Comonomers condensation

Methyl Isopropenyl Ketone. Methyl isopropenyl ketone [814-78-8] (3-methyl-3-buten-2-one) is a colorless, lachrymatory Hquid, which like methyl vinyl ketone readily polymerizes on exposure to heat and light. Methyl isopropenyl ketone is produced by the condensation of methyl ethyl ketone and formaldehyde over an acid cation-exchange resin at 130°C and 1.5 MPa (218 psi) (274). Other methods are possible (275—280). Methyl isopropenyl ketone can be used as a comonomer which promotes photochemical degradation in polymeric materials. It is commercially available in North America (281). 

Free-radical copolymerizations have been performed ia bulb (comonomers without solvent), solution (comonomers with solvent), suspension (comonomer droplets suspended ia water), and emulsion (comonomer emulsified ia water). On the other hand, most ionic and coordination copolymerizations have been carried out either ia bulb or solution, because water acts as a poison for many ionic and coordination catalysts. Similarly, few condensation copolymerizations iavolve emulsion or suspension processes. The foUowiag reactions exemplify the various copolymerization mechanisms. 

The next step concerned the synthesis of the polyester-polyimide copolymers. Triblock copolymers have been prepared by a step-growth copolymerization of stoichiometric amounts of an aromatic diamine and dianhydride (e.g., PMDA and 3FDA, as depicted in Scheme 41a) added with the single oo-amino polyesters as chain end-cappers. Graft copolymers can be prepared as well. In this case, the diamine end-functionalized oligomeric macromonomers are copolymerized with the polyimide condensation comonomers (Scheme 41b). 

A new class of functional comonomers exemplified by acrylamidobutyraldehyde dialkyl acetals 1 and their Interconvertible cyclic hemlamidal derivatives 2 were prepared and their chemistry was Investigated for use In polymers requiring post-crosslInking capability. These monomers do not possess volatile or extractable aldehyde components and exhibit additional crosslinking modes not found with conventional am1de/forma1dehyde condensates, eg, loss of ROH to form enamides 9 or TO and facile thermodynamically favored reaction with diols to form cyclic acetals. 

The first three components were mixed at room temperature and heated at 65°C In a 250 ml round bottom flask equipped with a magnetic stirring bar, reflux condenser and Na blanket. The AIBN was then added to start the reaction. Monitoring of the unreacted free monomers (butyl acrylate and comonomer) was done by GLPC. Additional 10 mg amounts of AIBN were added as needed. The temperature was also Increased to 75 C to finish the polymerization. Host of the reactions took longer than 24 h to reduce the free monomer below 0.7%. A control BA homopolymer and copolymers with butoxymethylacrylamide (BNMA), 2 (R = Et AEP), acrylamidoacetaldehyde dimethyl acetal (AADMA), and N-ethyl-1 (Et-ABDA, 13) were prepared In this way. 

Table I shows a comparison of free film swell Index results as a function of crosslinker at a constant comonomer level (0.3 moles/kg of polymer). ABDA and AEP gave crosslinking performance Identical to a conventional crosslinker, BNMA. However, derivatives which cannot cycllze, either because the amide has an additional substituent, as In 13, or the chain connecting the amide to the blocked aldehyde Is too short, as In 14, did not exhibit efficient crosslinking. They also showed significant discoloration, presumably due to Increased aldol condensation relative to 1, 2, or BNMA.

The only report on chemoenzymatic synthesis of branched polymers is from Peelers et al. [58], Heterotelechelic PCL macroinimer was synthesized in a one-pot enzymatic procedure by using 2-hydroxyethyl a-bromoisobutyrate as a bifunctional initiator. A polymerizable endgroup was introduced by subsequent in sim enzymatic acrylation with vinyl acrylate. Synthesis of branched polymers by self-condensing ATRP of the macroinimers was successfully conducted with and without the addition of MMA as a comonomer. 

Polycondensates with the Ligand as a Comonomer. Metal-bearing polycondensates in which the ligand moiety alone or in combination with the coordinated metal ions form one of the backbone comonomers are exemplified by the following polymers reported by Wudl et al [48], Biswas and Mazumdar [49, 50] and by Takahashi et al. [51] in the synthesis of organotin polymer by a similar condensate (Figs. 20, 21). 

Ethylene glycol in the presence of an acid catalyst readily reacts with aldehydes and ketones to form cyclic acetals and ketals (60). 1,3-Dioxolane [646-06-0] is the product of condensing formaldehyde and ethylene glycol. Applications for 1,3-dioxolane are as a solvent replacement for methylene chloride, 1,2-dichloroethane, 1,1,1-trichloroethane, and methyl ethyl ketone as a solvent for polymers as an inhibitor in 1,1,1-trichloroethane as a polymer or matrix interaction product for metal working and electroplating in lithium batteries and in the electronics industry (61). 1,3-Dioxolane can also be used in the formation of polyacetals, both for homopolymerization and as a comonomer with formaldehyde. Cyclic acetals and ketals are used as protecting groups for reaction-sensitive aldehydes and ketones in natural product synthesis and pharmaceuticals (62). 

In other examples, compounds in which a metal atom is already coordinated in a molecule can be used as a comonomer in an addition polymerization. Two examples involve the ferrocenes discussed in Chapter 6. The vinyl ferrocene molecule is shown in 7.14, and a similar vinyl manganese complex in 7.15.30 An alternative approach involves condensation polymerization. For example, if the R group in the ferrocene unit shown in 7.16 contains a hydroxyl group, it can be copolymerized with a diacid chloride. If it is an acid chloride, it can be copolymerized with a diamine. (This type of polymer is called a heteroannular chain if only one of the rings in the repeat unit is in the backbone, the polymer is called homoannular.)7 Similarly, the titanium complex shown in 7.17 is copolymerized with diacids or diols.30 Numerous other examples involving ferrocenes are discussed in Chapter 6. 

Determination of R r and rA batch polymerization of MMA-MAA comonomers afXcarried out for the determination of Rpmax anc reactivity ratios. The same procedure described in the batch process was used for this purpose except that the reaction vessel was a round bottom flask equipped with agitation, a nitrogen gas inlet, an outlet for taking samples, and a condenser. 

Strictly speaking, condensation polymers such as polyesters could be considered to belong to this category. Also polyketone ( Carilon ) would be a strictly alternating copolymer, if the regularity would not have been disturbed by a third comonomer, propylene. 

It has been reported that the effectiveness of copolymerized DOPO-type monomers can be further improved if the alcohol-amine derivatives of DOPO, for example, Structure 5.11, are used rather than similar structures not containing nitrogen.30 Of the FR fibers based on P-containing comonomers, it has been found that those based on Structure 5.10 are more hydrolytically stable, presumably because the P-containing group is in a cyclic structure and also should the hydrolysis of the P-0 bond occur, it will not lead automatically to a marked reduction in molecular weight.31 All the P-modified PETs appear to be subject to both the vapor-and condensed-phase mechanisms of flame retardance, with the former predominating.32 33... 

Another focal point for glycerol utilization has been in the synthesis of condensation polymers by esterification of glycerol with difunctional comonomers such as aliphatic dicarboxylic acids. In the past, monomers such as glycidol (Sunder et al, 1999), which is a highly reactive epoxide, or cis-1,3-0-benzylideneglycerol (Carnahan and Grinstaff,2001) were used as the glycerol-... 

The latent heat of the polymer solution leaving the reactor is used to flash off the solvent, unconverted ethylene and light comonomers in flash vessel (2). Vapors from this vessel are condensed in an overhead-system (3) and recycled back to the reactor feed without purification. 

Features - particles of growing polymer form in fluidized bed - catalyst residence time 2-4 hours - morphology and psd of catalyst are important - previously (pre-1990s) restricted in range of comonomer that could be used because of emergence of "condensed" mode operation, a wide range of comonomers may now be used... 

In the 1990s, an improvement for the gas phase process was developed called "condensed mode" operation of Unipol reactors (12). This technique greatly expanded capacity of gas phase reactors and product capability by making it more practical to use higher alpha-olefin comonomers such as octene-1. 

The polar-condensation linkage Is advantageous as a site for breakdown and (potential) controlled release of moieties derived from either or both the comonomers. 

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