Monomers propylene monomer

Figure 7.14a illustrates the insertion of a propylene monomer into an edge vacancy in a crystal adjacent to an alkylated titanium atom. In Fig. 7.14b a cross-sectional view of the same site shows how the preferential orientation of the coordinated monomer is dictated by constraints imposed by the protuberances on the crystal surface. 

Manufacture of Monomers. The monomers of the greatest interest are those produced by oligomerization of ethylene (qv) and propylene (qv). Some olefins are also available as by-products from refining of petroleum products or as the products of hydrocarbon (qv) thermal cracking. 

The properties of polymers formed by the step growth esterification (1) of glycols and dibasic acids can be manipulated widely by the choice of coreactant raw materials (Table 1) (2). The reactivity fundamental to the majority of commercial resins is derived from maleic anhydride [108-31-6] (MAN) as the unsaturated component in the polymer, and styrene as the coreactant monomer. Propylene glycol [57-55-6] (PG) is the principal glycol used in most compositions, and (i9f2v (9)-phthahc anhydride (PA) is the principal dibasic acid incorporated to moderate the reactivity and performance of the final resins. 

ATBN - amine terminated nitrile rubber X - Flory Huggins interaction parameter CPE - carboxylated polyethylene d - width at half height of the copolymer profile given by Kuhn statistical segment length DMAE - dimethyl amino ethanol r - interfacial tension reduction d - particle size reduction DSC - differential scanning calorimetry EMA - ethylene methyl acrylate copolymer ENR - epoxidized natural rubber EOR - ethylene olefin rubber EPDM - ethylene propylene diene monomer EPM - ethylene propylene monomer rubber EPR - ethylene propylene rubber EPR-g-SA - succinic anhydride grafted ethylene propylene rubber... 

FIGURE 11.1S Diffused particles in natural mbber/ethylene-propylene monomer/rranj-polyoctylene rubber (NR-EPM-TOR) blend (a) are much smaller than in blends without TOR (b). (From Chang, Y.-W., Shin, Y.-S., Chun, H and Nab, C., J. Appl. Polym. Set, Ti, 749, 1999.)... 

Since alkoxy radicals are known precursors to chain scission in autoxidation (24), the "hot" alkoxy radicals formed as shown should undergo facile chain scission or fragmentation. The chain scission is illustrated for the alkoxy radical derived from either the ethylene or propylene monomer unit in EPM ... 

In the slurry process, propylene monomer is dissolved in a hydrocarbon diluent in which the polymerization process occurs. The polymerization products are either soluble (the highly atactic components) or insoluble. Both the insoluble and soluble components are collected and form separate product streams. The insoluble species form a slurry in the solvent, from which they are removed by centrifugation. The soluble, atactic component is removed with the solvent as another product stream. To separate the atactic polymer from the solvent, the solution is heated allowing the solvent to flash off, leaving the atactic polymer behind. Any un reacted monomer is degassed from the solution and recycled to the start of the polymerization process. 

SMPO [styrene monomer propylene oxide] A process for making propylene oxide by the catalytic epoxidation of propylene. The catalyst contains a compound of vanadium, tungsten, molybdenum, or titanium on a silica support. Developed by Shell and operated in The Netherlands since 1978. 

Polypropylene is produced from the monomer propylene by using the Ziegler-type catalyst as in case of polyethylene. 

The same basic propylene monomer induces many common properties and, unless otherwise specified, we will not make a distinction between the various subfamilies. Only the foams will be given special attention as they present particular properties due to their morphology ... 

Olefin epoxidation is an important industrial domain. The general approach of SOMC in this large area was to understand better the elementary steps of this reaction catalyzed by silica-supported titanium complexes, to identify precisely reaction intermediates and to explain catalyst deachvahon and titanium lixiviation that take place in the industrial Shell SMPO (styrene monomer propylene oxide) process [73]. (=SiO) Ti(OCap)4 (OCap=OR, OSiRs, OR R = hydrocarbyl) supported on MCM-41 have been evaluated as catalysts for 1-octene epoxidation by tert-butyl hydroperoxide (TBHP). Initial activity, selechvity and chemical evolution have been followed. In all cases the major product is 1,2-epoxyoctane, the diol corresponding to hydrolysis never being detected. 

Industrial companies have long-term strategies. For example, Exxon (now ExxonMobil) is the third largest chemical company in the United States. Some time ago, they made the decision to emphasize the ethylene and propylene monomers that are obtained from the petrochemical interests of ExxonMobil. Thus, ExxonMobil has a research emphasis on the commercialization of products from these monomers. The major materials made from ethylene and propylene are polymeric, either homopolymers or copolymers. Efforts include developing catalysts that allow the formation of polymeric materials from the ethylene and propylene monomers and the use of these catalysts to synthesize polymeric materials that have varying properties allowing their application in different marketplaces in society. 

A driving force for conversion of gasoline to polymeric materials is increased value in the products made from the polymers. The general trail is gasoline ethylene, propylene monomers raw polymers and copolymers —> finished products. 

Ethylene-propylene monomer (EPM) elastomers Aromatic nylons (aramids) (Nomex DuPont)... 

Figure 6 Relationship between catalyst symmetry and transition states of chain-migratory insertion of propylene monomer.

Bis(benzamidinate) zirconium catalysts (Figure 9, complexes F9-1 and F9-2) can polymerize propylene monomers into highly isotactic polypropylene (MAO up to 98% [mmmm, T = A9°C) at 25 °G in CH2CI2 under 9.2atm of propylene monomer, as expected from the G2-symmetric octahedral structure of the catalysts. The polymer-... 

Polypropylene (PP) is a semicrystalline commodity thermoplastic produced by coordination addition polymerization of propylene monomer [197]. Most frequently, stereospecific Ziegler-Natta catalysts are used in industrial processes to produce highly stereospecific crystalline isotactic (iPP) and syndiotactic (sPP) polymer with a small portion of amorphous atactic PP as a side product. Polymerization of non-symmetrical propylene monomer yields three possible sequences however, the steric effect related to the methyl side group highly favors the head-to-tail sequence. The occurence of head-to-head and tail-to-tail sequences produces defects along the PP chain [198]. Presence of such defects affects the overall degree of crystallinity of PP. 

With larger amount of propylene a random copolymer known as ethylene-propylene-monomer (EPM) copolymer is formed, which is a useful elastomer with easy processability and improved optical properties.208,449 Copolymerization of ethylene and propylene with a nonconjugated diene [EPDM or ethylene-propylene-diene-monomer copolymer] introduces unsaturation into the polymer structure, allowing the further improvement of physical properties by crosslinking (sulfur vulcanization) 443,450 Only three dienes are employed commercially in EPDM manufacture dicyclopentadiene, 1,4-hexadiene, and the most extensively used 5-ethylidene-2-norbomene. 

Other addition polymers are created by using different monomers. The only requirement is that the monomer must contain a double bond. The monomer propylene, for example, yields polypropylene, as shown in Figure 12.28. Polypropylene is a tough plastic material useful for pipes, hard-shell suitcases, and appliance parts. Fibers of polypropylene are used for upholstery, indoor-outdoor carpets, and even thermal underwear. 

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