Polysulfide Rubber Research Articles

Effect of SiC nanoparticles on mechanical and damping properties of epoxy/polysulfide rubber blend composite

Blend polymer matrix composite material are becoming more and more popular due to their promising mechanical properties. In this research, blend polymer mixture was make from epoxy resin (EP) blended with different weight percentages of polysulfide rubber (PSR) (0, 3, 6, 10, 15, and 20%). Then tensile, impact, bending strength and damping ratio were evaluated to get the high quality of mechanical properties for the blend matrix. Due to the requirements to enhance the mechanical properties of this blend; a various weight fraction of carbide silica (SiC) nanoparticle was used as a reinforcement in the ratios of (0, 1, 3, and 5%) by weight to the best ratio of the blended matrix. Tensile, impact, bending and damping ratio tests were also conducted to get the best mechanical properties for the blend materials. Experimental results for the blend matrix showed that adding polysulfide rubber to epoxy resin resulted in a decrease in Young’s modulus, tensile strength, and bending strength; however damping ratio and the impact strength increased. It is found that the weight fraction of 6% of PSR is the Better case, which gave the better mechanical characteristics properties for mixture. Utility of this mixture; it has intermediates between flexible properties of a mixture at the highest rate of PSR and brittle mechanical properties for EP resin. Mechanical and damping properties showed an increasing when the carbide silica (SiC) with a weight fraction of 3% added, then it decreased slightly.

Elastomeric impression materials used in modern orthopedic dentistry

This article presents a review of elastomeric impression materials currently used in orthopedic dentistry. The elastomer group is divided into silicone, polyester, and thiocol (polysulfide) materials. Silicone impression materials are widely used in orthopedic dentistry. Their structural basis is polymethylsiloxane with active terminal hydroxyl groups. Polyester materials consist of the main and catalyst components (pastes). The main component contains a polymer with imine groups, fillers, and plasticizers. Sulfonic acid ester is present in the catalyst paste. When these two components are mixed, ionic (cationic) polymerization occurs. Polysulfide materials are produced as base and catalyst pastes. The structural unit of the main paste is polysulfide or mercaptan rubber, and the catalyst paste acts as an oxidizer. Lead dioxide is often used as an oxidizer. The resulting polymer does not have a stereoregular structure, which causes its stickiness. It is technologically challenging to obtain a polymer with a stereoregular structure.
 When theoretically comparing the listed types of elastomeric impression materials, according to their properties, chemical composition, advantages, and disadvantages, polyester and polysulfide impression materials can be distinguished as more advanced. Silicone materials have disadvantages; however, they are often used for domestic dentistry owing to the presence of domestic manufacturers and relatively low cost.

Synergistic Effect and Electrical Properties of Microporous Liquid Metal/Carbon Nanotube Polymer Sponge.

Sensing sponge materials with light weight, high elasticity, and electrical sensing properties are in enormous demand in electronic fields, but there is an imminent need to develop a scalable and facile method for the manufacture of the sensing material. Herein, an efficient in situ polymerization and convenient preparation process is reported to manufacture the microporous liquid metal/carbon nanotube-polysulfide rubber (LM/CNT-PSR) sponges with excellent mechanical and electrical properties, based on fluidic LMs and rigid CNTs with unique synergistic effect for sponge composites. Excellent mechanical properties of LM/CNT-PSR sponges, such as low density, excellent elasticity, remarkable mechanical recoverability, and self-healing property, are endowed by the interconnected microporous structure of sponge and flexible polysulfide rubber matrix with disulfide bonds. In addition, the synergistic effect of LMs and CNTs leads to excellent conductivity and unique electrical sensing property under mechanical pressure. Microporous LM/CNT-PSR sponges with high performance and simple fabrication process are promising sensing materials for various electronic devices, such as human motion monitoring, and weighing sensing.

Prediction on the Performance of Polymer-Based Mechanical Low-Pass Filters for High-G Accelerometers

A polymer-based mechanical low-pass filter(m-LPF) for high-g accelerometers makes it possible to remove high-frequency transient noises from acceleration signals, thus ensuring repeatable and reliable measurement on high-g acceleration. We establish a prediction model for performance of m-LPF by combining a fundamental vibration model with the fractional derivative standard linear solid(FD SLS) model describing the storage modulus and loss modulus of polymers. Here, the FD SLS model is modified to consider the effect of m-LPF shape factor (i.e., thickness) on storage modulus and loss modulus. The prediction accuracy is verified by comparing the displacement transmissibility(or cut-off frequency) estimated using our model with that measured from 3 kinds of polymers(polysulfide rubber(PSR), silicone rubber(SR), and polydimethylsiloxane(PDMS)). Our findings will contribute a significant growth of m-LPF for high-g accelerometers.

In Situ Incorporation of Liquid Polysulfide Oligomer Modified MoS2 into Polysulfide Rubber (PSR) as Solid Crosslinker with Greatly Improved Dispersion Ability and Interfacial Interaction

AbstractPolysulfide rubber (PSR) is a versatile sealing material, but suffers from poor mechanical properties, which can be solved by increasing the crosslinking density and introducing fillers. In this study, functionalized molybdenum disulfide (MMoS2) by in situ incorporation with different thiol‐containing compounds is obtained. On the basis of the optimum content of 0.5 wt.%, the performance of MMoS2/PSR is systematically studied. The results show that the interfacial interaction between MMoS2 and the matrix is improved. In particular, PSR reinforced by MoS2 modified with polysulfide oligomer (MoS2‐LPO) behaves the most excellently. Its solvent resistance and crosslink density are also improved by 14.2% and 39.4%, respectively. The storage modulus of MoS2‐LPO/PSR is 394% higher than that of the unmodified one. This is attributed to the MoS2‐LPO playing the role of filler and large‐sized solid crosslinker at the same time. Through broadband dielectric spectroscopy (BDS), it is determined that MoS2‐LPO/PSR has the longest relaxation time due to the stronger interfacial interaction. In order to understand the effect of interfacial interaction between MoS2 and PSR on the properties of the composites more clearly, MoS2 modified with other functional groups are also discussed.

Study on Modified Liquid Polysulfide Rubber Bimetallic Salt-Spray-Resistant Epoxy Coatings

In this study, liquid polysulfide rubber was modified by silane coupling agent. New kinds of anti-corrosion coatings with salt spray resistance and strong adhesion to the steel substrate were obtained using the modified liquid polysulfide rubber, bimetallic filler, carbon nanotubes, and epoxy resin. Infrared and nuclear magnetic resonance confirmed the preparation of new modified liquid polysulfide rubber through coupling reaction between the epoxy group of silane compound and the sulfide group of the liquid polysulfide rubber. A 1440 h neutral salt spray test showed the coating to be completely free of rust and blisters. The corrosion diffusion width of the scribed area was only 1.7 mm. In addition, in a 3.5% by weight NaCl solution, the coating shows no blistering and no corrosion phenomena compared with zinc-rich epoxy paints (the added zinc content was only 28.6%). These tests confirmed that the new coating had a dense microstructure, strong adhesion to the steel substrate, good corrosion resistance, and anti-blister performance. The performance indicates that the coatings have potential for use in the atmosphere and underwater, which provides a better choice for long-term protection of marine projects such as ships, wharves, offshore platforms, and wind power structures.

Viscoelastic behavior of glass fiber reinforced rubber-modified epoxy

Abstract Epoxies as a thermoset polymer have got a great attention in different applications. To elaborate their employing and surmount their brittleness, many polymers were blended with them. The results confirm that the good mechanical properties are obtained when 6wt% of Polysulfide Rubber (PSR) is blended with epoxy and reinforced with fiber glass. The effect of rubber and glass fiber on the viscoelastic properties of epoxy were investigated using creep-recovery data under different stress levels (5, 10, 15 and 20 MPa) and temperatures (30, 50, 70 and 90°C). Polysulfide addition caused larger creep and creep recovery. In addition, the creep resistance of glass fiber reinforced blend was significantly enhanced.

INFLUENCE OF DILUENTS AND PLASTICIZERS ON THE PROPERTIES OF EPOXY-POLYSULFIDE COMPOSITES

It was found that to increase the adhesive and physicomechanical properties of compositions based on epoxy resin and polysulfide rubber (thiokol), cured without heat treatment, it is necessary to carry out a preliminary thioetherification reaction (PRTE) due to the interaction of rubber mercaptan groups and oxirane cycles of epoxy resin at elevated temperatures and then use the product of this reaction to cure at room temperature. Composite materials based on the products of the thioetherification reaction significantly surpass analogs based on mechanical mixtures of epoxy resin and thiokol in terms of cohesive and adhesive strength, deformation capacity, fracture work, and specific impact strength. It is shown that the introduction of both diluents and plasticizers into the products of the preliminary thioetherification reaction of epoxy resins and polysulfide rubbers leads to an increase in the parameters of tensile strength and deformation capacity. The greatest strengthening effect is achieved with the use of oligoesteracrylate MGF-9 and glycidyl ether of diethylene glycol DEG-1, the smallest - with the introduction of the plasticizer EDOS. It was found that the introduction of plasticizers promotes some increase in the adhesive strength, but much less in comparison with the cohesive strength. In this case, the adhesion and cohesive characteristics change antibatically. It has been shown by dynamic mechanical spectrometry that the presence of diluents and plasticizers in epoxy-polysulfide composites leads to a decrease in the temperatures of the maximum values of the tangent of the angle of mechanical losses, loss modulus, the initial and final sections of the transition of the material from the glassy to the highly elastic state, as well as the density of the chemical network in the epoxy matrix.

Study of Mechanical Properties and Thermal Conductivity of Polymeric Blend [Epoxy and polysulfide rubber (EP + PSR)] Reinforced by Nano Ceramic Powder ZrO2

A polymeric blend nanocomposites were prepared using mixer of Epoxy and polysulfide rubber [EP+PSR] as a matrix material and the Zirconium Oxide Nano-powder ZrO2 as a reinforcement material, in different particle sizes and same adding ratio of 2% wt . Hand Lay-up molding method was used to prepare the samples. Impact strength, compression resistance and thermal conductivity tests, were carried out for the polymeric blend and composites samples before and after immersion in tap water. The results showed that adding Nano zirconia powder to the polymer blend improved the mechanical properties, while the thermal conductivity of the polymer blend was higher than that of the composites. Also, it was observed that water immersion caused a decrease in impact strength, compression resistance, modulus of elasticity and thermal conductivity in a manner proportional to the immersion time.

Analysis of the Impact on the Mechanical Properties of Modification of Oligohydroxyethers in Organic Solvent Solution with Rubbers.

This paper proposes and presents the chemical modification of linear hydroxyethers (LHE) with different molecular weights (380, 640, and 1830 g/mol) with the addition of three types of rubbers (polysulfide rubber (PSR), polychloroprene rubber (PCR), and styrene-butadiene rubber (SBR)). The main purpose of choosing this type of modification and the materials used was the possibility to use it in industrial settings. The modification process was conducted for a very wide range of modifier additions (rubber) per 100 g LHE. The materials obtained in the study were subjected to strength tests in order to determine the effect of the modification on functional properties. Mechanical properties of the modified materials were improved after the application of the modifier (rubber) to polyhydroxyether (up to certain modifier content). The most favorable changes in the tested materials were registered in the modification of LHE-1830 with PSR. In the case of LHE-380 and LHE-640 modified in cyclohexanol (CH) and chloroform (CF) solutions, an increase in the values of the tested properties was also obtained, but to a lesser extent than for LHE-1830. The largest changes were registered for LHE-1830 with PSR in CH solution: from 12.1 to 15.3 MPa for compressive strength tests, from 0.8 to 1.5 MPa for tensile testing, from 0.8 to 14.7 MPa for shear strength, and from 1% to 6.5% for the maximum elongation. The analysis of the available literature showed that the modification proposed by the authors has not yet been presented in any previous scientific paper.

3D Graphene – sponge skeleton reinforced polysulfide rubber nanocomposites with improved electrical and thermal conductivity

As high performance sealants, polysulfide rubbers (PSR) have been extensive used to seal the tanks of aircraft fuel. Disappointingly, it is easy to produce static electricity due to the movement of fuel, resulting in security issue. In this work, a three-dimensional (3D) RGO-PU foam was constructed by using PU sponge as a template and GO together through hydrothermal reduction. Then the polysulfide rubber composites (RGO-PU/PSR) were fabricated by impregnating 3D RGO-PU framework with liquid polysulfide oligomers (LPO) under vacuum assistance, following by heat treatment. The RGO-PU/PSR composites exhibited improved conductive properties than neat PSR. For example, the volume resistivity of the 0.5 wt%-RGO-PU/PSR composites was 2.6 × 106 Ω·cm, which had a conspicuous 5 orders of magnitude decrease compared to neat PSR. The thermal conductivity of RGO-PU/PSR composite was also enhanced to 0.598 W/(m.k), which raised about 153% compared to the value for neat PSR. It was because that the introduction of 3D RGO-PU foam provided a path for electronic transmission and phonons transfer. In addition, the dielectric properties demonstrated that RGO-PU/PSR composites showed a higher dielectric constant than neat PSR. Furthermore, the polysulfide rubber composites also showed greatly improved compression strength and Young’s Modulus.

Effect of Technological Factors on some Properties of Composite tube with Epoxy Resin K-153 Matrix

The tube is made of polymer composite material based on K-153 epoxy resin (K-153 epoxy resin is made from ED-20 epoxy resin modified by thiokol and oligomer acrylate), T-13 glassfiber, hardener polyethylenepolyaminemade by wrapping on machine. The effect of drying temperature on mechanical properties (tensile strength, flexural strength) of polymercomposite materialwas studied. The paper also mentions to select suitable hardener to beused for polymercomposite tube wrapping. The results show that the strength at break, flexural strength of polymercomposite material are changedmuch when changing wrapping angle. The drying temperature increases, the curing time of polymercomposite material is much reduced. The time to stabilize after drying also greatly affects the pressure resistance of polymer composite tubes.
 Keywords
 Polymercomposite, K-153, tensile strength, flexural strength, pressure resistance.
 References
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One Step Synthesis of One Dimensional Nano MnO2 and Their Application as Oxidizing Agent for Polysulfide Polymers

In this work, MnO2 nanowires and nanorods have been prepared via a simple hydrothermal reaction. The morphology of MnO2 can be easily controlled by the change of the mole ratio of Mn7+ to Mn2+. And the obtained products are well characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), the high-resolution TEM (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectrometer (XPS), etc. The obtained MnO2 samples are employed as the curing agent for polysulfide sealant. The maximum torque of the polysulfide polymer cured by MnO2 nanowires is the highest. The performances are verified by rheological tests of the curing profile, mechanical analysis, and tensile strength tests. The results demonstrate that both of the nanowires and nanorods have excellent vulcanization effects and reinforcing effects in comparison with commercial MnO2. The surface area, structure, and morphology of MnO2 are used to analyze the possible reasons for their promising application in vulcanizing agents for polysulfide rubber.

Convenient preparation of flexible polysulfide rubber chain-bridged polybenzoxazine

In this work, a benzoxazine bridged by a flexible polysulfide rubber chain (BLP) was conveniently prepared through the ring-opening addition of thiol-capped liquid polysulfide rubber (LP-3) and bisphenol-A/aniline-based benzoxazine (B-a). The structure and composition of BLP were investigated by nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectra, and the structure and properties of polymerized BLP (PBLP) were characterized by FT-IR, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). BLP was a highly viscous fluid at room temperature with a low curing temperature. After curing, most of the polysulfide chains were incorporated into the crosslinked PBLP through covalent bond linkages. PBLP presented excellent flexibility, outstanding thermal stability, and an extremely high char yield. The glass transition temperature (Tg) of PBLP was 80 °C, the 5% weight-loss temperature (T5%) was 270 °C, and the char yield at 800 °C was 33%. Benzoxazine bridged by a flexible polysulfide rubber chain (BLP) was conveniently prepared through the ring-opening addition of thiol-capped liquid polysulfide rubber (LP-3) and bisphenol-A/aniline-based benzoxazine (B-a). BLP was a highly viscous fluid at room temperature with a low curing temperature. After curing, the polymerized BLP (PBLP) presented excellent flexibility, outstanding thermal stability, and an extremely high char yield.

Mechanical properties of a hybrid composite material (epoxy-polysulfide rubber) reinforced with fibres

This study investigated the mechanical properties of a hybrid polymer matrix composite material (PMCs) prepared from 98 wt% epoxy resin and 2 wt% polysulfide rubber reinforced with two types of fibres, glass fibres and carbon fibres, which were used in the form of a plain woven material with a volumetric fracture of 20%. Mechanical tests were conducted for the composite materials before and after reinforcement with these fibres to ascertain the effect of adding fibres on the mechanical properties of the composite material. The fibre effect was evident in improving all studied properties, especially tensile strength and impact strength.

Synthesis, characterization, and kinetic study of activated carbon modified by polysulfide rubber coating for aqueous hexavalent chromium removal

Activated carbon (AC) is a widely used adsorbent with a limited selectivity for chromium species. In this study, polysulfide rubber (PSR) polymer was synthesized, characterized by FTIR, and coated on F400 granular AC to obtain AC-PSR. The material properties of this composite adsorbent were investigated using SEM, TEM, EDS, TGA, BET isotherm, and XPS. The effectiveness of AC-PSR for aqueous Cr(VI) removal was investigated, and compared against virgin AC. The results showed that despite a 23% decrease in the surface area of AC after PSR coating, AC-PSR had a higher capacity for Cr(VI) adsorption. Adsorption followed a pseudo-second-order biphasic diffusion model for both AC and AC-PSR. The reaction rate constants showed that despite faster initial kinetics between AC and Cr(VI) during the film diffusion step, AC-PSR exhibited faster kinetics during the intraparticle diffusion step. The Langmuir isotherm model was found to be the best model to describe the experimental data, which showed a higher adsorption capacity for AC-PSR (QM,AC=3.472mg/g vs. QM,AC-PSR=8.929mg/g) and a stronger binding between Cr(VI) and AC-PSR (bA,AC=0.391L/mg vs. bA,AC-PSR=0.696L/mg). Regenerated AC-PSR showed an 8% increase in Cr(VI) removal efficiency after the first cycle, and then maintained a ∼98% Cr(VI) removal for three additional successive cycles.

The effects of polyester fiber and polysulfide rubber content for the mechanics performance of polymer resin concrete

In order to analysis the polymer mortar performance, with different polyester and polysulfide content polymer mortar specimens by compression tests, bending tests, scanning electron microscopy method, test results indicate that: the flexural strength, compressive strength and the ratio of bending pressure were improved when the content of polyester fiber was 0.8% and the content of polysulfide rubber was 1.0% and without the addition of these two substances. However, when 0.8% of the polyester and polysulfide cement dosage compared to 1.0%, flexural strength of polymer mortar increased 3.0%, compressive strength decreased 4.0%.

Toughening of Epoxy Polysulfide Binary Blend Composite

In a composite structure, it is anticipated that high toughening can be achieved by taking advantage of mixing rubber with epoxy. The purpose of this paper is to investigate the toughness characteristics of Polymeric Composites containing Polysulfide Rubber (PSR) as a toughener to a brittle base epoxy resin. Through comparing with neat resin specimens (epoxy, epoxy +PSR), the results showed that the addition of PSR into polymeric resin enhance toughness of epoxy. Similarly experiment showed that the maximum value of mixing ration is 6% PSR, which cause a noticeable enhancement in composite strain, but a reduction in tensile strength and modulus of elasticity at fracture.

Effect of Carbon Nanotube on Damping Characteristic of Epoxy Polysulfide Blend Composite

In a Nano-composite structure, it is anticipated that high damping can be achieved by taking advantage of the interfacial friction between the nanotubes and the polymer. The purpose of this paper is to investigate the structural damping characteristics of polymeric composites containing Carbon nanotubes (CNTs) with various amounts with polysulfide rubber (PSR) . The damping characteristics of the specimens with 0 wt% and 0.6 wt% Carbon nanotube contents were computed experimentally. Through comparing with neat resin specimens (epoxy, epoxy +PSR), the study showed that one can enhance damping by adding CNTs fillers into polymeric resins. Similarly experiment showed that the maximum value of damping ratio was obtained at 0.4 wt% CNTs.

Nghiên cứu chế tạo lớp phủ bảo vệ bo mạch điện tử trên cơ sở nhựa Epoxy biến tính bằng cao su Polysulfide lỏng

This paper presents some results in studying and producing a coating to protect printed circuit board from tropical environmental impact. We have tested the protective ability of the coating based on epoxy resin ED-20 and low-molecular weight polyamide resin L-20 modified by liquid polysulfide rubber NVB-2. The testing data has shown that the coating has high mechanical, environmental and electrical durability.