Acrylic Rubber Research Articles

Performance of diamond-like carbon-protected rubber under cyclic friction. I. Influence of substrate viscoelasticity on the depth evolution

In this paper, the influence of the viscoelastic properties of rubber substrate on the tribological behavior of DLC film-coated alkyl acrylate rubber is studied. The mechanical behavior of the rubber was first characterized by creep experiments using spherical indentations. The results were adjusted using a delayed elasticity model, and a numerical simulation of the indentation of the sliding counterpart ball during the tribotest was carried out. The results show a progressive increase of the contact depth, which is in agreement with the experimental observations.

Study on Application of the Blends of Nitrile Rubber with Acrylate Rubber in the Coat-Metal Sealing Gasket

This paper discussed the effect of different blending ratio with BNR and ACM on the mechanical properties, heat resistance, low temperature resistance and oil resistance of coat-metal sealing gasket. The result showed that the comprehensive properties of the NBR/ACM blends at the ratio of 85/15 were preferable to the NBR and ACM, the low temperature resistance and oil resistance of NBR are taken into account. The cost of the blends were lower than the ACM. The blends can be used for coat-metal sealing gasket instead of NBR.

Utilization of ultrafine acrylate rubber particles as a toughening agent for poly(lactic acid)

Abstract The present research aims to utilize ultrafine elastomeric particles to reduce the problem of brittleness in poly(lactic acid) (PLA). Particles of acrylate rubber were added to PLA at the range from 0.1 to 10 wt%. Maximum reduction of the flexural modulus and the tensile modulus was achieved by 20 and 45% respectively when the acrylate rubber was applied at 10 wt%. The tensile elongation at break of the rubber-modified PLA was also raised around 50 times from the 3.5% observed in the neat PLA to 200%. The toughening efficiency of the ultrafine rubber particles was also reflected through the significant increase in the impact strength by fourfolds. Fractographs of the acrylate rubber-modified PLA verified plastic deformation and good dispersion of the rubber particles in the PLA. Microscopic observation revealed that the ultrafine acrylate rubber played an important role inducing numerous crazes as the mechanism for energy absorption. The introduction of the ultrafine acrylate rubber particles by only 0.5 wt% helped increasing the degree of crystallinity.

Preparation and Property Study of PMMA/ASA Alloy

Polymethyl methacrylate (PMMA)/ acrylonitrile-styrene-acrylate terpolymer (ASA) alloy was prepared via melt blending method. Effects of ASA melt flow rate and PMMA/ASA ratio on mechanical property of the alloy were studied. It showed that when the high melt flow rate ASA was used, alloy’s tensile strength and flexural strength were little different from using low melt flow rate ASA, while the impact strength was significantly higher than the latter. Differential scanning calorimetry (DSC) analysis showed that a glass transition (Tg) platform emerged in low melt flow rate ASA at 48.5°C, which represented the Tg of the interface phase formed between SAN grafted acrylate rubber particles and SAN matrix. Scanning electron microscope (SEM) experiment further showed that when low melt flow rate ASA was used, alloy’s cross section was smooth which showed the characteristics of brittle fracture.

Effect of acrylate rubber on thermal and crystallization behavior of nylon 6

The thermal behavior of blends of nylon 6 (PA6, nylon 6)/acrylate rubber which were obtained by melt processing have been investigated by differential scanning calorimetry. The differential scanning calorimetry result indicates that the melting temperature and the crystallization temperature of blends decrease lightly with the increase of acrylate rubber content in the blends. The crystallization behavior of the blends studied by wide angle X-ray diffraction reveals that a γ→α crystal transformation occurs upon adding acrylate rubber into nylon 6. Furthermore, the crystallinity and crystal size decrease with adding acrylate rubber into nylon 6. The crystal morphology of nylon 6 and nylon 6/acrylate rubber blends was observed by the polarizing microscope. It is found that the crystal size of nylon 6/acrylate rubber gradually becomes smaller and crystal morphology of nylon6 / acrylate rubber gradually becomes imperfect with the increase of acrylate rubber content in the blends.

Metal-electrode-sandwiched quartz crystal-based oscillator as proximity sensor

A quartz crystal (QC) is a thermostable and high-quality material. The present paper proposes for the first time a QC-based oscillator as a proximity sensor. Various targets on a positioner were pushed into the oscillator. The dielectric target plate exhibited a minimal frequency shift compared with the semiconductor and other various metal plates. The metal-electrode-sandwiched QC showed a higher resonance frequency shift for target plates with higher conductivities. These results suggested that the inductive proximity effect was more dominant than the capacitive proximity effect. The dependence of the amplitude of the induced current on the gap between the target and the QC is also revealed. The QC coated with an acrylic rubber compound enhanced the frequency shift, although it may have also caused more frequency fluctuations during the measurements. A high detectable force slope may explain the higher sensitivity of the coated QC to the induced current.

The role of dicumyl peroxide in the preparation of chloroprene rubber/starch/sodium acrylate water-swellable composites

Water-swellable composites were prepared by blending sodium acrylate (NaAA), additives, and chloroprene rubber (CR)/starch masterbatch which was pre-formed by latex compounding method. The effects of the content of dicumyl peroxide (DCP) on the properties of the composites were investigated. We found that an increase in DCP amount led to a large increase in water swelling ratio and meanwhile a decrease in the mass loss ratio. Further, the composites were swollen uniformly in water and thus kept their original shapes well. The hardness and stresses at 100% and 300% increased with the increase in DCP amount. The addition of DCP facilitated the homopolymerization of NaAA while decreased the esterification reaction between NaAA and CR, which was verified by vulcanization curves, DSC and FT-IR. The morphology of the composites before and after water immersion was observed by optical transmission microscopy and indicated that the starch was homogenously dispersed in the composites.

Tribological performance of DLC films deposited on ACM rubber by PACVD

In this paper the tribological and adhesive performance of DLC films prepared by plasma assisted chemical vapor deposition on acrylic rubber (ACM) are studied. The effect of applied load and sliding velocity on the coefficient of friction and wear rate has been investigated. Effects of the rubber substrate and of ageing of the coated samples have also been explored. In addition, the adhesion of the DLC films to the rubber substrates is evaluated via stretch tests and the measured adhesion strength is larger than 40 MPa, indicating a superb adhesion to the substrate. It is shown that the tribological performance is greatly influenced by the viscoelastic properties of the substrate, and higher coefficients of friction are obtained at higher loads and velocities. The wear followed a similar trend, although very low in all the cases.

Microstructure and chemical bonding of DLC films deposited on ACM rubber by PACVD

The microstructure and chemical bonding of DLC films prepared by plasma assisted chemical vapor deposition on acrylic rubber (ACM) are studied in this paper. The temperature variation produced by the ion impingement during plasma cleaning and subsequent film deposition was used to modify the film microstructure by controlling the different degrees of strain applied to the substrate. The film microstructure is studied by top view and cross sectional SEM. The observed patch sizes are correlated with the variation of temperature that occurred during deposition. Finally, the chemical bonding of the samples is studied by Raman spectroscopy. All the samples show similar spectra regardless the bias voltage used.

Electrical Properties of Novel Lead Zirconate/Synthetic Rubber Composite Materials

Problem statement: Perovskite lead zirconate exhibits in an orthorhombic formation at a temperature below the Curie temperature, TC. Approach: The orthorhombic is non-centrosymmetric which is capable of spontaneous polarization (electronic, ionic and orientation), depending on their composition and volume fraction. Results: The results from FTIR spectroscopy, XRD patterns, and SEM indicate that the lead zirconate particles are dispersed in Acrylic Rubber (AR72) matrix. At a small amount of lead zirconate particulates present in the AR72 matrix, at nearly 0.3986% V/V (AR72/PZ_5), the electrical conductivity increases dramatically by two orders of magnitude. Conclusion/Recommendations: Our synthetic Rubber (AR72)/lead Zirconate (PbZrO3) composite materials can be successfully used as the candidate materials of soft Electroactive (ER) actuators, sensors, artificial muscles, and smart engineering devices.

Radiation induced graft copolymerization of n-butyl acrylate onto poly(ethylene terephthalate) (PET) films and thermal properties of the obtained graft copolymer

n-Butyl acrylate (BA) was successfully grafted onto poly(ethylene terephthalate) (PET) film using simultaneous radiation induced graft copolymerization with gamma rays. When BA concentration ranges from 20% to 30%, the Degree of Grafting (DG), measured by gravimetry and 1H NMR, increases with the monomer concentration and absorbed dose, but decreases with dose rate from 0.83 to 2.53 kGy/h. The maximum DG can reach up to 22.1%. The thermal transition temperatures such as glass-transition temperature ( T g) and cold-crystallization temperature ( T cc) of PET in grafted films were little different from those in original PET film, indicating that microphase separation occurred between PBA side chains and PET backbone. This work implied that if PET/elastomers (e.g., acrylate rubber) blends are radiated by high energy gamma rays under a certain condition, PET-g-polyacrylate copolymer may be produced in-situ, which will improve the compatibility between PET and the elastomers so as to improve the integral mechanical properties of PET based engineering plastic.

Electroactive alumina particles embedded in an acrylic elastomer

AbstractComposites of alumina particles embedded in a polar acrylic rubber polymer matrix are being investigated as potential electroactive polymer actuators. The measured FTIR spectra, XRD patterns, and SEM micrographs suggest that the alumina particles with an average diameter of 9.873 ± 0.034 μm having the rhombohedral form of the corundum phase are intercalated homogeneously within the acrylic rubber matrix. At an Al2O3 volume fraction of 0.144, the electrical conductivity increases from 10−9 to 10−8 (Ω m)−1 at 500 Hz. The storage modulus without applied electrical field, G′o, increases from 9,533 to 105,540 Pa, an order of—a single—magnitude increase, as the particle volume fraction is varied from 0 to 0.144. The increase in the matrix rigidity of the hybrid organic‐inorganic composites are because of the stress transfer from matrix to the reinforcement particles, the partial substitution of a soft matrix with a stiffer filler, and the segmental immobilization caused by the interaction between the matrix polymer chains and the filler surface. Under an applied electric field, induced dipole moments and particle‐particle interaction are generated, leading to an increase in the matrix rigidity. Under an applied electrical field, G′2 kV/mm increases from 9,775 to 139,080 within the same volume fraction range, a difference of more than 30% is observed because of presence of an electrical field. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers

Microstructural and frictional control of diamond-like carbon films deposited on acrylic rubber by plasma assisted chemical vapor deposition

In this paper we concentrate on the microstructure of diamond-like carbon films prepared by plasma assisted chemical vapor deposition on acrylic rubber. The temperature variation produced by the ion impingement during plasma cleaning and subsequent film deposition was monitored and controlled as a function of bias voltage and treatment time. Its influence during film growth on the appearance of patterns of cracks and wrinkles, caused by the thermal stresses is evaluated. Different growth modes are proposed in order to explain the smaller patch sizes observed at negative variations of temperature. The coefficient of friction (CoF) of the samples is measured using a pin-on-disk tribometer in non-lubricated conditions. Much lower CoF values than unprotected rubber are seen, which can be correlated with the observed patch size.

The Influence of Lubrication on Two-body Abrasive Wear of Sealing Elastomers Under Reciprocating Sliding Conditions

Elastomeric seals are prone to failure caused by abrasion during sliding against rough surfaces. In this research, the two-body abrasive wear of some selected sealing elastomers (nitrile rubber, hydrogenated nitrile rubber, acrylic rubber, and fluoro rubber) in dry and lubricated conditions has been studied. The influence of three different oils (synthetic ester, polyalphaolefin, and mineral oil) on the abrasive wear of the elastomers, at varying normal load and abrasive particle size, has been studied. The results show that, depending on the material, lubricant, abrasive size, and normal load, the abrasive wear of elastomers may increase or decrease in the presence of lubricants, and in most cases, the abrasive wear in the lubricated condition is higher than that in the dry condition. The influence of lubricant on the increase in abrasive wear is more significant during sliding against fine abrasives. Apart from the acrylic rubber, increase in the abrasive wear in presence of the synthetic ester is higher than those in presence of the mineral oil and polyalphaolefin.

Two body abrasive wear and frictional characteristics of sealing elastomers under unidirectional lubricated sliding conditions

Since abrasion is a common cause of seal failures, understanding the mechanisms of abrasion of an elastomer in the presence of lubricants is of importance in sealing applications. In this research a block on ring configuration was used to study the influence of lubrication on the two body abrasion of several commonly used sealing elastomers (two acrylonitrile butadiene rubbers, an acrylic rubber and a fluoro rubber). The friction force and the abrasive wear of the samples were measured and the worn surfaces and wear particles were investigated using an optical microscope. The tear strength of the elastomers before and after immersion in monoester oil as well as the oil absorption has been measured. Both scratches (parallel to the direction of sliding) and ridges (perpendicular to the direction of sliding) were observed on the worn surfaces of nitrile rubbers but the surfaces of acrylic and fluoro rubber were characterised by scratches only. The worn surfaces of nitrile rubbers were defined with more continuous ridges at lower sliding velocity and the presence of a lubricant in the contact reduced the continuous ridges. Examination of the wear particles shows that the wear particles (particularly for acrylic rubber) under dry sliding condition were aggregated, but the lubricant dispersed the wear particles and prevented aggregation. In most cases, abrasive wear of the elastomers under lubricated condition is higher than that under dry condition. The results show that the friction coefficient increased with increasing sliding velocity and decreased with contact pressure. Apart from the fluoro rubber, the friction coefficient as well as the tear strength of the elastomers decreased significantly in the presence of lubricant, particularly for acrylic rubber.

Properties of Natural Rubber Filled with Ultra Fine Acrylate Rubber Powder

Properties of natural rubber (NR) filled with various loadings of ultra-fine vulcanized acrylate rubber powder (ACMP) were investigated. ACMP loading was varied from 0 to 20 phr and, after compounding, the compound properties were determined. Results reveal that increasing ACMP loading leads to improved processability, as evidenced by the reduction of both mixing energy and Mooney viscosity. ACMP, however, has negative effect on cure, that is, both scorch time and optimum cure time are prolonged while the state of cure is reduced with increasing ACMP loading. Due to the reinforcing effect of the fine ACMP particles, both modulus and hardness are found to increase consecutively with increasing ACMP loading. The tensile strength is also found to improve with increasing ACMP loading up to 10 phr. However, due to the cure retardation effect and the high thermoplastic nature, the presence of ACMP causes deterioration of elasticity. As ACMP is highly polar and fully saturated, the addition of ACMP enhances the resistance to oil and thermal aging of the NR vulcanizate. Significant improvement of thermal aging resistance is found when 10 phr or more of ACMP is added.

Acrylic Rubber Latex in Ferrocement for Strengthening Reinforced Concrete Beams

Problem statement: In India, the early deterioration of reinforced concrete structures has become a big social problem in recent years. An essential research is needed for the development of effective repair materials and their execution systems comes to an important issue from the viewpoint of the longevity of infrastructures at present. Ferrocement laminates are introduced to enhance the overall performance of Reinforced Concrete (RC) structures and these days the use of it is a promising technology for increasing the flexural strength of deficient reinforced concrete members. Approach: The repair system aims to provide quantitative repair enhancement as well as extending the life of deteriorated concrete members. This research in particular inspired the initiation of the present work which aimed to develop a material with unique properties and a very wide range of practical applications. The mechanical properties of mortar through difference in polymer content with Acrilic Latex by ferrocement among three different volume fractions of mesh reinforcement were studied. Following the encouraging progress made in the formulation and evaluation of the polymer modified repair mortar, tests were carried out involving the application of the reinforced repair material to the soffit of the reinforced concrete beams of 3 m length. Results: The levels of damage of the original beams prior to repair did not affect the ultimate load of the strengthened beams tested. The performance of the strengthened beams was compared to the control beams with respect to cracking, deflection and ultimate strength which confirm preeminent results. Conclusion: This accomplished the fact that acrylic rubber latex modified ferrocement is a doable alternative strengthening component for the rehabilitation of reinforced concrete structures. Further developments in these systems will create dramatic improvement into the field of rehabilitation of old privileged structures.

Microstructure and Physical Properties of Acrylic Rubbers Filled with Montmorillonite in the Emulsion Polymerization Process

Montmorillonites (MMT) treated with various organic amines were added to the acrylic rubber in the polymerization process. Effects of the kind of organic amines, the contents of added MMT, and the method of the addition of MMT to the acrylic rubber on the dispersion state of MMT in the matrix and on the mechanical property of the obtained rubber were studied. As a result, the remarkable improvement of the mechanical property was achieved when 5 wt% of MMT organically treated with the laurylamine was added, although the deterioration of the mechanical property was observed at higher MMT contents. On the other hand, the mechanical property of the sample, to which MMT was added in the solution state, was improved gradually with the MMT content without showing a significant deterioration. Although the addition of organically treated MMT having a hydrophobic surface was added in the aqueous emulsion polymerization system, an excellent dispersion state was achieved when 5 wt% of MMT treated with laurylamine was added. Moreover, comparing with the friction property, the heat resistance, and the water resistance of the acrylic rubber added with MMT to those of the acrylic rubber added with the white carbon, it was proved that the addition of MMT significantly improve various physical and practical properties of the acrylic rubber.

Study on Slicing for Soft Composite Materials by Cutting Method

Soft composite materials are used for a functional film for a thermal interface material. The surface of this functional film must be flatter and thinner, and contacting fillers to have a better thermal conductivity. Cutting would meet these requirements to slice such soft materials. Soft composite materials consisting of acrylic rubber bulk and graphite fillers were prepared and sliced into films (1mm thickness) as thermal interface materials by developed cutting method. Measurements of curl radius and cutting forces were conducted on the orthogonal cutting experiments. It was found that the following three strategies were effective for reducing curl of chip and cutting force : (1) higher operating temperature, (2) slower cutting speed, and (3) larger tool rake angle. This result suggested a useful method for the effective slicing by controlling the cutting conditions.

Characteristics of Acrylic Rubber Composites with Mica and Carbon Black

In this work mica or carbon black were used as filler in composites of acrylic rubber (ACM). The fillers differ not only in nature, mica being a mineral material and carbon black being organic, but also in form and particle size. The content of filler varied from 0 to 50 phr and its influence on ACM was evaluated based on cure parameters, mechanical, and swelling properties. The cure parameters allow the conclusion that the presence of mica does not have a negative effect on the cure or processability; the swelling results indicated a weak interaction between ACM and mica even though the mechanical properties of ACM composition with 40 phr of mica were found to be similar to those of 20 phr carbon black. As a result of mica being less expensive than carbon black, is light colored and easily processible, these properties are of industrial importance. All properties analyzed were compared with gum type composition (without filler).