bluuebunny/crossref_metadata_2025 huggingface dataset:
FT-IR Studies on the Cyclization Reaction of Acrylic Fibres
Authors: Farsani Reza Eslami
Published: September 2018

In this paper, chemical structure of three different acrylic fibres containing itaconic acid (IA), sodium methallyl sulfonate (SMS) and sodium 2-methyl-2-acrylamidopropane sulfonate (SAMPS) comonomers were studied by Fourier transform infrared (FT-IR) spectroscopy. This study was conducted in order to find the effects of precursor type acrylic fibres on the chemical interaction during the stabilization and on the properties of fabricated carbon fibres.

The results of FT-IR show that the peaks related to C≡N bonds in acrylic fibres containing IA comonomer were completely removed during stabilization, while the peaks in SAMPS and SMS were just reduced. Also, the peak related to CH2 bond for acrylic fibres containing IA comonomer was reduced sharply in comparison with the other two fibres. These changes show that cyclization of nitrile groups and stabilization reactions in acrylic fibres having IA comonomer were completed. These reactions increase the tensile strength of carbon fibres produced from this material in comparison with other carbon fibres produced from acrylic fibres containing SAMPS and SMS.
Preparation and Characterization of a Phenol-formaldehyde Resin Adhesive Obtained from Bio-ethanol Production Residue
Authors: Qiao Wei , Li Shujun , Xu Fengying
Published: September 2018

Enzymatic hydrolysis (EH) lignin was utilized to replace phenol partially for preparing phenol-formaldehyde (PF) resin adhesives. The influence of the degree of lignin substitution on the properties of the lignin phenol-formaldehyde (LPF) resin adhesive was investigated. The results demonstrated that up to 50% of phenol in the resin could be replaced by EH lignin without damaging the bonding strength of the adhesive, and a lower free phenol content was observed in LPF resin adhesives. Fourier transform infrared spectroscopy spectra of the resins revealed that the introduction of lignin did not appreciably change the final chemical structure of the adhesive, but did negatively impact the resin's thermal ultimate stability. Furthermore, compared to bio-ethanol production residue-modified phenol-formaldehyde (ERPF) resin, the LPF resin exhibited higher bonding strength at the same level of the phenol substitution. This result of the comparison indicated that the raw biomass extraction process improved the performance of the bio-based PF resin.
The Design Optimisation of the Co-extrusion of a Wood-like Grain Surface Composite Polymer Profile
Authors: Qi-bing Wang
Published: September 2018

A wood-like grain surface composite polymer profile (or wood-like profile) was fabricated by the extrusion moulding of melting multi-component polymers through a co-extrusion die, with two extruders feeding the co-extrusion die simultaneously. To improve the extrusion velocity uniformity of melting composite polymers, and decrease the distortion of wood-like grain profiles, this study treats the velocity equality among sub-regions in the wood-like profile cross-sections at the exit of the co-extrusion die as its optimisation objective. Meanwhile, the compression section gap, which exerts a significant influence on flow uniformity is selected as the design variable. Finite element numerical simulation and an ERP system are adopted to optimise the design in combination with a CAD/CAE network system co-extrusion die expert database of concurrent engineering. The optimisation design of case studies confirms that the velocity uniformity of the optimised wood-like grain profile melts presents a significant improvement in each sub-region at the exit of the co-extrusion die. Moreover, the distortion of composite profiles is decreased. The structural dimensions and performance of the composite profiles meet industrial demands.
Carbon Fiber/epoxy Interfacial Bonding Improvement by Microwave Pretreatment for Low-energy Electron Beam Curing
Authors: Zhao Xinming , Duan Yugang , Li Dichen , Zhang Jingjing , Wang Ben
Published: September 2018

In this paper, the prepreg of carbon fiber/epoxy (CF/EP) was pretreated by microwave radiation, and the effect of microwave radiation on the interfacial performance of the composite cured by low-energy electron beam (E-Beam) was investigated. By a rather short time microwave irradiation, the atomic ratio of O/C on the CF surface was increased, so did the oxygen-containing functional groups which helps strengthen the chemical bonding between the fiber and resin matrix. The CF surface became rougher after the microwave radiation, which would improve the bonding surface and mechanical interlocking. Compared with the untreated composite, the interlaminar shear strength (ILSS) of laminate fabricated with microwave radiated prepreg was increased by 9.6%. The SEM images showed that the resin distributed uniformly and adhered to the CF surface tightly. The interlaminar shear fracture morphology by SEM further indicated that the bonding strength between CF and EP resin was effectively improved by the microwave radiation.
Dynamic Compressive Behavior of FRP-Confined Concrete under Impact and a New Design-Oriented Strength Model
Authors: Hui Yang , Hengwen Song
Published: September 2018

The dynamic mechanical properties of fiber-reinforced polymer (FRP) confined concrete were experimentally and theoretically studied using a 100-mm-diameter split Hopkinson pressure bar (SHPB) apparatus. As test results turned out, the dynamic strength of FRP-confined concrete was improved significantly. Within the mean strain rate range of 50–130 s−1, the dynamic strength increased with the rise in strain rate. With same strain rate, the strengthening effect was influenced by confining ratio. The optimal confining ratio of AFRP-confined concrete is 0.264, once beyond this limit, the failure pattern will be changed, and the dynamic strength will be decreased. In addition, a modified model was proposed for dynamic strength of FRP-confined concrete, which agrees with the test results well.
Morphological, Mechanical and Thermal Properties of Chemically Bonded Graphene Oxide Nanocomposites with Biodegradable Poly(3-hydroxybutyrate) by Solution Intercalation
Authors: Bian Jun , Lin Hai Lan , Wang Gang , Zhou Qiang , Wang Zheng Jun , Zhou Xing , Lu Yun , Zhao Xin Wei
Published: September 2018

Chemically covalent bonded graphene oxide (MGO)/Poly(3-hydroxybutyrate) (PHB) nanocomposites were fabricated successfully through solution blending. Morphological observations indicated that MGO was dispersed well in the nanocomposites during solution intercalation. The mechanical and thermal property characterizations indicated that incorporation of 2.0 wt.% MGO resulted in the increasing of up to 101% and 46% in tensile strength and tensile modulus of nanocomposites, respectively, compared to neat PHB; while the maximum thermal decomposition temperature improved about 15.5 °C higher than that of PHB. Differential scanning calorimetric (DSC) analysis showed that the crystallization process of PHB accelerated, resulting in an increasing in crystallinity with the incorporation of MGO due to its’ “ nucleating effect”. Electrical conductivity analysis indicated that the electrical conductivity of MGO/PHB nanocomposites has increased by 14 orders in comparison to that of pure PHB, especially for r-MGO filled PHB nanocomposites (4 wt.% r-MGO loading). It was concluded that the formation of graphene-graphene network structure in the nanocomposites, the increases in homogeneous dispersion of graphene and interfacial interactions contributed to the enhancements of properties.
A Study on Degradation of Composite Material PBS/PCL
Authors: Huang Jitao , Cui Chunna , Yan Guiyang , Huang Jianhua , Zhang Min
Published: September 2018

A systematic study on the degradation and mechanism of composite materials based on polybutylenes succinate/ polycaprolactone (PBS/PCL) was conducted by putting composites of different ratios into the local soil culture solution and cured compost culture solution to observe the microbial reaction. The surface morphologies, crystallinities, and structures of the composites before and after degradation were characterized by FTIR, XRD, and SEM. The results revealed that the original functional groups of the composites were retained perfectly after the mixing and fusing of PBS and PCL, and hydrogen bonds were formed between these two phases. The composite based on PBS and PCL degraded well in the compost culture solution. The weight of this composite was reduced by 32.67% after 60 d. Degradation of the composite in the soil culture solution was indicated by a weight loss up to 8.76%. PCL degraded much faster than PBS did, while the PBS/PCL composite degraded even faster. Crystallinity was improved after degradation, and the non-crystalline area degraded first. The viscosity analysis showed that the degradation of the composite was achieved by the simultaneous processes of breaking big molecules into small molecules and by the degradation of small molecules.

Biodegradable and environmental friendly PBS that belongs to aliphatic series polyester is one of the most promising environmental-friendly and biodegradable polymer materials; PCL is a kind of thermal plastic crystalline polyester with good bio-degradability, drug permeability, and biocompatibility. Meanwhile, the raw materials for PCL preparation are cost-effective and accessible. Due to the wide application of bio-degradable materials, the relationship between the degrading rate and the molecule design of bio-degradable material is becoming a key research topic in the area of biodegradable materials1–10. Zhang et al. studied the relationship between the chemical structure of PBS and its degradable structure11–16; the influences of microorganism quantity, humidity, temperature, metal ions, and pH on the degradable property were also studied17–21. In addition to the factors mentioned above22–26, adding other materials also greatly influences degradation performance. In practical applications, the mechanical properties of biodegradable materials are not as good as conventional plastics; the uncontrollable degradation rate of the biodegradable materials is another issue that prevents their wider promotion.

In this project, PBS/PCL composites of different ratios were prepared. Good mechanical properties and good biodegradability were expected for these composites. A systematic study on the degradation of these composites is presented, which provides good reference for the controllable application of biodegradable plastics. Furthermore, the degradation mechanism of the composites is rationally inferred, which is well supported by reported data. This study facilitates further research on the controlling of degrading rate of PBS/PCL.
Defects Characterization in CFRP Using X-ray Computed Tomography
Authors: Liu Xueshu , Chen Fei
Published: September 2018

Although carbon fiber reinforced plastic (CFRP) is ideally high mechanical performance, manufacturing induced defects are hardly avoidable and their appearances generally result in a loss of mechanical properties. To accurately characterize this kind of defects is a foundation to estimate mechanical performance of a CFRP structure. Compared to the traditional defect assessment methods, X-ray computed tomography (CT) has been approved a promising method due to its ability to provide spatial information of defect. In this study, the effect of resolution on the accuracy of defects estimation was investigated in details. Scanning data obtained by using two different resolutions were comparatively studied based on delamination characterization. In addition, an image processing based method for porosity estimation was discussed as well. It is concluded that it is possible for us to enlarge our region of interest by selecting a reasonable resolution not at cost of losing too much desired details.
Curing Process-induced Internal Stress and Deformation of Fiber Reinforced Resin Matrix Composites: Numerical Comparison between Elastic and Viscoelastic Models
Authors: Wang Xiaoxia , Zhao Yaru , Su Hao , Jia Yuxi
Published: September 2018

Curing process-induced internal stress and deformation are major problems that restrict the wildly used of carbon fiber/epoxy composites in aerospace and vehicle industry. The finite element simulations of the evolution of cure-induced internal stress and curing deformation of the AS4/3601-6 composites are carried out using both elastic and viscoelastic models. The differences between these two kinds of numerical results are analyzed. The numerical results show that the difference between the two decreases with the increase of the fiber volume fraction or the decrease of the resin curing shrinkage. The comparative analysis is helpful for clearly understanding the deformation mechanism and then optimally designing the processing conditions in accordance with the specific needs.
Effect of Annealing Temperatures and Time on Structural Evolution and Dielectric Properties of PVDF Films
Authors: Zhu Yunfei , Ye Huijian , Yang Li , Jiang Lixiang , Zhen Liang , Huang Jianguo , Jiao Zilong , Sun Jipeng
Published: September 2018

In this paper, we investigate the effect of thermal annealing on the degree of crystallinity, the fraction of electro-active phase (β-phase) and the dielectric properties, such as dielectric constant and loss tangent. Through control the thermal annealing conditions, dramatic improvements have been achieved. The degree of crystallinity is greatly enhanced up to 45.2%. The relative content of electro-active phase increases remarkably by 61% and the dielectric constant is improved greatly by 17.8% and reaches its maximum value of 9.9 meanwhile the dielectric loss being as low as 0.026.
Structural Foamed Concrete with Lightweight Aggregate and Polypropylene Fiber: Product Design through Orthogonal Tests
Authors: Wu Yuexiu , Tan Xianjun , Liu Quansheng , Chen Weizhong , Meng Xiangjun , Deng Xiaolin , Li Weiqing
Published: September 2018

In order to optimize the mix ratio design for structural foamed concrete with lightweight aggregate (LWA) and polypropylene fiber, orthogonal test approach with an L32 (49) orthogonal array have been carried out, with nine factors (fly ash, perlite, foam, water, waterproof agent, antifreeze, polypropylene fiber, water reducing agent and accelerating agent) and four levels for each factor. Seven responses (quality of sample molding, distribution of fibers, dry density, water absorption, compression strength, tensile splitting strength and the ratio of tensile splitting strength to compression strength) of each formula have been measured. According to the analysis of test results, an optimal mix ratio of foamed concrete with the desired engineering properties is obtained.
Effects of CoCl2 and Other Additives on the Oxidative Chemical Synthesis and Properties of Poly(3-hexylthiophene)
Authors: Pratt C.M. , Foot P.J.S. , Davis R.
Published: September 2018

The chemical oxidative polymerisation of 3-hexylthiophene (3HT) by FeCl3 and the effects of reaction modifiers on the properties of the resulting polymer (P3HT) have been investigated. The process of polymerisation was identified using inhibitors that each affected one possible reaction mechanism. Gel permeation chromatography (GPC), UV-visible spectroscopy and proton nmr spectroscopy were employed to investigate the effects of the organic inhibitors and of added cobalt (II) chloride. Polymerisation appeared to proceed by two different mechanisms, one of which was strongly inhibited by cobalt chloride, whilst the other was favoured. CoCl2 was found to increase the molecular weight of the polymer substantially, and to make it more regioregular. As a result, the electronic conductivity of lightly iodine-doped P3HT was also enhanced.
Hardening Properties of Epoxy-Modified Cement Composites without Hardener
Authors: Jo Young Kug , do Jeongyun
Published: September 2018

Due to the major advantages of an epoxy-modified system suitable for constantly wet conditions, epoxy-modified cement composites are considered very competitive construction materials compared to latex-modified cement composites. Various performance factors of epoxy-modified cement composites, including strength, are strongly dependent on the hardening degree of epoxy resin, which affects the cost effectiveness of epoxy-modified cement composites. To meet the requirements and control the quality of epoxy-based construction products, the hardening degree of epoxy resin without hardener in cement composites needs to be analytically investigated. Thus, this study quantitatively characterized the hardening degree of epoxy resin with no hardener incorporated into the composites. In this study, the hardening degree and morphology of epoxy resin without hardener were characterized through various analytical approaches, including IR spectral analysis, gel permeation chromatography (GPC), thermo-gravimetric analysis-differential thermal analysis (TG-DTA), X-ray diffraction analysis of powder, and scanning electron microscopy (SEM). From the results of this study it was concluded that the hardening properties of epoxy resin in cement composites were efficiently characterized by the suggested analytical method, and the optimal polymer:cement ratio was found to be in the range from 10% to 20%.
Nanostructural Complex in ABS/TPU Immiscible Mixtures
Authors: Zitzumbo R. , Avalos F. , Alonso S.
Published: September 2018

The effects of modified organoclays on mechanical, rheological and mechanical-dynamical properties of acrylonitrile-butadiene-styrene/ thermoplastic polyurethane (ABS/TPU) were studied. ABS/TPU mixtures with 95/5, 75/25 and 50/50 wt.% were reinforced with 5 wt.% Cloisite 10A and 15A. The nanocomposites of the studied mixtures were prepared with an internal mixer at 210 °C following intercalation in the melting process. The intercalation/exfoliation of the silicate layers in the nanocomposites was confirmed by x-ray diffractometry (XRD). The results of thermomechanical-dynamical analysis demonstrated that ABS/TPU mixtures were incompatible. These results also revealed that organoclays have poor molecular interaction with TPU, in such a way that they are homogeneously dispersed in the styrene-acrylonitrile (SAN) of the ABS according to the polarity of the acrylonitrile. Through the viscoelastic analysis, it appeared that the organoclay particles embedded in the ABS/ TPU blend induced the formation of discontinuous nanostructured microdomains. These microdomains were formed by the intercalation/exfoliation of the organoclay particles with SAN, being surrounded by a TPU phase similarly to a core-shell configuration. Studies of the mechanical properties of the mixtures showed that low concentrations of TPU produced higher values of the respective Young's modulus, while higher concentrations of TPU led to practically no changes in the modulus either with or without the presence of organoclays. This was attributed to the molecular sliding of the nanostructured microdomains between the TPU polymeric chains.
Experimental Approaches to Investigation of the Interaction in between Anhydride Containing Copolymer and Poly (N-vinyl-Pyrrolidone) Blends
Authors: Can Hatice Kaplan , Kavlak Serap , Güner Ali
Published: September 2018

Blending or complexation of a polymer with another polymer has great practical interest, since this modification gives the chance to modify physical properties, functionality of polymer without synthetic reactions. In the present study, poly(maleic anhydride- alt-acrylic acid) [poly(MA- alt-AA)] was prepared by the binary copolymerization of the corresponding monomers by charge-transfer complex ( CTC) copolymerization. Water-soluble functional copolymers poly(MA- alt-AA) and poly( N-vinyl-2-pyrrolidone) (PVP) polymer blends were prepared by casting from water at room temperature, and their compatibility properties were investigated in the solid state. The high compatibility of poly(MA- alt-AA) and PVP can be explained by specific interactions between the carboxylic acid groups of the copolymer and the carbonyl groups of the PVP. Changes of the special features of the pure components and their various compositions in the blends were investigated by ATR-FTIR, HR-Raman and 1H-,13C-NMR spectroscopic techniques and dynamic mechanical analysis (DMA).
Preparation and Characterisation of Electrically Conductive Thermoplastic Vulcanisate Based on Natural Rubber and Polypropylene Blends with Polyaniline
Authors: Yong K.C.
Published: September 2018

Thermoplastic vulcanisates [TPVs] based on natural rubber, polypropylene and dodecylbenzenesulfonic acid-doped polyaniline [PAni.DBSA] with useful electrical conductivities (up to about 1.2 S cm−1) were produced by using an internal mixer. A very low electrical percolation threshold (about 2.0 wt.%/1.13 volume % of PAni.DBSA) was achieved for TPVs prepared via this method. All the TPVs exhibited useful physical properties and also a reasonable good electromagnetic interference shielding effectiveness [EMI SE]. The TPVs could be recycled up to 4 times without significant loss of their EMI SE, electrical and physical properties.
Thermal Conductivities of 2.5 Dimensional Woven Composites
Authors: Song Leilei , Geng Wei , Zhao Yufen , Chen Xiaoming , Li Jialu
Published: September 2018

The thermal conductivities of 2.5 dimensional (2.5D) woven composites were measured by using transient hot-wire method (THWM) in this study. The results showed that the THWM could also be used to measure the thermal conductivity of 2.5D woven composites, which were considered to be homogeneous materials. Heat diffusion models of the samples were simulated. The thermal conductivities of 2.5 dimensional woven composites increased with the warp fibre volume fraction when the hot wire was perpendicular to the warp direction. It was important that the thermal conductivity of 2.5 dimensional woven composites was found to be affected by the yarn size. Thermal conductivities also increased with the effective yarn size. Finally, thermal conductivities of 2.5 dimensional woven composites increased with the temperature from 288.15K to 298.15K, although the enhancement was not great. These conclusions indicated that the thermal conductivity of 2.5 dimensional woven composites was affected by the internal structure and the external environment.
A Study of the Friction Coefficients of Unidirectional and Woven Carbon Fibre/Epoxy Composites
Authors: Cheng B. , Kortschot M.
Published: September 2018

The friction coefficients of unidirectional carbon fibre/epoxy composites (with the fibres parallel and antiparallel to the sliding direction) were measured under severe abrasive conditions. Aluminium oxide sandpapers with three different grits (36, 80, and 120) were used as the counter surfaces. Three different applied loads (5, 10, 22N) and two different sliding speeds (2 m/s, 4 m/s) were selected as the testing parameters. Under these conditions, composites with fibres parallel to the sliding direction had a significantly lower friction coefficient. Using the measured friction coefficients of unidirectional composites, a modified rule of mixtures equation was developed to predict the friction coefficients of woven carbon fibre/epoxy composites under the conditions. The model is based on the hypothesis that the more wear resistant regions of the weave (fibres that are parallel to the sliding direction in this case) would protect the less wear resistant regions (fibres that are antiparallel to the sliding direction), and that the load is redistributed to yield equal wear rates for the two zones. It was found that the model was able to accurately predict the friction coefficients of the woven composites for the abrasive conditions tested in this study.
Recent Advanced Technologies in the Processing of Hybrid Reinforced Polymers for Applications of Membranes
Authors: Dixit Savita , Pal Sandhya
Published: September 2018

This review presents a comprehensive introduction to recent advances in the field of blends of the natural and synthetic polymers as new material for biodegradable membranes. These materials and several blends have attracted industrial attention because they exhibit improvements in properties which are required in membrane technology. In the current review, the structure, preparation coating method and properties of the blends of natural and man-made polymer are discussed. We focus on the applications of blend materials for membrane technology like fuel cells, membrane electrolytes and ultrafiltration membranes for water treatment. From the literature, it is found that the most common natural polymers: collagen, chitosan, chitin, cellulose, starch and poly(lactic acid) are used as components of blends with man-made polymers. We have also studied the introduction of nano-fibrous and nano-particles to improve the mechanical properties of these membranes.
Determination of Reactivity Ratios of Copolymerization of Acrylamide (Am) and Methacryloxyethyltrimethyl Ammonium Chloride (Dmc) with Ultraviolet Initiation, and Their Sequence Length Distribution
Authors: Wang Yonghong , Zhang Xinru , Li Wanjie , Cheng Jialiang , Liu Chengcen , Zheng Jiajun
Published: September 2018

The copolymer P(AM-DMC), one kind of cationic polyacrylamide, was synthesized by using acrylamide (AM) and methacryloxyethyltrimethyl ammonium chloride (DMC) as monomers with ultraviolet initiation. The copolymer was characterized by Fourier transform infrared spectroscopy. The composition of the copolymer was determined from the chlorine content by silver nitrate titration. The effects of monomer feed ratio and conversion on the composition of copolymer were discussed. Reactivity ratios were determined by the Fineman-Ross, Kelen-Tudos and Yezrielev-Brokhina-Roskin methods, indicating that their positive order calculation results were very different with those of reverse order, when the reactivity ratios were determined by Fineman-Ross. However, their positive order and reverse order calculation results were similar when the reactivity ratios were determined by the Kelen-Tudos and Yezrielev-Brokhina-Roskin methods. Therefore, the reactivity ratios were determined using the average results of the Kelen-Tudos and Yezrielev-Brokhina-Roskin methods. The reactivity ratios of AM and DMC were 2.3398 and 0.2285, respectively. This result showed that the copolymerization of AM and DMC was a non-ideal random copolymerization. Furthermore, the content of AM segments decreased with the increase of AM feed content, but the content of DMC segments increased. Moreover, the sequence length distribution was irregular and narrow, because AM was prone to homopolymerization.
Thermal and Mechanical Properties of Compression-Moulded Poly(Lactic Acid)/Gluten/Clays Bio(Nano)Composites
Authors: Mohamed Abdellatif A. , Finkenstadt Victoria L. , Gordon Sherald H. , Alamri Mohammed S. , Hussain Shahzad
Published: September 2018

Bio(nano)composites comprising agricultural-based polymers blended with biodegradable plant-based fillers and clays were produced to develop novel hydrophobic, yet biodegradable materials that have properties comparable to those of petroleum-based plastics. Poly(lactic acid) (PLA), vital wheat gluten (VG), and 3, 6, and 9% clays (NC1 or NC2) were mixed in a Haake Rheocord torque rheometer at 170 °C for 10 min. Blends were compression-moulded and tested using modulated DSC (MDSC), thermogravimetric analysis (TGA), Instron, FTIR and HPLC. The DSC profile of neat PLA exhibited a glass transition (Tg) and exothermic (Cry) followed by endothermic (Mel) transitions. The profile showed a Tg of 0.46 J/g/°C, Cry with 29.6 J/g, whereas Mel exhibited 28.3 J/g. Vital wheat gluten displayed a single Tg (0.45 J/g/°C). Enthalpic relaxation of PLA was noted in the presence of clays, where the overall DSC profiles of PLA were different, especially during melting. The hydrophobic nature of NC1 clay created shoulders during PLA melting. The degradation kinetics of the blends followed a multistep mechanism, as shown by the TGA data. The tensile strength dropped because of processing and due to the addition of clay, whereas elongation was reduced by the presence of NC1. Higher Young's modulus value due to NC1 or NC2 indicated stiffer bio(nano)composites. Better biodegradability was indicated after proteinase-K enzyme treatment in the presence of NC1. Due to the hydrophobic nature of NC1, the amount of the acetic acid-extractable protein was reduced. FTIR analysis showed no evidence of chemical reaction between PLA, gluten and the clays, but suggested the occurrence of significant non-covalent intermolecular interactions.
Experimental Verification of Lamb Wave Identification of Delamination Defects through Covariance of Energy Change
Authors: Yang Mijia , Bruhschwein Taylor
Published: September 2018

Delamination is currently a difficultly-detectable form of damage in composite laminate materials. This paper experimentally validates an innovative method that more easily detects delamination damage within composite materials through the covariance of energy change.

Lamb waves were introduced and recorded through an actuator and sensors made of piezoelectric material. The data was then analyzed through the Fast Fourier Transform (FFT). Using the data from FFT, the idea of covariance of energy change was suggested to correlate with defect characteristics. By comparing the covariance of energy change in beams with different delamination sizes and depths, correlations between the covariance of energy loss and defect characteristics were developed. With these correlations, the severity of these damages was quantified.
Evaluation of Mechanical Properties of Synthetic Fiber Reinforced Polymer Composites by Mixture Design Analysis
Authors: Manikandan A. , Rajkumar R.
Published: September 2018

The objective of this work is to investigate the mechanical properties of Glass fiber reinforced Epoxy composites with different weight proportions. Using hand lay-up technique followed by compression moulding, five composites were prepared by varying the Glass fiber from 15 wt.% to 35 wt.%. The necessary mechanical tests were conducted as per ASTM standards and surface morphology of the fractured surfaces was examined by Scanning Electron Microscope (SEM). As per the obtained results, it is concluded that the 25 wt.% fiber loaded composite has superior mechanical properties. The results are mathematically evaluated by adopting Mixture Design optimization technique. The predicted values establish that 25 wt.% fiber loading shows good mechanical properties compared to other combinations.
Experimental Study on Structural Characterization of Biocomposites
Authors: Murali K. , Vigneshwaran T. , Luke Justin Johnson G. , Karthikeyan G. , Suthan C.
Published: September 2018

There is an exceptional period of growth in the use of composites over the past decades in the aviation industry. Petroleum based synthetic composites have several properties that make them the choice for various applications. Also it posses good mechanical strength, chemical properties easy process ability, permanent stability, low price, and anti-bacterial properties. These composites are resistant to microbial attack and non degradable. The non-biodegradability of most commercially available plastics has caused many environmental problems associated with their disposal. A consequence of this phenomenal use of plastic materials is their increasing presence in municipal solid waste throw-away products. Increasing environmental concern forces for the use of newer type of materials which is more eco-friendly. Hence the bio-composite concept is developed. Bio composites are made from the natural fibers and are eco-friendly. Both the matrix phase and reinforcing phase are made by the natural fibers. Their properties can be improved by modifying their structure and by adding additives. This project aims in developing the new type of bio composite using Coir, Aloevera, Banana fiber, Baggase, Kenaf and then subjecting it to various tests to determine its properties and proving its promising usage in the aviation field.
Vibration Analysis of Nanoclay Filled Natural Fiber Composites
Authors: Arulmurugan S. , Venkateshwaran N.
Published: September 2018

In this work, the exfoliation of nanoclay in the polyester matrix was investigated using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) to evaluate the optimum parameters (frequency and time) in ultra-sonication technique. Various weight percent (1, 3, 5 and 7) of nanoclay is then mixed with polyester resin at optimum parameters. The mechanical properties and free vibration characteristics are investigated to determine the optimum clay percentage in the matrix. Further, with the optimum clay weight percentage, jute fibers of various weight percentages (5, 10, 15, 20, 25 and 30) were used to prepare the composite. The tensile, flexural, impact and free vibration characteristic of composite are found as per ASTM standards. From the results, it is found that 5% addition of nanoclay and 15% jute fiber increases the mechanical and vibration behaviour of the composites. Experimental modal analysis was carried out on a cantilever beam-like sample revealed that the addition of nanoclay and fiber has enhanced natural frequencies and damping ratio and the obtained natural frequencies are in good agreement with the theoretical results.
Fatigue Life Extension of Riveted Joints Using Fiber Metal Laminate Reinforcement
Authors: Kiran Babu K.M. , Sendhil Kumar S.
Published: September 2018

The components and parts made of sheet metals are commonly used in the automotive industry. Most of the sheet metal joints are bonded together using riveted joints. Stresses induced into these joints during usage may lead to assembly failure. In this paper, the mechanical and fatigue characterization of the riveted joints reinforced using fiber metal laminate (FML) is carried out. The tensile testing and fatigue testing of the specimens are carried out subsequently and the results illustrate that due to the presence of reinforcement between the riveted joints the overall mechanical strength and fatigue life of the riveted joints is improved by 19% and 21% respectively.
Free Vibration Analysis of Laminated Composite Plates Using Finite Element Method
Authors: Pingulkar Pushparaj , Suresha B.
Published: September 2018

In this work, the natural frequencies and mode shapes of a number of cantilever glass fiber reinforced polymer composites (GFRPCs) and carbon fiber reinforced polymer composites (CFRPCs) are numerically obtained using the commercial finite element analysis software (ANSYS). The laminates under study include 8 ply cantilevered plates having a plate aspect ratio of 2 and fiber volume fractions of 0.3, 0.4, 0.5, and 0.6. The finite element analysis procedure is described. The natural frequencies and mode shapes calculated using ANSYS are first validated with the results obtained from previous literature. The agreement between the two results is found to be excellent. The effect of change in the matrix material, hybridization, and laminate stacking sequence on the natural frequencies and mode shapes are also investigated. It is found that hybridization and orientation of the outermost layer has more significant influence on the natural frequencies of the laminated composite plates compared to fiber volume fraction and change in the matrix material.
The Effect of Higher Order Model on the Geometric Nonlinear Analysis of Antisymmetric Angle Ply Laminates
Authors: Swaminathan K. , Sangeetha D.M.
Published: September 2018

Geometric nonlinear analysis of simply supported antisymmetric angle-ply laminated composite plates are investigated based on first order and higher order displacement models with five degrees of freedom. Analytical formulations and solutions are developed based on Von-Karman nonlinear plate theory and Taylor's series expansion of displacement components. Equations of equilibrium are obtained using Principle of Minimum Potential Energy (PMPE) and closed form solutions using Navier's Solution technique. A four layered square plate is considered for the present study. Parametric studies are performed on both the models to study the behaviour of displacements and stresses in laminated composite plates. Comparative studies are performed on both the models and the effect of geometric nonlinearity is discussed.
Punching of Slag Based Concrete Incorporating Polymeric and Non-Polymeric Fibres
Authors: Vikram J. , Sekar K.
Published: September 2018

In recent years, many studies were made on the punching resistance of concrete slab incorporated with reinforcements. In a reinforced concrete slab, the ultimate strength is always governed by its punching shear capacity. Generally this shear capacity is increased by steel reinforcement. In addition to the steel reinforcement, incorporating fibres will enhance its shear capacity thereby increasing the ultimate strength. It is also been justified that application of fibre to increase punching shear capacity will be a viable solution. In this study, a conceptual mix of concrete was arrived based on three phase particle interaction. Based on the packing density evaluation 50% of cement is replaced with slag. This mix is incorporated with hybrid fibres such as polymeric fibres (polypropylene) and non-polymeric fibres (steel) in different aspect ratios. The test results shows that all the hybrid concrete mixes records a better result than the control concrete mix without fibre addition. The periphery and mid deflection is also measured and found to be relatively linear.
Modified Frosch Crack Width Model for Concrete Beams Prestressed with Cfrp Bars
Authors: Selvachandran P. , Anandakumar S. , Muthuramu K.L.
Published: September 2018

Fiber-reinforced polymer (FRP) composites are preferred as prestressing tendons in concrete structures due to its high-strength, lightweight and non-corrosive property. FRP based prestressed concrete member exhibits different crack behavior than steel based prestressed concrete member due to its less stiffness and non-ductile property. An experimental investigation was carried out to study the cracking behaviour of concrete member using Carbon fiber reinforced polymer (CFRP) bars as prestressing material. Experimental works includes four numbers of prestressed concrete specimens by varying degree of prestressing of 35 to 70%. The characteristics of crack spacing, crack propagation and crack widths of member were presented. Experimental results were compared with various researchers’ recommendation and proposed a new crack width model by modifying the Frosch crack width model.
Physical Properties of UV-cured Epoxy Nanocomposite Films
Authors: Lee Eun Ho , Kim Dae Su
Published: September 2018

Cationic UV-curing of a cycloaliphatic epoxy proceeds efficiently at room temperature, resulting in a highly crosslinked polymer network exhibiting the same excellent physical properties as obtained by thermal curing. However, the highly crosslinked rigid polymer network generally shows undesirable brittleness. Therefore, in this study, three kinds of reactive diluents, one epoxy and two polyols, were tested to prepare a cycloaliphatic epoxy film with reasonable physical properties by cationic UV-curing. Also, effects of nanosilica on the physical properties of the epoxy film were investigated. FTIR spectroscopy was used to investigate the UV-curing behaviour of the epoxy resin systems. Amongst the diluents enhanced UV-curing rate and final conversion levels, the epoxy diluent was the most effective. The tensile properties of the epoxy films were investigated by UTM. At a fixed diluent content of 30 phr, the film with the epoxy diluent showed best tensile strength. The film with the epoxy diluent 40 phr showed optimum tensile properties. The film with the epoxy diluent 40 phr showed further enhanced tensile properties at the nanosilica content 0.05 phr.
Bamboo Fibre-reinforced Self-compatibilizing Functionalized Polypropylene Composites by Palsule Process
Authors: Biswas Kishor , Palsule Sanjay
Published: September 2018

Bamboo fibre (BMBF) reinforced chemically functionalized polypropylene (CF-PP) composites (BMBF/CF-PP) with in-situ fibre/matrix interfacial adhesion have been processed by Palsule process without using any compatibilizer and without any fibre treatment by co-rotating twin screw extruder and injection moulding machine using raw, untreated bamboo fibres as reinforcement and chemically functionalized polypropylene (i.e., polypropylene grafted with 1.8% maleic anhydride) as the polymer matrix. Mechanical properties of the 10/90, 20/80 and 30/70 BMBF/CF-PP composites have been found to be higher than those of the CF-PP matrix and increase with increasing amounts of reinforcing BMBF in the composites. In-situ fibre/matrix interfacial adhesion resulting in the formation of BMBF/CFPP composites has been established by Field Emission Scanning Electron Micrograph (FE-SEM) and Fourier Transform Infra-Red (FTIR) spectroscopy.
Ionic Imprinting Polymers Using Diallylaminomethyl-Calix[4] Resorcinarene Host for the Recognition of Pb (II) Ions
Authors: Yusof Nor Nadiah Mohamad , Kobayashi Takaomi , Kikuchi Yasuaki
Published: September 2018

A novel ion-imprinted microspheres of copolymerized diallylaminomethyl-calix [4] resorcinarene and divinylbenzene were prepared through precipitation polymerization. These microspheres were used for the adsorption experiments of Pb (II) ions mixture solution containing Pb (II), Ni (II) and Cu (II). The selective complexion towards Pb (II) ions was examined. The adsorption was conducted in batches by investigating the effects of pH and initial concentration of a heavy metal solution. The adsorption of Pb (II) metal ions on the adsorbents had the optimum pH rating in region of 6. For single ion system, the imprinted polymer showed that the adsorption capacity of Pb (II) metal ions was 64 mg/g, while for Cu (II and Ni (II) were 24 mg/g and 8 mg/g, respectively. Competitive extraction experiments in the presence of Cu (II) and Ni (II) ions were also carried out and high selectivity of the imprinted polymer adsorbents towards Pb (II) over Cu (II) and Ni (II) was found. In ternary mixture of heavy metal ions, the imprinted polymer showed effective adsorption to Pb (II) obeying Langmuir isotherm. The outstanding adsorption abilities for Pb (II) metal ion have exhibited good prospects for disposal application of polluted water and environmental protection.
The Role of Phosphate Ester as a Fire Retardant in the Palm-Based Rigid Polyurethane Foam
Authors: Norzali Nor Rabbi'atul Adawiyah , Badri Khairiah Haji
Published: September 2018

Palm-based polyurethane containing phosphate ester (PE) as fire retardant has been developed. This study was conducted to investigate the effect of PE inclusion into palm-based polyurethane (PU) system onto the mechanical and burning property of the PU. The PE was synthesized via ring-opening hydrolysis between phosphoric acid (H3PO4) and epoxy. The synthesis was conducted at 60–70 °C with varying concentration of H3PO4 at 2.5, 5.0 and 7.5 wt.%. It was then added into the PU system at 0, 5, 10 and 15 wt.%. Density of the PU foam was in the range of 45–50 kg·m−3. PE increased the compression strength and modulus of the PU. The highest compression stress (1441 kPa) and modulus (7733 kPa) were discovered with the addition of 10 wt.% PE. Burning properties showed that the addition of PE has decreased the burning rate of the PU foam. PU with PE synthesized from 5.0 wt.% H3PO4 showed excellent burning properties with the lowest burning rate (0.047 cm·s−1) compared to control PU which was at 0.119 cm·s−1.
Preparation of Cellulose Nanocrystals Bio-Polymer from Agro-Industrial Wastes: Separation and Characterization
Authors: Mazlita Y. , Lee H.V. , Hamid S.B.A.
Published: September 2018

Lignocellulosic biomass from oil palm agro-industrial waste is highly potential to be valorised into cellulose polymer in nanoscale, which is useful for various applications. The present study discussed the synthesis of cellulose nanocrystal (CNC) from oil palm trunk (OPT) biomass via chemical-sonication process. The effect of pretreated alkali-bleached OPT and H2SO4 acid hydrolysed (40% and 60% w/w) cellulose were investigated by utilizing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Biomass crystallinity, thermal stability and chemical functional group suggested that the pretreatment process has successfully isolated cellulose from OPT, which indicated the removal of lignin, hemicellulose and impurities from the palm fibers. Furthermore, SEM and TEM images revealed that CNC40 and CNC60 were observed in rod-shaped structure with the dimension of 100.00 nm (L) x 27.50 nm (d) and 95.00nm (L) x 25.00nm (d), respectively, and corresponded to the aspect ratio of 3.63 and 3.80, respectively. In the presence of sonication condition, the study suggested that both 40 and 60%w/w of H2SO4 rendered active effect for acid depolymerisation of cellulose at 45 °C and 15 min of time. Thus, this can concluded that milder acid (40%w/w) was able to produce cellulose in nanosizes under mild operating condition with the assistant of sonication effect.
Biodegradability and Thermal Properties of Hybrid Montmorillonite/Microcrystalline Cellulose Filled Polylactic Acid Composites: Effect of Filler Ratio
Authors: Arjmandi Reza , Hassan Azman , Haafiz M.K. Mohamad , Zakaria Zainoha
Published: September 2018

The objective of this study is to investigate the effects of partial replacement of montmorillonite (MMT) with microcrystalline cellulose (MCC) on the biodegradability and thermal properties of hybrid MMT/MCC filled polylactic acid (PLA) composites prepared using solution casting technique. Based on our previous study, the optimum MMT content based on having the highest tensile strength in PLA/MMT nanocomposites is 5 phr (parts per hundred parts of polymer). Therefore, the PLA/MMT/MCC hybrid composites were prepared at a total filler content of 5 phr. The biodegradability and thermal properties of PLA hybrid composites were investigated using soil burial test and thermogravimetric analysis, respectively. The biodegradability of PLA/MMT/MCC hybrid composites (1 phr MMT and 4 phr MCC) at 8th week significantly increased by approximately 228% and 367% compared to the optimum formulation of PLA/MMT nanocomposite and neat PLA, respectively. In addition, Fourier transform infrared spectroscopy (FTIR) revealed the formation of hydrogen bonding between the fillers and PLA matrix. The thermal stability of hybrid composites improved from 358.3 to 362.2 °C by incorporation of hybrid MMT/MCC (1 phr MMT and 4 phr MCC) into PLA matrix, as demonstrated by maximum decomposition temperature.
Properties of Epoxidized Natural Rubber Tread Compound: The Hybrid Reinforcing Effect of Silica and Silane System
Authors: Sarkawi Siti Salina , Aziz Ahmad Kifli Che , Rahim Rohaidah Abdul , Ghani Rassimi Abdul , Kamaruddin Ahmad Nazir
Published: September 2018

Modification of natural rubber via epoxidation process increases its compatibility with highly polar filler like silica. In this work, epoxidized natural rubber (ENR) reinforced with silica compound is evaluated for truck tire tread compound. The rheological, physical and dynamic properties as well as the bound rubber content of ENR-silica tread compound are discussed. The results show that ENR-silica compound has high chemically bound rubber indicating the good interaction and bonding between rubber and silica. In addition, the dynamic test shows the ENR-silica vulcanizate exhibit higher Tan delta at 0 °C and lower tan delta at 60 °C as compared to conventional natural rubber-carbon black vulcanizate, which gives indication of higher wet grip and lower rolling resistance of the ENR vulcanizate. The use of ENR reinforced with silica filler in tread compound is a unique combination that offers renewable material for greener tire application.