Methyl monomer

Thus, 2-furfuryl vinyl ether 6a is extremely sensitive to cationic activation (16) because of its very pronounced nucleophilic character, but the polymerization is accompanied by some gel formation due to abundant alkylation of the furan rings pendant to the macromolecules. This structural anomaly is not encountered with the 5-methylated monomer 6b (16) precisely because electrophilic substitutions take place predominantly at C5 and are therefore impossible with this monomer. A similar difference of phenomenolo was observed with the 2-fiiryl oxiranes 4a and 4b (17). 

Morpholine-2,5-dione and its substituted analogue, 6-methylmorpholine-2,5-dione, appeared to undergo copolymerisation with lactide in the presence of the zinc oxide catalyst. The copolymers obtained were characterised by an increased content of a-hydroxyacid units. The copolymerisability of the unsubstituted monomer was comparable with that of lactide. However, the N-methylated monomer was much less susceptible than the unsubstituted one to copolymerisation with lactide [178],... 

Fig. 5.12. Rebek s softballs — dimeric self-assembling capsules. The cavity volume can be tuned by the length of the spacer introduced between the center piece and glycoluril binding sites of the monomers. The methylated monomer (bottom) is not able to form dimeric capsules. Several hydrogen bonding donors and acceptors (arrows) that are responsible for dimerization, are implemented in each building block. A computer-generated model of an example of a dimeric capsule is shown in the box. Right Typical guest molecules which can be encapsulated in the cavity.

Methylation analysis is the most important procedure for linkage analysis in carbohydrate-containing polymers (Lindberg, 1972). The procedure requires that all free hydroxyl in the oligo- or polysaccharide are etheri-fied. Following depolymerization of the methylated material, the monomers are separated, identified, and quantified. The free hydroxyl groups in the partially methylated monomers mark the position(s) at which the sugar residues were substituted. 

The methylated polymer is isolated and hydrolyzed, and the partially methylated monomers are characterized. Originally these derivatives were separated by partition chromatography on paper (Binkley, 1955), but this requires a relatively large amount of material. Subsequently the methylated monomers were separated by GLC as their methyl glycosides (Bishop, 1964), trimethylsilyl derivatives (Petersson and Samuelson,... 

This same synthetic approach was also used to create diamine ROMP monomers. The homopolymers were again selective for S. aureus, but not for E. coli. Since the diamine monomers closely resembled the methyl monomers in terms of hydrophobicity, copolymers of these two monomers were... 

Recently, Dai et al. (2008) reported obtaining PHAs containing methylated monomers [(3-hydroxy-2-methylbutyrate and (R)-3-hydroxy-2-methylvalerate) in Defluviicoccus vanus related glycogen-accumulating organisms grown under anaerobic conditions. These authors reported that an increase in the relative proportion of methylated monomers in the copolymer lowered its crystallinity to a considerable extent. 

High-resolution TGA has been applied to decomposition studies on polymethyl methacrylate (PMMA), ethylene-vinyl acetate copolymer and acrylonitrile-butadiene-styrene terpolymer [47-50]. The results obtained on a supposedly pure sample of PMMA homopolymer indicated that a small quantity of impurity, possibly unreacted methyl monomer or even polyethylene methacrylate, is present. Conventional TGA does not resolve this impurity. 

By contrast, in the system propionic acid d) - methyl isobutyl ketone (2), (fi and are very much different when y 1, Propionic acid has a strong tendency to dimerize with itself and only a weak tendency to dimerize with ketone also,the ketone has only a weak tendency to dimerize with itself. At acid-rich compositions, therefore, many acid molecules have dimerized but most ketone molecules are monomers. Acid-acid dimerization lowers the fugacity of acid and thus is well below unity. Because of acid-acid dimerization, the true mole fraction of ketone is signi-... 

The monomers used are second generation petrochemical products. The polymethacrylates are in fact copolymers based on methyl methacrylate and up to C20 molecular weight alcohol methacrylate. The properties of the additive are controlled based on the molecular ratio of these different monomers and their molecular weight. 

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 ... 

Place 25 g. of methyl methacrylate polymer (G.B. Diakon (powder). Perspex (sheet) U.S.A. Lucite, Plexiglass) in a 100 ml. Claisen flask, attach an efficient condenser e.g., of the double smface type) and distil with a small luminous flame move the flame to and fro around the sides of the flask. At about 300° the polymer softens and undergoes rapid depolymerisation to the monomer, methyl methacrylate, which distils over into the receiver. Continue the distillation until only a small black residue (3-4 g.) remains. Redistil the hquid it passes over at 100-110°, mainly at 100-102°. The yield of methyl methacrylate (monomer) is 20 g. If the monomer is to be kept for any period, add 0 -1 g. of hydro quinone to act as a stabiUser or inhibitor of polymerisation. 

Auto-association of A-4-thiazoline-2-thione and 4-alkyl derivatives has been deduced from infrared spectra of diluted solutions in carbon tetrachloride (58. 77). Results are interpretated (77) in terms of an equilibrium between monomer and cyclic dimer. The association constants are strongly dependent on the electronic and steric effects of the alkyl substituents in the 4- and 5-positions, respectively. This behavior is well shown if one compares the results for the unsubstituted compound (K - 1200 M" ,). 4-methyl-A-4-thiazoline-2-thione K = 2200 M ). and 5-methyl-4-r-butyl-A-4-thiazoline-2-thione K=120 M ) (58). 

A typical example is total monomers. 100 sodium stearate, 5 potassium persulfate, 0.3 lauryl mercaptan, 0.4 to 0.7 and water, 200 parts. In this formula, 75 parts of 1,3-butadiene and 25 parts of 4-methyl-2-vinylthiazole give 86% conversion to a tacky rubber-like copolymer in 15 hr at 45°C. The polymer contains 62% benzene-insoluble gel. Sulfur analysis indicates that the polymer contains 21 parts of combined 4-methyl-2-vinylthiazole (312). Butadiene alone in the above reaction normally requires 25 hr to achieve the same conversion, thus illustrating the acceleration due to the presence of 4-methyl-2-vinylthiazole. 

Polylmethyl Methacrylate). The monomer used for poly(methyl methacrylate), 2-hy-droxy-2-methylpropanenitrile, is prepared by the following reaction ... 

Poly (methyl Acrylate). The monomer used for preparing poly(methyl acrylate) is produced by the oxidation of propylene. The resin is made by free-radical polymerization initiated by peroxide or azo catalysts and has the following formula ... 

Figure 6.3 shows some data which constitute a test of Eq. (6.26). In Fig. 6.3a, Rp and [M] are plotted on a log-log scale for a constant level of redox initiator. The slope of this line, which indicates the order of the polymerization with respect to monomer, is unity, showing that the polymerization of methyl methacrylate is first order in monomer. Figure 6.3b is a similar plot of the initial rate of polymerization—which essentially maintains the monomer at constant con-centration—versus initiator concentration for several different monomer-initiator combinations. Each of the lines has a slope of indicating a half-order dependence on [I] as predicted by Eq. (6.26).

Figure 6.3 Log-log plots of Rp versus concentration which verify the order of the kinetics with respect to the constituent varied, (a) Monomer (methyl methacrylate) concentration varied at constant initiator concentration. [Data from T. Sugimura and Y. Minoura, J. Polym. Sci. A-l 2735 (1966).] (b) Initiator concentration varied AIBN in methy methacrylate (o), benzoyl peroxide in styrene ( ), and benzoyl peroxide in methyl methacrylate ( ). (From P. J. Flory, Principles of Polymer Chemistry, copyright 1953 by Cornell University, used with permission.)...

In cationic polymerization the active species is the ion which is formed by the addition of a proton from the initiator system to a monomer. For vinyl monomers the type of substituents which promote this type of polymerization are those which are electron supplying, like alkyl, 1,1-dialkyl, aryl, and alkoxy. Isobutylene and a-methyl styrene are examples of monomers which have been polymerized via cationic intermediates. 

Styrene and methyl methacylate have been used as comonomers in many investigations of copolymerization. Use the following listj of ri values for each of these copolymerizing with the monomers listed below to rank the latter with respect to reactivity ... 

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). 

Uses. The a2obisnitriles have been used for bulk, solution, emulsion, and suspension polymeri2ation of all of the common vinyl monomers, including ethylene, styrene vinyl chloride, vinyl acetate, acrylonitrile, and methyl methacrylate. The polymeri2ations of unsaturated polyesters and copolymeri2ations of vinyl compounds also have been initiated by these compounds. 

This monomer polymerizes faster ia 50% water than it does ia bulk (35), an abnormaHty iaconsistent with general polymerization kinetics. This may be due to a complex with water that activates the monomer it may also be related to the impurities ia the monomer (eg, acetaldehyde, 1-methyl pyrroHdone, and 2-pyrroHdone) that are difficult to remove and that would be diluted and partitioned ia a 50% aqueous media (see Vinyl polymers, A/-VINYLAMIDE POLYPffiRS). 

Poly(acrylic acid) and Poly(methacrylic acid). Poly(acryHc acid) (8) (PAA) may be prepared by polymerization of the monomer with conventional free-radical initiators using the monomer either undiluted (36) (with cross-linker for superadsorber appHcations) or in aqueous solution. Photochemical polymerization (sensitized by benzoin) of methyl acrylate in ethanol solution at —78° C provides a syndiotactic form (37) that can be hydrolyzed to syndiotactic PAA. From academic studies, alkaline hydrolysis of the methyl ester requires a lower time than acid hydrolysis of the polymeric ester, and can lead to oxidative degradation of the polymer (38). Po1y(meth acrylic acid) (PMAA) (9) is prepared only by the direct polymerization of the acid monomer it is not readily obtained by the hydrolysis of methyl methacrylate. 

It is also possible to iaterfere with the polymerization by attaching at the alpha positions either too many groups, or groups which are too bulky. Four chlorine atoms (12) or four methyl groups (13) seem to be sufficient to hinder the production of polymer. These crowded -xylylene monomers can be polymerized, but not through a VDP process. 

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). 

---