Styrene Isoprene Research Articles

Scandium-catalyzed stereoselective block and alternating copolymerization of diphenylphosphinostyrenes and isoprene

The coordination copolymerization of polar diphenylphosphinostyrenes and isoprene by (C5Me4SiMe3)Sc(CH2C6H4NMe2-o)2 afforded a new series of phosphine-functionalized alternating and block isoprene–styrene copolymers.

Decrease in viscosity of styrene‐isoprene‐styrene filling systems induced by micro elastic phase

AbstractThe melt viscosity of triblock copolymer styrene‐isoprene‐styrene (SIS) filling systems decreased in some sense by adding 0.1 wt% fillers. The types of fillers included both nano‐ and non‐nano fillers. It was insufficient to explain the phenomenon of viscosity reduction only from the view of nanoscale effects of particles. The results of SAXS and TEM enabled us to relate this behavior to the damage of PS microphase in SIS. The PS microphase acted as a strong entanglement point in the SIS system. When it was damaged, the entanglement among molecular chains weakened greatly, resulting in a decrease in viscosity. The dynamic viscoelasticity (complex viscosity, storage modulus, and loss modulus) of the filling systems was also studied.

Studies of the Sulfonated Hydrogenated Styrene-Isoprene-Styrene Block Copolymer and Its Surface Properties, Cytotoxicity, and Platelet-Contacting Characteristics.

Styrenic thermoplastic elastomers (TPEs) consist of styrenic blocks. They are connected with other soft segments by a covalent linkage and are widely used in human life. However, in biomedical applications, TPEs need to be chemically hydrogenated in advance to enhance their properties such as strong UV/ozone resistance and thermal-oxidative stability. In this study, films composed of sulfonated hydrogenated TPEs were evaluated. Hydrogenated tert-butyl styrene–styrene–isoprene block copolymers were synthesized and selectively sulfonated to different degrees by reaction with acetyl sulfate. By controlling the ratio of the hydrogenated tert-butyl styrene–styrene–isoprene block copolymer and acetyl sulfate, sulfonated films were optimized to demonstrate sufficient mechanical integrity in water as well as good biocompatibility. The thermal plastic sulfonated films were found to be free of cytotoxicity and platelet-compatible and could be potential candidates in biomedical film applications such as wound dressings.

Mechanical and Aging Properties of Polypropylene and Styrene-Isoprene-Styrene Composites at Low Temperature and Under Outdoor Conditions

Polypropylene (PP) and styrene-isoprene-styrene (SIS) blends with different mass fractions were prepared by twin-screw melt extrusion. PP/SIS was analyzed with differential scanning calorimetry, a universal material testing machine, capillary rheometry, X-ray diffractometry, and X-ray photoelectron spectrometry. The SIS content effect on the microstructure and properties was discussed, and the morphology and mechanical properties of outdoor-aged PP/SIS samples were studied. The SIS addition is shown to improve the PP toughness. Low-temperature tests and dynamic thermal analysis demonstrate that the low-temperature PP brittleness can be effectively enhanced by a good low-temperature SIS toughness. Indoor and outdoor aging tests revealed that the PP/SIS samples were greatly affected by the outdoor climate, but in comparison with pure PP samples, the properties of blend samples still have certain advantages offered by simple blending modification.

Synthesis of butadiene/isoprene-styrene di-block copolymer with high cis-1,4 unit content based on a neodymium phosphate ester.

A novel two-step synthesis strategy based on a liquid neodymium phosphate ester (Nd(P507)3) catalyst was used to synthesize diene-styrene di-block copolymers with high cis-1,4 unit content, such as butadiene–styrene (PB-b-PS), isoprene–styrene (PI-b-PS), and so on. The strategy not only makes full use of the high cis-1,4 stereo-selectivity of the rare earth catalyst to conjugated dienes, but also adjusts the electron cloud density of the catalytic active center by introducing triphenyl phosphine (PPh3). Thus, the catalytic activity of the neodymium-based catalyst center toward styrene has been largely improved, and a series of PB/PI-b-PSs with high cis-1,4 unit content (98.3 and 98.1% respectively), narrow molecular weight distribution and controllable block ratio were successfully synthesized. Herein, molecular weight (Mn), molecular weight distribution (Mw/Mn) and microstructure of the block polymers were characterized using SEC-MALLS, FT-IR, 1H NMR, 13C NMR and DSC. The DSC curve of a PB-b-PS with 98.3% cis-1,4 unit and 18.6% polystyrene content shows a Tg of −103.1 °C, which means it has relatively excellent mechanical properties at lower temperature. The results show that these PB/PI-b-PS materials have good application prospects in harsh low temperature environments.

Сравнительная оценка озоностойкости и атмосферостойкости резин при ускоренных и натурных условиях старения

The authors compared the results of determining the ozone resistance (OR) and weather resistance (WR) obtained in laboratory and natural conditions of tropical climate. The samples were manufactured with unsaturated rubbers (nitrile butadiene rubbers BNKS-18AN, BNKS-28AN, BNKS-40AN and SKN-26PVC-30, styrene butadiene rubber SKMS-30 ARKM, isoprene SKI-3 and butadiene SKD-ND). All the samples were not filled with antioxidants or antiozonants. The curing process at 160 °C and the total crosslink density (νt) were studied using a MonTech MDR 3000 Professional rotorless rheometer. The physical and mechanical properties of the vulcanizates were determined with the using of a Zwick\Roell Z010 tensile testing machine at a test speed of 500 mm / min. Hardness and tear resistance were also determined. The numerical estimate of νt was obtained from the data on the dynamic shear modulus. Density of chemical bonds νch was determined from the data of equilibrium swelling in toluene according to the Flory-Rener equation. Full-scale climatic tests in tropical climate in the south of the Republic of Vietnam were carried out for 9 months in accordance with GOST 9.066-76 with initial deformations of 10, 20, 30, 40 %. The sample stand was oriented south, at a 45 degree angle. Cracks formed on the rubber surface were recorded by photography. The time before the onset of fracture Tof and the time until the appearance of the first cracks Tfc were determined. It is shown that samples of rubbers with high OR in laboratory tests had the best WR. A correlation of νch with Tof and Tfc was revealed. The obtained results show the possibility of using the express method for assessing the OR of rubbers in the development of formulations for tropical climates.

Preparation of Magnetorheological Fluid Using Stabilizing Additives

In this study, we examined three kinds of stabilizing additives to prepare stable MRF with good fluidity. We selected three stabilizing additives; a styrene isoprene block copolymer, a hydrophobic fumed silica, and an organogelator (CMOL SB03; PMDA-2C8/oleyl). We measured the rheological properties both for the dissolutions of the stabilizing additives in the base oil and MRFs prepared with the additives by using a rheometer; MCR302 (Anton Paar Corp.). From the experimental results, the viscosity of styrene isoprene block copolymer dissolution increased with concentration showing non-Newtonian properties. We selected a suitable concentration as 5wt% to satisfied good fluidity without forming gel. Since the viscosities of 7wt% fumed silica and 1wt% CMOL SB 03 dissolutions in the base oil consequently showed similar viscosity of the 5wt% copolymer, MRFs using such conditions were prepared. From the results of the stability test, the addition of the copolymer was effective to satisfy the stability of the MRF. We also found that the addition of such stabilizing additives were effective to increase the magnetic property of MRFs.

Deep Regression Prediction of Rheological Properties of SIS-Modified Asphalt Binders.

The engineering properties of asphalt binders depend on the types and amounts of additives. However, measuring engineering properties is time-consuming, requires technical expertise, specialized equipment, and effort. This study develops a deep regression model for predicting the engineering property of asphalt binders based on analysis of atomic force microscopy (AFM) image analysis to test the feasibility of replacing traditional measuring estimate techniques. The base asphalt binder PG 64-22 and styrene–isoprene–styrene (SIS) modifier were blended with four different polymer additive contents (0%, 5%, 10%, and 15%) and then tested with a dynamic shear rheometer (DSR) to evaluate the rheological data, which indicate the rutting properties of the asphalt binders. Different deep regression models are trained for predicting engineering property using AFM images of SIS binders. The mean absolute percentage error is decisive for the selection of the best deep regression architecture. This study’s results indicate the deep regression architecture is found to be effective in predicting the G*/sin δ value after the training and validation process. The deep regression model can be an alternative way to measure the asphalt binder’s engineering property quickly. This study would encourage applying a deep regression model for predicting the engineering properties of the asphalt binder.

Laboratory Evaluation of Sustainable PMA Binder Containing Styrene-Isoprene-Styrene (SIS) and Thermoplastic Polyurethane

In this study, thermoplastic polyurethane (TPU) and styrene-isoprene-styrene (SIS) were utilized to enhance asphalt binder properties. Superpave asphalt binder tests and multiple stress creep recovery (MSCR) were conducted to evaluate the physical and rheological performance (viscosity, rutting, and cracking properties) of the asphalt binders before and after short-term aging and after the long-term aging process. The results showed that (i) TPU has a positive effect on workability, including the mixing and compaction processes, which was evident from the reduced binder viscosity; (ii) asphalt binders with TPU and SIS showed better rutting resistance compared to the SIS binders without TPU; (iii) the cracking resistance of asphalt binders was found to be improved significantly with the addition of TPU; and (iv) TPU has the potential to be considered as a sustainable polymer modifier for producing bearable asphalt binders by improving rutting and crack resistance without increasing the melting temperature of the asphalt binders.

Wall slip of styrene-isoprene-styrene (SIS) triblock copolymer induced by micro elastic phase

Wall slip of styrene-isoprene-styrene (SIS) triblock copolymer was investigated during the capillary extrusion flow. The origin of the unique flow behavior of SIS was explored. Wall slip velocity of the SIS at 150 °C was calculated by the Mooney method. The non-monotonic wall slip behavior exhibited by the SIS system in the weak wall slip region was due to the change of PS micro elastic phase. SAXS and DMA data confirmed that SIS had a viscous flow transition near 170 °C. The occurrence of this transition caused a significant change in the flow curve and wall slip state of the SIS.

Mesoporous silica filled smart super oleophilic fibers of triblock copolymer nanocomposites for oil absorption applications

Super oleophilic fibers of styrene-isoprene-styrene (SIS) block copolymer/mesoporous silica (MS) nanocomposites are fabricated by electrospinning, and their oil absorption efficiency is monitored by following two different approaches. The first way is by using the fibers as tubular packing materials for oil absorption, whereas the second approach uses the fibers as filtration membrane after deposition on the commercial polyethersulfone (PES) support. All composites are made by adding inorganic MS in different concentrations (2, 4, and 7 wt.%) to SIS block copolymer. The addition of MS increases the fiber diameters and leads to enlarged and bead-like appearances, especially at higher filler concentrations. The oil absorption efficiency is explored based on the oil absorption capacity of the samples as well as with the gravity-driven oil filtration experiments. The best oil absorption efficiency is achieved by the 4 wt.% SIS-MS composite (150% higher oil absorption capacity compared to the neat SIS), and it is used to spin on the PES mechanical support of different pore sizes (0.2 μ and 8 μ). Ultrafiltration tests conducted on those coated membranes observe improved oil rejection performance as the fibrous SIS-MS are layered on the commercial mechanical support.

Effect of Styrene-Diene Block Copolymers and Glass Bubbles on the Post-Consumer Recycled Polypropylene Properties

The recycled polypropylene (rPP) materials that meet technical requirements such as reducing the dimensions and improving the tensile, elongation, impact strength, thermal stability, as well as melt processing, are required for the manufacturing industry. In this paper, we studied the mechanical and thermal properties of post-consumer rPP by adding both synthesized thermoplastic elastomers, and glass bubbles (GB) by a melt allowing process. Styrene-butadiene (SBS) and styrene-isoprene (SIS) block-copolymers that had a styrene content of 30 wt% were synthesized by anionic sequential polymerization. The obtained post-consumer rPP composites were characterized by optical microscopy, scanning electron microscopy (SEM), mechanical analyses (tensile, density, hardness, VICAT softening temperature (VST), heat deflection temperature (HDT), dynamic mechanical analysis (DMA), IZOD strength) and thermal analyses (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). Weight reduction and improvement of the tensile, elongation, impact strength, thermal stability, as well as melt processing of post-consumer recycled polypropylene (rPP) properties compounded with thermoplastic elastomers and glass bubbles, sustain the use of these formulations for engineering applications.

Rheological and Morphological Characterization of Styrene‐Isoprene‐Styrene (SIS) Modified Asphalt Binder

The demand of strong polymer modified asphalt (PMA) binder is growing due to the increase of traffic and necessity to reduce the early deterioration of pavement due to cracking. In this study, physical and rheological properties of asphalt binder modified with a potential new polymer named styrene‐isoprene‐styrene (SIS) were investigated through the rotational viscometer (RV), the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). In order to have a depth understanding on the SIS binder at micro level, micro‐morphological observations were conducted using optical microscopy, atomic force microscopy (AFM), environmental scanning electron microscopy (ESEM), and ellipsometry. The result of this study showed that (1) the addition of SIS modifiers increased the viscosity and had a positive effect on rutting resistance of the binder; (2) the addition of 5%, 10%, 15%, and 20% SIS content increased the rutting resistance by 600%, 3000%, 5600%, and 6400%, respectively; (3) the higher the SIS content, the better the cracking resistance of the binder and it is observed to have improved the stiffness by 26% and 51% with the addition of 5% and 10% content of SIS, respectively; (4) AFM images showed the significant correlation between the stiffness and microstructural properties of the binder; (5) the dominance of new oval phase over network structure was evident in ESEM images and observed to have significant correlation to the high stiffness of the binder; and (6) with the percentage increase of SIS modifier, the binder is found to have higher absorption at UV wavelength.

Laboratory Evaluation of SBS Modified Asphalt Binder Containing GTR, SIS, and PE

Performance properties of polymer modified asphalt (PMA) binders with Styrene‐isoprene‐styrene (SIS), petroleum resin (PE), and ground tire rubber (GTR) were evaluated at high, intermediate, and low temperatures. Styrene‐butadiene‐styrene (SBS) PMA binder of PG 76‐22 was used as a base binder. The PG76 SBS PMA binders were blended with SIS, PE, and three different GTR contents (0, 5, and 10%). The binders were artificially short‐term and long‐term aged using rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were conducted on the binders through rotational viscometer (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR). Multiple stress creep recovery (MSCR) test was also performed to evaluate the rutting property. The results of this study indicated that (1) the addition of PE can decrease the binder viscosity, (2) although the incorporation of GTR and SIS significantly improve the rutting resistance of the binders, the effect of PE is found to be insignificant, (3) PE is observed to have positive effect on the cracking properties of control PG76 SBS PMA binder blended with SIS and GTR, and (4) incorporation of PE might be an useful option to improve the workability of high performance PMA binder in lieu with maintaining good rutting and cracking resistance.

Hydrogenation of Indene–Coumarone Resin on Palladium Catalysts for Use in Polymer Adhesives

Hydrogenation of indene–coumarone resin on commercial palladium catalysts, including crusted catalysts, was studied. The process parameters were optimized to reach the maximal hydrogenation of aromatic fragments with minimal thermal degradation of the macromolecules. The optimum conditions are as follows: temperature 230°C, pressure 3 MPa, resin concentration in the solvent 10–25 wt %. Comparative analysis of the activity of the tested catalysts shows that palladium on activated carbon exhibits the highest activity. The use of indene–coumarone resin as an adhesive component of polymer hot-melt and pressure-sensitive adhesives was considered. The rheology of the initial resins and adhesives based on them, the phase state of the formulations, and their adhesiveness were compared. The advantage of using the hydrogenated resin for preparing polymer adhesives based on styrene–isoprene–styrene triblock copolymer was demonstrated.

Adhesion performance and recovery of acrylic pressure-sensitive adhesives thermally crosslinked with styrene–isoprene–styrene elastomer blends for flexible display applications

Fixing layers in flexible displays requires acrylic pressure-sensitive adhesives (PSAs) that can withstand deformation and folding stress. In this study, the effects of a styrene–isoprene–styrene (SIS) elastomer on the adhesion performance and recovery of an acrylic PSA were investigated. In simple blends, the peel strength and probe tack of a PSA sheet decreased slightly as the SIS content increased owing to the elastomer’s soft nature. In contrast, the lap shear stress increased slightly owing to entanglement of the SIS polymer chains. In stress relaxation tests, the effect of SIS on PSA recovery was limited by weak bonding. Therefore, the use of thermal crosslinking to improve bonding within PSA/SIS blends was examined. Although increased crosslinking decreased the peel strength and probe tack, the adhesion properties were maintained and the lap shear stress and strain increased. Further, PSA recovery improved in stress relaxation tests, but a specific strain could not be endured above 1 phr crosslinking agent. Thus, crosslinking with an elastomer plays an active role in the adhesion performance and recovery of acrylic PSAs. However, as the PSA sheet becomes opaque in the presence of SIS, the display applications of this system are limited and further improvements are necessary.

Evaluation of High‐Performance Asphalt Binders Modified with SBS, SIS, and GTR

In this study, performance properties of polymer‐modified asphalt (PMA) binders are evaluated depending on ground tire rubber (GTR) and styrene‐isoprene‐styrene (SIS). Styrene‐butadiene‐styrene‐ (SBS‐) modified asphalt binder of PG 76‐22 is used as a base binder to manufacture the rubberized PMA binder. The rubberized PMA binders are blended using SIS modifier. The binders were artificially short‐term and long‐term aged using rolling thin‐film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were conducted on the binders through rotational viscometer (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR). Furthermore, multiple stress creep recovery (MSCR) test and atomic force microscopy (AFM) microstructural analysis were performed. The results of this study indicated that (1) the viscosity properties seem to be highly dependent on GTR and SIS contents, (2) the addition of SIS is observed to have a significant effect on improving the rutting performances of rubberized PMA binders, (3) the cracking properties are considered to be improved significantly through SIS modification, and (4) in general, the rubberized PMA binders with SIS showed the best performance for rutting and cracking among all the binders used in this study.

Swelling behaviours of styrene–isoprene–styrene triblock copolymers in supercritical methane

ABSTRACTStyrene–isoprene–styrene triblock copolymers (SIS) are representative thermoplastic elastomers possessing both elastomeric and thermoplastic feature. SIS have been used in self-healing cement for natural gas wells, but the mechanism behind the application was not unravelled. We hypothesise such self-repairing function should be associated with the swelling of SIS in natural gas whose main component is methane. It was found that all the four SIS copolymers show similar swelling trend irrespective of their structure difference, and the swelling ratio increases as decreasing the polystyrene block content in SIS. These preliminary pioneering findings show the swelling behaviour of the rubbers displayed quite differently before and after supercritical point, and it is helpful for the further research about the swelling behaviour of rubber in natural gas wells.

Adhesive Compositions Based on Styrene–Isoprene–Styrene Three-Block Copolymer with Different Modifiers

The adhesive properties of styrene–isoprene–styrene (SIS) three-block copolymer of different brands modified with isoprene oligomer and Regalite R9100 depending on the adhesive composition and the adhesion-contact-formation temperature were studied. It was shown that oligoisoprene acts as a diluent, while Regalite R9100 modifies the system as a whole by decreasing the glass-transition temperature of the microphase of polystyrene blocks and contributes to the increase in the adhesive ability of the composition.

The research for SIS compound modified asphalt

To improve the properties of styrene-isoprene-styrene (SIS) modified asphalt and decline the SIS content in asphalt further, SIS compound modified asphalt has been prepared by the addition of SIS, polyphosphoric acid (PPA) and sulfur. The physical and rheological properties of modified asphalts were studied and the structural characteristics were analyzed by adopting morphology observation, infrared spectroscopy and thermal analysis. The research showed the suitable addition of PPA improved the high- and low-temperature properties of asphalt and declined the SIS content without negative effect. The use of sulfur can improve the storage stability of modified asphalt greatly and increase the susceptibility to ageing. The morphology and infrared analysis indicate the effects of PPA, sulfur and ageing on the structural characteristics of asphalt. The calculation for the characteristic peaks of enthalpy curves in thermal analysis was used to investigate the influence of PPA and sulfur on the distribution of molecule weight and constitutes of SIS modified (SM) asphalt before and after ageing efficiently.