Isobutene—butene copolymer

The Polybutenes, random isobutene-butene copolymers predominantly composed of isobutene units, manufactured directly from the butanes-butenes C4 refinery stream, with low molar masses (MM) ranging from light to highly viscous liquids. 

With trimers, he observed that 75-83 percent of the trimer depolyalky-lated. He rationalized further that dimers could behave similarly this is a moot point, because yields of alkylate from butene monomers and dimers are identical when the alkylate formed during chain termination is considered. It was observed (Phillips Petroleum Comp>any, 1946) that Isobutene-butene copolymer yielded alkylate identical to that from the monomers. 

The products produced may be oligomers or high polymers [20,21]. Better known are isobutene copolymers with butenes [22], styrene [23], or cyclopenta-dienes [24]. 

Table IV. Yields of Isobutene and 1-Butene from Irradiation of Ethylene-a-Olefin Copolymers at 150°C...

The most important monomers for the production of polyolefins, in terms of industrial capacity, are ethylene, propylene and butene, followed by isobutene and 4-methyl-1-pentene. Higher a-olefins, such as 1-hexene, and cyclic monomers, such as norbornene, are used together with the monomers mentioned above, to produce copolymer materials. Another monomer with wide application in the polymer industry is styrene. The main sources presently used and conceivably usable for olefin monomer production are petroleum (see also Chapters 1 and 3), natural gas (largely methane plus some ethane, etc.), coal (a composite of polymerized and cross-linked hydrocarbons containing many impurities), biomass (organic wastes from plants or animals), and vegetable oils (see Chapter 3). 

The low-molecular-weight (Mn 500) butadiene-butene copolymers have 2 to 4.5 hydroxyl groups per chain. The 1,3-butadiene (Mt) reactivity is almost the same in copolymerization with butenes (M2) (rt = 0.08, 11.1 < r2 < 14.8). This copolymerization has been extended to the C4-petroleum fraction (essentially composed of 1-butene, 2-butene, isobutene, 1,3-butadiene)99). 

As it will be discussed In Sect. III.B.2.d), isobutene homopolymer and isoprene-iso-butene copolymer (butyl rubber) are prone to degrade under the attack of free radicals Therefore, these polymers cannot cross-link (unless h comonomer content is present) in the presence of free radicals and usually are not used in grafting reactions since a low degree of graft is observed (Tdrle 9, n 1,2). 

Similarly, 2-methylpropene (isobutene) is an important monomer. It only polymerizes by a cationic mechanism, and its copolymers with dienes are known as butyl rubber. Higher 1-alkenes (1-butene, 1-hexene, 1-octene) are important copolymerization components [4, 5] they produce tailored branching of some polyethylene types prepared by a coordination mechanism. Longer-chain alkenes (Cjq, C,2, Cj ) are also sometimes used as comonomers... 

Copolymers have also been prepared using mixtures of olefins with sulfur dioxide. Olefin pairs studied were butene with propylene [22-22b], butene with pentene [13], butene with isobutene [13b], butene with acrylonitrile [13,23], butene with vinyl acetate [24], butene with methacrylate esters [25], butene with acrylic esters [25], and butene with butadiene [24]. 

This technique has been applied to the gas chromatography of ethylene-butene copolymers [37]. Pyrolysis was carried out at 410 °C in an evacuated gas vial and the products swept into the gas chromatograph. Under these pyrolysis conditions, it is possible to analyse the pyrolysis gas components and obtain data within a range of about 10% relative. The peaks observed on the chromatogram were methane, ethylene, ethane, combined propylene and propane, isobutene, 1-butene, trans-l-hoXtm, cis-2-butene, 2-methyl-butene and -pentane. A typical pyrolysis chromatogram for polyethylene is shown in Figure 4.7. 

Using benzene solvent and a variety of initiators, Frank " described the preparation and properties of a-olefin-MA copolymers from propylene, 1-butene, isobutene, cis- and m 5-2-butene, 2-methyl-l-pentene, 2,4,4-trimethyl-1-pentene, 1-hexene, and 1-octene. In order to characterize the materials, the [r/]-Mvv relationship was elucidated for the polymers ... 

Poly(methyl methacrylate -block-t-butylaziridine) ABA type copolymer with MW 12000 butylaziridine (B) and MW 16000 Ambient to 600 CO, CH4, CO2, ethene, propene, isobutene, aziridine, methanol, methyl methacrylate, cc-methylstyrene, 2-phenyl-2-butene, 1 -t-butylamino-2-isopropenylamino-ethane, 2-r-butylaminoethyl-ethyl-isopropenylamine, 2-aminoethyl-2-r-butylaminoethyl-isopropenylamine, oligomers - principally butylaziridine based 287... 

At 26.7 mbar pressure 40% weight toss main product is 2,4-diphenyl thiophene at least 11 unidentified minor products CO2, H2O, butene, isobutene, dimethyl ketene, styrene, methacrylic acid, succinic-type 5-membered cyclic anhydrides Chlorotrifluoroethylene, styrene, HQ, chloropentafluoropropene, ethene, chloroethene, totuene, a-melhylstyiene, dimer and trimer structures with some unsaturation S1F4 (fiom reaction of HF with glass). Distribution of products varies with polymer composition CO, CO2, propene, isobutene, dimethyl ketene, acrolein, allyl alcohol, toluene, styrene, cl-methylstyrene, ethylbenzene, glycidol, glycidylmethacrylate product distribution depends on copolymer composition... 

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