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1.
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.  相似文献   

2.
The effects of palm oil fatty acid concentration (0, 1, 3, 5, 7 phr) and epoxidation on curing characteristics, reversion and fatigue life of carbon black filled natural rubber compounds have been studied. Three different types of natural rubber, SMR L, ENR 25 and ENR 50 having 0, 25 and 50 mol% of epoxidation and conventional sulphur vulcanization were used. The cure time t90, scorch time t2, MHRML (maximum torque − minimum torque) and fatigue life of all rubbers were found to increase with increasing palm oil fatty acid concentration. However, the reversion of all rubbers decreases with increasing palm oil fatty acid concentration. At similar concentrations of palm oil fatty acid, ENR 50 compounds exhibit the shortest scorch and cure times followed by ENR 25 and SMR L compounds. For reversion, SMR L compounds show the lowest value followed by ENR 50 and ENR 25 compounds, whereas for fatigue life, the highest value is obtained with ENR 50 compounds followed by ENR 25 and SMR L compounds. © 1999 Society of Chemical Industry  相似文献   

3.
The influence of epoxidation level of natural rubber (i.e., ENR25, ENR50) on the dielectric and oxygen gas barrier properties of thermally reduced graphene oxide (GR) and graphite (GT) (with 2%·w/w) filled nanocomposites are investigated here. GR, GT filled epoxidized natural rubber (ENR) nanocomposites were fabricated by mechanical mixing using environment friendly two‐roll mill mixing method. Raman spectroscopy and Fourier transform infrared spectroscopy studies were carried out to investigate the extent of chemical interactions between GR and ENR. Morphological studies were done using transmission electron microscopy to evaluate the distribution of GR and GT in the ENR. The improved gas barrier and dielectric properties of GT‐ENR and GR–ENR composites synthesized by a novel green ecofriendly method is correlated with the chemical interactions among GT, GR, and ENR. POLYM. ENG. SCI., 55:2439–2447, 2015. © 2015 Society of Plastics Engineers  相似文献   

4.
In this work, natural rubber (NR) and regenerated cellulose (cel II) latexes were co-coagulated and to the mixture epoxidized natural rubber (ENR) was added on a two-roll mill. The cellulose content was fixed at 20 phr while ENR content varied from 0 to 75 phr. The influence of ENR was studied through the cure characteristics, aging and dynamic-mechanical properties. The aging provides nanocomposites with better solvent resistance and increased tensile strength at ENR content of 25 phr. The results suggest that a new type of light-colored nanocomposites were obtained, which presented high mechanical performance and resistance to solvents.  相似文献   

5.
Khalifeh  Sara  Tavakoli  Mitra 《Iranian Polymer Journal》2019,28(12):1023-1033

Microstructural development of elastomeric nanocomposites based on (50/50 wt%) styrene butadiene rubber (SBR) and epoxidized natural rubber (50 mol% epoxidation, ENR50) as the rubber matrix including two types of carbon fillers, carbon black (CB) and functionalized multiwall carbon nanotube (NH2-MWCNT), which were prepared through melt mixing, was studied. The results from FTIR analysis show that there is interaction between functional groups on MWCNT surface and the rubber chains. The AFM analysis also indicates good dispersion of filler particles in the rubber phases. FESEM images from cryo-fractured surface of samples have revealed that nanotubes were rarely pulled out of matrix and their diameter increased, resulting from good interaction between MWCNTs and rubber chains. The DMA results confirm good interfacial interaction between them. Furthermore, the reduced difference between the two Tgs of phases (ΔTg) shows that the incorporation of 3 phr MWCNT into the blend leads to increment in rubber phase compatibility but at higher MWCNT content (5 phr) due to lower Mooney viscosity of SBR phase, MWCNTs tend to remain in this phase. The bound rubber was adopted to characterize the polymer–filler interaction, showing that bound rubber content has an increasing trend with increasing in fillers content. The cure rheometric studies reveal that MWCNTs accelerate the cure process due to the presence of amine groups on the nanotube surface. In addition, the mechanical properties of samples show an increasing trend by increasing nano-filler content.

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6.
Effects of different zinc borate (ZB) loadings on thermal, flammability and crystallinity properties of blends of 10 % rubber (9/1) natural rubber (NR)/epoxidised natural rubber (ENR)/metallocene linear low density polyethylene/N,N-m-phenylenebismaleimide/MgO were investigated. Fourier transform infrared spectroscopy revealed that –C=O and –OH groups appeared while C–O–C and C=C groups disappeared in all blend samples. ZB increased the activation of HVA-2 by changing the reaction mechanism and increasing the concentration of the –C=O groups in the blends due to the peak at 1,714–1,718 cm?1. The crystallinity of all blends was increased by ZB loading increase; therefore, it played the heterogeneous nucleation center and maximum crystallinity was observed at 6 phr ZB blend. The thermal stability of NR improved with increase of zinc borate loading and the highest thermal stability was determined for 8 phr ZB blend. Good compatibilization between the two rubbers (NR/ENR-50) was achieved in the presence of ZB, which was revealed by the presence of only one peak for their decomposition. The limiting oxygen index value of mLLDPE was decreased by two rubbers loading increase, while it was increased by ZB loading increase to provide fire barriers to protect flammable materials from thermal damage. It was concluded that ZB has a synergistic effect on the LOI values of flame retardant mLLDPE/rubber containing MgO.  相似文献   

7.
Novel degradable materials based on ternary blends of natural rubber (NR)/linear low-density polyethylene (LLDPE)/thermoplastic starch (TPS) were prepared via simple blending technique using three different types of natural rubber (i.e., unmodified natural rubber (RSS#3) and ENR with 25 and 50 mol% epoxide). The evolution of co-continuous phase morphology was first clarified for 50/50: NR/LLDPE blend. Then, 10 wt% of TPS was added to form 50/40/10: NR/LLDPE/TPS ternary blend, where TPS was the particulate dispersed phase in the NR/LLDPE matrix. The smallest TPS particles were observed in the ENR-50/LLDPE blend. This might be attributed to the chemical interactions of polar functional groups in ENR and TPS that enhanced their interfacial adhesion. We found that ternary blend of ENR-50/LLDPE/TPS exhibited higher 100 % modulus, tensile strength, hardness, storage modulus, complex viscosity and thermal properties compared with those of ENR-25/LLDPE/TPS and RSS#3/LLDPE/TPS ternary blends. Furthermore, lower melting temperature (T m) and heat of crystallization of LLDPE (?H) were observed in ternary blend of ENR-50/LLDPE/TPS compared to the other ternary blends. Also, neat TPS exhibited the fastest biodegradation by weight loss during burial in soil for 2 or 6 months, while the ternary blends of NR/LLDPE/TPS exhibited higher weight loss compared to the neat NR and LLDPE. The lower weight loss of the ternary blends with ENR was likely due to the stronger chemical interfacial interactions. This proved that the blend with ENR had lower biodegradability than the blend with unmodified NR.  相似文献   

8.
The viscosity, loop tack, and shear strength of silica‐filled epoxidized natural rubber (ENR 25 and ENR 50 grade) adhesive were investigated using coumarone‐indene as the tackifying resin. Silica loading was varied from 10–50 parts per hundred parts of rubber (phr), whereas the coumarone‐indene concentration was fixed at 40 phr. Toluene was used as the solvent throughout the study. Polyethylene terephthalate substrate was coated at various adhesive coating thicknesses, i.e., 30, 60, 90, and 120 μm using a SHEEN Hand Coater. Viscosity of the adhesive was determined by a HAAKE Rotary Viscometer whereas loop tack and shear strength were measured by a Llyod Adhesion Tester operating at 30 cm/min. Result shows that viscosity of the adhesive increases gradually with increase of silica loading due to the concentration effect of the filler. Both loop tack and shear strength show maximum value at 40 phr silica for ENR 25. However, the respective values for ENR 50 are 20 and 40 phr of filler. This observation is attributed to the maximum wettability and compatibility of adhesive on the substrate at the respective silica loadings. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

9.
The abrasion resistance of two grades of epoxidized natural rubber (ENR 25 and ENR 50) and one grade of styrene-butadiene rubber (SBR) were studied using an Akron abrasion tester. An accelerated sulfur vulcanization system with 2-mercaptobenzothiazole (MBT) as the accelerator is used throughout the study. Carbon black (N 330), precipitated silica, and calcium carbonate were chosen as the fillers. The range of sulfur and filler loadings was from 1 to 5 phr and 10 to 50 phr, respectively. Mixing was done on a two-roll mill. Results obtained show that for all the rubbers studied, the volume loss due to abrasion decreases with increasing sulfur loading and passes through a minimum at about 3 phr of sulfur. This observation is attributed to the changes of cross-link types from monosulfidic to polysulfidic crosslink as sulfur concentration is increased. However, further sulfur loading would cause a “tight” cure, thus increasing the abrasion loss. For sulfur loading less than 3 phr, ENR 25 indicates the highest abrasion loss, followed by SBR and ENR 50. For the filled stock, minimum loss is observed at about 35–40 phr of filler. Reinforcing filler such as carbon black exhibits better abrasion resistance than calcium carbonate, a nonreinforcing filler. The abrasion loss increases at higher filler loading due to the dilution effect of fillers. Ozone plays an important role in the abrasion property of unsaturated rubbers, as reflected by the higher abrasion loss in the presence of ozone.  相似文献   

10.
Poly (vinyl chloride), PVC/epoxidized natural rubber blend, ENR/carbon nanotubes, CNTs nanocomposites were prepared using melt intercalation and solution blending methods. In both preparation methods PVC: ENR: CNTs ratios were fixed at 50:50:2, while the 50/50 PVC/ENR blend without the addition of CNTs was used as control. The PVC/ENR/CNTs nanocomposites were exposed to electron beam (EB) irradiation at doses ranging from 0–200 kGy. The effects of two different preparation methods on the tensile properties, gel fraction and morphology of the PVC/ENR/CNTs nanocomposites were studied. Prior to EB irradiation, the addition of 2 phr of CNTs caused a drop in the tensile strength (Ts) of the 50/50 PVC/ENR blend, implying poor distribution of CNTs in the PVC/ENR blend matrix. However upon EB irradiation, the nanocomposites prepared by the melt blending method exhibited higher values of Ts as compared to the neat PVC/ENR blend due to occurrence of radiation-induced cross-linking in the PVC/ENR blend matrix. Transmission electron microscopy (TEM) images proved that a better dispersion of CNTs in PVC/ENR blend matrix can be achieved by melt intercalation compared to solution blending and the dispersion of CNTs was improved by irradiation. Scanning electron microscopy (SEM) results showed a distinct failure surface with formation of rough structure for the irradiated nanocomposites, which explains the higher values of tensile properties compared to the non-irradiated nanocomposites.  相似文献   

11.
Onium ion‐modified montmorillonite (organoclay) was melt compounded with natural rubber (NR) in an internal mixer and cured by using a conventional sulfuric system. Epoxidized natural rubber with 50 mol % epoxidation (ENR 50) was used in 10 parts per hundred rubber (phr) as a compatibilizer. The effect of organoclay with different filler loading up to 10 phr was studied. Cure characteristics were determined by a Monsanto MDR2000 rheometer, whereas the tensile, compression, and tear properties of the nanocomposites were measured according to the related ASTM standards. While the torque maximum and torque minimum increased slightly, both scorch time and cure time reduced with the incorporation of organoclay. The tensile strength, elongation at break, and tear properties went through a maximum (at about 2 phr) as a function of the organoclay content. As expected, the hardness, moduli at 100% (M100) and 300% elongations (M300) increased continuously with increasing organoclay loading. The compression set decreased with incorporation of organoclay. The dispersion of the organoclay in the NR stocks was investigated by X‐ray diffraction and transmission electron microscopy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1083–1092, 2006  相似文献   

12.
The present work examines the effect of two different specific surface areas of highly dispersible silica (HDS)-reinforced epoxidized natural rubber (ENR) composites. The influences of different blend ratio between ENRs consisting 25 and 50?mol% of epoxidation-based (ENR-25/ENR-50) composites was studied in detail. The primary objective is to investigate the interfacial area of HDS surface involved in filler-to-rubber interaction mechanisms for the better reinforcement. Notable improvement in overall properties of these green composites are corroborated with various meticulous characterization including cure characteristics, specific bound rubber content, physicomechanical, dynamic mechanical properties, etc. Increasing the specific surface area of HDS and their subsequent interface with ENR matrix invokes its superior dispersion. Small angle X-ray scattering (SAXS) has been used to analyze the particles network and clusters establishment in green composites. The present SAXS method provides a unique insight into the cluster formation according to the Beaucage model. However, SAXS results demonstrate that particles networks can be effectively suppressed by increasing specific surface area of HDS.  相似文献   

13.
Hygrothermally decomposed polyurethane (HD‐PUR) was mixed up to 20 phr in epoxidized natural rubber (with 50 mol % epoxidation; ENR50) recipes, and the curing and mechanical behaviors were studied. Mechanical testing of the ENR50/HD‐PUR vulcanizates determined the tensile, tear, compression‐set, hardness, abrasion, hysteresis, and resilience properties. No significant changes were observed in the tensile properties with the incorporation of HD‐PUR. The ENR50 compounds showed an increase in compression set with increasing HD‐PUR content. Rubbers cured by a semi‐efficient vulcanization system gave the best overall performance. A further improvement in curing and mechanical properties was achieved by the carbon black grade N330 being replaced with a more active grade (N375). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2265–2276, 2002  相似文献   

14.
The main objective of this work was to investigate influence of natural rubber (NR) types on mechanical, thermal, morphological, and curing properties together with relaxation behavior of geopolymer filled NR composites with and without bis(triethoxysilylpropyl) tetrasulfide (TESPT) silane coupling agent. Three alternative types of NR: unmodified NR, and epoxidized NR with 25 (ENR-25) or 50 mol % epoxide (ENR-50) were exploited. Rubber compounds filled with GP particles were prepared in an internal mixer at 60 °C and 130–150 °C for the ones with and without TESPT, respectively. It was found that incorporation of GP significantly affected cure characteristics and mechanical properties of the rubber composites. That is, decreasing cure time was observed from 11.6, 3.2, and 7.0 min in gum NR, ENR-25, and ENR-50 to 6.9, 2.1, and 5.0 min in NR/GP, ENR-25/GP, and ENR-50/GP compounds, respectively. Furthermore, the ENR-25/GP and ENR-50/GP composites showed finely dispersed GP particles which indicate high filler–rubber interactions. The in situ silanization with TESPT in rubber composites enhanced the mechanical properties of NR/GP and ENR-25/GP composites but no such enhancement was found in the ENR-50/GP composite. This matched the observations of Payne effect, maximum tan δ, and stress relaxation properties of the composites. We found that the ENR-25/GP composites exhibited the best overall properties. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47346.  相似文献   

15.
Mixing torque, morphology, tensile properties and swelling studies of natural rubber/ethylene vinyl acetate copolymer blends were studied. Two series of unvulcanized blends, natural rubber/ethylene vinyl acetate (SMRL/EVA) copolymer blend and epoxidized natural rubber (50% epoxidation)/ethylene vinyl acetate (ENR-50/EVA) copolymer blend were prepared. Blends were prepared using a laboratory internal mixer, Haake Rheomix polydrive with rotor speed of 50 rpm at 120°C. Results indicated that mixing torque value and stabilization torque value in ENR-50 blends are lower than SMRL blends. The process efficiency of ENR-50/EVA blends is better due to less viscous nature of the blend compared to SMRL/EVA blends as indicated in stabilization torque graph. Tensile properties like tensile strength, M100 (modulus at 100% elongation) and E b (elongation at break) increase with increasing EVA fraction in the blend. At the similar blend composition, ENR-50 blend shows better tensile properties than SMRL blends. In oil resistance test, swelling percentage increased with immersion time and rubber composition. At a similar immersion time, ENR-50 blends exhibit better oil resistance compared to SMRL blends. Scanning electron microscopy (SEM) of tensile fractured surface indicated that EVA/ENR-50 blends need higher energy to cause catastrophic failure compared to EVA/SMRL blends. In etched cryogenically fractured surface, size and distribution of holes due to extraction of rubber phase by methyl ethyl ketone (MEK) were studied and holes became bigger as rubber composition increased due to coalescence of rubber particle.  相似文献   

16.
High-temperature molding of Brabender-mixed blend of polyacrylic acid (PAA) and epoxidized natural rubber (ENR) causes thermally induced crosslinking between PAA and ENR. Studies on Monsanto rheometry of the blend and physical properties, solvent swelling, and dynamic mechanical properties of the molded blend show that both mixer rotor speed and carbon black filler influence the crosslinking between the component polymers. For example, the extent of crosslinking for the 50–50 PAA–ENR blend was found maximum when the component polymers were mixed at 40 rpm, but the same blend filled with 30 phr HAF carbon black filler showed maximum crosslinking when mixing was carried out at 120 rpm. The results have been explained on the basis of formation of network on the filler surface, which in turn depends on two competing factors: increase in bound rubber formation with increase in filler loading at a fixed rotor speed and enhanced degradation of ENR at higher mixer rotor speed at a fixed filler loading. © 1994 John Wiley & Sons, Inc.  相似文献   

17.
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.  相似文献   

18.
Loop tack, peel strength, shear strength, and morphology of (benzoyl peroxide)‐cured epoxidized natural rubber (ENR 25)/(acrylonitrile‐butadiene) rubber (NBR) blend adhesive were investigated by using petro resin as the tackifying resin. Benzoyl peroxide loading varied from 1 to 5 parts by weight per hundred parts of resin (phr), whereas the petro resin loading was fixed at 40 phr. A SHEEN hand coater was used to coat the adhesive on the polyethylene terephthalate substrate at 30 μm and 120 μm coating thicknesses. (ENR 25)/NBR adhesive was crosslinked at 80°C for 30 min prior to the determination of adhesion strength by a Lloyd adhesion tester operating at 10–60 cm/min. Results show that maximum loop tack and peel strength occur at 2 phr of benzoyl peroxide loading, whereby optimum cohesive and adhesive strength are obtained. However, shear strength increases with increasing benzoyl peroxide concentration, an observation that is associated with the steady increase in the cohesive strength. Scanning electron microscopy micrograph shows that little adhesive remained on the substrate at 0 phr compared with 2 phr of benzoyl peroxide loading, indicating that crosslinking increases the peel strength of the adhesive. In all cases, the adhesion properties increase with coating thickness and testing rate . J.VINYL ADDIT. TECHNOL., 24:93–98, 2018. © 2015 Society of Plastics Engineers  相似文献   

19.
The effects of epoxidized natural rubber (ENR‐50) and processing parameters on the properties of natural rubber/ethylene–propylene–diene rubber (NR/EPDM; 70 : 30 phr) blends were studied. The compounds were prepared by melt compounding method. Using response surface methodology of two‐level full factorial, the effects of ENR‐50 contents (?1 : 5 phr; +1 : 10 phr), mixing temperature (?1 : 50°C; +1 : 110°C), rotor speed (?1 : 40 rpm; +1 : 80 rpm), and mixing time (?1 : 5 min; +1 : 9 min) in NR/EPDM blends were evaluated. Cure characteristics and tensile properties were selected as the responses. The significance of factors and its interaction was analyzed using ANOVA and the model's ability to represent the system was confirmed using the constant of determination, R2 with values above 0.90. It was found that the presence of ENR‐50 has the predominant role on the properties of NR/EPDM blends. The addition of ENR‐50 significantly improved cure characteristics and tensile strength up to 5.12% and 6.48% compared to neat NR/EPDM blends, respectively. These findings were further supported by swell measurement, differential scanning calorimetry, and scanning electron microscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40713.  相似文献   

20.
This study aimed at preparing nanocomposite from epoxidized natural rubber with about 40 mol% epoxidation (ENR40), vinyl acetate ethylene copolymer (VAE) contained about 70 wt% acetate groups and nanosilica (nSiO2). Two parts by weight per hundred parts of rubber/resin of nSiO2 were assembled to 80/20 (w/w) ENR40/VAE blend via latex blending. The resulting nanocomposite latex was coagulated before compounding with curing agents in an internal mixer. Tetrabenzylthiuram disulphide was used as a non‐carcinogenic accelerator in three sulfur vulcanization/curing systems, namely conventional (CV), semi‐efficient (semi‐EV) and efficient (EV) systems. The rubber compounds were sheeted on a two‐roll mill and press‐cured using a compression molding machine. Influence of curing systems on cure characteristics, tensile properties, thermal stability, dynamic mechanical properties and oil resistance of the nanocomposites was investigated. The results revealed that the CV system exhibited the highest crosslink density, tensile properties and storage modulus, while the EV system exhibited the longest scorch and cure time and the highest thermal stability and oil resistance. Moreover, the percentage retention of the tensile properties after thermal aging for CV system was lower than that of semi‐EV and EV systems. However, the pristine ENR40 and 80/20 (w/w) ENR40/VAE blend were also prepared for comparison. J. VINYL ADDIT. TECHNOL., 25:E28–E38, 2019. © 2018 Society of Plastics Engineers  相似文献   

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