Abstract: Four models are presented to describe polymerization in expanding catalyst particles. The globules are presumed to be expanding with accumulating polymer, and catalytic reaction sites are dispersed throughout the polymer matrix which is forming about them. Monomer must diffuse through the polymer to polymerize at the catalyst sites. The Thiele modulus (α), , is a ratio of characteristic diffusion time to reaction time which is a measure of the importance of diffusion relative to reaction. Polymerization rates are predicted by the models which are generally dependent on the controlling mechanism. Broad molecular weight distributions are predicted for cases of diffusion control (large α) for those models in which catalyst sites are not equally accessible to monomer. Polymerization rates decline toward an asymptotic final value as the particles expand in diffusion-controlled cases. Most of the decline which would be readily observable in a laboratory experiment would have occurred by the time the particle radii had increased to about three times their original value.

Abstract: The emulsion polymerization of vinyl acetate was carried out at 50°C using sodium lauryl sulfate as an emulsifier and potassium persulfate as an initiator, and the role of the polymer particles produced in this system was studied on the basis of a previous theory. The low value of the average number of radicals per particle obtained in this work, i.e. in the range 0.01 - 0.5, is explained by introducing a mechanism of a rapid escape of monomeric radicals produced by the chain-transfer reaction which occurs dominantly in the polymer particles. Semiempirical equations are proposed for the estimation for the average number of radicals per particle over the whole range of monomer conversion.

Abstract: Low molecular weight polymers of ethylenically unsaturated monomers are prepared by a bulk polymerization process using organic mercaptans as the polymerization catalysts and carried out in the presence of oxygen. These low molecular weight polymers find utility as high solids casting and coating resins.

Abstract: Polymerization of several epoxides and their copolymerization with tetrahydrofuran have been studied. The polymerizations were carried out by use of BF3·O(C2H5)2 as catalyst in the presence of 1,4-butanediol. Variations of catalyst and 1,4-butanediol ratio and concentration affect polymerization rate, molecular weight, and the formation of cyclic oligomers. The latter is also influenced by monomer fed ratio in the case of the copolymerizations. These effects are discussed, and some observations are made concerning the mechanism, particularly with respect to the role of the 1,4-butanediol. Mayo-Lewis monomer reactivity ratios were determined. The ratios found differed from previously published figures.

Abstract: Various kinds of the complexes of 2-phenyl-2-oxazoline with various Bronsted acids were prepared. From the elementary analysis and spectroscopic analysis of the complex, it was identified to be an equimolar oxazolinium salt. The monomer could be polymerized with the oxazolinium salt to give N-benzoyl-polyethylenimine. The polymer yield in bulk polymerization was linearly proportional to the reaction time, and the number-average degree of polymerization of the polymer obtained at the complete conversion was proportional to the initial molar ratio of the monomer to the complex. The catalytic activities of the oxazolinium salts increased with a decrease in the pKavalue of Bronsted acid in water. The results of the infrared spectroscopy and nuclear magnetic resonance spectroscopy of the oxazolinium salt at room temperature and elevated temperature indicated that the change of the double bond character of the imino and ether linkages is brought about by the complexation. On the basis of these results,...

Abstract: The equilibrium anionic polymerization of α-methylstyrene in p-dioxane, with potassium as initiator, has been investigated at 5, 15, 25, and 40°C by using high-vacuum techniques. The comparison of these results with those obtained previously for the equilibrium polymerization of α-methylstyrene in tetrahydrofuran revealed that, although the values of ΔG1c, the free-energy change upon the polymerization of 1 mole of liquid monomer to 1 bases-mole of liquid amorphous polymer of infinite chain length, are the same for both systems, there is a distinct effect of the solvent. This effect is reflected in the value of monomer equilibrium concentration and its variation with polymer concentration and is explained in terms of a solvent–monomer and solvent–polymer interaction parameter.

Abstract: The thermal bulk polymerization of cholesteryl acrylate was carried out in the solid phase, the mesomorphic phase, and the liquid phase to study the effect of monomer ordering on polymerization rate and polymer properties. The rate increased with decreasing ordering (or enhanced mobility) of the monomer. Formation of inhibitive by-products during the polymerization limited conversions to 35%. The sedimentation constant S0 = 6.2 S was the same for the polymers obtained in the three phases. The weight-average molecular weight (w) was 480,000 as determined by ultracentrifugation. Poly-(cholesteryl acrylate) formed in bulk is randomly coiled when dissolved in tetrahydrofuran. The thermal properties of the monomer are given.

Abstract: Radiation-induced free-ionic polymerization of isobutyl vinyl ether in bulk system has been studied by dilatometry and electrical conductivity measurement. Some refinements in kinetic treatment of estimate the propagation rate constant kp from the rate of polymerization and steady-state conductivity were attempted. Polymerization of superdried monomer which gave a half-power dose-rate dependence of Rp was carried out at 0, 25, and 50°C. The kp value obtained at 25°C and an activation energy for propagation were estimated as 1.2 ± 0.4 × 105 I./mole-sec and 9.6 ± 2.8 kcal/mole, respectively. In isobutyl vinyl ether, a propagation reaction in free-ionic mechanism was found to be characterized with a high frequency factor and presumably higher activation energy, compared with ion-pair mechanism. Discussions were also made as to several contrasting behaviors between the polymerization of alkyl vinyl ethers and other vinyl monomers as styrene both in free-ion and ion-pair mechanisms.

Abstract: COPOLYMER OF FROM 10 TO 70 BY WEIGHT OF AT LEAST ONE ESTER OF ACRYLIC AND/OR METHACRYLIC ACID, 25 TO 75% BY WEIGHT OF AN OPTIONALLY SUBSTITUTED STYRENE, VINYL ESTER OR (METH) ACRLONITRILE, 5 TO 50% BY WEIGHT OF AT LEAST ONE MONOMER FROM THE GROUP OF A,B-MONO-OLEFINICALLY UNSATURATED CARBOXYLIC ACID WITH 3 TO 5 CARBON ATOMS, HYDROXYALKYL ESTERS OF THE FOREGOING ACIDS AND AMIDES AND AMIDES DERIVATIVES OF ACRYLIC AND METHACRYLIC ACID WHICH IS PULVERSIBLE, HAS A SOFTENING RANGE OF FROM 75 TO 110*C. AND AN AVERAGE MOLECULAR WEIGHT OF FRROM ABOUT 500 TO 10,00 AND PROCESS OF PRODUCING THE SAME BY MIXING SAIE COMPONENTS, BULK POLYMERIZING IN A FIRST STAGE TO A CONVERSION OFF 70 TO 90% WITH AN INITIATOR DECOMPOSING INTO RADICALS BELOW 70*C. AND FINISHING BULK POLYMERIZATION IN A SECOND STAGE TO ACONVERSION OF AT LEAST 95% WITH AN INITIATOR DECOMPOSING AT FROM 120 TO 170*C.

Abstract: Bulk and emulsion polymerization have as a common featufe that there are already formed, from the start, particles which are one-phase systems consisting of polymers swollen with monomer. The composition of the particles is the same in the two cases and is constant up to about 70 per cent conversion at 50°C. Bulk and emulsion polymerization differ in that in the former case the outer phase is practically pure monomer while in the latter it consists of a dilute aqueous solution of vinyl chloride (—0.t mole/I. at 50°C). Mechanisms of bulk and emulsion polymerization are discussed. A mechanism involving desorption and reabsorption of radicals into the particles is treated in more detail. The result of the calculations seems to indicate that the bulk and emulsion polymerization are similar in that already at low conversion the main reactions, both polymerization and termination, take place in the particles. Even for bulk polymerization the number of radicals in the outer phase is, under ordinary conditions, practically independent of the rate of radical termination in that phase. The present treatment does not involve any assumption of an established thermodynamically determined equilibrium distribution of radicals in the two phases. In both these respects the present theory differs from previously advanced theories for bulk polymerization. The subdivision of the reaction zone in discrete particles has a similar effect on the bulk polymerization as on emulsion polymerization. It increases the rate of polymerization compared to that which would be obtained if the particles formed a continuous phase. The present theory may readily explain the experimentally observed drop in rate at precipitation, as well as the autocatalytic course of the reaction. The increase in the initial rate of bulk polymerization by addition of chain transfer agents results from an increase in the effective rate constant for desorption. Bulk and emulsion polymerization will respond differently to a change in the rate of desorption and absorption of radicals in the particles. This is due to the difference in the concentration of monomer in the outer phase in the two cases. In the case of bulk polymerization an increase in the rate of desorption and a decrease in the rate of absorption of radicals into the particles will tend to increase the rate of reaction whereas the opposite is expected for emulsion polymerization. New experimental evidence concerning emulsion polymerization with mixed emulsifiers consisting of sodium dodecylsulphate and different h-fatty alcohols is presented. A marked decrease in the rate is obtained by use of n-hexadecanol. The mixed emulsifier is compared with the pure anionic emulsifier at seed polymerization with a given amount of seed and number of particles. With the pure anionic emulsifier the rate of polymerization is independent of the degree

Abstract: Polyphenylene ethers of 5 microns or more in particle size which are useful for preparation of parts of electric devices are continuously produced according to oxidative polymerization of 2,6-disubstituted phenols by preparing a 15 to 35 % (by weight) solution of 2,6-disubstituted phenol in dimethylformamide or in a mixed solvent composed of toluene and methanol, subjecting the solution to polymerization in one zone while maintaining the reaction system in the state of a homogeneous solution, and transferring the polymerization liquid to another zone to complete the polymerization while allowing the resulting polymer to precipitate.

Abstract: Poly(vinylidene chloride) precipitates as a crystalline phase during the polymerization reaction. Under the conditions studied, this phase is made up of complex particles with a lamellar substructure. The detailed morphology is very sensitive to reaction medium. The morphology developed by particles formed during polymerization of vinylidene chloride in dioxane suggests a mechanism of polymerization followed by crystallization. The morphology observed in mass polymerization suggests that both processes occurs simultaneously. Kinetic data, however, suggest a solid-phase reaction mechanism for both cases. The results are analyzed by comparison with a model that takes into account the solid-phase morphology. The theoretical analysis is consistent with experimental results if it is assumed that polymerization occurs on the edges of the lamellar crystals.

Abstract: The solid-state polymerization of acrylamide, potassium acrylate, and calcium acrylate by ultraviolet radiation have been investigated. For these polycrystalline monomers both in-source and post-irradiation reactions were studied by using various sources of different intensities at constant temperatures. It is concluded that the polymerization reactions take place primarily on the surfaces of crystals. The high molecular weight material obtained at low conversions show a rapid decrease in intrinsic viscosities, probably due to degradation. Both the rate and degree of polymerization were decreased by the presence of oxygen. The various behaviors observed for these three monomers under ultraviolet radiation were regarded as another indication of the importance of crystal structures upon the solid-state polymerization reactions.

Abstract: Anionic living polymerization of α-methylstyrene containing a small amount of THF (less than 10%) was studied at temperatures between −30°C and 50°C. At any temperature studied, a certain quantity of monomer remained without further polymerization. The effect of temperature and THF content on the final state was completely different in low and high temperature regions; at temperatures lower than ca. 20°C, the final monomer concentration decreased with increasing polymerization temperature and THF content. This is explained by the concept of “stopping of polymerization due to vitrification” of the polymerizing mixture. In fact, the final reaction mixture is really glassy in most cases and the red color of living polymer buried in the glass is discolored only very slowly when exposed to air. Detailed analysis of the results showed that the vitrification stopping holds only approximately. At temperatures higher than ca. 30°C, a normal equilibrium between propagation and depropagation holds, and the final monomer concentration increased with temperature. It is, however, far less than the equilibrium monomer concentration obtained in solution polymerization at the same temperature, and it increased appreciably with the increase in THF content. It is shown that the behavior of the equilibrium for the whole concentration range can be explained satisfactorily by a thermodynamic theory of ternary mixture.

Abstract: Thermal polymerization of diphenyldiacetylene in the absence of a catalyst is a second-order reaction. The rate of polymerization is proportional to the square of monomer concentration, and the resultant molecular weight of the polymer is independent of the monomer concentration. The results suggest a mechanism in which bimolecular initiation and bimolecular termination steps are involved. The IR, NMR, UV, EPR, and mass spectral properties of the polymer are described.

Abstract: IN A PROCESS FOR BULK POLYMERIZING LIQUID DIENE MONOMER TO HIGH MOLECULAR WEIGHT RUBBERY POLYMERS IN A SYSTEM EMPLOYING CONTROLLED EVAPORATION OF MONOMER FOR REGULATING POLYMERIZATION TEMPERATURE, EXCESSIVE FOAMING WITH CONSEQUENT LOSS OF CONTROL OF THE POLYMERIZATION IS AVOIDED BY MAINTAINING THE POLYMERIZATION TEMPERATURE AT A RELATIVELY LOW LEVEL UNTIL THE POLYMER CONCENTRATION HAS EXCEEDED THAT AT WHICH THE TEMPERATURE OF EXCESSIVE FOAMING IN THE SYSTEM IS AT A MINIMUM. THE POLYMERIZATION TEMPERATURE IS THEN INCREASED FOR COMPLETING THE POLYMERIZATION.

Abstract: The kinetics of polymerization of acrylamide and acrylic acid in aqueous solution photoinitiated by the complex, diazidotetramminecobalt(III) was systematically studied at 35°C and pH = 3. Monochromatic radiation at γ = 365, 405, and 435 mμ was employed. The kinetics of polymerization were followed by measurements of the rates of monomer disappearance (bromometrically) and complex disappearance (spectrophotometrically) and the chainlengths of the polymers formed (viscometrically). The dependences of the rate of polymerization on variables like light intensity, light absorption by the complex, wavelength, monomer concentration, and hydrogen ion concentration were studied. The rates of polymerization of acrylamide and acrylic acid were found to be propertional to the square of the monomer concentration and to the first power of light absorption fraction ke and light intensity I. A kinetic scheme is proposed in the light of experimental results involving (1) a primary photochemical act of excitation of the complex, followed by the dark reaction of electron transfer within the complex producing the azide radical; (2) initiation of polymerization by the azide radical; (3) termination of the chain process by the complex molecule.

Abstract: A kinetic study of the thermal polymerization of acrylonitrile initiated by chromic acid–reducing agent (n-butanol, ethylene glycol, cyclohexanone, and acetaldehyde) systems was made. Chromic acid alone did not initiate polymerization under deaerated or undeaerated conditions. On the basis of the experimental determination of the dependencies of various variables on the rate of polymerization Rp, the rate of chromium (VI) disappearance −RM, the degree of polymerization DP, etc., a reasonable kinetic scheme was arrived at. The mechanism with the reducing agents, n-butanol, cyclohexanone, and ethylene glycol, was found to be similar but different from that with acetaldehyde. Evidence has been presented to prove the formation of radical intermediates formed by the oxidation of the reducing agent by Cr(IV). Rate parameters for oxidation of the reducing agent and polymerization of the monomer were evaluated.

Abstract: Polymerization of tetrahydrofuran (THF) by 2-methyl-1,3-dioxolenium perchlorate clarified the living nature of the polymerization. Although the initiation reaction is slower than the propagation reaction, the bonding mechanism of the initiation was shown from NMR and IR, and the formation of one polymer chain from one catalyst molecule was substantiated. Poly-THF di-cation of Mn 173000 to 322000 was prepared in high vacuum system by using a bifunctional initiator, 2,2′-octamethylene bis-1,3-dioxolenium perchlorate. Chain scission by sodium and n-butyl alcohol proved the presence of the living di-cation. The deviation from monodisperse molecular weight distribution is explained by the rate of the initiation reaction.

Abstract: The polymerization of methyl methacrylate has been studied in toluene and tetrahydrofuran solution at −78°C using butyllithium as catalyst. The structure of the polymer produced was determined by analysis of the α-methyl groups using 100 MHz NMR. It is shown that in a noncomplexing solvent such as toluene, the number of isotactic triads increases from 70% to 93% as the monomer concentration during polymerization is reduced from 5 mole/l. to approximately zero. The value of Pss/Pis depends strongly on monomer concentration, and hence any calculations regarding penultimate effects in such systems should be made at close to zero monomer concentration. In the THF solution the penultimate effect is nearly independent of monomer concentration, and both Pii/Psi and Pss/Pis are close to unity. The results may be explained in terms of a mechanism of the polymerization process in which toluene does not complex with the active site, while monomer and THF are weak and strong complexing agents, respectively.

Abstract: A number of 1,6-anhydrides were polymerized in the melt at 115°C by use of monochloroacetic acid as catalyst. In the early stages of polymerization (up to 40–50% monomer consumed), each monomer was found to disappear by a first-order rate process. The 1,6-anhydrides investigated and their relative rates of polymerization were: 1,6-anhydro-2-O-methyl-β-D-glucopyranose, 1.0; 1,6-anhydro-3,4-di-O-methyl-β-D-glucopyranose, 1.4; 1,6-anhydro-2-O-methyl-β-D-galactopyranose, 2.3; 1,6-anhydro-3-O-methyl-β-D-glucopyranose, 2.6; 1,6-anhydro-4-O-methyl-β-D-glucopyranose, 6.3; 1,6-anhydro-4-O-(β-D-glucopyranosyl) β-D-glucopyranose, 9.0; 1,6-anhydro-β-D-galactopyranose, 17; 1,6-anhydro-β-D-glucopyranose, 37; 1,6-anhydro-β-D-mannopyranose, 91; and 1,6-anhydro-2-deoxy-β-D-arabino-hexopyranose, 240. The effect of substitution on the rate of polymerization suggests this reaction is mechanistically related to the acid hydrolysis of pyranosides. The results suggest that polymerization proceeds in two stages: (1) an initial build-up of dimer followed by (2) a slower growth to higher molecular weight material.

Abstract: A method for the polymerization of vicinal alkylene oxides using a polymerization catalyst which is the reaction product of an organotin compound (A) with an esterified product (B), the organotin compound (A) containing at least one tin-to-carbon bond in its molecule, and the esterified product (B) being a completely or partially esterified product of oxyacid of phosphorus or derivative thereof, or a combination of reactants capable of forming such ester or derivative.

Abstract: Previously reported values of 1.36-2.7 at 60°C for the chain transfer constant Cs for styrene polymerization in the presence of carbon tetrabromide have been shown to be in error due to excessive extents of conversion. Most of the carbon tetrabromide is consumed by 0.5-0.7 % polymerization and subsequent reaction probably approximates to bulk polymerization. Restriction of the extent of conversion to 0.5 % gives an estimated value of 420±60 for Cs, which is independent of temperature. The activation energy and frequency factor for the chain transfer reaction of polystyrene radicals with carbon tetrabromide is 33 ± 7 kJ mol–1 and 9.2 × 109 1.mol–1 s–1 respectively. The effect on the freeze-dried polymer of precipitation in methanol has been investigated.

Abstract: Radiation-induced solid state polymerization of 1,2-cyclohexene oxide has been investigated. By the differential thermal analysis and x-ray diffraction analysis, it was found that this compound has a phase transition point at −81°C and behaves as a plastic crystal in the temperature range from −81°C to −36°C (melting point). The in-source polymerization proceeded not only in the plastic crystalline state but also in the ordinary crystalline state at temperatures below the phase transition point. The overall rate of polymerization and the rate of chain transfer to monomer in the plastic crystalline state were larger than those in the ordinary crystalline state by a factor of about forty, but the kinetic mechanisms were identical, i.e., the termination mechanisms were unimolecular in both solid states. In contrast, the kinetic mechanisms in the plastic crystalline state and in the liquid state were different. From these observations, the effects of molecular motion and molecular arrangement on the polymerizations of 1,2-cyclohexene oxide in the three phases were discussed.

Abstract: APPARATUS FOR CONTINUOUS MASS POLYMERIZATION UNDER CONDITIONS WHICH ARE SUBSTANTIALLY ISOTHERMAL AND SUBSTANTIALLY HOMOGENEOUS WITH RESPECT TO COMPOSITION ADAPTED FOR USE WITH HIGH VISCOSITY POLYMERIZING FLUID MASSES WITH A VAPOR SPACE THEREABOVE WITH REMARKABLY HIGH RATES OF THERMAL ENERGY REMOVAL THE APPARATUS EMPLOYS A REACTOR WHEREIN THERE IS A PADDLE ASSEMBLY ADAPTED TO PRODUCE IN A HIGHLY VISCOUS FLUID A COMBINATION OF CYCLICAL VERTICAL MIXING, ROLLING ACTION AND AXIAL RECIRCULATION THE REACTOR IS EQUIPPED WITH A REFLUX CONDENSER AND CONTROL MEANS REGULATING THE AMOUNT OF POLYMER WITHDRAWN FROM THE REACTOR WHEN IN USE DURING POLYMERIZATION

Abstract: APPARATUS FOR BULK POLYMERIZATION COMPRISING FEEDING MEANS FOR CONTINUOUSLY FEEDING A MONOMER AND REACTION INITIATOR ADDITIVES IN A JACKETED REACTION VESSEL WITH MIXING AND SIMULTANEOUSLY CONVEYING MEANS THEREFORE FOR MOVING THE COMPONENTS IN A MAIN CONVEYING DIRECTION. THE APPARATUS INCLUDES MEANS WITHIN THE REACTION VESSEL FOR REPEATEDLY FEEDING A PREDETERMINED AND SELECTABLE PORTION OF THE REACTION MASS IN A DIRECTION OPPOSITE TO THE MAIN CONVEYING DIRECTION AND BACKWARDS INTO THE PRECEDING REACTION SPACES.

Abstract: A CONTINUOUS MASS POLYMERIZATION PROCESS FOR MAKING POLYALKENYL AROMATIC POLYMERS HAVING A SUBSTANTIALLY UNIFORM NUMBER AVERAGE MOLECULAR WEIGHT WITHIN THE RANGE OF FROM ABOUT 20,000 TO 100,000 AND FURTHER HAVING A DISPERSION INDEX OF FROM ABOUT 2.0 TO 3.5. SUCH POLYMERS REDUCE CYCLE TIMES IN INJECTION MOLD MACHINES. THE PROCESS INVOLVES A SPECIALIZED MIXING TECHNIQUE DURING POLYMERIZATION OF MONOMER TO POLYMER.

Abstract: Graft polymers are produced by polymerizing a first monomer charge at a relatively low temperature, heat-treating the polymer, and charging additional monomer. The first monomer charge contains at least one conjugated diene of from four to eight carbons, and the first polymerization step is performed in the presence of a hydrocarbon lithium initiator. The heat-treating step is performed on the base polymer at 70 DEG -130 DEG C. for 2 - 200 hours.