Sepiolite hybridized commercial fillers,and their effects on curing process,mechanical properties,thermal stability,and flammability of ethylene propylene diene monomer rubber composites

Ethylene propylene diene monomer rubber (EPDM)-based composites containing sepiolite (sep) hybridized with calcium carbonate (CaCO₃), silica (Sil) or carbon black (CB) were prepared on a two-roll mill. The influence of fillers’ contents on the curing, mechanical, thermal and flammability of the composites was investigated. In comparison with EPDM/sep at 30 parts per hundred rubbers (phr) as a control composite, EPDM/sep/CB composites exhibited an outstanding improvement in tensile strength followed by EPDM/sep/Sil and EPDM/sep/CaCO₃ composites. EPDM/sep/CB displayed the highest thermal stability and also improved flammability resistance. In addition, a higher amount of carbon black gave higher tensile strength. The results were influenced by the ability of CB to disperse well and form protective layers acting as mass transport barriers in the matrix. The field emission scanning electron microscopy analyses proved better dispersion of CB in the matrix. The presence of protective layers on the surface of samples consequently improved the thermal properties of the EPDM composites. The mechanism of formation of char protective layer in hybrid EPDM composites was also investigated based on morphological observations of char residues. According to this work, Sil and CB were able to hybrid with sep, while sep could be a potential substitution of CaCO₃ in the EPDM composites.     

Effect of different nanoparticles on thermal,mechanical and dynamic mechanical properties of hydrogenated nitrile butadiene rubber nanocomposites

Organically modified and unmodified montmorillonite clays (Cloisite NA, Cloisite 30B and Cloisite 15A), sepiolite (Pangel B20) and nanosilica (Aerosil 300) were incorporated into hydrogenated nitrile rubber (HNBR) matrix by solution process in order to study the effect of these nanofillers on thermal, mechanical and dynamic mechanical properties of HNBR. It was found that on addition of only 4 phr of nanofiller to neat HNBR, the temperature at which maximum degradation took place (T_max) increased by 4 to 16°C, while the modulus at 100% elongation and the tensile strength were enhanced by almost 40–60% and 100–300% respectively, depending upon nature of the nanofiller. It was further observed that T_max was the highest in the case of nanosilica‐based nanocomposite with 4 phr of filler loading. The increment of storage modulus was highest for sepiolite‐HNBR and Cloisite 30B‐HNBR nanocomposites at 25°C, while the modulus at 100% elongation was found maximum for sepiolite‐HNBR nanocomposite at the same loading. A similar trend was observed in the case of another grade of HNBR having similar ACN content, but different diene level. The results were explained by x‐ray diffraction, transmission electron microscopy, and atomic force microscopy studies. The above results were further explained with the help of thermodynamics. Effect of different filler loadings (2, 4, 6, 8, and 16 phr) on the properties of HNBR nanocomposites was further investigated. Both thermal as well as mechanical properties were found to be highest at 8 phr of filler loading. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of gamma‐irradiation on the mechanical behavior of EPDM rubber‐recycled newsprint microfibers composites

Waste newsprint paper was collected from the local market and subjected to chemical pulping using 2 M NaOH. The fiber, after getting rid of water, was treated again using 2 M HCl solution for the same time period. The obtained newsprint microfibers (NPFs) were characterized by using scanning electron microscopy (SEM), X‐ray diffraction (XRD), and Fourier transform infrared spectra. Then the dried and grounded NPF batch was mixed with ethylene propylene diene monomer (EPDM) rubber using different concentrations ranged from 5 to 50 phr. The prepared composites were irradiated by using gamma rays at different doses from 20 to 100 kGy. The mechanical properties of prepared EPDM/NPFs composites such as tensile strength (Ts), elongation at break (E_b%), tensile modulus (M₁₀₀), toughness (T_t), and crosslink density (Cd) were measured as a function of fiber contents and irradiation dose. The results indicated that the tensile strength (Ts) increases with increasing microfibers contents up to 10 phr and irradiation dose up to 40 kGy, while E_b% decreases as the fibers content and irradiation dose increase. M₁₀₀ and Cd values increase with increasing fibers content up 50 phr fibers and irradiation dose up to 60 kGy. The results also concluded that the toughness values of EPDM/NPFs composites reach its maximum degree when using 10 phr NPFs concentration and 60 kGy irradiation dose. J. VINYL ADDIT. TECHNOL., 25:198–212, 2019. © 2018 Society of Plastics Engineers     

Curing Characteristics,Morphological, Tensile and Thermal Properties of Bentonite-Filled Ethylene-Propylene-Diene Monomer (EPDM) Composites

Bentonite (Bt) with irregular shape and surface morphology was used as a new type of filler in EPDM. EPDM/Bt composites were prepared using a laboratory size two-roll mill by adding 0 to 70 phr Bt. The effects of Bt loading on curing characteristics, morphology, tensile and thermal properties of EPDM/Bt composite were studied. Scorch and curing time were decreased with 0 to 30 phr loading and increased subsequently at 50 and 70 phr. Tensile strength and elongation at break (E_b) were increased with increasing Bt loading from 0 to 50 phr and decreased at 70 phr, whereas the tensile modulus (M100%) shows an increasing trend with increasing Bt loading. Thermogravimetric analysis shows the enhancements of thermal properties with increasing Bt loading. Morphological studies of tensile fracture surfaces of EPDM/Bt composite proves good interaction between Bt particles and EPDM at 50 phr and formation of Bt agglomerates at 70 phr.     

Preparation and characterization of hemp hurd powder filled SBR and EPDM elastomers

The effect of HP loading on the curing characteristics and mechanical properties of filled SBR and EPDM composites was investigated using bis-(3-triethoxysilylpropyl) tetrasulfide (Si69) as coupling agent. For all composites, 20 phr (part per one hundred parts of rubber) silica was used. The addition of HP enhances the vulcanization process of composites filled with silica. The hybrid reinforcement of HP and silica imparts good stiffness and toughness to filled rubber composites. An excess of HP will tend to form agglomerates in the rubber matrix, which adversely affects the silica-rubber matrix interfacial interaction, and consequently lowers the overall mechanical properties. The HP distribution and filler-rubber matrix interaction, which were analyzed by scanning electron microscopy and equilibrium swelling, explained well the changes in mechanical properties of composites filled with hybrid fillers. Dynamic mechanical analysis indicated that the composites exhibited higher Payne effect and storage modulus, and lower tanδ_max value with an increase of HP loading.     

Effects of curing systems and polysulfonamide pulp on the curing characteristics,mechanical properties,and swelling behavior of ethylene–propylene–diene elastomer composites

The effects of three curing systems and polysulfonamide (PSA) pulp on the curing characteristics, mechanical properties, and swelling behavior of ethylene–propylene–diene elastomer (EPDM) composites were investigated. The maximum torque value and the optimum curing time were highest for EPDM composites cured with a peroxide system, and they were closely followed by those cured with a sulfur system. In comparison with those cured with peroxide and phenolic resin systems, EPDM composites cured with the sulfur system showed higher mechanical properties and dimensional stability. With increasing PSA pulp content, the maximum torque value of the EPDM composites increased, whereas the optimum curing time of the composites decreased. The orientation percentage of the PSA pulp in the EPDM composites was maximum at 30 phr pulp, as determined from green strength measurements. In the longitudinal direction along which the pulp was oriented, the EPDM composites showed higher tensile strength as well as lower elongation and swelling ratios. Also, with increasing PSA pulp content, the tensile strength of the EPDM composites decreased up to 10 phr pulp and subsequently increased, whereas the elongation and swelling ratio of the EPDM composites decreased linearly. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Maleated polyethylene as a compatibilizing agent in cannabis indica stem’s flour-reinforced composite materials

Ethylene propylene diene terpolymer (EPDM) composites reinforced with wood flour of White Russian indica cannabis (ICF), a variety of marijuana obtained from government-licensed crops, were prepared. Wide particle size distribution range (136–1580 µm) of ICF was used. The wood flour was superficially treated with sodium hydroxide, and subsequently washed and dried. Composites with 30 and 60 parts of ICF by weight per hundred of rubber (phr) were prepared. Maleated polyethylene (MAPE) was used as a compatibilizer/coupling agent. The rubber compounds were mixed on a laboratory two-roll mill and cured composite sheets were obtained using compression molding technique. The effects of ICF and MAPE on the mechanical and physical properties of composites were analyzed. The addition of MAPE had positive effects on tensile strength, abrasion resistance, tear strength and compression set. The compatibilizing agent also had a slight effect on the hardness. The Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) results confirmed that MAPE improved the interfacial adhesion between the ICF particle and EPDM matrix. ICF and MAPE slightly affected the crystallinity, characterized using X-ray diffraction microscopy, and curing behavior of the composites. Lightweight (ρ?=?0.92 g/cm³) composites were obtained with load levels up to 60 phr of ICF.     

Thermal properties and crystallization behaviors of polylactide/redwood flour or bamboo fiber composites

A series of polylactide/redwood flour (PLA/RWF) and polylactide/bamboo fiber (PLA/BF) composites were successfully prepared using a solution mixing procedure. Fourier transform infrared spectroscopy (FTIR) and wide-angle X-ray diffraction (XRD) were employed to characterize these composites. Thermal properties and crystallization behaviors of PLA composites were determined by their respective techniques of differential scanning calorimetry (DSC) and polarized optical microscopy (POM). With the increasing content of fibers, the glass transition temperature (T _g ), crystallization temperature (T _c ), and melting temperature (T _m ) of PLA/RWF composites decreased first and then increased, but T _g and T _m of PLA/BF composites increased first and decreased afterwards. It is suggested that fibers could improve the segmental mobility of PLA; meanwhile, the different morphologies, sizes, and densities of RWF and BF have different effects on thermal properties of composites. Under the increasing content of RWF, the crystallization rate of the composite increased first and decreased afterwards. When the content of RWF was 5%, the crystallization rate was at its maximum. It could be possible that the addition of fibers was able to nucleate PLA and increase the degree of crystallinity, but the excess content of fibers easily led to heterogeneous composites and subsequent poor crystallization behaviors. In a word, thermal properties and crystallization behaviors of PLA composites were regularly changing by increasing content of fibers.     

Optimization and effect of 3‐aminopropyltriethoxysilane content on the properties of bentonite‐filled ethylene propylene diene monomer composites

The effect of silane coupling agent, 3‐aminopropyltriethoxysilane (APTES) content on the curing, tensile, swelling, and morphological properties of bentonite (Bt)‐filled ethylene‐propylene‐diene monomer (EPDM) composite was studied. The EPDM composites containing constant Bt composition of 30 phr and various APTES content (0, 1, 3, and 5 phr) were prepared using a laboratory scale two‐roll mill. The result showed that the cure time (t₉₀) and scorch time (t_S2) were shortened, whilst, the cure rate index (CRI), the maximum (M_H) and minimum (M_L) torque increased with increasing APTES content. The experimental results revealed that the optimum APTES content that led to the highest tensile and swelling properties was 3 phr. The presence of APTES greatly improved the dispersion of Bt in EPDM matrix and enhanced the interfacial interaction between EPDM and Bt. Morphological study through scanning electron microscopy revealed the enhanced adhesion between EPDM and Bt in the presence of 3 phr APTES. POLYM. COMPOS., 33:1993–2000, 2012. © 2012 Society of Plastics Engineers     

Properties of Ferrite-Filled Natural Rubber Composites

Nickel zinc ferrite (Ni-ZnFe₂O₄)-filled natural rubber (NR) composite was prepared at various loading of ferrite. The tensile properties included in this study were tensile strength, tensile modulus and elongation at break. The tensile strength and elongation at break of the composites increased up to 40 parts per hundred rubber (phr) of ferrite and then decreased at higher loading whereas the tensile modulus was increased gradually with increasing of ferrite loading. Scanning electron microscopy (SEM) was used to determine the wettability of filler in rubber matrix. From the observation, the increase of filler loading reduced the wettability of the filler. Thermal stability of the composites was conducted by using a thermogravimetry analyser (TGA). The incorporation of ferrite in NR composites enhanced the thermal stability of NR composites. The swelling test results indicate that the swelling percentage of the composites decreased by increasing of ferrite loading. The initial permeability, μ_i and quality factor, Q of magnetic properties of NR composites achieved maximum value at 60 phr of ferrite loading for frequency range between 5000–40,000 kHz. The maximum impedance, Z _max of the NR composites was at the highest value at 80 phr ferrite loading for frequency range between 200–800 MHz.     

The partial replacement of silica or calcium carbonate by halloysite nanotubes as fillers in ethylene propylene diene monomer composites

The effect of partial replacement of silica or calcium carbonate (CaCO₃) by halloysite nanotubes (HNTs) on the curing behavior, tensile properties, dynamic mechanical properties, and morphological characteristics of ethylene propylene diene monomer (EPDM) composites was studied. Five different compositions of EPDM/Silica/HNT and EPDM/CaCO₃/HNT compounds (i.e. 100/30/0, 100/25/5, 100/15/15, 100/5/25, and 100/0/30 parts per hundred rubber (phr)) were prepared on a two‐roll mill. The results indicated that the replacement of CaCO₃ by HNTs increased the tensile strength, elongation at break (E_b), and tensile modulus of composites from 0 to 30 phr of HNTs whereas for silica, the maximum tensile strength and E_b occurred at 5 phr loading of HNTs with an enhanced stress at 300% elongation (M300). The curing results show that, with replacement of silica or CaCO₃ by HNTs, the cure time (t₉₀) and cure rate (CRI) were decreased and increased, respectively. Scanning electron microscopy investigation confirmed that co‐incorporation of 5 phr of HNTs with silica would improve the dispersion of silica and enhanced the interactions between fillers and EPDM matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Comparative behavior of in situ silica generation in saturated rubbers: EPDM and hydrogenated natural rubber

Role of carbon‐carbon double (C?C) bonds content and their position in ethylene‐propylene diene ter‐polymer (EPDM), hydrogenated natural rubber (HNR) and natural rubber (NR) on in situ silica formation using tetraethoxysilane (TEOS) as a silica precursor is comparatively investigated. Glass transition temperature (T_g ) reflecting rubber chain flexibility is found as an important factor for in situ silica generation via swelling method. Despite of similar solubility parameters, NR has higher TEOS‐swelling degree resulting in the higher in situ silica content (30.8 phr) than EPDM (3.50 phr) and HNR (10.4–17.6 phr) due to the higher T_g of EPDM and HNR providing the less chain flexibility to be swollen in TEOS solution. The morphological analysis implies that C?C bonds in saturated rubbers may be agglomeration sites for in situ silica particles. For practical applications, saturated rubbers containing in situ silica/NR vulcanizates showed the improvement of mechanical properties and resistance of thermal and ozone degradation. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44748.     

Structure and mechanical properties of nanodispersed fibrous silicate‐reinforced ethylene–propylene–diene monomer nanocomposites

In this study, ethylene–propylene–diene monomer (EPDM)/fibrillar silicate (FS) nanocomposites were successfully prepared by mechanically blending EPDM with FS, which was modified by silane coupling agent KH570 containing methacryloxy group. The effects of silane content and modified FS on the dispersion of FS and mechanical properties of the composites were investigated. The impact of water in FS on mechanical properties of the composites was also evaluated. The results showed that modified FS could be dissociated into nanofibers dispersing evenly in the EPDM matrix by increasing substantially the loading of silane through the mechanical blending. The optimum loading level of silane coupling agent was up to 24 phr/100 phr FS. Silane KH570 could improve the dispersion of FS and strengthen nanofibers–rubber interfacial adhesion even at the loading of as high as 50 phr FS, making FS to exhibit excellent reinforcement to EPDM. Too much FS could not be completely dissociated into nanofibers, slowing down further improvement. The EPDM/FS composites exhibited the similar stress–strain behavior and obvious mechanical anisotropy with short microfiber‐reinforced rubber composites. With the increase in silane coupling agent and modified FS, the number of nanofibers increased because of the exfoliation of FS microparticles; thus, the mechanical behaviors would become more obvious. It was suggested that the free water in FS should be removed before mechanically blending EPDM with FS because it obviously affected the tensile properties of the composites. Regardless of whether FS was dried or modified, the EPDM/FS composites changed little in tensile strength after soaked in hot water. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Improvement in thermal conductivity and mechanical properties of ethylene‐propylene–diene monomer rubber by expanded graphite

Thermally conductive fillers are usually employed in the preparation of rubber composites to enhance thermal conductivity. In this work, ethylene‐propylene‐diene monomer rubber (EPDM)/expanded graphite (EG) and EPDM/graphite composites with up to 100 phr filler loading were prepared. Compared to EPDM/graphite compounds with the same filler loading, stronger filler network was demonstrated for EPDM/EG compounds. Thermal conductivity and mechanical properties of EPDM/graphite and EPDM/EG composites were compared and systematically investigated as a function of the filler loading. The thermal conductivity of both EPDM/graphite and EPDM/EG composites increased with increasing volume fraction of fillers, and could be well fitted by Geometric Mean Model. The thermal conductivity as high as 0.910 W · m⁻¹ · K⁻¹ was achieved for the EPDM/EG composite with 25.8 vol% EG, which was ∼4.5 times that of unfilled EPDM. Compared to EPDM/graphite composites, EPDM/EG composites exhibited much more significant improvement in thermal conductivity and mechanical properties, which could be well correlated with the better filler‐matrix interfacial compatibility and denser structure in EPDM/EG composites, as revealed in the SEM images of tensile fracture surfaces. POLYM. COMPOS., 38:870–876, 2017. © 2015 Society of Plastics Engineers     

Natural graphite reinforced fluoroelastomer composites: Morphological,mechanical, thermal,dielectric, and solvent transport studies

Fluoroelastomer (FKM) composite embedded with natural graphite (NG) was prepared and its thermal, mechanical, dielectric, and solvent transport properties were explored as a function of NG loading. The morphology of the composites was done by AFM, SEM, and TEM analysis, and XRD provides the structural analysis. The composite with 20 phr of NG content showed the highest tensile properties and thermal stability and was supported by fracture surface SEM analysis. Enhancement in polymer-filler interaction in the composite was further confirmed by the increase in T_g value obtained from DSC analysis. The dielectric permittivity value showed tremendous increment by 30 phr of NG addition with decreased dielectric loss. The resistance to solvent uptake with increase in NG loading by the formation of tortuous pathway is also a clear evidence for the exfoliation of the graphite flakes in the FKM matrix. Better inclusion of NG in FKM matrix efficiently enhanced the thermal, mechanical, dielectric and the transport properties of the composites.     

海泡石对三元乙丙橡胶阻燃性能的影响

以三元乙丙橡胶(EPDM)为基体材料,考察了海泡石的用量对复合材料力学性能及阻燃性能的影响,并与填料白炭黑进行了对比.结果表明,随着海泡石用量的增加,EPDM复合材料的力学性能明显提高,但是不如白炭黑增强效果显著.随着海泡石用量的增加,EPDM复合材料的氧指数呈增加趋势,最大热释放速率及总热释放量都呈降低趋势.与白炭黑...     

Study on Tensile,Electrical, and Thermal Properties of Aluminium Particle Filled Natural Rubber (NR) and Ethylene-Propylene-Diene Terpolymer (EPDM) Composites

Comparative studies on the effect of aluminium particles in natural rubber (NR) and ethylene-propylene-diene terpolymer (EPDM) were conducted. The incorporation of aluminium particles in NR or EPDM composites increased the cure time, t ₉₀, and scorch time, t _S2 . At a fixed filler loading, EPDM composites exhibited longer t ₉₀ and t _S2 than NR composites. The results also indicate that the maximum torque, M _H of aluminium filled NR and EPDM composites increase with increasing filler loading. For tensile properties, EPDM composites show lower tensile properties than NR composites. Thermogravimetric analysis (TGA) results show that aluminium filled EPDM composites have better thermal stability than aluminium filled NR composites.

The results for electrical properties indicate that the electrical properties of aluminium filled NR and EPDM composites increase with increase in filler loading.     

Nano-BN/Nano-TiO2 and micro Mg(OH)2 loaded hybrid ethylene propylene diene monomer elastomer composites for outdoor high-voltage insulation application

This work deals with the synthesis, characterization of hybrid ethylene propylene diene monomer (EPDM) composites loaded with nano-boron nitride (nano-BN)/nano-titanium dioxide (nano-TiO₂) and micro Mg(OH)₂ particles for its suitability towards high-voltage insulation application. The elastomer samples were prepared by carefully dispersing the micro and nano fillers during the mastication process of EPDM polymer using a two roll mill, followed by vulcanization. The samples were characterized for mechanical, morphological, thermal, and electrical insulation properties. The highest tensile strength among the composite samples was noted for 1 phr nanoparticles loaded samples. Fourier Transform Infrared (FTIR) results show no change in the chemical moiety upon addition of nano-BN/nano-TiO₂ in EPDM composites. Enhancement in hydrophobicity is observed for 3 phr nano-TiO₂ loaded composites, which shows a maximum static contact angle of 110°. Meanwhile remarkable enhancement in the thermal conductivity and volume resistance of the composites are contributed to the addition of nano-BN, thereby achieving maximum dielectric breakdown voltage (i.e., ~21 kV/mm for EMB3). Scanning electron microscope images and atomic force microscopy (AFM) topography highlight that low concentration (i.e., 1 phr) based composites have homogeneous dispersion in matrix and excessive nano filler addition deteriorates properties by forming filler aggregates and increasing surface roughness.     

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 (t_s2) values were shorter, whereas the maximum torque (M_H) 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     

Electrical and flammability properties of alumina trihydrate filled polypropylene/ethylene propylene diene monomer composites as insulators in cable applications

Polymeric insulators role in power systems and insulation is one of the most important subjects in high voltage applications. This study investigates the effect of alumina trihydrate (ATH) loading on electrical and flammability properties of polypropylene (PP)/ethylene propylene diene monomer (EPDM) blend. ATH fillers were incorporated into the matrix to improve the tracking and flammability resistance of the composites. PP/EPDM (60:40) was used as matrix and compounding of ATH filled PP/EPDM composites was done using a twin‐screw extruder. Electrical and flammability tests of composites were performed. The results show that flammability decreased with increasing ATH loading in PP/EPDM composites. The effects of electrical stresses are investigated by measuring the carbon tracking (CT) and leakage current (LC) on the surface of composites. The CT and LC of PP/EPDM/ATH composites were found to decrease with increasing ATH content; however calculating the normalized degradation index (NDI) illustrated that all the sample were in accepted range. Field emission scanning electron microscope was used to relate the electrical properties with the morphological analysis, which showed that addition of ATH prevents the degradation of the matrix. POLYM. ENG. SCI., 54:493–498, 2014. © 2013 Society of Plastics Engineers