Cardo poly (ether sulfone) toughened E51/DETDA epoxy resin and its carbon fiber composites

A toughener that can effectively improve the interlaminar toughness in carbon fiber composites is crucial for various applications.We investigated,the toughening effects of phenolphthalein-based cardo poly(ether sulfone)(PES-C)on E51/DETDA epoxy and its carbon fiber composites(CFCs).Scanning electron microscopy showed that the phase structures of PES-C/epoxy blends change from island(of dispersed phase)structures to bi-continuous structures(of the matrix)as the PES-C content increased,which is associated with reaction-induced phase separation.After adding 15 phr PES-C,the glass transition temperature(T_(g))of the blends increased by 51.5℃,and the flexural strength,impact strength and fracture toughness of the blends were improved by 41.1%,186.2%and 42.7%,respectively.These improvements could be attributed to the phase separation structure of the PES-C/epoxy sys-tem.A PES-C film was used to improve the mode-II fracture toughness(G_(IIC))of CFCs.The G_(IIC) value of the 7μm PES-C film toughened laminate was improved by 80.3%compared to that of the control laminate.The increase in G_(IIC) was attributed to cohesive failure and plastic deformation in the interleaving region.

Ballistic Penetration Damage of Hybrid Thermoplastic Composites Reinforced with Kevlar and UHMWPE Fabrics

Polymer matrix types of fiber hybrid composites are key factors to improve ballistic impact damage tolerances.Here we report ballistic penetration damages of Kevlar/ultra-high molecular weight polyethylene(UHMWPE)hybrid composites with thermoplastic polyurethane(PU)matrix.The hybrid composites were penetrated by fragment-simulating projectiles(FSPs)using an air gun impact system.The effects of stacking sequences on the ballistic performance of hybrid composites were analyzed.Two types of specific energy absorption(the energy absorption per unit area density and the energy absorption per unit thickness)were investigated.It was found that the main damage modes of PU hybrid composites were fiber breakage,matrix damage,fiber pullout and interlayer delamination.The instantaneous deformation could not be used as a reference index for evaluating the ballistic performance of the target plate.The energy absorption process of the PU hybrid composites showed a nonlinear pattern.The hybrid structure affected the specific energy absorption of the materials.

Effects of chitosan coating on biocompatibility of Mg-6%Zn-10%Ca_3(PO_4)_2 implant

A Mg?6%Zn?10%Ca3(PO4)2 composite with a chitosan coating was prepared to study its in vivo biodegradation properties. The chitosan dissolved in a 0.2% acetic acid solution was applied on the surface of Mg?6%Zn?10%Ca3(PO4)2 composite specimens and solidified at 60 °C for 30 min to form the coating. The cytotoxicity evaluation of chitosan coated specimens is at level 0, which indicates that such coating is safe for cellular applications. The in vivotests of chitosan coated composite show that the concentration of metal ions from the composite measured in the venous blood of Zelanian rabbits is less than that from the uncoated composite specimens. The chitosan coating impedes the in vivo degradation of the composite after surgery. The in vivo testing also indicates that the chitosan coated composite is harmless to important visceral organs, including the heart, kidneys and liver of the rabbits. The new bone formation surrounding the chitosan coated composite implant shows that the composite improves the concrescence of the bone tissues. And the chitosan coating is an effective corrosion resistant layer that reduces the hydrogen release of the implant composite, thereby decreasing the subcutaneous gas bubbles formed.

千红万紫安排着，只待新雷第一声——高中“诗意作文”教学研究

对于“诗意作文”，漯河市高级中学是这样理解的：“诗意”不仅是作者的个性展现，能引读者入“有我之境”，还应妙语生辉，引读者察“境界全出”。一篇好的作文，不仅引人思考，而且以情动人。“诗意作文”既是对生活的再现、对岁月的留痕、对人性的聚焦、对心灵的解剖，又是对文字的舞动、对视觉的美化、对韵味的张扬。

Performance of rice-hull-PE composite exposed to natural weathering

Rice-hull powder is widely used in manufacturing reinforced plastic composites.However,its weathering ability is rarely considered.We studied the performance of two types of rice-hull-polyethylene（RH-PE） composites after they were exposed outdoor to natural weathering for two years.The samples did not change in bending strength and elasticity modulus.At the end of the testing period,colour lightness had increased by more than 23% and total colour had changed by more than 9 units.This means the colour evidently differentiate from the original colour that the customers choose.The analyses of Fourier-transform infrared（FTIR） and X-ray photoelectron spectroscopy（XPS） showed that oxidation had occurred on sample surfaces.Red lumber presented an obvious C=O peak after weathering,while yellow lumber did not present an obvious peak as evidence of oxidation.Both types of lumbers showed a reduction of lignocellulosic groups and amorphous regions of PE.

Recent advances in immobilized enzymes on nanocarriers

Recent progress in nanotechnology has provided high-performance nanomaterials for enzyme immobilization.Nanobiocatalysts combining enzymes and nanocarriers are drawing increasing attention because of their high catalytic performance,enhanced stabilities,improved enzyme-substrate affinities,and reusabilities.Many studies have been performed to investigate the efficient use of cellulose nanocrystals,polydopamine-based nanomaterials,and synthetic polymer nanogels for enzyme immobilization.Various nanobiocatalysts are highlighted in this review,with the emphasis on the design,preparation,properties,and potential applications of nanoscale enzyme carriers and nanobiocatalysts.

New method for measuring high field electrostrictive response of barium titanate/polyurethane elastomer

A new method for measuring the characteristic of electrostriction by a digital speckle correlation method （DSCM） is presented. The in-plane displacement is obtained by using the DSCM, and the out-plane displacement is obtained by the geometrical relation of the triangle theory. In this application, high field electrostrictive strains of barium titanate/polyurethane elastomer composite materials are measured. The electrostrictive strain is evaluated when the application of an electric field is repeated, and then the electrostrictive coefficient of the sample is obtained. To improve the measuring accuracy, the bilinear interpolation of gray value is used to obtain the sub-pixel gray value. The results are compared with those obtained from the surface fitting algorithm. The experimental results demonstrate that the electrostrictive response of polyurethane increases with the introduction of barium titanate into polyurethane. And by using the DSCM, the measurement of the characteristic of electrostriction can be done quickly and accurately. The DSCM provides an effective tool for the evaluation of electrostrictive response.

The Effect of Silane Grafted Polypropylente on the Property of Different Filler/Polypropylene Composites

Aim To determine the effect of silane grafted polypropylene on the property of different filler/polypropylene composites. Methods Polypropylene (PP) composites filled with talc(Ta), baryta sulfate and calcium carbonate coupled with silane grafted polypropylene (PP-g-Si) were made, their mechanical properties and thermal properties were investigated, respectively. Results As compared with the non-coupled composites, the mechanical properties of PP/Ta/PP-g-Si composites were improved to some extent, though the values of tensile modulus and the strain at peak were decreased. But for PP/BaSO4 and PP/CaCO3 composites, the values of their mechanical properties varied slightly or even decreased with increasing PP-g-Si content within the experimental component. Meanwhile, PP-g-Si also affected the melting and crystallization behavior of PP in the composites. Conclusion PP-g-Si offers compatibilization in PP/Ta composites, but offers no-compatibilization in PP/BaSO4 and PP/CaCO3 composites within the extent of the present range of PP-g-Si, which shows that PP-g-Si can be used as the macromolecular coupling agent of PP and Ta composite.

INTERFACE DAMAGE ANALYSIS OF FIBER REINFORCED COMPOSITES WITH DUCTILE MATRIX

A cohesive zone model is employed to simulate the fiber/matrix interface damage of composites with ductile matrix. The study is carried out to investigate the dependence of the interface damage and the composite tensile strength on the micro parameters of the composite. These parameters contain fiber packing pattern, fiber volume fraction, and the modulus ratio of the fiber to the matrix. The investigation reveals that though the high fiber vo lume fraction, the high fiber′s modulus and the square fiber packing can supply strong reinforcement to the composite, the interface damage is susceptible in these cases. The tensile strength of the composite is dominated by the interface strength when the interface debonding occurs.

Preparation and Flame Retardancy of Polyurethane/POSS Nanocomposites

Polyurethane/polyhedral oligomeric sisesquioxane （PU/POSS） nanocomposites were syn- thesized via polymerization utilizing the compatibility between POSS nanopartieles and 4J-diphenyl methylene diisocyanate. Scanning electron microscope images and Fourier transform infrared spectra revealed that POSS nanoparticles were dispersed in PU matrix. Thermal gravimetric analysis was employed to investigate the thermal decomposition be- havior of PU/POSS nanocomposites at elevated temperatures. Then fire performance was evaluated by limiting oxygen index, underwriters laboratories 94 testing and char residue morphology. These results showed that the addition of POSS promoted the formation of char residues which were covered on the surface of polymer composites, leading to the ira-provement of thermal stability and flame retardancy.

Enhancement of Rice Germplasm by Pyramiding the Cultivars with Multi-resistance to Orseolia oryzae (Wood-Mason)

[ Objective] This study was to breed rice cultivars with multi-resistance to Orseolia oryzae （Wood-Mason）. [ Method] The Guangxi local cultivar GX-M001 （Jiangchao） with high resistance to Orseolia oryzae （Wood-Mason） was used to hybrid with the known resistance cultivars ＂Kangwenqingzhan＂ （harboring GM5 gene）, OB677（ harboring GM3 gene） from Sri Lanka, HT1350 and high yield end quality cultivar ＂ Guiruanzhan＂. [ Result] Through pyramiding the multi-resistant genes via routine hybridization, the general resistances of the hybrids were remarkably enhanced. The grades of resistance were also improved, many of the combinations were endowed with a resistance at immune level （grade 0） ; and interestingly, the respective hybridization of GX-M001 （high resistance） with OB677（ medium resistance） and HT1350（suscepti- ble） also generate two lines at immune level, which is probably the effects of additive effects of genes.[ Conclusion] By routine hybridization, multiple genes were successfully pyramided, thus generating novel rice lines with multiple resistances. For the rice breeding scientists at the grass-roots level, the resistance-resistance pyramiding is an effective approach to breed high resistance cultivars.

Effect of chemical modification on the properties of wood/polypropylene composites

Aluminate-based coupling agent was added as a compatibilizer to make the chemical modification of wood powder. The mechanical properties and morphology of wood powder/polypropylene composites were studied. The results showed that the compatibilizer can increase the impact strength of the wood/polypropylene composites, but it has a slightly negative effect on the tensile and flexural strength. For dynamic mechanical properties and Differential Scanning Calorimetry, Aluminate-based coupling agent can slightly increase the storage modulus and loss modulus, and decrease the melt point and the Calorie of Melt. Scanning electron microscopy showed that Aluminate-based coupling agent had a stronger affinity between the wood and polypropylene surfaces. These results suggested that Aluminate-based coupling agent may play a useful role in improving wood powder/polypropylene composites properties.

Clustering Analysis on Large Grained Brassica napus Materials Based on the Optimized ACGM Markers

[Objective] This study aimed to develop ACGM markers for the clustering analysis of large grained Brassica napus materials. [Method] A total of 44 pairs of ACGM primers were designed according to 18 genes related to Arabidopsis grain development and their homologous rape EST sequences. After electrophoresis, 18 pairs of ACGM primers were selected for the clustering analysis of 16 larger grained samples and four fine grained samples of rapeseed. [Result] PCR result showed that 2-6 specific bands were respectively amplified by each pair of primes, and all the bands were polymorphic and repeatable, suggesting that the optimized ACGM markers were useful for clustering analysis of B. napus species. Clustering analysis revealed that the 20 rapeseed samples were divided into three clusters A, B, and C at similarity coefficient 0.6. Then, the clusters A and B were further divided into five sub clusters A1, A2, A3, B1 and B2 at similarity coefficient 0.67. [Conclusion] This study will provide theoretical and practical values for rape breeding.

Polyoxovanadate(NH_4)_7[MnV_(13)O_(38)] as cathode material for lithium ion battery and improved electrochemical performance

The polyoxovanadate（NH4）7[MnV13O38]（AMV） was synthesized and characterized by X-ray diffraction pattern, Fourier transform infrared spectra, and field emission scanning electron microscope equipped with energy dispersive X-ray spectroscopy. In order to improve the electrochemical performance of AMV, the particle size of as-prepared AMV is decreased to nanoscale by re-precipitation in the water-ethanol solution. The results of the electrochemical impedance spectra and the 4-pin probe measurements show that the electrical conductivity of AMV is improved by decreasing the particle size. The nanoparticle AMV shows higher initial discharge capacity and energy density than the as-prepared AMV when cycled at 0.5C. On the other hand, the nanoparticle AMV exhibits higher rate capability than the as-prepared AMV.

IN-SITU POLYMERIZED SYNTHESIS AND PROPERTIES OF NANO-ZnO/PEG/PET COMPOSITE

Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized via in-situ polymerization. The dispersion of nZnOp in copolymer matrixes and the effects of PEG and nZnOp particles on the crystallization behavior of the composites are studied by TEM, differential scanning calorimetry（DSC）, XRD and Fourier thansform infrared spectroscopy （FTIR ）. The results reveal that nZnOp particles are dispersed in the matrixes with nano-scale, and the addition of PEG induces more homogeneous dispersion of nZnOp. Simultaneously, these nanoparticles become nucleating centers during the crystallization of the matrixes. PEG segments can improve the flexibility of the PET molecular chain, resulting in the drop of the cold crystallization temperature and the rise of the crystallization rate of the composites. Furthermore, PEG （4 000） with the mass fraction of 10% can promote the crystallization rate of the composites. The mechanical properties show that the nano-particles strengthen and toughen the PET matrix, whereas PEG weakens these improve- ments.

Synthesis and Characterization of a Novel Biomaterial: Maleic Anhydride-modified Poly(dl-lactic acid)

A novel modified poly(dl-lactic acid) (PDLLA) was obtained by covalently grafting of maleic anhydride onto the backbone of PDLLA, attempting to improve PDLLA’s hydrophilicity and cell affinity and to provide reactive groups for further chemical modification. FTIR, 13C NMR and DSC were used to characterize the maleic anhydride-modified PDLLA.

Preparation and properties of geopolymer-lightweight aggregate refractory concrete

Geopolymer-lightweight aggregate refractory concrete (GLARC) was prepared with geopolymer and lightweight aggregate. The mechanical property and heat-resistance (950 ℃) of GLARC were investigated. The effects of size of aggregate and mass ratio of geopolymer to aggregate on mechanical and thermal properties were also studied. The results show that the highest compressive strength of the heated refractory concrete is 43.3 MPa,and the strength loss is only 42%. The mechanical property and heat-resistance are influenced by the thickness of geopolymer covered with aggregate,which can be expressed as the quantity of geopolymer on per surface area of aggregate. In order to show the relationship between the thickness of geopolymer covered with aggregate and the thermal property of concrete,equal thickness model is presented,which provides a reference for the mix design of GLARC. For the haydite sand with size of 1.18-4.75 mm,the best amount of geopolymer per surface area of aggregate should be in the range of 0.300-0.500 mg/mm2.

Superabsorbent Capability and High Retention Ability of China Clay(Kaolinite)/Polyacrylic Acid Composites for Aqueous Solution

Majority of superabsorbent polymers (SAPs) yet reported either have low gel strength or high production cost. Therefore, we synthesized a novel polyacrylic acid-grafted China clay (Kaolinite) super-absorbent polymer composite (SAPC) with high thermal stability, low cost of production and superior sorption and retention capability for water and salt solution. The resulting SAPCs were extensively characterized and analysed by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Results suggested that the composites were thermally stable. Water absorbency increased with increase of clay content up to 45%, while further increase in clay content decreased the water absorbency. Percentage of acrylic acid (AA) and clay by weight shows the optimum absorbency in 35% and 40% respectively. Crosslinker and initiator contents were optimized to be 0.5% and 0.3% by weight respectively. The resulting polymer composite showed high water absorbency of about 785 g/g and 103 g/g of 1% NaCl solution with above 90% retention ability at 50 oC.

Strength and thermal behavior of low weight foam geopolymer using circulating fluidized bed combustion fly ash

A comparative study of the influence of elevated temperature on foam geopolymer using circulating fluidized bed combustion fly ash（CFA） was reported. Foam geopoymers were prepared with different amounts of foam agent and different Si O2/Al2O3 molar ratios of 3.1, 3.4, and 3.8. The mechanical, thermo-physical properties and microstructure of the foam geopolymers before and after exposure to elevated temperature of 800, 1000, and 1200 ℃ were investigated. The specimen with Si O2/Al2O3 molar ratio of 3.8 exhibits the highest compressive strength, better microstructure and dimension stability before and after firing. Carnegeite, nepheline, and zeolite crystalline phases appearing after exposure may contribute to the good post-exposure strength. Low weight foam geopolymer using CFA can increase strength and maintain higher stability as high as 1000 ℃.

Preparation and characterization of eco-friendly poly(p-phenylenediamine) and its composite with chitosan for removal of copper ions from aqueous solutions

Poly(p-phenylenediamine)/chitosan (PPPDA/Chi) composite was prepared by in situ chemical oxidative polymerization of p-phenylenediamine (PPPDA) into chitosan (Chi) using ammonium persulphate (APS) as an oxidant. PPPDA and PPPDA/Chi composite were characterized by FT-IR spectra and SEM before and after copper loading. In batch adsorption method, the maximum removal of copper was experienced when 1 g/L of PPPDA and PPPDA/Chi composite dosages were used at pH 5.0 for PPPDA and 6.0 for PPPDA/Chi composite for 360 min for both sorbents. PPPDA showed adsorption capacity qemax of 650 mg/g whereas its composite achieved qemax of 573 mg/g. The experimental data correlate well with the Freundlich isotherm equation and the pseudo-second order kinetic model. The Cu(II), loaded PPPDA and its composite can be efficiently reused for as many as four cycles. The Cu(II)-loaded sorbents showed high antibacterial efficiency against Gram-positive and Gram-negative bacteria than their unloaded forms.