A kinetic study of the polymerization of pure meta-divinylbenzene and pure para-divinylbenzene

The kinetics of the polymerization of pure meta-divinylbenzene (DVB) and pure para-divinylbenzene at 70°C have been studied in the presence of toluene and 2-ethylhexanoic acid. The apparent rate constant ratios (k_p/k_t)^1/2 for these systems have been calculated. meta-Divinylbenzene polymerizes at a higher rate than the para-isomer in both toluene and 2-EHA, and the polymerization rates of meta-DVB and para-DVB before the gel point were both higher in the presence of 2-EHA than in toluene. The monomer conversion at the visual gel point is higher for para-DVB than for meta-DVB. The gel point has also been determined indirectly by size exclusion chromatography, and these results are consistent with the gel times observed visually. The conversion of pendant vinyl groups during the polymerization has been determined by bromination. It is found that the homopolymers of poly(para-DVB) have a substantially higher content of pendant vinyl groups than poly(meta-DVB) both during and at the end of the polymerization. The molecular weight distribution (MWD) prior to gelation has been determined by size exclusion chromatography (SEC). Weight average (M̄_w); and number average (M̄_n) molecular weight prior to gelation and of the sol fractions after gelation have also been measured by SEC. There are larger fractions of high molecular weight polymers prior to gelation, when the polymerization was run in the presence of toluene, than in 2-EHA, mainly due to the differences in solvating power of the two diluents. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3345–3359, 1999     

Preparation and functionalization of reactive monodisperse macroporous poly(chloromethylstyrene-co-styrene-co-divinylbenzene) beads by a staged templated suspension polymerization

Reactive monodisperse porous poly(chloromethylstyrene-co-styrene-co-divinylbenzene) beads have been prepared by a staged templated suspension polymerization method with different concentrations of linear polystyrene porogen and chloromethylstyrene in the polymerization mixture. The presence of a small amount of linear polystyrene in the polymerization mixture leads to a dramatic increase in both the pore size and the pore volume of the resulting beads. In contrast, addition of chloromethylstyrene leads to lower surface areas and smoother surfaces due to the reduced compatibility between the polystyrene porogen and the newly formed crosslinked chains. The modification of chloromethylstyrene beads by Gabriel synthesis to obtain aminated beads has also been studied. The final number of primary amino groups is related to the starting concentration of functional benzyl chloride moieties rather than to the porous properties. Both π-basic and π-acidic type chiral selectors, (R)-1-(1-naphthyl)-ethylamine and (R)-N-(3,5-dinitrobenzoyl)phenylglycine, respectively, have been attached to the amino functionalized beads, and the resulting chiral beads have been used in the model HPLC separations of enantiomers. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2631–2643 1997     

Friedel–crafts reactions of pendant vinyl groups in macroporous monosized poly(meta‐divinylbenzene) and poly(para‐divinylbenzene) particles

Residual vinyl groups in macroporous monosized polymer particles of poly(meta‐DVB) and poly(para‐DVB) prepared with toluene and 2‐EHA as porogens have been reacted with aluminum chloride as Friedel–Crafts catalyst with and without the presence of lauroyl chloride. In the reaction between aluminum chloride and pendant vinyl groups a post‐crosslinking by cationic polymerization takes place. A reaction occurring simultaneously is the addition of HCl to the double bonds. The progress of these reactions was studied by characterization of vinyl group conversion, pore size distribution, specific surface area, morphology, and swelling behavior. In the reaction with aluminum chloride the poly(para‐DVB) particles showed a substantially higher conversion of pendant vinyl groups than the particles made of poly(meta‐DVB) independent of porogen type. The reaction with aluminum chloride led to a reduced swelling in organic solvents and an increased rigidity of the particles prepared with toluene as porogen. This is confirmed by an increase in the total pore volume in the dry state and a change in the pore size distribution of these particles. Also in the reaction with lauroyl chloride poly(para‐DVB) particles have shown a higher conversion of pendant vinyl groups than poly(meta‐DVB) particles and the acylation was almost complete at the early stage of the reaction. The swelling in organic solvents is reduced as a result of the incorporation of acyl groups into the particles prepared with toluene as porogen. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1366–1378, 2000     

Synthesis and characterization of block copolymers from 2‐vinylnaphthalene by anionic polymerization

The anionic polymerization of 2‐vinylnaphthalene (2VN) has been studied in tetrahydrofuran (THF) at ?78 °C and in toluene at 40 °C. 2VN polymerization in THF, toluene, or toluene/THF (99:1 v/v) initiated by sec‐butyllithium (sBuLi) indicates living characteristics, affording polymers with predefined molecular weights and narrow molecular weight distributions. Block copolymers of 2VN with methyl methacrylate (MMA) and tert‐butyl acrylate (tBA) have been synthesized successfully by sequential monomer addition in THF at ?78 °C initiated by an adduct of sBuLi–LiCl. The crossover propagation from poly(2‐vinylnaphthyllithium) (P2VN) macroanions to MMA and tBA appears to be living, the molecular weight and composition can be predicted, and the molecular weight distribution of the resulting block copolymer is narrow (weight‐average molecular/number‐average molecular weight < 1.3). Block copolymers with different chain lengths for the P2VN segment can easily be prepared by variations in the monomer ratios. The block copolymerization of 2VN with hexamethylcyclotrisiloxane also results in a block copolymer of P2VN and poly(dimethylsiloxane) (PDMS) contaminated with a significant amount of homo‐PDMS. Poly(2VN‐b‐nBA) (where nBA is n‐butyl acrylate) has also been prepared by the transesterification reaction of the poly(2VN‐b‐tBA) block copolymer. Size exclusion chromatography, Fourier transform infrared, and ¹H NMR measurements indicate that the resulting polymers have the required architecture. The corresponding amphiphilic block copolymer of poly(2VN‐b‐AA) (where AA is acrylic acid) has been synthesized by acidic hydrolysis of the ester group of tert‐butyl from the poly(2VN‐b‐tBA) copolymer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4387–4397, 2002     

Relaxation behavior of aliphatic-aromatic poly(ether amide)s as revealed by dynamic mechanical and dielectric methods

The mechanical and dielectric relaxation of a set of aromatic-aliphatic polyamides containing ether linkages have been examined as a function of temperature (−140 to 190°C) and frequency (3 to 10⁶ Hz). The polymers differ in the orientation (meta and para) of the aromatic rings, in the length of the aliphatic chain, and in the number of ether linkages per repeating unit. Dynamic mechanical experiments showed three main relaxation peaks related to the glass transition temperature of the polymers (α relaxation), the subglass relaxations associated to the absorbed water molecules (β) and to the motion of the aliphatic moieties (γ). Dielectric experiments showed two subglass relaxation processes (β and γ) that correlates with the mechanical β and γ relaxations, and a conduction process (σ) above 50°C that masks the relaxation associated to the glass transition. A molecular interpretation is attempted to explain the position and intensity of the relaxation, studying the influence of the proportion of para- or meta- oriented phenylene rings, the presence of ether linkages and the length of the aliphatic chain. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys, 35: 457–468, 1997     

Effect of Substituent Orientation on Selectivity between Polymerization and Cyclization: Polycondensation of (Alkylamino)benzoic Acid Dimer Phenyl Esters

Summary: The polymerization characteristics of (octylamino)benzoic acid dimer phenyl esters with para‐meta ( 2 ), meta‐para ( 3 ), and meta‐meta ( 4 ) orientation of the amino and carbonyl groups were investigated. While treatment of 2 or 3 with a base gave the cyclic dimer 6 as the main product, condensation of 4 with an initiator in the presence of a base afforded polymers with narrow molecular weight distributions.

The condensation of 4 with an initiator in the presence of a base afforded polymers with narrow molecular weight distribution.     

Effect of reaction parameters on the particle size in the dispersion polymerization of 2-hydroxyethyl methacrylate

Poly(2-hydroxyethyl methacrylate) particles in the micron size range were obtained by the dispersion polymerization. Cellulose acetate butyrate and dibenzoyl peroxide were used as steric stabilizer and initiator, respectively. The ultimate particle size could be adjusted by the selection of a suitable polymerization medium consisting of an alcohol added to toluene and by varying their relative amounts. The particle size increased with increasing solubility parameter of the mixture, i.e., by decreasing the toluene/2-methylpropan-1-ol, toluene/butan-2-ol, and toluene/3-methylbutan-1-ol ratio. The particle size decreased with increasing concentration of the stabilizer and/or initiator. At the same time, the particle size distribution became narrower. Particles prepared from polymerization mixtures purged with nitrogen before the start of polymerization were smaller, and of narrower distribution, than those prepared from nitrogen-non-purged mixtures. Equilibrium swelling of particles in toluene decreased with the decreasing content of toluene in the polymerization mixture. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3785–3792, 1999     

Reversal of order of chemical shifts. Differential solvent effects in the hydrogen shifts of toluene,m-xylene and o-xylene as determined by 320 MHz tritium NMR spectroscopy

Chemical shifts for the aromatic tritons of toluene decrease in the order meta>para>ortho for pure toluene, but in the order meta>ortho>para for dilute solutions of toluene in carbon tetrachloride, chloroform, cyclohexane and dimethyl sulphoxide; m-xylene shifts are 5>4,6>2 in the pure state and 5>2>4,6 in carbon tetrachloride and dimethyl sulphoxide; o-xylene shifts are 4,5>3,6 in the pure state and reversed in carbon tetrachloride.     

Crystallization and orientation of isotactic poly(propylene) in cylindrical nanopores

The crystallization of polymers in cylindrical geometries is important as interest in polymer nanowires and nanostructures grows. Here, semicrystalline isotactic poly(propylene) (iPP) is shown to crystallize in a homogeneous, low‐dimensional fashion when confined in cylindrical pores as small as 15 nm. A strong dependence on pore diameter is demonstrated. Isothermal crystallization studies suggest a reduced Avrami exponent as pore diameter decreases and as crystallization time increases. Complementary X‐ray diffraction with tilt (texture analysis) reveals one‐dimensional ordering of iPP crystals within pores of 40 nm diameter or less in which crystals preferentially orient, perpendicular to the pore wall. These findings demonstrate that the origin of this orientation is related to the impingement of crystals against the pore wall, thus “freezing out” polymer crystallizing in nonpreferred directions. These results show that curvature‐directed crystallization is one potential means to control a polymer's crystallization rate and orientation. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1412–1419     

Facile and quick synthesis of poly(N‐methylolacrylamide)/polyhedral oligomeric silsesquioxane graft copolymer hybrids via frontal polymerization

We report on a new strategy for fabricating well‐defined POSS‐based polymeric materials with and without solvent by frontal polymerization (FP) at ambient pressure. First, we functionalize polyhedral oligomeric silsesquioxane (POSS) with isophorone diisocyanate (IPDI). With these functionalized POSS‐containing isocyanate groups, POSS can be easily incorporated into a poly(N‐methylolacrylamide) (PNMA) matrix via FP in situ. Constant velocity FP is observed without significant bulk polymerization. The morphology and thermal properties of POSS‐based hybrid polymers prepared via FP are comparatively investigated on the basis of scanning electronic microscopy (SEM) and thermogravimetric analysis (TGA). Results show that the as‐prepared POSS‐based polymeric materials exhibit a higher glass transition temperature than that of pure PNMA, ascribing to modified POSS well‐dispersed in these hybrid polymers. Also, the products with different microstructures display different thermal properties. The pure PNMA exhibits a featureless morphology, whereas a hierarchical morphology is obtained for the POSS‐based polymeric materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1136–1147, 2009     

Convenient approach to novel functional substituted and branched poly(silylenemethylenes)

Novel poly(silylenemethylenes) have been prepared by the ring-opening polymerization of 1,3-disilacyclobutanes followed by a protodesilylation reaction with triflic acid. The silicon–aryl bond cleavage could be controlled by using different leaving groups, for instance phenyl- and para-anisyl substituents. The reactions of the triflate derivatives with organomagnesium compounds, LiAlH₄, amines, or alcohols gave functional substituted poly(silylenemethylenes). Hydrosilylation reactions or reductive coupling with potassium–graphite led to organosilicon network–polymers, which may serve as suitable precursors for silicon carbide and Si/C/N-based materials. The structures of the polymers were identified by NMR spectroscopy (²⁹Si, ¹³C, ¹H). © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 725–735, 1998     

Synthesis and characterization of new copolymers of thiophene and vinylene: Poly(thienylenevinylene)s and poly(terthienylenevinylene)s with thioether side chains

Poly[3,4-bis(3-methylbutylthio)thienylenevinylene], poly[3,4-bis-(S)-(2-methylbutylthio)thienylenevinylene], poly[3′,4′-bis(3-methylbutylthio)-2,2′:5′,2″-terthienylene-5,5″-vinylene], and poly{3′,4′-bis-(S)-[2-methylbutylthio]-2,2′:5′,2″-terthienylene-5,5″-vinylene} have been synthesized. The synthesis starts from the thiophene monomers and trimers, which are formylated to give the corresponding dialdehydes. The dialdehydes are reductively polymerized using a McMurry coupling. The polymers are characterized by GPC, optical spectroscopy (FT-IR, UV-vis, circular dichroism spectroscopy and photoluminescence) and by proton and carbon NMR spectroscopy. The polymers are soluble in common organic solvents, such as THF, chloroform, toluene, benzene and 1,2-dichlorobenzene. The solvatochromism and thermochromism of the polymers in solution are investigated, while the optical activity of the polymers is used to investigate the supramolecular aggregation. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4629–4639, 1999     

Synthesis and characterization of poly(ether naphthalimide)s

A series of new poly(ether imide)s containing the naphthalimide moiety were prepared from bis(4-fluorobenzoyl)naphthalimides and several bisphenols by aromatic nucleophilic displacement polymerization. These polyimides had inherent viscosities in the range of 0.31–1.04 dL/g in chloroform and glass transition temperatures of 283.0–341.6°C by differential scanning calorimetry. The onset temperature for 5% weight loss for all the polymers was over 448°C, as assessed by thermogravimetry at a heating rate 10°C/min in nitrogen. In addition, these novel polyimides exhibited good solubility in organic solvents including N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, 1,1,2,2-tetrachloroethane and chloroform. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3227–3231, 1999     

Preparation of 3‐arm star polymers (A3) via Diels–Alder click reaction

Diels–Alder click reaction was successfully applied for the preparation of 3‐arm star polymers (A₃) using furan protected maleimide end‐functionalized polymers and trianthracene functional linking agent (2) at reflux temperature of toluene for 48 h. Well‐defined furan protected maleimide end‐functionalized polymers, poly (ethylene glycol), poly(methyl methacrylate), and poly(tert‐butyl acrylate) were obtained by esterification or atom transfer radical polymerization. Obtained star polymers were characterized via NMR and GPC (refractive index and triple detector detection). Splitting of GPC traces of the resulting polymer mixture notably displayed that Diels–Alder click reaction was a versatile and a reliable route for the preparation of A₃ star polymer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 302–313, 2008     

Preparation of linear and hyperbranched fluorinated poly(aryl ether‐thioether) through para‐fluoro‐thiol click reaction

The para‐fluoro‐thiol “click” reaction (PFTCR) was utilized to prepare linear and hyperbranched fluorinated poly (aryl ether‐thioether). For this purpose, 1,2‐bis(perfluorophenoxy)ethane was prepared and reacted with 1,6‐hexandithiol and trimethylolpropane tris(3‐mercaptopropionate), respectively. While hyperbranched polymers were prepared using 0.5 M concentrations of starting materials at room temperature, the linear polymer syntheses were performed at different reaction temperatures and concentrations. The resulting polymers were mainly characterized by NMR measurements and a very distinct fluorine signals regarding meta‐ and ortho‐ positions in the ¹⁹F NMR were found for both polymer topologies. In addition to NMR analyses, both linear and hyperbranched polymers were further characterized by using Fourier transform infrared spectroscopy (FT‐IR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1853–1859     

Synthesis, porous structure, and underwater acoustic properties of macroporous cross-linked copolymer beads

The macroporous and elastomeric beads from polyurethane acrylate (PUA), ethyl methacrylate (EMA), and styrene (St) are prepared by suspension polymerization using n-heptane as porogen and 1,2-divinylbenzene (DVB) as cross-linking agent. The scanning electronic microscope results show that the beads of PUA–EMA–St cross-linked copolymers have many large pores on their surfaces and interiors, and the macroporous sizes are dependent of the copolymer composition and the dosages of cross-linking agents and porogen. Average porous diameters decrease as the dosages of DVB increase and the contents of PUA and porogen decrease. The cross-linked copolymers have two kinds of beads (one with many larger holes on the surface and another with much smaller pores or without pore), when the ratio of PUA to EMA and St is from 6/4 to 4/6. The macroporous and elastomeric beads can improve the underwater acoustic absorption properties of the polyurethane/epoxy (PU/EP) blend elastomer, and the underwater acoustic properties of the composites based on PU/EP blend elastomer and the beads depend mainly on the amounts of the beads and the dosages of porogen.     

Synthesis and asymmetric anionic polymerization of substituted 7‐aryl‐2,6‐dimethyl‐1,4‐benzoquinone methides

Substituted 7‐aryl‐2,6‐dimethyl‐1,4‐benzoquinone methides which have an electron‐donating methoxy substituent at the para‐position (p‐OMe, 2a ) or an electron‐withdrawing chloro one at the para‐ (p‐Cl, 2b ), meta‐ (m‐Cl, 2c ) , and ortho‐positions (o‐Cl, 2d ) of the benzene ring were synthesized, and their asymmetric anionic polymerizations using the complex of lithium 4‐isopropylphenoxide with (?)‐sparteine were carried out in toluene at 0 °C. The polymers with negative specific rotation were obtained for all of four monomers, and the polymer obtained from 2a showed smaller specific rotation value than that of polymer having no substituent (p‐H, 1 ) on the phenyl group and the polymers obtained from 2b–d showed larger ones. It was found that the kind of a substituent and its substitution position on the phenyl group affect significantly the optical activity of polymers. The largest specific rotation value of [α]₄₃₅= ?153.2° was obtained in the polymerization of 2d with an ortho‐chloro substituent. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 437–444     

Oxidative polymerization of phenylenediamines catalyzed by horseradish peroxidase

Ortho-, meta-, and para-phenylenediamines were polymerized using hydrogen peroxide as an oxidant and horseradish peroxidase as a catalyst in mixed solvents of 1,4-dioxane and water. The yield of the polymers was strongly dependent on solvent composition, and maximum yields were obtained at 15–30% 1,4-dioxane. The analysis of circular dichroic spectra of the enzyme suggested that enzyme structure was significantly modified at high 1,4-dioxane contents, which may be responsible for the decrease of catalytic activity of the enzyme. On the basis of IR and electronic spectra of the polymers, it was considered that o- and p-phenylenediamine polymers retain disubstituted benzene nuclei, which suggests that the polymerization proceeded mainly via N—N coupling. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2593–2600, 1998     

Anionic copolymerization of 2,3,4,5,6-pentafluorostyrene and divinylbenzene

Anionic copolymerizations of 2,3,4,5,6-pentafluorostyrene (PFS) with 1,3-divinylbenzene (m-DVB) and 1,4-divinylbenzene (p-DVB) were performed by using lithium diisopropylamide as an initiator in order to synthesize the fluorine-containing linear polymer with pendant vinyl groups. The products were soluble copolymers possessing both PFS and DVB monomeric units, and the DVB monomeric unit in copolymer had pendant vinyl group. This copolymerization reaction took a much longer time than that of styrene with DVB. The copolymerization parameter of this system was examined from copolymer composition curves. In this system, m-DVB was found to be more reactive than p-DVB. The reactivity of copolymerization was largely influenced by the reactivity of active species. © 1993 John Wiley & Sons, Inc.     

Ring-opening polymerization of 1,5-dioxepan-2-one initiated by a cyclic tin–alkoxide initiator in different solvents

Ring-opening polymerization of 1,5-dioxepan-2-one initiated by 1,1,6,6-tetra-n-butyl-1,6-distanna-2,5,7,10-tetraoxacyclodecane was carried out in chloroform, dichloromethane, or 1,2-dichloroethane. Effects of reaction temperature, solvent, and monomer-to-initiator ratio were investigated. Polymerization kinetics showed a first-order dependence on the monomer for polymerization in chloroform and dichloromethane at 40°C. The kinetic order with respect to the initiator were a first order when dichloromethane was used as the solvent, the order in initiator changed, depending on the initiator concentration when chloroform was used. A maximum in molecular weight was observed at 40°C when chloroform was used as the solvent. The change of solvent did not markedly alter the polymerization rate or the molecular weight of the polymers prepared, as expected from the coordination insertion mechanism. Depolymerization of the polymers formed was observed when the reaction was allowed to continue after complete monomer conversion in chloroform as reaction medium at 40°C. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3407–3417, 1999