bluuebunny/crossref_metadata_2025 huggingface dataset:
Composites of Rice Husk/Wheat Straw with Pmdi Resin and Polypropylene
Authors: Frounchi Masoud , Dadbin Susan , Jahanbakhsh Javad , Janat-Alipour Mojtaba
Published: September 2018

The application of agricultural fibers for making particleboards has been studied in two types of composites: (i) type I particleboards were composites of wheat straw and rice husk fibers with polymeric methylene di-phenyl diisocyanate resin (pMDI) as a binder made by compression moulding; (ii) type II particleboards were composites of rice husk and polypropylene made by extrusion and injection moulding. In type I particleboards, the effects of varying the resin content and various combinations of wheat straw/rice husk fibers were investigated and characterised in terms of physical and mechanical properties of particle boards such as modulus of rupture, modulus of elasticity, compression strength, density, dimensional stability and water absorption. Results indicated that with increasing binder content, the physical and mechanical properties were improved until an optimum level of binder content was reached. Particleboards made of wheat straw blended with 6% pMDI showed a maximum MOE. Dimensional stability and water absorption of particle-boards made by combining wheat straw and rice husks were superior to those made only from wheat straw.

In type II particleboards, the non-polar polypropylene had poor affinity with rice husk, which resulted in weak interfacial adhesion and low mechanical properties. Tri-methoxy vinyl silane as coupling agent and maleic anhydride-grafted polypropylene (MAPP) as compatibiliser were used to obtain improved interfacial adhesion. The interface-treated composites were characterised by measuring tensile strength, tensile modulus, impact strength and optical microscopy. The combination of silane and MAPP proved effective in improving interfacial adhesion between polypropylene and rice husk. The improved interface allowed effective transfer of mechanical stress through boundary regions as verified by better mechanical properties. The latter was confirmed by the improved interface morphology of composites. The best impact strength result was obtained at a combination of 1.5 wt.% silane and 5 wt.% MAPP in all rice husk composites.
Characterisation and Properties of Abs Nanocomposite Prepared from Functionalised Montmorillonite Masterbatches
Authors: Xia Ying , Duan Xiaowei , Li Jianfeng , Han Jianzhu , Jian Xigao
Published: September 2018

A new approach for the preparation of exfoliated acrylonitrile-butadiene-styrene (ABS) nanocomposites is reported, involving two steps, i.e. the preparation of functionalised montmorillonite masterbatch (FMMT) and its melt blending with ABS. FMMT was prepared by adding acrylamide monomer (AA), organic-MMT (OMMT) and initiator dibenzoylperoxide (BPO) to ABS carrier which was first dissolved in 1,2-dichloroethane. IR, XRD and TEM analysis confirmed that AA was successfully grafted onto ABS and the masterbatch was a kind of intercalated nanocomposite. When FMMT was blended with ABS, the resulting ABS/FMMT composite had an exfoliated morphology judging from the results of XRD and TEM examination

DSC and TGA data demonstrated that the thermal properties of ABS/FMMT nanocomposite were better than those of pure ABS and ABS/OMMT nanocomposites prepared by directly melt blending of OMMT with ABS. The increase in interfacial interaction and compatibility between ABS matrix and FMMT resulted in a remarkable improvement in the mechanical properties. The tensile modulus and strength were superior to those of ABS/OMMT, and the decrease in impact strength caused by OMMT was moderated.
Thermal Exchanges and Thermomechanical Couplings in Amorphous Polymers
Authors: Germaneau A. , Dupré J.C.
Published: September 2018

During mechanical loading, the strain process can be accompanied by thermal effects generated by thermomechanical couplings. The aim of this work was the determination of energy (heat sources, mechanical energy, internal dissipated energy) during a mechanical test on polymer materials by observing strain and thermal data fields. Heat sources were calculated by establishing the heat equation using concepts of the classical thermodynamics of irreversible processes and applied to polymer materials. With a simple experimental set-up, we show that the thermal exchanges and the thermal losses in polymer samples are mainly induced by conduction and convective. The temperature at the surface was assumed to be equal to the average temperature in the thickness. We show that it is possible to obtain heat source values quantitatively without knowing their position and dimension along the thickness. It can also be difficult to calculate heat sources correctly because of lack of knowledge of the polymer property values involved in the heat equation (thermal conductivity, specific heat and heat transfer coefficient).

So we present a procedure to determine these thermal parameters easily in our environmental conditions of work without making a mechanical hypothesis, and without knowing the heat source distribution because we analyse thermal data as soon as the heat source is switched off.

In conclusion, we show an application involving a large strain mechanical test on a specimen of PC. The strain field is obtained by a mark tracking method. The energy balance has been calculated and associated with the volumetric deformation, showing the macroscopic and microscopic behaviour.
Internal Structure and Mechanical Properties of Glass Fibre Reinforced Pc/Abs Injection Mouldings with Different Fibre Surface Treatments
Authors: Mizoguchi Machiko , Umemura Toshikazu , Takasima Susumu , Otsuki Shinya , Yang Bin , Kuriyama Takashi , Leong Yew Wei , Hamada Hiroyuki
Published: September 2018

The microstructure (including the morphology, fibre length, and fibre orientation) of injection moulded glass fibre reinforced polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) blend was investigated. Three grades of commercially available surface treated glass fibres were used; each grade received a treatment that was specially formulated and optimized to enhance the affinity of the glass fibre surface to PC, ABS or both PC and ABS phases. Morphological evaluation confirms that the glass fibres had a preferential affinity to a particular resin depending on the type of surface treatment applied. This preferential affinity could also be detected through the difference in fibre length distribution in the specimens, although their mean fibre lengths and fibre orientations were quite similar. Flexural modulus, flexural strength and impact strength were all affected by differences in the distribution of fibre lengths. It was also discovered that the resin flowed faster than the glass fibres, especially at the core of the mouldings.
Molecularly Imprinted Polymer: Using the Template-Monomer Strategy towards a Highly Selective Sorbent
Authors: Zheng Mingxia , Li Songjun , Zhang Jianming
Published: September 2018

This article presents a fully-conceived work aiming at designing a highly selective sorbent by molecular imprinting. Based on the template-monomer strategy, the imprinted polymer was prepared by using bisphenol A (BPA) dimethacrylate as the polymerisable monomer. The binding framework was generated by releasing BPA from the polymer. Adsorption tests indicated that the prepared polymer can discriminate BPA well from its analogue dihydroxybenzophenone, so as to adsorb more of the former and less of the latter. Theoretical simulation additionally shows that adsorption by this polymer fits the Freundlich and Temkin models well, but not the Langmuir model. Related information indicates that these observations can be a result of induced molecular memory from the imprint.
Electrical and Mechanical Properties of Carbon Black -Filled Poly (Styrene-Co-Butyl Acrylate) Latex Reinforced Polyester Nonwoven Composites
Authors: Kumar M.N. Satheesh , Siddaramaiah
Published: September 2018

The main goal of the present research work was to fabricate lightweight nonwoven fabric impregnated composites for antistatic applications. Composites were fabricated by impregnating polyester nonwoven fabric with aqueous carbon black (CB) filled poly (styrene-co-butyl acrylate) latex. The effect of the amount of CB on the mechanical and electrical properties has been studied. Tensile strength, stitch tear strength and surface hardness were reduced by an increase in the wt.% of CB. The percentage elongation of the composites increased drastically because of the presence of diethylene glycol plasticiser in the CB dispersion. The dielectric constant, dissipation factor and loss factor of the composites increased with increasing wt.% of CB and decreased with increasing frequency. The reduction in dielectric properties with increasing frequency could be due to the delocalisation of charge carriers.
A New Method for Testing and Evaluating the Long-Time Resistance to Oxidation of Polyolefinic Products
Authors: Schröder Hartmut F. , Munz Martin , Böhning Martin
Published: September 2018

Oxidative long time resistance is essential for many polyolefinic products, especially if repair or exchange is not possible as encountered in many building applications.

For the time being, CE-standards for geosynthetics are covering the needs of a minimum lifetime of 25 years only, though many applications require longer lifetimes (up to 100 years and more).

Testing long time oxidation resistance is complicated by the complex interplay of physico-chemical processes and reactions in combination with the need for relatively short testing durations, usually not exceeding 12 months. Thus, for normal atmospheric oven testing the use of temperatures clearly higher than 80 °C is inevitable. It should be noted that Arrhenius extrapolation exceeding the temperature range of experimental data by more than 20 K requires the consideration of additional safety factors in order to allow for possible changes of the apparent activation energy EA. In general, at elevated testing temperatures care has to be taken that oxygen diffusion does not become the rate limiting process. Furthermore, in many application environments the loss of antioxidants (and other components) is - besides oxidative deactivation - mainly due to extraction by aqueous media and not due to evaporation. For oven testing, however, frequently the latter is the case.

With these limiting conditions in mind a test has been designed which in addition to elevated temperatures is accelerated by the presence of an increased oxygen pressure and a stirred aqueous medium. This enables us to perform durability tests at markedly lower temperatures with reasonable testing durations and significantly reduced diffusion limited oxidation (DLO) effects. Also it allows for physical and chemical impacts of aqueous media. Assessments of oxidative durability can be performed by autoclave immersion exposures at three different temperatures (usually 60, 70 and 80 °C) and 50 bar oxygen pressure and additionally at 80 °C and two different oxygen pressures (usually 10 and 20 bar).

Results of such accelerated tests are evaluated by means of modified Arrhenius equations with the application of a 3D-regression analysis. Validation of the method is still at an early stage, like for most other lifetime test methods. For purpose of comparison, materials of approved durability were used, such as pipe materials of quality PE100 and PE 80 with well-known minimum lifetime determined according to ISO/TR 9010, i.e. by long-term failure tests under internal hydrostatic pressure at different temperatures and by evaluation using the Arrhenius law.

Based on results of such tests it is supposed that a rather quick and relevant method is now at hand for testing the oxidation life of olefinic polymeric materials (like pressed plaques) or specimens of finished products like textiles, sheets, liners, pipes or composites. This test method should be very useful for the effective design of polymer formulations.
Incorporation of Silica Nanospherical Particles into Epoxy-Amine Crosslinked Materials
Authors: Torrens Francisco , Solar Lorena , Puchol Victoria , Latorre Julio , Abad Concepción , Campos Agustín
Published: September 2018

Composites of silica nanospheres coated with crosslinked epoxy–amine were synthesised and examined by 29Si-magic-angle-spinning nuclear magnetic resonance spectroscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy and scanning electron microscopy. The most representative fact is that epoxy-modified nanospheres lost less weight at high temperatures. At temperatures greater than 300°C the loss of weight for epoxy-modified nanospheres was rather lower than for unmodified nanospheres. This helped them to retain their structures, as the loss of weight can have adverse effects on network defects, due to the loss of crosslinks by unit of volume.
Characterization and Modeling of the Effect of Environmental Degradation on Interlaminar Shear Strength of Carbon/Epoxy Composites
Authors: Goruganthu Srikanth , Elwell Jason , Ramasetty Arun , Nair Abilash R. , Roy Samit , Haque Anwarul , Dutta Piyush K. , Kumar Ashok
Published: September 2018

Accelerated ageing experiments have been conducted to address durability issues of carbon/epoxy composites to be used for emerging facilities and infrastructure, such as, bridges and buildings, in different climatic zones. The degradation of carbon/epoxy composites under UV, hygrothermal exposure, and applied tensile stress has been investigated. The tests were designed to capture the synergistic effects of field exposure and extreme temperatures, viz., hot/dry, hot/wet, cold/dry, and cold/wet conditions. Short beam shear tests (SBST) were performed for the determination of interlaminar shear strength (ILSS) of conditioned composite specimens. The hot/dry samples showed increased strength, while the hot/wet ones showed a decrease in strength. It is conjectured that conditioning at 90 °C possibly contributed to an increase in the ILSS from post curing. For the hot/wet samples (90 °C, immersed in water) the results indicate that strength degradation due to moisture-induced hydrolysis overshadowed the post-curing effect. The samples subjected to shear stress under hot conditions (90 °C) showed a higher ILSS, possibly due to improved crosslink density arising from post-cure. There is insignificant variation in the ILSS of UV treated and the UV untreated control samples. All the SBST test data reported in this work are from tests performed at room temperature and ambient humidity after environmental ageing.

A two-dimensional cohesive layer constitutive model with a prescribed traction-separation law constructed from the basic principles of continuum mechanics, taking into account hygrothermal mechanisms that are likely to occur within a cohesive bi-material interface, such as between adjacent plies in a laminate, was applied to simulate interlaminar failure in the SBST specimens, using Finite Element Analysis (FEA). A phenomenological predictive model was developed using the finite element results.
Properties of Glass Laminates of Novolac Epoxy - Diallyl Bisphenol a - Bismaleimide Resins
Authors: Devi K. Ambika , Nair C.P. Reghunadhan , Ashari G. Viswanathan , Ninan K.N.
Published: September 2018

The high temperature properties of a novolac epoxy (EPN) – 2,2'diallyl bisphenol A (DABA) resin system was improved on co-curing it with bisphenol A bismaleimide (BMI). The concentration of BMI in the stochiometric blend of EPN and DABA was varied from 0.5 to 2.0 per equivalent of allylphenol. This ternary blend was used for processing glass laminates and their performance was evaluated through thermal, mechanical and dynamic mechanical characterisation. The incorporation of BMI in an epoxy-phenol system yielded a matrix system with comparable mechanical properties, improved high temperature stability and high temperature strength retention. The increase in BMI concentration beyond the stochiometric equivalent caused deterioration in mechanical properties including fracture toughness, and stress relaxation of the laminate. But the high temperature performance of the system evaluated through the interlaminar shear strength retention of their glass laminates showed systematic improvement with increase in BMI concentration. Toughening with polyethersulphone improved its mechanical properties, with a marginal penalty on its glass transition temperature.
Preparation of Natural Rubber/Eva/Montmorillonite Nanocomposites by Latex Compounding
Authors: Chuayjuljit Saowaroj , Nonthaboonlert Bongkoch , Limpanart Sarintorn
Published: September 2018

Nanocomposite materials of natural rubber (NR)/poly(ethylene-co-vinyl acetate) (EVA)/montmorillonite (MMT) were prepared by latex compounding without modification of the MMT. EVA and MMT were well mixed at room temperature in the latex state and subsequently blended with NR latex at NR/EVA dry weight ratios of 100/0, 90/10, 80/20, 70/30, 60/40 and 50/50. Where used, MMT was added at 4 parts per hundred of dry rubber and EVA (phr). The homogeneous latex mixture was then cast into sheets on a glass mold, air dried for 2 days at room temperature and then in an oven at 70 °C for 6 h. It was subsequently cured at 110 °C for 2 h. After curing, samples were examined for their structure and morphology by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), whilst tensile properties were investigated using a Universal Testing Machine. The XRD patterns and TEM images of the nanocomposites showed an exfoliated structure. The 90NR/10EVA/4MMT exhibited the highest tensile strength, with incorporation of MMT offering a substantial improvement in tensile strength. SEM micrographs revealed that the MMT particles were well dispersed in the polymer matrix. However, increasing the EVA content to 50 wt.% reduced the compatibility between NR and EVA.
Highly Fiber-Loaded Composites: Physical and Mechanical Properties
Authors: Nourbakhsh Amir , Ashori Alireza
Published: September 2018

The effect of coupling agent and fiber content on physical and mechanical properties of a lignocellulosic material-thermoplastic polymer composite was examined. Using poplar fiber as the reinforcing filler, polypropylene as the thermoplastic matrix polymer, and maleated polypropylene as the coupling agent, reinforced composites were prepared. In the sample preparation, three levels of fiber loading (55, 70 and 85 wt.%) and three levels of coupling agent content (0, 2 and 4 wt.%) were used. The mechanical strengths of the composites slightly increased as the fiber loading increased, but the physicomechanical properties were significantly improved with the addition of the coupling agent.
Fast Functionalisation of Polypropylene (Pp) by Ultraviolet Irradiation and Compatibilised Pp/Caco3 Composite
Authors: Deng Shushan , Ran Qianping , Wu Shishan , Shen Jian
Published: September 2018

Some oxygen-containing groups such as C–O and C=O were quickly introduced onto polypropylene (PP) chains by ultraviolet irradiation at high light intensity and high environmental temperature in air. The content of the groups increased with increasing time of ultraviolet irradiation. There was no gel in ultraviolet-irradiated PP. Compared with those of unirradiated PP, the crystal form and the phase space of ultraviolet-irradiated PP did not change, but its melt temperature decreased, and its crystallinity, liquidity and hydrophilicity increased. The ultraviolet-irradiated PP used as compatibiliser was melt blended with PP and CaCO3, and a PP/irradiated PP/CaCO3 composite was prepared. Compared with those of PP/CaCO3 composite, the compatibility and dispersion of the PP/irradiated PP/CaCO3 composite were improved, and its tensile strength and notched impact strength were increased.
Influence of Carbon Nanofiber Content and Surface Treatment on Mechanical Properties of Vinyl Ester
Authors: Plaseied A. , Fatemi A. , Coleman M. R.
Published: September 2018

This paper discusses the effects of carbon nanofiber surface treatment (purification and chemical functionalization) and carbon nanofiber volume fraction on mechanical properties of thermoset vinyl ester polymer nanocomposites under tensile and flexural loadings. Highly graphitic carbon nanofibers were surface treated by addition of functional groups to their surface, which provided a stronger composite as compared to conventional composites due to better bonding of the fibers to the polymer matrix. It was found that addition of up to 1 wt.% functionalized carbon nanofibers provided increases in mechanical properties over the addition of higher volume fraction of carbon nanofibers.
Mechanical Properties of Cost-Effective Polypropylene Composites Filled with Red-Mud Particles
Authors: Akinci A. , Akbulut H. , Yilmaz F.
Published: September 2018

In recent years, the use of filler materials, such as red mud, in composites has increased. In this study, the use of industrial waste red mud as a filler material in an isotactic polypropylene (iPP) polymer–matrix composite (PMC) was investigated. A variety of mechanical tests were performed on the unreinforced polymer and on composites with 10, 20, 30, 40 and 50 wt.% red mud. Tensile strength, three-point flexural strength and hardness tests have been carried out, and the relationships between the red-mud content and properties were examined. Scanning electron microscopy (SEM) was applied to the fractured surfaces after three-point flexural tests. The results showed that, while the values of tensile and flexural strength were decreased, the hardness was increased with increasing red-mud content.
Influence of Epoxy Nature on the Properties of an Epoxy– Diallylbisphenol A–Bismaleimide Matrix System
Authors: Devi K. Ambika , Nair C.P. Reghunadhan , Sadhana R. , Ninan K.N.
Published: September 2018

The ternary matrix system comprising a reactive blend of epoxy, diallylbisphenol A, and bisphenol A bismaleimide (EPB) was found to be comparable with the epoxy–phenol (EP) system in terms of its mechanical properties, and superior to it in terms of its high-temperature performance. The influence of structural variations of the epoxy resin on the thermal, physical, and mechanical properties of the ternary blend was examined. EPB compositions were prepared using a combination of bisphenol A bismaleimide and diallylbisphenol A with three different epoxy resin systems, namely novolac epoxy (E1), bisphenol A diglycidyl ether (E2), and tris(4-glycidyloxyphenyl)methane (E3). Cure characterisation of these reactive blends (EPB–E1, EPB–E2 and EPB–E3) was carried out using IR spectroscopy, differential scanning calorimetry, and rheological analysis. The trend in their thermal stability, based on the temperature of the onset of decomposition, is EPB–E3 > EPB–E1 > EPB–E2. The mechanical properties – compressive, flexural, and interlaminar shear strength – of the glass composites of these matrices were found to depend on the epoxy structure. The higher crosslink density of the trifunctional epoxy improved the high-temperature properties of the system. The ternary system served as a very good adhesive, where its strength as well as its retention at high temperature increased in proportion to the functionality of the resin. In general, the maximum strength values were observed for the system containing the novolac epoxy.
Tailoring the Mechanical Performance of Epoxy Resin by Various Nanoparticles
Authors: Liu Sheng , Zhang Hui , Zhang Zhong , Zhang Taihua , Sprenger Stephan
Published: September 2018

Flexible organic elastomeric nanoparticles (ENP) and two kinds of rigid inorganic silica nanoparticles were dispersed respectively into a bisphenol-A epoxy resin in order to tailor and compare the performance of mechanical properties. It was found that the well-dispersed flexible ENP greatly enhanced the toughness of the epoxy with the cost of modulus and strength. Comparatively, the rigid silica nanoparticles improved Young's modulus, tensile strength and fracture toughness simultaneously. Both fumed and sol-gel-formed nanosilica particles conducted similar results in reinforcing the epoxy resin, although the latter exhibited almost perfect nanoparticle dispersion in matrix. The toughening mechanisms of nanocomposites were further discussed based on fractographic analysis.
Compressive Strength of FRP-Confined Concrete at Elevated Temperatures
Authors: Al-Salloum Y.A.
Published: September 2018

Many research studies have shown that fibre-reinforced polymers (FRPs) can be efficiently, economically, and safely used for strengthening and rehabilitation of reinforced concrete structures. However, relatively little is known about the behaviour of FRP materials at high temperature, and this is a primary factor that is limiting the widespread application of FRP materials in civil engineering structures. This paper presents the results of an experimental programme to investigate the effect of high temperature on the performance of concrete cylinders externally confined with fibre-reinforced polymer (FRP) sheets. For this purpose, 42 small-scale concrete cylinders measuring 100 × 200 mm were cast. Of these 42 specimens, 14 specimens were left unwrapped to be used as baseline or control specimens, 14 specimens were wrapped with one layer of CFRP sheets, and the remaining 14 specimens were wrapped with GFRP sheets. These specimens were exposed to room temperature and heating regimes of 100 and 200 °C for a period of 1, 2, and 3 h. The specimens were tested in compression, and their performance was evaluated after they had been exposed to specific heating regimes. The test results demonstrate that, at a temperature around the glass transition temperature (Tg) of the resin, CFRP- and GFRP-wrapped specimens experienced a small loss of strength, resulting from melting of epoxy. This damage was more pronounced when the temperature reached 200 °C.
Residual Stresses Characterization of Laminated Composites Curing by FEM and FBG Sensor
Authors: Guo Zhan-Sheng
Published: September 2018

The residual stresses and developed mechanisms of residual stresses during manufactured thermoset composites were considered. The relative importance of the different mechanisms was analyzed. The residual stresses were determined by linear viscoelastic model and measured by the fiber Bragg grating (FBG) strain sensor. The theoretical results and experimental measurement were agreed well. It was found that the viscoelasticity of composite laminates should be considered when residual stresses were calculated during composite curing. FBG strain sensor could be used to measure the residual stresses and was reliable.
Effect of Multi-Walled Carbon Nanotubes Addition on Mechanical Properties of Polymer Composites Laminate
Authors: Yip Ming-Chuen , Lin Yi-Chieh , Wu Chung-Lin
Published: September 2018

Carbon nanotubes (CNTs) have high potential for the modification of glass-fiber reinforced polymer (GFRP) composite laminates. This paper reports the fabrication of CNTs/GFRP composite laminates using ultrasonication and the hand lay-up method. The aim of this study is to investigate the interlaminar shear strength (ILSS) and flexural strength of composites consisting of several different proportions of CNTs. When CNT content is 0.75 percent hundred resin (phr), the mechanical properties are the best. The ILSS was significantly improved 15.7% and flexural strength improved 9.2%. The effects of addition of CNTs on the mechanical performances were evaluated with respect to retention of high-temperature properties up to 200 °C. It was found that ILSS, flexural strength and bending modulus were significantly enhanced by CNTs at different temperatures. Dynamic mechanical analysis (DMA) was employed to measure the storage modulus of composite laminates. To consider the effect of temperature on GFRP and CNTs/GFRP composite laminates, the results showed the trends in the temperature-dependence and were nearly identical to the ILSS, flexural strength, bending modulus and dynamic properties. The experimental fracture surfaces were also observed by scanning electron microscopy (SEM). Significant weakening of fiber-matrix interface and matrix softening were major factors affecting the strength and modulus reduction at high temperature.
Experimental and Theoretical Study on Interfacial Bond Performance between CFRP and Concrete under Static and Moving Load
Authors: Yong-chun Cheng , Ping Jiang , Feng He , Ya-feng Gong
Published: September 2018

The interfacial bond strength between carbon fiber reinforced polymers (CFRP) and concrete is a very important factor for the strengthening effect of CFRP. According to the test, the change law of shear stress and the damage process of epoxy bond are investigated under static and fatigue load in the paper. At the same time, the analytical calculation models of interfacial shear stress and strain at arbitrary points are established, therefore the static and fatigue bond strength can be calculated by the analytical models. Contrasting analysis indicates that the results of calculation models coincide with the tests, which shows that the results of analytical models are favorable. Moreover the model can also be used to analyze and predict the interfacial stress of the composite structure. It is also applicable for the other composite structures, which suggests that this method possesses practical significance for the reliability analysis of the interfacial bond strength.
Internal Friction of TiNi Shape Memory Alloy Wires/Epoxy Composites Measured by Dynamic Mechanical Analysis
Authors: Chang S.H. , Han J.L. , Lee C.Y. , Liu G.L.
Published: September 2018

Internal friction of TiNi wires/epoxy composites were investigated by dynamic mechanical analysis (DMA) in this study. TiNi wires/epoxy composite and neat epoxy both show significant Tg transition peaks with tan δ above 0.40 at around Tg temperature and lower internal friction peaks with tan δ below 0.06 at around -40 °C. The internal friction peaks at lower temperature is attributed to the crankshaft motion of the glyceryl-like groups in diglycidyl ether of bisphenol A. TiNi wires/epoxy composite also possesses two B19'→R and R→B2 martensitic transformation internal friction peaks at around room temperature with tan δ about 0.04 The peak temperatures of the Tg transition and the low temperature peaks of the TiNi wires/epoxy composites increases with the increase of applied frequency and their activation energies are calculated as 419.1 and 48.7 kJ/mole, respectively. Embedding TiNi wires into epoxy matrix can enhance the Young's modulus and ultimate strength of the composite.
Dynamic Analysis of Sandwich Plates with a Constraining Layer and a Magnetorheological Fluid Core
Authors: Li Yu-Hang , Fang Bo , Li Feng-Ming , Zhang Jia-Zhong , Li Song
Published: September 2018

The dynamic analysis of rectangular plate with a magnetorheological fluid core and a constraining layer is investigated. The dynamic equations of the sandwich plate are derived using finite element method. The natural frequencies and loss factors of the sandwich plate with different varying parameters are studied in this paper. When the magnetic field intensities increase, the frequencies will increase and the loss factors will reduce. With the thickness of MR layer increasing the frequency will get down at first and then go up rapidly. Furthermore the effects of MR core layer thickness on modal loss factors and thickness of constraining layer are discussed in this paper.
The B-basis Value of the Shearing Strength of Triangle-Shape Carbon Fibers Reinforced Plastics
Authors: Liu Xin , Wang Rongguo , Liu Wenbo
Published: September 2018

Triangle-shape carbon fiber is a kind of new carbon fiber. Its special cross-section endows the triangle-shape carbon fibers reinforced plastics (TCFRPs) with different characteristics from circle-shape carbon fibers reinforced plastics. In this paper, the shearing strength of TCFRPs was studied by statistical method including detecting outliers, k-sample Anderson-Darling test, estimating the shape and scale parameters of a Weibull distribution, and goodness-of-fit test. Finally, the B-basis value of TCFRPs shearing strength was investigated by mathematical statistics method and calculated by MATLAB.
The Higher Order Crack Tip Fields for Arbitrary FGM Composite Functions
Authors: Yao Dai , Lei Zhang , Jun-feng Liu , Xiao Zhong
Published: September 2018

As the material properties function at the crack tip greatly affects the structure of crack tip field, especially in the study of comparatively thin FGM composites whose properties functions are equipped with the feature of high gradient variation, it is not enough to adopt the simple linear function to depict the property testpoints of the material. A new method, which is more precise to deal with the experimental data and to depict FGM composite properties functions (e.g. elastic modulus E), is proposed in this paper. Beside the linear function, quadratic term, cubic terms and so on are added. Then, the solution is first given for the general power function, and the more precise analytical solution of higher order crack tip fields will be obtained by means of superposition method. Actually, any other complicated or arbitrary material functions can be treated similarly by using Taylor series expansion at the crack tip. Finally, the obtained higher order crack tip fields or the eigen-functions which can depict the arbitrary material function would provide the theoretical basis for the fracture experiments and numerical simulation, and this method is of great universal significance.
Dynamic Responses of Composite Marine Propeller in Spatially Wake
Authors: Hong Y. , He X.D. , Wang R.G. , Li Y.B. , Zhang J.Z. , Zhang H.M. , Gao X.
Published: September 2018

Dynamic responses of a composite marine propeller in spatially wake were investigated in this paper. A hydroelastic model was developed to identify the response characteristics of the composite propeller blades using a finite element method (FEM) coupled with a computational fluid dynamics (CFD) method. Rotational effects and added mass were considered. A coupled matrix was established and solved by the Newton-Raphson numerical procedure. The dynamic characteristics and responses of the composite blade were calculated and compared with those of the counterpart rigid blade. Effects of various parameters, including the layer lamination and fiber orientation were investigated.
Simulating Effective Engineering Elastic Constants of the Stator Core Lamination
Authors: Zhonghai Xu , Xiaodong He , Zhihe Li , Di Wang , Rongguo Wang
Published: September 2018

In this paper, we study the problem of effective engineering elastic constants of stator core lamination of water turbogenerator. The three-dimensional transformations of elastic constants of composite lamina between the principal material coordinate system and the reference coordinate system are given, then the stator core lamination is modeled as the composite laminate and by utilizing the thick laminated plate model, we determine effective engineering elastic constants of the stator core lamination. Finally, a simple example is included to demonstrate the validity of the model and the programme codes.
Preparation and Properties of Self-healing Microcapsules Containing an UV-curable Oligomers of Silicone
Authors: Xing Rui-ying , Zhang Qiu-yu , Sun Jiu-li
Published: September 2018

In this work a new series of microcapsules for self-healing coatings were successfully prepared by an in-situ polymerization route with poly (urea-formaldehyde) (PUF) as a shell material and a mixture of methacryloxypropyl terminated dimethyl silicone oil (2MA4000) and 1-hydroxycyclohexyl phenyl ketone (I-184) as core materials. The UV curing properties of the core materials were performed by the gel yield. The surface morphology and shell wall thickness, the particle size and distribution, and the chemical structure and properties of microcapsules were characterized by SEM, FTIR, laser particle size analyzer and thermogravimetric analysis (TGA). The results indicated that the gel yield of 2MA4000 with 3 wt.% Irgacure-184 was 63.35%. The spherical microcapsules (particle size of mostly 20-50 μm) were produced with a relatively thin shell wall of 20-90 nm, a filling content of 84 wt.%, and a high yield of 71.4 wt.%. The microcapsules exhibit a good heat resistance. The core of the microcapsule was under a good preservation state during the encapsulated process, and part of the core which was in the interface between oil and water participated in the reaction of urea and formaldehyde. It makes the microcapsule wall being the organosilicon modified PUF resins, which promotes the thermostability of the microcapsule wall and compatibility with organosilicon coating.
Correlation Analysis of Heat Transfer, Cure and Mechanical Behavior of Fiber Composite Laminates
Authors: Wang Xiaoxia , Jia Yuxi , Wang Chengguo
Published: September 2018

Curing deformation is a direct consequence of resin thermal curing induced composite internal stress. The understanding of the curing process is crucial to predict the internal stress, and then effectively control the curing deformation. For this purpose, the thermal-chemical-mechanical modeling of the multi-physical process is done, and a new simulation procedure is presented. Then a new correlation analysis of the heat transfer, cure and mechanical behavior of fiber composite laminates is performed. It is shown that the temperature and curing degree distributions are inhomogeneous. The temperature of the geometrical structure center is higher than that of the surface because of the exothermic reaction and the low thermal conductivity of the composite, so are the resin elastic modulus and the resin shrinkage strain. The research is helpful for understanding the complicated thermal-chemical-mechanical relationships, and then the design of composite curing processes according to certain requirements can be implemented.
Thermally Curable Poly(silylacetylene)siloxane as Polymeric Precursor of SiC Ceramic
Authors: yu Chengda , Wang Mingcun , Li Pi
Published: September 2018

The pressureless pyrolysis of poly(silylacetylene)siloxane precursor to silicon carbide (SiC) was studied. Poly(silylacetylene)siloxane was synthesized via organometallic condensation. The precursor resin was well soluble in acetone, toluene and tetrahydrofuran (THF), etc. Thermal cure was conducted readily at 180-250 °C to form a hard brittle solid, and the cure mechanism was radical polymerization of ethynyl groups. The ceramic yield of pyrolysis at 1500 °C was at about 67 wt.%. The molar ratio of Si/C in the SiC was found at 1:1.1-1:3 based on elements analysis. The results of x-ray diffraction (XRD) revealed the typical β-SiC structure in the poly(silylacetylene)siloxane derived ceramics.
The Influence of Thermal Fatigue on the Properties of Glass Fiber/Epoxy Composites
Authors: Wang Dongzhi , Zhou Xinrui , Ge Heyi , Liu Zhiyong , Liu Huashi , Sun Kangning
Published: September 2018

In this paper, glass fiber reinforced epoxy composites were prepared according to laminated plates design principles by using glass fiber/epoxy composite prepreg. The mechanical property of glass fiber/epoxy composite and water absorption have been investigated before and after thermal cycles. Thermal cycles were performed in the temperature range between −40°—80°. Through different thermal cycles (0, 60, 120, 180 cycles), it was found that the mechanical property of different ply of glass fiber/epoxy matrix composites was decreased and water absorption of composites were increased. Moreover, scanning electron microscopy (SEM) was used to characterize the fracture morphologies of glass fiber/epoxy composites before and after thermal cycles. SEM images showed that after 180 thermal cycles, the bonding effect of glass fiber and epoxy matrix interfacial layer became worse and pores increased, leading to the decrease in the mechanical properties and the increase in the water absorption.
Preparation of Styrene and Butyl Acrylate Emulsion with High Solid Content in the Presence of a Polymerizable Emulsifier
Authors: Feng Ying , Zhou ChunHua , Liu Wei , Xiao RenXing
Published: September 2018

An emulsifier-free emulsion was synthesized via the preemulsified emulsion polymerization, with styrene (St), butyl acrylate(BA), and ammonium allyloxtmethylate nonylphenol ethoxylates sulfate (DNS-86) as the polymerizable emulsifier. The influences of the reaction temperature and time, DNS-86 amount on the emulsion polymerization were investigated, then the most suitable polymerizing conditions were obtained, the semi-continuous method was used, T=80°, t = 5 h, the dosage of DNS-86 was 2% of total monomers mass. The analysis of the profiles of IR, NMR, and Laser particle size demonstrated that the copolymerization occurred between St, BA and DNS-86 to generate P(St-BA-DNS-86) successfully, and hydrophilic sulfonic groups containing the copolymer were conducive to emulsion stability. Besides, the influences of the dosages of DNS-86 on the latex solid content and average particle size were discussed. The result showed that with the increase of DNS-86 amount, the latex solid content increased and average particle size of latex reduced, e.g., at the 2% mass amount of DNS-86 52.50% of the latex solid content, 78 nm of average diameter, 0.0379 of particle size distribution. Latex of high solids of up to 62.1% has been obtained with 5% DNS-86. The results of TEM showed that the copolymer emulsion with smaller particle size and uniform distribution could be obtained by using polymerizable emulsifier DNS-86.
A New Type of Flame Retarded Epoxy Resin Based on Metal Phosphinates
Authors: Liu Xueqing , Liu Jiyan , Sun Shan , Chen Jia
Published: September 2018

Exolit OP930 (abbreviate OP930) product based on aluminum (diethyl phosphinate) is a new class of flame retardants for the use in epoxy resin (EP). In this paper, the mechanical properties, the morphologies of fracture surfaces, thermal stability, glass transition temperature (Tg) and flame retardant of OP930-EP composites with different composition have been studied. The composites exhibit satisfying thermal properties and a high limiting oxygen index (LOI) value as well as good compatibility with the matrix. Compared to neat resin, the mechanical properties of composites are also on a very good level.
Comparative Analysis of Stress Distribution of Braided Composites under Different Load Conditions
Authors: Qu Peng , Jia Yuxi , Nie Jiaqi , Guan Xiaojun
Published: September 2018

In this paper, a comparative analysis of microscopic stress distribution in braided composites under different load conditions has been performed using a numerical method. The complexity of the architecture in non-orthogonally braided composites leads to the difficulty in the study of microscopic stress field. A geometric model which is suitable for the description of the stress distribution has been established. The location and magnitude of stress peak under different loads were investigated and the stress concentrations were subsequently discussed. For in-plane load, the maximum stress appears at ‘joint part’ of main bearing tow; for out-plane load, at ‘overlapped part’. These results are beneficial to detecting the damage initiation regions. The effect of braid angle on in-plane shear deformation is more intensive relative to the in-plane tension, whereas the influence is inconspicuous for the out-plane load. The comparative analysis is help for a thorough understanding of the mechanical properties of braided composites.
Deformation Measurement of Composite Laminate with Impact Damage under Compressive Loads
Authors: Ruan Jiangtao , Wang Shibin , Tong Jingwei , Shen Min , Aymerich F. , Priolo P.
Published: September 2018

The out-of-plane displacement fields for a cross-ply laminate [03/903]s with impact damage under axial compression are investigated using carrier electronic speckle pattern interferometry (carrier-ESPI) in this paper. The compression after impact (CAI) test is conducted on rectangular specimen 65mm × 87.5mm in size using an anti-buckling fixture. In order to apply a uniform load to the top of composite laminate, a self-designed device insures that an accurate loading is given. The experimental results reveal the deformation characteristics of laminate under CAI test.
Composite Nanoparticles on the Natural Rubber Latex Glove for Reduction of Surface Friction and Cytotoxicity
Authors: Kanjanathaworn N. , Kaewsaneha C. , Polpanich D. , Jangpatarapongsa K. , Tangboriboonrat P.
Published: September 2018

Poly(methyl methacrylate) (PMMA) particles were deposited via the Layer-by-Layer technique onto sulphur prevulcanized natural rubber latex film grafted with polyacrylamide (SPNR-g-PAAm). Besides an increase in surface hardness and roughness, hence, decrease of the surface friction of SPNR glove, a direct contact between skin and rubber film was reduced. Consequently, it was expected that the allergic problem to certain sensitive individuals and cytotoxic potential caused by the leachable non-rubbers (proteins) and lubricant powder sprinkled onto SPNR glove would be lowered. The SPNR and SPNR-g-PAAm coated with PMMA particles were extracted by using the culture medium and subjected to the in vitro cytotoxicity evaluation on L-929 fibroblasts. Results showed that the cytotoxicity was effectively reduced by coating PMMA particles onto the grafted rubber film. In order to improve both the binding ability with SPNR and antimicrobial activity, the PMMA-chitosan core-shell particles were prepared for further depositing onto the non-grafted SPNR film. Moreover, the nanocapsules containing an aqueous core of disinfectant agent (chlorhexidine digluconate) and poly(methyl acrylate) or sulphur prevulcanized skim rubber shell were prepared for being embedded in SPNR glove.
A Novel Beam Model for Mode-II Delamination Analysis of Composite Laminates
Authors: Han Haitao , Lu Zixing , Zhang Jordan Zheng
Published: September 2018

A two dimensional beam model is proposed for delamination analysis of composite laminates, where Timoshenko's plane cross-section assumption is abandoned, and the longitudinal displacement of the beam is proposed as continuous functions of the transverse and the longitudinal coordinates, to match shear deformations. Moreover, the composite laminate is modeled as upper and lower sub-beam through the delamination interface, and corresponding conditions for interface sliding are satisfied through a generalized variational theory. The accuracy of the results of this analytical model is verified by comparison with those from three dimensional finite element models. Furthermore, the influences of delamination depth, length, central position and modulus mismatch ratio ( E1/ E2) of the upper and lower sublaminate to the energy release rate are discussed.
Wear Properties of Carbon/Epoxy Resin Composites with an Interpenetrating Network Structure Derived from Artificial Sponge
Authors: Wang Tianchi , Kong Song , Wong Chingping
Published: September 2018

Artificial sponge was used as the template to produce carbon/epoxy resin composites with interpenetrating network structure. Carbon with a network structure was first obtained by the pyrolysis of sponge. The composites were then obtained by injecting epoxy resin into the carbon. Their microstructures and wear properties were analyzed. The results show that the structure of sponge controlled the interpenetrating network structures of the carbon/epoxy resin composites. The carbon-network in the composites was shown to stabilize the coefficient of friction of epoxy resin. The carbon also reduces the wear rate of the epoxy resin remarkably.