Base-catalyzed polymerization of maleimide and some derivatives and related unsaturated carbonamides

Basic catalysts in dimethylacetamide solution initiated the polymerization of maleimide to yield a low molecular weight polymer which has a copolymer structure. Approximately 75–85% of the recurring units are formed by hydrogen transfer and 15–25% by vinyl polymerization, as shown by hydrolysis, to yield aspartic acid on the one hand and ammonia and polymaleic acid on the other. Several maleimide derivatives have been prepared, but none has given a high molecular weight polymer by basic catalysis. Some unsaturated carbonamides such as p-vinylbenzamide, mono-N-acrylyl-hexamethylenediamine, and mono-N-acrylyl-p-phenylenediamine have been synthesized and polymerized by basic catalysts. Polymers with low molecular weights were obtained, but the complete structures of all these polymers were not established.     

Synthesis and study of polymerization and copolymerization of some oligounsaturated esters—V

A number of oligoacetylenic acrylates have been synthesized and characterized. The i.r. as well as the physical and chemical properties show the probable formation of oligomers possessing a proposed structure. The oligomers undergo further reaction in the presence of peroxide initiators to give crosslinked products. The i.r. spectra of the crosslinked products show that the oligomers undergo addition polymerization on the terminal double bonds. The triple bond in these oligomers is relatively unreactive under the conditions of polymerization, while that in the glycolic residue is reactive to a certain extent, as indicated by the higher per cent conversion of the oligomers having such unsaturated glycolic residue.Copolymerization of various oligoacetylenic acrylates, methacrylates and esters with terminal allylic group with styrene give crosslinked products. The polymers and copolymers are pale yellow in colour, glassy, insoluble in organic solvents and infusible; the copolymers were more rigid than the homopolymers. The volume shrinkage of various oligomers during polymerization lies between 5 and 13 per cent.     

Synthesis,polymerization, and copolymerization of lactam-substituted styrenes

Four new substituted styrene derivatives carrying lactam rings (2-pyrrolidone or 2-piperidone) in para position have been synthesized, namely 4-(2-oxo-3-methylene-pyrrolidinyl)styrene, 4-(2-oxo-3-methylene-piperidinyl)styrene, 4-(p-styryl)-2-pyrrolidone, and 4-(p-styryl)-2-piperidone. Their homopolymerization and copolymerization with styrene, methyl methacrylate, and acrylic acid have been considered. By ring opening of the side lactam groups, the homopolymers are transformed into the corresponding poly aminocarboxylic acids.     

Anionic polymerization and copolymerization of p-bromostyrene

Monodispersed poly(4-bromostyrenes) (PBs) and their block copolymers with styrene, isoprene, and 3-methylbutene were prepared and characterized by GPC and NMR. Polystyryl and α-methylstyryl carbanions act as effective initiators of the anionic polymerization of Bs in THF. The undersirable side reactions, due to thermally or photochemically induced decomposition of the bromostyryl carbanions, PBs^?, may be eliminated by conducting the reaction at ?78°C and in the dark. Under such conditions, the rate constant of propagation, k_p (?78°), is 1.5 × 10³ M^?1 s^?1. Radical anions, \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm Bs}^{\mathop - \limits_ \cdot} $\end{document}, formed as result of electron transfer from sodium naphthalenide to Bs, may eject spontaneously bromine ions. This step and reactions involving the respective phenyl radicals compete at ?78°C with the addition steps leading to polymer formation. Electron affinity of Bs seems to be much higher than that of styrene or isoprene, and PBs^? carbanions do not add to the latter monomers. Addition of Bs to polyisoprenyl carbanions leads to formation of the BsIBs block copolymers. BsIBs, prepared in THF, may be converted by preferential hydrogenation of the 1–2 adducts into block copolymers of Bs with poly(2-methylbutene) and isoprenyl segments. The effectiveness of Bs as a flame retarding constituent of polymeric systems seems to be much more pronounced when it is incorporated in a “block” than in a random fashion. A considerably larger fraction of PBs is required to achieve the same LOI value when the respective homopolymers are blended. Spatial distribution of the easily charred microdomains in the block copolymers is believed to be responsible for this phenomenon.     

Anionic polymerization and copolymerization of acrylophenone

The n-butyllithium-initiated polymerization of a mixture of acrylophenone (AP) and styrene produces only poly(AP), indicating that a chain ending in an AP enolate ion is not sufficiently nucleophilic to add to styrene. Radical copolymerization of AP and styrene yields a polymer containing 65% AP (at 41% conversion). In contrast, lithium dispersion-initiated polymerization of AP and styrene produces a product containing 50–99% AP, depending upon conversion. This observation is discussed in terms of current knowledge concerning alkali metal-initiated polymerization.     

PtCl2-mediated cycloisomerization of unsaturated propargylic carboxylates

The PtCl₂-mediated cycloisomerization of unsaturated propargylic carboxylates yields differently functionalized bicyclo[4.1.0]heptane enol esters from moderate to good yield, in a very diastereoselective manner. We have prepared and submitted to PtCl₂-catalyzed cycloisomerization a series of differently substituted hept-1-en-6-ynes with different O-acyl (acetyl, trichloroacetyl, 3,4,5-trimethoxybenzoyl, etc.) protecting groups at propargylic positions, investigating also the effect of the geometry at the double bond, as well as the effect of the number of substituents at the alkene moiety. As a result, we have found that the O-acetyl migrating group is the best one in terms of simplicity and chemical yields. In this reaction we have isolated mixtures of compounds formed by minor 1-acetoxy-allenes and major bicyclo[4.1.0]heptane derivatives. Major products are the result of a sequential process involving steps of cycloisomerization plus cyclopropanation, followed by acyl migration. The basic methanolysis (K₂CO₃, MeOH) of these intermediates gave mixtures of cis and trans-caran-2-ones. This two-step protocol (cycloisomerization plus basic methanolysis) for the syntheses of α,β-unsaturated cyclopropyl ketones constitutes a synthetic alternative to the usual unfriendly, intramolecular cyclopropanation of unsaturated α-diazocarbonyl derivatives. The formation of these bicyclo[4.1.0]heptane derivatives is a simple, but efficient entry into the skeleton of the ‘carane’ family of natural products.     

Preparation and polymerization of some N-(dialkylaminoalkyl)acrylamides

A series of N-(dialkylaminoalkyl)acrylamides was synthesized by reductive amination of N-(1,1-dimethyl-3-oxobutyl)acrylamide (diacetone acrylamide) and by the reaction of either an alkenylamine or an amino alcohol with acrylonitrile. These monomers homopolymerize and copolymerize readily to form high molecular weight products. The solubility of the monomers and their homopolymers in water ranges from soluble to insoluble at room temperature. The insoluble materials can be quaternized readily to produce water-soluble products. The solubility of the homopolymers in water decreases with increasing temperature. Glass transition and decomposition temperatures of the homopolymers are reported.     

Anionic polymerization and copolymerization of S-methyl thiomethacrylate

S-Methyl thiomethacrylate (methyl thiolmethacrylate, MTMA) was polymerized with a variety of anionic initiators such as n-BuLi, octylpotassium, PhMgBr, and Et₂AlNPh₂ in toluene and THF. Stereoregularity of the polymer (PMTMA) was determined from the ¹H-NMR spectrum of poly(methyl methacrylate), which had been derived from PMTMA, because the α-methyl resonance in the ¹H-NMR spectrum of PMTMA was not satisfactorily solved owing to the overlap of pentad signals. The ¹³C-NMR spectrum of PMTMA also showed the splitting due to pentad sequences. Stereoregularity of PMTMA was always low compared with that of poly(methyl methacrylate), which was prepared under the same reaction conditions. MTMA was much more reactive than methyl methacrylate and methacrylonitrile in the copolymerization with n-BuLi in toluene and in THF at ?78°C. The lower stereoregulation of the polymerization of MTMA and the higher reactivity of MTMA were mainly ascribed to the higher resonance effect of MTMA.     

Emulsion polymerization and copolymerization of vinyl benzoate

Emulsion polymerization of vinyl benzoate and its copolymerization with vinyl acetate or styrene are described. The effect of the potassium persulfate initiator, and the sodium lauryl sulfate emulsifier concentration on the rate of vinyl benzote homopolymerization and the molecular weight of the polymers was determined. In copolymerization with vinyl benzoate, both comonomers, vinyl acetate and styrene, decrease the initial polymerization rate. With increasing amounts of styrene in the comonomer mixture the polymerization rate increases but with vinyl acetate an opposite effect is observed. Reactivity ratios of copolymerizations were determined. For the vinyl benzoate [M₁]-styrene [M₂] comonomer system a r₁ = 0.03 and a r₂ = 29.58 and for vinyl benzoate [M₁]-vinyl acetate [M₂], a r₁ = 1.93 and a r₂ = 0.20 was obtained. From the vinyl benzoate-styrene reactivity ratios the Qe parameters were calculated.     

Anionic polymerization and copolymerization of 1-cyanobutadiene

A stereospecific synthesis of trans-1-cyanobutadiene is described. This monomer was polymerized by n-butyl lithium in toluene and in tetrahydrofuran to yield sparingly soluble products. In both solvents, the concatenation was predominatly trans-1,4 with a little cis-1,4 and 3,4 content. Copolymers with methyl methacrylate and methyl pentadienoate were prepared in the same way: the reactivity ratios differed markedly in the two solvents being more nearly ideal in tetrahydrofuran.     

Anionic polymerization and copolymerization of macromonomers: Kinetics,structure control

The present paper discusses the ability of macromonomers to undergo polymerization and copolymerization with acrylic and vinylic monomers. These macromonomers have been synthesized by classical deactivation reactions. Special interest was devoted to macromonomers fitted with polymerizable methylmethacrylate end-groups. The anionic homopolymerization of ω-methacryloyloxy-polystyrene macromonomers was studied in detail and the influence of the molar mass of the macromonomer on the apparent propagation constant was determined. The anionic homopolymerization of ω-methacryloyloxy poly(ethylene oxide) macro-monomers was also examined. In both cases, lithium chloride has to be added in order to reach a better control of the reaction. The dilute solution properties of these polystyrene polymacromonomers have been studied. Some preliminary attempts to apply that anionic homopolymerization of macromonomers to the preparation of “dumbbell” and “palmtree” polymers were presented.     

Preparation and polymerization of some vinyl ester amides of pinic acid

The preparation of vinyl 2,2-dimethyl-3-morpholinocarbonylcyclobutaneacetate, vinyl 2,2-dimethyl-3-piperidinocarbonylcyclobutaneacetate, and vinyl 2,2-dimethyl-3-di-n-butylaminocarbonylcyclobutaneacetate has been achieved by selective amination followed by vinyl interchange. Homopolymers and vinyl chloride copolymers containing 25 and 30 wt.-% of the vinyl esteramides were prepared and evaluated as nonrigid plastics. The vinyl esteramides incorporated in vinyl chloride copolymers did impart some plasticization, but their effect was far below the effect of added plasticizer to a vinyl chloride polymer.     

High-efficiency catalysts for norbornene polymerization, based on palladium carboxylates and boron trifluoride

Catalytic systems based on palladium carboxylates and boron trifluoride etherate were studied in the reaction of additive polymerization of nonbornene. The system Pd(OAc)₂ + 25BF₃OEt₂ exhibits a high activity, up to 154 100 kg of nonbornene per mole of Pd per hour.     

Radical copolymerization of N-vinylformamide with unsaturated carboxylic acids

Radical precipitative copolymerization of N-vinylformamide with acrylic and methacrylic acids in isopropanol at 60°C, with azobisisobutyric acid dinitrile as initiator, was studied. The conditional values of the relative reactivities were found: r ₁ = 0.068 ± 0.008 and r ₂ = 1.638 ± 0.025 for the N-vinylformamide-methacrylic acid copolymer and r ₁ = 0.15 ± 0.03 and r ₂ = 0.19 ± 0.09 for the N-vinylformamide-acrylic acid copolymer.     

Investigation of polymerization and copolymerization of 9-vinyl-anthracenes

The processes accompanying homopolymerization and copolymerization of 9-vinyl-anthracene (9-VA) and 9,10-vinyl-10-methyl-anthracene (9,10-VMA) were investigated. It was shown by electronic spectra that free-radical copolymerization of 9-VA and 9,10-VMA with methyl methacrylate yielded copolymers containing units of 9-methylene-9,10-dihydroanthracene structure. Acidic treatment of the copolymer solutions led to rearrangement of these units into 9,10-dialkylanthracene units incorporated into the main chain of the macromolecule. The position of anthracene-containing units in the chains was determined from fluorescence data.Free-radical isomerization copolymerization of 9-vinyl-anthracenes was used for obtaining model polymers with fluorescent marks incorporated into the backbone. These polymers are necessary for investigating intramolecular motion of macromolecules by the method of polarization of fluorescence.