Swelling Of Rubber Research Articles

Effect of Complex Well Conditions on the Swelling and Tribological Properties of High-Acrylonitrile Stator Rubber in Screw Pumps.

The effects of complex well conditions in shale oil wells on the swelling and tribological properties of high-acrylonitrile stator rubber used in screw pumps were investigated in this study. Tests were conducted considering the combined effects of immersion medium, temperature, and duration. The key parameters measured included mass change rate, volume change rate, hardness, elongation at break, tensile strength, surface micro-morphology of the rubber after thermal expansion and swelling, friction coefficient, and wear quantity. The results indicated that in the actual well fluids, the mass change rate of high-acrylonitrile rubber ranged from -1.08% to 1.29%, with a maximum volume change rate of 2.78%. In diesel oil, the greatest mass change rate of the rubber was 4.68%, and the volume change rate did not exceed ±1%, indicating superior swelling resistance. In both actual well fluids and diesel oil, the maximum decreases in hardness were 8.7% and 9.5%, respectively. Tensile strength and elongation at break decreased with increasing immersion temperature, with elongation at break in 80 °C diesel oil decreasing by over 50%, indicating a significant decline in the tensile properties of the rubber. The average friction coefficient of rubber specimens immersed in actual well fluids at three temperatures, as well as in diesel oil at 25 and 50 °C, decreased compared with the high-acrylonitrile rubber without thermal expansion and swelling. However, the average friction coefficient of rubber specimens immersed in diesel oil at 80 °C increased. The wear quantity of the rubber increased following immersion in both media. Additionally, the friction coefficient and wear quantity of the rubber increased with increasing immersion temperatures. The results of the study can offer valuable insights into assessing the durability of properties in high-acrylonitrile stator rubber under complex well conditions.

Interface Interaction of Waste Rubber–Asphalt System

Asphalt pavement construction is a large-volume project, with the ability to recycle the industrial waste and reduce carbon emissions. Rubber-modified asphalt is a carbon-neutralized asphalt-based material, facilitating the recycling of waste rubber materials and improving the road performance of the asphalt mixture. To evaluate the interface interaction of the rubber–asphalt system and its effect on the viscosity characteristics of rubber-modified asphalt, the contact properties of rubber particles in asphalt were analyzed on a microscopic level. Rubber swelling tests and solvent elution tests were conducted on the rubber–asphalt system under different preparation conditions. The swelling ratio, degradation ratio, and swelling–degradation ratio were proposed to evaluate the interface interaction. The results show that the interface interaction of the rubber–asphalt system can be divided into the following three stages: swelling, effective degradation, and over-degradation. The degree of swelling is mainly affected by the content and size of the rubber particles and it is physically condensed, while the degradation is mainly affected by the preparation temperature and preparation time. The effective interface interaction greatly affects the viscosity with the building of the stable three-dimensional network structure. The stronger the interface interaction, the greater the viscosity of the rubber-modified asphalt, except for the 25% content of rubber particles. The gel film will be generated on the surface of the rubber particles throughout the swelling and effective degradation, increasing the viscosity of the rubber-modified asphalt.

Phase behavior of rubber and supercritical CO2: Operating parameters and swelling characteristics

AbstractThis study aims to compare the difference in the swelling process between styrene butadiene rubber (SBR) and natural rubber (NR) in ScCO2. A high‐pressure visual stainless‐steel autoclave was used to carry out swelling measurements based on the sample dimensions. The swelling rates for both rubbers followed a first‐order kinetic model. The diffusion coefficient for CO2 was determined from the change in the swelling degree with time. The shrinking process for the expanded rubber obeyed a second‐order kinetic model. A 2‐level full factorial experimental design was employed to discuss the influence of variables on rubber swelling and CO2 diffusion. Temperature and pressure were found to have a great influence on the equilibrium swelling degree, swelling rate and diffusion coefficient. For both SBR and NR, the maximum equilibrium swelling degrees were observed at 120°C and 20 MPa, yielding values of 1.18 and 1.16, respectively. The maximum diffusion coefficient reached approximately 3 × 10−9 m2 s−1 for both types of rubber at 120°C and 8 MPa. The crosslink density failed to affect these three responses, but the volume of expansion and the shrinkage rate were found to significantly decrease and increase, respectively, with increasing crosslink density. The motion of polymer segments forced by ScCO2 led to rearrangement of the material structure, which governed the nature of swelling, expansion, and shrinkage. Due to a lower number of entanglements and a weak electrostatic interaction exists between CO2 and the π‐system, SBR can absorb more CO2 and easily restructure than NR under the same conditions, resulting in higher equilibrium swelling degree, larger expansion and faster shrinkage than NR.Highlights Swelling of nature rubber and styrene‐butadiene rubber in ScCO2 is compared. Swelling degree is positively correlated with temperature and pressure. Diffusion coefficient increases with temperature but decreases with pressure. Swelling degree varies with rubber type, while CO2 diffusion dose not. Crosslink density significantly affects expansion and shrinkage of rubber.

Influence of Partially Carboxylated Powdered Lignocellulose from Oat Straw on Technological and Strength Properties of Water-Swelling Rubber.

The work is aimed at the development of an energy-saving technique involving the partial carboxylation of powdered lignocellulose products from the straw of annual agricultural plants and the use of the obtained products in rubber compositions as a water-swelling filler. Lignocellulose powder from oat straw (composition: α-cellulose-77.0%, lignin-3.8%, resins and fats-1.8%) was used for carboxylation without preliminary separation into components. Microwave radiation was used to activate the carboxylation process. This reduced the reaction time by 2-3 times. The synthesized products were analyzed by IR spectroscopy, thermogravimetry and scanning electron microscopy. Industrial product sodium carboxymethylcellulose (Na-CMC) was used as a swelling filler for comparison. The swelling fillers were fractionated by the sieve method; particles with the size of 0-1 mm were used for filling rubber compounds. The amount of swelling filler was 150 parts per 100 parts of rubber (phr). Due to the high filling of rubber compounds, plasticizer Oxal T-92 was added to the composition of a number of samples to facilitate the processing and uniform distribution of ingredients. The rubber composition was prepared in two stages. In the first stage, ingredients without swelling filler were mixed with rubber on a laboratory two-roll mill to create a base rubber compound (BRC). In the second stage, the BRC was mixed with the swelling filler in a closed laboratory plasti-corder rubber mixer, the Brabender Plasti-Corder® Lab-Station. Vulcanization was carried out at 160 °C. For the obtained samples, the physical-mechanical and sorption properties were determined. It has been shown that the carboxylated powdered lignocellulose from oat straw increases the strength properties of rubber in comparison with Na-CMC. It has been shown that when the carboxylated powdered lignocellulose from oat straw is introduced into the rubber composition, the degree of rubber swelling in aqueous solutions of various mineralizations increases by 50 and 100% in comparison with a noncarboxylated lignocellulose.

Swelling of rubbers of different chemical natures in supercritical carbon dioxide

Objectives. To investigate the swelling of the main types of rubbers used in the rubber industry in carbon dioxide in a supercritical state (SC-CO2), in order to assess the possibility of obtaining elastomeric materials with porous structures using fluid technology, based on them.Methods. The process of swelling of rubbers in SC-CO2 and subsequent foaming was carried out according to a specially developed technique using the original installation. This is a high-pressure apparatus with transparent windows, allowing for the use of an optical technique to directly measure the geometric dimensions of samples during swelling and foaming using a digital video camera. The study of the porous structure of foamed rubbers was carried out using scanning electron microscopy.Results. The study established experimental curves of the swelling kinetics in SC-CO2 of isoprene, butadiene, styrene butadiene, ethylene propylene, chloroprene, ethylene acrylate, siloxane, and organofluorine rubbers. The influence of temperature and pressure on the rate and equilibrium degree of swelling was studied. The diffusion coefficients of SC-CO2 in rubbers of various chemical natures were also determined.Conclusions. It was shown that the equilibrium swelling degree of rubbers in SC-CO2 depends on the chemical nature of rubbers. It does not correlate with the value of their solubility parameters, changes directly proportional to the diffusion coefficient and increases with increasing temperature and pressure. It was found that irrespective of the degree of swelling in SC-CO2, all the rubbers studied are intensively foamed at a sharp pressure drop. The size of the pores formed is tens of microns: significantly smaller than the size of pores formed when chemical pore formers are used.

Laboratory short-term aging of crumb rubber modified asphalt: RTFOT temperature optimization and performance investigation

Improper disposal of substantial scrap tires can result in significant environmental issues, such as air pollution, water resources, and soil contamination. The scrap tires can be turned into valuable materials by preparing tire rubber powder into Crumb rubber modified asphalt (CRMA). This method can effectively reduce environmental pollution and achieve the concept of energy conservation, environmental protection, and low-carbon. However, during the production process of CRMA mixtures, the elevated construction temperature may induce more severe short-term aging of the mixtures. The standard laboratory short-term aging scheme of asphalt binders, the Rolling Thin Film Oven Test (RTFOT), cannot simulate the short-term aging of CRMA due to the increase in construction temperature. Besides, the determination methods and indices of RTFOT aging temperature are still unclear and inconsistent. In this study, three CRMA binders were treated by RTFOT with five temperatures, and the short-term oven aging (STOA) protocol was conducted on CRMA mixtures with three types of gradations. Firstly, the chemical and rheological performance of CRMA binders and mixtures were investigated by conducting Gel permeation chromatography (GPC), Fourier transformation infrared spectroscopy (FTIR), Dynamic shear rheology (DSR) tests, and Bending beam rheometer (BBR) test. Then, the equivalent aging temperatures were determined to optimize RTFOT temperatures by comparing the chemical indicators of binders and mixtures. Finally, the correlations of chemical and rheological indices were established, and the rheological properties of aged asphalt in mixtures were predicted. The analysis results indicate that suitable RTFOT temperature is not only related to the technical routes and viscosity of CRMA binders, but also relevant to the mixture gradations. Binders with higher viscosity need elevated RTFOT temperatures from 173 °C to 193 °C, especially simulating short-term aging of mixtures with higher air voids. The swelling and degradation of crumb rubber contribute to the enhancement of the anti-aging performance. The aging index (AI) can reflect the anti-aging performance of CRMA binders, and the variation of AI can validate the rationality of the optimized RTFOT temperatures.

Methyl and Ethyl Ethers of Glycerol as Potential Green Low-Melting Technical Fluids.

The study is dedicated to the consideration of lower alkyl ethers of glycerol as potential components of low-melting technical fluids (e.g., heat transfer fluids, hydraulic fluids, aircraft de-icing fluids, etc.). Four isomeric mixtures of glycerol ethers (GMME-monomethyl; GDME-dimethyl; GMEE-monoethyl; GDEE-diethyl) were synthesized from epichlorohydrin and methanol/ethanol in the presence of sodium and subjected to detailed characterization as pure compounds and as aqueous solutions (30-90 vol%). The temperature and concentration dependencies of density, viscosity, cloud point, boiling range, specific heat capacity, thermal conductivity, and rubber swelling were obtained. On the basis of the data obtained, a comparison was made between the aqueous solutions of glycerol ethers and of other common bases for low-melting liquids (glycerol, ethylene glycol, and propylene glycol). Pure glycerol ethers could potentially be used as technical fluids in a very wide temperature range-from -114 to 150 °C. It was further demonstrated that in low temperature applications (e.g., in low-temperature chiller systems) the glycerol-ether-based aqueous heat transfer fluids could provide enhanced efficiency when compared to the glycerol- or propylene-glycol-based ones due to their lower viscosities and favorable environmental properties.

Swelling-degradation dynamic evolution behaviors of bio-modified rubberized asphalt under thermal conditions

The incorporation of bio-oil, derived from agricultural waste, as a partial substitute for asphalt, coupled with the modification of asphalt using crumb rubber from waste tires, synergistically enhances both sustainability and performance, resulting in bio-modified rubberized asphalt (BMR). Nevertheless, the properties of BMR are subject to fluctuations due to the interplay of crumb rubber swelling-degradation and asphalt aging, particularly under thermal conditions. This research delineates the temporal evolution of BMR's properties, with an emphasis on its rheological, chemical, and microscopic attributes. Three distinct phases were observed: initially, crumb rubber absorbed bio-oil, thereby swelling and augmenting high-temperature performance via the micro-skeletal effect. Subsequently, during the intermediate phase, rubber degradation manifested as macroscopic softening in the modified asphalt. Lastly, the aging of the asphalt resulted in hardening. The multi-stage properties of BMR are governed by the dynamic equilibrium between rubber swelling, degradation, and asphalt aging. These observations offer valuable insights for the quality control of BMR, thereby advancing waste reduction and recycling in downstream applications.

Performance evaluation and multiscale investigation of deodorant on mechanism of rubber modified asphalt

Asphalt fume emission caused by high-temperature is large during the production and construction of rubber modified asphalt, and the toxic and odor gas contained seriously pollutes the environment. This paper prepared rubber modified asphalt (RMA) and deodorant rubber modified asphalt (DRMA) and evaluated the impact of deodorants on the environmental and physical properties. Modern testing techniques, such as gel permeation chromatography, are used to explore the microscopic morphology of RMA, DRMA, and crumb rubber extracted from RMA and DRMA, so as to reveal the mechanism of deodorant in asphalt. Meanwhile, the effect of deodorant was monitored from macro scales by applying electrochemical sensing technology. The results show inhibiting the degradation of rubber in asphalt is the main mechanism of deodorant. Deodorant can not only promote the swelling of rubber in asphalt and improve the stability of sulfur elements, but also capture the odor particles in asphalt fume, reduce the concentration of polluting organic and H2S, realize the application of rubber modified asphalt environmentally-friendly, and promote the recycling of waste tires and the sustainability of pavements for pollution and carbon reduction.

Preparation of terminal blend/ grafting activated crumb rubber composite modified asphalt based on response surface methodology

Recycling waste tires, crushing them into crumb rubber (CR) and adding them to asphalt can effectively improve the performance and prolong the service life of asphalt pavement. However, the crumb rubber modified asphalt (CRMA) prepared by aforementioned process is prone to segregation during storage and transportation. The terminal blend rubber asphalt (TB) prepared with fine rubber powder by high-speed shearing at high temperature for long time, which effectively improves the storage stability and working performance of crumb rubber modified asphalt, but reduces the high-temperature performance. In this study, grafting activated crumb rubber (GACR) was incorporated into TB to improve its high temperature performance without impairing storage stability. Using shearing temperature, shearing time and grafting activated crumb rubber content as influencing factors, the response surface method (RSM) was carried out to optimize the preparation process. The results indicated that 180°C was a critical temperature, and the swelling of crumb rubber dominated with the temperature below it, but the desulfurization prevailed with the temperature above it. The extension of time favored the swelling of crumb rubber at low temperature but promoted desulfurization at high temperature. With the increase of crumb rubber content, the high temperature performance of modified asphalt improved whereas the storage stability deteriorated. According to the determination of response values and the prediction of optimal values, the suitable preparation conditions and parameters were recommended as shearing temperature of 190°C, shearing time of 90 min, and GACR content of 15%. The composite modified asphalt prepared through the optimized process showed good high temperature stability and storage stability.

Optimisation of the preparation procedure of crumb rubber modified bitumen with wax-based additives

Wax-based additives can be added to crumb rubber modified bitumen (CRMB) at different stages to enhance the workability. This study aims to optimize the preparation procedure by investigating the effects of the preparation procedure on the rheological properties of CRMB containing wax-based additives and the interaction mechanism. Rubber swelling tests under various conditions were conducted to examine the effects of temperature and additives on the interaction process. Rheological and thermal characterizations were performed on the CRMB binder and its liquid phase. Results show that reducing the bitumen viscosity by adding wax-based additives can promote the bitumen-rubber interaction and achieve similar swelling results at a lower temperature. However, a significant proportion of wax-based additives were found to penetrate rubber particles for the warm-produced CRMB. Although warm-produced CRMB may save energies compared to hot-produced CRMB, it is not recommended to replace the traditional hot-produced CRMB procedure.

Aging Potential and its Impact on the Bonding Strength of Rubberized RAP Asphalt Binder

Rejuvenating the reclaimed asphalt binder using crumb rubber-modified binder is a sustainable paving technology that has the advantage of using waste to recycle another waste material. As binder durability is crucial in evaluating the recyclability of reclaimed asphalt using crumb rubber-modified binder, this study investigates the binder potential for aging and the impact of aging on binder bond strength. Thirty binders with different crumb rubber and reclaimed asphalt dosages were aged by rolling thin oven and pressure aging vessel and tested by Fourier-transformed infrared spectroscopy and pull-off tests. The results reveal that binder aging and reclaimed binder addition strengthen the bonding strength and elevate the carbonyl intensity, which is the keen factor responsible for bonding enhancement. However, incorporating reclaimed binders attenuates the binder aging potential and limits the bonding enhancement after aging. Crumb rubber interacts with the asphalt binder and improves the bonding strength accordingly. However, the crumb rubber interaction with the binder significantly affects the aging potential of the binder, which increases with crumb rubber disintegration and decreases with rubber swelling. As rubber swelling is the dominating interaction mechanism, the crumb rubber modification mostly undermines the bonding enhancement after aging.

USE OF LIGNOCELLULOSE POWDERS AS SWELLING FILLERS FOR RUBBERS

Rubber sealing elements, which are limited in swelling in aqueous media, filling the space between the contacting surfaces, are widely used in the designs of packers in the oil and gas industry. The paper considers the use of porous lignocellulosic products as swelling fillers for rubbers with limited swelling. Lignocellulosic powder products are additives obtained by finely dispersed processing. Sodium carboxymethyl cellulose was used as a swelling polymer. Polycell 9B and lignocellulose powder from non-woody herbaceous plants. Some used cotton, flax or alfalfa. The mixing of basic rubber compound with swelling polymer was carried out in a closed rubber mixer of «Brabender» Company W50 E. Physicists conducted mechanical tests. The degree of swelling in various aqueous media was determined. The aim of the study is to obtain high-strength swelling rubbers based on powdered ligocellulose from herbaceous plants and to study their effect on the physical complex and mechanical properties of swelling rubbers based on nitrile rubber grade BNKS-28. It was found that the introduction of powdered lignocellulose from flax into the rubber composition allows maintaining the conditional tensile strength of rubber at the sample level without swelling filler, while the introduction of an industrial product of carboxylated cellulose sodium carboxymethylcellulose leads to a significant decrease in the strength of rubber. It is shown that the introduction of powdered lignocellulose from alfalfa makes it possible to increase the degree of swelling of rubbers in KOH solution compared with rubber filled with powdered lignocellulose from cotton and powdered lignocellulose from flax.

High hexane sorption capacity of loosely crosslinked PDMS rubbers at low temperatures: Macromolecular and physicochemical elucidation for VOC recovery

A series of soft polydimethylsiloxane (PDMS) rubbers was obtained by diluting reaction mixtures of a PDMS macromer and a crosslinker with an organic solvent. The degree of swelling of the softest rubber was 600 wt% when immersed in pure hexane at room temperature. From the Flory–Huggins equations, the free energy change for hexane sorption per 1 g rubber was calculated to be −7.4 J g−1 and the entropy contribution of the polymer chains was 1.6 J g−1 larger than that of the conventional PDMS rubber. The loosely crosslinked PDMS rubber could sorb 776 mg g−1 of hexane at 298 K and 606 mg g−1 at 195 K. The latter value was 4.4 times larger than that of the conventional PDMS rubber. At a low pressure of 23 Pa, the PDMS rubber sorbed a 3500-fold greater amount of hexane at 195 K, as compared with the value at 298 K. This high sorption amount is because the expansion energy of such soft PDMS rubber is small. The sorption heat of the loosely crosslinked PDMS rubber was 30.3 kJ mol−1 when calculated from the Clausius–Clapeyron equation. This value is substantially smaller than that of commercial activated carbon (75 kJ mol−1). Unlike activated carbon, PDMS rubber is insensitive to water and selectively sorbs VOCs even under a saturated humidity. Because of the large swelling potential and small sorption/desorption heat, the loosely crosslinked PDMS rubber will be an indispensable sorbent for the recovery of flammable gasses such as alkane and iso-alkane VOCs in the chemical and oil and gas industries.

Anisotropic swelling of rubber: extension of the Flory theory

The anisotropy of the swelling of rubber is examined both theoretically and experimentally. The Flory theory is extended to account for anisotropic swelling, allowing the determination of the average molecular weight between cross-links for rubber with swelling anisotropy for the first time. In addition, specimens from five commercial rubbers manufactured using either compression-moulding or sheet-rolling processes are swollen in appropriate organic solvents. Their linear dimensions and mass are carefully recorded before swelling, in the swollen state, and after drying, to obtain three linear swelling ratios which can differ by up to 10% within each specimen. Compression-moulded rubbers are shown to be transversely isotropic after moulding, whereas rolled rubbers exhibit full anisotropy, with different swelling ratios in all three directions. None of the rubbers examined were found to be truly isotropic. The new anisotropic swelling theory is applied to the experimental data to determine the average molecular weight between cross-links, which is determined as up to 0.5% larger than the value obtained using the Flory isotropic swelling theory.

Investigation of Physical and Mechanical Characteristics of Rubber Materials Exposed to High-Pressure Hydrogen.

Rubber materials play a key role in preventing hydrogen gas leakage in high-pressure hydrogen facilities. Therefore, it is necessary to investigate rubber materials exposed to high-pressure hydrogen to ensure operational safety. In this study, permeation, volume swelling, hydrogen content, and mechanical characteristics of acrylonitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), and fluorocarbon (FKM) samples exposed to pressures of 35 and 70 MPa were investigated. The results showed that the volume recovery and hydrogen desorption behavior of EPDM with the highest permeation were fast whereas those of FKM with the lowest permeation were slow. The volume of NBR with the highest hydrogen content expanded after decompression. In contrast, FKM swelled the most despite having the lowest hydrogen content. After exposure to high-pressure hydrogen, the compression set (CS) slightly increased due to internal cracks, but the tensile strength decreased significantly with increasing pressure despite the absence of cracks in the fracture area of all tensile specimens. It was concluded that the decrease in tensile strength is closely related to the volume increase because of the relationship between the relative true strength and the volume ratio.

High-quality ground tire rubber production from scrap tires by using supercritical carbon dioxide jet pulverization assisted with diphenyl disulfide

This study presents a high-quality ground tire rubber (GTR) production technology by using supercritical carbon dioxide jet pulverization. Diphenyl disulfide was incorporated as the devulcanization reagent during the pulverization process. The effects of rubber swelling on particle size distributions, shape characteristics, thermal degradation behaviors, and devulcanization behaviors of the acquired GTR were investigated. The results showed that fine pulverization of scrap tires can be achieved, along with a desired degree of rubber devulcanization. Rubber swelling or devulcanization was associated with the failure pattern of rubber under jet impact and was not beneficial for fine pulverization. Rubber devulcanization mechanisms included radical and oxidation-based reactions, both of which showed breakage selectivity of crosslinks. The excellent properties of the acquired GTR can help to achieve good dispersion and enhanced interfacial compatibility with the polymeric matrix. Therefore, supercritical carbon dioxide jet pulverization incorporated with diphenyl disulfide is a promising recycling technology for scrap tires.

The continuous swelling-degradation behaviors and chemo-rheological properties of waste crumb rubber modified bitumen considering the effect of rubber size

The chemo-rheological properties of crumb rubber modified bitumen are always unstable due to the mutable and uncontrollable swelling-degradation degree of crumb rubber in bitumen matrix. The study aimed at exploring the continuous swelling and degradation behaviors of crumb rubber modified bitumen (CRMB) considering the influence of rubber size through monitoring the dynamic viscosity changes of CRMB binders. Moreover, the synergistic effects of swelling-degradation degree and rubber size on the chemical and rheological properties of CRMB were investigated. The results revealed that the rubber size significantly influenced the swelling and degradation behaviors of CRMB. The reduction of rubber size shortened the equilibrium swelling and degradation time, while increased the related viscosity dramatically. Moreover, during the degradation process, the decrease of rubber size could accelerate the continuous swelling rate, increase the maximum viscosity and reduce the continuous swelling time of CRMB. Meanwhile, the high swelling degree and large rubber size were beneficial to enhance the high temperature properties, while the CRMB binder with high degradation degree showed the better low-temperature property, workability and wider Newtonian flow region. Furthermore, the degradation degree promoted the formation of free hydroxide groups, aldehydes, carboxylic acids and esters, while the swelling process increased the average molecular weight of whole liquid phase in CRMB binder. The outputs from this fundamental study are beneficial to provide the guidance to preparation conditions optimization of CRMB binders with different viscous property standards.

Investigating the role of swelling-degradation degree of crumb rubber on CR/SBS modified porous asphalt binder and mixture

Porous asphalt pavement is widely used due to its adequate water permeability, noise reduction and skid resistance. The study aims at exploring the potential of using the crumb rubber/styrene–butadienestyrene (CR/SBS) modified bitumen as high-viscosity binder for porous asphalt mixture, and investigating the effect of swelling and degradation degree of crumb rubber as well as SBS dosage on the performance of porous asphalt binder and mixture. The conventional, rheological and engineering properties of CR/SBS modified high-viscosity porous asphalt binders and mixtures were characterized. The results revealed that the CR swelling-degradation degree significantly affected the physical and viscoelastic properties of CR/SBS modified high-viscosity binders. With the swelling time prolonged, the viscosity of rubber bitumen enhanced gradually until reaching the equilibrium state, which kept falling during the degradation process dramatically. The full-swelling binders exhibited the highest complex modulus, zero-shear viscosity, rutting resistance, which deteriorated as the degradation degree increasing. However, the degradation of crumb rubber would be beneficial to improve the workability, thermal cracking resistance and deformation recovery ability of high-viscosity binder. Meanwhile, the incorporation of SBS copolymer could further strengthen both high-and-low temperatures viscoelastic performance of high-viscosity bitumen. In addition, the performance of porous asphalt with CR/SBS modified high-viscosity bitumen could meet the requirements of Marshall stability, air void content, Cantabro loss, run-off loss, anti-rutting, moisture damage resistance and permeability performance. Although the full-swelling asphalt mixture presented the best rutting resistance, it showed the poor adhesive and moisture damage resistance when compared with partial and full-degradation asphalt mixtures.

STUDY OF THE EFFECT OF DIOCTYL SEBACATE ON THE PROPERTIES OF EPICHLOROHYDRIN RUBBERS

The effect of different technologies for the introduction of a plasticizer - dioctyl sebacate on the properties of rubbers based on epichlorohydrin rubber of the Hydrin T-6000 brand was investigated. When using the technology of rubber swelling in a plasticizer, dioctyl sebacate exhibits a shielding effect, reducing the interaction of the filler-polymer, which leads to an improvement in low-temperature properties and a deterioration in the physical and mechanical properties of the material.