Block styrenic

Asaparene Linear block styrene copolymer with butadiene Asahi... 

Flexprene Linear block styrene Teknor Apex... 

Linear block styrene copolymers with ethylene-propylene PS PP SAN... 

Stearon Linear block styrene-butadiene copolymers Firestone... 

The last property is related to the processing of the rubber in the tire making equipment. By using organo-lithium compound in this case, it was possible to maintain a vinyl content not greater than 18, but to produce a polybutadiene styrene copolymer that has random block styrene and without the use of polar modifiers, which normally will increase the 1,2 content. This copolymer, when compounded in the tread recipe, as shown in the Table XVI, gave properties that are actually equivalent to that of emulsion SBR and in some cases even better. This is particularly true in the properties of the Young modulus index, which showed between -38 to -54 C the Stanley London Skid Resistant, in which the control is 100, shows that 110-115 was obtained. 

The copolymerization of butadiene-styrene with this initiator was carried out heterogeneously in hexane. The data in Table VI show that the styrene content is highly dependent on the percent of conversion. It appears that a block styrene would be obtained if 100% conversion were reached. A detailed discussion regarding this subject will be mentioned later. 

At this stage, we do not know whether the styrene incorporated in polymer chain is a block styrene or not. However, it is speculated that the block styrene will be resulted based on the lithium morpholinide system. More work along this line is in need in order to qualify this statement. 

Diblock copolymers, especially those containing a block chemically identical to one of the blend components, are more effective than triblocks or graft copolymers. Thermodynamic calculations indicate that efficient compat-ibilisation can be achieved with multiblock copolymers [47], potentially for heterogeneous mixed blends. Miscibility of particular segments of the copolymer in one of the phases of the bend is required. Compatibilisers for blends consisting of mixtures of polyolefins are of major interest for recyclates. Random poly(ethylene-co-propylene) is an effective compatibiliser for LDPE-PP, HDPE-PP or LLDPE-PP blends. The impact performance of PE-PP was improved by the addition of very low density PE or elastomeric poly(styrene-block-(ethylene-co-butylene-l)-block styrene) triblock copolymers (SEBS) [52]. 

Tureau MS, Epps TH (2009) Nanoscale networks in poly[isoprene-block-styrene-block-(methyl methacrylate)] triblock copolymers. Macromol Rapid Commun 30 1751-1755... 

SB), multi-block styrene-butadiene correlation distance... 

Hauser et al. [1993] claim that articles for medical and other uses made from a polymer alloy of a clear styrenic acrylate, a ductile styrene-diene polymer, and a rubbery block styrene-diene copolymer may be sterihzed by gamma irradiation, without significant increase in its yellowness index or significant deterioration of the alloy s mechanical properties (Table 11.9). There are many applications, e.g., urine sample botdes, items in space probes, and cosmetic containers, that are made from transparent plastics and need to be radiation-sterihzed. However, many clear plastics do develop color on irradiation, and their mechanical properties tend to deteriorate, particularly on irradiation in air. Hauser et al. 

In general, random SBR with a low amount of block styrene and low amounts of 1,2-butadiene enchainment (<20%) can be prepared in the presence of small amounts of added potassium or sodium metal alkoxides [214, 215]. For example, at 50 °C in the presence of as little as 0.067 equivalents of potassium f-butoxide in cyclohexane, the amount of bound styrene was relatively independent of conversion, in contrast to the heterogeneity observed in the absence of randomizer, that is, tapered block copolymer formation [214]. The polybutadiene microstructure obtained under these conditions corresponds to about 15%... 

KRATON polymers are high-performance elastomers used to improve the properties of a wide range of end products. KRATON G polymers are triblock copolymers, with a random ethylene/propylene copolymer forming the saturated midblock and styrene forming the two other blocks (styrene-ethylene/propylene-styrene, SEPS). 

A-ethylene-butylene center block . - Styrene end block... 

Shell Kraton Di-block and tri-block styrene-butadiene... 

Lawson and co-workers have described the preparation and use of hydrocarbon-soluble lithium amides such as the N-lithio salts of l,3,3-trimethyl-6-azabicyclo[3.2.1]octane (21) and hexamethyleneimine (22). The initiator 21 was soluble when prepared by metalation of the bicyclic amine with n-butyllithium in hexanes. Initiator 21 in the presence of 0.27 equivalents ofTMEDA was used to polymerize an 80/20 (wt/wt) blend of butadiene and styrene at 50 °C in hexanes.After conventional termination and work-up, the resulting polymer exhibited a good correspondence between calculated (Aln= 100 X lO gmoP ) and observed (Aln = 99.7 x 10 gmol ) molecular weights, a relatively broad molecular weight distribution (Al /Aln = 1 82), and 52% 1,2-microstructure (Tg= -42 °C) with little (0.7%) block styrene. 

Quite surprisingly, it was reported that initiator 22 was soluble in a mixture of 80/15 (wt/wt) q clohexane/hexanes. Polymerization of an 80/20 (wt/wt) blend of butadiene and styrene at 50 ° C in hexanes using 22 as initiator was carried out in the presence of 0.30 equivalents of TMEDA relative to lithium. After conventional termination and work-up, the resulting polymer exhibited a molecular weight distribution M /M = 1.27) which was narrower than the distribution for the SBR prepared with initiator 21 the polymer exhibited 2% block styrene and 35% 1,2-microstructure (Tg=-50°C). Procedures have been described for solubilization of insoluble lithium amides by direct chain extension with butadiene or addition of 2 equivalents of a polar, solubilizing additive such as THF. ... 

Block copolymers - Copolymers with two or more repeating units ( A and B) are arranged in a block within the chain. They may be represented schematically as -A-A-A-A-A-B-B-B-B-B-B-B-A-A-A-A-B-B-B-. Poly(butadiene-block-styrene) is an example of a block copolymer. 

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