERMEDIATE DS BY AQUEOUS SLURRY REACTION

Modification of starch by chemical derivatization has been widely studied since early 1950s. The formation of starch ester such as acetate and propionate imparts starch water resistance. In contrast, the introduction of carboxylates onto starch increases the hydrophilicity of starch. One example is carboxymethyl starch (CMC), which has been widely used in several industry areas. Succinic anhydride reacts with starch to form starch succinates. Since starch succinates are polyanions, they off…     

Optical and dielectric characteristics of photochromic hybrid sol-gel materials

Photochromic silica based organic-inorganic hybrid materials containing covalently linked cyanoazobenzene chromophores were investigated by optical and dielectric spectroscopy. These materials, obtained via sol-gel process, were deposited onto glass substrates by spin coating technique to achieve thin transparent films. To investigate photoinduced alignment, the UV-Vis absorption spectra of the sol-gel films were recorded under illumination with linearly polarized blue light. Dielectric relaxation spectroscopy revealed a variety of relaxation processes: the α-process related to the dynamic glass transition temperature located around 150°C, and an Arrhenius-type β-relaxation (activation energy 58–60 kJ/mol) that was assigned to orientational fluctuations involving the azobenzene group. The correspondence between dielectric and photochemical behavior was discussed.     

High Solids Content,Soap‐Free,Film‐Forming Latexes Stabilized by Laponite Clay Platelets

High solids content film‐forming poly[styrene‐co‐(n‐butyl acrylate)] [poly(Sty‐co‐BuA)] latexes armored with Laponite clay platelets have been synthesized by soap‐free emulsion copolymerization of styrene and n‐butyl acrylate. The polymerizations were performed in batch in the presence of Laponite and a methyl ether acrylate‐terminated poly(ethylene glycol) macromonomer in order to promote polymer/clay association. The overall polymerization kinetics showed a pronounced effect of clay on nucleation and stabilization of the latex particles. Cryo‐transmission electron microscopy observation confirmed the armored morphology and indicated that the majority of Laponite platelets were located at the particle surface. The resulting nanostructured films displayed enhanced mechanical properties.

     

Sugar-anionic clay composite materials: intercalation of pentoses in layered double hydroxide

The intercalation of non-ionized guest pentoses (ribose and 2-deoxyribose) into the Mg-Al and Zn-Al layered double hydroxides (LDHs) was carried out at 298 K by the calcination-rehydration reaction using the Mg-Al and Zn-Al oxide precursors calcined at 773 K. The resulting solid products reconstructed the LDH structure with incorporating pentoses, and the maximum amount of ribose intercalated by the Mg-Al oxide precursor was approximately 20 times that by the Zn-Al oxide precursor. The ribose/Mg-Al LDH was observed to have the expanded LDH structure with a broad (003) spacing of 0.85 nm. As the thickness of the LDH hydroxide basal layer is 0.48 nm, the interlayer distance of the ribose/Mg-Al LDH is 0.37 nm. This value corresponds to molecular size of ribose in thickness (0.36 nm), supporting that ribose is horizontally oriented in the interlayer space of LDH. The maximum amount of ribose intercalated by the Mg-Al oxide precursor was approximately 5 times that of 2-deoxyribose. Ribose is substituted only by the hydroxyl group at C-2 position for 2-deoxyribose. Therefore, the number of hydroxyl group of sugar is essentially important for the intercalation of sugar molecule into the LDH, suggesting that the intercalation behavior of sugar for the LDH was greatly influenced by hydrogen bond between hydroxyl group of the intercalated pentose and the LDH hydroxide basal layers.     

Synthetic musk fragrances in environmental Standard Reference Materials

Synthetic musk fragrances have been measured in water, air, sediments, sewage sludge, and biota worldwide. As the study of the environmental fate and impacts of these compounds progresses, the need for Standard Reference Materials (SRMs) for these compounds to facilitate analytical method improvement and interlaboratory comparisons becomes increasingly important. The National Institute of Standards and Technology (NIST) issues environmental matrix SRMs with certified concentrations for a variety of persistent organic pollutants including polycyclic aromatic hydrocarbons (PAHs), chlorinated pesticides, and polychlorinated biphenyl congeners (PCBs). Until now synthetic musk fragrance concentrations have not been reported in NIST SRMs. The objective of this study was to provide reference values for several commonly detected synthetic musk fragrances in several NIST natural matrix SRMs. In this study five polycyclic musk fragrances [HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-γ-2-benzopyran), AHTN (7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene), ADBI (4-acetyl-1,1-dimethyl-6-tert-butylindane), AHMI (6-acetyl-1,1,2,3,3,5-hexamethylindane), and ATII (5-acetyl-1,1,2,6-tetramethyl-3-isopropylindane] and two nitro musk fragrances [musk xylene (1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene) and musk ketone (4-tert-butyl-3,5-dinitro-2,6-dimethylacetophenone)] were measured in selected environmental SRMs. Gas chromatography–electron impact mass spectrometry (GC/EI-MS) was used for all analyses. HHCB was the most frequently detected synthetic musk fragrance and was detected in SRM 2585 Organic Contaminants in House Dust, SRM 2781 Domestic Sludge, SRM 1974b Organics in Mussel Tissue (Mytilus edulis), and SRM 1947 Lake Michigan Fish Tissue. It was not detected in SRM 1946 Lake Superior Fish Tissue or SRM 1945 Organics in Whale Blubber. Concentrations of HHCB in these SRMs ranged from 1.12 ng/g in SRM 1947 to 92,901 ng/g in SRM 2781. All of the polycyclic musk fragrances were detected in SRM 2781 and all of the target compounds were detected in SRM 2585. Electronic supplementary material Supplementary material is available for this article at and is accessible to authorized users.     

层状固体模板组装有机/无机纳米结构材料

主要介绍了几种有机／无机层状固体模板组装纳米功能材料的研究进展，对模板的类型、制备、纳米结构材料的产生及其应用前景进行了综述。     

羧甲基木薯淀粉的取代方式研究

采用高效液相色谱(HPLC)和核磁共振波谱(^1HNMR)分析了混水/有机介质中合成羧甲基木薯淀粉的取代方式。发现HPLC是一种测定不同条件下合成的羧甲基木薯淀粉取代度(DS)的可靠方法。在测量的范围内,未取代、一取代、二取代和三取代无水葡萄糖单元的摩尔分数分布和Spurlin模型非常吻合。用高分辨率500MHz^1HNMR分析了木薯淀粉羧甲基过程的取代度和反应顺序。依据淀粉和羧甲基淀粉(CMS)的结构确定了各个峰位置。比较所得数据发现：依据HPLC计算的DSHPLC小于从500MHz^1HNMR计算所得的DSNMR。无水葡萄糖单元中C2、C3和C6的羧甲基化反应顺序为C6＞C2＞C3。     

层状纳米光催化复合材料H0.8Fe0.8Ti1.2O4/TiO2的合成及性质

用固相合成法制备出K0.8Fe0.8Ti1.2O4,并用离子交换反应制备出H0.8Fe0.8Ti1.2O4;通过C3H7NH2层间膨胀,TiO2粒子的插入和紫外光分解等反应,合成出一种新的层状光催化纳米复合材料-H0.8Fe0.8Ti1.2O4/TiO2.X射线衍射和漫反射等表征结果表明 该样品的层间高度为0.47nm,禁带能隙为2.18和2.88eV.用(>400 nm的光照射30 min,0.4 g样品可使甲基橙溶液(20 mg/L)的降解率达到22.1%.而同样条件下标准TiO2(P-25)仅为6.2%,表明所研制的层状纳米复合材料具有较高的光催化活性.