Reactive Rubber Research Articles

CHARACTERIZATION OF ASPHALT MODIFICATION USING GROUND RUBBER AND REACTIVE RUBBER NR-g-MA AS COMPATIBILIZER

This study aims to improve the quality of asphalt by adding ground tyre rubber (GR) and reactive rubber (NR-g-MA) as compatibilizers of asphalt-rubber mixability. The use of GR has been widely used to improve the performance of asphalt and extend the service life of asphalt. The NR-g-MA used was the product of the copolymerization of SIR-20 rubber grafts with maleic anhydrous (MA) through a melting process in an internal mixer. Mixing of GR in asphalt was carried out in an external mixer with composition of asphalt/GR 95/5 phr at the temperature of 180oC for 90 minutes. The performance of asphalts were measured based on conventional test of penetration and softening point. The rheological properties of asphalt were measured using a Dynamic Shear Rheometer (DSR). Important parameters of the rheological properties measured are complex shear modulus (G*) and phase angle (d). Asphalt resistance to the permanent deformation (rutting) were determined on asphalt that has undergone a short-term aging process in a rolling thin film oven (RTFO) and measured at high temperatures (58-82OC). Fatigue crack resistance was tested on asphalt that has undergone a long-term aging process using the method of pressure aging vessel (PAV) and measured at low temperatures (25-31OC). Asphalt-GR mixtures' chemical, thermal and morphological properties were studied using ATR-FTIR, DSC/TGA, and SEM respectively. The results showed that adding used ground rubber (GR) decreased the penetration value by 9.93 – 18.87% and increased the softening point of asphalt from 5.57 – 11.40%. Rheological analysis showed that the addition of GR and compatibilizer NR-g-MA increase the value of complex shear modulus (G*) and decrease the phase angle (d) of the asphalt. The addition of ground rubber and reactive rubber of NR-g-MA to asphalt improve the performance of asphalt because it has rutting resistance at high temperatures as well as improves asphalt cracking resistance at low-temperature measurements. The addition of NR-g-MA reactive rubber to modified asphalt ground rubber can increase the mixability of asphalt-rubber used tires.

Dynamic heterogeneity and nanophase separation in rubber-toughened amine-cured highly cross-linked polymer networks

Solid state nuclear magnetic resonance (NMR) spectroscopy and small-to wide-angle X-ray scattering (SWAXS) methods were used to characterize the heterogeneous dynamics and polymer domain structure in rubber modified thermoset materials containing the diglycidyl ether of bisphenol A (DGEBA) epoxy resin and a mixture of Jeffamine reactive rubber and 4,4-diaminodicyclohexylmethane (PACM) amine curing agent. The polymer chain dynamics and morphologies as a function of the PACM/Jeffamine ratio were determined. Using dipolar-filtered NMR experiments, the resulting networks are shown to be composed of mobile and rigid regions that are separated on nanometer length scales, along with a dynamically immobilized interface region. Proton NMR spin diffusion experiments measured the dimensions of the mobile phase to range between 9 and 66 nm and varied with the relative PACM concentration. Solid state 13C magic angle spinning NMR experiments show that the highly mobile phase is composed entirely of the dynamically flexible polyether chains of the Jeffamine rubber, the immobilized interface region is a mixture of DGEBA, PACM, and the Jeffamine rubber, with the PACM cross-linked to DGEBA predominantly residing in the rigid phase. The SWAXS results showed compositional nanophase separation spanning the 11–77 nm range. These measurements of the nanoscale compositional and dynamic heterogeneity provide molecular level insight into the very broad and controllable glass transition temperature distributions observed for these highly cross-linked polymer networks.

Mode II fracture characterization of toughened epoxy resin composites

Epoxy resin used commonly as a matrix for polymer composite materials has good handling properties, but is too brittle. That is why various modifiers are used to increase the flexibility of products based on epoxy resin. This leads to two issues: how to efficiently increase the toughness of the resin without impacting significantly other properties, as well as how to measure the toughness in composite materials. The work aimed to show how the addition of a reactive rubber modifier will affect the fracture toughness of the obtained laminates during the longitudinal shear test (Mode II fracture). In total, three epoxy-glass laminates with different matrices were made and subjected to the End-Notched Flexure test according to ASTM D7905/D7905M standard: (1) the basic matrix of Epidian 6 resin, (2) Epidian 6 modified with the addition of 10% of Albipox 1000 reactive liquid rubber and (3) Epidian 6 modified with the addition of 10% of Hypro 1300X16 ATBN reactive liquid rubber. Based on the obtained results, it can be seen that the modulus of elasticity for the modified laminates was decreased compared to the laminate of pure epoxy resin (by ~ 25%). However, the addition of reactive rubbers increased the fracture toughness of the modified epoxy-glass laminates in the Mode II longitudinal shear test (GIIc) by ~ 40–60%. Thus the benefits of modification outweigh the drawbacks if fracture toughness is an important designing consideration in a given application. The applicability of ENF method is successfully tested, but potential drawbacks are indicated—careful control of specimen thickness is necessary.

Effects of core–shell and reactive liquid rubbers incorporation on practical adhesion and fracture energy of epoxy adhesives

Effects of core–shell and reactive liquid rubbers incorporation on practical adhesion and fracture energy of epoxy adhesives

Vulcanization behavior and mechanical properties of isoprene-modified silica reinforced butyl rubber composites

Butyl rubber was reinforced by the isoprene-modified silica. The modified silica was prepared via chemical modification by a hydrophobic and reactive oligomeric liquid isoprene rubber in a solvent. Thereafter butyl rubber was compounded with the modified silica and vulcanized by thermal compression molding process. Their properties were studied using oscillating disk rheometer (ODR), differential scanning calorimeter (DSC), dynamic mechanical analyzer (DMA), and universal testing machine (UTM). The surface modification of the silica moved up the curing time and enhanced apparently tensile strength and modulus of the rubber composites. In conclusion, cure behavior and mechanical properties of butyl rubber/silica composites can be controlled by chemical modification of the silica surface using rubber molecules.

Toughness improvement of novel biobased aromatic polyamide/SEBS/organoclay ternary hybrids

ABSTRACTBiobased aromatic polyamide/organoclay (Cloisite30B, C30B) nanocomposites were melt‐compounded with reactive and nonreactive styrene–ethylene–butylene–styrene (SEBS) rubbers at different weight contents to form ternary and quaternary blends. The mechanical properties were investigated as a function of the blend composition. The elongation at break and the impact strength increase with increasing SEBS rubber content, whereas the Young's modulus logically decreases proportionally to SEBS amount. Extra addition of SEBS grafted maleic anhydride (SEBS‐g‐MA) induces a synergistic effect. The SEBS‐g‐MA makes it possible to limit the aforementioned rigidity loss and to greatly increase the impact strength. The critical strain energy release rate increases significantly when both reactive and nonreactive rubbers are combined. Three types of microstructures appear depending on the blend composition: (1) small and numerous well‐dispersed particles when reactive rubber is used, (2) about 10 times bigger and less numerous well‐dispersed particles in the case of nonreactive rubber, and (3) a flocculated dispersion of small particles when both reactive and nonreactive rubber are added. Finally, the polyamide performances were significantly increased when the flocculated morphology was noticed due to a better PAXD/SEBS interfacial adhesion given by the SEBS‐g‐MA compatibilization and to a thinner rubber distribution in the matrix. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48888.

Flexible epoxy composite coatings modified by reactive rubber with improvements in water and corrosive resistances

Abstract Epoxy composites were modified by reactive polybutadiene, and their resistance to T-bend and liquid permeation was evaluated to develop flexible epoxy composite coatings with good resistance to corrosive media. The composites’ resistance to bending on galvanic sheets was improved with the addition of up to around 15 wt.% amino liquid polybutadiene (ALPB) as reflected by the cross-section images after bending tests and bending times at break. The initial impedance increased with the addition of up to 15 wt.% ALPB in the composites, whereas the resistance reduced in a much slow rate with immersion time for the sample containing ALPB at around 10 wt.%. This result suggested that their resisting ability depended on the amount and dispersion of ALPB. The Rc and Cc parameters from the electrochemical impedance spectroscopy measurements revealed that the improvement in resistance to electrolyte resulted from the compactness increment at certain range of ALPB additions, which was also supported by their water uptake trends. Moreover, the addition of ALPB above 20% resulted in severe aggregations and phase separations. The resulting reduced compactness reflects the fact that the excessive reactive rubber addition leads to the negative effects on their resisting ability upon both T-bend and liquid permeation.

Surface Activation of Wood Plastic Composites (WPC) for Enhanced Adhesion with Epoxy Coating

Abstract This work aims to improve the adhesive force of epoxy coating with a wood-plastic composite (WPC) surface. First, WPC was formulated using the extrusion technique through different percentages of wood flour (WF) with virgin polyethylene (PE) in the presence of a coupling agent. Dynamic mechanical analysis and water percentage gain (WPG%) were performed to find the optimized WF/PE mixing ratio. The optimized formula was subjected to surface treatment by different methods, including chromic acid oxidation, ultraviolet irradiation, and flame and heat treatment. Then the treated surface of WPC was coated with nano-modified epoxy resin using carboxylated carbon nanotube, organically modified nanoclay (Cloisite-30B), and reactive rubber nanoparticles. The surface treatment of the WPC was characterized with contact angle measurement and Fourier Transform Infrared (FTIR), while the interaction between the WPC and epoxy coat was investigated by attenuated total reflection FTIR microscopy analysis. The adhesion strength of the nano-modified epoxy showed significant enhancement when investigated by pull-off method and cross-cut test. Nano-scratching was utilized in exploring the effect of different surface treatments on enhancing adhesion to epoxy. The interfacial morphological behavior of epoxy coating on the WPC surface was investigated by Scanning Electron Microscope. The results indicated that chemical treatments helped for the functionalization of the WPC surface, leading to stronger adhesion with epoxy. These epoxy-coated WPC composites recorded enhanced mechanical properties because of the chemical reaction between the WPC surface and epoxy.

Amphiphilic Janus nanosheets by grafting reactive rubber brushes for reinforced rubber materials

An amphiphilic Janus nanosheet with different reactive rubber brushes on two opposite sides can simultaneously strengthen and toughen rubber blends.

Enhancement of Recycled WPC With Epoxy Nanocomposite Coats

THE RECYCLED plastic and wood waste were recycled to produce new useful product, wood plastic composite (WPC), that having characteristics close to commercial wood. WPC was performed by compounding and forming different recycled polyethylene/wood flour (PE/WF) weight ratios as 70/30, 60/40, 50/50 and 40/60 using twin screw extruder. Based on the mechanical properties measured via dynamic mechanical analysis (DMA), an optimized ratio was found to be (50/50)and was chemically treated with chromic acid solution and investigated by FTIR that approved successful functionalization after treatment. The treated WPC was then coated with different epoxy nanocomposites including reactive rubber nanoparticles (RRNP), montmorillonite nanoclay (MMT) and carbon nanotubes (CNTs). The coated WPC was fully tested using mechanical characterizations (modulus and scratch), water absorption (dist. and sea water), and thermal gravimetric analysis (TGA). The results showed that WPC coated with epoxy/CNT, epoxy/MMT and epoxy/RRNP has an enhanced final product with promising mechanical and physical properties compared to blank or uncoated WPC specimens. Also WPC coated with all epoxy nanocomposites has got enhanced modulus, more scratch resistance, lower water absorption and developed thermal stability, compared to the un-filled epoxy coat. Of those, the epoxy-CNT nanocomposite is an optimized protective coat for WPC even after immersion in water with different conditions.

Study on the adhesive properties of reactive liquid rubber toughened epoxy-clay hybrid nanocomposites

Abstract The present work investigates the adhesive properties and morphology of diglycidyl ether of bisphenol A nanocomposites modified with reactive butadiene acrylonitrile copolymers having different amine equivalent weight. Tensile adhesive strength and shear adhesive strength of epoxy resin were significantly increased due to reactive rubbers and nanoparticles (ZW1) incorporation to the epoxy matrix. Hybrid composites based on 1 wt% ZW1 and 10 wt% ATBN-16, 1 wt% ZW1 and 15 wt% ATBN-21 exhibited maximum adhesive strength in comparison with neat epoxy resin as well as epoxy nanocomposite containing 1% ZW1. Tensile adhesive strength of hybrid composites containing 1% ZW1 and 10% ATBN-16 as well as 1% ZW1 and 15% ATBN-21 was maximally enhanced. The fracture surfaces of epoxy hybrid composites showed significant plastic yielding together with delaminated and stratified structures, explaining thus the increase of the adhesive strength of tested composites. This finding was confirmed by FTIR spectra in terms of chemical reactions occurrence between the reactive rubbers and epoxy matrix.

Improving of Temperature Susceptibility of Asphalt 60/70 using Synthesized Reactive Rubber Nanoparticles for use in Different Climate

The use of reactive polymers as modifiers for asphalt appears promising. Asphalt penetration grade 60/70 cannot be used in coating applications for its long drying time at ordinary temperature and for its brittleness at very cold temperature. This material is very cheap as compared to blown asphalt that usually used in industrial applications. This study aims to use reactive polymers in modification of soft asphalt to produce very specific asphaltic material for use in infrastructure applications especially coating instead of highly expensive materials. The new asphaltic material is low cost and has high quality performance at low temperature. To achieve the aim of study, RRNP was used as additive to modify asphalt in percentages of 3, 5, 7 and 10% w/w. The prepared RRNP was then tested for their particles size using DLS and TEM, SEM, 1HNMR. RRNP was used to modify the thermo mechanical properties of asphalt via forming chemical bond, and the changing in mechanical and thermal properties of the mixes as well as the storage stability were studied. Also, the morphology (SEM), thermal characterization (TGA), Dynamic mechanical analysis (DMA), rheological tests, while, the prepared coatings were applied to carbon steel panel and tested for bending, Abarsion test and impact test were detected. Overall, the results show that the chosen modifiers are the best so far in the modification of soft asphalt to suit the industrial applications in different climate conditions.

Synthesis and characterization of phenol/formaldehyde nanocomposites: Studying the effect of incorporating reactive rubber nanoparticles or Cloisite-30B nanoclay on the mechanical properties, morphology and thermal stability

In this work, phenol/formaldehyde nanocomposites were synthesized using reactive rubber nanoparticles (RRNP) and cloisite30B nanoclay with different percentages and were fully investigated. A little amount of these nanomaterials enhanced the mechanical properties of the produced composites. This enhancement is attributed to the interaction of these nanomaterials with the bakelite matrix. In bakelite/RRNP, the mechanical properties enhancement is due to the chemical connection of RRNP to the bakelite matrix while in bakelite/Cloisite30B, this enhancement is due to polar/polar interaction. It was observed that the composites exhibited an intercalated disordered structure by means of Xray diffraction (XRD) and transmission electronic microscopy. The crosslinking density of the bakelite network was greatly influenced by the presence and type of nanomaterial that was added to the resin. The thermal stability was investigated with TGA/DSC which proved that these nanocomposite are (10–20)% more thermally stable than neat Bakelite resin.

Morphology and mechanical properties of PA6/organoclay nanocomposites toughened by bulk rubber and core-shell rubber

Reactive bulk rubber (EOR-g-MA) and reactive core-shell rubber (ABS-g-MA) are selected as toughening agents to toughen PA6 nanocomposites. The two blends are designed with 20 wt-% rubber phase and 3 wt-% organoclay. X-ray diffraction, transmission electron microscopy and scanning electron microscopy were used to evaluate the degree of exfoliation of organoclays and morphology of the nanocomposites. The organoclay platelets are well exfoliated in the nanocomposites. At the same time, the size of the elastomer particles and interfacial adhesion between polyamide 6 and elastomers are dramatically affected by the existence of organoclay. ABS-g-MA is found to promote the toughness efficiency of PA6 than does EOR-g-MA, which reveals higher impact strength and elongation at break. However, tensile strength and Young's modulus of PA6 blends based on EOR-g-MA elastomer are higher than those based on ABS-g-MA elastomer.

Preparation and characterization of reactive liquid rubbers toughened epoxy-clay hybrid nanocomposites

Abstract The present work investigates the effect of organomodified nanoclay (ZW1) and butadiene-acrylonitrile copolymer terminated with different amine groups (amine-terminated butadiene-acrylonitrile, ATBN) on the properties and morphology of epoxy resin. The morphologies of the nanocomposites were analyzed by X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The nanocomposites structure was confirmed by Fourier transform infrared (FTIR) spectroscopy, XRD and TEM. The properties evaluation showed that the polymeric modifier and nanoclays strongly influence the fracture toughness and flexural properties of the nanocomposites. Hybrid epoxy composites containing 1% ZW1 and ATBN rubbers showed improved fracture toughness and flexural properties in comparison with unmodified epoxy resin. FTIR spectra showed an increase in the hydroxyl peak height peak height of 3360 cm-1 due to reactive rubber incorporation. SEM micrographs of hybrid epoxy resin nanocomposites showed significant plastic yielding of the polymer matrix with stratified structures and more cavitations, explaining thus the enhancement of fracture toughness and flexural strength of the nanocomposites.

Functionalized liquid natural rubber and liquid epoxidized natural rubber: A promising green toughening agent for polyester

ABSTRACTToughened unsaturated polyester resins (UPRs) were prepared using two different reactive rubbers, namely, liquid natural rubber (LNR) and liquid epoxidized natural rubber (LENR). The effect of varying amounts of LNR and LENR on the morphology, thermal, and mechanical properties of UPR were evaluated. Fourier Transform Infrared spectroscopy was used to investigate the probable crosslinking reaction and changes in the functional groups on crosslinking. Field emission scanning electron microscopy and infinite focus microscopy were used to study the morphology of fracture surfaces. Tensile test showed that both the rubber‐modified resins (1.5 wt %) improved tensile strength. The viscoelastic properties and thermal stability of the toughened polyesters were evaluated using dynamic mechanical thermal analysis and thermogravimetric analysis, respectively. A slight reduction in the glass transition temperature (Tg) of the polyester was reported on the addition of both the rubbers. An increment in impact strength and fracture toughness was observed at 1.5 wt % for LNR and 4.5 wt % for LENR‐modified UPR. The results showed that both the liquid rubbers improved the mechanical properties of UPR. However, LENR‐modified UPR exhibited a more significant improvement in the mechanical properties compared to LNR‐modified UPR. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41292.

Research Progress on Reinforced Concrete Composite Beam in China

Reinforced concrete composite beam plays a very important role in the precast concrete structure, composite beam research is critical. Based on the research results about it in China, on the one hand, from the traditional composite beams to the improved ones, the various kinds of composite beams were concluded; on the other hand, the applications of new building materials in the composite beams had been included, which included fiber reinforced cement-based composites, steel fiber reinforced concrete, reactive powder concrete and crumb rubber concrete. Through to the both related tests and theoretical studies, the progress of the composite beams was summarized. Finally, the further research was prospected.

Localization of carbon nanotubes in polyamide 6 blends with non-reactive and reactive rubber

Blending of two immiscible polymer matrices can be an effective way to combine favourable properties of both blend partners. The additional incorporation of multiwalled carbon nanotubes (MWCNTs) in such thermoplastic blends may further enhance the blend properties and especially generate electrical conductivity.In the present study, 20 wt.% of non-reactive rubber and maleic anhydride functionalized rubber were melt blended with polyamide 6 and 3 wt.% MWCNTs by using different incorporation strategies. For the blends containing non-reactive rubber, the MWCNTs were always localized selectively in the thermodynamically preferred polyamide phase as shown by TEM images and electrical measurements. Interestingly, the different strategies resulted in different localization behaviours of the MWCNTs in case of the reactive rubber. These findings demonstrate the significant influence of maleic anhydride groups of the rubber component on localization of MWCNTs in the different blend phases which results in different values of electrical volume resistivity of the blends.

Swellable elastomeric HNBR–MgO composite: Magnesium oxide as a novel swelling and reinforcement filler

Abstract In this paper, we introduce a novel reactive rubber composite made by compounding magnesium oxide (MgO) powder with hydrogenated nitrile butadiene rubber (HNBR). This HNBR–MgO composite system initially looks and behaves like rubber, but exposure to water causes it to swell and stiffen. Compared with conventional swellable materials, which lose stiffness significantly upon swelling, the sealing capacity of these novel reactive composites improves significantly with their improved stiffness. Three mixing ratios of HNBR and MgO were examined in this study, and their properties upon reaching equilibrium in water of 82 °C were reported. The elastic modulus value tripled, reaching 80 MPa, while doubling in volume for the rubber filled with 40% by volume of MgO. After drying, modulus of this particular composite increased even further to almost 200 MPa while the volume expansion was largely retained (shrinkage of approximately 10%). In this paper, we will show that the increase in elastic modulus and volume increase are related to the reaction of MgO with water to form magnesium hydroxide, absorbing water molecules into the composite and chemically reacting with it in the process.

Toughening of PA6 nanocomposites by reactive acrylonitrile–butadiene–styrene core–shell rubber particles

The effect of addition of organoclay and the reactive ABS‐g‐MA core‐shell particles on the mechanical properties and morphology of blends of polyamide (PA6) were reported. The reactive rubber particles with core‐shell structure were selected as modifier instead of conventional reactive bulk rubber. The microstructure of the ternary nanocomposites was characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Impact strength and stress–strain behavior of blends were measured as a function of organoclay content and core/shell ratio of ABS‐g‐MA. The organoclay plates affected the interfacial adhesion between polyamide and the core‐shell particles because of a shielding effect of organclay on the interacting of amine end groups of PA6 with the MA groups of ABS‐g‐MA. The poor dispersion behavior of ternary nanocomposites was observed when the core/shell ratio is 80/20, and with an increase of organoclay content, the core/shell dispersed phase size increased. Blends based on the maleated elastomer with the core/shell ratio 60/40 gave a more beneficial balance of toughness versus stiffness. POLYM. COMPOS., 35:864–871, 2014. © 2013 Society of Plastics Engineers