bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Properties of Poly(ketone‐co‐alcohol) Materials: Shape Memory Thermoplastic Elastomers by Control of the Glass Transition Process
Authors: Pérez‐Foullerat David , Hild Sabine , Mücke Angela , Rieger Bernhard
Published: February 2004

Summary: The well‐controlled reduction of polyketone carbonyl functional group was performed without chain degradation by using NaBH4 in tetrahydrofuran (THF)/MeOH solvent mixtures. Three different families of flexible polyketones (alternating propene/CO “PCO”, hex‐1‐ene/CO “HxCO” copolymers, and “pulse feed” alternating olefin/CO terpolymers from ethene and propene “EPCO”) were investigated to achieve either a partial reduction, leading to poly(ketone‐co‐alcohol)s of corresponding composition, or a complete conversion into polyalcohols. Increasing the ratio of [OH]/[CO] functions allows continuous change of the Tg of the resulting polymers from below room temperature to about 75 °C. Properties of the synthesized materials, like thermal decomposition, glass transition temperature, surface tension, and mechanical performance, are described depending on the degree of reduction. Thermoplastic elastomers with an interesting “shape memory” effect result from the partially reduced, elastic EPCO terpolymers.

Stress‐strain curves for ethylene‐propylene/CO copolymers reduced to different extents.

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Stress‐strain curves for ethylene‐propylene/CO copolymers reduced to different extents.
Syndiospecific Polymerization of Styrene with Aryl Substituted Indenyl Halfsandwich Titanocenes
Authors: Stojković Olivera , Kaminsky Walter
Published: February 2004

Summary: A series of 1‐ and 2‐aryl substituted indenyl titanium trichlorides (ArIndTiCl3, Ar = Ph, α‐Naph, β‐Naph) were synthesized and tested as catalyst precursors for the syndiospecific polymerization of styrene with methylaluminoxane (MAO) as a cocatalyst. The polymerization characteristics at varying Al:Ti ratios and the kinetic behavior of these systems were investigated at 30 and 50 °C. The optimal Al:Ti ratio for these compounds lies in the range of 750–1500 at 30 °C, while the optimum shifts to higher values of about 2000–5000 at 50 °C. The activity of the investigated catalysts decreases in the order 2‐PhInd > Ind > Cp > 1‐(β‐Naph)Ind > 1‐PhInd > 2‐(β‐Naph)Ind > 2‐(α‐Naph)Ind > 1‐(α‐Naph)Ind with an activity up to 6700 kg sPS/[(mol Ti) · h] for 2‐PhIndTiCl3/MAO as the most active catalyst. Compared with CpTiCl3/MAO, the indenyl substituted compounds show, as catalysts, increased long‐term stability, which was determined by variation of the polymerization time. Especially 2‐PhIndTiCl3, 1‐(β‐Naph)IndTiCl3 and 2‐(β‐Naph)IndTiCl3 show a good performance. Syndiotactic polystyrenes with extremely high molar masses up to 1.3 × 106 g/mol can be obtained by the catalytic system 2‐(β‐Naph)IndTiCl3/MAO.

Dependence of the polymerization rate on polymerization time. Polymerization conditions: Tp = 30 °C, V = 150 ml, c(styrene) = 1.04 M, Al:Ti = 1500, m(MAO) = 0.145 g, solvent = toluene.

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Dependence of the polymerization rate on polymerization time. Polymerization conditions: Tp = 30 °C, V = 150 ml, c(styrene) = 1.04 M, Al:Ti = 1500, m(MAO) = 0.145 g, solvent = toluene.
Ethene Copolymerization with Trialkylsilyl Protected Polar Norbornene Derivates
Authors: Wendt Ralf Alexander , Angermund Klaus , Jensen Vidar , Thiel Walter , Fink Gerhard
Published: February 2004

Summary: The influence of the protecting group of polar norbornene derivatives and the structure of homogenous metallocene/MAO catalyst systems on the activity and the incorporation rates during ethene copolymerization reactions were studied. By varying the structure of the protecting group a relationship between the catalyst activity and the steric demand of the protecting group could be established. For the catalyst systems tested analogous relationships between the bulkiness of the protecting groups and the polymerization activity were found. Kinetic investigations point to a reversible deactivation reaction, during which a bond between the oxygen atom of the polar norbornene derivative and the center of the active catalyst is formed, competing with the olefin coordination and the subsequent insertion. The degree of polymerization deactivation can be qualitatively judged based on a correlation between calculated structural parameters of the trialkylsilyl protected norbornene derivatives and the experimentally determined polymerization activity.

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Stereoblock Isotactic‐Hemiisotactic Poly(propylene)s and Ethylene/Propylene Copolymers Obtained with ansa‐Cyclopenta[1,2‐b;4,3‐b′]dithiophene Catalysts
Authors: Ewen John A. , Jones Robert L. , Elder Michael J. , Camurati Isabella , Pritzkow Hans
Published: February 2004

Summary: Stereoblock, isotactic‐hemiisotactic poly(propylene) is produced with C1‐symmetric Me2C(η5‐3‐(2‐adamantyl)‐C5H3)(η5‐C9H4S2)ZrCl2 (1). Ethylene/propylene copolymerization data with the Cs‐symmetric Me2C(η5‐C5H4)(η5‐C9H4S2)ZrCl2 (2) metallocene reveals that it is highly propylene‐specific and that it produces more random ethylene/propylene copolymers than its fluorenyl analog.

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Supporting Effects of Methylaluminoxane on the Living Polymerization of Propylene with a Chelating (Diamide)dimethyltitanium Complex
Authors: Hagimoto Hitoshi , Shiono Takeshi , Ikeda Tomiki
Published: February 2004

Summary: Modified methylaluminoxane (MMAO), from which free AlMe3 and Al(iBu)3 were reduced to ca. 0.1 mol‐%, was supported on metal oxides, such as anhydrous silica gel, alumina, or magnesia; the metal oxide‐supported MMAO prepared were used as cocatalysts for propylene polymerization combined with a chelating (diamide)dimethyltitanium complex. The systems conducted living polymerization of propylene at 0 °C regardless of the support for MMAO. The propagation rate constants (kp) of these systems and the molecular weight distribution ($\overline M _{\rm w} {\rm /}\overline M _{\rm n}$) of the produced polymer depended on the metal oxide employed. The XPS analysis of the supported MMAOs suggested that the kp value increased with the Lewis acidity of MMAO on the support and the broadening $\overline M _{\rm w} {\rm /}\overline M _{\rm n}$ was ascribed to the distribution of kp caused by the heterogeneity of the supported cocatalyst.

Plots of \overline M _{\rm n} and \overline M _{\rm w} {\rm /}\overline M _{\rm n} against polymerization time in propylene polymerization with [ArN(CH2)3NAr]TiMe2: MMAO/SiO2 system, \overline M _{\rm n} (•), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (○); MMAO/Al2O3 system, \overline M _{\rm n} (▴), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (▵); MMAO/MgO system, \overline M _{\rm n} (▪), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (□); corresponding homogeneous system, \overline M _{\rm n} (▾), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (▿).

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Plots of \overline M _{\rm n} and \overline M _{\rm w} {\rm /}\overline M _{\rm n} against polymerization time in propylene polymerization with [ArN(CH2)3NAr]TiMe2: MMAO/SiO2 system, \overline M _{\rm n} (•), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (○); MMAO/Al2O3 system, \overline M _{\rm n} (▴), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (▵); MMAO/MgO system, \overline M _{\rm n} (▪), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (□); corresponding homogeneous system, \overline M _{\rm n} (▾), \overline M _{\rm w} {\rm /}\overline M _{\rm n} (▿).
Preparation and Characterization of Novel Temperature Sensitive Poly(N‐isopropylacrylamide‐co‐acryloyl beta‐cyclodextrin) Hydrogels with Fast Shrinking Kinetics
Authors: Zhang Jian‐Tao , Huang Shi‐Wen , Zhuo Ren‐Xi
Published: February 2004

Summary: Novel temperature sensitive poly(N‐isopropylacrylamide‐co‐acryloyl beta‐cyclodextrin) (P(NIPA‐co‐A‐CD)) hydrogels with fast shrinking rates were prepared by radical polymerization of NIPA, A‐CD and crosslinker in a mixture of water/1,4‐dioxane as solvent. Because the mixed solvent was a poor solvent for the copolymers, phase separation occurred during the polymerization, which resulted in a heterogeneous, porous structure of the hydrogels. In contrast to the normal PNIPA hydrogel and the homo P(NIPA‐co‐A‐CD) gel prepared in water, the P(NIPA‐co‐A‐CD) hydrogels synthesized in water/1,4‐dioxane as solvent exhibited higher swelling ratios at the temperature below the lower critical solution temperature (LCST) and shrunk rapidly to equilibrium within shorter time when the temperature was increased above LCST. Increasing the acryloyl beta‐cyclodextrin content in the gels led to a slight decrease of the swelling ratio at lower temperature and had no marked influence on the shrinking kinetics. The gels prepared in water/1,4‐dioxane, at different v/v ratios of 1.0/0.2, 0.8/0.4 and 0.6/0.6, showed similar properties.

SEM photos of the heterogeneous P(NIPA‐co‐A‐CD) hydrogel prepared in water/1,4‐dioxane.

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SEM photos of the heterogeneous P(NIPA‐co‐A‐CD) hydrogel prepared in water/1,4‐dioxane.
New Zinc Dicarboxylate Catalysts for the CO2/Propylene Oxide Copolymerization Reaction: Activity Enhancement Through Zn(II)‐Ethylsulfinate Initiating Groups
Authors: Eberhardt Robert , Allmendinger Markus , Zintl Manuela , Troll Carsten , Luinstra Gerrit A. , Rieger Bernhard
Published: February 2004

Summary: A series of zinc dicarboxylates were synthesized by the reaction of diethylzinc with dicarboxylic acids. Zinc monocarboxylate monoalkyl intermediates were obtained by using a defined excess of diethylzinc over dicarboxylic acid. A subsequent insertion reaction of SO2 into these zinc alkyl bonds resulted in a defined number of Zn‐ethylsulfinate groups, which act as active centers for the copolymerization reaction of CO2 and propylene oxide. Corresponding ethylsulfinic acid ester end groups were detected in the poly(propylene carbonate) (PPC) products. The polymerization activity depended strongly on the number of sulfinate groups incorporated and has been significantly increased compared to conventional zinc dicarboxylates. The obtained PPCs have molecular weights ($\overline M _{\rm w}$) exceeding 80 000 g · mol−1 and polydispersities in the range of 2.3 to 3.3.

Formation of poly(propylene carbonate).

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Formation of poly(propylene carbonate).
Saccharide Polymers, 5
Authors: Glümer Anke , Skeries Bernhard David , Buchholz Klaus
Published: February 2004

Summary: New “saccharide polymers” were synthesized via free radical polymerization. The saccharide compounds in copolymerisation reactions were 2,4,6‐tri‐O‐acetyl‐3‐deoxy‐D‐erythro‐hex‐2‐enono‐1,5‐lactone (1), (Ac‐GEL 1) and 2,4,6‐tri‐O‐benzoyl‐3‐deoxy‐D‐erythro‐hex‐2‐enono‐1,5‐lactone (2), (Bz‐GEL 2). These sugar monomers are easily obtained with high yield in a one step reaction from glucono‐δ‐lactone. They have a pyranoid structure containing an endocyclic double bond and they are electron acceptor compounds. Copolymerization reactions were carried out in solution and in substance. Copolymers with different sugar contents and low as well as high molecular weights were obtained. The structures and the compositions of the soluble saccharide polymers were established by elemental analysis, polarimetry, FTIR spectroscopy, 1H and 13C NMR spectroscopy. Some characteristic properties, e.g., molecular weight, optical rotation and copolymerization parameters are reported.

Schematic conversion of glucono‐δ‐lactone to saccharide monomers.

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Schematic conversion of glucono‐δ‐lactone to saccharide monomers.
Response of Polyelectrolyte Complexes to Subsequent Addition of Sodium Chloride: Time‐Dependent Static Light Scattering Studies
Authors: Dautzenberg Herbert , Rother Gudrun
Published: February 2004

Summary: The applications of polyelectrolyte complexes range from large‐scale industrial products to special uses in biotechnology and medicine, yet one significant problem is their instability against changes in their environmental conditions, particularly the addition of salts. This concerns the colloidal stability as well as the stability of ionic bindings. Previous work on the effect of sodium chloride revealed that not only additional aggregation, but also complete dissolution may occur, depending on the nature of the polyelectrolyte components used. In these studies, the systems required up to one hour to become stable. Multi‐angle static light scattering was used to investigate the processes taking place after the addition of NaCl to polyelectrolyte complexes (PEC) formed in pure water. PECs were prepared with polymethacrylate as polyanion and poly(diallyldimethylammonium chloride) and a copolymer of this polycation with 53 mol‐% of acrylamide. These systems were chosen because of their interesting behavior: secondary aggregation, swelling, and dissolution at a critical salt concentration. The time‐dependence of these effects was studied in detail by static light scattering.

Aggregation and swelling demonstrated by changes in particle mass, radius, and structure density of the PEC.

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Aggregation and swelling demonstrated by changes in particle mass, radius, and structure density of the PEC.
Effect of Additional Hydroxyl Functionalities on the Hydrolytic Stability of Oligoesters
Authors: Soucek Mark D. , Johnson Aaron H. , Meemken Leon E.
Published: February 2004

Summary: The addition of a trifunctional polyol (trimethylolpropane) to oligoesters comprised of hexahydrophthalic anhydride, cyclohexane‐1,4‐dicarboxylic acid, cyclohexane‐1,3‐dicarboxylic acid, neopentyl glycol, and cyclohexane‐1,4‐dimethanol was investigated via an accelerated hydrolysis environment. The oligoesters were dissolved in an acetone/water solution, and the hydrolysis was evaluated by monitoring carboxylic acid formation and by measurement of the molecular weight shift by size exclusion chromatography. Aliquots of the oligoester solution were evaluated intermittently over a 36‐week period. Both the initial rate and the overall rates of hydrolysis were reported as hydrolysis velocities. The influence of hydroxyl concentration is apparent in the initial velocity of hydrolysis. After the induction period, steric effects appear to be the controlling factor for the retardation of main chain scission.

A comparison of the initial and final rates of hydrolysis as a function of oligoester composition.

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A comparison of the initial and final rates of hydrolysis as a function of oligoester composition.
Multiple Melting Behavior of Poly(thiodiethylene terephthalate): Further Investigations by Means of X‐ray and Thermal Techniques
Authors: Fichera Anna Maria , Finelli Lara , Gazzano Massimo , Lotti Nadia , Munari Andrea
Published: February 2004

Summary: The complex multiple melting behavior of poly(thiodiethylene terephthalate) (PSDET) was investigated by means of differential scanning calorimetry, X‐ray diffraction and hot‐stage optical microscopy. The phenomenon was ascribed to the existence of two different crystal structures (α and β), each of them being able to melt and recrystallize under the experimental conditions adopted. Linear and nonlinear treatments were applied in order to estimate the equilibrium melting temperature for α PSDET, by using the corrected values of Tm. The nonlinear estimation led to a higher value by about 25 °C. Isothermal crystallization kinetics of each crystalline form were analyzed according to Avrami's treatment. In both cases, values of Avrami's exponent, n, close to 3 were obtained, in agreement with a crystallization process originating from predeterminated nuclei and characterized by three dimensional spherulitic growth. The rate of crystallization of each crystalline structure was found to become lower as the crystallization temperature is increased, as usual at low undercooling, where the crystallization process is controlled by nucleation.

XRD patterns of PSDET samples isothermally crystallized at the indicated Tcs.

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XRD patterns of PSDET samples isothermally crystallized at the indicated Tcs.
Direct Observation of Poly(propylene)‐block‐Poly(ethylene‐co‐propylene) Molecules by Atomic Force Microscopy
Authors: Prokhorov Valery V. , Nitta Koh‐hei , Terano Minoru
Published: February 2004

Summary: Atomic force microscopy (AFM) has been applied to get molecular images of diblock poly(propylene)‐block‐poly(ethylene‐co‐propylene) copolymers deposited on mica from diluted solutions at elevated temperatures. Both isolated molecules and their small aggregates have been visualized as compact particles of various sizes with outspreading poly(ethylene‐co‐propylene) chains. On the base of the height, volume and morphological analysis AFM images were divided into three groups. In the first group the compact particles are suggested to be small regular‐shaped crystallites formed by a few poly(propylene) blocks. Some isolated particles of this group were connected with single copolymer chains. In the second group the compact particles have larger dimensions and irregular or round shapes implying unordered packing of constituents. The third group were represented by isolated poly(ethylene‐co‐propylene) coils. The two‐dimensional expansion of coils on mica both isolated and included in aggregates exceeds several times their dimensions in a solution. The probable mechanism of such an expansion is proposed relying on the existence of van‐der‐Waals surface force field of a sufficient strength in the vicinity of the crystal surface.

Enlarged AFM height images of block‐copolymer aggregates of group A with small compact particles of regular shapes (frames a, b, c) and group B (frame d) with a large globular compact particle.

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Enlarged AFM height images of block‐copolymer aggregates of group A with small compact particles of regular shapes (frames a, b, c) and group B (frame d) with a large globular compact particle.
Metal‐ and Metalloid‐Containing Macromolecules Symposium
Authors: Abd‐El‐Aziz A. S. , Zeldin M.
Published: February 2004

Conference Report: This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de.
Cover Picture: Macromol. Chem. Phys. 1/2004
Authors: Eberhardt Robert , Allmendinger Markus , Zintl Manuela , Troll Carsten , Luinstra Gerrit A. , Rieger Bernhard
Published: February 2004

Cover: The cover page shows the formation of polycarbonate formation on solid Zn‐gluterate.

Further details can be found in the Full Paper by R. Eberhardt, M. Allmendinger, M. Zintl, C. Troll, G. A. Luinstra, and B. Rieger* on page 42.
Cover Picture: Macromol. Chem. Phys. 2/2004
Authors: Bolze Joerg , Ballauff Matthias , Rische Thorsten , Rudhardt Daniel , Meixner Jürgen
Published: February 2004

Cover: The cover shows small angle X‐ray scattering data of semicrystalline PUR latex particles. A data decomposition procedure yields the scattering contribution due to the lamellar structure.

Further details can be found in the Full Paper by J. Bolze, M. Ballauff,* T. Rische, D. Rudhardt, and J. Meixner on page 165.
Cover Picture: Macromol. Chem. Phys. 3/2004
Authors: Grassi Alfonso , Guerra Gaetano , Longo Pasquale , Oliva Leone , Pellecchia Claudio
Published: February 2004

Cover: The picture on the cover shows the copolymerization studies on deuterated propenes published by A. Zambelli, M. G. Giongo and G. Natta (Makromol. Chem. 1968, 112, 183). These studies allowed the elucidation of the cis mechanism of addition to the double bond, for the propene polymerization to syndiotactic polymers.

This special issue is dedicated to Prof. Adolfo Zambelli on the occasion of his 70th birthday.
Chemical Modification of Terephthalate Polyesters by Reaction with Bis(hydroxyethyl ether) of Bisphenol A
Authors: Berti Corrado , Colonna Martino , Fiorini Maurizio , Lorenzetti Cesare , Marchese Paola
Published: February 2004

Summary: Copolyesters of terephthalic acid with bis(hydroxyethyl ether) of bisphenol A (BHEEB) in different molar ratios have been synthesized by reactive blending from terephthalate polyesters and by melt polycondensation from the monomers. By this way, bisphenol A groups were inserted in the polyester chains with the aim to obtain polyesters with improved mechanical properties. The insertion of the BHEEB into the polyester backbone is quantitative and does not give rise to side reactions. These copolyesters can be obtained by the chemical recycling of commercial polymers; indeed BHEEB can be synthesized by chemical recycling of bisphenol A polycarbonate and may be incorporated in the polyester by reactive blending with recycled terephthalate polyesters. A new method for BHEEB synthesis by chemical recycling of PC is also presented.

Glass transition temperature (Tg) as function of BHEEB content for copolyesters prepared by reactive blending BHEEB with terephthalate polyesters.

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Glass transition temperature (Tg) as function of BHEEB content for copolyesters prepared by reactive blending BHEEB with terephthalate polyesters.
Water‐Soluble AmphiphilicO‐(Carboxymethyl)cellulose Derivatives – Synthesis and Properties
Authors: Sroková Iva , Tomanová Vladimíra , Ebringerová Anna , Malovíková Anna , Heinze Thomas
Published: February 2004

Summary:Water‐soluble, partially hydrophobized derivatives ofO‐(carboxymethyl)cellulose (CMC) were prepared by esterification of CMC in its ‘gel suspension’ form. The classical esterification method (A) using stearoyl chloride/pyridine as well as two unconventional methods based on reaction with mixed anhydrides (B) and transesterification with vinyl laurate (C) respectively, were compared in terms of the structural, molecular and performance properties of the obtained derivatives. The classical esterification and method B yielded water‐soluble simple fatty acid esters, whereas mixed acetic‐fatty acid esters were obtained by method C. In all cases, molecular degradation of CMC was observed.1H and13C NMR spectroscopy of the acetyl‐lauroyl derivatives of CMC with a degree of esterificationDSEof 0.20 indicated a prevalence of the lauroyl groups (DSAc:DSLa = 0.03:0.17). Most of the water‐soluble derivatives exhibited excellent emulsifying efficiency. They represent polysaccharide‐based surfactants with effective anti‐redeposition properties as well as good washing power. Suitable derivatives can be prepared under mild reaction conditions by both unconventional methods which implies that they have potential as substitutes for the expensive and invasive conventional method.

Preparation of CMC derivatives.

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Preparation of CMC derivatives.
Dynamic Mechanical Properties of Poly(propylene) Blends with Poly[ethylene‐co‐(methyl acrylate)]
Authors: Genovese Antonietta , Shanks Robert A.
Published: February 2004

Summary: Blends of poly(propylene) (PP) were prepared with poly[ethylene‐co‐(methyl acrylate)] (EMA) having 9.0 and 21.5% methyl acrylate comonomer. A similar series of blends were compatibilized by using maleic anhydride grafted PP. The morphology and mechanical properties of the blends were investigated using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) in tensile mode. The DMA method and conditions were optimized for polymer film specimens and are discussed in the experimental section. The DSC results showed separate melting that is indicative of phase‐separated blends, analogous to other PP‐polyethylene blends but with the added polarity of methyl acrylate pendant side groups that may be beneficial for chemical resistance. Heterogeneous nucleation of PP was decreased in the blends because of migration of nuclei into the more polar EMA phase. The crystallinity and peak‐melting temperature did not vary significantly, although the width of the melting endotherm increased in the blends indicating a change had occurred to the crystals. DMA analysis showed the crystal‐crystal slip transition $T_{\rm \alpha }^*$ and glass transition (Tg) for PP as well as a Tg of the EMA copolymer occurring chronologically toward lower temperatures. The storage modulus of PP and the blends was generally greater with annealing at 150 °C compared with isothermal crystallization at 130 °C. The storage modulus of the blends for isothermally crystallized PP increased with 5% EMA, then decreased for higher amounts of EMA. Annealing caused a decrease with increasing copolymer content. The extent of the trend was greater for the compatibilized blends. The Tg of the blends varied over a small range, although this change was less for the compatibilized blends.

Storage modulus for PP and EMA9.0 blends annealed at 150 °C.

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Storage modulus for PP and EMA9.0 blends annealed at 150 °C.
Preparation and Characterization of Chitosan‐Gellan Hybrid Capsules Formed by Self‐Assembly at an Aqueous Solution Interface
Authors: Ohkawa Kousaku , Kitagawa Takeshi , Yamamoto Hiroyuki
Published: February 2004

Summary: True spherical capsules are formed by electrostatic polysaccharide interaction between chitosan and gellan gum via polyion complex (PIC) formation in aqueous solutions. Dropwise addition of a chitosan solution into the gellan solution gave spherical capsules whose outside surface was gellan and whose inside was chitosan (chitosanin‐gellanout capsule). Conversely, the addition of gellan into chitosan yields chitosanout‐gellanin capsules. SEM observation revealed a fibrous network spreading along the capsule membrane of the chitosanin‐gellanout capsule. The releasing properties of the capsules were examined using low molecular weight substances and high molecular weight proteins. For low molecular weight substances, the releasing kinetics were affected by the attractive and repulsive interactions between the substances and the inside component of the capsule. The molecular weight of the encapsulated substances also affects the releasing kinetics. These results, together with a simple preparation procedure, indicate the applicability of chitosan‐gellan capsules as drug‐carrier materials having a controlling release mechanism. As an application example, preparation of an actually eatable artificial roe was also described.

Illustrative drawing of PIC capsule formation.

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Illustrative drawing of PIC capsule formation.
Improvement of Chromatic Aberration of the Plastic Rod‐Lens Array, 2
Authors: Uozu Yoshihiro , Hirota Norifumi , Horie Kazuyuki
Published: February 2004

Summary: We propose in this paper a new plastic rod‐lens with low chromatic aberration. Since a plastic rod‐lens has a parabolic refractive index distribution, it usually also shows a distribution of Abbe number. This Abbe number distribution is thought to cause the chromatic aberration of the plastic rod‐lens array. We have studied novel materials for a new plastic rod‐lens with low chromatic aberration and have provided new transparent polymer blends consisting of two polymers with different refractive indices and with almost equal Abbe numbers by using a fabrication process based on photopolymerization of methacrylate monomer(s) in the presence of other methacrylic polymers. The process can give new transparent polymer blends which cannot be formed using conventional techniques for polymer blend formation. In this work, tricyclo[5,2,1,02,6]deca‐8‐yl methacrylate is used as a high refractive index monomer and tert‐butyl methacrylate is used as a low refractive index one. By using polymer blends including these monomer units, we have created a plastic rod‐lens with lower chromatic aberration.

Molecular structures of comonomers in the study.

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Molecular structures of comonomers in the study.
Synthesis and Characterisation of Anhydride‐Cured Epoxy Nanocomposites Containing Layered Silicates Modified with Phenolic Alkylimidazolineamide Cations
Authors: Fröhlich Jörg , Golombowski Dietmar , Thomann Ralf , Mülhaupt Rolf
Published: February 2004

Summary: Phenolic alkylimidazolineamides were prepared and applied as modifiers in order to render layered silicates organophilic and to prepare polymeric nanocomposites. The imidazolineamine, 2‐{2‐[heptadec‐8‐enyl]‐4,5‐dihydro‐1‐imidazol‐1‐yl}‐1‐ethaneamine (IA), was reacted in bulk with one of the two phenolic compounds, ethyl 4‐hydroxybenzoate (P) or methyl 3‐[3,5‐di(tert‐butyl)‐4‐hydroxyphenyl]propionate (HP), which is an intermediate for antioxidants, to prepare the two phenolic imidazolineamides, PIA and HPIA. During protonation in water, both phenolic imadazolineamides were used successfully to exchange interlayer sodium cations of sodium bentonite and fluorohectorite, thus producing organophilic layered silicates with an increased interlayer distance of around 3.3 nm. The new phenolic organophilic layered silicates represent a novel class of phenolic organic/inorganic hybrid materials. They were applied as fillers in hexahydrophthalic anhydride‐cured bisphenol‐A diglycidyl ether (BADGE). Thermal analysis (DSC), transmission electron microscopy (TEM), wide angle X‐ray scattering (WAXS), and mechanical tests were used to evaluate the thermal, mechanical, and morphological properties. Although fracture toughness, measured as the stress intensity factor, KIc, and the energy release rate, GIc, increased by around 50% with increasing silicate content without sacrificing glass temperature, both tensile strength and Young's modulus increased only marginally. Low matrix reinforcement was attributed to inadequate compatibility matching, as evidenced by the slightly lower interlayer distances of the layered silicates encapsulated in the epoxy matrix.

Representative TEM micrographs of the sample ER‐bent‐PIA/10.

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Representative TEM micrographs of the sample ER‐bent‐PIA/10.
Brittle‐Ductile Transition and Toughening Mechanism in POM/TPU/CaCO3 Ternary Composites
Authors: Gao Xiaoling , Qu Cheng , Zhang Qin , Peng Ya , Fu Qiang
Published: February 2004

Summary: Polyoxymethylene (POM)/elastomer/filler ternary composites were prepared, in which thermoplastic polyurethane(TPU) and an inorganic filler, CaCO3, were used to achieve balanced mechanical properties of POM. A two‐step processing method, in which the elastomer and the filler were mixed to a masterbatch first and then the masterbatch was melt‐blended with pure POM, was used to obtain a core‐shell microstructure with CaCO3 covered by TPU. A brittle‐ductile transition phenomenon was observed with increasing TPU content for this ternary system. To better understand the toughening mechanism, we investigated the fractured surface, interparticle distance, and the spherulite size of POM as function of the TPU and CaCO3 content. The critical TPU content depended on not only the content of CaCO3, but also the size of CaCO3 particles. The observed brittle‐ductile transition was discussed based on the crystallinity and spherulite size of POM as well as Wu's critical interparticle distance theory. The results showed that the impact strength of POM/TPU/CaCO3 ternary system depends on a critical, interparticle distance, which varies from one system to another. The dependence of the impact strength on the spherulite size was considered for the first time, and a single curve was constructed. A critical spherulite size of 40 micron was found, at which brittle‐ductile transition occurs, regardless of the TPU and CaCO3 content or the size of CaCO3 particles. Our results indicate that the spherulite size of POM indeed plays a role in determining the toughness, and must be considered when discussing the toughening mechanism.

Izod impact strength vs. the crystal size for POM/TPU blends and POM/TPU/CaCO3 ternary composites.

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Izod impact strength vs. the crystal size for POM/TPU blends and POM/TPU/CaCO3 ternary composites.
The Solid State Postcondensation of PET, 1
Authors: Gantillon Barbara , Spitz Roger , McKenna Timothy F.
Published: February 2004

Summary: A review of the processes underlying the solid state postcondensation of poly(ethylene terephthalate) (PET) is presented. Fundamental aspects of the reactions are treated, and it is shown that the rate of polycondensation in the solid state depends on the relative rates of two types of diffusion. On the one hand, the diffusion of reaction by‐products (physical diffusion) controls the rate of the forward reactions. And on the other hand the diffusion of end‐groups (chemical diffusion) allows the reaction to proceed.

The transesterification of BHET to form PET.

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The transesterification of BHET to form PET.
The Solid State Postcondensation of PET, 2
Authors: Gantillon Barbara , Spitz Roger , McKenna Timothy F.
Published: February 2004

Summary: A process for the solid state polycondensation of PET is proposed. It is shown that by correctly choosing the prepolymerisation conditions it is possible to crystallise the product and to directly polymerise it in a dispersed phase. This process is significantly faster than the “standard” PET processes, and allows one to obtain high molecular weights directly from a prepolymer without the need to use an intermediate solution polymerisation step.

Reactor set‐up for precursor preparation and dispersed phase prepolymerisation.

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Reactor set‐up for precursor preparation and dispersed phase prepolymerisation.
The Solid State Postcondensation of PET, 3
Authors: Gantillon Barbara , Spitz Roger , McKenna Timothy F.
Published: February 2004

Summary: It was demonstrated that it is possible to produce prepolymers with a number‐average degree of polymerisation on the order of 5–40 directly in a liquid‐liquid dispersion in less than three hours. It was also shown that prepolymers made via this route and rapidly crystallised by the addition of a dispersant at ambient temperature are more porous than prepolymers made in an industrial liquid melt process.

SEM micrograph of prepolymers pLL‐PTA with \overline {DP} _{\rm n} = 28, dp ∈ 63–125 μm.

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SEM micrograph of prepolymers pLL‐PTA with \overline {DP} _{\rm n} = 28, dp ∈ 63–125 μm.
The Solid State Postcondensation of PET, 4
Authors: Gantillon Barbara , Spitz Roger , Lepage Jean‐Luc , McKenna Timothy F.
Published: February 2004

Summary: A new method of polymerising PET in the solid state is proposed in either a gas phase reactor, or in hydrocarbon dispersion. It is shown that the reaction can be carried out efficiently at temperatures on the order of 200–240 °C directly from a prepolymer without the need for a melt phase step. It is shown that the crystal structure of the prepolymer plays a determining role in the kinetics of the SSP reaction.

Schema of the reactor used for gas phase SSP.

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Schema of the reactor used for gas phase SSP.
Polyolefins with Long Chain Branches Made with Single‐Site Coordination Catalysts: A Review of Mathematical Modeling Techniques for Polymer Microstructure
Authors: Soares João B. P.
Published: February 2004

Summary: Single‐site coordination polymerization catalysts are considered one of the most important developments on the technology of olefin polymerization during the last two decades. Among the several new capabilities of these catalysts is the ability to produce polymer molecules having narrow molecular weight distribution and long chain branches. These advances in polymer synthesis have stimulated the development of mathematical models to describe and predict several features of their molecular architectures. Many modeling techniques have been used for this purpose, including instantaneous distributions, population balances, the method of moments, and Monte Carlo simulations. This article reviews the mathematical models developed over the last decade to quantify the microstructure of polymers made with single‐site catalysts with special emphasis on the mechanism of long chain branch formation by terminal branching.

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Cover Picture: Macromol. Mater. Eng. 1/2004
Authors: Uozu Yoshihiro , Hirota Norifumi , Horie Kazuyuki
Published: February 2004

Cover: Plastic rod‐lens arrays have been limitedly applied to white/black facsimiles and scanners because of their large chromatic aberration. Plastic rod‐lens with lower chromatic aberration can be realized by using new transparent polymer blends with a small dispersion of Abbe numbers.

Further details can be found in the Full Paper by Y. Uozu,* N. Hirota, and K. Horie on page 56.
Homo‐ and Copolymerization of Butadiene Catalyzed by an Bis(imino)pyridyl Vanadium Complex
Authors: Colamarco Elena , Milione Stefano , Cuomo Cinzia , Grassi Alfonso
Published: February 2004

Summary: The bis(imino)pyridyl vanadium(III) complex [VCl3{2,6‐bis[(2,6‐iPr2C6H3)NC(Me)]2(C5H3N)}] activated with different aluminium cocatalysts (AlEt2Cl, Al2Et3Cl3, MAO) promotes chemoselective 1,4‐polymerization of butadiene with activity values higher than classical vanadium‐chloride‐based catalysts. The polymer structure depends on the nature of the cocatalyst employed. The MAO‐activated complex was also found to be active in ethylene‐butadiene copolymerization, producing copolymers with up to 45 mol‐% of trans‐1,4‐butadiene. Crystalline polyethylene and trans‐1,4‐poly(butadiene) segments were detected in these copolymers by DSC and 13C NMR spectroscopy.

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New Positive‐Type Photoresists Based on Enzymatically Synthesized Polyphenols
Authors: Kadota Joji , Fukuoka Tokuma , Uyama Hiroshi , Hasegawa Kiichi , Kobayashi Shiro
Published: February 2004

Summary: New positive‐type photoresist systems based on enzymatically synthesized polyphenols have been developed. The photoresist thin film consisting of the polyphenol and a diazonaphthoquinone derivative was prepared on copperfoil‐coated epoxy resins and exposed to UV light with different doses. The polyphenols from the bisphenol monomers exhibited high photosensitivity, comparable with a conventional cresol novolac. The sensitivity could be controlled by changing the structure of the polyphenols. Furthermore, the present photoresist showed excellent etching resistance.

Characteristic exposure curves of poly(1)/DNQ and poly(5)/DNQ (both 70:30 wt.‐%) with different phenylene unit contents.

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Characteristic exposure curves of poly(1)/DNQ and poly(5)/DNQ (both 70:30 wt.‐%) with different phenylene unit contents.
Block Copolymers in Emulsion and Dispersion Polymerization
Authors: Riess Gérard , Labbe Clorinthe
Published: February 2004

Summary:This article deals with recent progress including the authors' work concerning the application of block copolymers as polymeric surfactants in heterophase polymerizations. The synthesis methods for preparing block copolymers by emulsion and dispersion techniques are outlined, with emphasis on recently developed controlled free radical polymerizations in aqueous media. Specific characteristics of amphiphilic block copolymers are described, for example, micellization and emulsifying effects. A general overview of emulsion and dispersion polymerization in an aqueous and organic medium with ionic and nonionic block copolymers is presented for the preparation of electrosteric and sterically stabilized latex particles. Typical examples of microemulsion, miniemulsion, oil‐in‐oil emulsion, and micellar polymerizations are provided. Current and potential developments of so‐called “hairy latexes”, inverse‐, multiple‐, and solid emulsions, as well as of nonaqueous polymeric dispersions are also discussed.

PS foam obtained by free radical polymerization of water‐in‐styrene, stabilized with a PS–PEO diblock copolymer.

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PS foam obtained by free radical polymerization of water‐in‐styrene, stabilized with a PS–PEO diblock copolymer.
Polyurethanes with Pendant Hydroxyl Groups: Synthesis and Characterization
Authors: Ubaghs Luc , Fricke Nicole , Keul Helmut , Höcker Hartwig
Published: February 2004

Communication: Phenoxycarbonyloxymethyl ethylene carbonate 4 was synthesized from glycerol carbonate and phenyl chloroformate. Polyurethanes with pendant hydroxyl groups were obtained from polycondensation reactions of this AA* monomer with diamines. These polymers contain primary as well as secondary hydroxyl groups. The obtained polyurethanes are amorphous materials. The glass transition temperature decreases with increasing number of methylene groups between the urethane groups.

As the number of methylene groups increases between the urethane groups, the glass transition temperature of the polymer decreases.

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As the number of methylene groups increases between the urethane groups, the glass transition temperature of the polymer decreases.
Novel Mechanism for Layered Silicate Clay Intercalation by Poly(propylene oxide)‐Segmented Carboxylic Acid
Authors: Lin Jiang‐Jen , Chang Yu‐Chung , Cheng I‐Jein
Published: February 2004

Summary: Poly(propylene oxide)‐amidoacids were used to intercalate montmorillonite clay to afford organoclays with an X‐ray basal spacing as wide as 81 Å. Differing from the ionic exchange between quaternary ammonium salts and the metal ions in clays, the intercalation mechanism involves a beta‐amidoacid chelation with sodium ions in the silicate interlayer confinement. With the end groups tethered on the silicate surface, the hydrophobic poly(propylene oxide)‐backbones self‐aggregate and consequently widen the interlayer space between neighboring silicate plates.

Postulated structure of the chelation of sodium ions by the poly(propylene oxide)‐amido acid.

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Postulated structure of the chelation of sodium ions by the poly(propylene oxide)‐amido acid.
Polymer Architectures Consisting of Rotating Fibers Prepared by Photopolymerization in a Cholesteric Phase
Authors: Kihara Hideyuki , Miura Toshiaki , Kishi Ryoichi
Published: February 2004

Summary: Hydrogen‐bonded polymer films consisting of fine, extended fibers were prepared by photopolymerization of an acrylate monomer containing a benzoic acid group in the fingerprint or Grandjean textures of a cholesteric liquid‐crystalline mixture. Scanning electron microscopy and circular dichroism spectroscopy revealed that the fibers, measuring about 400 nm in diameter, formed helical superstructures and that their helical axes corresponded to the cholesteric helical axes that existed in the LC mixture before photopolymerization.

SEM image of a polymer film.

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SEM image of a polymer film.
Depth Profiling by AFM Nanoindentations and Micro‐FTIR Spectroscopy for the Study of Polymer Ageing
Authors: Mailhot Bénédicte , Bussière Pierre‐Olivier , Rivaton Agnès , Morlat‐Thérias Sandrine , Gardette Jean‐Luc
Published: February 2004

Summary: A method of depth profiling by AFM nanoindentations is developed for the characterisation of the heterogeneity of the mechanical properties of oxidised polymers. An increase or a decrease of the sample stiffness is measured close to the surface. A comparison with micro‐FTIR profiles and a knowledge of the photooxidation mechanism permit an interpretation of the chemical and physical changes and give new insights into the understanding of the ageing behaviour.

Photooxidation profile of a TMPC film measured by AFM (•) and by micro‐FTIR (♦) after irradiation.

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Photooxidation profile of a TMPC film measured by AFM (•) and by micro‐FTIR (♦) after irradiation.
Acrylic, Elastomeric, Particle‐Dispersed Epoxy‐Clay Hybrid Nanocomposites: Mechanical Properties
Authors: Balakrishnan Subramanian , Raghavan Dharmaraj
Published: February 2004

Summary: Nanocomposites were formulated by curing a sonicated mixture of epoxy resin, C18 clay, and acrylic rubber dispersants. At 5.5 phr (parts per hundred) organoclay loading and a rubber concentration of 15 phr, the tensile‐failure strain of the nanocomposite was found to be higher than that of epoxy nanocomposite, rubber‐dispersed epoxy, and pristine epoxy. A plausible mechanism for improvement of the failure strain of nanocomposites is proposed.

Stress strain curves of filled and unfilled epoxy specimen.

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Stress strain curves of filled and unfilled epoxy specimen.
Phenoxy–Ether Ligated Ti Complexes for the Polymerization of Ethylene
Authors: Suzuki Yasuhiko , Inoue Yoshihisa , Tanaka Hidetsugu , Fujita Terunori
Published: February 2004

Summary: Bis(phenoxy–ether) Ti complexes were investigated as ethylene polymerization catalysts. The complexes, combined with iBu3Al/Ph3CB(C6F5)4 or methylaluminoxane (MAO) cocatalysts, can be highly active single‐site catalysts, which display activities ( turnover frequency, max. 2 065 min−1) comparable with that of a highly active bis(phenoxy–imine) Ti complex/MAO system, and provide very high molecular weight polyethylenes ($\overline M _{\rm v}$ 2 040 000–5 420 000) at 25 °C under atmospheric pressure.

Synthesis of polyethylene using bis(phenoxy–ether) Ti complexes, an example of which is shown.

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Synthesis of polyethylene using bis(phenoxy–ether) Ti complexes, an example of which is shown.
Ethylene Polymerization Catalyzed by Titanium(IV) Complexes of a Triaryloxoamine Ligand [TiX{(OArCH2)3N}]
Authors: Wang Wei , Fujiki Michiya , Nomura Kotohiro
Published: February 2004

Summary: Titanium complexes containing a triaryloxoamine ligand, [TiX{(O‐2,4‐R2C6H2‐6‐CH2)3N}] (R = Me, tBu; X = OiPr, O‐2,6‐iPr2C6H3), exhibited notable catalytic activity for ethylene polymerization in the presence of MAO, especially at temperatures between 100 and 120 °C. Their activity increased upon the addition of a small amount of AlMe3.

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Green Polymer Chemistry: Microwave‐Assisted Single‐Step Synthesis of Various (Meth)acrylamides and Poly(meth)acrylamides Directly from (Meth)acrylic Acid and Amines
Authors: Goretzki Christian , Krlej Andrea , Steffens Christopher , Ritter Helmut
Published: February 2004

Summary: Various (meth)acrylamides were synthesized in good yields directly from (meth)acrylic acid and an amine using microwave irradiation in a solvent‐free environment. Under the applied conditions the (meth)acrylic function is preserved. Furthermore, the addition of an initiator like 2,2′‐azoisobutyronitrile (AIBN) to the starting mixture leads directly to poly(meth)acrylamides in a single step.

General reaction scheme for the formation of poly(meth)acrylamides from the microwave‐assisted reaction of (meth)acrylic acid and various amines.

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General reaction scheme for the formation of poly(meth)acrylamides from the microwave‐assisted reaction of (meth)acrylic acid and various amines.
Controlled/Living Radical Polymerization of Methacrylic Monomers in the Presence of Lewis Acids: Influence on Tacticity
Authors: Lutz Jean‐François , Jakubowski Wojciech , Matyjaszewski Krzysztof
Published: February 2004

Summary: Atom transfer radical polymerization (ATRP) and reversible addition‐fragmentation transfer (RAFT) polymerization of N‐methyl methacrylamide and methyl methacrylate were investigated in the presence of rare‐earth triflates known to enhance polymer isotacticity. Poly(N‐methyl methacrylamide) with controlled molecular weight, low polydispersity, and enhanced isotacticity was prepared by ATRP and RAFT in the presence of catalytic amounts of yttrium trifluoromethanesulfonate or ytterbium trifluoromethanesulfonate. The tacticity of poly(N‐methyl methacrylamide) depends on the Lewis acid concentration: well‐defined polymers with predominantly either syndiotactic, atactic, or isotactic triads were prepared by adjusting the concentration of the Lewis acid. Simultaneous control of molecular weights, polydispersities, and tacticities in the polymerization of methyl methacrylate was less successful.

Free radical propagation in the presence of a Lewis acid (LA) giving rise to chelate control.

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Free radical propagation in the presence of a Lewis acid (LA) giving rise to chelate control.
The Resting State Makes the Difference: The Influence of the Anchor Group in the ROMP of Norbornene Derivatives
Authors: Slugovc Christian , Demel Sandra , Riegler Silvia , Hobisch Josefine , Stelzer Franz
Published: February 2004

Summary: A model study with four norbornene derivatives with different groups connecting a functional unit to the norbornene reveals that the “anchor groups” influence the polymerisation rate constants of ring opening metathesis (ROM) polymerisations. Consequently, polydispersities and molecular weights are affected. The observed effects are explained by different tendencies of the anchor groups to coordinate to the ruthenium centre during the resting state of the propagation.

A functionalised monomer where F is the functional unit, S is a spacer, A is an anchor group and P is the polymerisable group.

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A functionalised monomer where F is the functional unit, S is a spacer, A is an anchor group and P is the polymerisable group.