Acetone polymers

Under argon, to a mixture of 2,5-dichlorobenzophenone (2.5 g, 10 mmol), zinc (2.0 g, 30.6 mmol), NiCl2 (0.13 g, 1 mmol), PPh3 (1.04 g, 4 mmol), and bipyridine (01.6 g, 1.01 mmol) was added 30 mL DMF. The mixture was heated to 70°C and stirred at that temperature for 20 h. The reaction mixture was then dispersed into acetone. The solid was filtered and washed with 5% HC1 (3 times), water (3 times), and acetone. Polymer 57 was obtained in quantitative yield as a yellowish powder. GPC (polystyrene standards) Mw = 58,000. 

It is very well known that polymers of high commercial value are obtained from formaldehyde by addition polymerization of its carbon-oxygen double bond. Not so well known is the addition polymerization capability of the carbon-sulfur double bond, probably because none of the polymers so obtained has yet become commercially acceptable. However, the polymerization chemistry of the carbon-sulfur double bond has been the subject of a number of studies and these have defined the preparation and properties of polythioformaldehyde, polythio-acetone, polymers from a small number of higher thioketones, and polymers from fluorine analogs of thioaldehydes and thioketones. The monomers have great reactivity beyond polymerization, and their general chemistry has been discussed in earlier reviews (/, 2). 

Miscellaneous Acetone Contribution of acetone polymers to coextracted material. Capillary gas chromatography ... 

There are a few reports dealing with the coordination polymerisation of acetone in the presence of organometallic catalysts. Such a situation results from long-term instability of acetone polymers [283]. The polymerisation of acetone with metal alkyls such as triethylaluminium as catalysts has been reported [284,285] to produce polymers containing acetalic units (Table 9.3), which was confirmed by IR spectroscopy. 

A ganciclovir intravitreal implant (Vitrasert, Chiron Vision, Claremont, CA) that has been developed provides release of 4.5 mg ganciclovir from a PVA and ethyl-vinyl-acetone polymer pellet at approximately... 

The ultimate compressive strength of furfurol-acetone polymer concrete control samples is 65 MPa. The most intensive decrease in the strength of the samples stored in environments with humidity of 50% to 60% and 86% to 96%, starts with 110 days (Figure 1.6). 

Deformation properties of the furfurol-acetone polymer samples are reduced to a much greater extent. The modulus of elasticity of the polymer concrete samples starts to decrease noticeably (about 10% to 15%) at 50% to 95% humidity after just 150 days for the samples in water, a 30% reduction of the modulus has been observed after 50 days (Figure 1.7). After 350 days, the modulus of elasticity is reduced by 28% for the samples in the environment with 50% to 60% humidity, 46% in the medium with 85% to 95% humidity, and 67% for the samples stored in water. As this takes place, the trend of modules is not identical the modulus of elasticity of the first two series of samples trends downward over time, whereas for the samples in water, this tendency stopped after 6 months of exposure. 

Let s consider the reasons for decreases in the stress-strain parameters of furfurol-acetone polymer concrete in a wet environment. The process of water absorption by polymer concrete occurs in two ways by diffusion and absorption. The latter is associated with the presence of free benzene sulfonic acid, which is highly hygroscopic and absorbs moisture from the environment and thus increases... 

FIGURE 1.6 Dependence of ultimate compressive strength of furfurol-acetone polymer concrete samples on exposition time at humidity of environment 1 50%-60%, 2 85%-95%, 3 water immersion. (From Yu. Borisov, Yu. Potapov, O. Figovsky, D. Beilin, Water Resistance of the Polymer Concretes, /. Scientific Israel Advanced Technology 14, no. 3 (2012) 84-91. With permission.)... 

Liu WY, Liu RG, Li YX, Kang HL, Shen D, Wu M, Huang Y (2009) Self-assembly of ethyl cellulose-grayi-polystyrene copolymers in acetone. Polymer 50 211-217... 

Figure 16.4 AFM phase images of silicon substrates dip coated from a solution of PFDMS- -PMMA in acetone. Polymers (a) PFS5o- -PMMAn67, (b) PFSso- -PMMAsai, and after annealing in a vacuum at 160 °C for 24 h. Phase scale is 10°. (Reprinted with permission from I. Korczagin, M.A. Hempenius, R.G. Fokkink et aL, Self-assembly of poly(ferrocenyldimethylsilane-b-methyl methacrylate) block copolymers in a selective solvent, Macromolecules, 39, 2306, 2006. 2006 American Chemical Society.)...

CH =C(CH3)C02Me. Colourless liquid b.p. lOO C. Manufactured by healing acetone cyanohydrin with methanol and sulphuric acid. It is usually supplied containing dissolved polymerization inhibitor, on removal of which it is readily polymerized to a glass-like polymer. See acrylate resins. 

The action of sulphuric acid alone upon acetone cyanohydrin affords a-methylacrylic acid. The methyl methacrylate polymers are the nearest approach to an organic glass so far developed, and are marketed as Perspex (sheet or rod) or Dialcon (powder) in Great Britain and as Plexiglass and Luciie in the U.S.A. They are readily depolymerised to the monomers upon distillation. The constitution of methyl methacrylate polymer has been given as ... 

PROPENE The major use of propene is in the produc tion of polypropylene Two other propene derived organic chemicals acrylonitrile and propylene oxide are also starting materials for polymer synthesis Acrylonitrile is used to make acrylic fibers (see Table 6 5) and propylene oxide is one component in the preparation of polyurethane polymers Cumene itself has no direct uses but rather serves as the starting material in a process that yields two valuable indus trial chemicals acetone and phenol... 

Furfural reacts with ketones to form strong, crosslinked resins of technical interest in the former Soviet Union the U.S. Air Force has also shown some interest (42,43). The so-called furfurylidene acetone monomer, a mixture of 2-furfurylidene methyl ketone [623-15-4] (1 )> bis-(2-furfurylidene) ketone [886-77-1] (14), mesityl oxide, and other oligomers, is obtained by condensation of furfural and acetone under basic conditions (44,45). Treatment of the "monomer" with an acidic catalyst leads initially to polymer of low molecular weight and ultimately to cross-linked, black, insoluble, heat-resistant resin (46). 

Furfural—acetone resins have been used to form resin-aggregate mixtures referred to as organic concretes. Despite the reportedly excellent properties, there has been virtually no commercial use of such resins outside the former Soviet Union. The stmctures and polymerization mechanisms of these furfural—aldehyde—ketone polymers are discussed in a review (6). 

Polymer is separated from the polymerisation slurry and slurried with acetic anhydride and sodium acetate catalyst. Acetylation of polymer end groups is carried out in a series of stirred tank reactors at temperatures up to 140°C. End-capped polymer is separated by filtration and washed at least twice, once with acetone and then with water. Polymer is made ready for extmsion compounding and other finishing steps by drying in a steam-tube drier. 

With aldehydes, primary alcohols readily form acetals, RCH(OR )2. Acetone also forms acetals (often called ketals), (CH2)2C(OR)2, in an exothermic reaction, but the equiUbrium concentration is small at ambient temperature. However, the methyl acetal of acetone, 2,2-dimethoxypropane [77-76-9] was once made commercially by reaction with methanol at low temperature for use as a gasoline additive (5). Isopropenyl methyl ether [116-11-OJ, useful as a hydroxyl blocking agent in urethane and epoxy polymer chemistry (6), is obtained in good yield by thermal pyrolysis of 2,2-dimethoxypropane. With other primary, secondary, and tertiary alcohols, the equiUbrium is progressively less favorable to the formation of ketals, in that order. However, acetals of acetone with other primary and secondary alcohols, and of other ketones, can be made from 2,2-dimethoxypropane by transacetalation procedures (7,8). Because they hydroly2e extensively, ketals of primary and especially secondary alcohols are effective water scavengers. 

Acrylics. Acetone is converted via the intermediate acetone cyanohydrin to the monomer methyl methacrylate (MMA) [80-62-6]. The MMA is polymerized to poly(methyl methacrylate) (PMMA) to make the familiar clear acryUc sheet. PMMA is also used in mol ding and extmsion powders. Hydrolysis of acetone cyanohydrin gives methacrylic acid (MAA), a monomer which goes direcdy into acryUc latexes, carboxylated styrene—butadiene polymers, or ethylene—MAA ionomers. As part of the methacrylic stmcture, acetone is found in the following major end use products acryUc sheet mol ding resins, impact modifiers and processing aids, acryUc film, ABS and polyester resin modifiers, surface coatings, acryUc lacquers, emulsion polymers, petroleum chemicals, and various copolymers (see METHACRYLIC ACID AND DERIVATIVES METHACRYLIC POLYMERS). 

An example of a commercial semibatch polymerization process is the early Union Carbide process for Dynel, one of the first flame-retardant modacryhc fibers (23,24). Dynel, a staple fiber that was wet spun from acetone, was introduced in 1951. The polymer is made up of 40% acrylonitrile and 60% vinyl chloride. The reactivity ratios for this monomer pair are 3.7 and 0.074 for acrylonitrile and vinyl chloride in solution at 60°C. Thus acrylonitrile is much more reactive than vinyl chloride in this copolymerization. In addition, vinyl chloride is a strong chain-transfer agent. To make the Dynel composition of 60% vinyl chloride, the monomer composition must be maintained at 82% vinyl chloride. Since acrylonitrile is consumed much more rapidly than vinyl chloride, if no control is exercised over the monomer composition, the acrylonitrile content of the monomer decreases to approximately 1% after only 25% conversion. The low acrylonitrile content of the monomer required for this process introduces yet another problem. That is, with an acrylonitrile weight fraction of only 0.18 in the unreacted monomer mixture, the low concentration of acrylonitrile becomes a rate-limiting reaction step. Therefore, the overall rate of chain growth is low and under normal conditions, with chain transfer and radical recombination, the molecular weight of the polymer is very low. 

Polyesters. Polyesters containing carbonate groups have been prepared from this diol (see Polycarbonates) (99). Films of this polymer, formed from an acetone or ethyl acetate solution, exhibit exceUent adhesive properties. 

For small-scale preparation of samples for scientific studies, the precursor polymer may be dissolved in xylene at 80°C, followed by addition of the cation source. A gelled fluid is normally obtained immediately, and the ionomer is recovered as a powder by chopping the gel in a large excess of acetone using a laboratory blender. 

Solubility and Solvent Resistance. The majority of polycarbonates are prepared in methylene chloride solution. Chloroform, i7j -l,2-dichloroethylene, yy -tetrachloroethane, and methylene chloride are the preferred solvents for polycarbonates. The polymer is soluble in chlorobenzene or o-dichlorobenzene when warm, but crystallization may occur at lower temperatures. Methylene chloride is most commonly used because of the high solubiUty of the polymer (350 g/L at 25°C), and because this solvent has low flammabiUty and toxicity. Nonhalogenated solvents include tetrahydrofuran, dioxane, pyridine, and cresols. Hydrocarbons (qv) and aUphatic alcohols, esters (see Esters, organic), or ketones (qv) do not dissolve polycarbonates. Acetone (qv) promotes rapid crystallization of the normally amorphous polymer, and causes catastrophic failure of stressed polycarbonate parts. 

Structure and Crystallinity. The mechanical—optical properties of polycarbonates are those common to amorphous polymers. The polymer may be crystallized to some degree by prolonged heating at elevated temperature (8 d at 180°C) (16), or by immersion ia acetone (qv). Powdered amorphous powder appears to dissolve partially ia acetone, initially becoming sticky, then hardening and becoming much less soluble as it crystallizes. Enhanced crystallization of polycarbonate can also be caused by the presence of sodium phenoxide end groups (17). 

Film or fibers derived from low molecular weight polymer tend to embrittle on immersion ia acetone those based on higher molecular weight polymer (>0.60 dL/g) become opaque, dilated, and elastomeric. When a dilated sample is stretched and dried, it retains orientation and is crystalline, exhibiting enhanced tensile strength. The tensile heat-distortion temperature of the crystalline film is iacreased by about 20°C, and the gas permeabiUty and resistance to solvent attack is iacreased. 

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