China
Africa
Explore chapters and articles related to this topic
Block Copolymer-Based Hot-Melt Pressure-Sensitive Adhesives
Published in István Benedek, Mikhail M. Feldstein, Technology of Pressure-Sensitive Adhesives and Products, 2008
Other modifications to SBC polymers include functionalizing SIS with hydroxyl groups [6] and using acrylic oligomers to modify anionically polymerized SBCs. The acrylic oligomers contain at least one functional group such as ester, carboxylic acid, anhydride, or epoxy [7]. The introduction of these functional groups considerably enhances adhesion to polar substrates and broadens the compatibility of SBCs with other polymers and tackifiers. Kraton Polymer LLC has also developed functionalized block copolymers, but for a different purpose [8]. They first prepare isoprene and butadiene diblock copolymers through a sequential process and then selectively hydrogenate almost all double bonds in the butadiene blocks and some of the double bonds in the isoprene blocks. The remaining unsaturated double bonds are epoxidized. Further cross-linking through the epoxy functionality provides the needed adhesive strength, typically through UV-initiated cationic cure [9,10] (see also Chapters 1 and 8). An example of epoxidized block copolymer from Kraton is EKP-207.
Thermoplastic Elastomers
Published in Anil K. Bhowmick, Current Topics in ELASTOMERS RESEARCH, 2008
Francis R. Costa, Naba K. Dutta, Namita Roy Choudhury, Anil K. Bhowmick
TPEs appeared in the market as commercial products in the late 1950s with the introduction of thermoplastic polyurethane (TPU, B.F. Goodrich Co.). This was preceded by activity in 1930s and 1940s that led to the introduction of TPU in Germany and polyvinyl chloride (PVC) in the United States. By the 1960s, TPEs were in their infancy. During this period enormous research efforts were devoted to the development of novel block copolymer TPE and a variety of blends of thermoplastic polyolefins (TPO) with elastomers. In 1965, the company Shell developed and introduced commercial styrene diene block copolymer, Kraton. The 1970s saw the emergence of commercial copolyester, Hytrel from DuPont and blends of polypropylene (PP) and ethylene–propylene–diene monomer (EPDM) rubber from Uniroyal. During this period, it was realized that TPE would have a bright and promising future in both the rubber and the plastic industries. Thus extensive research efforts were devoted toward their development and commercialization. As a consequence, the 1980s witnessed the growth of TPE to maturity. Table 5.2 illustrates the milestones for the commercialization of TPEs.
The Role of Interfaces and Phase Morphology on Mechanical Properties of Multiphase: Copolymer Systems
Published in Charef Harrats, Sabu Thomas, Gabriel Groeninckx, Micro- and Nanostructured Multiphase Polymer Blend Systems, 2005
Roland Weidisch, Manfred Stamm
Figure 5.13 shows a comparison between two multigraft copolymers and two commercial TPEs, a Shell Kraton® and a BASF Styroflex®. Kraton, one of the leading commercial TPE on the market, is a typical SBS triblock copolymer with a hexagonal morphology. Styroflex is a S-SB-S triblock copolymer with a SB random copolymer as the middle block provided by the BASF Company. Styroflex shows a higher yield stress and tensile strength than Kraton but a lower strain at break. Obviously, the tetrafunctional multigraft copolymers show much higher strains at break than observed for the commercial TPEs. For a multigraft copolymer with 22% PS and 10 branch points, the strain at break is almost twice that observed for Kraton with 20% PS. The combination of a huge strain at break and an acceptable tensile strength of about 21 MPa indicate an exceptional property profile for tetrafunctional multigraft copolymers.
Viscoelastic behavior of pressure-sensitive adhesive based on block copolymer and kraft lignin
Published in The Journal of Adhesion, 2023
Rogerio R. de Sousa Júnior, Guilherme E.S. Garcia, Demetrio J. dos Santos, Danilo J. Carastan
The base polymer used to prepare the PSA in this work was polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS – Kraton G1652), a triblock copolymer with 30 wt% PS blocks. It was provided by Kraton (Paulinia/Brazil). White mineral oil (MO) from Dinâmica (Diadema/Brazil), a mixture of liquid hydrocarbons derived from petroleum, was chosen due to its selective interaction with the flexible ethylene-butylene (EB) block of SEBS,[30,31] enabling the adjustment of the viscoelastic behavior of the polymer. The tackifier selected for this work was Sukorez SU-120, a hydrogenated hydrocarbon resin (HCR) supplied by Kolon Chemical (South Korea). This thermoplastic, obtained from the polymerization and hydrogenation of dicyclopentadiene (DCPD), was also chosen for its ability to improve the viscoelastic properties of the PSA by interacting with the SEBS midblock. Table 1 presents the main characteristics of the materials used.
Numerical modeling of a human tissue surrogate SEBS gel under high velocity impacts: investigation of the effect of the strain rate in an elasto-hydrodynamic law
Published in Mechanics of Advanced Materials and Structures, 2022
Jianbo Shen, Lorenzo Taddei, Sebastien Roth
The soft tissue substitute material applied in this study is the same synthetic polymer SEBS gel (styrene-ethylene-butylene-styrene) used by Bracq et al. [26]. It is a triblock copolymer produced by Kraton Polymers LLC (G1652). The 30 wt% SEBS gel is obtained by mixing SEBS powder and mineral oil with the styrene/elastomer ratio of 30/70%. The mineral oil is supplied by ESSO S.A.L (PRIMOL 352). The manufacturing process of this gel does not need complicated equipment and is comparatively straightforward. An oven is used to place a metallic drum where the mineral oil is preheated at 100° C for 2 h. The SEBS powder is added in gradually and mixed continuously at the same time. Then increase the temperature to 150° C and keep the mixtures soaked for 4 h with intermittent mixing. After the mixture liquid is fully melted and there exists no bubble, the liquid is cast into an appropriate mold with a dedicated geometry. The liquid is cooled to room temperature slowly before the removal from the mold in order to reduce the sink deformation. The material density of this SEBS gel is about 880 kg/m3.
Reduction of thrombotic and inflammatory complications of polystyrene-block-polyisoprene-block-polystyrene (SIS) with one-step electrospinning
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Haozheng Wang, Zhifang Ma, Jingchuan Liu, Qiang Shi, Jinghua Yin
The triblock copolymer polystyrene-polyisoprene-polystyrene (SIS, Kraton D1107) was purchased from Sigma-Aldrich. Pluronic F127 was purchased from Sigma-Aldrich. Acylated Pluronic F127 (F127-DA) was synthesized in a reaction by covalent binding with acryloyl chloride and Pluronic F127 [22]. The pure and synthesized polymers were characterized by 1H-NMR spectrometer and FT-IR measurements (Figure S1). Benzophenone (BP) was provided by Peking Ruichen Chemical (China). Pentaerythritoltetrakis (3-mercaptopropionate) (PETM) was obtained from Sigma-Aldrich. 2-O-d-Glucopyranosyl-l-ascorbic Acid (AA-2G) was purchased by Tokyo Chemical Industry. Chloroform, trimethylamine, acrylamide, acetone and xylene were reagent grade products. Other reagents were AR grade and used without further purification.