Alkyl vinyl ether-maleic anhydride

Besides vinyl acetate monomer, three other components are neeessary to earry out an emulsion polymerization water, an emulsifier and/or a proteetive eolloid, and a water-soluble initiator. Most commonly, anionic long-chain alkyl sulfonates are used as surfactants in amounts up to 6%. Studies have shown that the rate of polymerization is dependent on the amoimt of emulsifier present, with the rates inereasing as the amoimt of emulsifier is increased up to a certain point and then falling olF as free-radieal ehain transfer to the surfaetant beeomes a serious competing side reaetion [240]. In general, surfactants are used in eombination with a protective colloid. Especially useful as protective colloids are poly(vinyl alcohol), hydroxyethyl cellulose, alkyl vinyl ether-maleic anhydride and styrene-allyl alcohol copolymers, and gum arable. Water-soluble initiators, particularly potassium persulfate, alkali peroxydisulfates, hydrogen peroxide, and various redox systems, are most commonly used. 

C.W. Woodruff, G.E. Peck, and G.S. Banker, Dissolution of alkyl vinyl ether-maleic anhydride copolymers and esther derivatives,/. Pharm. Sci., 61 (12), 1916-1921,1972. 

A.4. Alkyl Vinyl Ether-Maleic Anhydride Copolymer Patents A. 5. Vinyl Acetate-Maleic Anhydride Copolymer Patents A.6. Patents on Maleic Anhydride Copolymers with Miscellaneous Monomers... 

Table A.4. Alkyl Vinyl Ether-Maleic Anhydride Copolymer Patents... 

Polymeric anhydrides can be prepared by the above techniques and are beginning to find various commercial uses. These are the styrene-maleic anhydride copolymers and the alkyl vinyl ether-maleic anhydride copolymers. The use of maleic acid or itaconic acid is widely used in the polymer field to give copolymers with anhydride functionality. 

A recently developed version of the methacrylate resist polymer platform is based on the radical copolymerization of vinyl ether, maleic anhydride, and acrylate monomers bearing appropriate functional groups. Linear or cychc alkyl vinyl ethers have been copolymerized with methacrylates bearing deprotectable ester groups (XXXV). 

The refined grade s fastest growing use is as a commercial extraction solvent and reaction medium. Other uses are as a solvent for radical-free copolymerization of maleic anhydride and an alkyl vinyl ether, and as a solvent for the polymerization of butadiene and isoprene usiag lithium alkyls as catalyst. Other laboratory appHcations include use as a solvent for Grignard reagents, and also for phase-transfer catalysts. 

The polymerization of alkyl vinyl ethers is of some commercial importance. The homopolymers, which can be obtained only by cationic polymerization, are useful as plasticizers of other polymers, adhesives, and coatings. (The copolymerization of vinyl ethers with acrylates, vinyl acetate, maleic anhydride, and other monomers is achieved by radical polymerization but not the homopolymerizations of alkyl vinyl ethers.)... 

Alkyl monoesters of poly(vinyl methyl ether-maleic anhydride) (PVM-MA) are bioerodible acidic polymers that are used to control drug release. In biological fluids with poor buffering capacity, drug release from the polymers and their dissolution are slowed owing to the lower pH on the polymer surface. We studied whether the release of timolol from matrices of monoisopropyl ester of PVM-MA in vitro and in vivo in rabbits eyes could be affected by disodium phosphate in the matrices. Addition of disodium phosphate to the matrices doubled the release rate of timolol in vitro, but it did not affect the bulk pH of the dissolution medium. On the basis of the timolol concentrations in the tear fluid and in systemic circulation, disodium phosphate seems to accelerate drug release in vivo also. Disodium phosphate probably affects the rate of dmg release by increasing the microenvironmental pH on the polymer surface. 

Bioerodible alkyl monoesters of poly(vinyl methyl ether-maleic anhydride) (PVM-MA) (Fig. 1) can be used to control drug release. Being acidic, ionizable polymers the pH of the disolution medium affects the rate of polymer dissolution [1]. 

A.Urtti, Pilocarpine release from matrices of alkyl half-esters of poly( vinyl methyl ether/maleic anhydride), Int. 

The interactions of a-olefins or styrene with sulfur dioxide (16) or a-olefins (24, 58, 78), frans-stilbene (64), styrene (1,63), p-dioxene (52), 2,2-dimethyl-l,3-dioxole (17), or alkyl vinyl ethers (1, 63) with maleic anhydride yield charge transfer complexes which are stable and generally readily detectable either visually or by their ultraviolet absorption spectra. However, under the influence of a sufficiently energetic attack in the form of heat or free radicals, the diradical complexes open, and alternating copolymers are formed. 

Another electron-rich monomer, vinyl ether, has been employed for radical copolymerization with electron-deficient maleic anhydride to yield a VEMA system (Fig. 76) [274]. Linear or cyclic alkyl vinyl ethers have been used in conjunction with deprotectable alicylic (meth)acrylate. The replacement of NB... 

In studies on hydrophobic interactions and conformational transitions of selected hydrolyzed maleic anhydride-alkyl vinyl ether copolymers (I, 2), we found that under certain conditions neutralization by base caused phase separation in aqueous solutions of the hexyl and octyl copolymers. Both the hexyl and octyl copolymers are insoluble at low pH and require partial neutralization by a base for complete dissolution. Under certain conditions, these copolymers will again precipitate as their degree of neutralization is raised with more base. Insolubility at low pH has been reported for other polyacids (3, 4). However, the phase separation at high pH contradicts the wealth of data indicating that neutralization increases the water affinity of polyacids. 

Examples of various coupling agents in order of appearance are maleic anhydride (59), alkyl vinyl ether (65), acrylic or methacrylic acid (67), vinyl... 

Alternating copolymers ( interpolymers ) of maleic anhydride and alkyl vinyl ethers are prepared by free radical polymerization in solvent, non-solvent or bulk media Products prepared from ethyl-, butyl-, hexyl-, and octyl-, and decyl- vinyl ethers are described in Table I. The decyl-copolymer was prepared by Dr A. W. Schultz. A methyl-copolymer ( Gantrez AN General Aniline and Film Corp.), not described in Table I, was included in some studies. Molecular weight estimates were... 

High-molecular-weight A-substituted maleimides have been prepared and used as polymeric food antioxidants which can achieve the desired gastrointestinal nonabsorption. A-(3,5-Di-t-Bu -hydroxyphenyl)maleimide was prepared in two steps (a) formation of 2,6-di-t-Bu-4-aminophenol either from 2,6-di-(-Bu-phenol by nitration followed by reduction, or from 4-aminophenol by alkylation, (b) amida-tion of maleic anhydride with the 2,6-di-t-Bu-4-aminophenol followed by dehydration. The nonabsorbable poly(A-(3,5-di-t-Bu-4-hydroxyphenyl)maleimide)s were prepared from the monomeric maleimides by free radical homo- and copolymerization with comonomers of alkyl vinyl ethers (Scheme 5.5) [43]. 

Mixtures of hydrocoUoidal gelling agents in an aqueous medium have also been employed as water-soluble or water-dispersible additives to provide gels having solids-suspending properties. Such mixtures include a mixture of hydroxypropyl-cellulose and poly(l-alkene-maleic anhydride) as poly(isobutylene-co-maleic anhydride), and a blend of hydroxypropylcellulose and poly(alkyl vinyl ether-co-maleic anhydride) as poly(methyl vinyl ether-co-maleic anhydride) [91]. 

Maleic copolymers, especially those with alkyl vinyl ethers, were used in drug formulations where only physical interactions occurred between the polymer matrix and the therapeutic agent. The polymers used in the formulations should be biocompatible, nontoxic, and should not induce allergic or pyrogenic reactions. Poly(maleic anhydride-co-methyl vinyl ether) (MA-MVE) is such a polymer, being approved by the FDA. Commercialized as Gantrez AN, MA-MVE copolymer is used as pharmaceutical excipient due to its bio/mucoadhesion and excellent film-forming properties [137]. 

Free-radical copolymerization of alkyl vinyl ethers has been carried out with the following typical monomers acrylic acid (bulk and emulsion) [39,40], acrylonitrile (emulsion) [26,27], acrylic esters (emulsion) [41], methyl methacrylate (bulk) [42], maleic anhydride (solution) [43], vinyl acetate (bulk and emulsion) [27,44,45], and vinyl chloride (emulsion) [26, 37,46]. The properties of these and other copolymers are described in a technical bulletin by General Aniline Film Corporation [38]. 

Other monomers that copolymerize with alkyl vinyl ethers are vinyl ketones [47], acrolein diacetate [48], acrylamide [49], alkoxy 1,3-butadienes [50], butadiene [51], chloroprene [52], chlorotrifluoroethylene [53], tri-and tetrafluoroethylene [54], cyclopentadiene [55], dimethylaminoethyl acrylate [56], fluoroacrylates [57], fluoroacrylamides [58], A-vinyl car-bazole [59,60], triallyl cyanurate [59,60], vinyl chloroacetate [61,62], N-vinyl lactams [63], A-vinyl succinimide [63], vinylidene cyanide [64, 65], and others. Copolymerization is especially suitable for monomers having electron-withdrawing groups. Solution, emulsion, and suspension techniques can be used. However, in aqueous systems the pH should be buffered at about pH 8 or above to prevent hydrolysis of the vinyl ether to acetaldehyde. Charge-transfer complexes have been suggested to form between vinyl ethers and maleic anhydride, and these participate in the copolymerization [66]. Examples of the free-radical polymerization of selected vinyl ethers are shown in Table IV. 

Terpolymer of maleic anhydride 1 Cl-C5-alkyl vinyl ethers and a Ci2 C,4 alpha olefin and cross-linked products have recently been reported [70]. A similar report appears using isobutylene as the olefin [71]. The latter for polymers have reported to be useful as denture adhesives. 

Addition of maleic anhydride to poly(alkyl vinyl ethers) [93]. 

Strauss UP, Vesnaver G (1975) Optical probes in polyelectrolyte studies. 2. Fluorescence-spectra of dansylated copolymers of maleic-anhydride and alkyl vinyl ethers. J Phys Chem 79 (22) 2426-2429. doi 10.1021/j 100589a017... 

Maleic anhydride has been copolymerized in benzene solution with seven different optically active alkyl vinyl ethers, having an asymmetric carbon atom at the a, (3, y, or S position of the alkyl residue (Table Chemical... 

Endo adducts are usually favored by iateractions between the double bonds of the diene and the carbonyl groups of the dienophile. As was mentioned ia the section on alkylation, the reaction of pyrrole compounds and maleic anhydride results ia a substitution at the 2-position of the pyrrole ring (34,44). Thiophene [110-02-1] forms a cycloaddition adduct with maleic anhydride but only under severe pressures and around 100°C (45). Addition of electron-withdrawiag substituents about the double bond of maleic anhydride increases rates of cycloaddition. Both a-(carbomethoxy)maleic anhydride [69327-00-0] and a-(phenylsulfonyl) maleic anhydride [120789-76-6] react with 1,3-dienes, styrenes, and vinyl ethers much faster than tetracyanoethylene [670-54-2] (46). 

The data presented here constitute part of the results attained in the development of a research project funded by the European Community (EC) and performed in cooperation with three independent European companies [6]. Hybrid polymeric materials based on intimate blends of human serum albumin (HSA), alkyl hemiesters of alternating copolymers of maleic anhydride (MAn), and vinyl ethers of monomethoxyoligoethylene glycols (PEGVE) were selected as biocompatible matrices for the formulation of the nanoparticles. 

The preparation and characterization of alternating copolymers of Maleic anhydride (MAn) and poly (ethylene glycol-vinyl ether) as well as their chemical conversions to provide various alkyl hemiesters (Scheme 1) have been described elsewhere [7]. The matrices are quoted as PAMm z, where m represent the number of oxyethylene units in R and n the number of carbon atoms in R. Human serum albumin (HSA) was provided by Isti-tuto Sierovaccinogeno Italiano SpA, Italy. 

According to most sources, the homopolymer of the vinyl alkyl ethers react to ionizing radiation predominantly by cross-linking 18). It is safe to conclude that maleic anhydride has contributed a predominance of chain scissioning to the copolymer and that, if cross-linking does take place, it is in very small proportion. 

The processing properties of poly(vinyl chloride) has been improved by copolymerizing vinyl chloride with a small amount of vinyl alkyl ether. Copolymers of vinyl alkyl ethers and maleic anhydride arc used as water soluble thickeners, paper additives, textile assistants and in cleaning formulations. 

Attempts have been made over time to improve the physical properties of novolacs. The use of phenol formaldehyde resins prepared in alkaline medium in photoresist compositions is mentioned in a Kalle Co. AG patent. The use of polyvinyl ethers in combination with novolacs to impart stickiness and plasticization action to the latter was patented by Christensen. Steinhoff, Isaacson, and Roelants of the Shipley Company mention the use of vinyl ethers in a patent on roller coating. Lower alkyl polyvinyl ethers, such as methyl, ethyl, butyl, and isobutyl, are added to novolac resins to improve coating flexibility and adhesion to metal surfaces as well as to improve resistance to mildly alkaline solutions. The use of styrene, methyl styrene, and styrene-maleic anhydride copolymers in combination with novolac was mentioned in several patents of both Shipley and Kalle Co. AG. When novolac is copolymerized with maleic anhydride, a resin that is readily soluble in alkaline solutions is obtained. ... 

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