bluuebunny/crossref_metadata_2025 huggingface dataset:
Advanced Composite Applications in the Construction Industry
Authors: Tunali Ayşe
Published: September 2018

Composites offer the designers a combination of properties not available in traditional materials. In addition to the use of composite material in the construction itself it has also gained momentum in the product that complete construction. For example, composite materials have been used in products that are used in bathroom (sink, closet, urine, faucet, seat) or that are used as ceramic coating material (wall tile, floor tile, porcelain stoneware tile). New advanced surface functionalities such as easy to clean, self-cleaning, anti-fingerprint, anti-slip, anti-bacterial, anti-microbial, stain resistance, wear resistance, scratch resistance have attracted much recent interest in the scientific community. In order to design these new surfaces nano materials and/or composite materials indispensable. The ultimate goal of this study is to present examples of these new functional products.
Effect of the Blending Process and Filler Loading on the Mechanical Properties of Silica-Filled Sbr/Br Compounds
Authors: Ni Luping , Wang Jibin , Xu Haiyan , Wu Chifei
Published: September 2018

The effects of the blending process on the mechanical properties of styrene butadiene rubber/cis-butadiene rubber/silica systems was studied in relation to the order of addition of two kinds of rubbers during blending. The specific blending method of two-step rubber feeding method led to different mixing conditions, and consequently the mechanical properties of the vulcanizates varied significantly. The blending process was mainly influenced by two factors: the wetting of the filler and the interactions of the materials. This work focused on the influence of filler loading on different blending methods, in order to build up the relationship between bound rubber and various properties in silica filled SBR/BR compounds.
Furan-Based Narrow-Band-Gap Copolymers for Red Light-Emitting Diodes and Bulk Heterojunction Photovoltaic Cells
Authors: Sun Mingliang , Wang Li , Yang Renqiang , Zhang Bin , Yang Wei
Published: September 2018

A series of conjugated copolymers (PFO-DFQ) derived from 2,3-dimethyl-5,8-difuran-2-yl-quinoxalines (DFQ) and 9,9-dioctylfluorene (DOF) were prepared by the palladium-catalyzed Suzuki coupling reaction with molar feed ratios of DFQ around 1%, 5%, 15% 30% and 50% respectively. The obtained polymers were readily soluble in common organic solvents. The absorption spectra of the copolymers ranged from 300 nm to 560 nm, with two absorption peaks at around 390 nm and 480 nm, both in solution and thin film. The photoluminescence (PL) emission peaks were in the region from 465 nm to 611 nm in thin solid films. The electroluminescence (EL) emission peaks were from 550 nm to 712 nm, depending on the DFQ content. Bulk heterojunction photovoltaic cells fabricated from composite films of PFO-DFQ copolymers and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as electron donor and electron acceptor respectively, showed power conversion efficiencies 0.13% with open-circuit voltage (Voc) of 0.60V and short-circuit current density (Jsc) of 0.68 mA/cm2 under AM1.5 solar simulator (100 mW/cm2).
Rheological, Thermal and Dynamic Mechanical Studies of the Ldpe/Perlite Nanocomposites
Authors: Sahraeian R. , Esfandeh M. , Hashemi S.A.
Published: September 2018

Nanocomposites based on low-density polyethylene (LDPE) and nano perlite were prepared at various perlite contents via melt mixing in a twin-screw extruder. Rheological measurements, dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA) tests were carried out on the nanocomposites. The results confirmed the establishment of interactions between LDPE matrix and treated nano perlite. In addition, dynamic mechanical properties and thermal stability of the treated nanocomposites were improved.
Modified Pet Fibres for Metal Ion and Dye Removal from Aqueous Media
Authors: Abdouss Majid , Shoushtari Ahmad Mousavi , Shamloo Nasrin , Haji Aminoddin
Published: September 2018

In this study, poly(ethylene terephthalate) (PET) fibres were modified with methacrylic acid (MAA) to provide new chelating fibres. Benzoyl peroxide (BPO) was used as initiator. To increase the grafting yield, a pretreatment with formaldehyde was done, which increased the efficiency of grafting treatment by connecting –CH2OH groups to the fibres' polymeric chains. The effect of reaction parameters including methacrylic acid concentration, benzoyl peroxide concentration, reaction time and temperature on grafting yield were studied. The extent of fibre modification was characterized with FT-IR spectroscopy, thermo-gravimetric analysis (TGA) and SEM. The ability of modified fibres to adsorb Cu2+ and Pb2+ ions from aqueous media was determined using atomic absorption spectroscopy. The results confirmed that the methacrylic acid grafted PET fibres could remove Cu2+ and Pb2+ ions from water efficiently.

Also, the modified fibre was used for basic dye adsorption from water and showed a great capacity for removal of cationic dyes from aqueous media.
Material and Process Related Influences on the Particle Based Inductive Heating of High Density Polyethylene
Authors: Bayerl Thomas , Mitschang Peter
Published: September 2018

Recently, a new inductive heating method to process fibre reinforced polymer composites was introduced. This method uses particulate susceptors which are affected by an electromagnetic field. The innovative heating method can be used to heat up bulk as well as sheet like materials because the generated thermal energy is distributed intrinsically in the component. Since the heating performance was observed to be closely related to the used susceptor material, other important factors influencing the heating and polymer melting were investigated in an experimental series. The study comprised materials-related parameters, such as filler fraction and particle size, as well as process-related ones, like induction current, coupling distance, and frequency. High density polyethylene (HDPE) doped with different susceptor materials, ferromagnetic as well as electrically conductive, was used for the heating experiments.

The observed influence on the analyzed heating performance of some materials and process parameters could be derived from standard physical laws, in particular the dependence on coil current and the coupling distance. Other process parameters, like the susceptor size and the frequency, were identified to have a more complex relationship on the heating ability. Cast iron particles, which showed the best heating performance in the study, were able to melt the applied HDPE within 90 seconds at a filler fraction of only 5 to 10 wt.%. For future applications of this heating method, a theoretical approach was revealed to deliver a sufficient approximation of the inductive particulate heating in a finite element model.
Chemical and Mechanical Properties Studies of Chinese Linen Flax and Its Composites
Authors: Huo Shanshan , Ulven Chad A. , Wang Haoran , Wang Xinnan
Published: September 2018

To improve the mechanical performance of flax polymer composites, different surface modifications on flax fibres have been investigated by many researchers. In this study, the effects of alkaline treatment on the properties of Chinese linen flax were evaluated by different chemical and mechanical test techniques. Chemical detergents, stains and FTIR were used to investigate the chemical constituent changes in the Chinese linen flax. Moreover, the elastic properties of untreated and treated flax fibres were evaluated using a single fibre bundle tensile test. The elastic properties of their composites were accessed also using tensile tests. In addition, the theoretical elastic properties of alkaline treated flax were calculated using Halpin-Tsai equations. The theoretical elastic properties of flax/vinyl ester composites were also obtained to compare against the experimental results. An optimal/ultimate elastic modulus of flax/vinyl ester composites was predicted.
Interfacial Interaction between Polycarboxylate-Based Superplasticizer and Cement Component Minerals
Authors: Yu Yinhui , Liu Jiaping , Ran Qianping , Qiao Min , Gao Nanxiao
Published: September 2018

This paper is presented for a better understanding of the interaction between polycarboxylate-based superplasticizer (PCA) and cement component minerals. The impact of PCA on the particle interaction among tricalcium silicate (C3S), dicalcium silicate (C2S) and the initial Portland cement hydrates ettringite (AFt) has been systematically examined. The zeta potential was highly dependent on the chemical composition of the solvent. Furthermore, it was demonstrated that adsorption always occurred between the minerals and anionic PCA in spite of their equal charge sign. For silicates (including C3S and C2S), the adsorption of high load Ca2+ formed a positive layer and subsequently adsorbed anionic PCA. For AFt, the direct adsorption onto AFt results from its strong electrostatic interaction. The high affinity of PCA to aluminate phase surface can be attributed to the high reactivity of tricalcium aluminate and its large specific surface.
Electrospun Ultrathin Poly(vinyl alcohol) Fibre Assemblies Modified by Means of Polycarboxylic Acid / Sodium Hypophosphite
Authors: Schramm Christian , Rinderer Beate , Tessadri Richard
Published: September 2018

A viscous solution consisting of poly(vinyl alcohol) (PVA), butane-1,2,3,4-tetracarboxylic acid (BTCA) and sodium hypophosphite monohydrate (SHP) has been prepared and subjected to an electrospinning process in an attempt to produce BTCA-crosslinked ultrathin PVA fibre mats. At elevated temperatures the carboxyl groups of BTCA react with the hydroxyl groups of PVA via a five-membered cyclic anhydride thus forming ester linkages. The measurement of the fibre diameters of the electrospun fibres created at various high voltages (10, 15, and 20 kV) revealed that the diameters of the fibres were in the range of 0.98 - 1.20 μm. Single layer and double layer fibre assemblies were prepared and thermally treated at 180 °C.

The as-prepared ultrathin PVA fibre assemblies were analyzed by means of scanning electron microscopy (SEM), indicating that the morphology of the fibres had been changed. Fourier transform infrared/attenuated total reflection spectroscopy (FT-IR/ATR), X-ray powder diffraction (XRPD) and physical properties, such as water vapour absorption (WVA), water vapour transmission (WVT) and tensile strength were evaluated. The incorporation of BTCA resulted in an increase of WVA and a decrease of WVT. The tensile strengths of the cured PVA mats were remarkably decreased, when BTCA/SHP had been added.
Thermal Analysis of Highly Filled Composites of Polystyrene with Lignin
Authors: Barzegari M. Reza , Alemdar Ayse , Zhang Yaolin , Rodrigue Denis
Published: September 2018

This paper focuses on the thermal properties of polystyrene/lignin composites over a wide range of lignin content. Blending with and without a compatibilizer (styrene/ethylene/butylene copolymer) was performed in an internal batch mixer to prepare samples between 0 and 80%wt of lignin. From the compounds, an extensive thermal study was performed, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). TGA results indicated that the thermal stability of polystyrene increases with increasing lignin content. DMTA analysis showed higher storage modulus and lower loss factor with increasing lignin content for the range of temperature studied (30-150 °C). DSC results showed that the lignin/PS composites have a single Tg which is close to that of polystyrene. The addition of a compatibilizer up to 2%wt was found to improve the storage modulus of lignin/PS composite, especially at low temperature. Finally, scanning electron microscopy micrographs were used to show the state of interfacial adhesion or compatibility between lignin particles and the polystyrene matrix.
Analysis of Marching-modulus Rubber Rheograms
Authors: Farid Ahmed S. , Arunashanthi K. D.
Published: September 2018

Rheometry is widely used throughout the rubber industry to characterise the cure behaviour of rubber mixes. Industrial rheometers produce continuous traces or rheograms in which torque is plotted as a function of time as a rubber progressively cures. Rheograms in which a distinct maximum or steady-state value is obtained within a reasonable time present few problems when the main objective is to determine optimum vulcanisation times. Nevertheless, some rubber mixes display cure profiles that do not exhibit steady-state values within acceptable time scales; taking extremely long periods of time to do so. Running rheometers over prolonged periods in order to attain flat or steady state cures is neither productive nor economical. In such situations, it is desirable to develop a methodology whereby steady-state values can be estimated from short running times. Assuming that cure advances by way of first-order kinetics a graphical technique is introduced enabling the steady-state torque value to be estimated from short running times. The steady-state torque value obtained from the graphical procedure was compared with experimental values; poor agreement was found being within about 11%. Notwithstanding the poor agreement between the steady-state torque value observed experimentally and that predicted by the graphical method we nevertheless continue to recommend the use of the graphical technique. Our justification for the use of the graphical method is that the procedure provides reliable rate constants for the incipient stages of vulcanisation without having to determine full extents of cure. The rate constant determined by the graphical procedure was in good agreement with typical values reported in the literature7 thus affording credibility to our graphical methodology. As further confirmation as to the reliability of our technique, an analytical method introduced by Rigby2 was employed to verify the authenticity of our results. Comparison of our results with those ascertained from the analytical method showed reasonable agreement. In order to account for the significantly large difference between the graphically-estimated and experimental steady-state torque value, the ideal and simplistic assumption that curing proceeds by first order kinetics throughout the entire curing period was abandoned. Instead, it was assumed that the crosslinking process comprises two concomitant first-order curing reactions; notably normal and slow crosslinking reactions. The kinetic expression describing the two simultaneous vulcanisation reactions in terms of rheometry parameters is: [Formula: see text] where Tt is the torque at time t; Ta is the minimum torque; ti is the induction time; T¥,c and T¥,sc are the steady-state torque values for the normal and slow crosslinking processes respectively; and, kc and ksc represent the first-order rate constants for the normal and slow crosslinking processes respectively. Excellent agreement was found between the experimental steady-state torque value and that predicted by the composite kinetic expression.
Application of Taguchi Method in Optimizing Fabrication of Composite Panels for Interior Dividing Walls
Authors: Velosa J. , Rana S. , Santos T. , Fangueiro R. , Ramos L.
Published: September 2018

In order to save material and energy, an increased growth can be noticed in recent times in the use of low-cost and light-weight solutions for the interior dividing walls of buildings. In this context, the main aim of the present research work was to develop light-weight composite panels based on non-woven fabrics for this application as an alternative to more commonly used materials and to optimize the manufacturing process parameters in order to maximize their mechanical performance. Thermo-bonded nonwoven geo-textiles made from polyester (70%) and polypropylene (30%) fibres were consolidated using compression moulding technique, varying the various structural and process parameters, such as number of layers, compression time, temperature and pressure. Taguchi method was used to design the experiments, as well as to understand the influence of various parameters on tensile and flexural strengths of developed composite panels and to optimize them in order to maximize these properties. According to the analysis, a consolidation temperature of 210°C, pressure of 30 bars, compression time of 35 minutes and 30 layers are required to achieve the maximum values of tensile and flexural strength with minimum variability.
The Synthesis and Properties of Novel Conducting Polyaniline and Poly [(nitrile butadiene-co-acrylonitrile)/Polyvinyl Chloride] Blends
Authors: Alero-Koroma Dickson , Abbas Zaid Kahtan , Barton Stephen J. , Foot Peter J.S.
Published: September 2018

Thin films of the blends of dodecylbenzenesulfonic acid (DBSA) doped polyaniline (PAni) and the commercial poly(butadiene-co-acrylonitrile)/poly(vinyl chloride) blend (ZeonNipol®DN171) were prepared via co-dissolution, at varying ratios of conducting fillers (0.5-50 wt.%). Electrical conductivity measurements showed an increase in conductivity with increasing concentration of PAni-DBSA. At a percolation threshold of 0.9% (wt/wt), an increase in electrical conductivity of approximately four orders of magnitude ensued, with a recorded conductivity of 1.21 × 10-4 S.cm-1 for the most conductive blend (consisting of 50 wt.% PAni-DBSA). Characterization by UV-visible spectroscopy indicated retention of the doped (conductive) state of the PAni-DBSA in each elastomeric blend. Morphological studies by optical microscopy showed the presence of PAni-DBSA agglomerate networks (or interpenetrating networks) at higher concentrations; however, at low concentrations of PAni-DBSA, the dispersion and encapsulation of the conductive species was observed. Due to the double-phase morphology of Nipol® DN171, the encapsulation phenomenon may be attributed to the presence of the thermoplastic poly(vinyl chloride). Solubility parameter calculations confirmed the compatibility of PAni-DBSA with the constituents of the Nipol® DN171 elastomer. This was supported by the infrared spectra, which showed the presence of functional groups specific to the reacting components of each blend. Thermal analysis, by DSC and TGA, indicated an increased thermal stability with increasing concentration of the elastomeric material.
Effect of Temperature on the Thermal Conductivity of Wood-Plastic Composites
Authors: Bourai Karim , Riedl Bernard , Rodrigue Denis
Published: September 2018

The thermal conductivity of wood-plastic composites in the solid and molten state (between 25 and 180 °C) is reported for polyethylene filled with pine wood flour (0 to 20%). The experimental data are compared with a simulation model to determine the effect of wood concentration. The results show that thermal conductivity decreases with increasing wood concentration in the solid state. Nevertheless, the effect becomes negligible in the molten state. The simulation model was found to give good prediction at low wood levels, but moves away from the experimental values when concentration increases.
Titanium Dioxide Dispersed on Cellulose Acetate and its Application in Methylene Blue Photodegradation
Authors: de Campos Elvio A. , de Campos Sílvia D. , Roos Andreine A. , de Souza Bruna V. C. , Schneider Jean M. , Uliana Marciano B. , de Oliveira Rafael C.
Published: September 2018

A cellulose acetate/TiO2 composite was prepared by dissolving cellulose acetate in acetone:acetic acid (70:30 in volume) and adding quantities of titanium(IV) tert-butoxide to obtain varying oxide content after phase inversion, which was achieved by adding water to this mixture. Regardless the quantity of titanium(IV) tert-butoxide, were obtained composites containing about 4 wt.% of TiO2 as anatase, indicated by XRD and Raman spectroscopy. They showed thermal stability up to 250 °C. Adsorption isotherms of methylene blue revealed a maximum adsorption of 11 μmolg-1. This material proved to be an efficient catalyst for the photodegradation of MB under artificial or solar ultraviolet radiation.
Effects of Expandable Graphite and Modified Ammonium Polyphosphate on the Flame-Retardant and Mechanical Properties of Wood Flour-Polypropylene Composites
Authors: Guo Chuigen , Zhou Lin , Lv Jianxiong
Published: September 2018

In this work, the effect of both the expandable graphite (EG) and ammonium polyphosphate modified with 3-(methylacryloxyl) propyltrimethoxy silane (M-APP) on the flame retardancy and mechanical properties of the wood-polypropylene composites (WPC) were studied. Cone calorimetry results indicated that both EG and M-APP could effectively improve the flame retardancy of WPC, while the retardancy of EG was better than that of M-APP. When the flame-retardant loading was 25 wt.%, the limiting oxygen index (LOI) values of M-APP-filled WPC (M-APP/WPC) and EG-filled WPC (EG/WPC) were 30.7% and 37.9%, respectively. According to the LOI test, the optimal ratio of M-APP to EG in WPC was 1:1 by weight, at which the LOI value of WPC was 39.3%. Thermogravimetric analysis (TG) results indicated that the addition of M-APP and EG to WPC could lead to an increase of char residue. Under the same conditions, the char residue of composite filled with the mixture of EG and M-APP (at a ratio of 1:1) was greater than that of composites filled individually at the same temperature. Both the tensile strength and flexural strength decreased at a certain extent due to incorporation of EG into WPC, but with the addition of the M-APP, the mechanical properties of these composite samples increased. At the ratio of 1:1 (M-APP to EG), the mechanical properties of the composite were not obviously decreased, and the flame retardancy was higher than the M-APP-filled WPC composites.
Processing and Characterization of Continuous Fibre Tapes Co-Moulded with Long Fibre Reinforced Thermoplastics
Authors: Thattaiparthasarathy K. Balaji , Pillay Selvum , Bansal Dhruv , Ning Haibin , Vaidya Uday K.
Published: September 2018

An important advantage when designing with plastics is the ability to incorporate features such as ribs, grids and bosses in the part. Rib stiffened polymer matrix composites have been widely used in aerospace, automobile, and civil infrastructure applications due to their high impact and fatigue resistance, high strength and stiffness to weight ratio, and damage tolerance. However, for long fibre-reinforced polymer composites, the processing complexity increases for features including ribs, grids and bosses. An innovative method of replacing ribs is the use of pre-consolidated continuous fibre reinforced thermoplastic (CFRT) tapes that can be co-moulded with long fibre thermoplastics (LFT). This work focuses on processing and performance evaluation in terms of the static and dynamic properties of LFTs co-moulded with pre-consolidated CFRTs, referred to as endless long fibre thermoplastic (E-LFT). The E-LFT approach is an alternative to rib stiffened composites. The effect of the thickness and fibre type in tape reinforced LFT is compared to LFT (with and without ribs) of equivalent flexural rigidity for static flexure and low velocity impact (LVI) response. In all these conditions, E-LFT samples performed better that the LFTs with and without ribs. LFT samples with and without ribs exhibited a brittle failure, as opposed to the progressive failure exhibited by E-LFT.
Improvement in Mechanical and Thermo-Mechanical Properties of Carbon fibre/Epoxy Composites Using Carboxyl Functionalized Multi-Walled Carbon Nanotubes
Authors: Salam M.B.A. , Hosur M.V. , Jahan N. , Rahman M.M. , Jeelani S.
Published: September 2018

Investigations were carried out to optimize mechanical and thermal performances of carbon fibre/epoxy composites modified with functionalized carbon nanotubes. For fabricating carbon fibre/epoxy nanocomposites, 0.1-0.4 wt.% carboxyl-functionalized multi-walled carbon nanotubes (MWCNTs-COOH) were incorporated in an epoxy system. Laminates were cured at a temperature of 65.55 °C. The effects of MWCNT on flexural, interlaminar shear strength (ILSS),tensile and thermo-mechanical properties of carbon fibre/epoxy composites were studied. The results obtained from flexural, ILSS, tensile and dynamic mechanical analysis (DMA) of carbon fibre/epoxy demonstrated a linearly increasing trend in properties up to 0.3 wt.% MWCNT loading. Results obtained from the thermal mechanical analysis showed a linearly decreasing trend in coefficient of thermal expansion up to 0.3 wt.% MWCNT loading. The properties were lower at 0.4 wt.%, due to agglomeration that may have resulted in poor wetting of the carbon fibres.
Fabrication, Structural Morphology and Thermal Energy Storage/Retrieval of Ultrafine Phase Change Fibres Consisting of Polyethylene Glycol and Polyamide 6 by Electrospinning
Authors: Cai Yibing , Zong Xue , Ban Heng , Liu Qian , Qiao Hui , Wei Qufu , Zhao Yong , Fong Hao
Published: September 2018

This study aimed at the development and characterization/evaluation of polyethylene glycol (PEG) encapsulated in supporting polymer matrices (e.g., electrospun nanofibres) as innovative form-stable phase change materials (PCMs) for storage and retrieval of thermal energy. Ultrafine phase change fibres consisting of PEG (acting as phase change materials) and polyamide 6 (PA6, acting as supporting materials) were successfully fabricated by electrospinning technique. The effects of PEG amount and two different molecular weights (Mn) of PEG on structural morphology and thermal energy storage/retrieval property of PEG/PA6 ultrafine phase change fibres were systematically studied by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), respectively. The SEM images showed that neat PA6 nanofibres were smooth with cylindrical shape, but the tubercles and/or beads in fibres were observed for PEG/PA6 ultrafine phase change fibres with increasing PEG amount and higher molecular weight of PEG. The average fibre diameters ranged from about 80 to 150 nm and increased with increasing the PEG amount and molecular weight of PEG, which resulted from the increased viscosity and decreased conductivity of composite spin dopes. The DSC results indicated that the enthalpies of melting and crystallization of PEG/PA6 ultrafine phase change fibres increased with increasing PEG amount, and were lower than those of neat PEG powders.
Short Nylon 6 Fibre Reinforced Polystyrene/Natural Rubber Blends: Effect of Maleated-Polystyrene Compatibiliser
Authors: Jayalatha G. , Kutty Sunil K.N.
Published: September 2018

Nylon 6 short fibre was used to prepare composites based on blends of 85/15 Polystyrene (PS)/Natural rubber (NR) to study the effects of surface modification of the fibres and a compatibiliser based on PS. Initially, the loading of fibre, cut to 6 mm length, was varied from 0 to 3 wt.% in a 85/15 PS/NR blend. The composites were prepared on a Thermo Haake Rheocord mixer at 170 °C and sheeted out on a two-roll mill. Tensile, flexural and impact test samples were punched out from sheets and tested to study the mechanical and dynamic mechanical properties. It was found that the tensile properties, flexural properties and impact strength increased with the fibre content up to 1 wt.%, above which there was a significant deterioration in the properties. The fibre surface was further modified by alkali treatment and a reactive compatibiliser based on maleic anhydride-grafted-polystyrene (MA-g-PS) was used in an effort to improve the performance of the composites. The treated Nylon fibre in conjunction with the compatibiliser improved the tensile properties, flexural properties and impact strength. Dynamic mechanical analysis showed that by using the modified fibre and the compatibiliser, the storage modulus of the composite could be significantly improved. The fibre-matrix morphology was studied by SEM analysis of the tensile fractured specimens. Examination of the fibre extracted from the treated fibre composites revealed that some fraction of the matrix was bonded to the fibre surface. These results suggest that a combination of hydrolysed fibre and MA-g-PS increases the interfacial adhesion between the fibre and the matrix.
Effect of Rapid Compression on the Crystallization Behaviour of Polyethylene
Authors: Zhuo Ranran , Shao Chunguang , Li Qian , Liu Chenggang , Zhang Ruijing , Zhang Yang , Cao Wei , Shen Changyu
Published: September 2018

The crystallization behaviour of PE samples with different molecular weight was investigated through two different processes, concerning rapid compression (RC) and quench cooling (QC). The scanning electron micrographs, wide angle X-ray diffraction and Raman results showed that all the recovered samples were composed of spherulites. For the QC process, the effect of molecular weight on the spherulites morphologies was slight, but for the RC process, with increased molecular weight (MW), the growth rate as well as the final average diameter of the spherulites decreased remarkably. Additionally, for samples with the same MW, the mass fraction of the rigid amorphous phase of RC samples was lower. Furthermore, the crystallinity distributions in the longitudinal and latitude directions of the RC samples were both more uniform than those of the QC samples, implying that in the RC process, the pressure distribution was quite uniform and there was no pressure decay.
Fiber Bragg Grating Sensors for Fatigue Monitoring of Composite
Authors: Guo Zhan-Sheng , Feng Jiemin , Wang Hui , Hu Hongjiu , Zhang Junqian
Published: September 2018

Fiber Bragg grating (FBG) sensor can be used to monitor the mechanical behavior of composite. The internal strain of composite during a constant stress amplitude fatigue testing process was monitored with FBG sensors in this paper. FBG sensor as a fatigue indicator can reveal the decrease of Young's modulus of the specimen, which is a direct index of damage. FBG sensor can not only be embedded in composite laminates to detect fatigue damage, but also has excellent durability compared with other sensors such as electric strain gauge. After 1 million cycles, the FBG sensor can still keep good sensibility. FBG sensor as a fatigue indicator is a novel sensor to monitor, evaluate and give crash alert for the health state of composite during its whole service life. And also, a new and simple model of stiffness degradation was developed. This model can be used to predict the fatigue life of composite material.
Study on Cure-Induced Residual Stresses for Fibre Metal Laminate
Authors: Guangquan Yue , Jiazhen Zhang , Songhe Meng
Published: September 2018

During autoclave curing process, because of the mismatch between coefficients of thermal expansion of fibre layers and metal layers, residual stresses are developed in Fibre Metal Laminates (FML). In this paper, a three-dimensional finite element model was developed to predict cure-induced residual stresses for FML. And then FML-2/1 and FML-3/2 structures (plate and L-shape) were studied with the finite element model. The results show that residual tensile stress is in metal layers and residual compressive stress is in fibre layers. Residual stresses in Fibre Metal Laminates are bigger enough to affect the deformation and fatigue performance.
Finite Element Analysis of the Fatigue Crack Tip Parameters in the Glass Fiber Reinforced Aluminum Alloy Laminates under Tension-Compression Loading
Authors: Shigang Bai , Jiazhen Zhang , Yu Sha , Zhengong Zhou
Published: September 2018

Elastic–plastic finite element analyses have been performed to study the compressive stress effect on fatigue crack growth of the glass fiber reinforced aluminum alloy laminates (GLARE) under applied tension–compression loading. The crack opening displacement and plastic zone size were obtained for the aluminum layer in GLARE. The differences of parameters near the crack tip under tension-compression and tension-tension loading were observed. The results have shown that the displacement and reverse plastic zone size continue to change with the applied compressive stress. Based on the finite element analysis results, a fatigue crack propagation model of GLARE has been proposed.
Numerical Analysis of Bird Impact on a GLARE Plate
Authors: Fu Liu , Jiazhen Zhang , Zhongmin Hu , Mingyi Zhang
Published: September 2018

GLARE is a “Glass Fibre Reinforced Epoxy/Aluminum FMLs (Fibre Metal Laminates)” and has been reported for its excellent impact resistance. In this paper, a numerical model for bird impact on an aluminium alloy plate was established, using the explicit finite element code PAM-CRASH first. A corresponding bird impact experiment was carried out and the simulations were compared with the experimental results. The good agreement between them confirms the accuracy of the numerical analysis model, including the Smoothed Particle Hydrodynamics (SPH) bird model and the aluminium alloy constitutive model. In the second part of the paper, another simulation on a thinner 2024-T3 aluminum alloy plate was performed, which was used to determine the critical bird impact speed for the plate. By combining the Johnson-Cook model for aluminum alloy and Continuum Damage Mechanics (CDM) theory for the glass fibre reinforced composites, a constitutive model for GLARE was derived. Impact simulations on the GLARE plate with the same thickness and impact speed as the 2024-T3 plate shows no penetration on the GLARE plate and indicates that GLARE can effectively improve the impact resistance of a structure.
Tensile Behavior of Hybrid Plain Woven Fabric Laminate Repaired by Scarfing Method
Authors: Sui Liu , Zhidong Guan , Xia Guo , Jianhua Chen , Guofen Xi , Jing Cai
Published: September 2018

Experimental investigation on tensile behavior of hybrid plain woven fabric laminate repaired by scarfing method was conducted in the paper. There were 3 types of specimens with scarf ratio of 1:10, 1:20 and 1:30, respectively. Tests results indicated the tensile strength of repaired laminate increasing with scarf ratio and the specimen with the scarf ratio of 1:30 has the highest tensile strength which could reach 103.2% of the intact laminate strength. Besides, distinct differences were observed on failure mode of specimens with different scarf ratio. For specimen with scarf ratio of 1:10, damage initiated and propagated in repair zone while failure occurred outside repair zone for 1:30 specimen. A finite element model was developed with ABAQUS to simulate tensile behavior of repaired specimens. The calculated results were in good agreement with test results. Based on the numerical model, influence of scarf ratio to stress distribution in adhesive, ultimate tensile strength and failure mode of repaired laminate was discussed. Results of the investigation provide insight into scarfing repair design method on hybrid plain woven fabric laminate.
From Aminolysis Product of Pet Waste to Value-Added Products of Polymer and Assistants
Authors: Zhang Ling-na , Liu Li-zhu , Yue Qun-feng , Zhu Chun-cheng
Published: September 2018

In this work, the aminolysis depolymerization of poly(ethylene terephthalate) PET was carried out with ethanolamine and several acetates as catalysts. The main product, bis(2-hydroxyethyl) terephthalamide (BHETA), was identified from FTIR and 1H NMR. It was found that PET depolymerization is favoured by increasing temperature, time and catalysts. Results shown that under present conditions of aminolysis, the conversion of PET was 100% and high yield of BHETA. Moreover, aminolysis products have the potential to undergo further reactions to yield secondary value-added product, such as unsaturated polyesters, polyurethanes, epoxy resin hardeners and non-ionic polymer surfactants.
Pipe Stiffness Prediction of Buried Gfrp Flexible Pipe
Authors: Park Joon-Seok , Hong Won-Hee , Lee Wan , Park Jung-Hwan , Yoon Soon-Jong
Published: September 2018

In this paper, we present the result of investigations pertaining to the pipe stiffness (PS) of glass fiber reinforced polymer plastic (GFRP) flexible pipes buried underground. PS formula for the parallel plate loading condition is derived based on the elasticity theory. Vertical and horizontal displacements are also derived. In the study, the mechanical properties and structural behavior of GFRP flexible pipes are investigated experimentally and the results are used in the analysis and design of these flexible pipes. Pipe stiffness of GFRP flexible pipe is investigated by the parallel plate loading test, the finite element analysis, and theoretical analysis. The results of pipe stiffness of the GFRP flexible pipe obtained by the experiment, theory, and the finite element analysis are compared and close agreements are observed.
Numerical Simulation of the Mode I Fracture of Angle-Ply Composites Using the Exponential Cohesive Zone Model
Authors: Zhu Guowei , Qu Peng , Nie Jiaqi , Guo Yunli , Jia Yuxi
Published: September 2018

The cohesive zone model (CZM), which is based on the elasto-plastic fracture mechanics, is nowadays widely used in the numerical simulation of the composites ductile crack and progressive delamination. For the sake of tracking the angle-ply composites delamination evolution accurately, the exponential CZM is applied. At first the standard double cantilever beam (DCB) specimen is modeled using the exponential interface damage law to verify the feasibility of it. The simulated results are in good agreement with the analytical results and corrected beam theory. Then in order to investigate how the ply angle influences the mode I fracture, five laminates with different ply orientations, [012/012], [012/3012], [012/4512], [012/6012] and [012/9012], are studied. The main results are obtained as follows. The delamination evolutions corresponding to different ply angles are quite non-uniform. The unidirectional laminate exhibits the stable, continuous crack growth along the specimen, so does the [012/9012] specimen. Whereas the other three specimens show very uneven fracture surfaces. When the plies change from [012/012] to [012/9012], the stiffness along the specimen is gradually reduced correspondingly, so are the distance of the delamination propagation and the peak load, while the corresponding loading displacement increases slowly. The research provides the numerical simulation method to evaluate the multidirectional laminated composites fracture toughness, and then to optimize the composite performance by the design of ply angles.
Mechanical Properties and Fracture Behavior of Dual-Curable Epoxyacrylate Composites Filled with Different Functionalized Silica Particles
Authors: Su Yu-Chieh , Wang Chung-Yih , Don Trong-Ming
Published: September 2018

To investigate the interfacial effect on properties of epoxyacrylate-silica composites, sub-micron silica particles were synthesized by sol-gel reaction in an ammonia/ethanol solution and their surfaces were endowed with different functional groups by reaction with several silanes including 3-methacryloxypropyl trimethoxysilane (MPTMS), vinyl trimethoxysilane (VTMS), 3-glycidoxypropyl trimethoxysilane (GPTMS) and 3-aminopropyl trimethoxysilane (APTMS). Except the APTMS-modified silica particles due to its severe aggregation, the modified silica particles with size ranging from 150∼250 nm were then added to the pre-synthesized difunctional epoxyacrylate resin at a concentration of 15 phr, in addition to the photo- and thermo-curing agents. Tensile mechanical properties and the fracture toughness were all increased by adding the silica particles into the epoxyacrylate. Particularly, the composite filled with the MPTMS-modified silica particles (EA-MPS15) had the best performance. The reason is that the vinyl double bond of the MPTMS on the surface of the silica particles could took part in the curing reaction of the epoxyacrylate, thus providing strong interfacial chemical bonding between the silica particles and the polymer matrix and also improving the dispersion of the silica particles. The increase of fracture toughness was due to the crack deflection and particle-matrix debonding as evidenced by SEM pictures on the fracture surface.
Thermal Analysis of a Novel Tetrafunctional Epoxy Resin Cured with Anhydride
Authors: Zhou Z.W. , Yu M.M. , Bai R.C. , Li A.J. , Sun J.L. , Ren M.S.
Published: September 2018

The viscoelastic behavior and thermal property of 3, 3'-diethyl-N, N, N', N'-tetraglycidyl-4, 4'-diaminodiphenylmethane (C2H5-TGDDM) epoxy resin in presence of methyl nadic anhydride (MNA) as curing agent and 2-ethyl-4-methyl imidazole (2,4-EMI) as accelerator were investigated by dynamic mechanical thermal analysis (DMTA) in single cantilever mode at different frequencies and non-isothermal DSC-TGA, respectively. According to the DMTA data, the results show that the storage and loss moduli and loss factor curves were shifted to higher temperatures region with increasing frequencies. The value of glass transition temperature (Tg) is in the range of 224 °C to 247 °C, and the difference between the Tg determined by the loss modulus and loss factor peaks is ca. 15 °C, and the glass transition activation energy was calculated. The results of DSC-TGA show that the curing and the decomposition heat-release peaks of epoxy resin were occurred at ca. 191 °C and 360 °C, respectively. The onset temperature of degradation is 324°C, and the epoxy resin system was heat-resistant.
Ratcheting Behaviors of the Carbon Biber Reinforced Peek Composites: Experimental Study and Numerical Simulation
Authors: Zhu Zhiwu , Liu Xu , Li Xiangyu
Published: September 2018

In this study, uniaxial tensile tests were performed on the polyether ether ketone (PEEK) resins and the carbon fiber/polyether ether ketone (CF/PEEK) composites. The ratcheting behaviors of the CF/PEEK composites under stress-controlled cyclic loading were studied by using a combined experimental and finite element approach, with a particular emphasis on the effects of mean stress and stress amplitude. Based on the constitutive relation parameters obtained from the uniaxial tensile tests, the representative volume element model of the CF/PEEK composite was established by using ABAQUS and the random sequence of adsorption (RSA) algorithm. The experimental and numerical simulation results were compared under the same loading conditions. It was showed that a noticeable ratcheting occurred in the composites under the asymmetric stress-controlled cyclic loading and was positively related to the stress amplitude and mean stress. A good agreement between the experimental and simulation results was achieved in this study. Therefore, the finite element simulation is a useful method to predict the ratcheting strains of the CF/PEEK composites under different conditions.
Damage Effects of Charged Particles Irradiation on An Epoxy Resin
Authors: Gao Yu , Dong Shangli , Bao Jianwen , Guo Yang , Lu Shaowei
Published: September 2018

In this study, the mass loss effect and the related outgassing of 5224 epoxy resin have been investigated. Subsequent irradiation of 160 keV proton and electron with the fluences ranging from 5.4×1015 to 3.75×1016 cm−2 in vacuum (1.2×10−5 Pa) was performed. The increase of the fluence of proton or electron made the mass loss ratios increase, then level off. The surface roughness of specimens increased followed by augmenting as the function of fluence. The outgassing rate of most molecule ions reached to maximum under the fluences ranging from 5.4×1015 cm−2 to 1.18×1016 cm−2. With further increasing fluence, the outgassing rate decreased owing to the effects of carbon enrichment or even carbonification developed gradually on the surface layer of the irradiated specimens. It is suggested that two events might play vital roles in dominating the magnitude of the outgassing rates: one is the formation of molecule ions; the other is the enrichment of carbon on the surface layer.
Investigation of the Interface Parameters of Fiber-Reinforced Composite Materials
Authors: Xie Zhimin , Chai Dongliang , Weng Yanyan , Du Haiwen
Published: September 2018

Design of the interfacial properties is a significant fundamental issue in the field of composite materials. Much attention has been paid to the improvement of the interface strength, while there has been a little work concerning the mechanical design of the interface for fiber-reinforced polymers (FRPs) in which the fiber is transversely isotropic thanks to its orientation feature. Based on the conception of neutral inclusion and imperfect interface conditions, the interface parameters are obtained for the FRPs by using Kolosov constant. We demonstrate the effect of the thermal residual stresses on the neutrality for FRPs in this paper. If the interface has the properties of design parameters without consideration of thermal stress, the presence of thermal residual stress/strain would break the neutrality in the cases of equal-biaxial tension and pure shear. In particular, the neutral fiber does not exist unless the thermal stress is eliminated in the equal-biaxial tension. In the case of uniaxial tension, the neutral fiber does not exist in absence of thermal stress, while the neutrality would become possible by properly controlling the thermal residual stress. Because the large thermal residual stress will result in the formation of cracks in matrix, a trade-off design is necessary between the neutrality and the initiation of matrix cracking.
Modeling of Coupled Temperature-Displacement-Diffusion Problem for Silica-Phenolic Composite under High Temperature
Authors: Shi Shengbo , Liang Jun
Published: September 2018

Volume ablation process of resin-matrix thermoprotective composite is, generally, associated with complex physico-chemical changes, heat and mass transfer processes and irreversible changes of thermomechanical and thermophysical properties. The thermomechanical behavior of resin-matrix thermoprotective material during volume ablation can be analyzed as the coupled temperature-displacement- diffusion problem of porous elastomers under high temperature. Based on the ablative and thermoprotective mechanisms of silica-phenolic composite, the governing equations of the porous elastomers, such as equation of motion of solid phase, gas diffusion equation and energy conservation equation, were established. These governing equations were further modified using finite element method to obtain the element stiffness equation for each element. Additionally, the global stiffness equations were assembled and solved by Gaussian elimination method. The temperature distribution, pore pressure, strain and stress field in plane strain state were calculated when silica-phenolic composite was exposed to a constant radiant heat flux.
Characterization of Strength of Carbon Fiber Reinforced Polymer Composite Based on Micromechanics
Authors: Li Wangnan , Cai Hongneng , Zheng Jie
Published: September 2018

Micro-mechanics of failure (MMF) is a micromechanics-based failure criterion for composites, which can be applied to characterize the composite strength accurately and reliably. The strength and mechanical properties of unidirectional laminate are measured by the static tensile loading and compressive loading tests as well as three points bending test. The micromechanics model is proposed to amplify the detailed mechanical and residual thermal stresses for the key points in the fibers and matrix. The critical MMF parameters are characterized by using the stress amplification factors and the measured strengths of unidirectional laminate. The carbon fibers reinforced plastic UTS50/E51 is used to demonstrate the application of MMF theory. The failure envelopes are constructed and compared on the basis of the MMF theory and Tsai-Wu failure theory. The failure mechanism and static tensile strength of quasi-isotropic laminate of polymer composites is studied based on MMF. The UTS50/E51 CFRP is used to demonstrate the application of theory of MMF.