bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of the Compatibiliser on the Morphology and Properties of Dynamically Cured PP/EPDM/Epoxy Blends
Authors: Jiang Xueliang
Published: September 2018

Dynamic vulcanisation was successfully applied to epoxy resin reinforced polypropylene (PP)/ethylene-propylene diene elastomer (EPDM) blends, and the effects of different compatibilisers on the morphology and properties of dynamically cured PP/EPDM/epoxy blends were studied. The results show that dynamically cured PP/EPDM/epoxy blends compatibilised with maleic anhydride-grafted polypropylene (MAH-g-PP) have a three-phase structure consisting of EPDM and epoxy particles dispersed in the PP continuous phase, and these blends had improved tensile strength and flexural modulus. While using maleic anhydride-grafted EPDM (MAH-g-EPDM) as a compatibiliser, the structure of the core-shell complex phase and the PP continuous phase showed that epoxy particles could be embedded in MAH-g-EPDM in the blends, and gave rise to an increase in impact strength, while retaining a certain strength and modulus. DSC analysis showed that the epoxy particles in the blends compatibilised with MAH-g-PP were more efficient nucleating agents for PP than they were in the blends compatibilised with MAH-g-EPDM.
Phase Transition and Degradation Characteristics of Poly(urethane-Siloxane) Copolymers
Authors: Yeh Jen-Taut , Shu Yao-Chi
Published: September 2018

Poly(urethane-siloxane) (PU-Si) copolymers consisting of soft and hard phases presented a two-phase structure when analysed by differential scanning calorimetry. The copolymers showed a narrow glass transition region of soft segment between −116 °C and −119 °C and a narrow breadth of this transition within 3 °C. Both results indicated that the copolymers had a high degree of phase separation. The stress-strain curves showed that the copolymer with high phase separation exhibited low tensile strength.

The hard phase presented several endothermic regions above room temperature. The first and second endothermic regions, which can be regarded as a short-range ordering and a long-range ordering respectively, appeared at about 60~120 °C and 160~200 °C. An endothermic peak appeared at around 200 °C which was attributable to a crystalline region.

Two-stage degradation of copolymers was clearly observable in thermogravimetric analysis (TGA). Although the degradation of the copolymers was similar to that of typical polyurethane (PU), the shoulder of the derivative thermogram (DTG) curve was different. To examine this unique shoulder, the copolymers were examined using a slower heating rate. There were four stages of degradation, which was again different from the behaviour of PU. Degradation of the hard phase occurred between 200~400 °C in two stages, resulting from two distinct hard-segment types.

Degradation of the soft phase occurred between 400~600 °C and there were also two stages related to the decomposition of PDMS soft segments and macroclics.
Cylindrical Orthotropic Thermal Conductivity of Spiral Woven Composites. Part III: An Estimation of their Thermal Properties
Authors: Chiu Chang-Hsuan , Hwan Chung-Li , Cheng Chao-Chuan , Tsai K. -H.
Published: September 2018

This is the third in a series of papers on the cylindrical orthotropic thermal properties of spiral woven composites. Based on the mathematical model by the authors, a parameter estimation technique has been used to evaluate the effective thermal properties by verifying the predictability of the mathematical model. Good agreement was found between the temperatures measured in a transient heat conduction experiment and those calculated using the prediction equations formulated by the estimated parameters.
Effects of Winding Angles on the Strength of Filament Wound Composite Tubes Subjected to Different Loading Modes
Authors: Hamed A.F. , Khalid Y.A. , Sapuan S.M. , Hamdan M.M. , Younis T.S. , Sahari B.B.
Published: September 2018

Filament wound pipes constructed from a corrosion resistant epoxy resin and E-glass filament fiber wound at nine different wind angles were tested. Experimental data are presented to show the effects of winding angle on the strength of 46.05 mm diameter tube and 300 mm length under three different loading modes. The pipes were tested to failure under hoop pressure loading (mode I) biaxial pressure loading (mode II), and biaxial pressure with axial compressive loading (mode III). Stress/strain response up to fracture for three different winding angles under different loading modes were obtained. The test results show the effect of the winding angle on elastic constants and on non linear stress strain behaviour. The test results also show that the optimum winding angles for filament wounded pipes depend on the loading modes applied. It shows that for loading mode I the filament wound pipe should be wound at 55°, for loading mode II the filament wound pipe should be wound at 75°, while for loading mode III the filament wound pipe should be wound at 85°.
Effect of Anhydrides on the Mechanical, Thermal and Morphological Properties of TPS/PE Blends Made by One-Step Extrusion
Authors: Jing-lin Yu , Ji-ping Pang , Shu-jun Wang , Jiu-gao Yu
Published: September 2018

Thermoplastic starch/polyethylene blends containing maleic anhydride (MAH), succinic anhydride (SA) and phthalic anhydride (PA) were prepared by one-step extrusion, in a single-screw extruder, in the presence of dicumyl peroxide. The morphological, mechanical and thermal properties of the blends were characterised by scanning electron microscopy (SEM) and thermogravimetric analysis and also by measuring elongation at break (%) and tensile strength (MPa). Blends made with MAH had better properties than those with SA and PA. The SEM showed that they also had better interfacial adhesion. Because of the existence of carbon-carbon double bonds in MAH, it could graft to the polyethylene chains and act as a compatibiliser during the extrusion process.
Effect of Propylene Carbonate on Physical Properties of Wood Fibreboard Composite
Authors: Ghosh Arun , Sain Mohini
Published: September 2018

The effect of propylene carbonate as an accelerator on the mechanical performance and dimensional stability of composites made from wood fibre bonded with wood resin and urea formaldehyde resin was investigated. The results demonstrated that the mechanical performance of the composite fibreboard cured at a relatively low temperature (e.g., 180 °C) could be markedly enhanced by addition of propylene carbonate. Composites cured at higher temperatures (e.g., 200 °C or 220 °C) and/or in presence of propylene carbonate, exceeded the minimum physical properties specified by ANSI-AHA. The addition of 3% propylene carbonate (by weight, based on total fibre and resin content) could optimise the physical properties of the composites. The tensile stress parallel-to-the-surface and the flexural strength and stiffness of the composites increased in presence of propylene carbonate.
Composites of Acrylonitrile-Butadiene-Styrene Filled with Wood-Flour
Authors: Matuana L.M. , Cam S. , Yuhasz K.B. , Armstrong Q.J.
Published: September 2018

This study examined both the use of acrylonitrile-butadiene-styrene (ABS) as a plastic matrix for wood-plastic composites (WPCs) and the effect of impact modification on the mechanical properties of ABS/wood-flour composites. Blends of ABS filled with wood flour (both pine and maple) were processed into profile shape using a conical twin-screw extruder and the mechanical properties of the resulting composites were characterised and compared to WPCs made with polyolefins (HDPE and PP) and rigid PVC matrices. Generally, WPCs made with ABS matrix outperformed their polyolefin counterparts in both flexural strength and modulus, whereas ABS-based composites had inferior strength but greater modulus than those made with rigid PVC. The impact strength of ABS/wood-flour composites was below that of wood plastic composites made with polyolefins. However, impact modification with acrylonitrile-butadiene-styrene terpolymers had some effect in toughening of the ABS/wood-flour composites.
High Strength Polymer-Modified Repair Cementitious Composite for Fire Protection
Authors: Won Jong-Pil , Choi Seok-Won , Park Chan-Gi , Jang Chang-Il
Published: September 2018

The purpose of this study was to evaluate the mechanical performance and fire resistance of a high strength polymer-modified cementitious composite, to test its ability to repair concrete tunnel structures that are in danger of collapse due to cracks or deterioration. In particular, because existing repair materials are not fire-resistant and commercial fire-resistant materials have low strength, this study was aimed at increasing the water tightness and strength of a repair material and also making it resistant to fire. In addition, this study evaluated changes in internal temperature depending on the cover thickness of repair materials to determine the optimal cover thickness at which a high strength polymer-modified cementitious composite could protect existing concrete tunnel structures from fire. Results indicated that the high strength polymer-modified cementitious composite had superior strength and water tightness than commercial fire-resistant materials and it also provided good fire resistance. The high strength polymer-modified cementitious composite required to be applied in an optimal layer thickness of at least 40 mm to protect existing structures from fire.
A Study of the Mechanics of Porous Plga 85/15 Scaffold in Compression
Authors: Leung Linus , Perron Josee , Naguib Hani E.
Published: September 2018

Constitutive modelling of the stress-strain relationship of open-celled PLGA 85/15 bioscaffolds under compression was studied. A constitutive model for compressive behaviour was directly derived from the morphology of a unit cubic cell. These constitutive equations describe the stress-strain relationship as a function of the foam's material properties and cell morphology, such as elastic modulus, yield stress, relative density, cell strut thickness, and cell size. To verify this model, uniaxial compression testing was performed on scaffold samples. Using the gas foaming/salt leaching method, the samples were prepared by using different foaming parameters such as salt/ polymer mass ratio, saturation pressure, and saturation time. The comparisons of theoretical and experimental data demonstrate that the constitutive model using a cubic unit cell accurately describes the behaviour of PLGA foams with low relative densities under compression.
Synthesis and Properties of Poly(Methylphenylsiloxane) Containing Methacryloyl Groups
Authors: Sun J.T. , Huang Y..D.
Published: September 2018

Methacryloxypropyltrimethoxysilane (MPTS) was used as the modified monomer to synthesise polymethylphenylsiloxane containing methacryloyl groups (PMPS-M) through co-hydrolysis and polycondensation with other silane monomers. The effects of MPTS on the synthesis and on the thermal and adhesive properties of PMPS-M were investigated by using Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential thermogravimetry (DTG), scanning electron microscopy (SEM), and measurements of adhesion using a shear test. The results indicated that PMPS-M with good storage stability was synthesised successfully when the amount of MPTS was less than 8 wt%.

PMPS-M had higher thermal stability than PMPS. The onset degradation temperature for PMPS-M containing 8 wt% MPTS was 518 °C, while it was 463 °C for PMPS. The improvement in thermal stability may be due to the protective effect of the methacryloyl groups, as observed under SEM. The shear strength of PMPS-M was 4.2 MPa when containing about 8 wt% MPTS, about 50% higher than that of PMPS. The shear strength of PMPS-M was also higher than that of PMPS at high temperatures.
Incremental Damage Development in a 3D Woven Carbon Fibre Composite
Authors: King S. , Stewart G. , McIlhagger A.T. , Quinn J.P.
Published: September 2018

Interest in 3D woven carbon fibre composites has increased within industries such as aerospace, automotive and marine, due to their high strength to weight ratio, their increased tailorability and their capacity to be manufactured into near net shape preforms, thereby reducing parts count, assembly time, labour intensity and costs. It is vital that critical areas of concern such as damage (and in particular damage initiation and development) are studied and understood, thereby reducing the limiting factors to their acceptance.

The damage initiation and subsequent intervals of development for ILSS (Interlaminar Shear Strength) were determined experimentally. Particular focus is paid to the significance of binder edge and binder middle testing and the influence of through-the-thickness (T-T-T) reinforcement in relation to damage types and development. Control samples for binder edge and binder middle loading locations were tested to failure as a means of determining an average point of failure, allowing the generation of testing intervals.

The performance and architecture of samples from each incremental interval were characterised using a combination of graphical analysis and optical microscopy with the aid of dye-penetrant to highlight fibre damage and matrix cracking. Samples displayed specific damage initiation points, thus allowing the generation of a damage guide relating to applied force.

In addition, the results imply that a relationship exists between the location of applied load and subsequent damage, thus showing the significant influence played by the T-T-T binder loading location on damage development within 3D woven carbon fibre composites.

Some of the preliminary data shown in this paper was presented at IMC23 at the University of Ulster, UK in August 2006 and at Texcomp 8 in Nottingham, UK October 2006.
An Investigation into the Effect of Compaction on the Mechanical Performance of a 3D Reinforced Advanced Composite
Authors: Stewart G. , McIlhagger A.T. , Quinn J.P. , King S.
Published: September 2018

Industries such as aerospace, marine, automotive and construction are now embracing advanced composites processed using resin infusion techniques. These composites consist of complex fibrous reinforcements and polymeric matrices. They can offer lower costs and equivalent or greater performance than can composites produced via more expensive traditional techniques such as autoclaving. As a result they are gaining increasing acceptance. One such material is a 3D fibre reinforced composite which possesses superior strength and stiffness in the through-the-thickness (T-T-T) direction compared to 2D composites due to their T-T-T binder tows. However, due to the T-T-T binder it is harder to achieve the required high fibre volume fraction (Vf) for optimum performance. This paper investigates a 3D fibre reinforced composite and how its structure and mechanical properties are affected by increasing Vf.

Some preliminary results in this paper were presented as a conference paper at IMC23 in August 2006.
Detection and Estimation of Monomeric Eluates from Poly(Methyl Methacrylate) Resin of Various Polymerisation Modes
Authors: Amin Wala M.
Published: September 2018

High-performance liquid chromatography coupled to an ultra-violet detector method was used to monitor the elution profile of methyl methacrylate monomer from poly (methyl methacrylate) resin produced by various polymerization modes. Three types of polymer were investigated, one auto-polymerised, one heat-polymerised, and a microwave-polymerised resin type. The study was conducted on five discs from each type in both distilled water and artificial saliva.

The results showed that the three resins demonstrated a rapid dumping of their residual methacrylic acid whereas their un-polymerised methyl methacrylate monomer continued to leach out to both artificial saliva and distilled water throughout the five-week test period. It was shown that the three resins differed significantly (p< 0.05) in the elution profile of their methyl methacrylate, with the microwave-polymerised type showing the highest amount of leached out monomer whereas the heat-polymerised type showed the lowest amount of monomer diffusion. The results also showed that the amount of eluates leached out from the investigated polymers into the artificial saliva was larger than into water.

The findings of this study warned that the risk of a chemical trauma to the oral soft tissues is significant and imminent immediately after delivery of a newly constructed prosthesis. Such a trauma, however, could be substantially minimised by immersing the oral appliances in water for one week before insertion.
Preparation and Stability of Copper Particles Formed Using Amino-Terminated Dendrimer as Template
Authors: Wei Xiuzhen , Zhu Baoku , Xu Youyi
Published: September 2018

Amine-terminated seventh generation dendrimers (G7-NH2) were synthesised and employed to investigate the interior and exterior template processes for the preparation of copper particles. Ultra-violet spectroscopy and transmission electron microscopy were used to characterise the absorption properties of the G7-NH2(Cu2+)n complexes and the morphology of G7-NH2(Cu)n composite particles, respectively. Unlike the case where dendrimers with hydroxyl end-groups are used, copper particles could be prepared by exterior template process. Both the size of the copper particles and their tendency to aggregation increased as the Cu2+/G7-NH2 molar ratio increased. The copper particles were stable under oxygen-free conditions and could easily be oxidised to G7-NH2(Cu2+)n complex ions in the presence of oxygen.
Morphology and Rheological Properties of Polyethylene/Polystyrene Blends
Authors: Kossentini-Kallel Tasnim , Massardier-Nageotte Valérie , Jaziri Mohamed , Gerard Jean-François , Elleuch Boubaker
Published: September 2018

The objective of the present work was to study the evolution of the morphology and rheological properties of PE/PS blends with different compositions.

Blends ranging from pure A to pure B component were prepared using a single-screw extruder to simulate a convenient industrial process. The analyses of the blend morphologies highlighted the poor adhesion between the two phases and revealed a direct dependence on their composition.

The observed variations in the rheological properties and morphology seem to be in agreement with the composition of the blends.
Mechanical and Thermal Properties of Poly(Lactic Acid)/Starch/Montmorillonite Biodegradable Blends
Authors: Ren Jie , Liu Zichao , Ren Tianbin
Published: September 2018

Poly(lactic acid) (PLA)/starch/montmorillonite (MMT) biodegradable blends were prepared in a twin-screw extruder. The effect of MMT content on the mechanical and thermal properties of the blends was studied. The microstructure of the composites was observed by wide-angle X-ray diffraction and transmission electron microscopy, and the results showed that there was a stacked and intercalated-and-flocculated structure in the blends. The blends of PLA/starch with MMT had a lower crystallisation temperature (Tc) than without MMT. This means that MMT made the crystallisation of PLA easier. The melting temperature of PLA (Tm) was not significantly affected by the addition of MMT. These blends had a high tensile strength of approximately 40 MPa and a high flexural strength of approximately 80 MPa. The maximum tensile and flexural strengths were obtained when the MMT content was 2 wt.%. The water absorption of the blends with MMT was lower than without it.
Mechanical Characterisation of Polyurethane/Clay Nanocomposites
Authors: Rihayat T. , Saari M. , Mahmood M. Hilmi , Yunus W.M.Z. Wan , Suraya A.R. , Dahlan K.Z.H.M. , Sapuan S.M.
Published: September 2018

Polyurethane/clay nanocomposites have been synthesised from renewable sources. A polyether polyol was obtained by a method involving the synthesis of palm oil-based oleic acid from glycerol. This was then used in the production of a polyurethane by reaction with an isocyanate. Dodecylbenzene sulfonic acid (DBSA) was used as catalyst and emulsifier. The unmodified clay (kunipia-F) was treated with cetyltrimethyl ammonium bromide (to form “CTAB-mont”) and octadodecylamine (to form “ODA-mont”). The d-spacing in CTAB-mont and ODA-mont were 1.571 nm and 1.798 nm respectively, i.e. larger than that of the original “pure-mont” (1.142 nm). The organoclay was intercalated in the polyurethane, as confirmed by a wide angle x-ray diffraction (WAXD) pattern. The mechanical properties (including the dynamic mechanical properties) of pure polyurethane (PU) and PU/clay nanocomposites were measured. The results indicate that 1–5 wt.% of organoclay gave the most significant improvements in tensile properties and in glass transition temperature.
The Effect of Metal Chelates of Poly(Iminoethylene) Dithiocarbamate Copolymer Interchelated with Montmorillonite on the Fire Retardancy of Polypropylene
Authors: Nour Mohamed A. , Gilman Jeffrey W.
Published: September 2018

The flammability properties of polypropylene (PP) were improved using metal chelates of poly(iminoethylene) dithiocarbamate copolymer intercalated with montmorillonite. These chelates were obtained from prepared intercalated Zn, Cu, Ni and Co metal chelates of poly(iminoethylene) dithiocarbamate copolymer with montmorillonite. Cone calorimetry was used to assess the flammability of the formulated PP samples. The thermal stability of the materials produced was studied using thermogravimetric analysis (TGA) and good thermal stability with high char yield was observed.
Effect of Graphite Powder on Sliding Performance of Sintered Polyimide Composites at Various Normal Loads and Sliding Velocities
Authors: Samyn P. , Quintelier J. , Schoukens G.
Published: September 2018

Polymer composites with graphite additives are often used to control sliding properties. The lubricating action of graphite, however, strongly depends on the working conditions of normal load and sliding velocity. Sintered polyimide with 15 wt.-% graphite powders is worn under 50 to 200 N normal loads and 0.3 to 1.2 m/s sliding velocities in line contact with a steel counterface. The tribological properties of graphite are unfavourable under low sliding velocity and high normal loads, causing high friction and wear rates. The transfer film then mainly consists of rough graphite flakes, and large wear debris particles indicate overload, as the loading capacity of graphite is limited. Graphite powders reduce coefficients of friction from 0.45 to 0.12 under medium to high sliding velocities and normal loads. The transfer films are rendered smooth by mixing polyimide and graphite fillers. Stabilisation in friction and wear as a function of normal load and sliding velocity (pv-value) coincides with levelling of the maximum polymer surface temperature of 115 °C. The favourable action for graphite under sliding, i.e. mechanical shear, and the improved thermal conductivity of the polymer bulk, control the sliding mechanisms of polymer composites under certain sliding conditions.
Phase Behaviour and Thermal Stability of Imide-Containing Siloxane-Urethane Copolymers
Authors: Liao S.K. , Jang S.C. , Lin M.F.
Published: September 2018

Imide-containing siloxane-urethane copolymers (I-PU copolymers) were synthesized from 4,4'-diphenylmethane diisocyanate (MDI), OH-terminated polydimethylsiloxane (PDMS) and pyromellitic dianhydride (PMDA). The hard segment consisted of urethane and imide segments and the soft segment was PDMS. The DSC of I-PU copolymers suggests that they had a high degree of phase separation in their low hard segment contents and phase mixing in high hard segment contents. DMA indicates similar phase behaviour and shows that incorporating imide segments into the copolymers can maintain the high modulus at high temperature. The progress of degradation of I-PU copolymers was determined by TGA and standard kinetics methods and there were three stages at around 250~425 °C, 425~560 °C and 560~700 °C, respectively. The first stage was dominated by the hard-segment structure and content. Incorporating imide segments into PU raises the characteristic temperatures of degradation in the first stage. The second stage resulted from the degradation of the PDMS soft segment to form oligomers by the interchange reaction. The degradation of the imide segment leads to the third stages because the maximum rate of degradation in DTG curves increases with the imide content.
Morphological Characterisation of Bacterial Cellulose-Starch Nanocomposites
Authors: Grande Cristian J. , Torres Fernando G. , Gomez Clara M. , Troncoso Omar P. , Canet-Ferrer Josep , Martinez-Pastor Juan
Published: September 2018

Acetobacter sp. growing medium was modified in order to produce bacterial cellulose (BC) nanocomposites using a bottom-up technique that allowed starch to be introduced into the cellulose network. The BC-starch mats were hot-pressed to obtain nanocomposites sheets. Morphological characterisation was carried out using Atomic Force Microscopy and Environmental Scanning Electron Microscopy. The images obtained from microscopy were then processed using image analysis. Network properties, such as mesh size and fibre orientation were characterised. Fracture surfaces of these new nanocomposites were analysed.
Mechanical Behavior of Composite Sandwich Structures Subjected to Low Velocity Impact – Experimental Testing and Finite Element Modeling
Authors: Rizov V. , Mladensky A.
Published: September 2018

Sandwich materials with a cellular foam core are increasingly used in engineering applications. The basic advantage of these materials is their high strength-weight ratio. However, sandwich structures are notoriously sensitive to failure by the application of highly localised external lateral loads. Therefore the proper design requires an understanding of the response of these materials to localised loads. The purpose of this work was the evaluation of the low velocity localised impact behaviour of sandwich structures made of glass-fibre reinforced composite laminate face sheets and polyvinylchloride (PVC) foam core. The impact tests were performed with a drop-weight rig. Beam and panel sandwich specimens were impacted using steel cylindrical and spherical impactors, respectively. During the testing, the specimens were supported by a stiff steel continuous substrate in order to avoid global bending. The load and deceleration histories were recorded during impact. A finite element model was developed to simulate the impact response. Results obtained by this model exhibit good correlation with the experimental data. It is shown that the model can be used to successfully predict the elastic-plastic response of sandwich composite structures subjected to low velocity localised impact.
The Influence of Barium Sulfate on the Mechanical Properties of Glass/Epoxy Resin Composite
Authors: Wang ZhiGang , Zhang FuQiang , Song Ning , Ni LiZhong
Published: September 2018

The aim of this study was to evaluate the influence of barium sulfate on the mechanical properties of glass/epoxy resin composite. Eight groups of glass fibre-reinforced resin bar and barium sulfate/epoxy resin bar specimens containing 0%, 9.7%, 13.9%, 17.7%, 21.2%, 24.4%, 27.3%, and 30.1 w.t% barium sulfate were fabricated. The three-point bending test and Charpy impact test were employed to measure the flexural strength, modulus, and impact strength of the composite. It was found that the flexural strength value increased about 30% from 0% (635.75 MPa) to 30.1% (822.82 MPa) as the amount of barium sulfate increased. The elastic modulus values of all group specimens varied from 23–27 GPa but there was no statistical significance among the groups (P = 0.524). The impact strength decreased noticeably with the addition of barium sulfate to the epoxy resin, while there was no significant difference among the filler-containing groups. In conclusion, barium sulfate reduced the impact strength of the resin; but on combining with glass fibre reinforcement, the barium sulfate improved the flexural strength of the composite.
Effect of Fillers on the Fire Retardant Properties of Intumescent Polypropylene Compounds
Authors: Faghihi Jalal , Morshedian Jalil , Ahmadi Shervin
Published: September 2018

The effects of fillers, including ammonium polyphosphate (APP), aluminium trihydrate (ATH) and talc, and the effect of polyethylene vinyl acetate (EVA) as an interfacial agent, were investigated on the flame retardant properties of intumescent polypropylene (PP), by using mechanical testing, to measure the tensile and Izod impact strengths, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and the limiting oxygen index (LOI) test method. SEM studies showed that the dispersion of flame retardant particles in the PP matrix improved with the use of EVA. Tensile strength decreased but elongation at break and impact resistance of PP/APP/EVA and PP/ATH/EVA composites increased by using 10 wt.% of EVA. Using 12 wt.% of talc in PP/APP/PA-6/EVA led to increasing impact resistance and decreasing tensile strength and elongation at break of the composite. EVA prevented the exudation of additives to the composite surface, and consequently the fire retardant properties of the composites improved. Talc increased fire protective performance due to the formation of a ceramic-like protective shield at the surface and increased residual mass at the end of the process. The results were interpreted by means of thermal decomposition, chemical reaction between components, and the formation of a protective layer at the surface on ignition.
Mechanical, Optical and Barrier Properties of Pa6/Nanoclay-Based Single- and Multilayer Blown Films
Authors: Poisson Charles , Guerengomba Josée , Lacrampe Marie-France , Krawczak Patricia , Gupta Bhuvanesh , Miri Valérie , Lefebvre Jean-Marc
Published: September 2018

The optimisation of food packaging films requires the films to be designed with excellent barrier properties to gases (usually water vapour and oxygen) and high mechanical and optical performances, without significant cost increase. Polymer nanocomposites may offer an interesting opportunity in this respect. This solution is studied in the present paper for both polyamide-6 (PA6) single-layer films and polyethylene/maleic anhydride grafted polyethylene/polyamide-6 (PE/PEgMAH/PA6) multilayer films. The addition of 2 wt.% of nanoclay in PA6 simultaneously improves the mechanical properties (tensile modulus, yield stress and strength), optical performances (gloss, haze and clarity) and oxygen impermeability. The processing conditions have no major influence on the studied properties, except for the optical properties. The cost increase induced by this solution is balanced by the benefits obtained in terms of overall improvement of film properties.
Comparison of Aluminium Hydroxide and Magnesium Hydroxide as Flame Retardants in Sebs-Based Composites
Authors: Xiao Wang-Dong , Kibble Kevin A.
Published: September 2018

The flame retardancy and mechanical properties of styrene-ethylene/butylene-styrene block copolymer (SEBS) based composites, containing paraffinic hydrocarbon extender oil filled SEBS (O-SEBS), blended with copolymer polypropylene (PP), and flame-retardant filler aluminium hydroxide (ATH) or magnesium hydroxide (MH) were investigated. Limiting Oxygen Index (LOI) values of both ATH and MH filled composites increased substantially as the amount of ATH and MH increased, respectively. Furthermore, the LOI values of the ATH system are higher than those of MH for the same addition level. When MH is introduced, progressively, into ATH-filled composites, and for a constant combined filler loading of 65 wt.%, LOI only decreases, when the ratio of MH to ATH exceeds 40%. Combining the two retardants, in the composites, may have a synergistic effect with respect to fire retardance. Tensile strength, up to 50 wt.% filler, and elongation at break of the composites decrease as the amount of filler increases. However, the elongation at break of the composites filled with MH is a little higher than that with ATH, but for tensile strength there is little difference between them. At filler loading greater than 50 wt.%, the tensile strength levels off but the% elongation is dramatically reduced. Introduction of MH in ATH filled composites leads to some variation in the mechanical properties of the composites. For a combined filler loading of 65 wt.%, the elongation at break increases from around 180 to 200% for a progressive increase in the ratio of MH to ATH up to 40% and there is a large increase in% elongation to around 300% when MH ratio reaches 55–60%, thereafter the% elongation falls. This effect may be linked to particle size distribution of the respective MH and ATH fillers. In contrast, there is little effect on the tensile strength. The thermogravimetric analysis (TGA) and differential TG (DTG) data show that ATH and MH increase the thermal stability of the SEBS-based composites.
Mechanical Properties and Flame Retardancy of Sebs-Based Composites Filled with Aluminium Hydroxide
Authors: Kibble Kevin A. , Xiao Wang-Dong
Published: September 2018

The flame retardancy and mechanical properties of styrene-ethylene/butylene-styrene block copolymer (SEBS) based composites, containing SEBS blended with a paraffinic hydrocarbon extender oil, copolymer polypropylene (PP), and aluminium hydroxide (ATH) or silane coupling agent surface-treated aluminium hydroxide (m-ATH) were investigated. A maleic anhydride-grafted SEBS (MA-SEBS) was used as a polymer modifier for some composites. As the amount of ATH or m-ATH increased the flame-retardancy of the composites improved, while the tensile strength and elongation at break decreased. When the oil-filled SEBS (O-SEBS) was partially replaced by MA-SEBS, the tensile strength of the composites increased, and elongation at break decreased. Furthermore, replacing O-SEBS with MA-SEBS and treating ATH with silane coupling agent (simultaneously) improved the tensile strength of the composites by a significant margin. The phase structure of the composites was characterised using scanning electron microscopy (SEM) and this revealed that particle-matrix interfacial bonding was improved through the addition of MA-SEBS. The stability of the composites was investigated by thermogravimetric analysis (TGA).
Validation of the Finite Element Method Applied to Isotactic Polypropylene Homopolymers
Authors: Martin J. , Malon H. , Castejon L.
Published: September 2018

The main aim of the present article is to validate results obtained using numerical techniques on an isotactic polypropylene homopolymer. With this in mind, results obtained by the finite element method (FEM) are compared with numerical results obtained using a free-fall tower. This comparison validates the FEM calculations, as differences between empirically and numerically obtained results are never greater than 9.84%.
Organophilic Layered Silicate Modified Vinylester-Urethane Hybrid Resins: Structure and Properties
Authors: Corobea M.-C. , Donescu D. , Grishchuk S. , Castellà N. , Apostolov A.A. , Karger-Kocsis J.
Published: September 2018

A commercial vinylester-urethane (VEUH) hybrid resin was modified with organophilic layered silicates (OLS), incorporated in various amounts (0.1 to 5 wt.%). As organophilic intercalants of the layered silicate (synthetic fluorohectorite) trimethyl dodecylamine (TMDA) and octadecylamine - N,N-bis[allyl(2-hydroxypropyl)ether] (OAE) served. The latter quaternary amine was expected to support the intercalation/exfoliation of the silicate by participating in the crosslinking reactions. Both OLS types became intercalated based on X-ray diffractograms (XRD). Dynamic-mechanical thermal analysis (DMTA) displayed a slight increase in the stiffness by adding OLS up to 2.5 wt.%. However, at 5wt% OLS content the stiffness of the nanocomposites was below that of the unfilled hybrid resin. The glass transition temperature (Tg) did not change practically with the OLS type and content. Fracture mechanical tests were performed on compact tension (CT) specimens. The fracture toughness (Kc) increased slightly, while the fracture energy (Gc) markedly with increasing OLS content. Unexpectedly, TMDA proved to be a more suitable intercalant than OAE. The failure mode of the specimens was studied in a scanning electron microscope (SEM) and discussed. In addition, the water sorption behavior of the OLS modified VEUHs was determined and the diffusion coefficients (D) deduced.
New Equipment and Approaches for Fabrication of Uniformly-Dispersed Nanoclay Cluster/Epoxy Composites
Authors: Chan Mo-lin , Lau Kin-tak , Ho Mei-po , Cheng Alvin , Wong Tsun-tat
Published: September 2018

The development of nanocomposites for different engineering applications has been going through a progressive period since the last decade. The miniaturization of devices and systems such as micro-electro-mechanical systems (MEMs) and nano-electro-mechanical systems (NEMs), has brought up the need of ultra-strong structural materials and composites. Research in nanoclay related polymer composites has been a hot topic in the past few years. It is believed that the use of this material to form composites is able to enhance the mechanical, thermal and electrical properties of Polyurethane (PU), Polyester (PE) and Epoxy. However, these composites have only achieved a small strength increment that is below expected potential. The difficulties are on how to produce uniformly-dispersed nanoclay/polymer composites and avoid clustering effect. In this project, a new experiment setup is proposed to mix nanoclay and epoxy together to form uniformly-dispersed nano-sized nanoclay cluster/ epoxy composites. In the experiment, it was found that the micro-hardness of the composites (with 5 wt.% of nanoclay) increased up to 50% under a controlled spinning, curing time and temperature environment.
Study of the Properties of Plasticised Poly(Lactic Acid) with Poly(1,3-Butylene Adipate)
Authors: Ning Wang , Xingxiang Zhang , Jiugao Yu , Jianming Fang
Published: September 2018

Poly(lactic acid) (PLA) is a biodegradable thermoplastic that can be produced from renewable resources, and so was considered as a major alternative to petroleum-based plastics for packaging applications. However, plasticisation of PLA was required in order to obtain films with sufficient flexibility. Poly(1, 3-butylene adipate) (PBA) was used as a novel plasticiser for PLA, and acetyltributyl citrate (ATBC) was used as the control. FTIR revealed that interaction took place between PLA and plasticiser. With an increasing plasticiser content, storage modulus and glass transition temperature decreased, but elongation at break increased. The elongation at break of PBA-plasticised PLA (PBA content 30 wt.%) could be above 600%, higher than that of ATBC-plasticised PLA (ATBC content 30 wt.%). Moreover, PBA was able to restrain thermally induced migration of plasticiser in plasticised PLA. It was also found that the migration rate of ATBC was directly proportional to the ATBC content in the blends. The rheology showed that the plasticiser could obviously decrease the shear viscosity and improve the fluidity of the blends. PBA was therefore recognised as a novel plasticiser for enhancing the properties of PLA. In particular, as a biodegradable polymer, PBA, when used as a plasticiser in PLA, can enhance migration resistance for its proper molecular weight. Moreover, the area of application of plasticised PLA is broadened.
In Situ Synthesis of Polystyrene/SiO2 Hybrid Composites via a 'Grafting Through' Strategy Based on Nitroxide-mediated Radical Polymerisation
Authors: Wang Yunpu , Shen Yongqian , Pei Xiaowei , Zhang Wenjuan , Wei Yuli , Yang Chao
Published: September 2018

Polymer-grafted nanosilica hybrid composites that possess a hard backbone of nanosilica and a soft shell of brush-like polystyrene (PSt) were prepared via a ‘grafting through’ strategy based on nitroxide-mediated radical polymerisation (NMRP) using 2,2,6,6-tetramethylpiperidine-iV-oxyl (TEMPO) as the mediator. Two steps were used to graft PSt chains to the surface of nanosilica: anchoring of vinyltrimethoxysilane onto the surface of nanosilica, and then using TEMPO to trap the radicals produced by the reaction of benzoyl peroxide (BPO) with styrene and the vinyl group in grafted vinyltrimethoxysilane molecules. Finally, well-controlled molecular weight (Mn) and narrow molecular weight distributions (Mw/Mn) of PSt chains were grown from the surface of nanosilica. The prepared PSt-g–SiO2 hybrid particles have been extensively characterised by FTIR, XPS, TGA, and TEM.
Multiscale Carbon Nanotube-Carbon Fiber Reinforcement for Advanced Epoxy Composites with High Interfacial strength
Authors: Mei Lei , Li Yibin , Wang Rongguo , Wang Chao , Peng Qingyu , He Xiaodong
Published: September 2018

In this study, carbon nanotubes were chemically grafted on carbon fibers using PAMAM functionalization. Single-fiber composites with the carbon nanotube/carbon fiber (CNT/CF) multi-scale reinforcement were fabricated to examine the influence of local nanotube reinforcement on load transfer at the fiber/matrix interface. Molecular simulations of the epoxy resin composites with a CNT/CF multi-scale reinforcement and an unsized CF were performed employing Materials Studio 4.0 software. Results show that the interfacial shearing strength (IFSS) of the CNT/CF composite is up to 116.98 MPa, an increment of 170% in comparison with that of the unsized T300 CF composite. The results of molecular simulations show that interaction energy of CNT/CF multi-scale composite is up to 929.83 kcal/mol, which is 2.7 times higher than that of the unsized one. This significant enhancement of interfacial shear strength can be attributed to two aspects: (i) Van der Waals binding and mechanical interlocking increase due to the CNTs addition, (ii) chemical bonding and surface wetting increase caused by the layer of PAMAM dendrimers.
Molecular Dynamic Simulation of Sword-Sheath Extraction Behavior in CNT Reinforced Composite
Authors: Yang Lin , Tong Liyong , He Xiaodong
Published: September 2018

In the pull-out testing of a multi-walled carbon nanotube (MWNT) in MWNT reinforced composites, sword-sheath extraction is an observed mechanism, in which at least the outermost layer of the MWNT remains connected to its surrounding matrix whereas the inner layer(s) slide relatively. This paper presents a MD simulation to investigate the sword-sheath extraction behavior and then compare with normal debonding extraction of a whole MWNT. It is identified that the two extractions have similar pullout force-displacement behavior with sword-sheath requiring less peak forces than debonding extraction.
Modeling of the Damping Properties of Unidirectional Carbon Fibre Composites
Authors: Gao Ying , Li Yibin , Hong Yi , Zhang Hongming , He xiaodong
Published: September 2018

Vibration and noise are harmful to mechanical systems and the environment. Using high damping materials or structures is a very effective way to control vibration and lower noise. The paper presents modeling of the damping properties of unidirectional carbon fibre reinforced epoxy resin composite materials, including natural frequencies, damping loss factors and mode shapes. Damping modeling is implemented using a finite element method based on mode analysis theory and strain energy method. The influences of fibre orientation on the natural frequencies and damping loss factors for the first four modes are analyzed in the case of cantilever. The results showed that natural frequencies decrease with fibre orientation increased. The influences of fibre orientation on the damping loss factors are different with fibre orientation changed.
A Novel Silicon-containing Ethynylarene Resin as Heat-resistant Thermoset
Authors: Shi Song , Yang Ming , Luo Zhenhua , Han Weijian , Hu Jidong , Zhao Tong , Zhang Dahai
Published: September 2018

A series of novel processable and heat-resistant silicon-containing resins (PSA-E resins) were successfully synthesized by the reaction of 1,3,5-tris-(4-ethynylphenyl)benzene (TEPHB) with silylene-acetylene polymer (PSA resin) with high yields. The molecular structure, thermal curing processes and thermal properties were characterized by FTIR, 1HNMR, GPC, DSC and TGA. The results indicated that these novel resins could be melted at room temperature and thermally cured at 200–250 °C with low exothermal heat. Owing to the complete crosslinking of ethynyl groups, the Td5 (temperature of 5% weight loss) for all the thermosets are above 500 °C, and the overall char yields were above 87% at 900 °C under nitrogen.
Effects of Tougheners and Thermo-oxidative Aging on Bending Properties of Carbon Fiber/bis-maleimide Composites
Authors: Lv Xinying , Wang Rongguo , Liu Wenbo , Jiang Long
Published: September 2018

The composites with carbon fiber as the reinforcement, and three toughened bis-maleimide (BMI) resins as matrix were fabricated and then characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy with combination of the bending test in order to evaluate the thermal stability of these composites undergone thermal-oxidative aging at 150 °C up to 1000 h and to investigate the effect of toughener species on bending properties. The results showed that the BMI toughened by diallyl ether of bisphenol A (DABPA) had higher bending strength and good thermal stability because the DABPA has two reactive points that can increase the crosslinking density of cured BMI matrix via crosslinking reaction. FTIR indicated that three toughened BMI resins had some chemical changes after thermal-oxidative aging at 150 °C for 1000 h, but the morphology of fractured surface by SEM and bending test revealed that these changes showed slight effects on the bending strength and interfacial adhesion between carbon fiber and BMI matrix; the main fracture models of the composites during bending tests were fiber pullout and fiber fracture.
Effect of Additives on Mechanical Properties and Photo-Stability of Filament-Wound Glass Fiber Reinforced Epoxy Pipes
Authors: Pechyen C. , Atong D. , Aht-Ong D.
Published: September 2018

This paper studied the effects of 4 types of additives, UV-absorber, antioxidant, carbon black, and flame retardant, on mechanical properties and UV- stability of glass fiber reinforced epoxy (GRE) pipes prepared by filament winding process using a MTHPA (Methyl Tetrahydrophthalic Anhydride) as a catalyst. The amount of additives used was varied from 0 – 10 %w/w. The central composite design (CDD) was employed to experimentally design the formulation of GRE pipes. The photodegradation of the GRE pipes was performed by an outdoor exposure and simulated condition in Q-UV Lamp. The progress of photodegradation was followed by determining the changes in mechanical properties, physical properties and appearance, as a function of exposure time. The results showed that the GRE pipes containing 2, 1,3, and 10% w/w of UV-absorber, antioxidant, carbon black, and flame retardant, respectively had better mechanical properties than the others over period of exposure time. Similar results were observed in both outdoor and accelerated tests. In addition, it was found that UV exposure could actually improve short-term mechanical properties due to postcuring phenomenon. Under the accelerated condition, it was found that upon increasing the Q-UV exposure time, the physical properties in terms of the density, color, and gloss were decreased. Color changes involved initial fading followed by subsequent increased level of yellowing. The decrease in density and gloss values were attributed to the surface degradation induced by UV-irradiation. As evidenced by SEM micrographs, a substantial degree of catering and cracking was observed, especially after 10 years of Q-UV exposure.