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《Composite Interfaces》2013,20(8-9):687-699
High-pressure low-density polyethylene (HLDPE)/organic functionalized SiO2 nanocomposites were synthesized using melt-blending technique in a sigma internal mixer. The properties of the nanocomposites were studied using two different organic functional modifiers: diglycidyl ether of bisphenol-A (DGEBA) and triacetoxyvinylsilane. Reinforcing, thermal stability and toughening effects of organic functionalized nanosilica on the polymer matrix were found at loading of 2.5% nanosilica functionalized with 2.8% of DGEBA and silane coupling agent respectively. Organic functionalization on the nanosilica particle surface led to different microstructures when compared with that of the pure polymer. Organic functionalization on the nanosilica particle surface produced good interfacial adhesion and homogeneous dispersion in the polymer matrix, while the use of nanosilica resulted in aggregated silica particles in the polymer matrix. There was no significant improvement in thermal stability and mechanical properties when only nanosilica was added to the pure polymer. On the contrary, the addition of pretreated nanosilica with organic functional modifiers led to an increase of thermal stability from 313–363°C, elastic modulus and toughness from 0.12–0.18 GPa and 3.23–9.81 MJ/m3 respectively. 相似文献
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《Composite Interfaces》2013,20(7-9):647-668
This paper aims at introducing a new natural composite used as soil stabilizer with particular application in geotechnical engineering. The fibers introduced in the present study could be used as effective soil reinforcement. This research proves the feasibility of the use of modified jute/polypropylene in lime and cement composites and studies their effects on the tensile and compressive strength of the matrix. In general, the optimal mechanical performance of natural composites and durability depends on the optimization of the interfacial bond between natural fiber and matrix. Since the fibers and matrices are chemically different, strong adhesion at their interfaces is needed for an effective transfer of stress and bond distribution throughout an interface. In this paper a theoretical approach for the identification of elastic modulus in composite interfaces is proposed in detail with a reasonable error. The theoretical approach is based on the method using a sum of least squares criterion. The approach is applied through optimization techniques, using analytical sensitivities and correlating adhesion with Young's modulus. The validity and potentiality of the proposed technique is discussed and the results demonstrated the versatility, accuracy, and efficiency of the presented approach. The applied method also appears to be a simple way of predicting the modulus of elasticity in composite interfaces. This leads to a discussion of the most promising stabilization methods for soil reinforcement and the outlook for the future. 相似文献
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《Composite Interfaces》2013,20(7-9):605-616
The influence of chemical treatments on the interfacial adhesion of sisal fibres and biodegradable matrices were studied in the present work. For that purpose, four different polymers were used: polycaprolactone (PCL), cellulose acetate, MaterBi Z (a commercial starch/polycaprolactone blend) and MaterBi Y (a commercial starch/cellulose derivatives blend). Alkaline and acetylation treatments were performed on sisal fibres. Properties were determined by means of tensile tests, adhesion measurements and contact angle determination. The interfacial shear strength was correlated with the hydrophilic character of the material. 相似文献
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《Composite Interfaces》2013,20(8-9):617-629
A carboxylic gel-type resin, poly-4-vinylpyridine-methacrylic acid-N, N'-methylenebisacrylamide is designed and synthesized in order to be able to incorporate both FeIII and, potentially, also AuIII in its polymer framework. Along with the gradual substitution of H+ with Na+, of Na+ with Fe3+/3 and after a very controlled and gradual precipitation of FeIII as oxihydroxides induced by the hydrolysis of urea directly inside the nanoporous domains of the metalated resin particles, an organic-inorganic composite is obtained. The material is characterized with TGA, ESEM, XRMA and Mössbauer spectroscopy. 相似文献
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《Composite Interfaces》2013,20(7-9):581-604
To tailor the interaction across composite interfaces especially for the development of green composites, i.e. composites made completely from renewable materials, information about the fibre surfaces is required. We review the current state of the art of methods to determine the surface tension of natural fibres and discuss the advantages and disadvantages of techniques used. Although numerous techniques have been employed to characterise surface tension of natural fibres, it seems that commonly used wetting techniques are very much more affected by the non-ideal character of natural fibres. Inverse Gas Chromatography (IGC) is a much better suited technique to determine the surface energetic properties of natural fibres than wetting techniques. The surface tension of natural reinforcements, determined using IGC, was reported for nanosized bacterial cellulose as well as bamboo, cornhusk, flax, hemp and sisal, covering a wide range of cellulose content. The effect of methods to separate/extract fibres from the plants as well as of a few surface modification procedures on the fibre surface properties is also reviewed. The dispersive part of the natural fibre surface tension γ d S varies from 32 to 61 mJ/m2. The fibre surface tension increases with increasing cellulose content of natural fibres. We also found that a higher basicity (Donor Number, K B to Acceptor Number, K Aratio) was observed for fibres containing more cellulose. This may be reflective of higher crystalline cellulose content in the surfaces of the fibres, as only the ether linkage of the cellulose is labile for hydrogen bonding. 相似文献
6.
《Composite Interfaces》2013,20(2-3):335-349
In this research the adhesion and the resulting interfacial shear strength (IFFS) between the natural fibres flax, hemp and cotton and the polymer matrices polypropylene with coupling agent (MAPP) and polylactide acid (PLA) was surveyed with the single fibre fragmentation test (SFFT). The adhesion between MAPP and the fibres was good enough to produce fragments, whereas the adhesion between PLA and flax was too weak to transmit enough tension for fibre cracks which is clearly visible on SEM-photographs. Comparing the IFFS values of the fibres in MAPP with an equal fibre diameter shows that the IFFS value of flax is highest with 7.09 N/mm2 followed by hemp 6.13 N/mm2. The IFFS of cotton is a lot smaller (0.664 N/mm2). The critical fragmentation or fragmentation length of the bast fibres flax (3.16 mm) and hemp (3.20 mm) in MAPP is smaller than the critical fragmentation length of cotton (5.03 mm). The adhesion between the lignocellulosic fibres and MAPP is much better than between the lignin and pectin free cellulose fibre and MAPP. Possible reasons for this — the surface structure of the cotton fibre and its different chemical composition being made up of only cellulose, hemi-cellulose and wax with no pectin or lignin present — are discussed. 相似文献
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卤代苯和苯酚衍生物的位电荷密度能和logKow与-lgLC50的QSAR研究 总被引:7,自引:0,他引:7
以简易的量子化学方法计算了二十多种卤代苯和苯酚衍生物的FMO位电荷密度 能,并进行定量结构-活性相关(quantitive structrue biodegradability)研究 ,获得满意的结果。最后从生物酶促反应本质、污染物-生物酶的轨道控制反应角 度对QSAR提出新的解释。 相似文献