bluuebunny/crossref_metadata_2025 huggingface dataset:
Crosslinkable aromatic polyketones with maleimide pendent groups
Authors: Mikroyannidis John A.
Published: April 2003

A novel class of crosslinkable aromatic polyketones with maleimide pendent groups were synthesized by Friedel–Crafts polymerization from 5‐maleimido‐isophthaloylchloride and various aromatic reagents. The synthesized polyketones showed a poor solubility. They were characterized by inherent viscosity measurements and infrared (IR) spectroscopy. Differential thermal analysis (DTA) revealed that their crosslinking occurred at relatiively lower temperatures (167–253°C) than did thermal polymerization of ordinary bismaleimides. The thermal‐and thermooxidative stability of crosslinked resins were evaluated by dynamic thermogravimetric analysis (TGA) as well as by isothermal gravimetric analysis (IGA). They were stable in N2 up to 303–329°C and formed anaerobic char yield 50–62% at 800–C. The thermal stability of crosslinkable polyketones was significantly increased after curing.
Thermostable laminating resins based on aromatic diketone bis‐ and tetramaleimides
Authors: Mikroyannidis John A.
Published: April 2003

Twelve structurally different bis‐ and tetramaleimides were synthesized by Friedel–Crafts reaction between 4‐maleimido‐benzoylchloride or 3,5‐bismaleimido‐benzoylchloride and various aromatic reagents. They were characterized by infrared (IR) and proton nuclear magnetic resonance (1H‐NMR) spectroscopy. Crosslinked resins were obtained by curing the monomers at 250°C/6 h. Thermal characterization of monomers and cured resins was accomplished by differential thermal analysis (DTA), dynamic thermogravimetric analysis (TGA), and isothermal gravimetric analysis (IGA). Tetramaleimides were polymerized at lower temperatures than did the respective bismaleimides. The cured resins were stable up to 317–385°C in N2 atmosphere and formed an anaerobic char yield of 52–66% at 800°C.
Synthesis and mesogenic properties of four series of polyesters derived from dicarboxylic and dihydroxylic aromatic monomers
Authors: Barberá Joaquín , Navarro Fernando , Oriol Luis , Piñol Milagros , Serrano José Luis
Published: April 2003

Some members of four series of polyesters were synthesized by the direct polycondensation of two types of dicarboxylic acids (4,4′‐dicarboxy‐α,ω‐diphenoxyalkanes and 4,4′‐dicarboxy‐α,ω‐dibenzoyloxyalkanes) with two types of bisphenols (4,4′‐dihydroxy‐α,ω‐diphenoxyalkanes and 4,4′‐dihydroxy‐α,ω‐dibenzoyloxyalkanes) using tosyl chloride in pyridine in the presence of N, N‐dimethylformamide. The 1H‐NMR spectra of the polymers synthesized showed that these polymers have an ordenated structure. The mesogenic properties of these polymers were studied by optical microscopy and differential scanning calorimetry. Many of the polymers show nematic mesomorphism.
Liposome formation of selectively‐polymerized diene‐containing phospholipids and their postpolymerization
Authors: Takeoka Shinji , Ohno Hiroyuki , Iwai Hidetaka , Tsuchida Eishun
Published: April 2003

Small and large unilamellar liposomes composed of 1,2‐bis(2,4‐octadecadienoyl)‐sn‐glycero‐3‐phosphorylcholine (DODPC) are prepared by sonication and extrusion, respectively. They are polymerized with water‐insoluble radical initiator, azobis(isobutyronitrile) (AIBN) which can selectively polymerize diene groups in 1‐acyl chains of the lipids. Polymerized liposomes are freeze‐dried to obtain the polymerized liposome powder. There are two methods to redisperse lyophilized liposomes into water. The extrusion is an effective method to disperse them because the energy at extrusion is necessary only for redispersion, whereas the excess energy at sonication gives damage on liposome structure. There is no difference in stability between polymerized liposomes before and after redispersion with extrusion. DODPC polymers, obtained from free radical‐initiated polymerization with AIBN, are linear and have polymerizable diene groups in 2‐acyl chains. The liposome powder is therefore soluble in organic solvents. Reconstruction of polymerized liposomes is performed with lipid polymers having low or high molecular weight. The lipid polymers having high molecular weight provide stable large unilamellar liposomes by ethanol injection, but unstable small unilamellar liposomes are formed by sonication. The liposomes reconstructed from lipid polymers having low molecular weight are unstable regardless of their size. After reconstruction of liposomes selectively polymerized by AIBN, diene groups in 2‐acyl chains are polymerized by water‐soluble radical initiator or UV‐irradiation to yield highly crosslinked structure. Their stability is improved remarkably by this postpolymerization.
The effect of masked isocyanates on the moisture absorption of MY 720/DDS epoxy resin
Authors: Lonikar S. V. , Rungsimuntakul N. , Gilbert R. D. , Fornes R. E.
Published: April 2003

Several masked isocyanates were prepared with variations in both the type of isocyanate and masking group. They were characterized by elemental analysis and NMR spectroscopy, and their unblocking temperatures were determined. In general, higher unblocking temperatures were obtained using acyclic and cyclic aliphatic isocyanates and fluorinated phenols. Those with unblocking temperatures in the range of 120–180°C were incorporated into MY 720/DDS epoxy resin prior to cure. Highly fluorinated variations were incompatible with the resin. IR and DSC analyses showed that residual functional groups in the epoxy resin reacted with the masked isocyanates. Reductions in moisture absorption as high as 65% were obtained depending on the masked isocyanate. DMA studies showed that the Tg of the epoxy resin is lowered by incorporation of the masked isocyanate but the elastic modulus (E′) is relatively unchanged at temperatures below Tg.
Miniemulsion copolymerization of vinyl acetate and butyl acrylate. IV. Kinetics of the copolymerization
Authors: Delgado Joaquin , El‐Aasser Mohamed S. , Silebi Cesar A. , Vanderhoff J. W.
Published: April 2003

The copolymerization kinetics of conventional emulsions and miniemulsions of 50:50 and 25:75 molar ratios vinyl acetate–butyl acrylate monomer mixtures were studied using sodium hexadecyl sulfate as surfactant. Hexadecane was the cosurfactant used in the preparation of the miniemulsions, and ammonium persulfate was the initiator used in the polymerizations. The rate of polymerization showed four regions which extended to different conversions depending on the type of emulsion used (conventional or miniemulsion). The rate of polymerization for the miniemulsion process was always slower than for the conventional process. The dependence of the rate on the initiator concentration was higher for the miniemulsion process. The number of particles nucleated in the miniemulsion copolymerization process was lower than in the conventional emulsion copolymerization process. The initiator and surfactant concentration dependence of the number of particles were 0.8 and 0.25 for the miniemulsion copolymerization process and 0.0 and 0.68 for the conventional emulsion copolymerization process respectively. These effects were attributed to the different particle nucleation mechanism operating in each process.
A study of the relative reactivity of maleic anhydride and some maleimides in free radical copolymerization and terpolymerization
Authors: Florjańczyk * Zbigniew , Krawiec Włodzimierz , Such Katarzyna
Published: April 2003

Composition data for the free radical copolymerization of maleic anhydride with N‐phenylmaleimide in toluene at 60°C have been obtained. Relative reactivity ratios in terminal and penultimate models using nonlinear least‐squares optimization routine have been determined. The standard error was found to be somewhat smaller in the penultimate model, but is still larger than the uncertainty estimated for the copolymer composition. Terpolymers of maleic anhydride and styrene with maleimide, N‐butylmaleimide, N‐phenylmaleimide, and N‐carbamylmaleimide were obtained. On the basis of analysis of the product composition at various monomer feeds the relative reactivity of maleic anhydride and maleimides in these reactions is compared and the influence of the structure of thesemonomers on the rate of some chain growth reactions is discussed.
Modification of polymer surfaces by two‐step plasma sensitized reactions
Authors: Foerch R. , Mcintyre N. S. , Hunter D. H.
Published: April 2003

New reaction products have been generated on polyethylene and polystyrene surfaces using a novel two‐step process. The first stage involves exposure to a downstream nitrogen plasma, and the second to either ozone or a corona discharge. It is observed that each of the two‐step reactions yields very different reaction products, with an apparent increase in the formation of CO functional groups in the former case and the formation of surface  NO2 groups in the latter case.
Polyimidines. XI. Polyimidines from 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride and 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride
Authors: Mores Maryanne , Cassidy Patrick E.
Published: April 2003

Two new bis(benzylidenephthalide)monomers were synthesized by melt condensation of phenylacetic acid with 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) and with 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA). A mixture of three isomers for each monomer was obtained and polymerized with diamines to produce new polyimidines. Polymerizations were conducted with m‐xylylenediamine (MXDA) or 4,4′‐oxydianiline (ODA) in quantitative yields for the undehydrated intermediate. Inherent viscosities ranged from 0.17 to 0.35 dL/g in N,N‐dimethylformamide (DMF) or N‐methyl‐2‐pyrrolidone (NMP). These intermediate poly(hydroxylactams) were thermally dehydrated to polyimidines which exhibited a 10% weight loss, as high as 546°C in nitrogen. Inherent viscosities of the dehydrated (cured) polyimidines ranged from 0.14 to 0.20 dL/g in NMP. Brittle films could be cast from NMP solutions.
Syntheses of flame‐retarding 4‐phosphonatomethyl‐2,6‐dibromophenyl trimellitate anhydrides and their reactivities toward epoxy resin
Authors: Yang Chin‐Ping , Lee Tzong‐Ming
Published: April 2003

4‐Phosphonatomethyl‐2,6‐dibromophenyl trimellitate anhydrides (HDBBP–TMA) were prepared by the condensation of 4‐chloroformyl phthalic anhydride with corresponding 4‐hydroxy‐3,5‐dibromobenzyl phosphonates (HDBBP). These materials could be used to produce excellent flame retardance in epoxy resins when the substances were chemically combined with the polymer. The reactive‐type HDBBP–TMA showed much better phosphorus–bromine synergistic effects on the flame retardancy of epoxy resins than the additive‐type compounds such as HDBBP or the mixture of bromo compound (such as 2,6‐dibromo‐p‐cresol) and phosphorus compound (such as triphenyl phosphite). Meanwhile, the oxygen index of cured epoxy resin was proved to be relative to the extent of crosslinking. Reactivities of HDBBP–TMA toward epoxy were also studied by rheometer in comparison with those of trimellitic anhydride and its derivatives such as 4‐methylphenyl trimellitate anhydride and 4‐methyl‐2,6‐dibromophenyl trimellitate anhydride.
Chelate resin‐iron(II) complex: Adsorption and desorption of nitrogen monoxide at the dry state
Authors: Asanuma Hiroyuki , Toshima Naoki
Published: April 2003

A chelate resin‐immobilized iron(II) complex was prepared from iron(II) and poly(styrenecodivinylbenzene) which is functionalized by iminodiacetic acid group. It is activated by drying after having been washed with methanol. The resin complex can rapidly adsorb nitrogen monoxide, and the nitrogen monoxide adsorbed on the complex can be released by the treatment with heat. The adsorption of nitrogen monoxide proceeds through the 1:1 complex formation of the NO molecule with the iron(II) atom, and its complex formation constant was calculated as 8330 atm−1 at room temperature from Langmuir plots. This value does not depend on the solvents used for washing. The activation of the resin complex by the treatment of washing with methanol is derived by increasing the amount of effective iron(II) ions due to the increase in the surface area. Moreover, this resin complex was revealed to have high complex formation constant with NO and high durability to dioxygen compared with an aqueous solution of ethylenediaminetetraacetato–iron(II) complex, which is the corresponding monomeric absorbent commonly used for nitrogen monoxide.
The formation of propylene fumarate oligomers for use in bioerodible bone cement composites
Authors: Domb Abraham J. , Laurencin Cato T. , Israeli Orli , Gerhart Tobin N. , Langer Robert
Published: April 2003

Poly(propylene fumarate) (PPF) oligomers were synthesized by step polymerization using bis(2‐hydroxypropyl fumarate) or propylene bis(hydrogen maleate) as starting materials. Oligomers possessing identical degrees of polymerization (DP), but varying in their end group character (either hydroxyl or carboxyl) were first prepared and characterized, then used as part of a bone cement preparation consisting of oligomer, tricalcium phosphate, calcium carbonate, and methyl methacrylate. Compressive strength of the resulting composite appeared to be dependent on both the degree of polymerization of the PPF, and the nature of the oligomers' end groups.
Simulation of the latex particle morphology
Authors: Cal José C. De La , Urzay Rosa , Zamora Aranzazu , Forcada Jacqueline , Asúa José M.
Published: April 2003

A model is presented for the simulation of the structuration of polymer particles under conditions in which the new polymer chains are compatible with the polymer previously formed. The model involves the calculation of the monomer concentration gradients within the particles due to discrepancies in thermodynamic interactions between the monomer and the different polymers present in each part of the polymer particle. In addition, the distribution of free radicals in the latex particle is taken into account. This distribution results from the anchoring of the hydrophilic end‐group of the growing polymer chain on the surface of the particle. The model was applied to the simulation of the polymerization of vinyl acetate on a butyl acrylate–vinyl acetate copolymer seed. It was found that the development of the particle morphology was mainly due to the profile of concentration of radicals in the particle. On the other hand, the effect of the monomer–polymer thermodynamic interactions on the particle morphology was found to be negligible. However, it has to be pointed out that this is because, for the system studied, the interaction parameters of vinyl acetate with polyvinyl acetate and polybutyl acrylate are nearly identical.
N,N,N′,N′‐tetramethylethylene diamine as a co‐catalyst in the anionic polylymerization of methyl methacrylate
Authors: Wesslén Bengt , Mattsson Gunnar
Published: April 2003

Anionic polymerization of methyl methacrylate in toluene solution has been studied. The polymerizations were initiated by fluorenyllithium as well as by butyl‐, benzyl‐, and phenylmagnesium halides, and carried out in the presence of polar additives. Especially the organomagnesium initiators gave generally rise to highly isotactic polymers (mm = 0.90‐0.95) in the absence of solvating additives. In the presence of the bidentate ligand N,N,N′,N′‐tetramethylethylene diamine (TMEDA) at molar ratios of 1–2 relative to magnesium, highly syndiotactic polymers were obtained at −78°C (rr = 0.8–0.9), while at higher temperatures stereoblock polymers or stereocomplexes were formed. It is proposed that at low temperatures the magnesium cations are strongly solvated under the influence of TMEDA, with the formation of monomeric ion pairs. The large solvated magnesium cations will not have any directional influence on the monomer in the propagation step, with syndiotactic propagation as a result.
Thermal oxidation of blends of poly(vinyl methyl ether) and modified polystyrenes
Authors: Park Hyunkil , Pearce Eli M. , Starnes W. H. , Kwei T. K.
Published: April 2003

Thermal oxidation of blends of poly(vinyl methyl ether) and styrene copolymers containing hydroxyl groups as hydrogen‐bond donors was studied. The hydrogen‐bonding interaction provide for improved miscibility between the component polymers and more extensive crosspropagation/cross‐termination reactions. In addition to their contribution to improved miscibility, phenol groups in the copolymers exhibited apparent antioxidant and prooxidant effects.
Structure changes on polymer blends by means of phase growth on microheterophase surface
Authors: Ishizu Koji , Minematsu Satoru , Fukutomi Takashi
Published: April 2003

We have studied the structural changes on poly(2‐hydroxyethyl methacrylate) (PHEMA)/polystyrene (PS) blends by means of phase growth of microheterophase pattern on a template surface composed of poly[2‐hydroxyethyl methacrylate (HEMA)‐g‐styrene (S)] graft copolymer (lamellar shape). The PS macromonomer was synthesized by free radical polymerization of S monomer initiated by a functional initiator [2,2'‐azobis(2‐(2‐imidazolin‐2‐yl)propane: VA‐061] in the presence of a degradative chain transfer agent, followed by an end‐capping reaction with p‐chloromethylstyrene (CMS). Poly(HEMA‐g‐S) graft copolymers were prepared by free radical copolymerization of these vinylbenzyl‐terminated PS macromonomers with HEMA comonomer.
Phase transfer Pd(O) catalyzed polymerization reactions. I. Synthesis of 1,2‐(4,4′;‐dialkoxyaryl) acetylene monomers and 1,4‐Bis[2‐(4′,4″‐dialkoxyphenyl)ethynyl]benzene derivatives by phase transfer Pd(O)/Cu(I) catalyzed coupling reactions
Authors: Pugh Coleen , Percec Virgil
Published: April 2003

Several 1,2‐(4,4'‐dialkoxyaryl)acetylene monomers containing similar or dissimilar substituents were prepared by one of three variations of a one pot phase transfer Pd(O)/Cu(I) catalyzed coupling of aryl halides with a protected acetylene. The three steps within a single flask involved first coupling of the appropriate 1‐halo‐4‐alkoxybenzene derivative with 2‐methyl‐3‐butyn‐2‐ol, followed by cleavage of the carbinol group to form an aryl acetylide, and finally a second coupling of an aryl halide with the aryl acetylide. Best results were obtained when elevated temperatures and solid‐liquid phase transfer reaction conditions were used. Some 1,4‐bis[2‐(4',4”‐dialkoxyphenyl)ethynyl]benzene compounds were also prepared.
End‐Functionalized polymers by living cationic polymerization. IV. Poly(vinyl ethers) with acidic or basic terminal groups by functional initiator method
Authors: Hashimoto Tamotsu , Takeuchi Etsu , Sawamoto Mitsuo , Higashimura Toshinobu
Published: April 2003

Carboxylic acid or primary amine‐terminated poly(isobutyl vinyl ethers) were synthesized by living cationic polymerizations with functionalized initiators (CH3CHIOCH2CH2  X; X: that are the adducts of the corresponding vinyl ethers (CH2  CH  OCH2CH2X) with hydrogen iodide. In the presence of iodine, these initiators induced living cationic polymerization of isobutyl vinyl ether to give polymers with the α‐end group of X originating from the initiators. The polymer molecular weights were regulated by the monomer to initiator feed ratio and the molecular weight distributions were very narrow (Mw/Mn ≤ 1.15). Subsequent deprotection of the terminal group X led to polymers with a terminal carboxylic acid or primary amine. 1H‐ and 13C‐NMR analyses showed that the end functionalities of these polymers were all close to unity.
Preparation of polyamide‐imides via the phosphorylation reaction. II. Synthesis of wholly aromatic polyamide‐imides from N‐[p‐(or m‐) carboxyphenyl]trimellitimides and various aromatic diamines
Authors: Hsiao Sheng‐Huei , Yang Chin‐Ping
Published: April 2003

Wholly aromatic polyamide‐imides with high molecular weight (ηinh up to 1.7 dL/g in DMAc–5% LiCl) were obtained by the direct polycondensation reaction of N‐[p‐( or m‐) carboxyphenyl]trimellitimide [p‐(or m‐)CPTMI] and aromatic diamines by means of di‐ or triphenyl phosphite in N‐methyl‐2‐pyrrolidone (NMP)‐pyridine solution in the presence of lithium or calcium chloride. The factors affecting the phosphorylation reaction were investigated, in particular for the reaction of p‐CPTMI and 4,4'‐oxydianiline (ODA). Molecular weight of polymers varied with the amount of metal salts and showed maximum values at the concentration of 10‐15 wt % in the reaction mixture. Monomer concentration of 0.2 mol/L produced polymer of the highest viscosity. Higher concentrations produced gelation and yielded polymers of low molecular weight. A reaction temperature of about 120°C gave the best results. Among the solvents tested, NMP was significantly the most effective for the reaction. The highest inherent viscosity values, ηinh = 1.35 and 1.58 dL/g, were obtained with triphenyl phosphite (TPP)/monomer and diphenyl phosphite (DPP)/monomer molar ratios of 2.0. Excessive addition of phosphites did not cause a serious deleterious effect on the molecular weight of polymer. Polycondensations of several combinations of p‐or m‐CPTMI and aromatic diamines were carried out with satisfactory results.
Photoinduced conformational changes of azoaromatic polyaspartates containing octadecyl side chains
Authors: Ueno Akihiko , Adachi Kayo , Nakamura Junko , Osa Tetsuo
Published: April 2003

Copolymers of p‐(phenylazo)benzyl‐L‐aspartate and n‐octadecyl‐L‐aspartate exist as right‐ and left‐handed α‐helices in solution at 25°C depending on the copolymer composition: the reversal of helix sense from a right‐ to left‐handed one occurs with increasing the azobenzene content. The α‐helices of the copolymers are very sensitive to trifluoroacetic acid (TFA), and are converted into random coil below 2.0% of TFA. Among the copolymers, the copolymer containing 47% azobenzene groups is unique since it exhibits a TFA‐induced conformational change from right‐handed α‐helix to random coil via left‐handed α‐helix. Upon UV light irradiation at 25°C, the copolymers containing 68 and 89% azobenzene groups caused the reversal in helix sense from a left‐ to right‐handed one. The conformations of the copolymers were dependent on temperature, mostly right‐handed and left‐handed α‐helices at lower and higher temperatures, respectively. On this basis, the copolymer containing 47% azobenzene groups could be made to undergo a photoinduced helix reversal at high temperatures.
Availability of surface hydroxyl groups in valonia and bacterial cellulose
Authors: Verlhac C. , Dedier J. , Chanzy H.
Published: April 2003

The chemical microstructural analysis (CMA) developed by Rowland and his school was applied to Valonia and bacterial cellulose and the results compared to those obtained with cellulose from cotton linters. It was found that the surface reactivity of Valonia was very small, roughly one half of that found for bacterial and cotton cellulose. Valonia and bacterial cellulose crystals were found to be of high surface perfection as their surface O(3)H was almost inaccessible. In contrast, in the cotton sample, this hydroxyl group was almost as accessible as in the fully disorganized native cellulose.
Bis(ethyl‐3‐Oxo‐Butanolato‐O1,O3) ‐bis(2‐propanolato)titanium (tyzor) DCR) as a reactant and catalyst in the polymerization of 2‐isocyanatoethyl methacrylate (IEM)
Authors: Graham John C. , Xu Xinmin , Jones Lonnie , Orticochea Margarita
Published: April 2003

The reaction of bis(ethyl‐3‐oxo‐butanolato‐O1,O3)‐bis(2‐propanolato)titanium(Tyzor DCR and 2‐isocyanatoethyl methacrylate (IEM) in refluxing hexane produced a mixture of trimer and polymers of 2‐isocyanatoethyl methacrylate which varied considerably from 23 to 92% polymer as the molar ratio of bis(ethyl‐3‐oxo‐butanolato‐O1,O3)‐bis(2‐propanolato)titanium(Tyzor DCR) to 2‐isocyanatoethyl methacrylate (IEM) varied from 1:4 to 1:32. The IEM 1‐nylon polymer which was soluble in cresol and phenol was characterized by FTIR, 1H‐NMR, and 13C‐NMR. This analysis also showed that the methacrylate carbon–carbon double bond survived our reaction conditions intact. Based on atomic absorption determination of titanium, the molecular weight of the polymer ranged between 3000 and 4000 g/mol. Thermal gravimetric analysis (TGA) showed the polymer to be stable in air to approximately 250°C.
Mechanism of radiation‐induced degradation of poly(methyl methacrylate) as studied by ESR and electron spin echo methods
Authors: Ichikawa Tsuneki , Yoshida Hiroshi
Published: April 2003

The role of radical species in the degradation of poly(methyl methacrylate) (PMMA) induced by γ‐irradiation has been studied by means of electron spin resonance and electron spin echo spectroscopy. The major radical species generated initially at 77 K are assigned to main chain  CH  and side chain  COOCH2 radicals, and  COOCH anion radical. Only the  COOCH2 radical converts to the scission‐type  CH2  C(CH3)COOCH3 radical on warming the sample of >180 K. A part of the  CH  radical disappears on warming the sample of >265 K. It is concluded that the scission of PMMA main chain occurs by the intramolecular process from the  COOCH2 radical as the precursor state.
Living polymerization of aryl substituted acetylenes by MoCl5 and WCl6 based initiators: The ortho phenyl substituent effect
Authors: Kunzler Jay , Percec Virgil
Published: April 2003

The polymerization of phenylacetylene initiated by MoCl5 and WCl6 based initiators was monitored directly in the NMR sample tube and demonstrated the presence of backbiting and intramolecular cyclization reactions. It was shown that the ratio of cis to trans structural units obtained by isomerization prior to double bond formation dictates the degree of backbiting and intramolecular cyclization reactions. This cis–trans ratio determines the length of cis–transoidal sequences present in the polymer backbone which are available for both backbiting and intrachain cyclization reactions. The cyclic trimers obtained in the metathesis polymerization of phenylacetylene are formed only through the cis–cisoidal‐induced backbiting and/or intramolecular reactions. The o‐trimethylsilylphenylacetylene follows a living mechanism of polymerization. This is due to the fact that the size of the ortho substituent suppresses the cis–transoidal to cis–cisoidal isomerization reactions and therefore eliminates the backbiting reactions. The steric hindrance provided by the size of the ortho substituent also eliminates interchain and intrachain reactions.
Synthesis of new amphiphilic block copolymers. Block copolymer of sulfonated glycidyl methacrylate and alkyl methacrylate
Authors: Leemans L. , Fayt R. , Teyssié Ph.
Published: April 2003

Water‐soluble amphiphilic block copolymers consisting of a hydrophobic block of poly(alkyl methacrylate) and a hydrophilic anionic polyelectrolyte block have been synthesized by a living anionic polymerization of methyl methacrylate and glycidyl methacrylate and subsequent selective modification of the oxirane groups of the glycidyl methacrylate block into hydroxysulfonate groups by a phase transfer catalyzed sulfonation reaction. The block copolymers were characterized by a predictable motecular weight and a narrow molecular weight distribution while the yield was quantitative. These amphiphilic block copolymers display surfaceactive behavior in water and they are characterized by a critical micelle concentration.
Further studies on homopolymers and copolymers resulting from the reaction of polymaleic anhydride with alcohols and amines
Authors: Tsiourvas D. , Paleos C. M. , Dais Photis
Published: April 2003

Polymaleic anhydride prepared by γ‐rays irradiation of maleic anhydride was used as a reactive polymer and reacted with certain long‐chain aliphatic amines and/or alcohols as well as with the mesogenic biphenylamine. The homopolymers and copolymers that were prepared, i.e., derivatives of N‐alkyl polymaleamic acid, monoesters of polymaleic acid, or mixed amide‐ester derivatives, were primarily investigated as far as their property to show thermotropic liquid crystalline character is concerned. By this investigation the structural features for the exhibition of mesomorphism by these polymers were determined.
Chemical modification of polynorbornene. II. Extended sulfonation processes
Authors: Planche J. P. , Revillon A. , Guyot A.
Published: April 2003

In the sulfonation of polynorbornene in dilute solution, the nature of the sulfonation agent mainly influences the reaction rate, according to its strength and also affects some side reactions (chain scission and crosslinking). The sulfonation can be carried out in suspension after swelling the highly porous powder in dichloroethane up to a 55% sulfonation ratio with preservation of the initial particular nature of the polymer; the latter may be then either partly or totally water soluble, depending on the initial size of the particles. Partial sulfonation, leading to ionomers, may be carried out in bulk at moderate temperature, in a mixing chamber, after gelification of the polymers, plasticized with CCl4.
Block interrupt polysilane derivatives
Authors: Miller R. D. , Fickes G. N.
Published: April 2003

High molecular weight block interrupt polysilane derivatives have been prepared by the condensation of a number of α,ω‐dichloropolysilanes with some aromatic bis silanols. In this manner, polymers containing polysilane blocks of 2, 4, or 6 catenated silicon atoms have been prepared. The materials are thermally stable and the UV spectroscopic properties mimic those of the corresponding monomers. Although these materials bleach upon irradiation in the deep UV, surprisingly, the block interrupt polysilanes behave as negative resists upon exposure to 254 nm radiation. This behavior contrasts with that of standard polysilane homopolymers which usually function in a positive lithographic mode.
The preparation and γ‐ray sensitivity of comb block copolymers
Authors: Laivins G. , Worsfold D. J.
Published: April 2003

A series of comb block copolymers have been prepared and subjected to 60Coγ irradiation. The copolymers contained a polyalkenesulphone backbone, and either polystyrene or polymethylphenylsiloxane as the sidebranches. The alkenes in the polysulphone were one of cycloheptene, 2‐hexene, or 2‐methylpentene‐1 giving a series of backbones of differing low ceiling temperatures. The combs were prepared by creating a macromer of the desired sidearm, and then copolymerizing into the main chain. On γ‐irradiation, backbone polysuphones depolymerized leaving behind the comparatively short and radiation resistant sidechains.
Function of vinyl copolymers with pendant porphyrin or metalloporphyrin dimers as photoredox catalyst
Authors: Kamogawa Hiroyoshi , Minoura Shuuji , Miyama Shingo
Published: April 2003

Photoredox catalytic functions of water‐soluble vinyl copolymers with pendant porphyrin or metalloporphyrin dimers were investigated. With FRA‐L‐ascorbic acid in aqueous solution, a vinyl copolymer bearing Mg‐porphyrin dimer linked with the shortest N,N′‐methylenebisamide bridge was found to have a remarkable accelerating effect under illumination of visible light as compared with that bearing Mg‐porphyrin monomer and other copolymers with longer dimer bridges as well as vinyl copolymers bearing porphyrin dimers and monomer. A copolymer bearing Zn‐porphyrin dimer was much inferior to that bearing monomer. Copolymers with other metals such as Co(II), Ni(II), and Cu(II) were almost inert.
4‐N,N‐Dimethylamino‐4'‐Isopropylbenzophenone as polymerization photoinitiator. Effect of solvent and photoinitiator concentration on its photoreactivity and on the polymerization process
Authors: Mateo J. L. , Bosch P. , Catalina F. , Sastre R.
Published: April 2003

Several kinetics aspects of the methyl methacrylate (MMA) polymerization using 4‐dimethylamino‐4'‐isopropylbenzophenone (PI) as photoinitiator have been studied. The order of the polymerization reaction with respect to monomer and initiator concentrations have been investigated, as well as the polymerization behavior under well‐stirred and unstirred conditions; values of initiation quantum yield (ϕi) and kp/kt1/2 have also been determined. It has been found that the nature of the polymerization‐initiating radicals depends on the type of solvent and the photoinitiator concentration ([PI]). In cyclohexane solution and at low [PI] (< 5 x 10‐5M), the cyclohexyl radical is practically the only polymerization initiating radical, while at higher [PI] both radicals, cyclohexyl and the aminoalkyl derived from PI, participate in the initiation step, increasing the participation of the later as the [PI] increases. When benzene is used as solvent both phenyl and aminoalkyl radicals participate in the initiation step at any [PI] employed. Efficiencies of the radicals derived from solvent and photoinitiator have been determined.
Polyurethane elastomers with hydrolytic and thermooxidative stability. I. Polyurethanes with N‐alkylated polyamide soft blocks
Authors: Chapman Toby M. , Rakiewicz‐Nemeth Donna M. , Swestock John , Benrashid Ramazan
Published: April 2003

Segmented polyurethanes with N‐alkylated amides as soft blocks as prepared. Comparisons are made with both a poly(ester urethane) and a poly(ether urethane) with the same hard block; the poly(amide urethane) is more hydrolytically stable than the polyester containing material and demonstrates greater thermooxidative stability than that with the polyether moiety. The aliphatic poly(amide urethane)s remain transparent upon exposure to uv light.
Studies of the photolysis of aromatic esters in solution and in polymer films
Authors: Holdcroft Steven , Yuen Kenneth H. , Guillet James E.
Published: April 2003

Photolysis of 2‐naphthylenemethyl‐1‐naphthylacetate (NMNA) and 9‐anthracenemethyl‐9‐anthrylacetate (AMAA) yields radicals of methylnaphthalene and methylanthracene, respectively. The longevity of these radicals makes them suitable probes for studying primary and secondary cage recombination processes in solution, and in polymeric matrices. 2,2‐Di‐(4‐tert‐octylphenyl‐1‐picrylhydrazyl) (DPPH) is utilized as a radical trap to report on radicals which escape from the solvent cage. Quantum yields for photolysis of NMNA and AMAA were determined in solution and in poly(methyl methacrylate) films. Both unimolecular and bimolecular processes are suppressed as a result of the greater effective viscosity in polymeric media.
Synthesis of poly(alkylene phosphate)s with n‐containing bases in the side chains. III. N1‐Oxoethyleneuracil on the poly(trimethylene phosphate) chain
Authors: Łapienis Grzegorz , Penczek Stanisław
Published: April 2003

Poly(2‐hydro‐2‐oxo‐1,3,2‐dioxaphosphorinane) was quantitatively chlorinated, and the resulting polymer was reacted with excess of imidazole, giving the highly reactive polyesteramide. This polymer, treated with N1‐hydroxyethyluracil, gave polyphosphates with N1‐oxoethyleneuracil in the side chains. The final polymers (M̄n ≈ 104) as well as the intermediate products were characterized by 1H‐, 13C‐ and 31P‐NMR spectroscopy.
Inclusion polymerization of 1‐chlorobutadiene in a deoxycholic acid canal
Authors: Tsutsumi Hiromori , Okanishi Ken , Miyata Mikiji , Takemoto Kiichi
Published: April 2003

Inclusion polymerization of 1‐chlorobutadiene was studied using 3α,12α‐dihydroxy‐5β‐cholan‐24‐oic acid (deoxycholic acid, DCA) as host molecules. It was found that the poly(1‐chlorobutadiene) had almost 100% of head to tail, trans‐1,4‐structure on the basis of 13C‐NMR and IR spectroscopies. This was the first example of preparing the highly regulated poly(1‐chlorobutadiene) by using the inclusion polymerization technique. The polymers obtained were optically active and the maximum value of specific rotation was [α]D‐41.9°. Both the rate constants and the value of activation energy of the elementary reactions of inclusion polymerization of 1‐chlorobutadiene were determined by graphical evaluation. The activation energy of propagation and termination was 11.7 and 11.1 kcal/mol, respectively.
Studies of reactions with polymers. VI. The modification of PAN with primary amines
Authors: Chiang Wen‐Yen , Hu Chun‐Min
Published: April 2003

A series of modified polyacrylonitriles have been obtained with several primary amines, such as ethanolamine, ethylenediamine, ethylamine, n‐butylamine, and n‐octylamine, without any catalysts in DMSO. This paper presents the syntheses of these new modified polymers and discusses the resultant structures and reaction mechanism by IR, NMR, and UV spectra. Composition was obtained by elemental analysis. Moreover, some physical properties of polymer were also investigated. It was found that all these primary amines could initiate coloration of polyacrylonitrile, which involves linking up of adjacent nitrile groups, and also reactions of the amines with the nitrile groups. However, the product of polyacrylonitrile with ethanolamine and with ethylenediamine were soluble in water when the mole ratio of amine group to nitrile group was 2. This interesting fact promoted a more detailed study of the modification of polyacrylonitrile with these amines. Crosslinking of the products of PAN with ethanolamine (or with ethylenediamine) was achieved by heat treatment. A mechanism for the formation of crosslinking was proposed.
Synthesis and polymerization of ethyl α‐chloromethylacrylate and related derivatives
Authors: Warren Stephen C. , Mathias Lon J.
Published: April 2003

Ethyl α‐hydroxymethylacrylate (EHMA) was synthesized from ethyl acrylate and paraformaldehyde, and converted to ethyl α‐chloromethylacrylate (ECMA) by reaction with thionyl chloride. ECMA was bulk polymerized at 65°C with α,α′‐azobis(isobutyronitrile) (AIBN) to give a homopolymer with a viscosity of 0.084 dL/g. Spontaneous polymerization at ambient temperature surprisingly gave material with an intrinsic viscosity of 0.45 dL/g. Combined size exclusion chromatography‐laser light scattering in THF for the former gave Mn = 21,900, Mw = 26,500, and Mz = 34,340 with a dn/dc = 0.079 mL/g. The homopolymer of ECMA was substituted with octadecyl mercaptan in THF using solid NaOH and Aliquat 336 as base and catalyst, respectively. Copolymers of ECMA with styrene were synthesized by free radical polymerization with relatively high conversion. Copolymer compositions were determined using proton NMR and were found to be similar to feed ratios as expected for high conversion products. Both copolymers were reacted with 2‐ethyl‐2‐oxazoline (1:50 mole ratio) in an attempt to graft the oxazoline onto the polymer chain with only limited success. Two potential monomers were synthesized by reacting ECMA with 2‐ethyl‐2‐oxazoline neat and octadecyl mercaptan in CHCl3 using triethylamine as a catalyst. Neither material polymerized under normal radical conditions. Characterization of monomers and polymers involved FTIR and 13C NMR spectroscopy, differential scanning calorimetry, viscosity, and size exclusion chromatography‐laser light scattering.
One‐phase supported titanium‐based catalysts for polymerization of ethylene and its copolymerization with 1‐alkenes. I. Preparation and properties of catalysts
Authors: Salajka Zdeněk , Kratochvíla Jan , Hamřík Oldřich , Kazda Antonín , Gheorghiu Mihnea
Published: April 2003

Active one‐phase Ti‐based supported catalysts were prepared by interacting the activated silica gel (0.8 mmol OH groups/g) with RxAlCl3–x (x = 1–3, Al/OH = 0.9–1.0), then with TiCl4 and R2Mg (Mg/Ti = 1–16), and finally with R3Al (Al/Ti = 0–16). The catalyst activity in the fluid bed ethylene polymerization varied between 40 and 540 kg PE/g Ti h, depending on the component used and preparation conditions employed. A mechanism of the polymerization‐active species formation was proposed.
Synthesis and characterization of oxyethylene containing diisocyanates and polyimides therefrom
Authors: Avadhani C. V. , Wadgaonkar P. P. , Vernekar S. P.
Published: April 2003

A facile synthesis of a series of oxyethylene containing diisocyanates, the α,ω‐bis(isocyanatophenoxy)alkanes and bis[2‐(isocyanatophenoxy)ethyl] ethers, is described. The key step involves the uneventful decomposition of the corresponding diacylazides to the diisocyanates in the Curtius rearrangement reaction. Further, eight thermally stable oxyethylene containing polyimides were synthesized by the polycondensation reaction of two meta‐ and two para‐oriented diisocyanates, namely, 1,2‐bis(3‐isocyanatophenoxy)ethane and 1,2‐bis(4‐isocyanatophenoxy)ethane, and bis[2‐(3‐isocyanatophenoxy)ethyl] ether and bis[2‐(4‐isocyanatophenoxy)ethyl] ether, with pyromellitic dianhydride (PMDA) and benzophenonetetracarboxylic dianhydride (BTDA) in N,N‐dimethylacetamide (DMAc). These polyimides were characterized by IR spectroscopy, x‐ray diffraction, viscosity measurements, and thermogravimetric analysis.
Preparation and properties of new aromatic polyamides from 4,4′‐diaminotriphenylamine and aromatic dicarboxylic acids
Authors: Oishi Yoshiyuki , Takado Hiroko , Yoneyama Masaru , Kakimoto Masa‐Aki , Imai Yoshio
Published: April 2003

New aromatic polyamides (aramids) having inherent viscosities of 0.5–2.6 dL/g were prepared by the direct polycondensation of 4,4′‐diaminotriphenylamine with various aromatic dicarboxylic acids in N‐methyl‐2‐pyrrolidone using triphenyl phosphite and pyridine as condensing agents. These aramids were amorphous and soluble in a variety of solvents such as N,N‐dimethyl‐acetamide, dimethyl sulfoxide, and pyridine, and afforded transparent and tough films by solvent casting. The glass transition temperatures of these aramids were in the range of 280–310°C, and the 10% weight loss temperatures were above 430°C in air.
Esters of α‐sulfomaleic anhydride as powerful electrophiles for polyolefin functionalization
Authors: Schaedeli Ulrich , Padias Anne Buyle , Brois S. J. , Thaler Warren A. , Hall H. K.
Published: April 2003

New electrophilic derivatives of maleic anhydride were synthesized to test their reactivity in ene reactions with the terminal double bond of hydrocarbon polymers. The methyl ester and new ethyl ester of sulfomaleic anhydride (SMA) were reacted with 2,2,4‐trimethyl‐1‐pentene 3, which is a model compound for the end group of the hydrocarbon polymers. The SMA esters were more oleophilic than SMA itself, but many side reactions occurred. Higher alkyl esters of SMA could not be synthesized. Two silyl esters of SMA, trimethylsilyl and t‐butyldiphenylsilyl, were also synthesized and reacted with 3; ene reactions proceeded well in bulk, but the ene adducts decomposed upon heating. The powerful dienophilic character of these SMA esters was demonstrated by a series of [4 + 2] cycloadditions.
Aggregation of poly(vinyl acetate) or n‐decyl group grafted poly(allylamine) and crosslinking of trunk sequence in selective solvents
Authors: Saito Reiko , Ishizu Koji , Nose Takuhei , Fukutomi Takashi
Published: April 2003

Poly(allylamine‐g‐vinyl acetate) [P(AAm‐g‐VAc), VAc content 33 mol%] and poly(allylamine‐g‐n‐decane) [P(AAm‐g‐CH), number of n‐decyl group/allylamine molecule was 4.4] were prepared by redox initiation of vinyl acetate polymerization on poly(allylamine) or a condensation reaction between amino group and 1‐bromo‐n‐decane. These polymers form aggregate in mixed solvents tetrahydrofuran/H2O and acetone/H2O. In acetone/H2O at a volume ratio which is good for poly(vinyl acetate) and not for poly(allylamine) (v/v = 65/35), the distribution of particle diameter shows a bimodal profile. These peaks vary with polymer concentration in the case of P(AAm‐CH). Poly(allylamine) sequences were crosslinked by 1,3‐dibromo‐2‐propanol in this solvent without macrogel formation. The crosslinking of particles with large diameter (several hundred nm) formed in rather concentrated solution was shown by electron micrograph. It was revealed that phase separation occurred in a particle with the proceeding of crosslinking reaction.
A study of the properties and topological trapping of cyclic poly(dimethylsiloxane) in poly(2,6‐dimethyl‐1,4‐phenylene oxide) networks
Authors: Huang W. , Frisch H. L. , Hua Y. , Semlyen J. A.
Published: April 2003

Polymeric catenanes have been made from poly(2,6‐dimethyl‐1,4‐phenylene oxide) crosslinked in the presence of several, paucidisperse poly(dimethylsiloxane) cyclics of varying degrees of polymerization. The fraction of cyclic threaded or captured by the polymer network increases as the degree polymerization of the cyclic increases in good agreement with the crude estimates of Frisch and Wasserman. Thermal analysis and electron micrographs reveal microphone separation in all of the polymeric catenanes; with PDMS domain size around 10–50 μ. Most of the catenanes exhibit a lower tensile strength to break than the pure crosslinked PPO.
Electrochemical polymerization of 3‐octylpyrrole
Authors: Masuda Hideyuki , Tanaka Susumu , Kaeriyama Kyoji
Published: April 2003

Electrochemical polymerization of 3‐octylpyrrole (OCPY) yielded a film on the anode. Its conductivity was 5 S/cm. Infrared spectra of OCPY and poly(3‐octylpyrrole) (POCPY) were compared with those of related monomers and polymers, and as a result, the pyrrole rings appeared quite likely linked at 2‐ and 5‐positions. Cyclic voltammograms of a PF–6‐doped POCPY film had an anodic peak at 0.16 V vs. Ag and a cathodic peak at 0.12 V. Doped POCPY was stable and soluble in such polar solvents as tetrahydrofuran, N‐methylpyrrolidinone and pyridine. Although the absorption spectrum of the film had three peaks at 1.0, 2.5 and 3.6 eV, as also in the case of poly(3‐methylpyrrole), the spectra in pyridine and THF solutions indicated two peaks at 1.9 and 3.2 eV. Scanning electron microscopy (SEM) showed the POCPY films to have a unique morphology, depending on the electrolytes used for electrochemical polymerization. The introduction of an octyl group made polypyrrole soluble in organic solvents, but effective conjugation length became shorter and the texture of films rougher.
Preparation and polymerization of spiroorthoester bearing the perfluoroalkyl group
Authors: Yokozawa Tsutomu , Sato Makoto , Endo Takeshi
Published: April 2003

For a potential use of spiroorthoesters which polymerize with essentially zero shrinkage during polymerization, the preparation of spiroorthoester (I) bearing the perfluoroalkyl group was carried out. Spiroorthoester I was prepared by the reaction of ε‐caprolactone with 2‐(F‐octyl)ethyl glycidyl ether (II), obtained from 2‐(F‐octyl)ethanol and epichlorohydrin, in the presence of catalytic amount of BF3OEt2. Spiroorthoester I underwent the cationic ring‐opening polymerization by virtue of BF3OEt2 to obtain poly(ether‐ester) with 2.7% expansion on polymerization. The presence of the perfluoroalkyl group had no significant effect on the polymerization of the spiroorthoester.
Photocrosslinking of polyethylene. III. Thermal oxidative stability of photocrosslinked polyethylene
Authors: Chen Yong Lie , Rånby Bengt
Published: April 2003

The thermal oxidative stability of photocrosslinked high density polyethylene was studied. The relative effectiveness of various antioxidants (hindered phenols and amines, aromatic amine, organic sulfides, and phosphites) was examined by comparing the oxidation induction time (OIT) which was measured using differential scanning calorimetry. Hindered phenol antioxidants were found to be most effective. At an antioxidant concentration of 0.20 wt % which gave an OIT value of 20 min at 200°C, the photocrosslinking rate was decreased only to a limited extent as evidenced by a small drop in gel content. However, the efficiency of the antioxidants as stabilizers decreased to a considerable extent after the photocrosslinking process. Serious surface deterioration was found which was ascribed to depletion of antioxidant at the surface mainly due to high rate of oxidation and evaporation.
Synthesis and properties of polyamine resins from epoxy resins
Authors: Yang Chin‐Ping , Lee Lung‐Ta
Published: April 2003

Polyamine resins were synthesized by the preparation of ketimine‐terminated resins from epoxy resin and ketimine blocked diethylene triamine (1) and subsequent hydrolysis. 1 was prepared by the condensation reaction of diethylene triamine with methyl isobutyl ketone catalyzed by acid. The hydrolysis of ketimine containing resin was evaluated by the change of the pH value of reaction mixture and the infrared spectroscopy and gel permeation chromatography curve of the resulting product. The hydrolytic rate of ketimine increased with the increase of temperature or the amount of acid added. The crosslinking, emulsion, and electrodeposition properties of these polyamine resins were studied in some detail.