Effect of Blend Ratio and Testing Rate on the Adhesion Properties of Epoxidized Natural Rubber (ENR 25)/Styrene–Butadiene Rubber (SBR) Blend Adhesive

The effect of rubber blend ratio and testing rate on the adhesion properties of epoxidized natural rubber (ENR 25)/styrene–butadiene rubber (SBR) blend adhesive were studied using 40 parts per hundred parts of rubber (phr) of coumarone-indene resin as the tackifying resin. Toluene and poly(ethylene terephthalate) (PET) film were used as the solvent and substrate, respectively. A SHEEN hand coater was used to coat the adhesive on the PET substrate at 30, 60, 90, and 120 µm coating thickness. Viscosity was determined by a Brookfield viscometer whereas loop tack, peel strength, and shear strength were measured by a Llyod Adhesion Tester at various testing rates from 10 to 60 cm/min. Results show that viscosity increases gradually with % ENR 25. However, loop tack, peel strength, and shear strength of adhesives indicate a maximum value at 40% ENR 25, after which the adhesion properties decreases with further increase in % ENR 25. This observation is attributed to the varying degree of wettability which culminates at an optimum value of 40% ENR 25 blend ratio. In all cases, the adhesion properties increase with increasing coating thickness and rate of testing.     

Effect of Barium Chloride Filler on the Adhesion Properties of Epoxidized Natural Rubber (ENR 25)-Based Adhesives

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.     

Adhesion properties of (epoxidized natural rubber)/(ethylene‐propylene‐diene rubber) blend adhesive: Effect of blend ratio and testing rate

The adhesion properties of epoxidized natural rubber (ENR 25)/(ethylene‐propylene‐diene rubber) blend adhesive were investigated by using various blend ratios of the two rubbers and rate of testing. Coumarone‐indene resin was used as the tackifier. Results show that the loop tack and peel strength of adhesives increase steadily up to 60% ENR 25 before decreasing with further increase in % ENR 25. This observation is attributed to an increase in wettability and compatibility up to the optimum value of the ENR 25 blend ratio. However, shear strength increases continuously with increasing percentage of ENR 25, an observation that is ascribed to the increasing cohesive strength of the blend adhesive. In all cases, the adhesion properties increase with increasing coating thickness and testing rates. J. VINYL ADDIT. TECHNOL., 22:134–139, 2016. © 2014 Society of Plastics Engineers     

Cure and mechanical properties of filled SMR L/ENR 25 and SMR L/SBR blends

The effect of blend ratio of natural rubber/epoxidized natural rubber (SMR L/ENR 25) and natural rubber/styrene‐butadiene rubber (SMR L/SBR) blends on scorch time (t₂), cure time (t₉₀), resilience, hardness, and fatigue properties were studied in the presence of carbon black and silica. An accelerated sulfur vulcanization system was used throughout the investigation. The scorch and cure times of the rubber compound were assessed by using a Moving‐Die Rheometer (MDR 2000). Resilience, hardness, and fatigue life were determined by using a Wallace Dunlop Tripsometer, a Wallace Dead Load Hardness Tester, and a Fatigue to Failure Tester, respectively. The results indicate that t₂ and t₉₀ decrease with increasing ENR 25 composition in the SMR L/ENR 25 blend whereas both values increase with increasing SBR content in the SMR L/SBR blend. This observation is attributed to faster cure in ENR 25 and higher saturation in SBR. Resilience decreases with increase in % ENR and % SBR but hardness shows the reverse behavior in their respective blends. The fatigue life increases with % ENR, but it passes through a maximum with % SBR in the respective blends. In all cases, aging lowers the fatigue life, a phenomenon that is caused by the breakdown of crosslinks in the vulcanizate. Differences in all the observed values between carbon black‐filled and silica‐filled blends are associated with the varying degrees of interaction and dispersion of the two fillers in the rubber blend matrix. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 47–52, 2001     

Effect of zinc oxide on the viscosity,tack, and peel strength of ENR 25‐based pressure‐sensitive adhesives

Viscosity, loop tack, and peel strength of epoxidized natural rubber (ENR 25 grade)‐based pressure‐sensitive adhesive was studied in the presence of zinc oxide. The zinc oxide concentration was varied from 10–50 parts per hundred parts of rubber (phr). Coumarone–indene resin with loading from 20 to 100 phr was chosen as the tackifier resin. Toluene was used as the solvent throughout the experiment. The adhesive was coated on the substrate using a SHEEN hand coater to give a coating thickness of 60 μm. Viscosity of the adhesive was determined by a HAAKE Rotary Viscometer whereas the loop tack and peel strength were measured by a Llyod Adhesion Tester operating at 30 cm/min. Results show that viscosity and loop tack of adhesive increases with increasing zinc oxide concentration. For the peel strength, it increases with zinc oxide concentration up to 30–40 phr and drops after the maximum value. This observation is associated with the effect of varying degree of wettability of the adhesive on the substrate. However, for a fixed zinc oxide concentration, loop tack and peel strength exhibit maximum value at 80 phr resin loading after which both properties decrease with further addition of resin, an observation which is attributed to phase inversion. From this study, the optimum adhesion property is achieved by using 40 phr zinc oxide and 80 phr coumarone–indene resin. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of molecular weight of epoxidized‐natural rubber on viscosity and tack of pressure‐sensitive adhesives

The effect of molecular weight of rubber on viscosity and loop tack of rubber‐adhesives were studied using two grades of epoxidized‐natural rubber, i.e., ENR 25 and ENR 50. Coumarone–indene resin, gum rosin, and petro resin were used as tackifiers. Toluene was used as the solvent throughout the experiment. The adhesive was coated on polyethylene terephthalate (PET) substrate using a SHEEN hand coater. Viscosity was determined by a HAAKE Rotary Viscometer, whereas loop tack was measured by a Llyod Adhesion Tester operating at 10 cm/min. Results show that viscosity increases gradually upto a critical molecular weight of 6.8 × 10⁴ and 3.9 × 10⁴ for ENR 25 and ENR 50, respectively, before a rapid increase in viscosity is observed. Loop tack indicates maximum value at the respective critical molecular weights for the three tackifiers investigated suggesting the culmination of wettability. For both rubbers, loop tack increases with coating thickness due to the concentration effect of adhesive. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of Blend Ratio on Adhesion Properties of Pressure-Sensitive Adhesives Prepared from SBR/SMR L Blends

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.     

Effect of Testing Rate on Adhesion Properties of Benzoyl-Peroxide-Cured ENR 25/NBR Blend Adhesive Using Gum Rosin and Coumarone-Indene Resin as Tackifiers

Dependence of adhesion properties of benzoyl-peroxide-cured epoxidized natural rubber (ENR 25)/acrylonitrile-butadiene rubber (NBR) blend adhesive on testing rate was systematically studied. Coumarone-indene resin and gum rosin were used as tackifiers. Toluene was used as solvent throughout the study. The SHEEN hand coater was used to coat the adhesive on polyethylene terephthalate at 30 and 120 µm coating thickness. The adhesion properties were measured by a Lloyd adhesion tester operating at different rates of testing. Results showed that the loop tack, peel strength, and shear strength increased with increasing testing rate, an observation that was attributed to the viscoelastic nature of adhesive. In all cases, the adhesion properties of the adhesives also increased with increasing coating thickness.     

Effect of silica on viscosity,tack, and shear strength of epoxidized natural rubber‐based pressure‐sensitive adhesives in the presence of coumarone‐indene resin

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     

Adhesion property of crosslinked epoxidized (natural rubber)/(acrylonitrile‐butadiene) rubber blend adhesives in the presence of petro resin tackifier

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     

Effect of zinc oxide on the viscosity and adhesion property of epoxidized natural rubber/acrylonitrile‐butadiene rubber‐based pressure‐sensitive adhesives

Viscosity, loop tack, peel strength, and shear strength of epoxidized natural rubber (ENR 50)/acrylonitrile‐butadiene rubber (NBR)–based pressure‐sensitive adhesive were studied in the presence of zinc oxide. The zinc oxide concentration was varied from 10 to 50 parts by weight per hundred parts of rubber (phr). Coumarone–indene resin with loading of 40 phr was chosen as the tackifier resin. Toluene and polyethylene terephthalate were used as the solvent and coating substrate, respectively, throughout the experiment. The adhesive was coated on the substrate by using a SHEEN hand coater. Viscosity of the adhesive was determined by a Brookfield Viscometer, whereas the loop tack, peel strength, and shear strength were measured by a Lloyd Adhesion Tester operating at 30 cm/min. Results indicate that viscosity increases with zinc oxide concentration owing to the concentration effect. Loop tack and peel strength pass through a maximum value at 20 phr of zinc oxide concentration. This observation is associated with the effect of varying degrees of wettability of the adhesive on the substrate. Shear strength, however, increases steadily with increasing zinc oxide loading owing to the steady increase in cohesive strength. In all cases, the adhesion properties of adhesives increase with increasing coating thicknesses. J. VINYL ADDIT. TECHNOL., 22:410–414, 2016. © 2015 Society of Plastics Engineers     

Effect of Coumarone-Indene Resin on Adhesion Property of SMR 20-Based Pressure-Sensitive Adhesives

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.     

Dependence of Mooney scorch time of SMR L,ENR 25, and ENR 50 on concentration and types of antioxidants

The effect of concentration of antioxidants on the Mooney scorch time of two grades of epoxidized natural rubbers (ENR 25 and ENR 50) and one grade of natural rubber (SMR L) was studied using a Monsanto automatic Mooney viscometer (MV 2000). Three types of antioxidants, viz., 2,2′‐methylene‐bis(4‐methyl, 6‐tertbutylphenol) (AO 2246), N‐isopropyl‐N′‐phenyl‐p‐phenylenediamine (IPPD) and poly‐2,2,4‐trimethyl‐1,2‐dihydroquinoline (TMQ) were used, and the concentration range was varied from 0 to 5 phr. The conventional vulcanization system with 2‐mercaptobenzothiazole (MBT) as the accelerator was used throughout the study. Results show that increasing the phenol‐based antioxidant (AO 2246) concentration will increase the scorch time of ENR at a lower temperature of vulcanization while its effect on SMR L is not significant. This retardation effect is attributed to the “solvation” of epoxide group by the phenolic group in AO 2246, thus reducing the activation of adjacent double bond in ENR. The scorch time, however, is shortened by the amine‐based antioxidants (IPPD and TMQ) for the three rubbers studied, a phenomenon associated with the ability of the amine group to enhance the formation of more active sulfurating agent and subsequently increases the cure rate as the concentration of the amine‐based antioxidants is increased. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2940–2946, 1999     

Tensile,Tear and Swelling Properties of ENR 50/SBR Blend

Abstract

Tensile strength, tear strength and swell index of epoxidized natural rubber (ENR 50) blended with styrene-butadiene rubber (SBR) was studied. The blend ratio was varied from 0–100% of ENR 50. Accelerated-sulfur conventional vulcanization system was used throughout the study. Tensile property and tear strength of the blend were determined by Monsanto Tensometer (Model T10) and toluene was used as the solvent in the swell index experiment. Results show that tensile strength and elongation at break increases with ENR 50 up to about 70% ENR 50, whereas for the tear strength, it increases steadily with increasing ENR 50, an observation which is attributed to strain-induced crystallization of ENR. Similar behavior was observed with the aged sample though its absolute value is lower than that of the unaged sample. As for the swell index, it decreases gradually with increasing ENR indicating the increase in polarity of the blend as the blend ratio of ENR 50 is increased.     

Physico-mechanical properties and automotive fuel resistance of EPDM/ENR blends containing hybrid fillers

This research aimed to investigate the effect of blend ratios on cure characteristics, mechanical and dynamic properties, morphology and automotive fuel resistance of ethylene-propylene diene rubber (EPDM) and epoxidized natural rubber (ENR) blends containing carbon black and calcium carbonate hybrid filler. The composition of EPDM/ENR blends varied were 100/0, 70/30, 50/50, 30/70 and 0/100 %wt/wt. All ingredients used for preparing each blended compound, except for the curatives, were mixed in a kneader. Thereafter, the compound was further mixed with curatives on a two-roll mill and then were vulcanized together with shaped by compression molding before determining cure characteristics, mechanical properties, morphology and weight swelling ratio in three automotive fuels; gasohol-91, diesel and engine oils. The results indicated that Mooney viscosity and cure time of EPDM/ENR blends tended to decrease with increasing ENR content, while cure rate index and crosslink density increased. Tensile strength of all EPDM/ENR blends is lower than that of the individual EPDM and ENR. This is attributed to the incompatibility between nonpolar and polar nature of EPDM and ENR, respectively, supporting by the glass transition temperature form dynamic mechanical thermal analysis (DMTA) and scanning electron micrographs (SEM). Owing to the differences in polarity of automotive fuels and rubbers, weight swelling of EPDM/ENR vulcanizates decreased in diesel and engine oils, but increased in gasohol-91 with increasing in ENR content.     

Viscosity and Peel Strength of SMR 10-Based Pressure-Sensitive Adhesives

The viscosity and peel strength of a natural rubber-based pressure-sensitive adhesive was studied. One grade of natural rubber (SMR 10) and coumarone-indene resin were used as the elastomeric material and tackifier, respectively. Throughout the experiment, toluene was used as the solvent to prepare the adhesive. The effect of mastication time of rubber and tackifier concentration on the viscosity and peel strength of adhesive on various substrates was systematically investigated. The viscosity was measured using a HAAKE Rotary Viscometer. T-Test, 90° Adhesion To Steel (ATS), and 180° Adhesion To Steel (ATS) Tests were used to determine the peel strength of the adhesive. The results indicate that the viscosity of the adhesive increases with the resin content but decreases with mastication time. The peel strength generally increases with an increase in resin content except for the 20 min masticated sample. For all concentrations of the resin tackifier studied, the 10 min masticated sample exhibits the highest peel strength as compared to the corresponding values of the other masticated samples. This observation is attributed to the optimum wetting and formation of mechanical interlocking, and anchorage of the adhesive in pores and irregularities in the substrate for the former sample.     

Effect of molecular weight and testing rate on peel and shear strength of epoxidized natural rubber (ENR 50)‐based adhesives

The dependence of peel strength and shear strength of epoxidized natural rubber (ENR‐50)‐based pressure sensitive adhesive on molecular weight and rate of testing was investigated using coumarone‐indene as the tackifying resin. Toluene and polyethylene terephthalate were used as the solvent and substrate respectively, throughout the study. A SHEEN hand coater was used to coat the adhesive on the substrate at a coating thickness of 120 μm. All the adhesion properties were determined by a Llyod Adhesion Tester operating at different rates of testing. Result shows that peel strength and shear strength increases up to an optimum molecular weight of 4.2 × 10⁴ of ENR 50. For peel strength, the observation is attributed to the combined effects of wettability and mechanical strength of rubber at the optimum molecular weight, whereas for the shear strength, it is ascribed to the optimum cohesive and adhesive strength which enhances the shear resistance of the adhesive. Peel strength and shear strength also increases with increase in rate of testing, an observation which is associated to the viscoeslastic response of the adhesive. DSC and FTIR study confirms the miscibility of tackifier and the ENR 50. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Dependence of Adhesion Properties of Cross-linked Epoxidized Natural Rubber (ENR 25)-Based Pressure-Sensitive Adhesives on Benzoyl Peroxide Loading in the Presence of Gum Rosin and Petroresin Tackifiers

The effect of benzoyl peroxide loading on the adhesion properties of cross-linked epoxidized natural rubber (ENR 25)-based adhesives was studied using gum rosin and petroresin as tackifiers. Toluene and polyethylene terephthalate (PET) were used as solvent and coating substrate, respectively. The adhesion properties were determined by a Lloyd adhesion tester operating at 30 cm min^?1. Results indicate that the loop tack and peel strength of gum rosin and petroresin pass through a maximum value at 2 parts per hundred parts of rubber (phr) and 3 phr benzoyl peroxide concentration, respectively, an observation which is attributed to the optimum cross-linking of ENR 25 where optimum, cohesive and adhesive strength is obtained. The shear strength, however, increases steadily with increasing benzoyl peroxide loading due to the steady increase in the cohesive strength. At the optimum benzoyl peroxide concentration, the petroresin-based adhesive consistently exhibits higher adhesion properties compared to that of gum rosin-based adhesives. The adhesion properties of both adhesive systems increase with increasing coating thickness.     

Fatigue and hysteresis behavior of halloysite nanotubes‐filled natural rubber (SMR L and ENR 50) nanocomposites

The effect of various halloysite nanotubes (HNTs) loading on fatigue life, stress–strain behavior, and hysteresis of HNTs/Standard Malaysian Rubber (SMR) L and HNTs/epoxidized natural rubber (ENR) 50 nanocomposites were studied. The addition of HNTs caused decrement in fatigue life for both nanocomposites at any extension ratio. Generally, HNTs/SMR L nanocomposites showed higher fatigue life than ENR 50 nanocomposites. Addition of more HNTs caused decrement of stress for HNTs/SMR L nanocomposites, whereas HNTs/ENR 50 nanocomposites showed vice versa at any strain. This result was supported by the graph of accumulated strain energy against extension ratio. Hysteresis values increased with addition of HNTs in both nanocomposites where of HNTs/ENR 50 nanocomposites exhibited higher hysteresis than HNTs/SMR L nanocomposites at any HNTs loading. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

The Effect of Rice Husk Powder on Standard Malaysian Natural Rubber Grade L (SMR L) and Epoxidized Natural Rubber (ENR 50) Composites

The effects of rice husk powder (RHP) loading and two types of natural rubber matrix (SMR L and ENR 50) on curing characteristics and mechanical properties were studied. The scorch time and cure time decreased with increasing RHP loading whereas maximum torque showed an increasing trend. SMR L composites possessed longer scorch time and cure time than ENR 50 composites. Incorporation of RHP into both rubbers improved tensile modulus significantly but decreased tensile strength and elongation at break. SMR L composites exhibited the lower tensile modulus and higher tensile strength and elongation at break than ENR 50 composites.