Evaluation of Dispersion Based Calculations Compared to the Experimental Compressive Strength Results of CNT/6063AI Composites

Nowadays, it is vital to predict strength results of composites in advance of manufacturing process to reduce testing costs; especially in carbon nanotube （CNT） reinforced metal matrix composites. Therefore, compressive mechanical properties of fabricated CNT reinforced aluminum （AI） matrix composites are investigated and compared with the calculation results of dispersion based prediction models. First of all, CNT/6063 AI composites are fabricated by vacuum assisted infiltration of molten 6063 AI alloy into the CNT preform. Then, compressive mechanical properties of these composites are determined. Eventually, model calculations and experimental results are visualized by plotting comparison graphs. As a result, correlation between prediction models and experimental results are established and potential results of difference between these results are discussed.     

Annealing Effect on the Ionic Conductivity of La0.6-.xLi3xTiO3 Made by Double Mechanical Alloying Method

Perovskite La2/3.xLi3xTiO3 with x = 0.11 （called LLTO11） powders were prepared by double mechanical alloying method from TiO2 （99.99%）, Li2CO3, （99.99%） and La203 （99.9%） powders, in ideal cation stoichiometry for La2/3_xLi3xTiO3. The obtained single phase of LLTO11 powder was isostatically pressed under a pressure of 450 MPa and annealed at a temperature ranging from 1,100 ℃ to 1,250 ℃. Optimal morphology and grain structure for the ionic conductivity of the samples were achieved at annealing temperature of 1,200 ℃. For this ceramic, the lithium ionic grains and grain-boundaries conductivities at room temperature possess a value of 1.5 × 10-3 S/cm and 4.8 × 10-5 S/cm, respectively. The improvement in the grain-boundaries conductivity was explained due to the decrease of the number of grains, included grain boundaries and the diminution of the pores in LLTO samples annealed at 1,200 ℃. The obtained results suggest useful applications of Lai2/3）.xLi3xTiO3 （x = 0.11） ceramics for the production of the solid state electrolytes, for high-temperature Li-ionic batteries, in particular.     

Poly（Vinyl Chloride） Nanocomposites Prepared in the Suspension Polymerization Process. Part I. PVC Filled with Hybrid Nanofiller

PVC syntheses were done by suspension polymerization in the presence of hybrid silicone/acrylic core-shell type nanofiller. The moldings made from PVC nanocomposites are fully homogeneous and of good transparency. SEM images show very good, uniform dispersion of nanofiller in PVC matrix. The blends made from nanocomposites show higher tensile strength （-10%） and tensile modulus （20% higher for nanofiller amount equal to 0.2 wt.%/VCM） than PVC homopolymer. The impact strength of all samples made from PVC nanocomposites are higher than of PVC. Blends of nanocomposites containing 0.5 or 1.0 wt.%/VCM of nanofiller show the best impact strength： 28 and 32% better than PVC, respectively. Nanocomposites containing 0.5 wt.%/VCM of core-shell nanofiller show the highest stiffness. The nanofiller used practically does not influence thermal properties of the polymer. The use of PVC nanocomposites in typical PVC applications gives possibility to obtain the novel PVC products with the properties better than the present ones as well as the possibility to reduce processing costs via reduction of processing aids amounts, especially impact modifiers, what additionally will lead to tensile properties improvement.     

Preparation and characterization of novel biodegradable composites based on acylated cellulose fibers and poly(ethylene sebacate)

The preparation and characterization of biodegradable composite materials with improved properties based on poly(ethylene sebacate) (PES) and acylated cellulose fibers is reported. These biocomposites showed improved mechanical properties, as evidenced by the increase in both elastic and Young moduli and in the tensile strength, and also showed low water sensitivity and a high biodegradability rate. These novel biocomposites were prepared essentially from renewable resources and therefore constitute an important contribution to the development of the area of sustainable composite materials.     

纤维素溶剂体系的研究进展

纤维素是自然界含量最丰富的可再生资源,开发一种具有应用前景、环境友好、生物可降解的新型绿色溶剂成为近年来的一项主要任务。综述了传统纤维素的溶解方法,包括铜氨溶液体系和二硫化碳/氢氧化钠(CS2/NaOH)体系,介绍了新型纤维素溶剂NMMO、离子液体等,探讨了各种体系的溶解机理及其优缺点,并在此基础上提出了溶剂法生产纤维素纤维的进展和趋势。     

Studies of the effect of molding pressure and incorporation of sugarcane bagasse fibers on the structure and properties of poly (hydroxy butyrate)

Poly (hydroxy butyrate) (PHB) is a biodegradable polymer that can be obtained from both renewable and synthetic resources. There have been many attempts to improve its structure and properties by different methods. This paper, while mentioning briefly PHB and sugarcane bagasse fibers, focuses on the effect of compressive/molding pressure on its structure and thermal properties with incorporation of sugarcane bagasse fibers, with and without steam explosion treatment. Thermal behavior (thermogravimetry and dynamic mechanical analysis), X-ray diffraction, Fourier transform infrared spectroscopy, optical microscopy methods were used to understand the changes in PHB resulting from the pressure and incorporation of fibers while scanning electron microscopy is used to understand the morphology of both the fiber and PHB.     

Chitosan based edible films and coatings: A review

Chitosan is a biodegradable biocompatible polymer derived from natural renewable resources with numerous applications in various fields, and one of which is the area of edible films and coatings. Chitosan has antibacterial and antifungal properties which qualify it for food protection, however, its weak mechanical properties, gas and water vapor permeability limit its uses. This review discusses the application of chitosan and its blends with other natural polymers such as starch and other ingredients for example essential oils, and clay in the field of edible films for food protection. The mechanical behavior and the gas and water vapor permeability of the films are also discussed. References dealing with the antimicrobial behavior of these films and their impact on food protection are explored.     

植物油基泡沫塑料的研究进展

植物油基泡沫塑料环境友好,综述了植物油制备泡沫塑料的研究进展,主要介绍了植物油的基本组成,并根据泡沫基体材料组成对植物油基泡沫材料进行了分类,分析了植物油改性制备泡沫塑料的主要方法、种类、反应机理及其对材料性能的影响,展望了植物油基泡沫塑料的发展和应用方向。     

Polylactic Acid Technology

Polylactic acid is proving to be a viable alternative to petrochemical‐based plastics for many applications. It is produced from renewable resources and is biodegradable, decomposing to give H₂O, CO₂, and humus, the black material in soil. In addition, it has unique physical properties that make it useful in diverse applications including paper coating, fibers, films, and packaging (see Figure).     

Natural fibre-reinforced composites for bioengineering and environmental engineering applications

Recently, the mankind has realized that unless environment is protected, he himself will be threatened by the over consumption of natural resource as well as substantial reduction of fresh air produced in the world. Conservation of forests and optimal utilization of agricultural and other renewable resources like solar and wind energies, and recently, tidal energy have become important topics worldwide. In such concern, the use of renewable resources such as plant and animal based fibre-reinforce polymeric composites, has been becoming an important design criterion for designing and manufacturing components for all industrial products. Research on biodegradable polymeric composites, can contribute for green and safe environment to some extent. In the biomedical and bioengineered field, the use of natural fibre mixed with biodegradable and bioresorbable polymers can produce joints and bone fixtures to alleviate pain for patients. In this paper, a comprehensive review on different kinds of natural fibre composites will be given. Their potential in future development of different kinds of engineering and domestic products will also be discussed in detail.     

Origin of high mechanical quality factor in CuO-doped （K,Na）NbO3-based ceramics

The origin of a high mechanical quality in CuO-doped （K, Na）NbO3-based ceramics is addressed by considering the correlations between the lattice positions of Cu ions and the hardening effect in K0.48Na0.52＋xNbO3-0.01CuO ceramics. The Cu ions simultaneously occupy K/Na and Nb sites of these ceramics with x = 0 and 0.02, only occupy the K/Na site of the ceramics with x= -0.02, and mostly form a secondary phase of the ceramics with x = -0.05. The Cu ions lead to the hardening of ceramics with an increase of Ec and Qm by only occupying the K/Na site, together with the formation of double hysteresis loops in un-poled compositions. A defect model is proposed to illuminate the origin of a high Qm value, that is, the domain stabilization is dominated by the content of relatively mobile O2- ions in the ceramics, which has a weak bonding with CUK/Na defects.     

Development and characterization of a laminate composite material from polylactic acid (PLA) and woven bamboo fabric

This article presents the development and mechanical characterization of a composite material fabricated from both renewable resources and biodegradable materials: bamboo woven fabric as reinforcement and polylactic acid (PLA) as resin matrix. The laminate composites were produced using a film stacking method. The physical, thermal, and, mechanical properties of bamboo fabric, PLA matrix, and laminate composites were investigated. It is shown that the breaking force of the plain woven bamboo fabric in the weft direction was greater than in the warp direction. Further, the tensile, flexure, and, impact properties of PLA increased when weft direction bamboo fabric reinforcement is used. In addition, scanning electron microscopy examination of laminate composite showed good bonding between bamboo fiber and PLA resin. In summary, laminated composites based on polylactic acid and bamboo fabric display excellent energy absorption capability, which can be exploited for the development of engineering structural applications.     

Binderless all-cellulose fibreboard from microfibrillated lignocellulosic natural fibres

Fully biobased all-cellulose fibreboards are produced without the use of additional bonding agents such as polymer resins or binders as in the case of e.g. medium density fibreboard (MDF) or natural fibre reinforced plastic (NFRP). These materials make use of the self-binding capability of cellulose, exploiting the enhanced hydrogen bonded network present in micro- and nanofibrillated cellulose, resulting in good mechanical performance. After the optimisation of refinement, drying and hot-pressing conditions, binder-free panels from microfibrillated flax fibres with excellent mechanical properties of around 17 GPa and 120 MPa for flexural modulus and strength, and relatively low water sorption are achieved, making these materials competitive with conventional cellulose based composite materials. The work shows the potential of creating all-cellulose engineering materials using only the intrinsic bonding capacity of microfibrillated lignocellulose, potentially leading to environmentally friendly panel board materials, which are entirely based on renewable resources, recyclable and biodegradable.     

Mechanical characteristics of glass fibre reinforced polymer made of furfuryl alcohol bio-resin

Conventional fiber reinforced polymers (FRPs) require polymers such as epoxies that are not biodegradable, which have a significant impact on the environment. This study aims at replacing conventional polymers with bio-polymers which are more sustainable. The study investigates the tensile mechanical properties of glass-FRP (GFRP) laminates fabricated by wet layup using two types of organic furfuryl alcohol bio-resins extracted renewable resources, such as corncobs. Results are compared to control specimens fabricated using conventional epoxy resin. The study investigates the effects of catalyst type and dosage as well as the curing time on the tensile strength and modulus of the GFRP. The study also investigates the optimal overlap splice of the laminates. It was shown that by careful selection of viscosity of bio-resin, and type and dosage of catalyst similar mechanical properties to epoxy-GFRP can be achieved. The optimal catalyst proportion was 3 % by weight. Full strength occurred after 13 days curing but 84 % occurred in 2 days. The optimal lap splice length was 200 mm, however, the maximum strength was only 68 % of the full ultimate tensile strength as bond failure always governs at the splice.     

离子液体对纤维素溶解性能的研究进展

纤维素是自然界含量最丰富的可再生资源,开发一种具有应用前景、环境友好、生物可降解的新型绿色溶剂成为近年来的一项主要任务。离子液体作为纤维素的非衍生化溶剂,在纤维素研究中呈现出了良好的发展态势。综述了国内外离子液体对纤维素溶解、再生的近期研究成果,分析了纤维素在溶解过程中存在的问题,并探讨了纤维素的溶解机理,提出了离子液体溶解纤维素的发展方向。     

纤维素长链脂肪酸酯的合成进展

纤维素是地球上储量最大的天然高分子材料,随化石资源的稀缺性日益凸显,纤维素的开发与应用愈来愈受到重视。作为纤维素重要衍生物之一,纤维素长链脂肪酸酯具有良好的生物降解性、有机溶剂可溶性、可熔融加工性等优点,可应用于诸多领域,其研究开发具有重要意义。综述了近年来纤维素长链脂肪酸酯的合成方法,涵盖了在DMF、甲苯、吡啶等惰性溶剂中的非均相衍生化和诸如在DMAc/LiCl体系、DMSO/TBAF体系、离子液体等中的均相酰化。     

Faserverbundwerkstoffe aus nachwachsenden Rohstoffen für den ökologischen Leichtbau

Fiber composites of raw renewable materials for the ecological lightweight design Due to their low density natural fibers have the potential to be outstanding reinforcements in lightweight structures. Since most natural fibers are hollow they also bear great potentials in offering an increased bending resistance and buckling strength. By imbedding natural fibers in organic polymers instead of in conventional petroleumbased polymers a unique completely renewable and if wanted biodegradable composite can be created. Structural components made up of this new composite material cannot only be recycled or burned (in this case even CO₂-neutral), but also be reintegrated in the cycle of natural decomposition. Presently e.g. car door linings or instrument panels have no supporting function in the car structure. In the future generation of cars weight reduction can be achieved giving these elements reinforcing functions by integrating hollow natural fibers aligned in the main loading directions. Furthermore critical regions in therms of stiffness and strength where loads are applied, like e.g. fastenings for side airbags, can be realised in the the same material without addition of metals. This can also be achieved for any other application. In this paper the potential of hallow natural fibers for reinforcements of lightweight structures, the renewable and (if wanted) biodegradable composites and their application in technical constructions will be discussed.     

Removal of Arsenic from Waste Water by Using ZnO Nano-Materials

Zinc oxide has a unique position among semiconducting oxides due to its piezoelectric and transparent conducting properties. The catalyst-free synthesis of pure ZnO nanostructured material with 6-fold structural symmetry was synthesized by the chemical precipitation method. In this article, various nanostructures of ZnO which are grown by the chemical precipitation technique has been reported. Zinc oxide nanoparticles were synthesized by heating freshly prepared zinc hydroxide [Zn（OH）2] at 150℃ for two hours. The prepared compound was characterized by the X-Ray diffraction technique. Zinc oxide nanoparticles possess high removal capacity of As （III）, which can easily be separated and recycled during water treatment processes.     

Study of the Adsorption Space of Modified Clinoptilolites

Carbon dioxide （CO2） adsorption is an important adsorbent characterization method and a significant industrial process. In separation and recovery technology, the adsorption of the CO2 is important to reduce the concentration of this gas considered as one of the greenhouse gases. Natural zeolites, particularly clinoptilolite, are widely applied as adsorbents. In this regard, in the present research, the structure, composition and morphology of modified with hexafluorosilicate （HFSi） and orthophosphoric acid （H3PO4） clinoptilolites were investigated by characterizations and measurements made with, X-ray diffraction （XRD）, thermogravimetric analysis （TGA）, scanning electron microscopy-energy dispersive X-ray analysis （SEM-EDAX） and gravimetric adsorption. Additionally, the surface Chemistry of the modified clinoptilolites was analyzed by applying diffuse reflectance fourier transform infrared spectrometry （DRIFTS）. Further, the interaction of CO2 within the adsorption space of these modified clinoptilolites and a synthetic ZSM-5 zeolite was studied with the help of adsorption measurements. After all, an appropriate theoretical methodology for the analysis of the XRD and adsorption data was applied. The calculated cell parameters of the tested are similar to those reported for a typical clinoptilolite of： a = 17.662 A, b = 17.911A, c = 7.407 ~ and fl = 116.40 The resolution of the TGA derivative profiles indicated the presence of two steps for water release, one of them represents the loss of majority of the water present in the micropores. This was evidenced as a broad peak centered at about 50℃ for the CSW-HFSi-0.1, but at 100 ℃ for the samples CSW-HFSi-0.4. The SEM micrographs corresponding to the modified clinoptilolites, was evidenced that the CSW zeolite shows secondary particles exhibiting diameters from 3 to 40 μm, formed by primary clinoptilolite crystallites showing a crystallite size, φ = 40 nm. The EDAX elemental analysis it can be demonstrated that the exchange process replaced about 85% of the charge compensating ions. The DRIFT spectra of the modified clinoptilolites, specifically, CSW-HFSi-0.1, show a narrow band at about： 3,740 cm-1 corresponding to terminal silanol groups （Si-OH） and a band 3,600-3,650 cm1 resulting from extra-framework AI-OH. With the precision of the measured micropore volumes related to the excellent fitting of the adsorption data by the D-R isotherm equation, it can be affirm that carbon adsorption took only place in the micropore region. The isosteric heat of adsorption calculated for the modified clinoptilolites was greater than those values reported of ZSM-5 zeolite, particle packing silica, dealuminated Y zeolite （DAY） Cd, Zn and Ni-nitroprussides and Cu-nitroprusside and a Ni-MOF. With the obtained result it can be concluded that the modified clinoptilolites with HFSi showed a quality as adsorbent comparable to commercial synthetic zeolites.     

Composites from Natural Fibers and Soy Oil Resins

The goal of this project is to develop new composites using fibers and resins from renewable resources. The ACRES (Affordable Composites from Renewable Sources) group at the University of Delaware has developed new chemistries to synthesize rigid polymers from plant oils. The resins produced contain at least 50% plant triglycerides and have mechanical properties comparable to commercially available synthetic resins such as vinyl esters, polyesters and epoxies. This project explores the development of all-natural composites by using natural fibers such as hemp and flax as reinforcements in the ACRES resins. Replacing synthetic fibers with natural fibers has both environmental and economic advantages. Unlike carbon and glass fibers, natural fibers are abundantly available from renewable resources. In terms of cost, natural fibers are cheaper than the synthetic alternatives. The natural fibers and plant-based resins have been shown to combine to produce a low cost composite with good mechanical properties. Tensile strength in the 30 MPa range has been obtained for a composite containing about 30 wt% Durafibre Grade 2 flax. The tensile modulus was found to be 4.7 GPa for a 40 wt% flax composite. Similar numbers where obtained for the hemp composites obtained from Hemcore Inc. Composites from renewable resources offer significant potential for new high volume, low cost applications.