Olefin copolymer, isobutylene

Until the mid-1950s the only polyolefins (polyalkenes) of commercial importance were polyethylene, polyisobutylene and isobutylene-isoprene copolymers (butyl rubber). Attempts to produce polymers from other olefins had, at best, resulted only in the preparation of low molecular weight material of no apparent commercial value. 

A second olefin copolymer with a more promising structure is that with isobutylene (2-methylpropene-l). Poly isobutylene itself is a chain-scissioning polymer which has been studied often. It is not much used as a positive resist despite its G(s) of 1.5 to 5 (21) because its Tg is so low, about -60°C. 

Polymers account for about 3—4% of the total butylene consumption and about 30% of nonfuels use. Homopolymerization of butylene isomers is relatively unimportant commercially. Only stereoregular poly(l-butene) [9003-29-6] and a small volume of polyisobutylene [25038-49-7] are produced in this manner. High molecular weight polyisobutylenes have found limited use because they cannot be vulcanized. To overcome this deficiency a butyl mbber copolymer of isobutylene with isoprene has been developed. Low molecular weight viscous Hquid polymers of isobutylene are not manufactured because of the high price of purified isobutylene. Copolymerization from relatively inexpensive refinery butane—butylene fractions containing all the butylene isomers yields a range of viscous polymers that satisfy most commercial needs (see Olefin polymers Elastomers, synthetic-butylrubber). 

Monomers for manufacture of butyl mbber are 2-methylpropene [115-11-7] (isobutylene) and 2-methyl-l.3-butadiene [78-79-5] (isoprene) (see Olefins). Polybutenes are copolymers of isobutylene and / -butenes from mixed-C olefin-containing streams. For the production of high mol wt butyl mbber, isobutylene must be of >99.5 wt % purity, and isoprene of >98 wt % purity is used. Water and oxygenated organic compounds iaterfere with the cationic polymerization mechanism, and are minimized by feed purification systems. 

However, a method to improve the flow properties of such fuel oils of animal or vegetable origin, has been developed (26). This consists in adding a EVA copolymer or a comb polymer based on methyl acrylate and a-olefins. In addition, terpolymers of ethylene, vinyl acetate and isobutylene have been found to be useful as cold flow improvers (29). 

In contrast to the polymers and copolymers of butadiene, the oligomers of aromatic olefins, like styrene, are not compatible with PVC. Oligomers of alkylated polystyrenes are a little better, especially in combination with other liquid plasticizers. Copolymers of styrene and isobutylene are not suitable for use with PVC. 

The first free radical initiated copolymerization was described by Brubakerl) in a patent. A variety of peroxides and hydroperoxides, as well as, 02, were used as initiators. Olefins that were copolymerized with CO included ethylene, propylene, butadiene, CH2=CHX (X—Cl, OAc, CN) and tetrafluoroethylene. A similar procedure was also used to form terpolymers which incorporated CO, C2H4 and a second olefin such as propylene, isobutylene, butadiene, vinyl acetate, tetrafluoroethylene and diethyl maleate. In a subsequent paper, Brubaker 2), Coffman and Hoehn described in detail their procedure for the free radical initiated copolymerization of CO and C2H4. Di(tert-butyl)peroxide was the typical initiator. Combined gas pressures of up to 103 MPa (= 15,000 psi) and reaction temperatures of 120—165 °C were employed. Copolymers of molecular weight up to 8000 were obtained. The percentage of CO present in the C2H4—CO copolymer was dependent on several factors which included reaction temperature, pressure and composition of reaction mixture. Close to 50 mol % incorporation of CO in the copolymer may be achieved by using a monomer mixture that is >70 mol% CO. Other related procedures for the free radical... 

Terpolymers made from two different olefins and CO are known. They were first described in Brubaker s initial patent and involved the free radical initiated terpolymerization of CO and C2H with another olefin such as propylene, isobutylene, butadiene, vinyl acetate, diethyl maleate or tetrafluoroethylene More recently, in another patent, Hammer has described the free radical initiated terpolymerization of CO and C2H with vinyl esters, vinyl ethers or methyl methacrylate 26Reaction temperatures of 180-200 °C and a combined pressure of 186 MPa were employed. Typically a CO QH4 olefin molar ratio of 10 65 25 was observed in the terpolymers. In other patents, Hammer 27,28) has described the formation of copolymers with pendant epoxy groups by the free radical initiated polymerization of CO, QH4, vinyl acetate and glycidyl methacrylate. Reaction conditions similar to those stated above were employed, and a typical CO C2H vinyl acetate glycidyl methacrylate molar ratio of 10 65 20 5 was observed in the product polymer. 

MC MDI MEKP MF MMA MPEG MPF NBR NDI NR OPET OPP OSA PA PAEK PAI PAN PB PBAN PBI PBN PBS PBT PC PCD PCT PCTFE PE PEC PEG PEI PEK PEN PES PET PF PFA PI PIBI PMDI PMMA PMP PO PP PPA PPC PPO PPS PPSU Methyl cellulose Methylene diphenylene diisocyanate Methyl ethyl ketone peroxide Melamine formaldehyde Methyl methacrylate Polyethylene glycol monomethyl ether Melamine-phenol-formaldehyde Nitrile butyl rubber Naphthalene diisocyanate Natural rubber Oriented polyethylene terephthalate Oriented polypropylene Olefin-modified styrene-acrylonitrile Polyamide Poly(aryl ether-ketone) Poly(amide-imide) Polyacrylonitrile Polybutylene Poly(butadiene-acrylonitrile) Polybenzimidazole Polybutylene naphthalate Poly(butadiene-styrene) Poly(butylene terephthalate) Polycarbonate Polycarbodiimide Poly(cyclohexylene-dimethylene terephthalate) Polychlorotrifluoroethylene Polyethylene Chlorinated polyethylene Poly(ethylene glycol) Poly(ether-imide) Poly(ether-ketone) Polyethylene naphthalate Polyether sulfone Polyethylene terephthalate Phenol-formaldehyde copolymer Perfluoroalkoxy resin Polyimide Poly(isobutylene), Butyl rubber Polymeric methylene diphenylene diisocyanate Poly(methyl methacrylate) Poly(methylpentene) Polyolefins Polypropylene Polyphthalamide Chlorinated polypropylene Poly(phenylene oxide) Poly(phenylene sulfide) Poly(phenylene sulfone)... 

Several copolymers of olefins with longer chain are used in practice. Among these, butyl rubber is probably the most commonly utilized. This material is a copolymer of isobutylene with small amounts of isoprene (1-6% wt). The amount of isoprene determines the extent of crosslinking. Pyrolysis of butyl rubber generates mainly products similar to those found in the pyrolysis of poly(isobutylene) including monomer, dimer, up to hexamers, depending on the pyrolysis temperature [135-137]. Besides the... 

The extension of fhis novel chain transfer event to higher molecular weight a-olefins has enabled us, and ofhers, to make unique poly(norbornene) block copolymers [44]. Examples of fhe diversity of this chain transfer chemistry are given in Fig. 4.15 where chain transfer to efhylene, allylglycidyl ether, isobutylene, cyclo-... 

Radiation induced copolymerization of hexafluoroacetone xcith a-olefins has been done over a broad temperature range. From these experiments, it was confirmed that ethylene can be copolymerized below its critical temperature to give an alternating copolymer. A radical mechanism is involved at relatively high temperatures below —10°C, the mechanism has been confirmed to be ionic and may be cationic. Propylene can be copolymerized in a way similar to that of ethylene however, the rate of copolymerization was much slower. Isobutylene did not copolymerize with hexafluoroacetone at 0°C. A 1 2 adduct compound was obtained as the main product. At low temperatures, copolymerization proceeds to some extent. 

Preparations of macro-initiators or telechelic polymers by cationic methods have been executed primarily by polymerizing isobutylene in the presence of a co-initiator that also functions as a chain transfer agent. A typical reaction sequence is shown in Scheme 1, outlining the synthesis of difunctional polyisobutylene (PIB), which is then used to initiate the polymerization of a-methyl styrene (ffi-MS) to produce an A-B-A type block copolymer. By similar methods, polyisobutylenes with phenol, phenyl, cyclopentadiene, and olefin termini have been synthesized. 

There has been a slight increase in activity in this area compared with that in the previous two year period. For the polymeric esters of acrylic, methacrylic acids, and related polymers the simplest reaction, apart from thermal depolymerization, is hydrolysis, and one or two papers on this subject have appeared. One of these concerns a comparison of the kinetics of hydrolysis of a number of methacrylate esters and a further two deal with the formation of copolymers containing carboxylic acid functions. Methyl trifluoroacrylate forms alternating copolymers with cE-olefins (ethylene, propylene, isobutylene) and these are readily hydrolysed in boiling aqueous methanolic sodium hydroxide to yield hydrophilic fluoropolymers. Hydrolysis is reported to be nearly quantitative with no chain scission. An alternating copolymer is also formed by radical polymerization of maleic anhydride with A-vinyl succinimide. On hydrolysis this copolymer is... 

It was clearly shown that beta-pinene resins were equivalent to an alternating copolymer of isobutylene and cyclohexene units as proposed originally by Roberts and Day. Dipentene resin structure was shown to be compact and stiff by comparison of softening point and molecular weight. The determination of olefin content and model monomer studies showed a structure not of the type to be predicted by polymerization via the pendant olefin. The size difference and rigidity of these two types of terpene resins appear to be the outstanding properties which result in the predominant use of beta-pinene resins for pressure sensitive use and dipentene resins for hot melt use. 

The pendant olefin function can also be utilized as a monomer in copolymerization with other olefins. Data on this are generally lacking. The diethyl-aluminum chloride-titanium trichloride combination has been used to make a propylene-MA 1 copolymer with good adhesion.ASAs made from propylene, 1-butene, and isobutylene copolymerize with MA using radical initiation either neat or in solution. 

Maleic anhydride grafting (cont.) poly(styrene-co-divinylbenzene), 694 poly(styrene-co-isobutylene), 675, 689 poly(styrene-co-nfialeic anhydride), 676, 679 poly(vinyl acetate), 676, 694 poly(vinyl acetate-co-vinyl fluoride), 678 poly(vinyl alkyl ethers), 675, 679, 692, 701 poly(vinyl chloride), 683, 692, 693, 695, 702 poly(vinylidene chloride), 691 poly(vinyl toluene-co-butadiene), 689 radical—initiated, 459-462, 464-466, 471, 475, 476 radiation—initiated, 459, 461, 466, 471, 474 redox-initiated, 476 rubber, 678, 686, 687, 691, 694 to saturated polymers, 459-466, 475, 476 solvents used 460-463, 465, 466, 469, 474-476 styrene block copolymers, 679 tall oil pitch, 678, 697 terpene polymers, 679, 700 thermally-initiated, 462, 464-467, 469, 476 to unsaturated polymers, 459, 466-474 vapor-phase techniques, 464, 474, 475 to wool fibers, 476 Maleic anhydride monomer acceptor for complex formation, 207-210 acetal copolymerization, 316 acetone CTC thermodynamic constants, 211 acetone photo-adduct pyrolysis, 195, 196 acetylacetone reaction, 235 acetylenic photochemical reactions, 193-196 acrylamide eutectic mixtures, 285 acylation of aromatic acids, 97 acylation of aromatics, 91, 92 acylation of fused aromatics, 92, 95, 97, 98 acylation of olefins, 99 acylation of phenols, 94-96 acylic diene Diels-Alder reactions, 104-111, 139 addition polymer condensations, 503-505 adduct with 2-cyclohexylimino-cyclopentanedi-thiocarboxylic acid, 51 adducts for epoxy resins curing, 507-510 adduct with 2-iminocyclopentanedithiocarboxylic acid, 51... 

Radicalic polymerized block copolymers containing poly(isobut-ylene) and poly(p-chlorostyrene) have been described as compatibilizers (40). Similarly, copolymers containing poly(isobutylene) and p-ferf-butylstyrene are useful compatibilizers for olefinic elastomers (2). 

The percent cyclization in polymer [81] was 92-95% as determined by nuclear magnetic resonance spectroscopy. The residual unsaturation was due to the presence of structures [82] and [83]. The formation of structure [83] is favored since Ziegler catalysts polymerize monosubstituted olefins preferentially. A copolymer possessing a higher proportion of [82] was favored on cationic polymerization (BF3/CH2CI2, -70°C). The formation of structure [82] in this instance is due to the similarity of the methylene double bond in the monomer with that in isobutylene. The latter polymerizes readily on cationic initiation. 

---