Initial Monomer Mixture Research Articles

Homo- and copolymers of vinylfluoride

In this paper some special features of emulsion polymerization of vinylfluoride (VF) and its copolymerization with vinyliden fluoride (VDF), threefluoroethylene (ThFE), tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) in the presence of different emulsifiers, initiated by ‘redox’-systems, have been studied. It was shown that emulsifiers by their activity in the reactions of homo- and copolymerization of VF are placed in the following sequence: anionic- > nonionic- > cation-active compounds. The highest rate of homo- and copolymerization is observed while using perfluorocarbonic acids and their salts. It was established that the chemical process proceeds through the three stages: induction period, postnuclear stationary stage and finishing stage, typical for the emulsion (co)polymerization of polar monomers being low soluble in water. In all cases the obtained copolymers were enriched in VF compared to the initial monomer mixture. High activity of VF as well as low stability of radical, obtained from the VF molecule, lead to the fact that during copolymerization with fluorolefines it is charecterized by high values of copolymerization constants (r VF ⩾ 1). Introduction of fluorolefine links leads to the increase of heat-, thermo- and chemical stabilities and simplification of polyvinylfluoride conversion. A possibility of conversion of homo- and copolymers of VF into films, fibers and coverings is shown.

Synthesis and transformations of oligophenylenechlorosilanes

Hydrosilylation of oligophenylenes containing reactive residual ethynyl groups has been carried out, using dimethylchlorosilane, methyldichlorosilane and trichlorosilane. Molecules of the resulting oligophenylenechlorosilanes contain reactive SiCl endgroups. It is shown that the amount of organochlorosilane involved in the hydrosilylation reaction increases as the organochlorosilane concentration in the initial monomer mixture is increased. Some properties of the obtained oligophenylenechlorosilanes and of the products of their hydrolytic condensation have been investigated. Increased thermal stability and a reduction in the melt flow index were observed for products of the hydrolytic condensation of oligophenylenechlorosilanes in line with increase in their functionality.

Optically active vinyl polymers, 24. Copolymers of 4‐methyl‐1‐penten‐3‐one and (S)‐4‐methyl‐1‐hexen‐3‐one

AbstractCopolymers of 4‐methyl‐1‐penten‐3‐one and (S)‐4‐methyl‐1‐hexen‐3‐one have been synthesized by radical‐ and anionic initiation and their composition has been determined by 13C NMR and 1H NMR spectroscopy. A comparison between the composition of the initial monomer mixture, F, and the composition of the monomeric units in the copolymers, f, indicates Bernoullian copolymerization statistics with both types of initiators. The intrinsic viscosity, the number‐average molecular weight, and the second virial coefficient of the osmotic pressure were measured and an unusually high increase of the intrinsic viscosity with f was noticed. The results can be interpreted by assuming a strong increase in the unperturbed chain dimensions with increasing content of optically active monomeric units in the copolymer.

Copolymerization of methacrylic acid with methyl methacrylate on a polyethylene glycol matrix

Copolymerization of methacrylic acid with [ 14C]-methyl methacrylate was carried out in the presence of polyethylene glycol (PEG) as a matrix. Composition and structure of complexes were determined using NMR techniques and radiometric measurements. It was found that the complexes consist of copolymer and PEG. Dependence of the composition of the copolymer on the composition of the initial mixture of monomers was examined. The reactivity ratios were calculated and compared with those for copolymerization without matrix. It was found that the influence of polyethylene glycol results in changing reactivity ratios of comonomers and kinetics of the process.

Molecular characteristics of triple copolymers of styrene with acrylonitrile and methylmethacrylate in dilute solutions

Viscometry and light scatter have been employed to study dilute solutions of the terpolymers of styrene with acrylonitrile and methylmethacrylate of varied composition. The constants K ν and a of the Mark-Kuhn-Houwink equation have been determined in ethylbenzene, toluene, benzene, chloroform, chlorobenzene, methylethylketone, THF, 1,2-dichloroethane, 1,4-dioxane, pyridine, DMF and DMSO at 30±0·1°C. Extrapolation of the linear functions of lim log K ν=ƒ (a) a a ̊ 0·5 and Stockmayer-Fixman gave concordant (within the limits ≈2–7% values of K θ . The unperturbed dimensions of the macromolecules H 0 2./ Mw are calculated and compared with those calculated by additivity. It was found that the content in the initial monomer mixture of >44 mole% of acrylonitrile leads to the formation of terpolymers macromolecules with appreciable additional near-action.

Principles of analysis of binary copolymerization of “special” systems of the first type

An analysis was made of various models of classical and “special” systems of the first type, for which activity ratios r A and r B depend on the composition of the initial monomer mixture. Two new methods were developed for plotting integral curves of distribution according to composition for “special” systems of the first type. With the first method using composition diagrams copolymer and the degree of conversion ψ were calculated for a given sections; with the second method an analytical formula was used for ( a− ψ) in each section. It was shown that characteristics of copolymers such as position, width and form of integral curves of distribution according to composition, applicability or inapplicability of the principle of extrapolation, analysis of experimental results in coordinates of the Fineman-Ross equation enable the difference between “special” systems of the first type and classical systems to be clearly established.

On the mechanism of radical copolymerization of maleic anhydride with trans-stilbene

A study has been made of the radical copolymerization of maleic anhydride with trans-stilbene. It was found that irrespective of the make-up of the initial monomer mixture the resulting copolymers have an approximately equimolar composition. The formation of MA-stilbene charge-transfer complexes has been detected by PMR, and the equilibrium complexing constant has ben determined. On the basis of kinetic analysis a “complex” mechanism is proposed for the formation of a copolymer of constant composition with a regularly alternating structure. The contribution of charge-transfer complexes to the propofation reaction has been determined quantitatively.

Studies on the copolymerization of acrylonitrile with butyl acrylate, vinylidene dichloride, and styrene

AbstractCopolymer composition studies are reported, for different mole fractions of acrylonitrile (AN), butyl acrylate (BA), vinylidene dichloride (CV), and styrene (S) in the initial monomer mixture. A partial azeotropy of acrylonitrile was found.

Study of copolymerization of butadiene with styrene by the action of bis-triphenylmethyl barium in tetrahydrofuran

When studying polymerization in the presence of bis-triphenylmethyl barium (TPM-Ba) in THF the effect of the type of alkyl group combined with the initiator on elementary stages of chain extension was established for the first time for processes of anionic polymerization initiated by non-transition metal compounds. It was shown that the compositions of initial copolymers formed by the action of TPM-Ba are similar to those of the initial monomer mixture, whereas copolymers obtained by the action of other organic barium initiators under similar conditions have a much higher styrene content. A study of results and information concerning kinetics of separate polymerization indicate that the presence of a triphenyl methyl group in the composition of the active centre markedly reduces the rate of elementary processes taking place with monomeric styrene.

Graft copolymers from cobalt‐60 pre‐irradiated starch and mixtures of acryl‐amide with N,N,N‐trimethylaminoethyl methacrylate methyl sulfate

AbstractStarch was preirradiated with cobalt‐60 and then allowed to react with mixtures of acrylamide and N,N,N‐trimethylaminoethyl methacrylate methyl sulfate (TMAEMA·MS) in a water solution. The graft copolymers resulting were purified and characterized, and the influence of a number of irradiation and reaction variables on graft copolymer composition was determined. Although the reaction of irradiated starch with monomers must be carried out with a monomer solution purged with nitrogen to remove dissolved oxygen, a nitrogen atmosphere over the starch sample during irradiation is not necessary to achieve graft polymerization. With monomer mixtures containing 2, 5, 10, 15, and 50 mol% TMAEMA·MS, the mole percentage of TMAEMA·MS in grafted branches was less than that in the initial monomer mixture, whereas ungrafted polymer generally contained a higher percentage of the cationic monomer than was present initially. A tenfold variation in irradiation dose (0.5–5.0 Mrad) caused only small variations in percent add‐on; however, intrinsic viscosities of grafted branches decreased with increasing irradiation dose. Substituting aqueous ethylene glycol for water as the reaction medium produced more frequent grafts of lower molecular weight. Graft polymerization onto partially degraded starches gave graft copolymers with better water solubility.

Graft copolymers of starch with mixtures of acrylamide and the nitric acid salt of dimethylaminoethyl methacrylate

AbstractMixtures of acrylamide and the nitric acid salt of dimethylaminoethyl methacrylate (DMAEMA·HNO3) have been graft polymerized onto unmodified wheat starch with ferrous ammonium sulfate–hydrogen peroxide initiation. Graft polymerizations were carried out with both unswollen starch granules and granules that had been swollen by heating in water to 60°C. Ungrafted synthetic polymers were removed from graft copolymers by cold‐water extraction and were characterized by their M̄n and DMAEMA·HNO3 content. Graft copolymers were characterized with respect to per cent add‐on, M̄n and DMAEMA·HNO3 content of grafted polymer, and grafting frequency. Ungrafted synthetic polymers contained a mole percentage of DMAEMA·HNO3 equal to or greater than that present in the initial monomer mixtures; whereas in most grafted polymers the mole‐% DMAEMA·HNO3 in the grafted branches was less than that in the starting monomers. At all monomer ratios examined, polymer grafted to swollen starch granules contained a higher percentage of DMAEMA·HNO3 then polymer grafted to unswollen starch. The influence of starch granule swelling on the molecular weight and frequency of grafted branches was correlated with the composition of the initial monomer mixture. It was determined that the effect of granule swelling on graft copolymer structure would be minimal when 25–30 mole‐% DMAEMA·HNO3 was used. In an acetonitrile–water solvent system, reactions with 20 and 50 mole‐% DMAEMA·HNO3 produced graft copolymers with less DMAEMA·HNO3 in grafted branches than corresponding graft polymerizations run in water. The flocculation of 3% aqueous suspensions of diatomaceous silica was examined with selected starch graft copolymers.

The kinetics of the polymerization of aryldichlorophosphine with butadiene

Earlier we described some of the mechanisms of aryldichlorophosphine (ADP) copolymerization [1–3], in particular of phenyldichlorophosphine (PDP), toluyldichlorophosphine (TDP), and chlorophenyldichlorophosphine (CPDP) with butadiene (B) at low % conversions (up to 10%); we found that the resulting copolymer composition was independent of the monomer mixture composition. The copolymerization constants r 1 and r 2, calculated in accordance with the Mayo and Lewis equation [4], were much smaller than unity and approached zero. Subsequent interest concentrated on the study of the ADP-B copolymerization rate at larger % conversions as a function of different factors. No reference could be found to this rate of copolymerization in the literature. The purpose of the study described here was to find the rate of ADP copolymerization with B as a function of initial monomer mixture composition, of the azo-bis-isobutyric acid dinitrile (AIBN) concentration, and of the presence of benzoquinone (BQ).

Copolymerization of vinyl chloride with trans-1,2-dichloroethylene

Copolymerization of vinyl chloride with trans-1,2-dichloroethylene was carried out at various temperatures, and the properties of the copolymers obtained by the emulsion copolymerization at low temperature were examined. In the case of bulk copolymerization at temperatures higher than room temperature, the rate of polymerization, the equilibrium conversion, and [η] were lowered with increasing content of trans-1,2-dichloroethylene in the initial monomer mixture, but the Tg and softening point of the copolymers containing about 15% of 1,2-dichloroethylene unit were about 10°C. higher than these of conventional PVC resin, in spite of their inability to form films. The monomer reactivity ratios at 50°C. were 5.39 (VC) and 0.072 (trans-DCE). Emulsion copolymerization was carried out at −30°C. with the use of a redox initiator system (hydrogen peroxide–ferrous sulfate–ascorbic acid), in order to increase both the [η] and the rate of polymerization. The copolymers prepared at low temperature had higher Tg and better solubility than the VC homopolymer polymerized at the same condition or conventional PVC resin. The results of the infrared absorption spectra, the solubilities, and the calculation of sequence length of VC monomer unit in the polymer chain indicated that the stereoregularity and the crystallinity of the low temperature copolymers were lower than those of the low temperature VC homopolymers. It was concluded that higher Tg and good solubility of the low temperature copolymer were brought about by the prevention of the free rotation of the polymer chain by the random distribution of 1,2-dichloroethylene units in the polymer chain.

Solid State Polymerization of Binary Component System

Abstract The γ-ray irradiation of a solid solution of 3-chloromethyl-3-ethyloxetane and 3,3-bis-(chloromethyl)oxetane has given a copolymer with the same composition as that of the initial monomer mixture, while a BF3-catalyzed copolymerization has formed a copolymer with a different composition from that of the initial monomer mixture. In the polymerization, the solid solution has behaved like each single component crystal in respect to the relation of polymer yield to the irradiation temperature and to the crystal state of the monomers. The copolymer obtained from small crystals grown by rapid cooling has been found to have a narrower distribution of composition than that obtained from large crystals. With a solid solution of 3-chloromethyl-3-ethyloxetane and 3-fluoromethyl-3-ethyloxetance, the polymerization has been studied and similar results obtained. The mixed crystal of 3-chloromethyl-3-ethyl oxetane and diketene gives a polymer blend. The curve of the polymer yield versus the irradiation temperature is a superposition of those in the each component crystal. The mixed crystal of 3-chloromethyl-3-ethyloxetane and trioxane gives only a homopolymer of oxetane, and the temperature dependence of the yield is similar to that of oxetane, even in an eutectic composition.

Polymerization of ethylene in the presence of various composite catalysts based on TiCl 3

CONCLUSIONS (1) Copolymerization constants, r 1 and r~ were determined in copolymerization of GMA with BMA, GMA with MA and BMA with MA. (2) It was found that GMA is the most reactive and MA the least active monomer in the systems investigated. (3) In the copolymcrization of GMA with BMA an azeotropic mixture, with a content of 30 moles-~ of BMA in the initial monomer mixture, is formed. (4) The activity factors, Q and e were determined for GMA and MA according to the Alfrey and Price system. (5) The composition of ternary copolymers of BMA, GMA and MA were estimated from the copolymerization constants obtained. Experimental and calculated data showed satisfactory agreement.

Determination of the monomer reactivity ratios for the copolymerization of 2-methyl-5-vinylpyridine and triethyleneglycol dimethacrylate

THE capacity for polymerization of vinyl derivatives of pyridine as a function of their structure was first studied by Bachman and Micucci [1]. Subsequently, a number of authors [2-5] determined the reactivity ratios of 2-vinylpyridine and 4-vinylpyridine in copolymerization with various monomers. The authors assumed that the order of polymerization velocities is connected with the greater activity of vinyl groups in positions 2 and 4 as compared with those in positions 3 and 5. Farberov and Tsailingol'd [6] determined the reactivity ratios for a copolymer of 2-methyl-5-vinylpyridine and buta-l,3-dienc. Ostroverkhov, Vakarchuk, and Sinyavskii [7] have eopolymerized 2-methyl-5-vinylpyridine with styrene and determined the reactivity ratios in copolymerization of the radicals of these monomers. As a result of previous investigations [8, 9], an anion-exchange resin based on a copolymer of 2-methyl-5-vinylpyridine with triethyleneglycol dimethacrylate has been synthesized which exhibited marked absorption properties with respect to phenols from aqueous solution. The object of the present work was to study the composition of the copolymer as a function of the composition of the initial mixture of monomers and to determine the relative activities of the two radicals [10, 11], which would permit an anion-exchanger with optimum absorption properties to be obtained.

Dipole moments and molecular structure of copolymers. I. Dipole moment of methyl methacrylate–styrene copolymers

AbstractThe dielectric properties of methyl methacrylate–styrene copolymers in benzene solution have been measured, and in a theoretical treatment it has been attempted to evaluate the effective dipole moment of the methyl methacrylate group in relation to the distribution of polar group sequences in the copolymer molecule. If it is assumed that the polar groups in a polar (A)–nonpolar (B) copolymer molecule can be classified into three types such that the nearest neighbors along the chain are (I) two polar groups A, (II) a polar group A and a nonpolar group B, and (III) two nonpolar groups B (the molecular polarizations of which are denoted by PAA, PAB, and PBB, respectively), then the average molecular polarization of polar group A in the copolymer molecule, Pav, can be written in the form Here fAA and fAA2 are the probabilities of an AA sequence and a double AA sequence arising in the copolymer molecule, respectively. The values of fAA and fAA2 can be calculated from the reactivity ratios of the two monomers and the composition of the initial monomer mixture. The measurements were made on six samples of different compositions. It has been shown that the experimental values of Pav agreed satisfactorily with the values calculated from the above equation, over the whole range of copolymer composition. This seems to indicate that only the nearest neighbors in the polymer chain affect the effective dipole moment of the polar group in the copolymer molecule.

Experimental study of copolymerization. II

AbstractIn order to study further the effect of structure on monomer reactivities in copolymerization the copolymer composition as a function of initial monomer mixture composition has been determined for the following monomer pairs: vinyl acetate–vinyl chloride, ethyl methacrylate–vinylidene chloride, butyl methacrylate–vinylidene chloride, vinyl acetate–tetrachloroethylene, allyl chloride–vinylidene chloride, vinyl acetate–vinylidenechloride, methyl methacrylate–vinyl chloride, pentene‐1–vinyl chloride, allyl chloride–vinyl acetate, methyl methacrylate–2,5‐di‐chlorostyrene, vinyl chloride–vinylidene chloride, and vinyl chloride–dioctyl maleate.