bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Ammonium Polyphosphate Modified with 3-(Methylacryloxyl) Propyltrimethoxy Silane on the Flammability and Thermal Degradation of Pine-Needles
Authors: Li Liping , Hu Hongdan , Hu Haiqing
Published: September 2018

This paper investigated the influence of ammonium polyphosphate (APP) and ammonium polyphosphate modified with 3-(methylacryloxyl) propyltrimethoxy silane (M-APP) on flame retardancy and thermal degradation of pine needles. The presence of M-APP increased the char residue and decreased the pyrolysis temperature of pine needles observed by TGA. The addition of M-APP shifted the degradation peaks of pine needles to lower temperatures observed by DTG. The cone calorimetry test results showed that the situation of HRR, THR, SPR, TSP and the mass loss (%) on pine needles treated with M-APP was sharply less than the other samples. On the other hand, M-APP prolonged the ignition time (TTI) compared with the other samples. Therefore, M-APP has an overall better performance than APP on pine needles.
Preparation and Properties of Core-Shell Particles Filled β-Nucleated Polypropylene Random Copolymer Composites
Authors: Li Youchen , Zhang Guixin , Fu Xiaowei , Guo Weihong
Published: September 2018

To provide polypropylene random copolymer (PPR) with excellent toughness without lowering its rigidity, a novel kind of core-shell particles (CSP) and β nucleating agent (β-NA) were incorporated into PPR by melt blending. The CSP, in which nano-CaCO3 acted as the core and polyethylene (PE) formed the shell, was also prepared through melt blending. The effects of different proportion of PE shell and nano-CaCO3 core on the properties of β-modified PPR composites were investigated. The dispersion and morphology of CSP were studied by transmission electron microscopy (TEM) and the results showed that the CSP dispersed fairly well in the PPR matrix and the core-shell structure was successfully formed. The nano-CaCO3 core was completely encapsulated by PE, especially at the 50/50 weight ratio. The crystallization behaviour of the PPR composites was characterized by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and polarized optical microscopy (POM). All the results showed that the relative content of β-form crystal was greatly enhanced with the incorporation of β-NA. Furthermore, the weight ratio change of PE/nano-CaCO3 could also increase the relative content of the β-form crystal. Under the combined effects of β-modification and CSP, the mechanical properties of the PPR composites were greatly enhanced without reducing its rigidity.
Temperature Distribution and Curing Behaviour of Carbon Fibre/ Epoxy Composite during Vacuum Assisted Resin Infusion Moulding Using Rapid Heating Methods
Authors: Gu Yizhuo , Qin Xing , Li Min , Zhang Kaomin , Zhang Zuoguang
Published: September 2018

This paper designs two kinds of rapid heating methods for vacuum assisted resin infusion moulding (VARIM) process aiming to reduce the cycle time of carbon fibre/rapid curing epoxy composite fabrication. One utilizes the silicone rubber heating sheet containing thin resistance wires, and the other takes advantage of carbon fibre conductivity to produce internal resistive heating. Conventional oven heating VARIM was performed as a reference. The heating rates and temperature distributions in carbon fibre preform heated by the three heating methods with and without epoxy resin injection were investigated and compared. The curing degree and glass transition temperature of laminates fabricated by different VARIM processes were determined. The heating rate of silicone rubber heating sheet was 26 °C/min, while the carbon fibre internal resistive heating reached 30 °C/ min, which was much higher than the heating rate of 2 °C/min in oven. Unlike the highly uniform temperature distribution in the oven heating process, there was a slight temperature gradient within 5 °C in the silicone rubber heating process and a relatively large gradient within 13 °C in internal resistive heating process for dry fibre preform. When epoxy resin was injected, the temperature gradients obviously increased along the resin flowing direction especially for the rapid heating methods. However, the temperature gradient seemed not to affect the curing degree and its uniformity of laminates for all studied VARIM processes. The cycle time of composite fabrication by the rapid heating VARIM processes was reduced by over 40% compared to oven heating VARIM.
Investigation on Mechanical Properties of Occ Fiber-Hdpe Composite Containing Different Types of Coupling Agents
Authors: Damabi R. Mohebi , Rashno A. , Ahmadi S.
Published: September 2018

In this study, the effects of adding different coupling agents, e.g. maleic anhydride-grafted polyethylene (MAPE), silane (3-aminopropyltrimethoxy silane) (silane 1189) and isocyanate (hexamethylenediisocyanate) (HDI) on mechanical and morphological properties of composite samples of high density polyethylene/old corrugated container fibres (HDPE/OCC) were studied. The amounts of OCC fibre and coupling agents used were 30% and 2% of dry composite weight, respectively. Mixing of materials was carried out by a two-screw counter extruder and samples were prepared by injection moulding. In order to compare the results of the use of mixture coupling agents, their effects were studied independently, as well. Mechanical properties of prepared composite samples containing coupling agents were measured and the results were compared with those of pure high density polyethylene and those of composite samples without coupling agent. The measured mechanical properties showed that maximum values of tensile and flexural strengths and tensile and flexural modulus could only be obtained in composites containing a mixture of silane1189 and MAPE coupling agents. It was also observed that the Izod impact strength values of composites with coupling agents increased significantly.

SEM micrographs of failure surfaces of samples showed that the best homogeneity of composites and bonding between OCC fibres and polymer matrix were obtained for the sample containing 1 wt.% silane and 1 wt.% MAPE.
The Tribological and Mechanical Properties of Pdcpd/Pew Composites Prepared by Reaction Injection Moulding
Authors: Wang Liping , Pan Bingli , Du Jinping , Cheng Yumei , Liu Jichun , Du Sanming , Shangguan Bao , Zhang Yongzhen
Published: September 2018

In order to improve mechanical performance and wear resistance of polydicyclopentadiene (PDCPD) by convenient methods and technologies, novel PDCPD/polyethylene wax (PEW) composites were prepared by in-situ polymerization in a simulated reaction injection moulding. Studies on the mechanical and tribological properties of the composites were carried out. The bending strength and hardness of PDCPD/PEW composites significantly improved compared with neat PDCPD. The incorporation of PEW in PDCPD greatly enhanced the wear resistance and reduced the friction coefficients. The wear mass loss and friction coefficients for PDCPD/ PEW composites decreased continuously in the range of our experiments. The SEM micrographs of the worn surface showed the friction and wear mechanism of PDCPD.
Effect of Maleic Anhydride-Grafted Polypropylene Content on the Bond Properties of Crimped Macro Polypropylene Fibre in Styrene Butadiene Latex-Modified Cement-Based Composites
Authors: Oh Ri-On , Lee Seung-Kee , Park Chan-Gi
Published: September 2018

The influence of maleic anhydride-grafted polypropylene (mPP) on the bond characteristics of macro propylene (PP) fibre and styrene butadiene (SB) latex-modified, cement-based composites was investigated. The mPP content ranged from 0 to 40% of the cement weight. Bonding strength and interfacial toughness were measured in accordance with standard method JCI SF-8. Both bonding strength and interfacial toughness increased with increasing amounts of mPP up to 15% but decreased with mPP levels above 20%. mPP strengthens the interfacial bonding between fibre and cement by forming hydrogen bonds. Because mPP is hydrophilic, it also fills pores created at the interface between macro PP, a non-hydrophilic material, and the cement composite. As a result, the overall bonding performance of the composite was enhanced by increasing the frictional force and inhibiting crack generation and growth under fibre pullout loads. These mechanisms were confirmed by fine structure analyses of the micro-PP fibre surface after pullout tests. The amount of mPP used in the composite had a strong influence on the frictional force generated at the interface between the fibre and the cement matrix.
The Filling of a Mould Cavity with Simultaneous Impregnation of the Reinforcing Porous Layer
Authors: Baranov A.V.
Published: September 2018

The isothermal filling of a flat mould cavity by a Newtonian fluid with simultaneous impregnation of the reinforcing porous layer is investigated. The flow in the cavity is described by inertialess Navier-Stokes equations, the flow in the porous layer by Darcy's law, and the flow in the region adjacent to the ‘liquid–porous layer’ boundary by the Brinkman equation.
Statistically Designed High and Low Methyl Acrylate (Ma) Containing Ema-Ethylene-Octene Copolymer Double Network Hybrids: Interesting Contrast in Physico-Mechanical, Rheological and Electrical Properties
Authors: Pervin Rumiya , Mondal Soumya , Goswami Luna , Vijayabaskar V. , Bandyopadhyay Abhijit
Published: September 2018

This paper demonstrates interesting contrasts between physical, mechanical and rheological properties of double network hybrids developed from high (30 wt.%) and low (9 wt.%) methyl acrylate containing poly (ethylene-co-methyl acrylate) and poly (ethylene-co-octene) thermoplastic elastomer. The compositions were designed adopting a Taguchi L9 statistical model. The model was espoused to consider a wide range of blend compositions and process conditions for optimization. The majority of the low methyl acrylate containing hybrids showed normal correlation between mechanical and other physical properties with the net gel content while for the other variety, they were ambiguous. The reason was investigated and it was found to be due to the influence of the nature of crosslinks formed between the phases which controlled the properties in the latter. Based on the results, finally, two blend compositions were chosen from each set as the most optimized formulations for future study.
Wavelength Sensitivity in Polypropylene/Clay Composite Photo-Oxidation
Authors: Aslanzadeh Samira , Kish Mohammad Haghighat
Published: September 2018

The photo-oxidation behaviour of polypropylene/maleic anhydride-grafted polypropylene/organic modified montmorillonite (PP/PPgMA/OMMT) composites with short wavelength (UVC) and long wavelength (UVA) ultraviolet radiation was examined. The samples were prepared in a co-rotating twin-screw extruder and compatibilizers with different degrees of maleation were used. The photo-oxidative stability was studied using FTIR spectroscopy and microscopy. During UVA exposure, the rate of photo-oxidation of PP/PPgMA/OMMT increased with the amount of maleic anhydride from 0.1 to 0.5 wt.% in PPgMA. However, even after 2500 h of exposure to the radiation, the FTIR spectrum of pristine PP did not show significant changes. For UVC radiation, the rate of photo-oxidation of PP/PPgMA/OMMT composites was the same as that of pristine PP. On the other hand, there was a difference between PP and PP/PPgMA/OMMT composites in the formation of a crack on the back surfaces of the sheets facing the UVC sources. The difference was due to the presence of Fe3+ in clay layers that had the effect of UV-protection and blocking in the UVC region.
Phase Morphology and Mechanical Properties of Aliphatic Waterborne Polyurethane-Ureas: Effect of 1,6-Hexamethylene Diisocyanate (Hdi)/Isophorone Diisocyanate (Ipdi) Ratio
Authors: Fu Heqing , Liu Kang , Yan Caibin , chen Weifeng , Wang Yin
Published: September 2018

Aliphatic waterborne polyurethane-ureas (WPUU) were prepared using 1,6-hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI) as mixed diisocyanates. The effects of the HDI/IPDI ratio on the phase morphology of WPUU films including the hydrogen bonding, crystallization of the soft segment and hard segment, and phase separation were investigated. The relationship between the phase morphology and the mechanical properties was also studied. The FTIR spectrum showed that the hydrogen bonding degree in the hard segments increased as the HDI/IPDI ratio increased. XRD analysis revealed the excellent crystallinity of WPUU films. DSC analysis indicated that the degree of phase separation was improved with increasing HDI/IPDI ratio, and DMA analysis showed that the storage modulus of the WPUU film increased at first and then decreased. When the HDI/IPDI ratio was 4:1, the WPUU films exhibited high tensile strength.
Factors Affecting on the Electricity Properties of a Metal/Pet Composite during Tensile Deformation
Authors: Chen Mei-yu , Lai Kan , Sun Run-jun , Fang Hong-tian , Liu Wei
Published: September 2018

The effects of different factors on the electrical properties of a well-bonded metal/PET composite during tensile deformation were systematically analyzed, including metal materials, metal coating film thickness and environmental temperature. It was found that, before a crack appearance in the coated metal film, the critical elongation of a well-bonded metal/PET composite depended on the differences of modulus and Poisson's ratio between the coated metal material and PET substrate. After cracking, the metal/PET composites with different metal films showed different elongations when there was a sudden increase in the resistance of the metal/PET composite; the thicker the metal film deposited on PET substrate was, the lower resistance the metal/PET composite had. The thickness of metal film had no obvious effect on the critical elongation of the metal/PET composites. In addition, the resistance of the metal/PET composite increased with the increasing environmental temperature.
The Properties and a New Preparation of Ethylene Propylene Diene Monomer/Montmorillonite Nanocomposites
Authors: Yang Ming-Chien , Kao Bo-Jyue , Tsou Chi-Hui , Suen Maw-Cherng , Wu Chin-San , Tsou Chih-Yuan , Chu Chih-Kuei , Yao Wei-Hua , Wu Wen-Yan , Hong Wei-Sung , Lee Kueir-Rarn
Published: September 2018

In this study, ethylene propylene diene monomer (EPDM)/organic clay nanocomposites were prepared using melt intercalation to explore how the nanoclay affected their structures and mechanical and thermal properties. Montmorillonite (MMT) modified with hydrochloric acid (HCl) and maleic anhydride (MAH) was employed to improve the compatibility of the EPDM and MMT phases. The effects of the modified clay on the properties of the EPDM were compared with those of commercially available MMTs (Clay10A and Clay30B) synthesized using an alternative modifier. The nanoclay structures of the EPDM/clay nanocomposites were characterized using X-ray diffraction (XRD), and their thermal and mechanical properties were examined a using thermogravimetric analysis (TGA) and universal tensile testing machine.

MMT spacing can be increased with the addition of hydrochloric acid and maleic anhydride (MAH). The XRD results showed no diffraction peak for the EPDM and modified MMT (ClayMAH) composites, verifying that the MMT was exfoliated. The TGA results showed that the thermal decomposition temperature and the residual can be enhanced by increasing the ClayMAH content, the pyrolysis temperatures of EPDM/ClayMAH, EPDM/Clay10A, and EPDM/Clay30B are similar because of the barrier effect phenomenon. The mechanical properties can also be improved with additional ClayMAH content because the clay is dispersed in EPDM. A decline in the crosslinking density increases the slidability between polymers, which enhances the mechanical properties of the nanocomposite. ClayMAH is more effective for improving the tensile property compared to Clay10A and Clay30B.
Preparation, Characterization and Anti-Bacterial Activity of Zinc Oxide-Gelatin Nanocomposite Film for Food Packaging Applications
Authors: Umamaheswari G. , Sanuja S. , John Vino Arul , Kanth Swarna V. , Umapathy M.J.
Published: September 2018

Gelatin based composite films were prepared using various crosslinking agents for possible application in the food packaging industry. In the present study, gelatin films were formed by the incorporation of zinc oxide (ZnO) nanoparticles. The ZnO nanoparticles were synthesized by a wet chemical method using zinc nitrate as precursor and starch as stabilizing agent. It was characterized by FTIR. Surface morphology and thermal studies were performed by SEM and TGA respectively. The average particle size was calculated from the X-ray diffraction pattern using Scherrer's equation. Mechanical studies were done with a Universal Testing Machine. The distribution of particles was clearly seen by SEM and thermal studies showed that the decomposition temperature of gelatin was increases by the incorporation nano ZnO. The mechanical properties were also improved with increase in concentration of nano ZnO. Antibacterial activities of the films were also studied against S. aureus, V. cholera and E. coli by the disc diffusion method.
Porosity Effect on Residual Flexural Strength following Low Energy Impact of Carbon Fibre Composites
Authors: Arthurs B. , Bull D.J. , Arumugam V. , Chambers A.R. , Santulli C.
Published: September 2018

Studies of the combined effects of the presence of porosity (as it may result from partially effective cure cycles) and of low-energy impact damage on the residual properties of CFRP laminates have led so far to controversial results. In particular, it is not clear from the literature whether the presence of voids would blunt crack propagation following impact or rather would promote damage development. These effects would respectively either increase or reduce post-impact residual strength, relative to that of the laminate with virtually no voids, as the result of an optimal manufacturing procedure. With this in mind, different cure cycles have been applied to produce carbon fibre-reinforced polymer (CFRP) composites with various levels of void content, which were subjected to low energy impact damage (3, 4.5 and 6 J) and then to post-impact flexural strength measurement. Damage assessment using micro-focus computed tomography (μCT) was used to complement traditional ultrasonic C-scans, which proved ineffective on the high-porosity samples. Three cure-cycles were investigated: one which led to high porosity (average void content 4 vol%) and two conventional low-porosity cure cycles, only one of which included a post-cure cycle. This study has found that, despite a lower initial flexural strength, higher residual flexural strength was retained after impact in the high-porosity material than in the low-porosity one. This is explained by the lower extent of impact damage observed in the high porosity material, where voids had the effect of suppressing delamination propagation.
Reinforcement Role of Carbon Nanotubes: Interfacial Properties of Carbon Fibre - Epoxy Nanocomposite
Authors: Ya Min , Pyrz Ryszard
Published: September 2018

Single-walled carbon nanotube (SWCNT) reinforced epoxy was fabricated as the matrix material for carbon fibre reinforced composite. SWCNT-epoxy sample with a single fibre on the top of the surface was loaded incrementally to sufficient strain levels to cause interfacial failure. Fibre strain profiles were obtained at each level of the applied strain by Raman spectroscopy. The strain distributions obtained agree well with the Cox shear-lag model and Piggott partial-debonding model that are conventionally used to describe load transfer at interface. No full-debonding phenomenon was observed. Interfacial shear stress (ISS) distribution was derived at each applied matrix strain. Interfacial shear strength (IFSS) increases after introducing SWCNT in the epoxy resin, which can be explained by the increase of shear yield stress of the matrix material and the increase of radial pressure at the interface resulting from thermal residual stress. The residual strains in the matrix in the vicinity of the single carbon fibre were also mapped by using of the Raman spectra of SWCNT. Stress concentration zones were observed around the fibre ends.
Dispersibility of Hydrophilic and Hydrophobic Nano-Silica Particles in Polyethylene Terephthalate Films: Evaluation of Morphology and Thermal Properties
Authors: Gashti Mazeyar Parvinzadeh , Moradian Siamak , Rashidi Abosaeed , Yazdanshenas Mohamad-Esmail
Published: September 2018

The development of polyethylene terephthalate (PET) nanocomposites with different nano-fillers has been an especially intense area of research due to an enhancement in thermal and physical properties of nanocomposites compared to pure PET. In this regard, the surface properties of nano-particles and their interactions with PET chains have a critical role on different properties of prepared nanocomposites. The aim of this paper is to study the influence of the type of nano-silica particles with different surface properties on the dispersibility, the interfacial adhesion, surface morphology, nucleation and thermal properties of the resultant PET/silica nanocomposites. For this purpose, PET composites containing hydrophilic or hydrophobic nano-silica were prepared by melt compounding. Different properties of nanocomposites were investigated using polarized optical microscopy (POM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), dynamical mechanical thermal analysis (DMTA) and contact angle measurements (CAM). POM images indicated that nano-silica tended to increase the number of spherulites in the PET composite structure depending on the type of particles. The thermal studies of the nanocomposites showed a slight decrease in the melting temperature compared to the pure PET.
Pullout Performance of Common Construction Fasteners from Long Fiber Thermoplastic Composites
Authors: Kaliberov Danila , Vaidya Uday
Published: September 2018

The recent increase in cyclone activity in the last 20 years has pressured the construction industry to look for alternative materials for roof construction. Although plywood is a cheap material, its mechanical properties are highly dependent on moisture content. Long fiber thermoplastics are an emerging type of plastic materials that feature enhanced mechanical properties due to high aspect ratio discontinuous fibers in a tough polymer matrix. The present study focuses on comparing the pullout strength of commonplace fasteners from plywood and long fiber thermoplastic composite panels. Specimens were tested according to ASTM standards D1761-88 and D6117-97 for mechanical fasteners in wood and long fiber thermoplastic (LFT) composites. Common construction nails like 6D, 10D and 16D and a #8 screw were used to compare the performance in terms of withdrawal. The data showed that LFT composites had withdrawal strength on average two to three times that of plywood for all tested fasteners types. Experimental data was analytically verified by APA TT-109 guidelines.
Qualifying Dispersion and Distribution of Carbon Nanotubes in Polyamide Matrix during Melt-Mixing by Flow Simulation
Authors: Loux C. , Prashantha K. , Roger F. , Lacrampe M.F. , Krawczak P.
Published: September 2018

This work aims at numerically simulating the flow of nanocomposites in a twin-screw mixer so as to develop a prediction tool of nanofiller dispersion and distribution in a polymer matrix during processing. The rheological behaviour of polyamide 6 / carbon nanotubes blends (PA6/MWCNT) containing from 1 to 5 wt.% of MWCNT was investigated over a large range of shear rates (0.1 to 100 s−1) and temperatures (230 to 245 °C). The macroscopic dispersion of the nanotubes was assessed by dynamic rheometry. Viscosity laws of the nanocomposites were characterized and implemented in a finite element software package to compute the velocity, pressure and temperature fields during the mixing process. A good agreement was founded between the calculated and measured torques. The dispersive and distributive capability of the flow was numerically evaluated and compared to the nanotubes dispersion quality experimentally qualified by oscillatory rheometry. Experimental and numerical results are complementary and allow better understanding the mixing capability of the twin-screw mixer used to compound nanocomposites.
Toughening Polystyrene by Core-Shell Rubber Particles: Analysis of the Internal Structure and Properties
Authors: Zhou Chao , Wu Shuting , Yang Bowen , Gao Yunxia , Wu Guangfeng , Zhang Huixuan
Published: September 2018

A series of polybutadiene-graft-polystyrene (PB-g-PS) core-shell structural rubber particles has been prepared by grafting styrene onto polybutadiene seeds via emulsion polymerization. All the PB-g-PS particles were designed with the same chemical composition and similar grafting degree but different internal structures. The difference in internal structure was realized by controlling the allocation of ‘external grafting’ and ‘internal grafting’ of styrene. Three different internal structures: rare sub-inclusion, small size sub-inclusions and large-scale sub-inclusions in the rubber phase were observed by transmission electron microscopy. Slight aggregation of rubber particles of PB-g-PS with large-scale sub-inclusions was found in PS/ PB-g-PS blends. The results of dynamic mechanical analysis showed the PB-g-PS with small size sub-inclusions had lower glass transition temperature than the others. Izod test results showed that the PB-g-PS with large-scale sub-inclusions could toughen the PS matrix more effectively. The deformation mechanisms responsible for these effects are discussed.
Chitosan/Cellulose/Halloysite Membranes Produced Using Solvent Casting Method
Authors: Govindasamy Kavitha , Ramli Muhammad Hafiz , Pasbakhsh Pooria , Pushpamalar Vengidesh , Salamatinia Babak
Published: September 2018

Polymer biocomposites have attracted a lot of attention due to the increasing requirements for biomaterials to replace conventional materials. This replacement is due to the remarkable properties of biomaterials, including their biocompatibility, biodegradability and non-toxicity. Chitosan (CS) is a renowned abundantly-available biopolymer that is furnished with such properties. However chitosan is known to be unstable in acidic conditions, and it has fairly low mechanical strength and requires further improvement for various applications. This study aims to improve the properties of chitosan by making composites of CS reinforced with carboxymethyl cellulose (CMC), microcrystalline cellulose (MCC) and halloysite nanotubes (HNTs). These composites were prepared through solvent casting method and were investigated for their mechanical, chemical and morphological properties. The mechanical testing results showed that the CS/MCC membranes had the best mechanical properties, with a tensile strength (σ) of 79.98±8.12 MPa and a Young's modulus (E) of 2.44±0.21 GPa. Scanning electron micrographs confirmed that the high mechanical strength of CS/MCC membranes is attributed to better dispersion of MCC in chitosan. Infrared spectroscopy compared the chemical interactions between the main functional groups of the matrix and fillers. A surface wettability test was performed and revealed that chitosan membranes reinforced with 10 (w/w%) of CMC had the lowest (88.45°) and chitosan membrane with 5 (w/w%) HNT and 5 (w/w%) had the highest contact angle (130.83°). Addition of both CMC and MCC led to an improvement of the mechanical properties over the pure chitosan membrane, which was attributed to a significant interaction between chitosan and cellulose through hydrogen bonding.
Manufacturing and Performance Evaluation of Polyurethane Composites Using One-Part and Two-Part Resin Systems
Authors: Mohamed M. , Hawkins S. , Chandrashekhara K.
Published: September 2018

Polyurethane (PU)-based composites show superior performance compared to polyester and vinylester composites. The demand for PU composites is increasing in high technology as well as conventional applications such as infrastructure and automobile. In this study, glass fiber reinforced composite laminates using one-part and two-part PU resin are manufactured using vacuum-assisted resin transfer molding (VARTM) process. A new generation two-part thermoset PU resin system is investigated and compared with commercial one-part PU resin systems. The mechanical performance of glass fiber reinforced composites manufactured using two different PU resin systems is evaluated. Tensile and flexure tests are conducted on both neat resin and glass/PU composites. Low-velocity impact tests are performed on both types of glass fiber reinforced PU composite specimens. Mechanical properties including strength and modulus were measured and analyzed for the two resin systems. Differential scanning calorimetry (DSC) is used to study the cure behavior of both resin systems. A Brookfield LVDV-II programmable rotational type viscometer is employed to study the viscosity profiles of the resin systems. The influence of resin properties on the overall performance of glass fiber reinforced composites is discussed.
Fracture Behaviour of Epoxy Resins Modified with Liquid Rubber and Crosslinked Rubber Particles under Mode I Loading
Authors: Imanaka Makoto , Ikeda Keisuke , Nakamura Yoshinobu , Kimoto Masaki
Published: September 2018

Three-point bending tests were conducted with two kinds of rubber-modified epoxy resins: a liquid rubber-modified epoxy resin and a nano-elastomer particle-modified one. In most studies on rubber-toughened epoxy resins, fracture toughness has been evaluated by critical stress intensity factor or critical energy release rate, where the crack is assumed to propagate rapidly, and stable crack propagation has not been considered. However, stable crack propagation was observed for the present rubber-modified epoxy resins. To take into account crack propagation, fracture toughness was characterized using the crack-growth resistance curves (R-curve). In the present study, the evolution behaviour of the damage zone near the crack tip was observed using a video-microscope for the two kinds of rubber-modified resins. Furthermore, to investigate microscopic fracture mechanisms, the fracture surfaces were observed by scanning electron microscopy, and side views near the crack tip were also observed by a confocal laser scanning microscopy.
Direct Synthesis of P3Ht/Cds Nanocomposites with End-Functionalized P3Ht as the Template
Authors: Ma Haihong , Gao Hong , Zhou Zhengfa , Xu Weibing , Ren Fengmei
Published: September 2018

In this article, we report a direct synthetic route to prepare P3HT/CdS nanocomposites with cadmium acetate dihydrate (Cd(OOCCH3)2.2H2O) used as the cadmium source, sulfur powder (S) as the sulfur source, dichlorobenzene (DCB) and dimethyl sulfoxide (DMSO) as cosolvents, phosphonic ester end-functionalized P3HT as a conjugated polymer template. The as-prepared P3HT/CdS nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy, X-ray diffraction (XRD) patterns, transmission electron microscope (TEM), ultraviolet-visible (UV-vis) and photoluminescence (PL) spectra. The results showed that the size and distribution of CdS nanocrystals were not only temperature-dependent, but also greatly influenced by the S/Cd molar ratio. CdS nanocrystals were dispersed uniformly in the P3HT/CdS nanocomposites, which indicated that end-functionalized P3HT could be used as a template to prevent CdS from aggregating effectively. The occurrence of charge transfer at the P3HT/ CdS interface was evident from UV-vis absorption and PL studies, which indicated that ionic bonding between CdS nanocrystals and phosphonic ester end-functionalized P3HT can promote the transfer of charge in P3HT/ CdS nanocomposites. Therefore, it is a promising method to simplify the procedure for large-scale synthesis of organic-inorganic nanocomposites used in solar cells with high photoelectric conversion efficiency.
Effect of Clay Types on the Properties of Silane Compatibilzied Metallocene Polyethylene/Clay Nanocomposites
Authors: Chen W.-C. , Lai S.-M. , Yang Chen-Hau , Tang Shi-Xian , Liao Zong-Ching
Published: September 2018

The interaction between the intercalant within clay and the compatibilizer is essential to the properties of nanocomposites, and the compatibilizer properties are often neglected. In this work, we have deliberately used a low crystallinity polyolefin elastomer as a compatibilizer to investigate if the inferior mechanical properties of the compatibilizer compared with those of the matrix would counteract the effects of high dispersion of clay in the mPE/clay systems. Melt-mixed mPE (metallocene polyethylene)/clay nanocomposites were thus prepared using a low-crystallinity polyolefin elastomer (mPE-g-silane) as a compatibilizer under two different types of commercial clay (Cloisite 20A and 30B) with different organic affinities to mPE-g-silane, to investigate both intercalant and compatibilizer effects. According to X-ray diffraction and transmission electron microscopy analyses, all 20A-filled nanocomposites showed fairly well-dispersed clay within the mPE matrix in comparison with 30B-filled cases due to a larger d-spacing of 20A for easier access of the compatibilizer, even though a higher affinity between 30B and the compatibilizer was expected. Measurable gel content was observed for 20A-filled systems, but not for 30B-filled systems. Tensile properties and tear strength of 20A-filled samples were higher than those of 30B-filled samples, again due to the high dispersion effect in 20A-filled samples. Thus, the affinity of 20A clay with silane agent was quite essential for these compatibilized mPE/clay systems, despite of the weak mechanical properties of the compatibilizer. Clearly, a subtle balance of the interfacial interaction, interface properties and clay dispersion is essential to attain the good mechanical properties of mPE/clay nanocomposites.
Production and Characterization of Flame Retardant All-Polyamide Composites by a Film-Stacking Method
Authors: Seyhoglu Hatice , Doğan Mehmet
Published: September 2018

The aim of this study was to produce flame retardant all-polyamide (PA) composites with acceptable tensile properties. Firstly, the effect of consolidation temperature on tensile properties of composites was investigated to find the optimum processing temperature. Flame retardant composites were produced at the optimum consolidation temperature (240°C). Aluminium diethyl phosphinate (AlPi) and its mixture with melamine polyphosphate and zinc borate were used for producing flame retardant all-PA composites. The flammability properties of the composites were investigated by limiting oxygen index (LOI) and UL-94 standards. According to the flammability test results, AlPi was more effective than its mixture and 10 wt.% AlPi containing composite showed V0 rating with a LOI value of 27.6. As well as the flammability properties, the addition of both types of flame retardant additives increased the tensile strength and Young's modulus values with respect to the pristine all-PA composite.
Non-Isothermal Crystallization Behaviour and Kinetics of LLDPE/REDMUD Blends
Authors: He Chaofeng , Cao Xinxin , Huo Guoyang , Luo Sihai , He Xiaofang
Published: September 2018

The non-isothermal crystallization behaviour of pure LLDPE and LLDPE/REDMUD blends was investigated by differential scanning calorimetry (DSC), and the crystallization kinetics was analyzed by three methods, namely the Jeziorny, the Mo and the Ozawa. The results show that an optimal content of REDMUD (lower than10 wt.%) can enhance the kinetic crystallizability of the system because of heterogeneous nucleation, but excessive REDMUD, by physical hindrance, would impair the kinetic crystallizability. In non-isothermal crystallization kinetics, the Ozawa model did not fit well with the crystallization behaviour of these systems, while the Jeziorny and Mo models were found to be applicable. Furthermore, the activation energy ΔE calculated by the Kissinger method for the transport of macromolecular segments to the growing surface of crystal nucleus indicates that REDMUD could significantly reduce the crystallization migration activation energy of these blends.
Deconsolidation and Its Interdependent Mechanisms of Fibre Reinforced Polypropylene
Authors: Brzeski Markus , Mitschang Peter
Published: September 2018

Thermoplastic composites offer the possibility of post processing by re-melting of the polymer, but this can lead to a loss of consolidation. The aim of this study is to investigate and quantify the mechanisms leading to deconsolidation. A model is introduced based on the first law of thermodynamics including the following mechanisms: decompaction of the fibre reinforcement network affected by the stored energy during compaction, void evolution due to the surface tension and the gas expansion, moisture in the polymer, and external pressure. These deconsolidation mechanisms are interdependent and have a significant effect on deconsolidation. The modeling approach predicts the deconsolidated state with good agreement to physical measurements.
High Performance Phenolic Resin Based on Untreated Natural Herbaceous Lignin
Authors: Kimura Hajime , Ohtsuka Keiko , Matsumoto Akihiro , Ougi Takeshi , Ishibashi Yoshiaki , Yamano Kohji
Published: September 2018

In this study, the aim was to prepare a high performance phenolic resin based on natural lignin and to reveal its characteristics. Generally, even though natural lignin is simply added to phenolic resins, and since the reactivity of lignin with the thermal fluidity is low, modification of phenolic resin by such lignin does not proceed sufficiently. Therefore, natural herbaceous lignin which is reactive with phenolic resins was used as the natural lignin, and the preparation and properties of the phenolic resin based on herbaceous lignin were investigated. The properties of the phenolic resin modified with herbaceous lignin were determined and compared to the same phenolic resin with normal woody lignin and without any lignin. It was found that the phenolic resin modified with herbaceous lignin showed good heat resistance, mechanical properties, dimensional stability and electrical insulation properties compared with those of the phenolic resin with the woody lignin and without lignin.
Optimizing the Performance of Natural Fiber Reinforced Plastics Composites: Influence of Combined Optimization Paths on Microstructure and Mechanical Properties
Authors: Toupe Jean Luc , Chimeni Désiré Yomeni , Trokourey Albert , Rodrigue Denis
Published: September 2018

This study investigated the combination of two different optimization paths (phase compatibilization and manufacturing process optimization) on the microstructure (fiber dimensions, matrix crystallinity and matrix molecular properties) and mechanical properties (flexural and tensile moduli, impact strength, and tensile stress at yield) of flax fiber/postconsumer recycled plastic composites. A two-step optimization methodology was adopted. First, the material composition was optimized by phase compatibilization using maleic anhydride grafted polypropylene (MAPP) and maleic anhydride grafted ethylene octene metallocene copolymer (EO-g-MAH) as additives. Then, the manufacturing process (extrusion followed by injection) was optimized in terms of temperature profile and screw speed for extrusion, as well as barrel temperature profile, mold temperature, injection speed, injection pressure, injection time and back pressure for injection. The results showed that, besides good fiber-matrix interfacial adhesion, the combination of both optimization paths promoted an optimum balance between components degradation and composite homogeneity (good fiber and additives dispersion in the matrix), leading to better mechanical properties. It is shown that this optimization procedure was able to improve all the mechanical properties of the composites, as well as being effective in terms of performance and costs.
Study on Thermal Stability and Non-Isothermal Crystallization Behaviour of Polyethylene/Clay Nanocomposites
Authors: He Fu-An , Zhang Li-Ming
Published: September 2018

In this work, thermal stability and non-isothermal crystallization behaviour of polyethylene/clay nanocomposites prepared by in-situ polymerization were studied. The thermal degradation kinetics of polyethylene/clay nanocomposites in nitrogen was investigated by a pseudo-first order method indicating that the addition of clay filler in polyethylene matrix could improve the thermal stability of nanocomposites. The Ozawa, Avrami, and modified Avrami-Ozawa methods were applied to study the non-isothermal crystallization behaviour of polyethylene/clay nanocomposite. It was found that the clay filler not only acted as a heterogeneous nucleation for the crystallization of polyethylene but also hindered the transport of the polyethylene molecule chains at the same time, resulting in a decrease of the crystallization growth rate of polyethylene with clay loading. In addition, the nucleation activity and the activation energy for the crystallization of polyethylene/clay nanocomposites were also estimated.
Fatigue, Resilience, Hardness, and Swelling Behaviour of Natural Rubber/Recycled Acrylonitrile-Butadiene Rubber (Nr/Nbrr) Blends
Authors: Ismail Hanafi , Ahmad Hazwani Syaza , Rashid Azura A.
Published: September 2018

In the present study, the fatigue, resilience, hardness, and swelling behaviour of natural rubber and recycled acrylonitrile-butadiene rubber (NR/NBRr) blends were studied in the concentration range from 5 to 35 phr of recycled NBR. NBR gloves have excellent resistance to punctures, tear and many types of chemicals, while NR has good physical and mechanical properties. Blending NBRr into the rubber blends improved the processability, stiffness and resilience and conferred excellent oil resistance. The fatigue life of NR/NBRr blends decreased as the NBRr content increased, due to the incompatibility and poor dispersion of NBRr in the NR matrix. However, increasing NBRr content gave NR/NBRr blends better resistance towards swelling and hardness. Both properties increased due to the improvement in crosslink density when more NBRr was added, but the resilience properties exhibited an opposite trend. Scanning electron microscopy study indicated that the recycled NBR shows a coarser and poor dispersion in NR matrix particularly when more NBRr content was used, which leads to lower fatigue life of the NR/NBRr blends.
Design of a Flat Plate Specimen Suitable for Biaxial Tensile Tests on Polymer Materials
Authors: Chowdhury Nayeem Tawqir , Wang John , Chiu Wing Kong
Published: September 2018

Since the introduction of fibre-reinforced polymer composites there has been a surge in the use of adhesives for joints and repairs, and polymer resins as the matrix material for fibre-reinforced composites. The failure mechanisms of these materials have been studied by many researchers; however, there is little accurate experimental data under tension-tension loading published. This is due to the lack of a standard specimen design to perform these tests. The authors propose a flat plate specimen design that has been shown to overcome some of the difficulties presented in literature. A series of tests with this specimen configuration were conducted under varying biaxial loading conditions. The results are plotted in the tension-tension quadrant of the materials failure envelope. For the two polymer materials tested; a linear truncation within the first quadrant of the failure envelope was found.
Fabrication and Application of Low-Pressure Wax Injection Rapid Toolings
Authors: Kuo Chil-Chyuan , Tsai Ren-Lung
Published: September 2018

This paper proposes a method to produce silicone rubber moulds for low-pressure wax injection moulding. Wax spilling is one of the most troublesome problems during the wax injection moulding process. From the point of view of green manufacturing, the optimal processing conditions in the wax injection moulding process were investigated using the Taguchi method. The experimental results revealed that the most influential factor affecting the weight of spilled wax is the injection time. The optimal processing conditions in the wax injection moulding process are an injection temperature of 82 °C, an injection time of 2 s, an injection pressure of 0.6 kgf/ cm2 and a mould temperature of 60 °C.
Utilization of Chicken Eggshell Waste as a Bio-Filler for Thermoplastic Polymers: Thermal and Mechanical Characterization of Polypropylene Filled with Naturally Derived CaCo3
Authors: Hassen Ahmed Arabi , Dizbay-Onat Melike , Bansal Dhruv , Bayush Theresa , Vaidya Uday
Published: September 2018

The processing and characterization of polypropylene/eggshell composites was the main objective of this study. Natural source-derived calcium carbonate (CaCO3) was extracted from waste chicken eggshell and compounded with polypropylene polymer. The compound was molded using the Extrusion Compression Molding (ECM) process. X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analysis were conducted on the eggshell to characterize its constituents. The effects of filler loading, 30 wt.% eggshell and 30 wt.% eggshell with 5 wt.% of maleic anhydride grafted polypropylene (MAPP) on the mechanical and thermal properties were studied. The addition of a small amount of MAPP during melt extrusion improved the dispersion and bonding of CaCO3 particles in polypropylene. 7.49% decrease in tensile strength, 35.51% enhancement in flexural modulus and 66.05% increase in notched Izod impact energy were obtained by adding 30 wt.% eggshell with 5 wt.% MAPP to polypropylene. Adding 30-wt % of eggshell filler and 5 wt.% MAPP to polypropylene delayed the flame propagation time by 99 seconds.
A Comparison of Mape and Peg Effects on the Mechanical Characteristics of Wheat Straw/Ldpe Biocomposites for Packaging Application
Authors: Tajeddin Behjat
Published: September 2018

A viable solution for replacing petroleum-based materials is to combine petroleum and bioresources materials to produce biocomposites having the requisite properties for packaging applications. Although biocomposites have many applications in different purposes such as building construction and aircraft industries, their applications in the packaging engineering are still novel. Therefore, in this study, a biocomposite consisting of low-density polyethylene (LDPE), wheat straw (WS) and the compatibilizers Maleic Anhydride Polyethylene (MAPE) and Polyethylene Glycol (PEG) with molecular weights of 400 and 600, was produced based on the requirements of the packaging industry. By performing different mechanical tests such as tensile, flexure and impact, the effects of the compatibilizing agents was determined. The ratios of the matrix to the filling phase applied to the compound were 70/30, 60/40, 50/50, and 40/60, and the compatibilizers were used at the levels of 0, 7, and 10% respectively. The MAPE compatibilizer improved the tensile properties. The compatibilizer type had no effect on the impact strength properties of the biocomposites. The flexural strength of all compounds was higher than that of the control.