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The effect of molecular weight of two grades of epoxidized natural rubber (ENR)—i.e., ENR 25 and ENR 50—on the peel strength of an adhesive is studied using coumarone-indene resin, gum rosin, and petro resin as tackifiers. Toluene and polyethylene terephthalate (PET) film acted as the solvent and substrate, respectively. A SHEEN hand coater was used to coat the adhesive on the substrate to give coating thicknesses of 30, 60, 90, and 120 µm. The peel strength of adhesive was determined using a Lloyd Adhesion Tester operating at 30 cm/min. Results show that peel strength has a maximum value at a molecular weight of 6.8 × 104 and 3.9 × 104 for ENR 25 and ENR 50, respectively, an observation which is attributed to the combined effects of wettability and mechanical strength of the rubber at the respective optimum molecular weight of ENR. Peel strength increases with coating thickness for all the tackifiers investigated, with a gum rosin-based adhesive exhibiting the highest peel strength. 相似文献
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《国际聚合物材料杂志》2012,61(3):247-255
The viscosity, tack, and peel strength of a natural rubber (SMR 20)–based pressure-sensitive adhesive (PSA) was studied using coumarone-indene resin as the tackifier. The resin loading was varied from 0–80 parts per hundred parts of rubber (phr). Toluene was used as the solvent throughout the experiment. The viscosity of PSA was measured using a Haake Rotary Viscometer whereas loop tack and peel strength were determined using a Lloyd Adhesion Tester. PSA was coated onto the substrates using a SHEEN hand coater to give a coating thickness of 60 μm and 120 μm. Results show that the viscosity and tack of the adhesive increases with resin content due to the concentration effect of tackifier resin. However, for the peel strength, it increases up to 40 phr of resin for both coating thickness, an observation that is attributed to the wettability of substrates. 相似文献
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Partheban Manoharan Tuhin Chatterjee Sanjay Pal Narayan Chandra Das 《Polymer-Plastics Technology and Engineering》2018,57(14):1452-1462
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
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Ming Zhou Noshir Pesika Hongbo Zeng Jin Wan Yonggang Meng 《The Journal of Adhesion》2013,89(11):1045-1058
According to the peel zone model proposed by Pesika et al. [8], the peel strength of an adhesive tape is proportional to the length of the peel zone or the bifurcation region at the peeling front between the tape backing and the substrate. In this study, the effects of the peel angle and peel velocity on the shape of the peel zone and the peel strength are further investigated theoretically and experimentally. The theoretical analysis on the angle at the edge of the peel zone, θ0, and the peel strengths at different peel velocities and angles was compared with experimental tests using three different commercial tapes. The experimental results are in good agreement with the extended peel zone model, which provides a simple approach to predict the peel strength of adhesive tapes with different physical properties at different peel angles and velocities. 相似文献
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The adhesion properties of epoxidized natural rubber (ENR 25)-based adhesive were studied using barium chloride, coumarone-indene resin and toluene as the filler, tackifier and solvent respectively. Viscosity was determined by a Brookfield Viscometer whereas tack, shear and peel strength was measured by a Llyod Adhesion Tester. Results show that viscosity of adhesive increases gradually with increasing barium chloride loading. Loop tack, shear and peel strength indicates a maximum value at 10 parts per hundred parts of rubber (phr) of barium chloride, an observation that is attributed to the maximum wettability and compatibility of adhesive on the substrate. 相似文献
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《国际聚合物材料杂志》2012,61(3-4):597-615
Abstract The cure time of accelerated sulphur vulcanization of Epoxidized Natural Rubber (ENR 25) was studied while one grade of unmodified natural rubber– Standard Malaysian Rubber Light (SMR L) was used as a control. Five accelerators, viz. 2-mercaptoben-zothiazole (MBT), tetramethylthiuram disulphide (TMTD), zinc dimethyldithiocarbamate (ZDMC), N-tert-butyl-2-benzothiazylsulphenamide (TBBS) and diphenylguanidine (DPG) were used in the study and the vulcanization systems used were conventional vulcanization (CV), semi-efficient vulcanization (semi-EV) and efficient vulcanization (EV). Monsanto Moving-Die Rheometer (MDR 2000) was used to determined the cure time in the temperature range of 100-180°C. The results indicate that cure time decreases exponentially with increasing temperature for the two rubbers studied. At a fixed curing temperature, ENR 25 shows shorter cure time compared to that of SMR L. This has been attributed to the activation of the double bond by the adjacent epoxide group in ENR 25. Studies of the effect of varying amounts of M Bata a fixed sulphur concentration show that cure time decreases as the accelerator concentration increases. ENR 25 shows higher torque maximum than SMR L. This observation can be related to the oxirane group which is bulky and thus accounts for increased glass; transition temperature with increase in the level of epoxidation. Of the vulcanization systems, CV shows the highest torque maximum followed by semi-EV and than EV. This trend can be attributed to the amount of active sulphurating agent which increases with increasing accelerator concentration. It was also found that the influence of accelerator/sulphur ratio becomes less significant as vulcanization temperature increases. 相似文献
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Laminates consisting of natural rubber (NR) sandwiched between cloth fabric and polyester film were pulled apart at various rates and temperatures in a T-peel geometry. Peel energies for joints containing uncrosslinked or lightly-crosslinked NR did not obey simple time-temperature superposition. This behavior is attributed to strain-induced crystallization during peeling. However, when the rubber was highly crosslinked, strain crystallization seems to be absent, as peel energies now can be WLF shifted to form a mastercurve. 相似文献
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Laminates consisting of natural rubber (NR) sandwiched between cloth fabric and polyester film were pulled apart at various rates and temperatures in a T-peel geometry. Peel energies for joints containing uncrosslinked or lightly-crosslinked NR did not obey simple time-temperature superposition. This behavior is attributed to strain-induced crystallization during peeling. However, when the rubber was highly crosslinked, strain crystallization seems to be absent, as peel energies now can be WLF shifted to form a mastercurve. 相似文献
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The effects of rubber content, rate of peel and temperature on peel strength of ATBN modified DGEBA based epoxy resin adhesives have been investigated. The fracture surfaces of peel test specimens and the distribution of rubber particles in cured bulk epoxy resin have been observed with SEM and TEM, respectively. The mechanical properties of bulk rubber modified epoxy resin have been also measured. The peel strengths increased with increasing rubber content, peel rate, and decreasing temperature. The peel strengths were superposed as a function of rate and temperature. Plots of the shift factors against temperature gave two straight lines, which followed an Arrhenius relationship. The region of temperature below the intersection of the two straight lines, temperature somewhat lower than Tg of epoxy adhesive, gave markedly high peel strengths and a stick-slip failure due to plastic deformation of the adhesive, and a number of micro holes produced by the rupture of rubber micro particles on the fracture surface. The region of temperature above the intersection gave lower peel strengths and an apparent interfacial failure with ductile fracture of the adhesive, and larger, shallow holes or no holes. From these results, the marked increase of peel strength was concluded to be mainly attributed to the plastic or viscoelastic deformation of epoxy matrix, the strong bond at the interface between rubber particles and epoxy matrix, and the dilation and rupture of a number of rubber particles. 相似文献
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Studies on adhesion between natural rubber (NR) and polyethylene (PE) with different levels of interaction (physical and chemical) have been carried out. Ethylene propylene diene rubber (EPDM) and chlorinated polyethylene (CPE) were used as physical promoters and epoxidised natural rubber/modified polyethylene (ENR/PEm) and sulfonated ethylene propylene diene rubber/modified polyethylene (S-EPDM/PEm) were used as chemical adhesion promoters. The failure surfaces were examined with the help of scanning electron microscopy (SEM), optical photography and electron spectroscopy for chemical analysis (ESCA) techniques.
The peel strength between natural rubber and polyethylene as measured in this study is 140 J/m2. With the incorporation of physical promoters such as EPDM, the peel strength increases twenty fold because of structural similarity of EPDM with PE and the rubbery nature of EPDM. Similarly, the other promoters show significant improvement in peel strength. At high temperature and low rate of peeling, the nature of failure is mainly “stick-slip” for joints with interaction promoters. The average peel strength increases with increase in test rate and decrease in test temperature for most of the joints. All the data could be shifted onto a master curve indicating that the increase in strength is a result of viscoelastic dissipation. NR/EPDM/PE and NR/CPE/PE systems, however, behave in a different way probably because they alter the nature of crack propagation at or near the interface. ESCA results of the peeled PE surface show a chemical shift of C1S peak. SEM photographs also indicate interaction at the interface when modifiers are used. An increase in crystallinity of PE from 30% to 64% and modulus increase the peel strength of NR/PE joints by a factor of four. The results of peel strength measurement at 90° are lower than those at 180°. Lap shear results are in line with peel strength. 相似文献
The peel strength between natural rubber and polyethylene as measured in this study is 140 J/m2. With the incorporation of physical promoters such as EPDM, the peel strength increases twenty fold because of structural similarity of EPDM with PE and the rubbery nature of EPDM. Similarly, the other promoters show significant improvement in peel strength. At high temperature and low rate of peeling, the nature of failure is mainly “stick-slip” for joints with interaction promoters. The average peel strength increases with increase in test rate and decrease in test temperature for most of the joints. All the data could be shifted onto a master curve indicating that the increase in strength is a result of viscoelastic dissipation. NR/EPDM/PE and NR/CPE/PE systems, however, behave in a different way probably because they alter the nature of crack propagation at or near the interface. ESCA results of the peeled PE surface show a chemical shift of C1S peak. SEM photographs also indicate interaction at the interface when modifiers are used. An increase in crystallinity of PE from 30% to 64% and modulus increase the peel strength of NR/PE joints by a factor of four. The results of peel strength measurement at 90° are lower than those at 180°. Lap shear results are in line with peel strength. 相似文献
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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
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聚氨酯/聚烯烃互穿网络粘合剂的研究 总被引:4,自引:0,他引:4
制备了聚酯聚氨酯/聚丙烯酸酯及其它乙基单体聚合物热塑性互穿网络弹性体,将其溶解于溶剂中形成聚氨酯/聚烯烃粘合剂。考察了乙烯基单体的种类、用量、聚酯分子量、热活化时间等对粘合剂粘合性能的影响,同时测定了互穿网络弹性体的形态结构。 相似文献
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The viscosity, tack, and peel strength of an SBR/SMR L-based pressure-sensitive adhesive was studied. Coumarone–indene resin and toluene were used as the tackifier and solvent, respectively, throughout the experiment. The blend ratio of SBR/SMR L was varied from 0 to 100% whereas the resin content was increased from 40 to 120 parts per hundred parts of rubber in the adhesive formulation. The viscosity was determined by a HAAKE rotary viscometer. Loop tack and peel strength of paper/polyethylene terephthalate film were measured using a Lloyd adhesion tester operating at 30 cm/min. Results show that the viscosity of the adhesive decreases with % SBR but increases with resin loading. Loop tack of adhesive indicates a maximum value at 20% SBR for all resin loadings. The peel strength, however, exhibits maximum value at 40% SBR for the three modes of peel tests, an observation which is attributed to the optimum wettability of adhesive on the substrate where formation of mechanical interlocking and anchorage of the adhesive in pores and irregularities in the substrate occurs. 相似文献
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The curing properties and adhesive strengths of the epoxidized natural rubber (ENR, 25 mole percent epoxidation) modified epoxy systems are studied with differential thermal calorimetry (DSC), scanning electron microscopy (SEM), and lap shear strength (LSS) measurement. The results of DSC analyses indicate that the curing exotherm, the curing rate, the reaction order, and the glass transition temperature of the epoxy system are affected by the presence of reactive ENR. From SEM micrographs, it is obtained that a second spherical rubber phase is formed during cure and the particle size of the rubber phase is increased by increasing the curing temperature and the ENR content. The changes of the volume fraction of the rubber phase and the Tg of the cured systems indicate that the mutual dissolution between epoxy resin and ENR happens and which changes with the curing temperature and the ENR content. The LSS of adhesive joints prepared with the ENR modified adhesives are all lower than those of the unmodified epoxy system, and decrease with increasing the amount of ENR added because of the limited compatibility of the ENR with the epoxy matrix. 相似文献
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The effect of epoxidized natural rubber (ENR) or polyethylene acrylic acid (PEA) as a compatibilizer on properties of ethylene vinyl acetate (EVA)/natural rubber (SMR L) blends was studied. 5 wt.% of compatibilizer was employed in EVA/SMR L blend and the effect of compatibilizer on tensile properties, thermal properties, swelling resistance, and morphological properties were investigated. Blends were prepared by using a laboratory scale of internal mixer at 120°C with 50 rpm of rotor speed. Tensile properties, thermal properties, thermo-oxidative aging resistance, and oil swell resistance were determined according to related ASTM standards. The compatibility of EVA/SMR L blends with 5 wt.% of compatibilizer addition or without compatibilizing agent was compared. The EVA/SMR L blend with compatibilizer shows substantially improvement in tensile properties compared to the EVA/SMR L blend without compatibilizer. Compatibilization had reduced interfacial tension and domain size of ethylene vinyl acetate (EVA)/natural rubber (SMR L) blends. 相似文献