Unsaturation styrene-butadiene copolymers

We have considerable latitude when it comes to choosing the chemical composition of rubber toughened polystyrene. Suitable unsaturated rubbers include styrene-butadiene copolymers, cis 1,4 polybutadiene, and ethylene-propylene-diene copolymers. Acrylonitrile-butadiene-styrene is a more complex type of block copolymer. It is made by swelling polybutadiene with styrene and acrylonitrile, then initiating copolymerization. This typically takes place in an emulsion polymerization process. 

Solomon (3, h, 5.) reported that various clays inhibited or retarded free radical reactions such as thermal and peroxide-initiated polymerization of methyl methacrylate and styrene, peroxide-initiated styrene-unsaturated polyester copolymerization, as well as sulfur vulcanization of styrene-butadiene copolymer rubber. The proposed mechanism for inhibition involved deactivation of free radicals by a one-electron transfer to octahedral aluminum sites on the clay, resulting in a conversion of the free radical, i.e. catalyst radical or chain radical, to a cation which is inactive in these radical initiated and/or propagated reactions. 

PS PSF PSU PTFE PU PUR PVA PVAL PVB PVC PVCA PVDA PVDC PVDF PVF PVOH SAN SB SBC SBR SMA SMC TA TDI TEFE TPA UF ULDPE UP UR VLDPE ZNC Polystyrene Polysulfone (also PSU) Polysulfone (also PSF) Polytetrafluoroethylene Polyurethane Polyurethane Poly(vinyl acetate) Poly(vinyl alcohol) poly(vinyl butyrate) Poly(vinyl chloride) Poly(vinyl chloride-acetate) Poly(vinylidene acetate) Poly(vinylidene chloride) Poly(vinylidene fluoride) Poly(vinyl fluoride) Poly(vinyl alcohol) Styrene-acrylonitrile copolymer Styrene-butadiene copolymer Styrene block copolymer Styrene butadiene rubber Styrene-maleic anhydride (also SMC) Styrene-maleic anhydride (also SMA) Terephthalic acid (also TPA) Toluene diisocyanate Ethylene-tetrafluoroethylene copolymer Terephthalic acid (also TA) Urea formaldehyde Ultralow-density polyethylene Unsaturated polyester resin Urethane Very low-density polyethylene Ziegler-Natta catalyst... 

Unsaturated elastomers can be readily metallated with activated organolithium compounds in the presence of chelating diamines or alkoxides of potassium or sodium. For example, polyisoprene, polybutadiene, styrene-butadiene copolymers, and styrene-isoprene copolymers can be metallated with n-butyllithium TMEDA complexes (1/1 or 1/2 ratio) to form allylic or benzylic anions. The resulting allylic anion can be employed as an initiator site to grow certain branched or comb polymer species. These polymers can include polystyrene, which would form hard domains, or polybutadiene, which forms soft domains. 

Determination of Unsaturation in Ethylene-Propylene-Diene Terpoiymers and Styrene-Butadiene Copolymers... 

In this chapter the homopolymer, polystyrene, is considered together with styrene-acrylonitrile copolymers, acrylonitrile-butadiene-styrene copolymers and styrene-a-methylstyrene copolymers. The important styrene-butadiene copolymers are described with other diene polymers in Chapter 18. The use of styrene in the cross-linking of unsaturated polyesters is described in Chapter 10. 

Polyester (unsaturated) copolymers Styrene-butadiene rubber Ethylene-vinyl acetate Styrene-butadiene copolymers... 

Other workers who have investigated the applications of NMR spectroscopy to the analysis of unsaturation in polybutadiene and styrene-butadiene copolymers inclnde Carlson and Altenau [26], Carlson and co-workers [27], Binder [28, 29], Braun and Canji [30, 31], Hast and Deur Siftar [32], Silas and co-workers [33], Cornell and Koenig [15], Neto and Di Lauro [34], Binder [28], Clark and Chen [35] and Harwood and Ritchey [36]. 

Furthermore, the norbornene derivatives could be polymerized in the presence of unsaturated polymers like polybutadiene or styrene-butadiene copolymer(SBR) to give block or graft copolymers. The formation of the block(graft) copolymer was substantiated by the electronmicroscopy, which revealed a two-phase structure of the products in the solid state. The block copolymerization with a unsaturated rubbery polymer was successfully utilized to improve the impact resistance of the homopolymers of norbornenenitriles. 

Crompton and Reid [113] have described procedures for the separation of high impact polystyrene, i.e., styrene-butadiene copolymer, into the free rubber plus rubber grafted polystyrene plus copolymerised rubber and a gel fraction and for estimating total unsaturation in the two separated fractions. To separate a sample into gel and soluble fractions it was first dissolved in toluene. Only gel remains undissolved. Methanol is then added, which precipitates the polystyrene - rubber graft, ungrafted rubber and polystyrene. Any styrene monomer, soap or lubricant remain in the liquid phase, which is separated from the solids and rejected. 

Panyszach and Kovar [125] have shown that results accurate to within 2.5% can be obtained in determinations by FTIR of the butadiene content of styrene - butadiene copolymers. Infrared methods are reported to have serious disadvantages when applied to the determination of unsaturation in vulcanisates [126-130]. 

This technique has been used extensively for the determination of functional groups, in polymers and copolymers (Chapter 3) and in comonomer analysis (Chapter 4). Both these aspects are concerned with the determination of polymer structure. For example the distinction between free and combined vinyl acetate in vinyl chloride - vinyl acetate copolymers (Section 3.4.4) or the elucidation of the structure of methylmethacrylate (MMA) - glycidyl methacrylate copolymers (Section 3.6.1) or the elucidation of the various types of unsaturation occurring in styrene - butadiene copolymers (Sections 3.9.3, 3.9.4). Typical infrared (IR) spectra of copolymers are shown in Figures 6.1 to 6.4. 

The products have superior mechanical properties compared with the random copolymers or blends of homopolymers of the same overall composition. The literature reports block copolymers of polybutadiene with cyclopentene [69a], cyclooctadiene [69b], cyclodo-decene [69c] and substituted norbornenes [69d], of polyisoprene, polychloroprene, polypentenamer, and butyl rubber with norbornene derivatives [69c] and styrene-butadiene copolymers with cyclopentene [69a] and norbornene derivatives [69c]. Graft copolymers of type (103) will arise when unsaturation occurs in branched arms of the polymer to be grafted (e.g., 1,2-polybutadiene with cycloolefins) ... 

The most widely used elastomers are natural rubber [17], synthetic polyisoprene and butadiene rubbers, styrene-butadiene copolymers, ethylene-propylene rubber (specifically EPDM), butyl and halobutyl elastomers, polyurethanes, polysiloxanes, polychloroprenes, nitrile rubber, polyacrylic rubbers, fluorocarbon elastomers, and thermoplastic elastomers [18-20]. The examples which have unsaturation present in the repeat units (such as, the diene elastomers) have the advantage of easy cross-linkability, but the disadvantage of increased vulnerability to attack by reactants, such as oxygen and ozone. 

Organic peroxides are used in the polymer industry as thermal sources of free radicals. They are used primarily to initiate the polymerisation and copolymerisation of vinyl and diene monomers, eg, ethylene, vinyl chloride, styrene, acryUc acid and esters, methacrylic acid and esters, vinyl acetate, acrylonitrile, and butadiene (see Initiators). They ate also used to cute or cross-link resins, eg, unsaturated polyester—styrene blends, thermoplastics such as polyethylene, elastomers such as ethylene—propylene copolymers and terpolymers and ethylene—vinyl acetate copolymer, and mbbets such as siUcone mbbet and styrene-butadiene mbbet. 

Styrene [100-42-5] (phenylethene, viaylben2ene, phenylethylene, styrol, cinnamene), CgH5CH=CH2, is the simplest and by far the most important member of a series of aromatic monomers. Also known commercially as styrene monomer (SM), styrene is produced in large quantities for polymerization. It is a versatile monomer extensively used for the manufacture of plastics, including crystalline polystyrene, mbber-modifted impact polystyrene, expandable polystyrene, acrylonitrile—butadiene—styrene copolymer (ABS), styrene—acrylonitrile resins (SAN), styrene—butadiene latex, styrene—butadiene mbber (qv) (SBR), and unsaturated polyester resins (see Acrylonithile polya rs Styrene plastics). 

Styrene-1,3-butadiene copolymers with higher styrene contents (50-70%) are used in latex paints. Styrene and 1,3-butadiene terpolymerized with small amounts of an unsaturated carboxylic acid are used to produce latexes that can be crosslinked through the carboxyl groups. These carboxylated SBR products are used as backing material for carpets. Styrene copolymerized with divinyl benzene yields crosslinked products, which find use in size-exclusion chromatography and as ion-exchange resins (Sec. 9-6). 

Use of these polar randomizers also increases the vinyl unsaturation in the copolymer. Butadiene-styrene random copolymers can also be prepared by a very slow and continuous addition of monomers22. or by an incremental addition of butadiene to a styrene-rich monomer mixture during polymerization. These two... 

Scavenger compounds that have been patented include unsaturated fatty acids [19], sulfonyl hydrazides [20], cyclopentadienes [21], styrene-butadiene block copolymers [22], peroxides [23], and terpenes [24],... 

Styrene is produced by the alkylation of benzene with ethylene followed by catalytic dehydrogenation. It is used in the manufacture of general-purpose and high-impact polystyrene plastics ( 50%), expanded polystyrene ( 7%), copolymer resins with acrylonitrile and butadiene ( 7%) or acrylonitrile only ( 1%), styrene-butadiene latex ( 6%) and synthetic rubber ( 5%), unsaturated polyester resins ( 6%), and as a chemical intermediate. 

After the paper making process is complete, latexes that are useful as binders for the application of clays or CaCC>3 to paper for printing paper may be prepared using the dimer of AMS. In a typical formulation, styrene, butadiene, Me methacrylate, and acrylonitrile were emulsion polymerized in the presence of AMS dimer to obtain a copolymer latex.473 Surprisingly, the AMS dimer was used in combination with tert-dodecylmercaptan, so there may have been some residual odor. Unsaturated carboxylic acids, such as acrylic acid, or sulfonic acids, such as 2-ethylsulfonyl acrylate, or unsaturated amides, such as acrylamide, are also useful, providing the polarity necessary in these applications.474... 

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