Optimum Filler Loading Research Articles

Mechanical properties and thermal conductivity of epoxy composites enhanced by h-BN/RGO and mh-BN/GO hybrid filler for microelectronics packaging application

In recent years, significant interest has been focused on fabricating epoxy-based hybrid composite with a high thermal conductivity at optimum filler loading. As epoxy usually has a low thermal conductivity, the high intrinsic thermal conducting fillers such as h-BN, GO and RGO are incorporated. In this research, we report the epoxy-based hybrid composites with an enhanced thermal conductivity through silane-modified h-BN (mh-BN) with RGO. The sample containing 44.5 wt% (40 wt% mh-BN and 4.5 wt% RGO) hybrid filler exhibited the highest thermal conductivity (1.416 W/mK) which was 7 times that of pristine epoxy (0.21 W/mK). The thermal conductivities of RGO with unmodified h-BN (0.789 W/mK), GO with mh-BN (0.769 W/mK) and GO with unmodified h-BN (0.713) at 44.5 wt% loading are also reported. Comparison property studies of these above-mentioned four hybrid composites are described by lap shear strength, flexural strength, impact strength and thermogravimetric analysis. The fabricated hybrid composites exhibit outstanding performance in lap shear strength, thermal stability, and slightly reduced impact and flexural strength, which makes it as relevant for electronics packaging application such semiconductors, integrated circuit packaging, optoelectronics and also can attest potentiality in structural energy storage application. The atomic force microscopy and scanning electron microscopy verified the surface roughness and morphology of two optimized compositions, i.e., mh-BN with RGO and h-BN with RGO with the epoxy matrix. Also, Maxwell, Hashin–Shtrikmann and series equations are used to verify the obtained experimental value.

Influence of Pyrolytic Carbon Black Prepared from Waste Tires on Mechanical Properties of Natural Rubber Vulcanizates

This research aimed to investigate the possibility of pyrolytic carbon black (PCB) used as filler in natural rubber (NR) and its effect on Mooney viscosity, cure characteristics and mechanical properties compared with commercial carbon black (N774). The results revealed that Mooney viscosity, stiffness and heat build-up tended to increase with increasing both PCB and N774 loading, whereas elongation at break decreased. However, the maximum tensile and tear strengths appeared at the optimum filler loading for both PCB and N774. At similar filler content, PCB-filled NR compounds have higher cure time, heat build-up and thermal resistance. Nevertheless, they exhibited lower Mooney viscosity and mechanical properties compared to N774-filled NR. Finally, it can be concluded that PCB could be utilized as filler in NR compound to act as semi-reinforcing filler and was classified as a filler to reduce costs.

Comparative studies of thermo-mechanical and morphological properties of polylactic acid/fumed silica/clay (1.28E) and polylactic acid/fumed silica/clay (1.34TCN) nanocomposites

In this study, nanocomposites were prepared using polylactic acid (PLA), fumed silica (fsi) and nanoclay through solution-intercalation film-casting technique. Thermo-mechanical and morphological properties of developed nanocomposites were successively characterized by scanning electron microscopy (SEM) analysis, tensile test and thermogravimetric analysis (TGA). Throughout the findings, it proved that 2 wt% of clays was the optimum filler loading compared to 5 and 10 wt% in the PLA-fsi-clay nanocomposites. Furthermore, among the clays used, clay (1.28E) showed the better performance compared to clay (1.34TCN) to be introduced in the nanocomposites. The incorporation of 2 wt% of clay (1.28E) showed the best compatibility with PLA-fsi matrix with smooth surface. Besides, 2 wt% of PLA-fsi-clay (1.28E) nanocomposite showed the highest tensile strength and modulus. TGA result showed that 2 wt% of clays especially clay (1.28E) had the highest thermal stability. Both clay and fumed silica were well intercalated with PLA matrix enhanced the thermo-mechanical and morphological properties of the nanocomposites.

Investigating morphological and performance deterioration of injection-molded rice husk–polypropylene composites due to various liquid uptakes

ABSTRACTSystematic investigations for the tensile strengths, tensile moduli, flexural strengths, flexural moduli, and impact strengths of various reinforced conditions of rice husk–polypropylene composites under the effect of different liquids uptakes were carried out. Three different liquids, i.e., lubricant oil, sea water, and distilled water, were utilized in this work to investigate their effects on the composites’ mechanical performance. Moreover, morphological analysis of the designed composites was also carried out. Various fiber loadings at 35, 40, 45, 50, and 55 wt% have been designed and investigated. The rice husk–polypropylene composites have been prepared by injection molding, and struktol was used as an additive. The composites were immersed in three different liquids—lubricant oil, sea water, and distilled water—for 4 weeks. The water uptake of rice husk–polypropylene composites for distilled water was the highest compared to lubricant oil and sea water. Moreover, results have demonstrated that mechanical properties of composites immersed in sea water were the best, followed by those immersed in lubricant oil, and then those immersed in distilled water. In addition, it was observed that more voids and pull-out existed in composites immersed in lubricant oil, followed by those immersed in distilled water, and then those immersed in sea water. Tensile moduli showed a reduction trend for all composites with increasing filler loading. However, flexural moduli improved as the filler loading increased. Also, results here demonstrated an optimum filler loading condition for each particular mechanical property of rice husk–polypropylene composites.

Preparation, Characterization, and Dielectric Properties of PP/CaTiO3 Composites for Microwave Substrate Applications

Calcium titanate (CaTiO3) filled polypropylene (PP) composites have been fabricated through compression molding method. The phase purity of the PP/CaTiO3 composites was studied using X‐ray diffraction studies. Scanning electron microscopy technique has been employed to study the dispersion of the particulate filler in the PP matrix. The dielectric constant and loss tangent of the composites were measured at X‐band frequency region using waveguide cavity perturbation technique. PP/CaTiO3 composite has an effective dielectric constant of 11.74 and loss tangent 0.007 at optimum filler loading. The experimental dielectric constant of filled composites was compared with theoretically predicted dielectric constant values obtained using different modeling approaches. The linear coefficient of thermal expansion of PP/CaTiO3 composites was studied using thermomechanical analyzer.

Influence of Conducting Polymer as Filler and Matrix on the Spectral, Morphological and Fluorescent Properties of Sonochemically Intercalated poly(o-phenylenediamine)/Montmorillonite Nanocomposites.

Nanocomposites consisting of spatially confined polymeric chains are of great interest due to their application in optoelectronic and photonics devices. Polymer layered silicate nanocomposites have attracted much attention in industry as well as academia owing to their remarkable physical and chemical properties as compared to conventional polymer nanocomposites. In present study, comparative investigation of the in-situ polymerization of poly(ophenylenediamine) intercalated montmorillonite has been done via two methods i.e using poly(o-phenylenediamine) as filler for MMT in one case and as matrix in the other. Intercalation and in-situ polymerization was confirmed by FT-IR, UV-Visible spectroscopy and XRD studies. TEM and optical microscopy studies confirmed the self-assembled morphology of nanocomposites while the fluorescence properties revealed that controlled emission could be achieved by confining poly(o-phenylenediamine) in MMT galleries. Intercalation and in-situ polymerization of o-phenylenediamine within MMT was successfully carried out using sonochemical technique. The growth of conducting polymers in the interlayer region of the clays has been shown to dramatically improve the properties of conducting polymers. Also, the loading of the polymer in the MMT has shown to influence the optical properties of the nanocomposite. IR spectra and XRD analysis confirmed the intercalation of POPD and its polymerization within the clay galleries. UV spectra revealed the doped state of POPD within clay galleries. Highest oscillator strength of 0.0137 was observed for POPD:MMT-1:0.25. Spherical self-assembled morphology was attained for POPD:MMT-1:0.25. XRD revealed major shift of 82.5 Å for the nanocomposite POPD:MMT-1:1, POPD:MMT-1:0.5 and MMT:POPD-1:0.25. Blue shift of 20 nm was noticed in the fluorescence spectra of POPD:MMT-1:0.25 and POPD:MMT-1:0.5 which was correlated to the intense interaction between NH of POPD with SiO of MMT. Highest quantum yield of 0.345 was achieved in case of POPD:MMT-1:0.25. The gallery confinement was found to control the optical as well as morphological characteristics of the nanocomposite. The controlled growth of POPD chains and their minimum aggregation resulted in the formation of self-assembled morphology. Thus, by choosing the optimum filler loading and by controlling its interaction with the matrix, nanocomposites with controlled architecture can be designed. It can be concluded that intercalation and exfoliation of nanocomposites largely depends on the experimental conditions such as type of conducting monomer, clay and organic modifier etc. The preparation technique and processing conditions influence the overall properties of the nanocomposites. Thus, by choosing the optimum filler loading and by controlling its interaction with the matrix, nanocomposites with controlled architecture can be designed. Few relevant patents to the topic have been reviewed and cited.

Effect of Filler Loading on Curing Characteristic and Tensile Properties of Palygorskite Natural Rubber Nanocomposites

This work investigates the effect of filler loading on curing characteristics and tensile properties of palygorskite (PAL) natural rubber (NR) nanocomposites. The nanocomposites were prepared by using a combination of melt mixing and latex compounding method. Five different samples with different filler loading namely PAL2 (2 phr), PAL4 (4phr), PAL6 (6phr), PAL8 (8phr) and PAL10 (10 phr) were prepared in this work. All the samples were subjected to curing and tensile test. All the results were compared with pure gum of natural rubber. The curing characteristics of PAL/NR nanocomposites such as minimum and maximum torque were higher at optimum filler loading, PAL4. It means that the optimum filler loading would produce higher rigidity of the sample. Thus, PAL4 had higher stiffness compared to other filler loading. The scorch time and cure time of the sample that had undergone melt mixing and latex compounding method were higher compared to NR. The increase in both scorch time and cure time revealed that the presence of PAL could increase the curing process of the nanocomposites. Furthermore, PAL4 showed 18% increment in tensile strength. These results showed the optimum filler loading can increase the compatibility between PAL and NR. The size and shape of the PAL and the combination of melt mixing and latex compounding method might also contribute to this improvement. The morphology characteristics of all PAL/NR nanocomposites sample showed thicker tear line and rougher surface compared to control sample, NR. This might due to the homogenous dispersion of PAL which contains optimum filler loading. Thus, 4phr of palygorskite loading found to be the optimum filler loading with a combination of melt mixing and latex compounding methods.

Tensile Behavior of SiCNP and MWCNTs Filled Toughened Epoxy Nanocomposites: A Comparative Study

This study is conducted to evaluate the tensile properties of silicon carbide nanoparticles (SiCNP) and multiwalled carbon nanotubes (MWCNTs) filled toughened epoxy composites as a function of filler loading. The nanocomposites with different weight percentage of SiCNP and MWCNTs loading were fabricated by mechanical blending operation assisted with an ultrasonic cavitation technique. The loadings utilized were 0, 2, 4, and 6% of total composites weight. The result shows that the optimum filler loading of both systems were obtainable at 4% of SiCNP and MWCNTs of loadings. Composite with SiCNP filler achieved the highest value of tensile strength and Young's modulus at about 11% and 4%, respectively as compared to unfilled system. The enhancement pattern in MWCNTs nanocomposite systems were not significant as compared than SiCNP composite. The tensile strength and Young's modulus of MWCNTs composite were increased at only about 7% and 2%, respectively compared than unfilled system. The strain at break attribute for both filler system had shown reduction pattern at higher loading started from 2% loading and onwards. The variation in tensile properties were further supported by the tensile fracture morphologies and clearly shown that the filler-matrix plated an important role in affecting the tensile behavior of nanocomposite produced.

PENGARUH SUHU VULKANISASI DAN KOMPOSISI BENTONITE CLAY YANG DIMODIFIKASI DENGAN ALKANOLAMIDA DARI BAHAN BAKU RBDPKO PADA PRODUK LATEKS KARET ALAM

The is research aims to determine the effect of vulcanization temperature and composition of bentonite clay as good filler on mechanical properties of natural rubber latex product. In this study, we use bentonite clay as filler and alkanolamide as compatibilizer. The material used in this study are high ammonia latex 60%, curative agents such as sulfur, ZnO, ZDEC, AO, KOH, bentonite clay and alkanolamide. Alkanolamide is synthesized from amidation reaction between Refined Bleached Deodorized Palm Kernel Oil and diethanolamine. The methodology includes pre-vulcanizing natural rubber latex with certain formulation, then vulcanized using dipping method. The variable used in this study is filler loading, from 5, 10, 15, 20, and 25 gram, and vulcanization time 10 minutes. The products were then tested in order to observe its mechanical properties, FTIR characterization, SEM characterization and crosslink density. The results show that the synthesized alkanolamide possess the functional group desired. Alkanolamide modified bentonite clay loading is capable of increasing crosslink density and mechanical properties of the products. Optimum filler loading is reported on 10 gram and optimum vulcanization at 120oC.

Investigation on the properties of rubber composites containing modified clay

Purpose – The purpose of this paper is to evaluate the efficiency of organobentonite (OB) as reinforcing filler in acrylonitrile-butadiene rubber (NBR). The composites were prepared using different loadings of OB and studying in details their properties. A series of OB was modified using surfactant N-cetyl-N, N, N-trimethyl ammonium bromide (CTAB) with concentrations 0.5, 1 and 2 cation exchange capacity (CEC) of bentonite. Design/methodology/approach – The different bentonites were characterized using different analytical and spectro-photometric techniques, such as infra red, X-ray diffraction, thermogravimetric analysis and scanning electron microscopy, while rubber vulcanizate rheological, morphological, swelling and thermal properties were examined using different standard instrumental testing and methods. Findings – The study revealed that the modification of bentonite using CTAB showed significant enhancement on NBR properties, and the optimum filler loading was 12 phr for both 0.5CEC OB and 2CEC OB. These modified bentonites improved reinforcing properties to NBR vulcanizates. Also, results showed that composites exhibited remarkable improvements in tensile strength, elongation at break and hardness in the presence of modified bentonite and also an increase in thermal stability. Research limitations/implications – Na-B cannot be applied in rubber matrix without modification because it is incompatible with it. Practical implications – The modified bentonite is considered as efficient reinforcing filler which can replace other fillers because it has lower surface energy and improved intercalating behaviour in rubber matrix. Originality/value – These papered bentonites are cheap with relatively high purity, which make rubber/clay composites emerge as new class of material and can be used in different fields other than rubber.

The dielectric and thermal properties of Mn-doped (1 − x) ZrTi2O6–xZnNb2O6 filled PTFE composites

High dielectric constant and low loss (1 − x) ZrTi2O6–xZnNb2O6 ceramic fillers have been prepared by the conventional solid-state reaction technique. Ceramic filled polytetrafluoroethylene (PTFE) microwave composite substrates were fabricated through the hot-pressing process. The microwave dielectric properties of (1 − x) ZrTi2O6–xZnNb2O6/PTFE composites were measured using stripline resonator method. The relative dielectric constant (e r) and loss tangent (tan δ) of the composites increase with an increase of x in the (1 − x) ZrTi2O6–xZnNb2O6 ceramic at an optimum filler loading of 46vol%. As the x in the (1 − x) ZrTi2O6–xZnNb2O6 ceramic increase, the coefficient of thermal expansion and temperature coefficient of dielectric constant decrease. 0.55ZrTi2O6–0.45ZnNb2O6 filled PTFE composite exhibits a dielectric constant of 7.32 with a loss tangent of 0.0015 (10 GHz) and a temperature coefficient of dielectric constant of −84 ppm/oC at an optimum filler loading of 46 vol%.

Effect of silane coupling agent on the curing, tensile, thermal, and swelling properties of ethylene‐propylene‐diene monomer rubber (EPDM)/mica composites

The influence of silane (bis[3‐triethoxysilylpropyl] tetrasulfide) coupling agent on the properties of ethylene‐propylene‐diene monomer rubber (EPDM)/mica composites was studied. Both EPDM/mica composites with silane and those without silane were compounded by using a two‐roll mill at various filler loadings (i.e., 100/0, 100/10, 100/30, 100/50, 100/70). The tensile and thermal properties as well as the fracture surfaces of the composites were investigated by using an Instron Universal Testing Machine, a thermal gravimetric analyzer, and a field emission scanning electron microscope. The results indicated that the optimum cure time (t90) and scorch time (ts2) values were shorter, whereas the maximum torque (MH) value was slightly higher, for EPDM/mica composites with silane compared to those without silane. The tensile properties, modulus at 100% elongation, and modulus at 300% elongation increased for the composites made with silane, and the optimum filler loading for those properties was 50 parts by weight per hundred parts of rubber. In addition, thermal stability and swelling ratio for both composites improved with increased filler loading. However, the composites with silane showed better thermal stability and swelling ratio because of stronger linkage at the rubber‐filler boundary, which promoted filler dispersion. J. VINYL ADDIT. TECHNOL., 20:116–121, 2014. © 2014 Society of Plastics Engineers

ZrTi2O6 filled PTFE composites for microwave substrate applications

A new kind of ZrTi2O6 filled polytetrafluoroethylene (PTFE) microwave composite substrates was fabricated through the hot-pressing process. The microwave dielectric properties of ZrTi2O6/PTFE composites were measured using stripline resonator method. The relative dielectric constant (er) and loss tangent (tanδ) of the composites increase with an increase of the volume fraction of ZrTi2O6 ceramic (0–46 vol%). The experimental dielectric constants of the composites match well with theoretically predicted values by Lichtenecker mixing rule. As the volume fraction of ZrTi2O6 ceramic increases, the thermal expansion coefficient and the temperature coefficient of dielectric constant decrease. The ZrTi2O6 filled PTFE composite exhibits a dielectric constant of 7.42 with a loss tangent of 0.0022 (10 GHz) at an optimum filler loading of 46 vol%.

Effect of Space Charge Density and High Voltage Breakdown of Surface Modified Alumina Reinforced Epoxy Composites

The incorporation of 90 nm alumina particles into an epoxy matrix to form a composite microstructure is described in present study. It is shown that the use of ultrafine particles results in a substantial change in the behavior of the composite, which can be traced to the mitigation of internal charges when a comparison is made with conventional <TEX>$Al_2O_3$</TEX> fillers. A variety of diagnostic techniques have been used to augment pulsed electro-acoustic space charge measurement to provide a basis for understanding the underlying physics of the phenomenon. It would appear that, when the size of the inclusions becomes small enough, they act cooperatively with the host structure and cease to exhibit interfacial properties. It is postulated that the <TEX>$Al_2O_3$</TEX> particles are surrounded by high charge concentrations. Since <TEX>$Al_2O_3$</TEX> particles have very high specific areas, these regions allow limited charge percolation through <TEX>$Al_2O_3$</TEX> filled dielectrics. The practical consequences of this have also been explored in terms of the electric strength exhibited. It would appear that there was a window in which real advantages accumulated from the nano-formulated material. An optimum filler loading of about 0.5 wt.% was indicated.

Comparative study of micro- and nano-ZnO reinforced UHMWPE composites under dry sliding wear

This is a comparative study between ultra-high molecular weight polyethylene (UHMWPE) reinforced with micro-zinc oxide (ZnO) and nano-ZnO under different filler loads. These composites were subjected to dry sliding wear test under abrasive conditions. The micro- and nano-ZnO/UHMWPE composites were prepared by using a hot compression mould. The wear and friction behaviours were monitored using a pin-on-disc (POD) test rig. The pin-shaped samples were slid against 400 grit SiC abrasive papers, which were pasted, on the stainless steel disc under dry sliding conditions. The worn surfaces and transfer film formed were observed under the scanning electron microscope (SEM). Experimental results showed that UHMWPE reinforced with micro- and nano-ZnO would improve the wear behaviour. The average coefficient of friction (COF) for both micro- and nano-ZnO/UHMWPE composites were comparable to pure UHMWPE. The weight loss due to wear for nano-ZnO/UHMWPE composites are lower compared to micro-ZnO/UHMWPE and pure UHMWPE. The optimum filler loading of nano-ZnO/UHMWPE composites is found to be at 10wt%. The worn surface of ZnO/UHMWPE composites shows the wear mechanisms of abrasive and adhesive wear. Upon reinforcement with micro- and nano-ZnO, the abrasive and adhesive wear of worn surfaces transited from rough to smooth.

Effect of Silane Coupling Agent on the Curing, Tensile, Thermal, and Swelling Properties of EPDM/Mica Composites

In this work, the influence of silane (bis (3-triethoxysilylpropyl) tetrasulfide) or Si69 coupling agent on properties of EPDM/mica composites was studied. Both EPDM/mica composites with silane and without silane were compounded using two roll mill at various filler loading (i.e., 100/0, 100/10, 100/30, 100/50, 100/70). The tensile and thermal properties as well as fracture surfaces of composites were tested using Instron Universal Testing Machine, Thermal Gravimetric Analysis (TGA) and Emission Scanning Electron Microscope (SEM). The results indicated that the optimum cure (t90), scorch time (ts2) value was lower, while maximum torque (MH) value slightly higher for EPDM/mica composites with silane compared to EPDM/mica composites without silane. The tensile properties, M100 and M300 value increased for EPDM/mica composites in the presence of silane and the optimum filler loading for those properties occurred at 50 phr. In addition, thermal stability and swelling ratio for both composites improved with increasing filler loading. However, EPDM/mica composites with silane show better thermal stability and swelling ratio due to stronger linkage taking place at the rubberfiller boundary and it promotes filler dis-agglomeration.

Effects of different additions of sago starch filler on physical and biodegradation properties of pre-vulcanized NR latex composites

This paper presents results on the physical and biodegradation properties of pre-vulcanized natural rubber (NR) latex composites with sago starch as protein enhancer. Sago starch fillers are added into NR latex via Methods A (prior pre-vulcanization) and B (after pre-vulcanization) at 80°C. For the biodegradation process, composites are buried in soil and brought out on a weekly basis to investigate their mechanical and morphological properties. Results show that optimum filler loading are achieved at 10phr with optimum tensile properties. As the biodegradation periods elapse, the mechanical properties for both composites decrease, which indicates the occurrence of biodegradation process. Based on scanning electron microscope images, Method A shows better filler–rubber interaction system from the severed sago starch granular structure, whereas Method B gives better mechanical properties as evaluated from tensile properties.

Effect of gamma‐irradiation on the physicomechanical properties of synthetic rubber–based silica composites

AbstractRice husk ash (RHA) and silica‐filled nitrile rubber (NBR) composites were prepared using a laboratory‐size two‐roll mill. The mechanical properties and water absorption were studied before and after being exposed to gamma irradiation from 25 to 200 kGy. The tensile strength increased with RHA up to an optimum filler loading (20 phr) and (30 phr) for a silica‐filled NBR composite. The tensile strength for the irradiated composite filled with 30 phr silica increases with an increase in irradiation doses up to 100 kGy. The presence of silica filler phase that has a higher electron density than the polymer matrix will likely result in an increase in cross‐linking or scissioning and better dispersion in the matrix. Water absorption studies indicate that the irradiated NBR composite filled with silica has lower water absorption rather than the composite filled with RHA. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 30: 301–311, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20225

The Properties of Polymethyl Methacrylate (PMMA) Bone Cement Filled with Titania and Hydroxyapatite Fillers

Commercial acrylic bone cement was modified by incorporating different filler loadings of bioactive hydroxyapatite and titania nanopowders. The effects of nanofiller loading on the mechanical and thermal properties were evaluated. The peak temperature during the polymerization of bone cement was observed to decrease with increasing filler loading. In addition, the flexural strength decreased and morphological studies of the fracture surfaces revealed an increase in porosity with the increase in filler loading. Silanation was conducted on the optimum filler loading, and the influence of silanation on the mechanical properties of bone cement was assessed.

Ba(Mg 1/3Ta 2/3)O 3 filled PTFE composites for microwave substrate applications

Phase pure Ba(Mg 1/3Ta 2/3)O 3 (BMT) ceramic filler has been prepared through solid-state ceramic route and characterized using XRD. Planar BMT filled PTFE composites were fabricated through SMECH process comprising of Sigma Mixing, Extrusion, Calendering followed by Hot pressing. Morphology and filler distribution of the composites were studied using Scanning Electron Microscopic technique. The microwave dielectric properties of the composites at X-band were measured using waveguide cavity perturbation technique. BMT filled PTFE composite exhibits a dielectric constant of 6.7 with loss tangent 0.003 at optimum filler loading. Dielectric constant of the composites shows better matching with the theoretically predicted values using Litchnecker model. The moisture absorption characteristics of the samples were ascertained as per IPC-TM-650 2.6.2.1. The loss tangent of the PTFE/BMT composites was improved to 0.0018 while incorporating long range ordered BMT fillers.