Copolymerization of aryldiazomethanes

Several aryldiazoalkanes (M₂) have been copolymerized with phenyldiazomethane (M₁) in toluene-methanol solution at 40°C, namely, the p-chloro-, p-methoxy-, p-mesyl-o and -p-methyl-, 2,4- and 3,4-dichlorophenyldiazoalkanes, and the α- and β- naphthyl-diazoalkanes. The copolymerization parameters r₁ and r₂ have been evaluated. By plotting 1/r₁ against the Hammett σ values a negative ρ values was found equal to ?0.88. From cationic copolymerizations carried out at ?78°C in the presence of boron trifluoride-diethyl ether as catalyst a similar plot of 1/r₁ against σ gives a value of ρ equal to ?0.82. The negative sign and the agreement between these ρ values demonstrates the cationie mechanism of the methanol polymerization and copolymerization of aryldiazoalkanes.     

Copolymerization of trialkylvinylgermane

The polymerization of trimethylvinylgermane (TMGeV) with the use of γ-ray, radical, and ionic initiator was attempted, but homopolymer was not obtained. This monomer did not undergo polymerization by itself, but polymerized with high concentration of n-BuLi. Copolymerization of TMGeV with styrene (St) and methyl methacrylate (MMA) was carried out by using radical initiator. From the results obtained by the copolymerization, monomer reactivity ratios and Q–e values were obtained as follows: for the system St(M₁)–TMGeV (M₂), r₁ = 24.4, r₂ = 0.009, Q₂, = 0.0049, e₂ = 0.43; for the system MMA (M₁)–TMGeV (M₂), r₁ = 19.98, r₂ = 0.05; Q₂ = 0.037, e₂ = 0.43., The polymerizability of TMGeV is discussed on the basis of the Q and e values obtained.     

Copolymerization of styrene with N-vinylformamide and ethylene glycol dimethacrylate and characteristics of the formed particles

Emulsion and emulsifier-free emulsion polymerization of styrene, N-vinylformamide, and ethylene glycol dimethacrylate are investigated with the goal to form positively charged monodisperse submicron crosslinked particles. The effects of the monomer ratio, the type and concentration of the buffer salt, and the emulsifier concentration on the monomer conversion and on the shapes, size distributions, and surface characteristics of the formed particles are studied. It is shown that, in the surface layers, amino groups prevail over carboxylic groups. The total surface concentration of acidic and basic groups increases with the degree of crosslinking of particles and as a result of their subsequent surface hydrolysis.     

Copolymerization with Depropagation

Free-radical copolymerizations of styrene with α-methylstyrene and methyl methacrylate and of acrylonitrile with α-methylstyrene have been carried out in the approximate regions of the ceiling temperatures of α-methylstyrene and methyl methacrylate. A theoretical treatment of copolymerization emphasizing the thermodynamic reversibility of particular propagation reactions has been compared with a kinetic treatment of copolymerization which emphasizes penultimate unit effects on the same propagation reactions. The former is found to adequately describe experimental copolymer composition data over a wide range of temperatures and over the complete range of monomer feed composition.     

Copolymerization on matrices

By copolymerization of polyfunctional monomers (multimethacrylates) with styrene or p-cresyl methacrylate, copolymers containing ladder-type blocks were obtained. Fractionation of the products was carried out; molecular masses, intrinsic viscosities as well as the number of end-groups per polymer molecule were determined. It has been found that these copolymers are only slightly branched; however more than 90% of multimethacrylate units react along the matrix (p-cresol-formaldehyde resin).     

Propylene Radical Copolymerization

Unlike ethylene, which is quite active in radical poly- and co-polymerization, the next member of the olefinic row–propylene (Pr)–is much less efficient in such reactions. Thermodynami-cally, the polymerization of Pr is permitted as is evidenced by reactions with Ziegler-Natta catalysts (The free energy change δG for the conversion of liquid Pr into amorphous poly-Pr at 25°C is -12.2 kcal/mol [1].), but the strong chain transfer activity of the Pr-monomer prevents formation of high molecular weight polymers via radical mechanism. Pr easily gives up H″ atoms with the formation of inactive and probably resonance stabilized allyl radicals CH₂[sbnd]CH[sbnd]CH₂ .(The high resonance stabilization of the Pr-radi-cal 'CH₂ CH[dbnd]CH₂, formed after separation of the H″ atom, should not be confused with a very low resonance stabilization of the Pr-radical 'CH₂ [sbnd]CH[sbnd]CH₃, formed after opening of the double bond. The Q–e scheme deals with the second type of radical and Pr is characterized by a low resonance factor, Q_pr 0.002.) As a result, Pr radical homopolymerization gives low-molecular weight polymer (even at a pressure of 15,000 atm the molecular weight of poly-Pr is only ～3000 [2, 3]).     

Copolymerization of trialkylvinyltin compounds

The polymerizations of trimethylvinyltin (TMSnV) and tributylvinyltin (TBSnV) were carried out with the use of γ-ray, radical, or ionic initiators. These monomers did not undergo the polymerization by themselves, but they did copolymerize with styrene (St) or methyl methacrylate (MMA) when a radical initiator was used. From the results obtained by the copolymerization, monomer reactivity ratios and Q–e values were obtained as follows: for the system St(M₁)? TMSnV, r₁ = 44.8, r₂ = 0.001, Q₂ = 0.005, e₂ = 0.962; for the system MMA (M₁)? TMSnV, r₁ = 25.1, r₂ = 0.03, Q₂ = 0.036, e₂ = 0.933; for the system St(M₁)? TBSnV, r₁ = 16.0, r₂ = 0.005, Q₂ = 0.017, e₂ = 0.822; for the system MMA(M₁)? TBSnV, r₁ = 27.9, r₂ = 0.03, Q₂ = 0.031, e₂ = 0.822. The abilities of TMSnV and TBSnV to polymerize are discussed on the basis of the Q and e values obtained.     

Radiation-Induced Copolymerization of Tetrafluoroethylene and Propylene. 2. Copolymerization in Solution

Copolymerization of tetrafluoroethylene and propylene in chlorofluorohydrocarbon solvents was carried out below room temperature with γ-rays from a ⁶⁰Co source. A remarkable rate-accerelating effect was observed in these solution systems, although the activation energies and the compositions of copolymers were almost the same as those in bulk system. The most effective solvent was found to be trichlorotrifluoroethane. Kinetic results of the copolymerization in trichlorotrifluoroethane solution system revealed the role of solvent to be complicated, with the possibility of affecting almost all reaction steps of the polymerization.     

Mechanism of Donor-Acceptor Alternating Copolymerization

The alternating copolymerization of butadiene and an acrylic compound in the presence of ethyl aluminum dichloride and vanadium oxychloride as complexing agents was studied kinetically for the comparison of two mechanisms, i. e., one involving an intermediate of a ternary complex of butadieneacrylic monomer-EtAIClz and the other without the complex formation. The rate of propagation was found to attain a maximum at a definite monomer composition, and this composition is not varied by changing the amount of EtAICl₂ but decreased with increasing the concentration of total monomer. This fact is explained only by the mechanism of the ternary complex intermediate. In relation to the mechanism, NMR study of the ternary complex, ESR study of the growing radical NMR study of the regularity of the copolymer, and the elementary reaction of the propagation are reviewed with discuss ion.     

Copolymerization of trioxane with phenylglycidylether

This study deals with the regularities and peculiarities of the copolymerization of trioxane (TO) and phenylglycidylether (PhGE) in nitrobenzene catalyzed by the cationic initiator BF₃Et₂O. The additions of PhGE were varied in wide bounds from 5 up to 50 mol %. No data were found about the course of copolymerization process, as well as about the influence of the polymerization conditions on the rate of exhaustion of the monomers and the composition of the copolymer. The effect of the polymerization conditions on the rate of exhaustion of comonomers was established. The kinetics of the process has been followed; the following equation is proposed: The activation energy was determined to be E_α = 15.3 kcal/mol. The course of copolymerization of TO/PhGE was compared with those of TO/DO, TO/EO, TO/St, and TO/ECH. The variation of comonomer concentrations was measured by gas chromatographic methods. The copolymers were characterized by elemental analysis, IR-, and NMR-spectroscopy, as well as by their molecular weights (M _v).     

Copolymerization of N-ethylmaleimide with stilbenes

Charge-transfer complexes in solutions of ethylmaleimide and stilbenes have been characterized by spectroscopy. The stoichiometric compositions of these complexes have been shown by Job's method to be 1:1 molar complexes. The value of the equilibrium constant K for complex formation of ethylmaleimide with stilbene derivative increases in the following probable order: ethylmaleimide–stilbene ? ethylmaleimide–dimethylaminostilbene (DMAS) < ethylmaleimide–aminodimethylaminostilbene (ADMAS). From the calculations of the electron density of the highest occupied level for the stilbenes, the charge transfer in ethylmaleimide–DMAS and ethylmaleimide–ADMAS is attributed to n → π transition, while the charge transfer in ethylmaleimide-stilbene is attributed to n → π transition. Copolymerization was carried out by γ-irradiation in benzene or THF solutions of the comonomer pairs. The alternating tendency of copolymerization was larger in the ethylmaleimide–DMAS system than in the ethylmaleimide–stilbene system. This can be explained by assuming resonance structures in the transition state of addition reaction of DMAS to the propagating ethylmaleimide unit. In the copolymerization of ethylmaleimide with ADMAS, the effect of the penultimate unit was more important than in that with DMAS.     

Plasma-Induced Living Radical Copolymerization

Plasma-induced polymerization (copolymerization) is a new method of polymer synthesis. Different comonomer pairs (methyl methacrylate-styrene, methyl methacrylate-α-methylstyrene, acrylonitrile-α-methylstyrene, methacrylonitrile-styrene, butyl methacrylate-styrene) have been copolymerized by this technique. The results showed that the process proceeds through a living radical mechanism and yields ultrahigh molecular weight macromolecular compounds (pleistomers). So, the reactivity ratio values of the monomers copolymerized by this technique are very close to those yielded by their classical radical copolymerization, and the microstructure of the copolymers is similar to that of their radically obtained homologs. Some characteristics, as well as some solution properties, of the ultrahigh molecular weight copolymers obtained are also presented.     

Copolymerization behavior of vinylimidazolium salts

Copolymerization studies of cationic monomers have been reported in the literature to yield wide variations in reactivity ratios and Q–e values, depending on the comonomer and the nature of the solvent. In this work are presented the copolymerization characteristics of a variety of vinylimidazolium salts in both water and ethanol solution. From these studies, the effect of solvent polarity, of substitution at the imidazolium 2-position, of the type of counterion, and of the hydrophilic–hydrophobic character of the monomeric salts could be ascertained. The results of the study are consistent with other related investigations, in that solvent polarity and comonomer both strongly affected copolymerization.     

Copolymerization of benzoquinone with norbornene

For the first time, the conjugated dicarbonyl compound benzoquinone has been copolymerized with the strained cyclo-olefin norbornene using catalytic amounts of the Friedel-Crafts metathesis catalytic system WOCl₄+AlCl₃. All analyses reveal that the products consist of conjugated blocks originating from benzoquinone connected with spacers originating from norbornene. The products are soluble in benzene, toluene, chlorobenzene, etc. but possess properties of the conjugated polymers. They have been synthesized via a very simple one-pot procedure.     

Copolymerization of vinylsilanes with styrene

New vinylsilanes (M₂), i. e. phenylvinylsilane (I), allylmethylsilane (II), allylphenylsilane (III), and p-vinylphenylmethylsilane (IV), were prepared and copolymerized with styrene (M₁). The monomer reactivity ratios were r₁ = 5.7 and r₂ = 0, r₁ = 36 and r₂ = 0, r₁ = 29 and r₂ = 0₁, and r₁ = 0.91 and r₂ = 1.1, respectively. From the results of infrared and NMR spectra it was indicated that the vinylsilanes participated in copolymerization in the form of a vinyl type of polymerization and not in the form of a hydrogen-transfer type of polymerization. The reaction of copolymer with alcohols and methyl methacrylate and appropriate catalysts was investigated.     

Copolymerization of chloral with trioxane

Copolymers of trichloroacetaldehyde (chloral) and 1,3,5-trioxane have been prepared in solvent-free systems with aluminium bromide as an initiator at 4 and ?15°. CH₂Cl₂ inhibited polymerization. From i.r.-spectra and chlorine determinations, the copolymers were found to have degrees of polymerization of about 40 and to contain 4–17 mole % oxymethylene units. X-ray diffraction studies indicated a completely amorphous material and no melting was observed with differential scanning calorimetry. The latter method indicated a decomposition temperature of 300°, compared with 180 and 220° for polyoxymethylene and polychloral respectively. The copolymers were stable towards chemical treatments deleterious to the corresponding homopolymers viz. 10% aq. KOH at 25° and concentrated H₂SO₄ at 130°. The stability towards alkaline solutions shows that the haloform reaction with polychloral proceeds via depolymerization and not via direct attack on the polymer chain.