bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of crystallizable comb‐like oligomers by coupling of stearyl acrylate to butadiene oligomers via ene reaction and the influence of side‐chain order on the network formation by autoxidation
Authors: Luchtenberg Jürgen , Ritter Helmut
Published: April 2003

The kinetics of the ene reaction of stearyl acrylate with polybutadiene oils in the temperature range of 180 to 220°C is described. The ene reaction was found to be of pseudo 1st order with respect to stearyl acrylate because of the excess of polybutadiene double bonds. The rate constants correlate with the reaction temperature according to the Arrhenius law. The products show typical side‐chain crystallization, which has a strong influence on the viscosity and the autoxidation kinetics of the unsaturated polymeric backbone. Just below the crystallization temperature of the side chains the network formation by autoxidation is much slower than above the melting point.
(Co)polymers of L‐lactide, 1. Synthesis, thermal properties and hydrolytic degradation
Authors: Grijpma Dirk W. , Pennings Albert J.
Published: April 2003

Copolymers of L‐lactide with D‐lactide

According to IUPAC the name dilactide is preferred to lactide.

, glycolide

IUPAC name: diglycolide.

, ε‐caprolactone and trimethylene carbonate, and networks with spiro‐bis‐dimethylene‐carbonate (2,4,7,9‐tetraoxaspiro[5.5]undecane‐3,8‐dione) were prepared in bulk at standardized polymerization conditions. The properties of the nascent copolymers were evaluated with respect to the nature of the comonomer. Copolymerization with comonomers entailing low glass transition temperature simultaneously reduces the crystallinity. 300 MHz 1H nuclear magnetic resonance is shown to be a useful technique for the determination of the average monomer sequence lengths in ε‐caprolactone and trimethylene carbonate copolymers. The presence of crystallizable L‐lactide sequences, due to differences in monomer reactivity, has a large effect on the thermal properties of the copolymer as well as on the long‐term degradation characteristics.
Synthesis of graft polymers from an ozonised ethylene‐vinyl acetate copolymer, 2. Determination of the efficiency and of the decomposition rate of macroinitiators
Authors: Fargère Thierry , Abdennadher Mohamed , Delmas Michel , Boutevin Bernard
Published: April 2003

Polymers can be treated with an ozone/oxygen mixture to create peroxide and hydroperoxide groups on the polymer chain. These heat‐sensitive functional groups can serve to initiate radical polymerization of vinyl monomers to form graft copolymers. The efficiency and the decomposition rate constant of an ozonized ethylene‐vinyl acetate copolymer (EVA) are determined using the polymerization rate of styrene. The thermal polymerization of styrene is studied in the presence of non‐ozonized EVA. The thermal polymerization has no effect on the polymerization of styrene at the beginning of the reaction. Transfer reactions between the growing polystyrene radical and the EVA chain are negligible. The activation energy of the decomposition rate of ozonized EVA is calculated and reaches 46 kJ/mol. The entropy variation of the decomposition reaction is also calculated. The result obtained shows an important decrease (−45 cal · mol−1 · K−1) of the entropy which is opposite to the common behaviour (−6 to +13 cal · mol−1 · K−1) expected. The efficiency observed for the ozonized polymers is low and reaches only 20% at 100°C, this can be explained by the lack of mobility of the created radicals.
Functionalized polysulfones from 4,4‐bis(4‐hydroxyphenyl)pentanoic acid, 2,2‐isopropylidenediphenol and bis(4‐chlorophenyl) sulfone: synthesis, behaviour and polymer analogous amidation of the carboxylic groups
Authors: Koch Thomas , Ritter Helmut
Published: April 2003

Two reactive polysulfones with carboxylic side groups were synthesized by polycondensation of different amounts of 4,4‐bis(4‐hydroxyphenyl)pentanoic acid (1) and 2,2′‐isopropylidenediphenol (bisphenol‐A,2) with bis(4‐chlorophenyl) sulfone (3). The amorphous polycondensate 4a was cast from solution in N,N‐dimethylformamide (DMF) to produce a homogeneous membrane which is clear and colourless. With ethanol/water as permeate, preferred permeability of water occurs. Additionally, the carboxylic groups of 4a were condensed with several alkylamines via the acyl chlorides. The obtained polysulfones with pendant alkylamido groups show a strong dependence of the glass transition temperature on the side chain length.
Anisotropic binders for polymer/liquid crystal dispersions
Authors: Cada Leonorina G. , Chien Liang‐Chy
Published: April 2003

The synthesis and phase behavior of linear and crosslinked side‐group epoxy polymers are described. These polymers are used in dispersons with low‐molecular‐weight liquid crystals, and the observation of phase separation in these systems is demonstrated.
Cationic polymerization of bis(1‐alkylvinyl)benzene and related monomers, 7. Copolymers
Authors: Maier Gerhard , Nuyken Oskar , Leitner Michael B.
Published: April 2003

Polyindanes with long alkyl side chains have been prepared by reaction of 1,4‐bis(2‐hydroxy‐2‐propyl)benzene (3) and 1,4‐bis(2‐hexadecen‐2‐yl)benzene (4) in various ratios. All copolymers are soluble in common organic solvents and have been characterized by NMR, IR, GPC, DSC and TG. The variation of the glass transition temperature Tg with the composition of the copolymers can be described satisfactorily by Couchman's equation, which describes the dependence of the Tg's of copolymers on the Tg's and heat capacities of the homopolymers and the weight fractions of the comonomers in the copolymers. A very important feature of this step‐growth copolymerization is the ability of all possible end‐groups of monomers and oligomers to react with each other. Therefore the composition of the copolymers is not governed by the composition of the feed, because there is no need for high conversion to obtain high molar mass. It was found that 3 was twice as reactive as 4. The experimentally determined composition of the copolymers is in good agreement with the calculations based on the differences in the reactivity of the monomers.
Novel structural and thermotropic behavior of poly(diphenylphosphazene)
Authors: Kojima Morio , Magill Joseph H. , Cypryk Marek , White Michael L. , Franz Uli , Matyjaszewski Krzysztof
Published: April 2003

Poly(diphenylphosphazene) (PDPhP) was synthesized by a reaction of 2,2,2‐trifluoroethyl diphenylphosphinite with trimethylsilyl azide. Characteristics of the polymer exhibit a marked molecular weight dependency. DSC measurements showed that the PDPhP undergoes a mesophase T(1) type transition in the range 180 ∼ 190°C and another at 240 ∼ 255°C depending upon the molecular weights of the polymers. Upon heating and cooling through T(1) the higher molecular weight PDPhP transforms to a 3D orthorhombic (γ‐form) with a = 1,99 nm, b = 1,05 nm and c = 0,995 nm from its original form (α‐form) in which a = 1,01 nm, b = 1,01 nm and γ = 101° after passing through the disordered mesophase (δ‐form). Another 3D form (β‐form) with c = 1,25 nm is formed from the lower molecular weight PDPhP after heat treatment of the 2D phase (δ‐form) that is obtained by quenching the specimens into ice‐water (4°C) from above T(1). The conditions for the formation of the β‐form depend strongly on the polymer molecular weight and its history. Lath‐shaped crystals were grown from dilute dichlorobenzene solution by adding p‐xylene (a non‐solvent). Electron diffraction patterns of solution grown PDPhP specimens exhibit unusual hexatic triple reflections associated with the mesophase. (100) twinning due to the thermal history of the specimens has been established. A complex (multistep) heat treatment process was required to elucidate the transformation behavior in PDPhP.
The synthesis and characterization of polyesters based on 2,5‐pyridinedicarboxylic acid
Authors: East George C. , Gudiguntla Venu G. R.
Published: April 2003

A series of novel polyesters based on 2,5‐pyridinedicarboxylic acid were synthesized using the reaction of the caesium salt of the acid with a variety of dibromo compounds in N‐methyl‐2‐pyrrolidone at 110°C. For the α,ω‐dibromoalkane Br(CH2)mBr series, the efficiency of the polymerization increases as the chain length increases, the highest weight‐average molecular weight of M̄w ≈ 47000 being obtained for the polymer with m = 10. All the polyesters were characterized by means of infrared and nuclear magnetic resonance spectroscopies, as well as elemental analysis. Solubility and thermal properties of these polyesters were determined and compared with their terephthalate analogues. The presence of the 2,5‐pyridinediyl unit improved the solubility behaviour and decreased the thermal stability. Compared to the analogous terephthalates, the polymers showed slightly higher glass transition temperature and lower melting temperature values.
Polymerization of 3,5,5‐trimethyl‐1‐hexene with Ziegler‐Natta catalysts
Authors: Endo Kiyoshi , Fujii Kazuyoshi , Otsu Takayuki
Published: April 2003

Polymerization of 3,5,5‐trimethyl‐1‐hexene (TM1H) with TiCI3 and alkylaluminium catalysts was studied. TM1H can be polymerized, but the polymerization rate is quite low due to the bulky substituent of the side chain. During the polymerization of TM1H, the isomerization of TM1H to internal olefins was observed. The overall activation energy for polymerization of TM1H was estimated to be approx. 37 kJ/mol. By adding optically active L‐menthol to the TiCI3‐(i‐C4H9)3AI catalyst, a stereoelective polymerization was induced. Monomer‐isomerization copolymerization of TM1H and trans‐2‐butene took place, giving copolymers consisting of the corresponding 1‐olefin units.
Surface characterizations of copolymer films with pendant monosaccharides
Authors: Nakamae Katsuhiko , Miyata Takashi , Ootsuki Norihito , Okumura Masakazu , Kinomura Keisake
Published: April 2003

We copolymerized a monomer with a pendant glucose unit (GEMA) with methyl methacrylate (MMA) and prepared copolymer films with pendant monosaccharides by casting the copolymer solution on glass plates. The surfaces of the copolymer films were characterized by contact angle measurements, X‐ray photoelectron spectroscopy (XPS) and protein adsorption measurements, and compared with the surface of 2‐hydroxyethyl methacrylate (HEMA)‐MMA copolymer films. The surface free energy of the GEMA‐MMA and HEMA‐MMA copolymer was calculated from the contact angle of methylene diiodide and glycerol on the copolymer films. The surface free energy of the films increased gradually with increasing GEMA or HEMA content. The surface free energy of GEMA‐MMA copolymers was larger than that of HEMA‐MMA copolymers in the whole range of composition. The results of XPS measurements suggest that the fraction of GEMA at the copolymer surface increases as the content of GEMA in the copolymer increases. This indicates that introduction of GEMA makes the copolymer surface more hydrophilic. Further more, the higher the GEMA content is, the smaller amounts of fibrinogen and γ‐globulin are adsorbed at the copolymer surface. The copolymer with a GEMA content of 20 mol‐% hardly adsorbs fibrinogen and γ‐globulin at all.
Study of the miscibility of poly(N‐vinyl‐2‐pyrrolidone) with poly[styrene‐co‐(4‐hydroxystyrene)]
Authors: Zhu K. J. , Liqun Wang , Ji Wang , Shilin Yang
Published: April 2003

Poly(N‐vinyl‐2‐pyrrolidone) (PVP) was blended with poly[styrene‐co‐(4‐hydroxytyrene)] (PSH) which was obtained from the random copolymer poly[styrene‐co‐(4‐acetoxystyrene)] (PSA). The miscibility of PVP/PSH blends in a composition 1 : 1 by weight was evaluated by differential scanning calorimetry (DSC), non‐radiative energy transfer (NET) and Fourier transform infrared (FTIR) spectroscopy. It was found that the blends become miscible when the hydroxystyrene units (HS) in PSH exceed 11 mol‐%. The driving force of miscibility may be attributed to hydrogen bonding between OH in PSH and in PVP. The experimental results of miscibility were compared with that estimated from a “miscibility parameter” (MP) concept, and we found that the general trend of MP values is in agreement with the experimental results.
Poly(phthalidylidenearylene)s. Effect of pressure on the conductivity of poly(3,3‐phthalidylidene‐4,4′‐biphenylylene)
Authors: Zolotukhin Mikhail G. , Lachinov Alexey N.
Published: April 2003

Poly(3,3‐phthalidylidene‐4,4′‐biphenylylene) (PPB) was considered to be a polymer containing pressure‐sensitive moieties as repeating units in the main chain. The effect of pressure on the properties of PPB was studied. Thin films of the undoped polymer were found to become conductive under slight pressure. The conductivity increases from 10−14 up to 10−3 Ω−1 · cm−1 under a pressure of about 3 · 105 Pa (0,3 kg/cm2). An effective method is used to visualize the pattern of conducting sites. These may be represented by channels (or domains) in the polymer film.
Modifications in the mesogenic unit of poly(oxytetramethyleneoxycarbonyl‐3‐chloro‐1,4‐phenyleneoxyterephthaloyloxy‐2‐chloro‐1,4‐phenylenecarbonyl)
Authors: del Pino Javier , Gómez Marian A. , Ellis Gary , Marco Carlos , Fatou José G.
Published: April 2003

The effect of asymmetrical chlorine substitution in the mesogenic unit of poly(oxytetramethyleneoxycarbonyl‐3‐chloro‐1,4‐phenyleneoxyterephthaloyloxy‐2‐chloro‐1,4‐phenylenecarbonyl) (1) has been studied by means of differential scanning calorimetry, optical microscopy and X‐ray diffraction. The polymer presents three‐dimensional ordering, in spite of the substitution, and shows a transition to a nematic mesophase at 274°C and to the isotropic melt at 319°C. As for the unsubstituted polymer poly(oxytetramethyleneoxycarbonyl‐1,4‐phenyleneoxyterephthaloyloxy‐1,4‐phenylenecarbonyl), two different crystalline forms have been observed and some information about their structure has been obtained by Fourier‐Transform Raman spectroscopy and 13C solid‐state nuclear magnetic resonance. First results indicate that the most important structural differences between both polymorphs occur in the mesogenic unit.
Thermal degradation of polymers of captodative substituted olefins
Authors: Tanaka Hitoshi , Hall Henry K.
Published: April 2003

Thermal degradations of the polymers of some captodative substituted olefins were studied by means of thermal gravimetry, infrared and electron paramagnetic resonance (EPR) spectroscopy, and evolved gas analysis. It was found that the initial degradation temperature of the homopolymers varies from 166 to 291°C and is correlated to the magnitude of the EPR coupling constant of the β‐hydrogen of the radicals derived from the corresponding captodative olefins. It was also found that poly(methyl α‐methoxyacrylate) depolymerizes to the monomer, while poly(α‐cycanovinyl acetate) eliminates mainly acetic acid to give a polyene.
Synthesis and structural study of an ABA block copolymer consisting of poly(ε‐benzyloxycarbonyl‐L‐lysine) as the a block and poly(ethylene oxide) as the B block
Authors: Cho Chong‐Su , Jo Byung‐Wook , Kwon Joong‐Kuen , Komoto Tadashi
Published: April 2003

ABA‐type block copolymers composed of poly(ε‐benzyloxycarbonyl‐L‐lysine) (PCLL) as the A component and poly(ethylene oxide) as the B component were synthesized by polymerization of ε‐benzyloxycarbonyl‐L‐lysine N‐carboxyanhydride initiated by primary amino groups located at both ends of the PEO chain. From circular dichroism measurements in solution, as well as from infrared spectra measurements in the solid state, it was found that the polypeptide block exists in the α‐helical conformation, as in PCLL homopolymer. The intensity of wide‐angle X‐ray diffraction patterns of the block copolymers depends on the PEO content and shows basically similar reflections as the PCLL homopolymer. The morphology examined by transmission electron microscopy and differential scanning calorimetry revealed microphase‐separated structure.
Polylactones, 29. Preferentially syndiotactic poly(β‐(R,S)‐butyrolactone) obtained by ring‐opening polymerization with triphenyltin methoxide or diphenyltin dimethoxide
Authors: Kricheldorf Hans R. , Lee Soo‐Ran
Published: April 2003

Triphenyltin methoxide (Ph3SnOMe) and diphenyltin dimethoxide (Ph2Sn(OMe)2)‐initiated polymerizations of β‐(R,S)‐butyrolactone were conducted in bulk at 50 and 75°C. The low catalytic reactivity of the initiator prevented lower temperatures. The stereosequences of the isolated poly(β‐(R,S)‐butyrolactones) were analyzed by 13C NMR spectroscopy and characterized by the ratio of isotactic and syndiotactic diads (i/s‐ratios down to 0,4/1,0 were found). With Ph3SnOMe relatively high molecular weights (ηinh = 0,3 dL/g, M̄w ≈ 25 000−30000) were obtained but the stereoselectivity of the polymers obtained with both Ph3SnOMe and Ph2Sn(OMe)2 is not higher than that with Bu3SnOMe (published previously). Selected poly(β‐(R,S)‐butyrolactone) samples were characterized by IR spectra, WAXS powder patterns and DSC measurements.
Copolymers with soft and hard segments based on 2,2‐dimethyltrimethylene carbonate and ε‐caprolactone
Authors: Gerhard‐Abozari Eva , Keul Helmut , Höcker Hartwig
Published: April 2003

Thermoplastic elastomers with ABA‐block structure, A representing the hard segment and B the soft segment, were prepared by ring‐opening polymerization from 2,2‐dimethyltrimethylene carbonate (DTC, 1) and ε‐caprolactone (ECL, 2) as monomers. Typical anionic initiators, viz. the dilithium salt of hydroxytelechelic poly(ethylene oxide) 200 (4) and of polytetrahydrofuran 1000 (5) and as an insertion initiator the bis(diethylaluminium) salt of triethylene glycol were used. The soft block is formed by a sequence of random (or tapered) structure comprising equimolar amounts of the two monomers and obtained by simultaneous polymerization of DTC and ECL. The hard blocks consist of highly crystalline poly(2,2‐dimethyltrimethylene carbonate) sequences. The thermal properties of the polymers depend on the sequence length, the content of heterodiads in the soft block and the thermal history of the samples. Copolymer films with short end blocks and high content of heterodiads show rubber‐elastic properties at normal conditions.
Soluble polystyrene derivatives of metal bis(3,4‐dicarboxybenzoyl)phthalocyaninates: Synthesis, thermal analysis, and sensitivity towards toxic gases
Authors: Zhou Rongnong , Tang Ligong , Geckeler Kurt E. , Göpel Wolfgang
Published: April 2003

Polystyrene‐bound metal [2,9 or 2,10 (or 2,16 or 2,17) bis(3,4‐dicarboxybenzoyl)]phthalocyaninates were synthesized by Friedel‐Crafts reaction of polystyrene with the corresponding metal phthalocyaninates. Co(II) and Cu(II) [2,9 or 2,10 (or 2,16 or 2,17) bis(3,4‐dicarboxybenzoyl)]‐phthalocyaninate (PS‐CodaPc and PS‐CudaPc) contained 0,13 mmol · g−1 (12,4 wt.‐%) and 0,13 mmol · g−1 (12,8 wt.‐%) of CodaPc and CudaPc, respectively. They were soluble in N,N'‐dimethylformamide, but only partially soluble in chloroform, tetrahydrofuran (THF), dimethyl sulfoxide, N‐methyl‐2‐pyrrolidone, and pyridine. The THF extracts contained 0,12 mmol · g−1 (11,4 wt.‐%) and 0,18 mmol − g−1 (17,2 wt.‐%) of PS‐CodaPc and PS‐CudaPc, respectively. The thermal stability of the polymers was studied using thermogravimetric and differential thermal analysis in nitrogen and synthetic air atmosphere. The contents of MdaPc(M: metal) in THF‐extracted polymers calculated from the data of residue in thermogravimetric analysis are 0,12 mmol · g−1 for PS‐CodaPc and 0,19 mmol · g−1 for PS‐CudaPc. In addition, the sensitive properties of the polymers towards toxic gases were also investigated by quartz microbalance transducers. The results show that the quartz microbalance sensors coated with both polymers were sensitive to NO2 and chlorinated hydrocarbons, i.e. chloroform and perchloroethylene. The sensitivity to NO2 was 6,53 · 10−7 m3 · mL−1 · s−1 for PS‐CodaPc and 1,90 · 10−6 m3 · mL−1 · s−1 for PS‐CudaPc, and that to chloroform and perchloroethylene was 2,33 · 10−8 and 4,60 · 10−8 m3 · mL−1 · s−1, respectively, for PS‐CodaPc and 4,79 · 10−8 and 9,51 · 10−7 m3 · mL−1 · s−1 for PS‐CudaPc.
Monomer sequence distributions in the copolymerization of ethylene and 1‐decene
Authors: Peña Begoña , Delgado Juan A. , Pérez Ernesto , Bello Antonio
Published: April 2003

Four ethylene‐1‐decene copolymers, covering a wide range of compositions, were analyzed in solution by means of 13C NMR spectroscopy. A detailed assignment of the signals to the different triad sequences was carried out. The experimental triad distributions were compared with calculations assuming Bernouillian and first‐order Markov statistics, finding a better agreement for the latter model. The triad distributions were also used for the determination of the reactivity ratios of the two comonomers.
Miscibility of an oligo(p‐phenylenevinylene) with polystyrene studied by solid‐state nuclear magnetic resonance
Authors: Nouwen Johan , Adriaensens Peter , Gelan Jan , Verreyt Gunther , Yang Zhou , Geise Herman J.
Published: April 2003

Molecular proximity of cis/trans mixtures of 2,5‐dimethoxy‐1,4‐bis[2‐(3,4,5‐trimethoxyphenyl)vinyl]benzene (MPV, 1) and polystyrene (PS) in mixtures of different MPV/PS weight ratios up to 60/40 is shown by 1H combined rotation and multiple pulse spectroscopy (CRAMPS) using 2D exchange experiments. The MPV/PS mixtures up to a weight ratio 60/40 are homogeneous, whereas the mixture with a weight ratio MPV/PS = 80/20 is heterogeneous. The comparison of the cross polarization/magic angle spinning (CP/MAS) 13C NMR spectra of pure MPV and of MPV mixed with PS shows significant linebroadening in case of intimate mixing, while the heterogeneous mixture shows some extra finestructure. The miscibility results were confirmed by proton spin‐locking relaxation time measurements (T1ρH) on the mixtures. On intimate mixing, T1ρH is averaged out and varies linearly as a function of the composition of the mixture. CRAMPS‐spectra and T1ρH measurements show that iodine‐doped MPV/PS mixtures (weight ratios 40/60 and 60/40) are heterogeneous. Furthermore, doping causes a slight proton chemical shift change and reduces the T1ρH‐values of those oligomer‐polymer systems.
TiCl4/MgH2‐supported Ziegler‐type catalyst system, 4. The influence of 14CO contact time and mole ratio Al(C2H5)3/Ti on concentration of active sites in ethylene homo‐ and copolymerization
Authors: Jaber Isam A. , Fink Gerhard
Published: April 2003

The effect of varying 14CO contact time upon the concentration of active centres C* in ethylene homopolymerization using the TiCl4/MgH2 · Al(C2H5)3 catalytic system shows that the polymer radioactivity, and hence C*, increase sharply in the first sixty minutes of 14CO contact with the polymerization centres. For contact times longer than one hour, the polymer radioactivity continues to increase, but very slowly. Studies on the effect of the mole ratio Al(C2H5)3/Ti on ethylene homopolymerization show that both the catalytic activity and C* increase sharply when increasing the mole ratio Al(C2H5)3/Ti in the range from 5 to 20. When increasing the mole ratio Al(C2H5)3/Ti above 50, C* tends to decrease very slightly. In ethylene/1‐hexene copolymerization a similar effect of the mole ratio Al(C2H5)3/Ti on the polymerization is observed. However, even though the catalytic activity in copolymerization is observed to be higher than in homopolymerization, at the same mole ratio Al(C2H5)3/Ti, yet C* in both cases is found to be more or less the same.
Copolymerization of styrene, maleic anhydride and acrylonitrile up to high conversion
Authors: Santos Regina De J. , Soares Bluma G. , Gomes Ailton S.
Published: April 2003

Terpolymers of styrene, maleic anhydride and acrylonitrile were synthesized by variation of the molar ratios of the three monomers at total monomer conversion up to 90 mol‐%. Polymerizations were performed with total initial monomer concentrations of 0,25 g/mL in benzene at 60°C with AIBN as initiator. The composition of the terpolymers was determined by elemental analysis. Although this ternary system comparises only one electron‐donor monomer and two electron‐acceptor monomers, maleic anhydride is the most reactive monomer and is incorporated in higher proportions than the other monomers.
Thermal and mechanical properties of poly(ether urethane) modified by copolyamide segments
Authors: Ahn Tae Oan , Choi Il Seok , Lee Sang Won , Jeong Han Mo
Published: April 2003

Thermoplastic polyurethane elastomers (TPUs) from diol‐terminated poly(tetramethylene glycol) (PTMG), 1,4‐butanediol (BD), and 4,4′‐methylenediphenyl diisocyanate (MDI) were modified by copolymerizing diamine‐terminated nylon‐6/6,6 copolyamide oligomer. In TPUs modified by the copolyamide segment, the hard segment showed decreased crystallinity and melting point depression as the content of copolyamide segment was increased, which is probably due to mixing and strong interaction between copolyamide and hard segments. As some of the hard segments were replaced by copolyamide segments, the crystallinity of PTMG segments increased. This suggests that the copolyamide‐PTMG segment interaction is weaker than the interaction between hard and PTMG segments. Tensile properties of TPUs are discussed based on the thermal properties.
Forced surface diffusion of polyelectrolytes
Authors: Noolandi Jaan
Published: April 2003

The controlled diffusion of polyelectrolytes across a surface is of interest for preparing ordered surface structures, studying molecule‐surface interactions (molecular friction), obtaining information about surfaces using standard molecular probes, separating large DNA fragments, and also for basic studies of the different modes of motion of polyelectrolytes along the surface. We suggest a simple scheme for studying forced surface diffusion of charged macromolecules across a surface under a conducting fluid. Some of the possible modes of motion are discussed.
Water‐soluble polymers with styrenesulfonate and maleic acid units in the backbone
Authors: Bortel Edgar , Kochanowski Andrzej , Witek Ewa
Published: April 2003

The radical copolymerization of maleic acid (MAc) with sodium p‐styrenesulfonate (sodium 4‐vinylbenzenesulfonate) (NaSS) in aqueous solution yielded copolymers containing both: carboxylic and sulfonic groups attached to the backbone. By changing initiator concentrations and temperatures, the weight‐average molecular weights, M̄w, were tailored in the range between 83 · 103 and 265 · 103. The corresponding intrinsic viscosities extended from 0,270 to 810 cm3/g, giving rise to the Mark‐Houwink equation: [η] = 7,65 · 10−6 · M0,924 solvent aqueous 0,1 M NaCl; (25°C). The highest degree of conversion at the conditions employed amounted to 83%. Based on the sulfur content found analytically, an equal share of both monomeric units was established. The structure of the copolymer poly[(maleic acid)‐co‐(sodium p‐styrenesulfonate)] obtained was elucidated by means of 13C NMR, 1H NMR and IR spectroscopy. After converting the sulfonate groups to their H+ ‐form through ion exchange, the copolymer was submitted to potentiometric 0,1 M NaOH titration yielding a dE/dV vs. α curve (with E electromotive force, V volume of titrant and α degree of neutralization), which deviates in shape from theoretical expectations. This deviation was attributed to high ionic strength within the polymeric coils.
Binary copolymerizations of styrene and conjugated diolefins in the presence of cyclopentadienyltitanium trichloride‐methylaluminoxane
Authors: Zambelli Adolfo , Proto Antonio , Longo Pasquale , Oliva Patrizia
Published: April 2003

Binary copolymerizations of styrene, isoprene, butadiene and 4‐methyl‐1,3‐pentadiene, in the presence of the catalyst cyclopentadienyltitanium trichloride‐methylaluminoxane (CpTiCl3‐MAO), are investigated. The reactivity ratios as well as the reactivities of the different monomers in homopolymerization are tentatively correlated to a possible polymerization mechanism. A qualitative explanation of the reactivity of different monomers in homo‐ and copolymerization is achieved by considering the nucleophilicity of the monomers and the electrophilicity of the active species. The latter is affected by the nature of the bond between the active Ti and the last unit of the growing chain end. The block copolymerization of ethylene with styrene is also tentatively explained by considering that the more the active species are electrophilic the less they should be selective toward monomers of different nucleophilicity.
Thermotropic elastomers with poly(oxy‐1,4‐butanediyl) units in the main chain
Authors: Pospiech Doris , Komber Hartmut , Voigt Dieter , Häußler Liane , Meyer Evelin , Schauer Gottfried , Jehnichen Dieter , Böhme Frank
Published: April 2003

The paper describes the synthesis of thermotropic elastomers from trimellitimide‐terminated poly(oxy‐1,4‐butanediyl) [synonyms: poly(tetramethylene ether glycol), PTMG; poly(tetrahydrofuran), poly(THF)] and acetoxy group‐terminated rigid blocks. Copolyester imides are formed by transesterification polycondensation in the melt. According to 13C NMR investigations, their chain sequence distribution is characterized by a block‐like structure in which the preformed rigid units are partially exchanged by transesterification reactions during the melt polycondensation. The degree of transesterification depends on the reaction time. The influence of the length of the flexible PTMG units and of the concentration of rigid units on the phase behaviour as well as on the thermal behaviour and the dynamic‐mechanical behaviour of the block copolymers is discussed with respect to aromatic model compounds.
Synthesis and properties of aromatic polyamides from 2,7‐triptycenediamine
Authors: Kasashima Yoshio , Kaneda Takuya , Saito Go , Akutsu Fumihiko , Naruchi Kiyoshi , Miura Masatoshi
Published: April 2003

Aromatic polyamides were synthesized by the low‐temperature solution polycondensation of 9,10‐dihydro‐9,10‐o‐benzeno‐1,5‐anthracenediamine (2,7‐triptycenediamine) with aromatic diacyl dichlorides. All the polycondensations proceeded in quantitative yields. The obained aromatic polyamides have high inherent viscosities (ca. 1,04–3,24 dL/g). They are soluble in various organic solvents such as 1‐methyl‐2‐pyrrolidone (NMP). The polyamides show high glass transition temperatures (Tg ≈ 337–370°C) and high decomposition temperatures (ca. 446–486°C at 5% weight loss). In particular, the polyamide prepared from the diamine and 4,4′‐sulfonyldibenzoyl dichloride not only was soluble in dimethyl sulfoxide, N,N‐dimethylformamide, hexamethylphosphoric triamide, NMP, N,N‐dimethylacetamide and pyridine, but also showed high Tg (370°C).
Polybutadiene‐poly(methyl methacrylate) core‐shell latexes studied by high‐resolution solid‐state 13C NMR and DSC: Influence of the surface coverage of the polybutadiene seed latex and the latex composition on the interphase formation
Authors: Nzudie Denis Tembou , Delmotte Luc , Riess Gérard
Published: April 2003

High‐resolution solid‐state 13C NMR and differential scanning calorimetry (DSC) were used to examine the effect of the surface coverage of the polybutadiene seed latex by the surfactant and the latex composition on the interphase of PBut‐PMMA core‐shell latexes. On the basis of the determination of the relaxation time (T1ρ(H)), glass transition temperature (Tg) and transition zone (ΔTg), information on the interphase was obtained, such as the fraction of the PMMA in the interphase and the interphase thickness. An optimum surface coverage of the PBut seed latex particles was found to lead to the largest amount of interphase.
Ultraviolet spectrophotometric studies of the reactivity of a water‐soluble polymer containing pendant 8‐hydroxyquinoline moieties with metal ions
Authors: Hamaya Takeo , Hiratani Kazuhisa , Ohashi Kosaburo
Published: April 2003

The water‐soluble polymer 4 containing pendant 8‐hydroxyquinoline (oxine) moieties was prepared and its reactivity with metal ions was studied by means of ultraviolet (UV) spectrophotometry. Polymer 4 was found to form complexes with metal ions in a mole ratio of 2 : 1 (oxine : metal), which is also obtained for the metal complexes of model compound 3 except for the Mg2+ complex. Polymer 4 hardly reacts with Mg2+, while model compound 3 forms a 1 : 1 mol/mol complex. The stability of the complexes of polymer 4 with metal ions was found to decrease in the following order: Cu2+ > Ni2+ > Zn2+ > Cd2+ > Hg2+ > Mg2+.
Synthesis and NMR characterization of a series of linear monodisperse poly(aryl ether ketone) and poly(aryl ether sulfone) oligomers
Authors: Finocchiaro Paolo , Montaudo Giorgio , Mertoli Patrizia , Samperi Filippo
Published: April 2003

New poly(aryl ether ketone) and poly(aryl ether sulfone) monodisperse model oligomers were synthesized in good yield via nucleophilic reactions. They were characterized by means of 1H and 13C NMR spectroscopy, and all chemical shifts were assigned to the corresponding nuclei. Both proton and carbon chemical shifts are very sensitive to the electronic environment generated by the O, CO and SO2 bridges, but in all oligomers, nuclei with similar electronic environments are very close to each other no matter what the sequence or the length of the oligomer is. Only quaternary carbons are more sensitive to the nature of the bridging groups, and therefore their chemical shifts can be of utility in sequencing the polymers.
Compatibilization and structure of poly(propylene)/nylon‐12 blends
Authors: Tang Tao , Li Hongyun , Huang Baotong
Published: April 2003

In this paper, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and wide‐angle X‐ray diffraction (WAXD) were used to study the structure and compatibilization of poly(propylene) (PP)/nylon‐12 (PA 12) blends. The compatibilization of maleated PP(PP‐MA) and graft copolymer (PP‐MA‐g‐PEO) of PP‐MA and poly(ethylene oxide) (PEO) in PP/PA 12 blends was observed from the morphology of the fracture surface of PP/PA12 blends. The compatibilization mechanism was investigated. The DSC results showed that there was nucleation between PP and PA12. This was attributed to the unusual epitaxial relationship. The effect of PA12 on the crystalline structure of PP was studied by means of WAXD.
Polymères porteurs de dérivés du glycérol, 10. Fixation de l'acide naphtyl‐1 acétique sur le poly(acide méthacrylique)
Authors: Soutif Jean‐Claude , Karkab Said , Brosse Jean‐Claude
Published: April 2003

Glycidyl (2,3‐epoxypropyl) esters are convenient reagents for the fixation of carboxylic acid moieties on polymeric support of the polyacid type. This way of synthesis was applied to 1‐naphthylacetic acid on poly(methacrylic acid). Esterification of 1‐naphthylacetyl chloride by glycidol (2,3‐epoxy‐1‐propanol) and addition of 1‐naphthylacetic acid on epichlorohydrin (1‐chloro‐2,3‐epoxypropane) with subsequent reformation of the oxirane ring have been used for the synthesis of the glycidyl ester but the reaction of the potassium salt of the acid with epichlorohydrin leads to a better yield. Addition of 1‐naphthylacetic acid on glycidyl acetate was studied in N,N‐dimethylformamide (DMF) and acetonitrile. The best results were obtained in DMF. The reaction is of first order with respect of epoxide, but 2nd order applies when the solvent is acetonitrile. The same reaction conditions as for glycidyl acetate were used for the chemical modification of poly(methacrylic acid) with glycidyl 1‐naphthylacetate except that methanol was used as the solvent.
Studies on the behavior of photodegradation of poly(cyclohexylmethylsilane)
Authors: Chen Deben , Hu Huiping
Published: April 2003

The fluorescence spectra of poly(cyclohexylmethylsilaane) (PCHMS) solutions or films before and after ultraviolet irradiation in air were studied. The experimental results showed that the positions of the fluoresence peaks shift to shorter wavelength and the fluorescence intensities decrease gradually with increasing UV irradiation time. The results of UV spectra, GPC and ESCA, and IR spectra of PCHMS solutions or films upon UV exposure in air indicate that these phenomena are in accordance with a combined process of photodegradation and photooxidation, which lead to a decrease of the molecular weights and formation of siloxane structures in the polysilane main chains.
Kinetices of polymerization of 1‐octene with the catalyst system VOCl3‐AlEt3 (or AlEt2Br)
Authors: Kothandaraman Harimurthi , Devi Muthusamy Saroja
Published: April 2003

Kinetic studies of the polymerization of 1‐octene with the Ziegler‐Natta catalyst systems VOCl3—AlEt3 (I) and VOCl3—AlEt2Br (II) are reported. The effect of the various parameters such as the Al/V ratio, catalyst and monomer concentrations, reaction time, aging time and temperature on rate of reaction and molecular weight of polymer were studied. Each of these parameters has a profound effect on the polymer yield and the rate of the reaction for both systems. The rate of polymerization increases linearly with increasing temperature, catalyst and monomer concentrations. The reaction is first order with respect to both the monomer and the catalyst concentration in the two catalyst systems studied. From the Arrhenius plot the overall activation energy of polymerization for the two systems was found to be 51,2 and 43,5 kJ/mol, respectively. The mechanism of polymerization is discussed on the basis of the dependence of the polymerization rate on the alkylaluminium concentration.
Quantitative aspects of charge transfer in polyaniline during its electrodeposition and electrochemical degradation
Authors: Orata Duke , Matheka Anderson , Munge Bernard
Published: April 2003

The results presented in this paper reveal that the electrochemical degradation of polyaniline is strongly dependent on the potential window. Substantial agreement is observed between calculated and experimentally obtained values for the electrochemical parameters of films, i.e. peak current and charge. These results also reveal that the efficiency of the cyclic redox process is well below 100%.
UV/VIS‐spektroskopischer Nachweis einer selektiven Komplexbildung zwischen WOCl4 und trimethylaluminium. Ein weg zur Charakterisierung von methylaluminoxanen
Authors: Thorn‐Csányi Emma , Dehmel Jörg , Halle Olaf , Sciborski Winfried
Published: April 2003

The kinetic analysis of the reaction between WOCl4 and trimethylaluminium (TMA) shows that TMA forms a 2 : 1 mol/mol‐complex with WOCl4 before it acts as an alkylating agent. The reaction steps can be observed separately because rate constants kcomplex formation ≫ kalkylation and ultraviolet/visible (UV/VIS) absorption coefficients ϵcomplex ≠ ϵWOCl4. The rapid change of the WOCl4‐UV/VIS‐spectrum is typical for TMA and cannot be observed with methylaluminoxane (MAO) or with dimethylaluminium chloride. Due to the selective complex formation it is possible to determine the exact content of “free” TMA in MAO.
Study of polyampholyte hydrogels and interpenetrating polyelectrolyte networks based on 4‐(but‐3‐en‐1‐ynyl)‐1‐methylpiperidin‐4‐ol
Authors: Kudaibergenov Sarkyt E. , Nurgalieva Dametken E. , Bekturov Esen A. , Shaikhutdinov Erengaip M. , Nurkeeva Zauresh S. , Sigitov Vladimir B.
Published: April 2003

Polyampholyte hydrogels and interpenetrating polyelectrolyte networks (IPPN) based on 4‐(but‐3‐en‐1‐ynyl)‐1‐methylpiperidin‐4‐ol (1) have been synthesized by γ‐irradiation polymerization. The influence of the pH and ionic strength of the solution on the degree of swelling ϕ for both polyampholyte hydrogels and IPPN has been studied. The shrinking and swelling behaviour of crosslinked samples was explained by the formation or destruction of intra‐ and interpoly‐electrolyte complexes.
Synthesis and characterization of new siloxane‐modified addition polyimides
Authors: Laurienzo Paola , Malinconico Mario , Perenze Nicoletta , Segre Anna Laura
Published: April 2003

A new series of polyimides was synthesized by addition polymerization of 4,4′‐(bismaleimido)‐diphenylmethane, 1,4‐piperazine and an amino‐terminated polydimethylsiloxane. The synthesis was carried out in m‐cresol solution following a two‐step procedure. Copolymers containing 15 and 20 wt.‐% of the polydimethylsiloxane elastomer were prepared, together with the unmodified base copolymer. Infrared spectroscopy, 13C and 1H NMR, thermal and thermogravimetric analyses were used to characterize the copolymers. The DSC curves of all the samples showed an exotherm in the temperature range 230–280°C, attributable to curing and addition reactions involving the chain‐end groups. Different glass transition temperatures (Tg) were observed, depending on the elastomer content. Thermogravimetric analysis indicated that no significant changes occur in the thermal stability of rubber‐modified copolymers.
Nucleation of particles in seeded emulsion polymerization of vinyl acetate with poly(vinyl alcohol) as emulsifier
Authors: Lepizzera Stephane M. , Hamielec Archie E.
Published: April 2003

Seeded emulsion polymerizations of vinyl acetate with and without poly(vinyl alcohol) were carried out in a batch reactor. Two types of poly(vinyl alcohol) (different molecular weights but the same degree of hydrolysis) have been investigated. In the absence of poly(vinyl alcohol) no new nucleation was observed, while in its presence new particles were formed, giving a bimodal particle size distribution. The number of new particles was greater with the higher‐molecular‐weight poly(vinyl alcohol). Compared with emulsifier‐free seeded emulsion polymerization, the reaction rate increased when the higher‐molecular‐weight poly(vinyl alcohol) was used. However, the polymerization rate decreased when the lower‐molecular‐weight poly(vinyl alcohol) was applied. It was also shown that for seeded emulsion polymerization of vinyl acetate in the absence of poly(vinyl alcohol), the kinetics follows Smith‐Ewart case III theory. These observations are discussed and a theory is proposed to explain the effect of macromolecular emulsifier on the nucleation of particles in seeded emulsion polymerization. This theory involves nucleation of new particles via precipitation of “copolymer” poly(vinyl alcohol)‐poly(vinyl acetate) radicals in the water phase.
Synthesis and characterization of poly(1‐benzoylthiosemicarbazide) and poly(1,3,4‐thiadiazole amine) from 2‐(p‐aminophenyl)‐1,3,4‐oxadiazoline‐5‐thione via ring‐opening process
Authors: Saegusa Yasuo , Ozeki Yasuhiro , Harada Shigeo , Nakamura Shigeo
Published: April 2003

A novel thermally stable and semiconducting polyheterocycle, poly(1,3,4‐thiadiazole amine), was synthesized from 2‐(p‐aminophenyl)‐1,3,4‐oxadiazoline‐5‐thione via ring‐opening. The polymer is a new class of ordered alternating copoly(aniline) containing 1,3,4‐thiadiazole heterocyclic units. An investigation of the reaction of 2‐phenyl‐1,3,4‐oxadiazoline‐5‐thione with aniline was conducted as a model reaction for the polymerization, and poly(phosphoric acid) (PPA) and phosphorus pentoxide/methanesulfonic acid (PPMA) were found to be favorable both as condensing agent and solvent for the formation of 2‐anilino‐5‐phenyl‐1,3,4‐thiadiazole as a model compound. The polymerization was carried out both by two‐step procedure that included ring‐opening self‐polyaddition giving poly(1‐benzoylthiosemicarbazide), followed by cyclodehydration to poly(1,3,4‐thiadiazole amine), and by a one‐step procedure including cyclodehydration in situ. The poly(1‐benzoylthiosemicarbazide) which was formed in the first step in m‐cresol had reduced viscosities up to 0,42 dL·g−1, and it was converted to poly(1,3,4‐thiadiazole amine) by treating in PPA or PPMA. Poly(1,3,4‐thiadiazole amine) having reduced viscosities up to 0,25 dL·g−1 was also synthesized by the direct one‐step polymerization in PPA or PPMA. The polymer is highly thermally stable and exhibited no weight loss up to 350°C under nitrogen. Its electric conductivity was less than 10−10 S·cm−1 at ambient temperature, but markedly increased to 2,9·10−7 S·cm−1 upon doping with iodine.
Preparation and properties of copolyamides‐6,6F and copolyamides‐4,8F containing oligo(tetrafluoroethylene)segments
Authors: Steinhauser Norbert , Mülhaupt Rolf
Published: April 2003

Two families of copolyamides‐6,6F and copolyamides‐4,8F containing various amounts of bis‐ and tris(tetrafluoroethylene) segments were prepared to study the influence of such fluorine‐containing segments on bulk and surface properties. In a solution polycondensation process telechelic aliphatic diamines, obtained by reacting dimethyl α,ω‐dicarboxylatooligo(tetrafluoroethylene)s with excess diamines, e. g., tetramethylenediamine and hexamethylenediamine, were polymerized with activated bis(4‐nitrophenyl) adipate and bis(4‐nitrophenyl) suberate. In the presence of various stoichiometric amounts of the aliphatic diamines, the fluorine content varied between 0 and 39 wt.‐% and the inherent viscosities between 0,27 and 1,02 dL/g. As content and segment length of the oligo(tetrafluoroethylene) segments increased, the polymer solubilities in organic solvents and the contact angles to water increased, whereas melting temperatures, crystallinities (as measured by means of differential scanning calorimetry and wide‐angle X‐ray scattering (WAXS)) and thermal stabilities (as determined by means of thermogravimetric analysis of the weight loss encountered at elevated temperatures) were reduced markedly. The WAXS measurements reflected changes of crystal structures with increasing fluorine content.
Preparation and characterization of silica‐ and magnesia‐supported poly(3‐aminopropylsiloxane)‐platinum complexes and their catalytic activity in the oxidation of cyclohexanol and cyclopentanol with molecular oxygen
Authors: Jia Cheng‐Guo , Liang Fu‐Yan , Tang Liang‐Jie , Huang Mei‐Yu , Jiang Ying‐Yan
Published: April 2003

We have prepared silica‐ and magnesia‐supported poly(3‐aminopropylsiloxane)‐platinum complexes (abbreviated as SiO2‐PAPSPt and MgO‐PAPSPt, respectively) in which mixed valent platinum is coordinated by amino groups and aggregated to a certain extent. MgO‐PAPSPt contains low‐valent, very small and almost homogeneously dispersed platinum aggregates (diameter ca. 20 Å) and is highly active, stable and recyclable in the oxidation of cyclohexanol and cyclopentanol under atmospheric pressure of oxygen. In contrast, large platinum aggregates (ca. 30–100 Å, 60 Å on an average) are found in SiO2‐PAPSPt, and almost no zero‐valent platinum is present. We assume this is the reason for its very low activity in oxidations under the same conditions.
Metathesis polymerization of endo‐5‐ and exo‐5‐chloromethylbicyclo[2.2.1]hept‐2‐ene and of 5,5‐bis(chloromethyl)bicyclo[2.2.1]hept‐2‐ene; microstructure of the polymers
Authors: Ivin Kenneth J. , Lam Luk‐Mui , Rooney John J.
Published: April 2003

The three title monomers were polymerized using a variety of Ru‐, Ir‐, Mo‐, W‐ and Re‐based metathesis catalyst systems to yield polymers having a wide range of cis double bond contents in each case. The 13C NMR spectra of the polymers were interpreted in terms of cis/trans, head/tail and m/r microstructures. No head‐tail bias was observed in any of the polymers.
Assignment of the 1H and 13C NMR spectra and stereochemical analysis of radical‐initiated poly(1‐naphthylmethyl acrylate) and poly[2‐(1‐naphthyl)ethyl acrylate]
Authors: Spyros Apostolos , Dais Photis , Heatley Frank
Published: April 2003

Resonances in the 1H and 13C NMR spectra of free‐radical polymerised poly(1‐naphthylmethyl acrylate) (PNMA) and poly[2‐(1‐naphthyl)ethyl acrylate] (PNEA) have been assigned using two‐dimensional techniques. The stereosequence distribution in both polymers obeyed Bernoullian statistics with probabilities of an isotactic diad of 0,43 in PNMA and 0,39 in PNEA.
Synthesis of α,ω‐dialkenyl isotactic poly(propylene) using bis(4‐methyl‐3‐pentenyl)zinc as a chain transfer reagent
Authors: Kurosawa Hiroki , Shiono Takeshi , Soga Kazuo
Published: April 2003

Propene polymerization was conducted with the catalyst system composed of TiCl3 and bis(4‐methyl‐3‐pentenyl)zinc (BMPZ) in the absence or presence of Al(C2H5)2Cl. The catalyst system with or without Al(C2H5)2Cl gave isotactic poly(propylene) (PP) with a lower molecular weight as compared to the TiCl3/Al(C2H5)2Cl system. From the 1H and 13C NMR analyses, it was found that the polymer produced with the TiCl3/BMPZ catalyst possesses a 2,6‐dimethyl‐5‐heptenyl group and a Zn‐PP bond at the initial and terminal ends, respectively. The Zn‐terminated end was then converted to a vinyl group by coupling with allyl bromide in the presence of N‐methylimidazole to obtain isotactic PP having CC double bonds at both chain ends.