Effects of chicken eggshell filler size on the processing,mechanical and thermal properties of PVC matrix composite

The effects of filler particle size of poly(vinyl chloride)/chicken eggshell powder (PVC/ESP) composites on the processing, tensile properties, morphology and thermal degradation were investigated. The mixing of composites was done using Rheomix internal mixer. The processing torque of PVC/ESP composite at a particle of 0.2 μm exhibits lower processing torque compared to that at a particle size of 7 μm due to the dispersive resistance from larger ESP filler particles. Good interfacial adhesion exists between the filler and matrix in composites prepared via a filler particle size of 0.2 μm, which has improved the tensile strength and modulus of PVC/ESP composite compared to a filler particle size of 7 μm as justified from FESEM images on the tensile fracture surface of the composites. Thermogravimetric analysis results show that the filler particle size of 0.2 μm composite exhibits higher thermal stability compared to the filler particle size of 7 μm composite.     

Effect of single‐mineral filler and hybrid‐mineral filler additives on the properties of polypropylene composites

The present study was carried out to determine the filler characteristics and to investigate the effects of three types of mineral fillers (CaCO₃, silica, and mica) and filler loadings (10–40 wt%) on the properties of polypropylene (PP) composites. The characteristics of the particulate fillers, such as mean particle size, particle size distribution, aspect ratio, shape, and degree of crystallinity were identified. In terms of mechanical properties, for all of the filled PP composites, Young's modulus increased, whereas tensile strength and strain at break decreased as the filler loading increased. However, 10 wt% of mica in a PP composite showed a tensile strength comparable with that of unfilled PP. Greater tensile strength of mica/PP composites compared to that of the other composites was observed because of lower percentages of voids and a higher aspect ratio of the filler. Mica/PP also exhibited a lower coefficient of thermal expansion (CTE) compared to that of the other composites. This difference was due to a lower degree of crystallinity of the filler and the CTE value of the mica filler. Scanning electron microscopy was used to examine the structure of fracture surfaces, and there was a gradual change in tensile fracture behavior from ductile to brittle as the filler loading increased. The nucleating ability of the fillers was studied with differential scanning calorimetry, and a drop in crystallinity of the composites was observed with the addition of mineral filler. Studies on the hybridization effect of different (silica and mica) filler ratios on the properties of PP hybrid composites showed that the addition of mica to silica‐PP composites enhanced their tensile strength and modulus. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

聚丙烯/鳞片石墨导热复合材料的制备及性能

以聚丙烯(PP)为基体,鳞片石墨(FG)为填料,通过添加偶联剂、开炼机混炼、模压成型的方法,制备了具有较高热导率和优良力学性能的PP/FG导热复合材料。考察了硅烷偶联剂的品种及用量、FG的粒径及含量对复合材料热导率和力学性能的影响。结果显示,使用偶联剂处理的FG对复合材料的力学性能具有一定的增强作用,但是材料的热导率降低;当KH 550添加量为FG含量的1%时,材料的力学性能最好;随着FG粒径的增大,材料的热导率明显提高,力学性能相应下降,粒径为17μm的FG与148μm的FG制备的复合材料相比,热导率提高了52.3%,拉伸强度和弯曲强度分别由34.4 MPa和51.5 MPa下降到25.1 MPa和43.0 MPa;随着FG含量的增加,材料的热导率增大,当17μm的FG含量为70%时,材料的热导率是纯PP的22.1倍,拉伸弹性模量和弯曲弹性模量也随之增大,断裂拉伸应变和断裂弯曲应变减小,拉伸强度和弯曲强度先减小后增大,并且在FG含量为20%时降到最低。     

Deformation mechanism of polypropylene composites filled with magnesium hydroxide

The fracture behavior and deformation mechanism of polypropylene (PP) composites filled with magnesium hydroxide [Mg(OH)₂] were investigated. The incorporation of Mg(OH)₂ particles into the PP matrix led to an increase in Young's modulus and a significant reduction in the tensile yield strength and elongation at break. Surface modification on filler particles with stearic acid could reduce the interfacial adhesion between the filler and PP matrix and improve the stress transferability. The deformation mechanism of the Mg(OH)₂/PP composites depended on the interfacial adhesion and the deformability of ligaments between microvoids caused by debonding. The deformability of the ligaments could be significantly improved by surface modification on the particle surface. The dependence of the deformation behavior of the Mg(OH)₂/PP composites on the filler content was in accordance with percolation theory. The agglomeration of microvoids and fibrillation of ligaments in the PP composites with excessive filler content indicated the weak resistance of the polymer matrix to crack propagation and premature fracture in a brittle manner. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1922–1930, 2005     

Effects of palm ash loading and maleated natural rubber as a coupling agent on the properties of palm‐ash‐filled natural rubber composites

Natural rubber composites were prepared by the incorporation of palm ash at different loadings into a natural rubber matrix with a laboratory‐size two‐roll mill (160 × 320 mm²) maintained at 70 ± 5°C in accordance with the method described by ASTM D 3184–89. A coupling agent, maleated natural rubber (MANR), was used to improve the mechanical properties of the natural rubber composites. The results indicated that the scorch time and cure time decreased with increasing filler loading, whereas the maximum torque exhibited an increasing trend. Increasing the palm ash loading increased the tensile modulus, but the tensile strength, fatigue life, and elongation at break decreased. The rubber–filler interactions of the composites decreased with increasing filler loading. Scanning electron microscopy of the tensile fracture surfaces of the composites and rubber–filler interaction studies showed that the presence of MANR enhanced the interfacial interaction of the palm ash filler and natural rubber matrix. The presence of MANR also enhanced the tensile properties and fatigue life of palm‐ash‐filled natural rubber composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Mechanical properties of talc-filled polypropylene. Influence of filler content,filler particle size and quality of dispersion

Mechanical properties of polypropylene-talc composites are measured as a function of talc concentration up to 40 wt.-%, Young's modulus of filled polypropylene shows linear increase with talc concentration up to double the value of unfilled polymer. Yield stress and Charpy notch toughness decrease with increasing talc content below matrix level at the highest filler content. Composite ultimate tensile elongation and tensile impact strength decrease sharply beginning at the lowest filler concentration. The influence of the talc particle size on the mechanical properties, especially composite toughness, mentioned above, is investigated. Four type of talc were used. Notch toughness decreases according to a linear dependence with mean size of talc particles. Evaluating impact strength possible content of agglomerates of filler and other additions is necessary to be included: tensile impact strength gives slow linear dependence with increasing content of filler particles and/or agglomerates above about 10 μm. The influence of talc particle size on the toughness of filled polypropylene becomes strong if the rubber particles are present.     

Curing Characteristics and Mechanical Properties of Oil Palm Wood Flour Reinforced Epoxidized Natural Rubber Composites

Abstract

The paper reports on the curing characteristics and mechanical properties of oil palm wood flour (OPWF) reinforced epoxidized natural rubber (ENR) composites. Three sizes of OPWF at different filler loadings were compounded with a two roll mill. The cure (t ₉₀) and scorch times of all filler size decrease with increasing OPWF loading. Increasing OPWF loading in ENR compound resulted in reduction of tensile strength and elongation at break but increased tensile modulus, tear strength and hardness. The composites filled with smaller OPWF size showed higher tensile strength, tensile modulus and tear strength. Scanning electron microscope (SEM) micrographs showed that at lower filler loading the fracture of composites occurred mainly due to the breakage of fibre with minimum pull-out of fibres from the matrix. However as the filler loading is increased, the fibre pull-out became very prominent due to the lack of adhesion between fibre and rubber matrix.     

Tensile behavior of polyolefin composites: the effect of matrix parameters

Polyolefin composites were prepared from 14 PE matrices and three different mineral fillers (montmorillonite, palygorskite and glass microspheres) via melt compounding in an extruder. Mechanical properties of the obtained systems were analyzed with emphasis on elongation at break and conditions for ductile/brittle failure were determined. When filler content is raised beyond a certain “critical” value, tensile properties are dramatically altered and transition occurs from ductile behavior to brittle fracture. This transition is displayed by a well‐defined “step” on the plot of strain at break versus concentration of particles. The value of “critical filler content” was found to depend mainly on level of crystallinity of a matrix while other parameters (chemical nature of filler particles, their size, shape and surface treatment) are less significant. “Critical filler content” will decrease with growth of crystallinity of a polymer and with highly crystalline HDPEs it is as low as 2–8 vol %. Otherwise, with noncrystallizing and low‐crystalline polymers elongation at break decreases gradually with concentration of mineral particles and ductile type deformation is maintained at fairly large filler fractions. The results presented here will be useful for a proper selection of a matrix polymer in composites with mineral fillers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43819.     

Chemical Modification of Chitosan-Filled Polypropylene (PP) Composites: The Effect of 3-Aminopropyltriethoxysilane on Mechanical and Thermal Properties

Chitosan was used as filler in polypropylene (PP) polymer. In order to improve compatibility between chitosan and PP, chitosan was chemically modified with 3-aminopropyltriethoxysilane (3-APE). The results show that the increasing of filler content decreased tensile strength and elongation at break, but increased Young's modulus of composites. The treated composites exhibit higher tensile strength and Young's modulus, but lower elongation at break compared untreated composites. The addition of 3-APE has improved thermal properties such as thermal stability and crystallinity of treated composites. SEM study of the tensile fracture surface of treated composites shows better interfacial interaction and adhesion between the chitosan-PP matrix.     

Poly(phenylene oxide) composites containing crosslinked polystyrene microspheres. I. Stress–strain properties

The stress–strain properties of poly(2,6-dimethyl-1,4-phenylene oxide)/polystyrene composites containing crosslinked polystyrene microspheres have been measured at strain rates of 0.167, 1.67, and 16.7 min^?1. It is found that Young's modulus almost has no increase with the filler content. The elongation at break and tensile strength decrease with the volume fraction of the filler, but both tend to flatten out at the volume fraction ν_f > 0.25 at the strain rate of 1.67 min^?1. The two ultimate tensile properties also have maximum values in the relationship with strain rate at the same filler concentration and strain rate conditions. Considering that elongation can be brought about by both matrix and filler, the well-known equation of elongation at break becomes     

Lewis acidic polypropylene for compatibilization of polypropylene/microsilica composites

Polypropylene (PP) was compounded with submicron size silica filler particles (microsilica, μSi) up to 30 wt‐%. In addition, three external compatibilizers, with characteristic functionalities, were studied to examine their influence in the mechanical properties of the PP/μSi composites. As a result, the modulus of the composite increased while the other tensile values deteriorated in correlation with increased filler concentration. The addition of an external compatibilizer reduced this deterioration, but the reduction was dependent on the type of the compatibilizer used. The influence of an acid functionalized compatibilizer was unsubstantial while the fluorosilane and the Lewis acidic phenylsilane functionalized polypropylenes acted as effective compatibilizers. In addition to examining the tensile properties, the toughness of the composites was evaluated as well. The microsilica filler was found to act as toughening agent since the Brittle‐to‐Ductile transition point of the composite increased by 2‐3 orders of magnitude at high filler concentrations. However, this increase in the toughness was rapidly lost when an effective compatibilizer was used to bind the filler with the matrix. This observation was consistent with the common understanding of the filler toughening mechanism, where particle‐matrix debonding is a prerequisite for facilitating the plastic stretch of the polymer ligaments between filler particles. In our case, however, the few filler aggregates in the polymer matrix also played a crucial role. While in uncompatibilized composites the filler aggregates remained passive (could not be seen at the fracture surface), the addition of an effective compatibilizer activated these aggregates to promote crack initiation and/or propagation. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Lauric acid coated fly ash as a reinforcement in recycled polymer matrix composites

Sustainable composites were developed from fly ash (FA) and recycled polypropylene (R) with lauric acid (LA) as the coupling agent. The FA particles were surface‐coated with 1, 2, 3, and 5 wt % LA, and the coating on the FA particles was verified by transmission electron microscopy and Fourier transform infrared spectroscopy. R and LA‐coated FA particles were melt‐mixed in a 1:1 weight ratio to achieve a high‐filler‐loaded composite. The flexural, impact, nanoindentation, and fracture surface analyses were carried out to examine the properties of the composites. The flexural strength and modulus values increased in the 2 wt % LA‐coated FA/R composites by 6 and 50%, respectively, compared to the values of the uncoated FA/R composites, whereas the impact strength increased considerably by 119% in the 1 wt % LA‐coated composites. Nanoindentation tests also showed an increase in the mechanical properties in the case of the 1 and 2 wt % LA‐coated composites in comparison to the uncoated ones. Fracture surface studies done by scanning electron microscopy revealed improved interfacial interactions between the filler and matrix in the presence of the LA coupling agent. X‐ray diffraction (XRD) studies indicated reorientations of the polymer chains in the presence of different concentrations of the LA coupling agent; this resulted into different crystallinities and crystallite sizes. Differential scanning calorimetry showed a significant difference in the crystalline peaks of the composites, and this corroborated well with the XRD observations. LA, thus, significantly influenced the structural properties of the composites, and this, in turn, influenced their mechanical and thermal properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41586.     

Properties of Paper Sludge Filled Polypropylene (PP)/Ethylene Propylene Diene Terpolymer (EPDM) Composites: The Effect of Silane-Based Coupling Agent

Paper sludge was used as a filler in PP/EPDM composites and 3-aminopropyl triethoxysilane (3-APE) was used in this study as a coupling agent. The effects of filler loading and 3-APE on the mechanical properties, water absorption, morphology, and thermal properties of the composites were investigated. It was found that incorporation of a silane coupling agent (3-APE) increased the stabilization (equilibrium) torque, tensile strength, and Young's modulus but decreased the elongation at break and water absorption. Scanning electron microscopy (SEM) study of the tensile fracture surface of the composites indicated that the presence of 3-APE increased the interfacial interaction between paper sludge and PP/EPDM matrix. The addition of a silane coupling agent also increased the crystallinity of PP and thermal stability of PP/EPDM/PS composites.     

Mechanical properties of hydroxyapatite‐filled ethylene vinyl acetate copolymer composites: Effect of particle size and morphology

Pliable and bioactive composites made of hydroxyapatite (HAP) and ethylene vinyl acetate (EVA) copolymer were developed for the repair of defective cranium. This article describes the mechanical properties of HAP–EVA composites. The effects of HAP particle size and morphology of HAP on the properties of resultant composites were investigated using various techniques. It was found that the composites containing smaller HAP particles had higher values of tensile modulus, flexural modulus, and impact strength. Examination of the fracture surfaces revealed that only a mechanical bond existed between the filler and the matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Rheological,thermal, and mechanical characterization of fly ash‐thermoplastic composites with different coupling agents

Composite materials were prepared by mixing fly ash obtained from biomass combustion as filler and isotactic polypropylene (PP) as matrix. Three silane‐type coupling agents mainly differing in the size of their functional groups were used to improve the compatibility between both components. Uniaxial tensile tests showed that the incorporation of untreated ash into PP led to stiffer but also more brittle and weaker materials, as Young's modulus significantly increased and tensile strength and elongation at break decreased. Furthermore, an enhancement in storage and loss moduli as well as in composite viscosity was observed with the addition of fly ash. Hardness tests and thermal and fracture surface analyzes revealed tensile test results similar to those mentioned earlier. In summary, after analyzing the effects of the three silanes on mechanical, thermal, morphological, and rheological properties, the silane containing the vinyl functional group (XL10) was selected as the most appropriate for the PP/ash composites investigated. POLYM. COMPOS., 31:1722–1730, 2010. © 2010 Society of Plastics Engineers.     

Thermal and mechanical properties of aluminum powder-filled high-density polyethylene composites

Thermal conductivity and mechanical properties such as tensile strength, elongation at break, and modulus of elasticity of aluminum powder-filled high-density polyethylene composites are investigated experimentally in the range of filler content 0–33% by volume for thermal conductivity and 0–50% by volume for mechanical properties. Experimental results from thermal conductivity measurements show a region of low particle content, 0–12% by volume, where the particles are distributed homogeneously in the polymer matrix and are not interacting with each other; in this region most of the thermal conductivity models for two-phase systems are applicable. At higher particle content, the filler tends to form ag-glomerates and conductive chains resulting in a rapid increase in thermal conductivity. The model developed by Agari and Uno estimates the thermal conductivity in this region. Tensile strength and elongation at break decreased with increasing aluminum particles content, which is attributed to the introduction of discontinuities in the structure. Modulus of elasticity increased up to around 12% volume content of aluminum particles. Einstein's equation, which assumes perfect adhesion between the filler particles and the matrix, explains the experimental results in this region quite well. For particle content higher than 30%, a decrease in the modulus of elasticity is observed which may be attributed to the formation of cavities around filler particles during stretching in tensile tests. © 1996 John Wiley & Sons, Inc.     

Preparation and characterization of polypropylene/serpentine composites

Composites of serpentine and polypropylene (PP) were prepared by twin‐screw extrusion. Serpentine was collected as rocks from the Ankara–Beynam region and ground into powder with an average particle size of about 3 μm for composite production. Both as‐received (rock) and powdered serpentine were characterized. A silane coupling agent (SCA), γ‐aminopropyl triethoxy silane, was used for the surface treatment of serpentine. Mechanical properties of the composites were measured in terms of impact strength, elastic modulus, stress at yield, stress at break, and percentage strain at break. The addition of serpentine was found to have a profound effect on the reinforcement of the PP matrix. Because of the stronger interactions at the interphase induced by SCA treatment, mechanical properties were improved further in comparison with the untreated composites. Similar thermal and morphological behaviors were recorded for the composites with and without surface treatment. Thermal studies showed an increase in both melting temperature and percentage crystallinity of the composites. Scanning electron microscopy analysis revealed that homogeneous distribution of filler was observed at low filler contents, but a certain extent of agglomeration was also seen at high filler loadings. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

The Effect of Waste Office White Paper Content and Size on the Mechanical and Thermal Properties of Low-Density Polyethylene (LDPE) Composites

The effect of waste office white paper (WOWP) loading and size on mechanical properties, morphology and thermal properties of LDPE/WOWP composites were investigated. The results showed that increasing of WOWP loading has increased tensile strength and Young's modulus but decreased elongation at break of composites. LDPE/WOWP composites with smaller particle size (31 μm) have higher mechanical properties. Thermal analysis results of composites with particle size (31 μm) show higher thermal stability and crystallinity than composites with particle size (77 μm). Scanning electron microscope (SEM) micrograph indicates that the smaller particle size of filler has better interaction with LDPE matrix.     

Fire-retarding polypropylene with magnesium hydroxide

Four types of magnesium hydroxide with different particle and crystallite sizes and different degrees of agglomeration were added at amounts up to 60% by weight to polypropylene to obtain a series of composites. The burning characteristics, tensile yield strength, flexural modulus, notched Izod impact strength, and melt flow index of the resulting composites were measured. Magnesium hydroxide coated with sodium stearate was found to give an increased melt flow index and impact strength to the composites as compared to values obtained with uncoated magnesium hydroxide. Incorporation of not less than about 57% by weight of magnesium hydroxide made the composite nonflammable, but at the same time considerably reduced its impact, flexural, and tensile yield strengths. As the amount of magnesium hydroxide filler was increased, the tensile yield strength and flexural strength of the composite proportionally decreased while the flexural modulus increased. The impact strength reached a maximum value when the amount of incorporation was 30% by weight. The lower the degree of agglomeration of the magnesium hydroxide filler and the greater the crystallite size within the range to about 2μm, the better were the mechanical properties of the composite.     

Dynamic mechanical behaviour of polyamide 11/Barium titanate ferroelectric composites

Dynamic mechanical analysis and tensile test have been used to characterize the mechanical behaviour of hybrid composites. Barium titanate (BaTiO₃) is the submicron filler and polyamide 11 (PA 11) the matrix. The influence of volume fraction and particles size (ranging from 100 nm to 700 nm) of the inorganic phase on the composites mechanical properties have been checked. BaTiO₃ dispersion in the matrix increases the tensile modulus of the composites and an evolution from ductile to fragile is observed for volume fractions above 12 vol%. The volume fraction dependence of the glassy shear modulus is well described by the Hashin and Shtrikman model indicative of an interaction lack between the organic and inorganic phases. The decrease of the glassy shear modulus with the filler size has been associated with the existence of softer organic/inorganic interfaces, in agreement with the previous hypothesis. The non linear variation of the rubbery modulus versus particles content is well described by the rubber elasticity model applied to a hydrogen bond network.