Properties of Halloysite Nanotube (HNT) Filled SMR L and ENR 50 Nanocomposites

Various HNTs loading filled SMR L and ENR 50 were prepared. Addition of HNTs caused increments in scorch time, cure time, tensile modulus, and thermal stability of nanocomposites. Optimum tensile strength of nanocomposites was achieved at 20 phr loading. Elongation at break, swelling percentage, and fatigue life decreased with increasing HNTs loading. ENR 50 nanocomposites show shorter scorch time, longer cure time, and lower curing rate index than SMR L nanocomposites. ENR 50 nanocomposites also show higher tensile modulus and thermal stability than SMR L nanocomposites. SEM images show that HNTs can be dispersed more uniformly at lower filler loading.     

The Effect of Filler Loading and Epoxidation on Paper-Sludge-Filled Natural Rubber Composites

The effect of filler loading and epoxidation on curing characteristics, dynamic properties, tensile properties, morphology, and rubber-filler interactions of paper-sludge-filled natural rubber compounds have been studied. Two different types of natural rubber, SMR L and ENR 50, having 0% and 50% of epoxidation and conventional vulcanization were used. Paper sludge was used as a filler and the loading range was from 0 to 40 phr. Compounding was carried out using a laboratory-sized two-roll mill. The scorch time for both rubber compounds decreased with filler loading. The cure time was found to decrease with increasing filler content for SMR L vulcanizates, whereas for ENR 50, the cure time seemed to be independent of the filler loading. Dynamic properties, i.e., maximum elastic torque, viscous torque, and tan delta, increase with filler loading in both grades of natural rubber. Results also indicate that both rubbers show increment in tensile modulus but inverse trend for elongation at break and tensile strength. However, for a fixed filler loading, ENR 50 compounds consistently exhibit higher maximum torque, modulus at 100% elongation, and modulus at 300% elongation, but lower elongation at break than SMR L compounds. In the case of tensile strength, ENR 50 possesses higher tensile strength than SMR L at 10 to 20 phr, but the difference is quite small at 30 and 40 phr. These findings might be associated with better rubber-filler interaction between the polar hydroxyl group of cellulose fiber and the epoxy group of ENR 50.     

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.     

Curing Characteristics,Mechanical, Thermal,and Morphological Properties of Halloysite Nanotubes (HNTs)-Filled Natural Rubber Nanocomposites

Halloysite nanotubes (HNTs)-filled natural rubber (NR) nanocomposites with various filler loading were prepared by using a two-roll mill. The addition of HNTs increased the scorch time, cure time and maximum torque but reduced curing rate index. The tensile strength increased up to 20 phr of HNTs and then decreased. When HNTs loading increased, the elongations of break, swelling percentage and fatigue life were decreased while modulus at 100% and 300% elongation and thermal properties showed inversely. The dispersion of HNTs inside the NR matrix is shown from SEM images.     

Curing Characteristics,Fatigue and Hysteresis Behaviour of Feldspar Filled Natural Rubber Vulcanizates

Curing characteristics, fatigue, and hysteresis behaviour of feldspar filled SMR L vulcanizates and feldspar filled ENR 50 vulcanizates were studied. Two different types of natural rubber, SMR L and ENR 50 having 0 and 50 mol% of epoxide groups were used. The feldspar filled natural rubber vulcanizates were compared at similar filler loading which were used at 0, 10, 20, and 30 phr of filler loading. The curing characteristics such as scorch time (t ₂) and cure time (t ₉₀) slightly increased with increasing feldspar loading for both rubber vulcanizates. Besides t ₂ and t ₉₀, maximum torque (M _HR) significantly increased for both rubbers with increasing feldspar loading. The fatigue test showed that fatigue life decreased with increasing extension ratio, strain energy and filler loading. As the filler loading increased, the poor wetting of the feldspar by the rubber matrix gave rise to poor interfacial adhesion between filler and rubber matrix. Results also indicate that the vulcanizates with the highest feldspar loading exhibited the highest hysteresis. The feldspar filled SMR L vulcanizates showed higher fatigue life and lower hysteresis compare to feldspar filled ENR 50 vulcanizates.     

The Properties of Acrylonitrile-Butadiene Rubber (NBR) Composite with Halloysite Nanotubes (HNTs) and Silica or Carbon Black

The properties of acrylonitrile-butadiene rubber (NBR) composites were studied at five different compositions of NBR/HNTs/Silica or NBR/HNTs/CB (i.e., 100/5/0, 100/4/1, 100/3/2, 100/2/3, 100/0/5 parts per hundred rubber (phr)). The tensile strength and modulus (M100) of both composites decreased, whereas elongation at break increased and maximum torque with increasing the silica or carbon black content. However, both composites show opposite trends for cure time and scorch time, where NBR/HNTs/Silica composite exhibited an increasing trend, while NBR/HNTs/CB composite shows the decreasing trend. The rubber-filler interaction studies showed that carbon black is a more reinforcing filler than silica.     

Curing Characteristics,Mechanical and Morphological Properties of Kenaf Fibre/Halloysite Nanotubes Hybrid-Filled Natural Rubber Compounds

Natural rubber compounds were prepared with different kenaf/HNT ratio loading i.e., 30/0, 20/10, 15/15, 10/20, 0/30 (phr/phr). The compounds were cured at 150°C according to its t₉₀. Curing characteristic, tensile properties, fatigue, rubber-filler interaction and morphological properties of the compounds were tested. Curing characteristics show that scorch time and cure time increased with increasing of HNT ratio loading while minimum and maximum torque decreased. When HNT ratio loading was increased, tensile strength and elongation at break and fatigue life increased while tensile modulus decreased. Swelling measurement and morphological study showed that better rubber-filler interaction was obtained with higher HNT ratio loading.     

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.     

Preparation of Cu(II)-Immobilized Chitosan (CIC) and Preliminary Urea Uptake Study

The effect of filler loading and size on commercially available silica (Vulcasil C) and value added silica (ultrafine) as filler in SMR L grade natural rubber were studied. Vulcasil C with particle size ranged from 10 µm–20 µm whilst ultrafine (1 µm–3 µm) was loaded in SMR L compound at 4 different loadings. The curing characteristics, tensile properties and swelling behavior were studied. At similar filler loading, ultrafine-filled vulcanizates exhibited shorter scorch time and cure time. It also shows higher tensile strength and elongation at break up to 20 phr filler loading and exhibit lower swelling ratio compared to Vulcasil C-filled vulcanizates.     

The Effect of Ethylene Diamine Dilaurate and Silane Coupling Agent on Cure Characteristics,Mechanical, and Thermal Properties of Silica-Filled Natural Rubber Composites

The influence of a new coupling agent, ethylene diamine dilaurate (EDD) and a commercial silane coupling agent, (Si-69) on the cure characteristics, mechanical and morphological properties of silica-filled natural rubber (NR) composites was studied. The results show that scorch time and cure time decreased with an increase in both coupling agents' content, but maximum and minimum torques exhibit the opposite trend. The mechanical properties such as tensile strength and tensile modulus, M100 and M300, increased with increasing both coupling agents' content but at a similar coupling agent content, silica-filled natural rubber composites with Si-69 exhibit better tensile strength (more than 2 phr) and tensile modulus than does EDD. Elongation at break (Eb) of silica-filled natural rubber increased with increasing EDD content but Si-69 exhibits the opposite trend. Scanning electron microscopy (SEM) study of tensile fracture surfaces shows the better tensile strength of silica-filled natural rubber composites with Si-69 and EDD over control composites (without EDD or Si-69). Thermogravimetric analysis (TGA) results indicate that silica-filled NR composites with EDD have higher thermal stability than Si-69. Fourier transform infrared spectra (FTIR) provided an evidence of interaction between EDD and Si-69 with silica in NR composites.     

TENSILE PROPERTY OF EPOXIDIZED NATURAL RUBBER/NATURAL RUBBER BLENDS

The tensile strength and elongation at break of epoxidized natural rubber (ENR) blended with natural rubber (NR) was studied. ENR 25, ENR 50, and one grade of natural rubber (SMR L) were used as the elastomers. The composition of ENR was varied from 0% to 100% rubber. The accelerated sulfur vulcanization system was used throughout the investigation. The tensile property of unaged and aged samples was determined by using the Monsanto tensometer (T10) operating at 50 cm/min. Results show that the tensile strength and elongation at break passes through a maximum at 50% ENR for both ENR25/SMR L and ENR50/SMR L blends. This positive deviation from ideality is attributed to the mutual reinforcement of ENR and NR in the blends as a result of strain-induced crystallization. This synergistic effect is more pronounced in the case of ENR 25 due to the higher crystallinity and availability of more double bonds, which is more compatible to NR compared to ENR 50/NR blends. For the aged samples, a drop in the tensile property associated to the breakdown of the polysulfidic cross-link during aging is observed. A systematic study of the effect of sulfur concentration on the percentage retention of tensile property of the ENR blends after aging reveals that percentage retention decreases with increasing sulfur loading, which, in turn, enhances the formation of the polysulfidic cross-link; thus, more breakdown is observed in the rubber vulcanizate.     

Maleated Natural Rubber as a Coupling Agent for Recycled High Density Polyethylene/Natural Rubber/Kenaf Powder Biocomposites

Kenaf powder (KP) was incorporated into recycled high density polyethylene (rHDPE)/natural rubber (NR) blend using an internal mixer at 165°C and rotor speed of 50 rpm. The tensile strength and elongation at break of the composites decreased, while the tensile modulus increased with increasing filler loading. The water absorption was found to increase as the filler content increased. The maleic anhydride grafted natural rubber was prepared and used to enhance the composites performance. The addition of MANR as a coupling agent improved the tensile properties of rHDPE/NR/KP biocomposites. The water absorption was also reduced with the addition of MANR.     

The Effect of Carbon Black/Multiwall Carbon Nanotube Hybrid Fillers on the Properties of Natural Rubber Nanocomposites

The properties of hybrid multiwall carbon nanotube (MWCNT) and carbon black (CB) in natural rubber nanocomposites were studied. The results show that the scorch and cure time decreased as the MWCNT loading increased in CB/MWCNT hybrid loading ratio but for the maximum torque, the result shown otherwise. As the MWCNT loading increased in CB/MWCNT hybrid loading ratio, the tensile strength, elongation at break and fatigue life are decrease, however the tensile modulus and rubber filler-interaction (Q_f/Q_g) value increased. The SEM results show a dispersion of CB and MWCNT in natural rubber matrix. Furthermore, the thermal stability for the hybrid nanocomposites is enhanced.     

Enhancement of PVC/ENR blend properties by poly(methyl acrylate) grafted oil palm empty fruit bunch fiber

Effect of oil palm empty fruit bunch (OPEFB) fiber and poly(methyl acrylate) grafted OPEFB on several mechanical properties of poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blends using HAKEE Rheomixer at the rotor speed of 50 rpm, mixing temperature 150°C, and mixing period of 20 min. The fiber loadings were varied from 0 to 30% and the effect of fiber content in the composites on their ultimate tensile strength (UTS), Young's modulus, elongation at break, flexural modulus, hardness, and impact strength were determined. An increasing trend was observed in the Young's modulus, flexural modulus, and hardness with the addition of grafted and ungrafted fiber to the PVC/ENR blends. However the impact strength, UTS, and elongation at break of the composites were found to decrease with the increase in fiber loading. An increase in elongation at break and UTS and decrease in the flexural and Young's modulus was observed with the addition of PMA‐g‐OPEFB fiber compared to ungrafted fiber. This observation indicates that grafting of PMA onto OPEFB impart some flexibility to the blend. The morphology of cryogenically fractured and tensile fracture surfaces of the composites, examined by a scanning electron microscope shows that the adhesion between the fiber and the matrix is improved upon grafting of the OPEFB fiber. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Tensile properties,swelling, and water absorption behavior of rice‐husk‐powder‐filled polypropylene/(recycled acrylonitrile‐butadiene rubber) composites

The effect of rice husk powder (RHP) on the tensile properties, swelling, water absorption, and morphology of polypropylene (PP)/[recycled acrylonitrile‐butadiene rubber (NBRr)]/RHP composites was studied. Composites containing 0 to 30 parts of RHP per hundred parts of resin were prepared by using a Haake Rheomix Polydrive R 600/610 mixer at 180°C with a rotor speed of 50 rpm. Results indicated that the tensile strength and elongation at break decreased but that the tensile modulus increased with increasing amounts of RHP. Swelling of the PP/NBRr/RHP composites in oil and toluene increased with increasing RHP contents, and the composites exhibited a non‐Fickian diffusion with a two stage absorption mechanism. Micrographs acquired by SEM revealed an increasing number of voids and micro‐holes on the tensile‐fractured surfaces of the composites with increasing amounts of RHP. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

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     

Thermoplastic Elastomer Composites of Palm Ash-Filled Ethylene Vinyl Acetate/Natural Rubber Blends: Effects of Palm Ash Loading and Size

Thermoplastic elastomer composites of ethylene vinyl acetate (EVA)/natural rubber (NR) blends filled with palm ash were prepared by melt-mixing using a Haake Rheomix Polydrive R600/610 at 120°C with rotor speed of 50 rpm for 10 minutes. Increase in palm ash loading in composites resulted in increase the value of stabilization toque, Young's modulus and swelling resistance of the composites, but decreased the tensile strength and elongation at break. Scanning electron microscope micrographs revealed that higher filler loading resulted in agglomeration of palm ash in the composites. When smaller particle size of palm ash was used, further improvement in tensile strength, elongation at break, swelling resistance and stabilization torque value were observed.     

Effect of filler loading on cure time and swelling behaviour of SMR L/ENR 25 and SMR L/SBR blends

The effect of filler loading on the cure time (t₉₀) and swelling behaviour of SMR L/ENR 25 and SMR L/SBR blends has been studied. Carbon black (N330), silica (Vulcasil C) and calcium carbonate were used as fillers and the loading range was from 0 to 40 phr. Results show that for SMR L/ENR 25 blends the cure time decreases with increasing carbon black loading, whereas silica shows an increasing trend, and calcium carbonate does not show significant changes. For SMR L/SBR blends, the cure time of carbon black, silica and calcium carbonate generally decreases with increasing filler loading. The percentage swelling in toluene and ASTM oil no 3 decreases for both blends with increasing filler loading, with calcium carbonate giving the highest value, followed by silica‐ and carbon black‐filled blends. At a fixed filler loading, SMR L/ENR 25 blend shows a lower percentage swelling than SMR L/SBR blends. © 2003 Society of Chemical Industry     

多元醇对氯醚橡胶力学性能的影响研究

研究了3种多元醇--丙三醇(Gly)、三羟甲基丙烷(TMP)和季戊四醇(PER)对共聚型氯醚橡胶(ECO)硫化特性、交联密度、力学性能的影响。结果表明,添加丙三醇的胶料的焦烧时间与正硫化时间最短,交联密度最大,力学性能最好。丙三醇用量为2 phr、炭黑用量为40 phr时胶料的拉伸强度达14.1 MPa,扯断伸长率达685%,300%定伸应力达6.8 MPa,硬度为63。     

The Effect of Electron Beam (EB) Irradiation in Presence of TMPTA on Cure Characteristics and Mechanical Properties of Styrene Butadiene Rubber/Recycled Acrylonitrile-Butadiene Rubber (SBR/NBRr) Blends

The effect of electron beam (EB) irradiation on the cure characteristics and mechanical properties of unirradiated and irradiated SBR/NBRr blends were investigated. The SBR/NBRr blends were prepared at 95/5, 85/15, 75/25, 65/35, and 50/50 blend ratio with and without the presence of a polyfunctional monomer, trimethylolpropane triacrylate (TMPTA). Results indicated that the scorch time t₂, cure time t₉₀ and minimum torque (M_L) of irradiated SBR/NBRr blend decreased, but the maximum torque (M_H) particularly at 35 and 50 phr of NBRr (recycled NBR) increased with the presence of TMPTA. The stress at 100% elongation (M100), hardness, cross-linking density and tensile strength (particularly after 15 phr of NBRr content) of irradiated SBR/NBRr blends increased after irradiation but the elongation at break (EB) and resilience decreased. The irradiated SBR/NBRr blends showed lower thermal stability than non-irradiated blends. Scanning electron microscopy proved the enhancement in tensile strength when more NBRr were added in SBR matrix where the irradiated surfaces demonstrate more irregularity with increasing crack branching (fracture planes are located at different heights) due to the increased of cross-linked density.