bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermoplastic polyurethanes containing 12‐hydroxymethylabietanol
Authors: Wells John A. , Hedrick Glen W.
Published: April 2003

Thermoplastic polyurethane elastomers incorporating the resin acid‐derived 12‐hydroxymethylabietanol (12‐HMA) were prepared, and some physical properties are reported. A polyester macroglycol was prepared from 12‐HMA, adipic acid, and ethylene glycol. This macroglycol then was combined with either poly(tetramethylene adipate) glycol (PTAd) or poly(ethylene adipate) glycol (PEAd) and 1,4‐butanediol to give a glycol blend of 300 average hydroxyl equivalent weight (OHE). The glycol mixture then was combined with diphenylmethane 4,4′‐diisocyanate (MDI) (NCO/OH = 1.0) to give urethane polymers soluble in tetrahydrofuran. Polymers were prepared with 0, 5, 10, 15, 20, and 25%, by weight, 12‐HMA with PTAd as the other macroglycol and with 0, 10, 15, and 20% 12‐HMA with PEAd as the other macroglycol. At 15% 12‐HMA, polymers were made from glycol mixtures having 275 and 350 average OHE to demonstrate the effect of changing the hard‐segment concentration. The presence of 12‐HMA is shown to have its maximum effect on tensile properties at 15–20% in the PTAd series and at 10% in the PEAd series. In general, this effect is an increase in tensile strength and modulus and a decrease in elongation when compared with a similar polymer without the 12‐HMA.
Ethylaluminum oxide catalysts from Et2AlOLi–Et2AlCl binary system in relation to species of AlEt3–water catalyst
Authors: Araki Takeo , Aoyagi Takanobu , Ueyama Norikadzu , Aoyama Tadashi , Tani Hisaya
Published: April 2003

Equimolar reaction of Et2AlOLi and Et2AlCl gave Et2AlOAlEt2. The catalyst behavior for polymerization of acetaldehyde, propylene oxide, and epichlorohydrin was compared with that of the AlEt3–H2O (1:0.5) catalyst system. The thermal disproportionation product of Et2AlOAlEt2 derived from Et2AlOLi–Et2AlCl had the structure, (EtAlO)n, and it showed catalyst behavior quite similar to that of the product obtained by the same treatment of AlEt3–H2O (1:0.5). These ethylaluminum oxides can be regarded as species predominating in AlEt3–H2O (1:0.5) and AlEt3–H2O (1:1), respectively. Stereospecific or high molecular weight polymerizations of these species were investigated.
Aqueous polymerization of acrylamide initiated by acidic potassium permanganate–ascorbic acid redox system
Authors: Shukla J. S. , Misra D. C.
Published: April 2003

The polymerization of acrylamide initiated by the acidic permanganate–ascorbic acid redox pair has been studied in aqueous media at 30 ± 0.2°C in nitrogen atmosphere. The initial rate of polymerization has been found to be proportional to nearly the first power of the catalyst KMnO4 concentration within the range 6.0 × 10−3–14.0 × 10−3 mole/l. The rate is proportional to the first power of the monomer concentration within the range 4.00 × 10−2–12.0 × 10−2 mole/l. However, the rate of polymerization is independent of ascorbic acid concentration within the range 3.0 × 10−3–6.0 × 10−3 mole/l., but the further increase of the concentration depresses the rate of polymerization as well as maximum conversion. The initial rate increases but the maximum conversion decreases as the temperature is increased within the range 20–35°C. The overall energy of activation has been found to be 9.8 kcal/mole. The optimum amount of sulfuric acid is essential to initiate the polymerization but its presence in excess produces no effect either on the rate of reaction or the maximum conversion. Water‐miscible organic solvents and salts, e.g., CH3OH, C2H5OH, (CH3)2CHOH, KCl, and Na2SO4, depress the rate. Slight amounts of MnSO4 · H2O and a complexing agent NaF increase the rate of polymerization. Cationic and anionic detergents have been found to decrease and increase the rate, respectively, while nonionic surfactants have no effect on the rate of polymerization.
Interfacial condensation polymerization of d,l‐1,2‐propylenediamine and camphoryl dichloride
Authors: Yamaguchi Hidemasa , Minoura Yuji
Published: April 2003

The interfacial condensation polymerization of optically active camphoryl dichloride and d,l‐1,2‐propylenediamine gave benzene‐soluble and benzene‐insoluble optically active polyamides. However, the recovered unreacted 1,2‐propylenediamine was not optically active, and the selective condensation polymerization of 1,2‐propylenediamine did not occur. The specific rotation of the benzene‐soluble polyamide was positive, while that of the benzene‐insoluble polyamide was negative. The results of proton magnetic resonance spectra suggested that the benzene‐insoluble polyamide contained predominantly trans‐camphoryl residues, while the benzene‐soluble polyamide had predominantly cis‐camphoryl residues. The difference in the specific rotation is believed to reflect the difference in relative reactivity between cis‐camphoryl and the trans camphoryl residues. It was found that poly(l‐methylethylene camphoramide) did not have a helical conformation in solution.
Effect of electrostatic field on the polymer chain in the quaternized reaction of polyvinylpyridine with alkyl halides
Authors: Tsuchida Eishun , Irie Shinichi
Published: April 2003

In order to discuss the electrostatic‐field effect on a polymer reaction, the quaternization of poly‐4‐vinylpyridine–benzyl chloride (system I) was compared to that of poly‐γ‐chloromethylstyrene–γ‐picoline (system II). In these two systems, the reaction initially proceeded according to the simple second‐order kinetics. However, after the degree of quaternization exceeded 20–30 mole‐%, a deviation from simple second‐order kinetics occurred. In system I negative deviation occurred, while in system II positive deviation occurred. These phenomena occurred even though the solvent or the initial concentrations of the reactants were changed. The reasons for these phenomena are given below. In system I, the quaternized pyridine nitrogens prevented the benzyl chloride from approaching the unquaternized pyridine nitrogens. However, in system II the free γ‐picoline was attracted by the quaternized chloro‐γ‐methyl site. Furthermore, the point at which the deviation occurred was determined by the degree of chloromethylation. All these results suggest that the effect of an electrostatic field must be presumed in these two systems.
Synthesis and polymerization of various vinyl‐type monomers containing the pyrrole ring
Authors: Tsuchida Eishun , Tomono Tsugikazu , Honda Kenji
Published: April 2003

Vinyl‐type monomers containing the pyrrole ring, such as 2‐vinylpyrrole (2‐VPyrr), N‐(pyrrol‐2‐yl)methylacrylamide (PMA), N‐methyl, N‐(pyrrol‐2‐yl)methylacrylamide (MPMA), 2‐allylpyrrole (2‐AP), β‐(pyrrol‐1‐yl)ethyl vinyl ether (PEVE), 2‐diallyl‐aminomethylpyrrole (DAMP), and 3‐(2‐pyrrolylmethyleneimino)propene‐1 (PIP) were synthesized by various reactions involving characteristic properties of the pyrrole ring. Radical homopolymerizations and copolymerizations of these monomers were studied. In the homopolymerization of conjugated monomers such as 2‐VPyrr and PMA, chain transfer to the pyrrole‐containing monomer was remarkable but not degradative. The copolymerization parameters, that is, the values of r1, r2, Q1, and e1 of 2‐VPyrr, were determined to be 0.066, 0.69, 5.53, and −1.36, respectively in the copolymerization of 2‐VPyrr (M1) with MMA (M2). The Q and e values of the monomers containing a heteroaromatic ring such as 2‐vinylpyrrole, 2‐vinylfuran, and 2‐vinylthiophene were evaluated by the molecular orbital theory. The e value of PMA was found to be negative (−0.64) in the copolymerization with styrene, although e for acrylamide derivatives is generally positive. This may be explained by the intermolecular hydrogen bonding between the carbonyl group and NH group of PMA. That is, attraction or polarization of π‐electrons in the vinyl group of PMA is weakened by such hydrogen bonding. From the results of copolymerization of 2‐AP with various comonomers, the comonomers could be classified into three categories: class a monomers, in which both Q and e values are largely positive, can copolymerize with 2‐AP; class b monomers, having small e values, homopolymerize and can not copolymerize with 2‐AP; class c monomers, in which both Q and e values are small. The Q and e values of the comonomer must be largely positive in order to permit copolymerization with an allyl‐type monomer.
Cationic polymerization of 6,8‐dioxabicyclo‐[3.2.1]octane and 3,6,8‐trioxabicyclo[3.2.1]octane
Authors: Hall H. K. , Steuck M. J.
Published: April 2003

6,8‐Dioxabicyclooctane (DBO) and 3,6,8‐trioxabicyclooctane (TBO) underwent ring‐opening polymerization when treated with PF5 in dichloromethane at −78°C. These conditions were outstandingly effective for the polymerization of these bicyclic monomers, as shown by systematic variation of catalyst, solvent, and temperature. Best results were 68–84% yields of poly‐DBO, ηinh 0.26–0.33 dl/g, and ∼100% yield of poly‐TBO, ηinh 0.56–0.80 dl/g. The relationship of these results to those of previous investigators of DBO discussed.
Synthesis and polymerization of vinyl esters and vinyl ethers having bulky substituents
Authors: Nozakura Shun‐Ichi , Okamoto Takehiko , Toyora Kunimitsu , Murahashi Shunsuke
Published: April 2003

In order to clarify the effect of bulky substituents on the stereoregulation of vinyl monomers, vinyl‐1‐adamantanecarboxylate and vinyl 1‐adamantyl ether were synthesized and polymerized by radical and cationic mechanisms, respectively. As open‐chain models of the adamantyl group, vinyl trialkylacetate (alkyl = ethyl, n‐propyl, and n‐butyl) and vinyl tri‐n‐propylcarbinyl ether were also synthesized and polymerized. The adamantly group in the vinyl ester favored syndiotactic propagation in a manner similar to the trimethylcarbinyl group. Higher homologs of tri‐n‐alkylcarbinyl group showed higher syndiotacticity but this effect was saturated in higher members of the series. The effect of the adamantyl group in vinyl ether was similar to that of the tert‐butyl group, leading to high isotacticity on cationic polymerizations in nonpolar solvents and to atactic polymers in polar solvents, but the tri‐n‐propylcarbinyl group was found unique in leading to what was assumed to be a heterotactic polymer. Polymers with the adamantyl group showed much higher softening points than polymers of the corresponding open‐chain groups.
Poly‐α‐ester degradation studies. I. Introduction: Design and construction of equipment
Authors: Sutton G. J. , Tighe B. J.
Published: April 2003

The various types of polyester degradation known to occur at elevated temperature are briefly summarized with particular reference to features of potential diagnostic value. Although little is known of poly‐α‐ester degradation in particular, examination of work on other linear polyesters indicates the spectrum of analytical and kinetic information that will be needed to characterize the degradation of poly‐α‐esters of various structures. On the basis of this review, an apparatus has been designed which enables kinetic information to be simultaneously obtained by thermogravimetry, gas evolution analysis, and rheological studies of the residual polymer melt. In addition a gas sampling procedure enables twin‐column gas‐liquid chromatographic analysis to be carried out on the degradation products. Samples of the chromatographically separated degradation products are collected in a microcollector cell for infrared and mass spectrometric analysis. Other refinements include in‐line filament and Curie‐point pyrolysis techniques.
Synthesis of polyamides through active diesters
Authors: Ogata N. , Sanui K. , Iijima K.
Published: April 2003

Polycondensation reactions of active diesters including several aromatic or heterocyclic nuclei with hexamethylenediamine were carried out in order to investigate the enhancement of reactivity of active diesters for nucleophilic replacement to form polyamide for synthesis of polyamides under moderate condition. These active diesters easily induce polycondensation reaction in solutions, forming polyamides at room temperature. Solvents have a considerable influence on the rate of the polycondensation. The reactivity of these active diesters toward aminolysis is strongly controlled by the structure of the alcohol formed. The reactivity enhancement of active ester group toward amine could be attributed either to the polarization of carbonyl group or to the resonance effect of the alkoxy group.
Effect of tacticity and morphology on the formation of persistent electrical polarization in polar polymer membranes
Authors: Linder Charles , Miller Irving F.
Published: April 2003

Persistent electrical polarization (heterocharged electret formation) has been studied as a function of stereotacticity, crystallinity, and molecular weight in membranes of poly(vinyl alcohol) (PVA) prepared via different synthetic routes. Membranes of PVA–sodium polystyrenesulfonate (PSSNa) and PVA–poly(vinyl acetate) (PVAc) copolymers and PVA–PVAc–PSSNa were also investigated. The degree of persistent polarization a pure PVA membrane can support, was found to vary according to isotactic > syndiotactic > heterotactic triad concentrations. Increases in crystallinity tend to decrease persistent polarization, and such changes in crystallinity are probably responsible for the above observed order, since measurements of persistent polarization on noncrystalline PVA–PSSNa membranes were found to vary according to syndiotactic > heterotactic > isotactic with regard to the PVA. Within PVA–PSSNa membranes the presence of acetate groups reverses the behavior of PSSNa from anhancer to an inhibitor of electret formation. The results all support a model in which heterocharged electret formation involves an ion displacement in the direction of the applied field and stabilization of this ion displacement by local hydrogen bonding.
Radiation‐induced polymerization of glass‐forming systems. V. Initial polymerization rate in binary glass‐forming systems
Authors: Kaetsu Isao , Okubo Hiroshi , Ito Akihiko , Hayashi Koichiro
Published: April 2003

The radiation‐induced polymerization of binary systems consisting of glass‐forming monomer and glass‐forming solvent in supercooled phase was studied. The initial polymerization rates were markedly affected by Tg (glass transition temperature) and Tv of the system (30–50°C higher than Tg), which turned to be functions of the composition. The composition and temperature dependence of initial polymerization rate in binary glass‐forming systems were much affected by homogeneity of the polymerization system and the Tg of the glass‐forming solvent. The composition and temperature dependences in the glycidyl methacrylate–triacetin system as a typical homogeneous polymerization system were studied in detail, and the polymerizations of hydroxyethyl methacrylate–triacetin and hydroxyethyl methacrylate–isoamyl acetate systems were studied for the heterogeneous polymerization systems; the former illustrates the combination of lower Tg monomer and higher Tg solvent and the latter typifies a system consisting of higher Tg monomer and lower Tg solvent. All experimental results for the composition and temperature dependence of initial polymerization rate in binary glass‐forming systems could be explained by considering the product of the effect of the physical effect relating to Tv and Tg of the system and the effect of composition in normal solution polymerization at higher temperature, which was also the product of a dilution effect and a chemical or physical acceleration effect.
Synthesis of poly‐α,α‐diphenylglycine. II. Cationic polymerization of 4,4‐diphenyl‐Δ2‐1,2,3‐triazolin‐5‐one
Authors: Ikeda K. , Smets G. , L'abbé G.
Published: April 2003

4,4‐Diphenyl‐Δ2‐1,2,3‐triazolin‐5‐one (I) was found to undergo a cationic polymerization under the influence of boron trifluoride etherate in an anhydrous solvent. The poly‐α,α‐diphenylglycine (III) thus formed contained a larger amount of oligomers than the polymer obtained by thermal decomposition as described in the preceding paper. The molecular weight distribution was further shown to depend on the monomer and catalyst concentration and on the nature of the solvent. A mechanistic rationalization is proposed, involving propagating triazolinium ion pairs (VII) which are not interrupted by chain transfer or termination in the absence of water or alcohol. In the presence of water or alcohol, no polymerization occurred, but the normal acid‐catalyzed decomposition products (IV and V) were then obtained. 1‐Methyl‐4,4‐diphenyl‐Δ2‐1,2,3‐triazolin‐5‐one (VIII) was also treated with BF3 · OEt2 in a dry solvent at room temperature and furnished 1‐methyl‐3‐phenyl‐indolin‐2‐one (XII) instead of a polyamide. This reaction constitutes a new method for the synthesis of these heterocycles.
Organometallic polymers. XXIV. Radical‐initiated copolymerization of ferrocenylmethyl acrylate and methacrylate with acrylonitrile, maleic anhydride, and N‐vinyl‐2‐pyrrolidone
Authors: Ayers O. E. , McManus S. P. , Pittman C. U.
Published: April 2003

Ferrocenylmethyl acrylate (I) and ferrocenylmethyl methacrylate (II) have been readily copolymerized with maleic anhydride in benzene–ethyl acetate solutions. Similarly, II has been copolymerized with both acrylonitrile and N‐vinyl‐2‐pyrrolidone in benzene solutions to give higher molecular weight copolymers in high yields. In all cases azobisisobutyronitrile has been the initiator. Based on e values obtained, the metal carbonyl substituent acts as an electron‐withdrawing group. Over a wide range of comonomers (N‐vinyl‐2‐pyrrolidone, styrene, vinyl acetate, methyl acrylate, acrylonitrile, and maleic anhydride) I and II exhibit r1 values lower than (and r2 values higher than) similar copolymerizations with methyl acrylate or methyl methacrylate. Further more, the Q values found for I (0.03–0.11) and II (0.08–0.18) are smaller than those for methyl acrylate (0.46) and methyl methacrylate (0.74). Thus, I and II are less reactive than expected, presumably due to steric effects.
Effects of structure and composition on the titration curves of some synthetic copolymers in nonaqueous media
Authors: Chatterjee S. K. , Gupta Nandita Datta
Published: April 2003

p‐Aminobenzoic acid, p‐hydroxybenzoic acid, and formaldehyde were condensed in various molar proportions in the presence of acid catalyst to obtain copolymers of various compositions. Conductometric and potentiometric titrations were carried out on seven copolymers having different feed compositions in nonaqueous solvents with acid as well as base. The titration curves indicated a large number of additional breaks inflections before the complete neutralization of COOH, OH, or NH2 groups. These observations have been interpreted in terms of degree of polymerization, composition, and structure of the copolymers.
Complexed copolymerization of vinyl compounds with alkylaluminum halides
Authors: Hirooka Masaaki , Yabuuchi Hiroshi , Kawasumi Shohachi , Nakaguchi Kohei
Published: April 2003

The monomer reactivity in the complexed copolymerization of vinyl compounds with alkylaluminum halides has been extensively surveyed. Equimolar copolymers were obtained in various combinations of monomers which are classified into two monomer groups, A and B. The group B monomers are conjugated vinyl compounds having nitrile or carbonyl groups in the conjugated position and form complexes with alkylaluminum halides. The group A monomers are donor monomers having low values, such as olefins, haloolefins, dienes, and unsaturated esters. These A monomers belong to the same group of monomers which give alternating copolymers in conventional radical copolymerization with maleic anhydride, SO2, and so on. In addition the complexed copolymerization has the same specific characteristics as the conventional alternating copolymerization, i.e., high reactivities of allyl‐resonance monomers and inner olefins and no transfer of halogen atom to the copolymers in CCl4. These features suggest little or no participation of the A monomer radical. The Q‐e scheme is also discussed in terms of the monomer reactivity. More than two monomers selected from groups A and B give multicomponent copolymers in which alternating sequential structures hold with respect to A and B. Anomalous mutual reactivities between two B monomers in the terpolymerization were observed and indicate that the nature of radical in the complexed copolymerization may be different from that expected by the Lewis‐Mayo equation. The complexed radical mechanism previously proposed is discussed in connection with the specific behavior mentioned above.
Allyl stearate copolymers and terpolymers: Thermal, mechanical, and solution properties of polymers incorporating vinyl chloride
Authors: Jordan Edmund F. , Riser George R. , Artymyshyn Bohdan , Smith Stephen , Wrigley A. N.
Published: April 2003

Poly(allyl stearate) and selected copolymers and terpolymers modified by allyl stearate were investigated in this work. The systems selected and studied over a wide range of composition, included copolymers with vinyl stearate and with vinyl chloride, and terpolymers containing vinyl chloride and allyl stearate, modified further by vinyl stearate or vinyl acetate. Copolymers of allyl stearate and vinyl stearate were studied incrementally across the range of composition. In the ester copolymers the effect of degradative chain transfer on crystallization and solution properties was studied. A relation was obtained between intrinsic viscosities and number‐average molecular weights; a shift in molecular weight distribution with increase in allyl component was demonstrated. The crystallinity contributed by the side chains was shown to be characterized by isomorphic replacement regardless of molecular weight. Mechanical properties of internally plasticized copolymers of allyl stearate and vinyl chloride, in a limited composition range, were compared with corresponding data for copolymers of vinyl stearate and vinyl chloride. While molecular weight reduction of the allylic copolymers exceeded that for the vinyl ester system, the effect, in the useful plasticization composition range, was not enough to grossly affect ultimate properties. The glass transitions of the hypothetical amorphous homopolymers of both fatty esters were estimated to be the same. Because this Tg was low (ca. −110°C), only relatively small mole fractions of allyl stearate were needed for effective plasticization. Isochronal temperature–composition diagrams also showed both systems to be essentially identical, but marked differences were found for diluent mixtures incorporating di‐2‐ethylhexyl phthalate (DOP). An empirical equation, previously derived, adequately predicted the decline in degree of polymerization with increase in allyl stearate between the limits of the respective homopolymers for all copolymers studied. Terpolymers followed the trends of the copolymers and offered no special property advantage.
Studies on the nature of multiple glass transitions in low acrylonitrile, butadiene–acrylonitrile rubbers
Authors: Ambler M. R.
Published: April 2003

A study of the occurrence of multiple glass transitions in acrylonitrile–butadiene rubbers (NBR) has been made. Copolymerization theory was used to predict the change in comonomer composition with conversion for comonomer ratios both above and below the calculated azeotropic composition of 64% butadiene/36% acrylonitrile by weight. The results of these calculations suggested that multiple glass transitions, which occur only in NBR of less than 36% acrylonitrile, were due to an incompatibility of copolymer species of divergent comonomer compositions. This was shown by differential thermal analysis to be the case for various experimental polymers of known comonomer composition. A series of NBR's was prepared by incremental addition of acrylonitrile monomer during polymerization, and the resultant glass transition temperatures were evaluated. Results obtained showed that experimental samples which had single glass transitions also had a much narrower spread of comonomer species than the corresponding rubber polymerized with the use of full initial charge of both monomers. The data indicate that NBR's having a single glass transition, regardless of acrylonitrile content, may be prepared by incremental addition of acrylonitrile monomer during polymerization. Existing copolymerization theory appears to be adequate for predicting incremental monomer addition schedules suitable for the polymerization of NBR's having a single glass transition.
Friedel‐Crafts crosslinking of polystyrene
Authors: Grassie N. , Gilks J.
Published: April 2003

Polystyrene may be crosslinked by p‐dichloromethylbenzene (DCMB) in 1,2‐dichloroethane solution with SnCl4 as catalyst. Combined intra‐ and intermolecular crosslinking can be measured by evolution of hydrogen chloride and by an ultraviolet spectral method, and the results for the two methods are in excellent agreement. Intermolecular crosslinking may be calculated separately from number‐average molecular weight measurements, so that the extent of intramolecular crosslinking may be deduced by difference. Rate equations for the overall, intermolecular, and intramolecular reactions have been obtained as follows:

The anomalous behavior with respect to polystyrene concentration may be due to inhibition of the intramolecular reaction because of increasing interpenetration of polystyrene molecules as the concentration of polystyrene is increased. The rate constant for the intermolecular reaction, which shows “normal” kinetic behavior has been compared with values for the reaction of DCMB with the model compounds benzene, toluene, diphenylmethane, and benzyl chloride. The very much smaller value for polystyrene compared with the models has been accounted for in terms of adverse steric effects when the reaction is occurring in the polymer chain environment.
Redox polymerization of acrylonitrile‐kinetics of the reaction initiated by the redox system dimethyl sulfoxide–Mn(III)
Authors: Devi N. Ganga , Mahadevan V.
Published: April 2003

The kinetics of oxidation of dimethyl sulfoxide by tervalent manganese was investigated in sulfuric and perchloric acid media at 40–45°C. A mechanism involving prior complexation between reactants followed by a reversible electron‐transfer step was shown to be consistent with the kinetics. The radical ion thus produced initiates polymerization of acrylonitrile, the termination being effected by the oxidant. Rates of polymerization vary directly as the sulfoxide concentration and are proportional to the square of the monomer concentration and being independent of the oxidant. Oxidation as well as polymerization is retarded by Mn(II). Average degrees of polymerization lend support to the proposed mechanism. Rate parameters have been evaluated in the two media, and their significance is discussed.
Polymerization of vinyl chloride in the presence of precipitants. I
Authors: Arita Koichiro , Stannett V.
Published: April 2003

The kinetics of bulk and precipitation polymerization of vinyl chloride has been studied over wide range of reaction temperature by using γ‐ray induced initiation. The autoacceleration effect, which has been observed by many investigators in the case of chemically initiated bulk polymerization of vinyl chloride above 40°C and has been the most controversial aspect of the bulk polymerization of vinyl chloride, was found to disappear in the bulk polymerization below 0°C. In the bulk polymerization at 40°C, the autoacceleration effect was observed up to 20%, in agreement with the results of previous investigators, and a pronounced effect of the size of polymer particles on the time–conversion curve was observed. The kinetics of precipitation polymerization of vinyl chloride in the presence of some nonsolvents was successfully described by a oneparameter equation. A kinetic scheme, which clearly explains the zero‐order reaction behavior of bulk polymerization at low temperature and the kinetic behavior of precipitation polymerization described by the empirical equation, is proposed. The autoacceleration effect in the bulk polymerization at 40°C was considered to be essentially the same phenomenon as the small retardation period observed in the bulk polymerization at low temperature.
α‐Substituted diisopropylbenzene hydroperoxides for low‐temperature SBR polymerization
Authors: Bennett Bailey , Mueller W. J. , Nathan Richard A.
Published: April 2003

Four pure hydroperoxides were evaluated as initiators for the polymerization of styrene–butadiene rubber (SBR) at 5°C. These materials were the meta and para isomers of mono‐ and dihydroperoxy‐diisopropylbenzene. Results showed that the monohydroperoxides produced somewhat faster reactions than a control hydroperoxide, p‐menthane hydroperoxide. Response to mercaptan level adjustments was good, providing polymer with a Mooney viscosity in the 50 to 60 range. The reaction rate with the dihydroperoxides was slower, but again provided polymer with a satisfactory viscosity. Basic physical property measurements on polymers prepared with the pure hydroperoxides or control hydroperoxides showed only minor differences. It is anticipated that these differences can be eliminated by small adjustments in the compound recipe.
Méthodes chimiques d'analyse des polyacroléines linéaires
Authors: Thivollet Pierre , Golé Jean
Published: April 2003

Linear polyacroleins prepared by anionic polymerization give the structural repeat units of the types \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--}[{\rm CH}\left( {{\rm CHO}} \right)\hbox{--} {\rm CH}_{\rm 2} {\rm \rlap{--} ], \rlap{--} [CH}_{\rm 2} \hbox{--} {\rm CH}\left( {{\rm CHO}} \right)\rlap{--} ], $\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--} [{\rm CH}\left( {{\rm CH}\hbox {\rm CH}_2 } \right)\hbox{\rm O\rlap{--} ]} $\end{document} without any cyclization. Analysis of these polymers by several methods reveal the nature and amount of each structural species, and an estimation of their distribution along the polymeric chain.
Intrinsic viscosity of solutions of rigid particles at high shear rates
Authors: Layec Yves , Wolff Claude
Published: April 2003

The results of a numerical calculation which extends Scheraga's calculation on the non‐Newtonian behavior of the viscosity factor v of rigid ellipsoid solutions are given here and compared to experimental data obtained on different poly(γ‐benzyl L‐glutamate) samples in helical configuration, over a wide range of molecular weight, up to 980,000. Relations for the axial ratio p, the rotary diffusion constant D, and a test of the deformability of the polymer under shear, are given as functions of the shear‐rate dependence of the intrinsic viscosity. The experimental behavior under shear shows that PBLG becomes somewhat flexible in dichloroethane, but not in m‐cresol. The dimensions calculated from the viscometric results suggest discrete changes in the length per monomeric unit of the helix at different well defined molecular weights.
Thermal decomposition of 4,4′‐isopropylidene bis‐2,6‐dibromophenol (tetrabromobisphenol‐A)
Authors: Factor A.
Published: April 2003

The thermal decomposition of tetrabromobisphenol‐A (TBBPA) was found to proceed via an autocatalytic free‐radical process. The major products of the decomposition are HBr; mono‐, di‐ and tribromobisphenol‐A; phenol; mono‐, di‐, and tribromophenol; and eventually, char. It was generally found that o‐ and p‐halophenols are thermally unstable. In contrast, the m‐bromophenol, 3,5‐dibromo‐2,4,6‐trimethylphenol (dibromomesitol) was found to be quite stable. In addition, o‐ and p‐halo‐substituted phenols were found to react with LiI at 250°C to produce I2, while m‐halophenols did not. These results are explained by the formation from o‐ and p‐halo‐substituted phenols of a reactive halocyclohexadienone.
Thermally stable polymers derived from 2,3,5,6‐tetraaminopyridine
Authors: Gerber Arthur H.
Published: April 2003

The stable trihydrochloride salt of 2,3,5,6‐tetraaminopyridine (TAP) has been found to be a versatile intermediate to a variety of thermally stable polymers such as polybenzimidazoles (PBI), polyimidazopyrrolones (pyrrones), and polybenzimidazobenzophenanthroline (BB polymer). The controlled reactivity of two of the four amino sites of TAP · 3HCl towards diacid halides and dianhydrides makes possible the preparation of high molecular weight, soluble polyamide prepolymers at mild temperatures. PBI, pyrrones, and BB polymer are obtained from the linear polyamide precursors by heating at 150–375°C. Unoptimized cyclized polymers were aged isothermally in air at 600°F (316°C) and found to be superior to analogous polymers described in the literature. Weight retentions of up to 97% were observed after 500 hr in air at 600°F.
Prediction of molecular weight distributions in branched polymers
Authors: Jackson R. A. , Small P. A. , Whiteley K. S.
Published: April 2003

A theoretical treatment of long branching in radical polymerization in a continuous stirred tank reactor is presented. The treatment takes into account radical termination by disproportionation and/or combination, transfer to polymer and/or additive of low molecular weight, residence time, and injection of polymer. In the absence of added polymer, the molecular weight distribution depends upon four parameters which can be expressed as P̄n and ratios of the rate of polymerization to the rate at which radicals (a) leave the reactor, (b) combine, and (c) transfer to polymer. The kinetic equations were converted into a differential equation which was solved numerically to give polymer and radical moments. An analytical solution is presented for the case where combination is absent. P̄w/P̄n is predicted to increase smoothly in a markedly exponential manner with increasing polymer transfer, combination, P̄n, and mean residence time. At no stage do any of the moments become infinite unless the residence time is infinite. For polymers of wide distribution, the second and higher radical moments can exceed the corresponding polymer moments so that most of the large molecules leave the reactor as radicals. Beasley's and Nicolas's treatments are shown to be limiting cases at low polymer transfer.
Alternating cooligomerization of isoprene and propylene with vanadium catalyst
Authors: Furukawa Junji , Tsuruki Shigenori , Kiji Jitsuo
Published: April 2003

Alternating cooligomerization of isoprene with propylene has been investigated between −30 and 0°C, VO(acac)2–Et3Al–Et2AlCl being used as catalyst. In the presence of an excess of propylene, 2,4,7‐trimethyl‐1,4‐octadiene and 2,4‐dimethyl‐1,4‐nonadiene are selectively formed. The formation is explained by the alternating coordination of isoprene and propylene to the vanadium. When triphenylphosphine or pyridine is added to the catalyst, the cooligomerization is suppressed while the formation of the dimer and trimer of isoprene is high.
Copolymerization of styrene and diethyl fumarate with zinc bromide. V. Electroinitiated copolymerization at high current strengths
Authors: Phillips D. Colin , Smith J. D. B. , Davies David H.
Published: April 2003

The electroinitiated copolymerization of styrene and diethyl fumarate in methanol solvent with zinc bromide as electrolyte has been investigated at high current strengths (200–500 mA). Unlike the copolymerization behavior observed at lower current strengths (< 200 mA), it is found that the cathodically produced copolymers deviate from a 1:1 composition and show a significant deficiency in styrene. The copolymer products can be separated into two well‐defined fractions: a toluene‐soluble fraction (normal copolymer) and a toluene‐insoluble one (styrene‐deficient copolymer). These deviations in copolymer composition from a 1:1 monomer ratio are attributed to the occurrence of cathodically induced electroreductive hydrolysis side reactions with diethyl fumarate leading to the formation of carboxylate or acid salt species. Reaction of these hydrolyzed species with diethyl fumarate results in the formation of fumarate‐rich copolymers.
Interaction of polyvinylpyrrolidone with methyl orange and its homologs in aqueous solution: Thermodynamics of the binding equilibria and their temperature dependences
Authors: Takagishi Toru , Kuroki Nobuhiko
Published: April 2003

The interaction of polyvinylpyrrolidone with methyl orange, ethyl orange, propyl orange, and butyl orange has been studied by an equilibrium dialysis method at 5, 15, 25, and 35°C. The first binding constants and the thermodynamic parameters in the course of the binding have been calculated. It was found that the free energy and the enthalpy changes are all negative and the entropy change is largely positive. The longer the alkyl chain of the dyes, the more positive is the enthalpy change (though it is always in the negative direction) and hence the larger is the entropy change. The favorable free energy of the binding of butyl orange observed for the formation of the dye–polymer complex seems to be a result of a favorable entropy change rather than any favorable enthalpy change. Temperature dependences of the thermodynamic functions were apparently observed. That is, ΔF and ΔH become larger in absolute magnitude as the temperature increases. The positive quantity of ΔS tends to decrease with increasing temperture. All these facts obtained can be interpreted satisfactorily by the hydrophobic interaction between hydrocarbon portions of the dyes and nonpolar parts of the macromolecule.
Studies on polymers from cyclic dienes. XII. Cationic polymerization of spiro[2,4]hepta‐4,6‐diene
Authors: Ohara Osamu , Aso Chuji , Kunitake Toyoki
Published: April 2003

Polymerizations of spiro[2,4]hepta‐4,6‐diene were carried out with cationic initiators and Ziegler‐type catalysts. This monomer polymerized very rapidly with a variety of cationic initiators, and low monomer and initiator concentrations had to be employed in order to avoid formation of crosslinked polymers. The polymer contained 1,2 and 1,4 addition units, and there was no indication of the opening of the cyclopropyl ring in the monomer unit. The following relationship was obtained: [η] = 4.5 × 10−8M̄n1.71. The exponential coefficient of this equation is much greater than those typical of vinyl polymers, suggesting that the polymer chain is very stiff. The polymer showed much enhanced resistance to autoxidation as compared with polycyclopentadiene, and its softening point was above 200°C. These interesting physical and chemical properties of the monomer and the polymer can be associated with their spiro structures.
Thermal analysis of polystyrenes crosslinked by p‐di(chloromethyl)benzene
Authors: Grassie N. , Gilks J.
Published: April 2003

Series of progressively crosslinked polystyrene have been prepared by the reaction off linear polystyrene with p‐di(chloromethyl)benzene in dichloroethylene solution with stannic chloride as catalyst. By using a DTA technique it has been shown that the glass transition temperature Tg increases with crosslinking very much faster than is accounted for purely by increase in molecular weight. This type of crosslink is only about half as effective in increasing Tg as are crosslinks introduced by copolymerization of styrene with divinylbenzene. Thermal analysis by use of the thermal volatilization analysis (TVA) technique shows that stability, as measured by the evolution of volatile products, decreases as crosslinking progresses, and thermal gravimetric analysis (TGA) confirms this.
Poly α‐ester degradation studies. IV. Rheological studies of polymer degradation
Authors: Lovett A. J. , O'Donnell W. G. , Sutton G. J. , Tighe B. J.
Published: April 2003

The Farol‐Weissenberg rheogoniometer has been used to follow molecular weight changes during the degradation of certain poly‐α‐esters in the melt state. By observing the change in melt viscosity at low shear rates it had been shown that the decomposition of the poly(isopropylidene carboxylate) is substantially first‐order with respect to the molecular weight of the residual polymer. The derived kinetic parameters are in good agreement with those previously obtained by other techniques. This provides a substantial piece of supporting evidence for the view that degradation takes place predominantly by intramolecular ester interchange involving the formation of 1,1,4,4,‐tetramethylglycollide. The introduction of β‐chlorine atoms into the polymer structure leads to a more complex degradation pattern. Thus the presence of a single β chlorine atom per repeat unit, as in poly(3‐chloro‐2‐methyl‐2‐hydroxypropionic acid) leads to a substantially similar dependence on molecular weight with the added complication of progressive crosslinking which becomes more apparent in later stages of the reaction. This crosslinking reaction plays an increasingly important part as the extent of chlorination of the polymer is increased. In addition, the presence of chlorine leads to an increased sensitivity of the degradation reaction to the presence of oxygen.
Carbon‐13 nuclear magnetic resonance of ethylene–propylene copolymer and the determination of sequence distribution of monomeric units
Authors: Tanaka Yasuyuki , Hatada Koichi
Published: April 2003

The 13C‐NMR spectra of ethylene–propylene copolymers and their model compounds were measured at 15.1 MHz. Assignments of the signals were carried out by using the equation of Grant and Paul and also by comparing the spectra with those of squalane, hydrogenated natural rubber, polyethylene, and atactic polypropylene. The accuracy and the precision of intensity measurements, that is, the deviation from the theoretical values and the scatter of the measurements, respectively, were checked for the spectra of squalane and hydrogenated natural rubber and were shown to be at most 12% for each of the signals. On the basis of these results the mole fractions of the four types of the dyad sequences, that is, the propylene–propylene (head‐to‐tail and head‐to‐head), the ethylene–propylene, and the ethylene–ethylene sequences, were determined together with the average sequence lengths of both monomer units.
Electron spin resonance study of ethylene–acrolein copolymer irradiated with ultraviolet light
Authors: Tsuji Kozo
Published: April 2003

When ethylene–acrolein copolymer was irradiated at −196°C with ultraviolet light, a sharp singlet spectrum with a g value of about 2.001 was predominant. This spectrum is attributed to acyl radicals, which are produced by dissociation of a hydrogen atom from an aldehyde group. At the same time it is supposed that dissociation of formyl groups also took place to give alkyl radicals, CO, and H2. The alkyl radicals reacted with CO molecules to give acyl radicals at −78°C under vacuum. Peroxy radicals were produced when the sample irradiated at −196°C in the presence of air was treated at −78°C. The sample irradiated at −196°C was warmed to near 0°C and an apparent singlet spectrum with a g value of about 2.004 was observed. This spectrum was tentatively assigned as due to free radicals of the type
Vinyl acetate emulsion polymerization. I. Effect of ionic strength and temperature on monomer solubility in the ionically stabilized polymer particle
Authors: Klein A. , Kuist C. H. , Stannett V. T.
Published: April 2003

Solubility of monomer in the polymer was strongly affected by ionic strength; with increasing ionic strength, solubility was found to increase. At constant temperature, this was entirely due to the decrease in interfacial tension, as the condensation of surfactant proceeded at the interface. The temperature affected both the polymer–solvent interaction parameter as well as the interfacial tension. These are the two parameters on which solubility depends. The variations of interfacial tension with temperature was found to be complex, but entirely dependent on the entropic consideration of adsorption. The polymer–solvent interaction parameter–inverse temperature dependence was found to be linear, as expected.
Inorganic glasses as crosslinked polymers: The relationship between crosslink density and transformation temperature in phosphate glasses
Authors: Ray N. H.
Published: April 2003

Most substances that form stable glasses are polymers, and inorganic oxide glasses are no exception. Because most oxide glasses are highly crosslinked polymers it is not possible to measure properties in solution, and parameters such as molecular weight and molecular weight distribution which are used to characterize organic polymers are meaningless in the context of oxide glasses. Instead, the network connectivity or a measure of crosslink density must be used to characterize their structure. In silicate glasses, the network connectivity can be changed significantly only by altering the composition, but phosphate glasses of fixed composition can be prepared with variable hydroxyl contents and consequently different crosslink densities. In this paper it is shown that the relationship between the transformation temperature T(x) and crosslink density x of phosphate glasses is similar to that observed for organic polymers and can be described by an equation of the form

where T(0) is the transformation temperature of the corresponding linear polymer and K is a constant which is approximately the same for three different phosphate glasses that have been studied.
Organometallic condensation polymerization: Carbon–carbon bond formation by coupling of 1‐phenylcyclohexenyl chromophores
Authors: Relles Howard M.
Published: April 2003

Diolefins XV and XVII have been successfully polymerized with metallic lithium in tetrahydrofuran by a radical‐anion, carbon–carbon coupling reaction. The coupling takes place in the mode known for the dimerization of α‐methylstyrene and 1,1‐diphenylethylene and shown herein for 1‐phenylcyclohexene.
Chemical structure of poly(ethylene terephthalate)–styrene and nylon–styrene graft copolymers prepared by radiation techniques
Authors: Sakurada I. , Ikada Y. , Kawahara T.
Published: April 2003

The graft copolymerizations of styrene onto poly(ethylene terephthalate) (PET) and nylon fibers were carried out by the mutual irradiation and preirradiation methods. True graft copolymers were isolated from the products by extraction and characterized by hydrolysis and osmometry. Among the swelling agents employed, methanol was most effective for increasing the extent of grafting onto PET. In both methods of the grafting, the molecular weight of polystyrene formed in the substrate matrix was higher than one million if no chain‐transfer agent was added to the monomer solution. Similar to the case of radiation grafting onto poly(vinyl alcohol) and cellulose, the isolated graft copolymer carried only one branch per copolymer molecule in both cases. Of great interest is the particularly low extent of grafting in the case of PET–styrene. This should be attributed to the low sensitivity of PET to radiation. The grafting site on the mother polymer molecule is discussed on the basis of the solution behavior of the branch polymers separated from the backbone.
Studies of the polymerization of diallyl compounds. XIX. Further discussion of the cyclocopolymerizations of diallyl phthalate with monovinyl monomers by the use of the model compounds
Authors: Matsumoto Akira , Aso Takayuki , Tanaka Seiji , Oiwa Masayoshi
Published: April 2003

In the cyclocopolymerizations of diallyl phthalate (DAP) with monovinyl monomers the reactivity ratio of the cyclized radical, rc, was smaller than that of the uncyclized radical, r1; this was ascribed to steric hindrance in the addition reaction of the cyclized radical with DAP. In this paper, the validity of the values of rc and r1 is discussed on the basis of model experiments, i.e., the copolymerization of DAP in dilute solution corresponding to rc and that of allyl propyl phthalate, to r1. The copolymerizations of methyl allyl phthalate and allyl octyl phthalate with vinyl acetate are also presented.