Showing papers in "Polymer Bulletin in 1984"
169 citations
TL;DR: In this paper, the conductivity anisotropy of poly(p-phenylene vinylene) (PPV) has been investigated for charge transport in highly conjugated conducting polymers.
Abstract: The study of charge transport mechanisms in highly conjugated conducting polymers has historically been hampered by the complex and invariant morphologies of the best conductors We have prepared amorphous and uniaxially oriented films of poly(p-phenylene vinylene) (PPV) which exhibit a large conductivity anisotropy proportional to the degree of molecular orientation The conductivity of the AsF5 doped PPV, together with wide angle x-ray and IR characterization of these samples is reported
127 citations
TL;DR: By melting condensation of terephthalic acid dichloride and 1,4∶3,6-dianhydrohexitols as well as selectively prepared lower oligomers thereof the formation of polyterephthalates is achieved.
Abstract: By melting condensation of terephthalic acid dichloride and 1,4∶3,6-dianhydrohexitols as well as selectively prepared lower oligomers thereof the formation of polyterephthalates is achieved These polyesters are characterized by 1H-NMR spectra vapour pressure osmometry (VPO), differential scanning calorimetry (DSC), viscosity measurements and combustion analyses Their preparation and properties are discussed
93 citations
TL;DR: In this paper, the AB and ABA type block copolymers were obtained by using the polymers obtained by BDC and XDC as polymeric photo-iniferters of the polymerization of second monomers.
Abstract: To design the structure of the block copolymers by radical polymerization, benzyl N,N-diethyldithiocarbamate (BDC) and p-xylylene N,N-diethyldithiocarbamate(XDC) were used as mono- and bifunctional photo-iniferters, respectively, for the polymerizations of styrene(St) and methyl methacrylate (MMA). These polymerizations proceeded via a living radical mechanism. When the ratio of the concentration of the diethyldithiocarbamate group to that of a photo-iniferter molecule was kept constant, the yields of the polymers obtained by both BDC and XDC were identical, and their molecular weights (¯M) by XDC were two times as high as those by BDC. This observation strongly suggested that the polymerizations by BDC and XDC were performed by living mono- and biradical mechanisms, respectively. By using the polymers obtained by BDC and XDC as polymeric photo-iniferters of the polymerization of second monomers, the AB and ABA type block copolymers were obtained, respectively.
90 citations
TL;DR: In this paper, the preparation of fully oriented non-fibrous crystalline polyacetylene is demonstrated, which exhibits a compact and homogeneous morphology, whereas sharp and well defined electron diffraction (HEED) patterns indicate a fully oriented crystalline transpolyacetylene material.
Abstract: The preparation of fully oriented non-fibrous crystalline polyacetylene is demonstrated. Poly-7,8-bis-(trifluoromethyl)-tricyclo-[4.2.2.0]-deka-3,7,9-triene, poly-(BTFM-TCDT), is polymerized by a ring opening metathetical polymerization. Films cast from a solution of poly-(BTFM-TCDT) (precursor polymer) can be converted to polyacetylene by heating. During this conversion process an uniaxial stress is applied to the precursor polymer film which results in a high orientation of the polymer chains. SEM pictures show a compact and homogeneous morphology, whereas sharp and well defined electron diffraction (HEED) patterns indicate a fully oriented crystalline transpolyacetylene material. Consequently we present polarized infrared spectra, expecially for the C-H out-of-plane deformation vibration (1010 cm−1), which exhibit a tremendous dichroism for infrared radiation polarized parallel and perpendicular to the chain axis (c-axis, orientation direction).
88 citations
TL;DR: In this paper, a low density polyurethane foams (ca. 2 lbs/cu. ft.) with acceptable strength and excellent flammability resistance properties were formulated with a commercial furan polyol containing 20% hydroxypropyl lignin derivative.
Abstract: Low density polyurethane foams (ca. 2 lbs./cu. ft.) with acceptable strength and excellent flammability resistance properties were formulated with a commercial furan polyol containing 20% hydroxypropyl lignin derivative. Propylene oxide-modified lignin from two sources, kraft and organosolv lignin, were employed. The organosolv lignin derivative exhibited better foaming characteristics than the corresponding kraft lignin, which collapsed when the rising foam was touched for testing. The weight contribution of lignin derivative was limited to 20% by compatibility with the fluorocarbon blowing agent, and solubility in polyol. Preliminary tests encourage further research on structural materials containing hydroxypropyl lignin derivatives.
82 citations
TL;DR: In this article, a rod-like poly(tert-butyl fumarate (DtBF) was found to homopolymerize easily with 1,1′-azobisisisobutyronitrile and benzoyl peroxide as radical initiators at 50~80°C to give a non-flexible rodlike polymer with number-average molecular weight of more than 100,000.
Abstract: Di-tert-butyl fumarate (DtBF) was found to homopolymerize easily with 1,1′-azobisisobutyronitrile and benzoyl peroxide as radical initiators at 50~80°C to give a nonflexible rod-like polymer, poly(tert-butoxycarbonylmethylene) with number-average molecular weight of more than 100,000. The colorless powderlike polymer thus obtained was soluble in benzene, toluene, carbon tetrachloride and tetrahydrofuran, and gave a transparent film or fiber from its toluene solution. This polymer did not melt, but it underwent degradation with a quantitative elimination of isobutene at 180~190°C. The remaining polymer was confirmed to be a pure poly(fumaric acid), poly(hydroxycarbonylmethylene). Therefore, the degradation of poly(DtBF) in solution at 180~190°C was found to be a new route for synthesizing of a high molecular weight poly(fumaric acid).
57 citations
TL;DR: A conceptually simple model for free-radical cross-linking polymerization that yields qualitative agreement with experiments on the conversion dependence of the number of pendant double bonds is performed.
Abstract: Simulations of a conceptually simple model for free-radical cross-linking polymerization have been performed in relation to experimental indications for (temporary) microgel particles. Many qualitative features ascribed to microgels show up in the simulation. In particular this model yields qualitative agreement with experiments on the conversion dependence of the number of pendant double bonds.
57 citations
TL;DR: In this paper, a brief summary of the basic aspects of supercritical fluids is given, and the application of this novel technique for the fractionation and purification of polymeric and oligomeric organofunctional siloxanes is illustrated.
Abstract: Supercritical fluids which combine the properties of both gases and liquids also show very unusual pressure dependent dissolving power. When such fluids are used as solvents in various separation processes, it is possible to achieve effective fracticnation or purification in a number of different systems which are difficult to obtain by conventional techniques. In this communication a brief summary of the basic aspects of supercritical fluids will be given. The application of this novel technique for the fractionation and purification of polymeric and oligomeric organofunctional siloxanes will be illustrated.
55 citations
TL;DR: Taniguchi et al. as discussed by the authors investigated the states of water in gel cellophane membranes by DSC measurements and found that the ratio of nonfreezing water (often referred to as bound water) to the dry membrane (g) was 1.06.
Abstract: The states of water in gel cellophane membranes were investigated by DSC measurements. An extra exothermic peak, which has not previously been reported, was observed at heating rates slower than 2.5K/min. The peak was ascribed to the crystallization of the liquid water in the heating process. The ratio of the nonfreezing water (often referred to as bound water) (g) to the dry membrane (g) was estimated to be 1.06. This value is far larger than the bound water contents reported for cellulose acetate membranes (Frommer et al. 1972, Taniguchi et al. 1975).
55 citations
TL;DR: In this article, a series of poly(aryl-ether-ether,ether-ketone) (PEEK) plaques of differing crystallinity was investigated using infrared reflection spectroscopy.
Abstract: Infrared reflection spectroscopy has been used to investigate a series of poly(aryl-ether-ether-ketone) (PEEK) plaques of differing crystallinity. Correlations have been observed between intensity changes in the reflection spectra and the crystallinity as measured by wide angle X-ray scattering (WAXS). These correlations enable estimates to be made of the crystallinity close to the surface and complement the bulk data obtained by WAXS.
TL;DR: In this paper, two new synthetic methods for the preparation of functional polymers containing 2-oxazoline pendant groups are presented, one of which is based on phase transfer catalyzed etherification of 2-(p-hydroxyphenyl)-2-oxozoline with a mixture of m- and p-chloromethylstyrene.
Abstract: Two new synthetic methods for the preparation of functional polymers containing 2-oxazoline pendant groups are presented. The first one consists on the phase transfer catalyzed etherification of 2-(p-hydroxyphenyl)-2-oxazoline with a mixture of m- and p-chloromethylstyrene to provide, after separation, m- and p-vinylbenzyl ethers of 2-(p-hydroxyphenyl)-2-oxazoline. Both monomers can be polymerized by a radical mechanism to provide polystyrene containing 2-oxazoline pendant groups. The second method represents a phase transfer catalyzed etherification of a poly(2,6-dimethyl-1,4-phenylene oxide) containing pendant bromomethyl groups with 2-(p-hydroxyphenyl)-2-oxazoline. Incomplete etherification of the bromobenzyl groups in this case, leads to the first example of a functional polymer containing not only cationically polymerizable heterocycles, but also their own cationic initiator as pendant groups.
TL;DR: In this article, the effect of groups formed during termination of polymerization on the thermal stability of poly(methyl methacrylate) oligomers was investigated and it was found that oligomers with a head-to-head linkage were the least thermally stable, degrading at temperatures around 190°C.
Abstract: Methyl methacrylate oligomers have been synthesised and used as models to probe the effect of groups formed during termination of polymerization on the thermal stability of poly(methyl methacrylate). Oligomers containing a head-to-head linkage were found to be the least thermally stable, degrading at temperatures around 190°C. In comparison, oligomers containing unsaturated end groups degrade at 255°C, while models containing saturated terminal units are relatively stable and only degrade at temperatures in excess of 300°C.
TL;DR: In this paper, the authors measured the temperatur dependence of self diffusion coefficients of polystyrene and polyethylene in the melt with the pulsed field gradient nmr technique and described the temperature and molar mass dependences of the self diffusion coefficient can be described by the free volume model.
Abstract: The temperatur dependence of the self diffusion coefficients of polystyrene and polyethylene in the melt was measured with the pulsed field gradient nmr technique. The temperature and molar mass dependences of the self diffusion coefficients can be described by the free volume model. Taking into account the matrix effect we detected the beginning of the break of the reptation process for polystyrene at low molar masses. The activation energies of the self diffusion process are comparable with those observed for viscosity.
TL;DR: Fractionnement d'oligodimethylsiloxanes avec des groupes terminaux α,ω-carboxypropyl, de masse moleculaire 2000 et 6400, a l'aide de CO 2
Abstract: Fractionnement d'oligodimethylsiloxanes avec des groupes terminaux α,ω-carboxypropyl, de masse moleculaire 2000 et 6400, a l'aide de CO 2
TL;DR: In this paper, the 13C spin-lattice relaxation times T1 of hydrolysed cotton cellulose have been determined in the solid state, and spectral assignment of the C2-C3-C5 region is proposed.
Abstract: The 13C spin-lattice relaxation times T1 of hydrolysed cotton cellulose have been determined in the solid state. T1 is between 202 and 266 seconds in the crystalline regions of the sample for all the carbons in the anhydroglucose unit and less than 15 seconds in the amorphous part. Based on the relaxation data, spectral assignment of the C2-C3-C5 region is proposed.
DSM1
TL;DR: In this paper, a high density polyethylene (HDPE) and a low density polyylene (LDPE), were fractionated by means of preparative GPC and analytical GPC, direct extraction, and a crystallization/dissolution method, to enable determination of the chain branching distribution over the molar mass distribution.
Abstract: A high density polyethylene (HDPE) and a low density polyethylene (LDPE) were fractionated by means of preparative GPC, analytical GPC, direct extraction, and a crystallization/dissolution method, to enable determination of the chain branching distribution over the molar mass distribution. The non-isothermal crystallization and melting behaviour of the HDPE and LDPE fractions and of a series of linear polyethylene (LPE) fractions was studied using DSC with a scanning rate of 5 K/min. After an initial increase, the crystallization temperature of the LPE fractions started to decrease at M−20 kg/mol, to remain at a constant value from M−60 kg/mol. This is illustrative of the crystallization being hindered by entanglements. With LDPE fractions showing a constant degree of short chain branching an analogous, but greater, decrease was observed in a corresponding range of molecular dimensions. The differences found for the HDPE fractions as compared with the LPE reference values are due mainly to short chain branching.
TL;DR: The transition properties of poly(vinylidenefluoride) and related copolymers, either semicrystalline or amorphous, were studied by differential scanning calorimetry in the temperature range from 200 K to 500 K as discussed by the authors.
Abstract: The transition properties of poly(vinylidenefluoride) and of some related copolymers, either semicrystalline or amorphous, were studied by differential scanning calorimetry in the temperature range from 200 K to 500 K. The amorphous copolymers exhibit a single glass transition. Melting endotherms and a lower glass transition [Tg(L)] are systematically observed in the semi-crystalline materials as well as an upper glass transition [Tg(U)] for certain thermal and mechanical histories of the samples. Conditions for [Tg(U)] existence are related to solid state morphology of the macromolecules and loop length in the folded chains.
TL;DR: In this article, the synthesis of polyalkylmethacrylate macromonomers has been performed anionically by direct deactivation of the carbanionic sites with p-vinyl-or p-isopropenylbenzyl bromide.
Abstract: The synthesis of polyalkylmethacrylate macromonomers has been performed anionically by direct deactivation of the carbanionic sites with p-vinyl-or p-isopropenylbenzyl bromide. The characterization of the samples proved that the yields are close to quantitative, and that no side reactions are involved. The method also applies to hydroxyethylmethacrylate and to glycerylmethacrylate, provided the monomers are made aprotic by reversible silylation or acetalization.
TL;DR: In this paper, the authors gave experimental evidence for two different ordered conformations in solution for the xanthan molecules and their hydrodynamic characteristics are quite different and their existence is controlled by experimental conditions.
Abstract: This paper gives experimental evidence for two different ordered conformations in solution for the xanthan molecules. Their hydrodynamic characteristics are quite different and their existence is controlled by experimental conditions.
TL;DR: In this article, the interaction of polyelectrolytes with ionic surfactants is studied by turbidimetry and electron micrography, and a multilayer structure is observed only at the mole ratio of PVS:CTAB=2∶1 with a spacing of about 25A.
Abstract: The interaction of polyelectrolytes with ionic surfactants is studied by turbidimetry and electron micrography. The turbidity of the mixed solution of PVS (poly(vinyl sulfate)) and CTAB (cetyltrimethylammonium bromide) showed a sharp maximum at the mole ratio of 1∶1, indicating quantitative binding between PVS and CTAB. A multilayer structure was observed on the electron micrograph only at the mole ratio of PVS:CTAB=2∶1 with a spacing of about 25A. At the mole ratio of PVS:CTAB=1∶1, a single strand structure was observed. The system of ionene polymer (3,4)
$$\left( {\begin{array}{*{20}c} + \\ {\text{N}} \\ \end{array} {\text{CH}}_{\text{2}} )_3 - \begin{array}{*{20}c} + \\ {\text{N}} \\ \end{array} {\text{CH}}_{\text{2}} )4} \right)$$
-SDS (sodium lauryl sulfate) forms a multilayer structure at the equivalent ratio of 1∶1 with a spacing of 20A.
TL;DR: In this paper, the glass transition temperature of amorphous and fractionated poly(ethylene terephthalate) has been measured by differential scanning calorimetry and the flex energy of the chain is evaluated by the Gibbs-Di Marzio theory with a value of 1483 cal/mol.
Abstract: The glass transition temperature of amorphous and fractionated poly(ethylene terephthalate) has been measured by differential scanning calorimetry. The application of the Fox-Flory equation for the range of molecular weights between 37100 and 4500 gives the values of Tg∞=342.4 K and Kg=51200. The low value of Kg is interpreted by the free volume theory. The flex energy of the chain is evaluated by the Gibbs-Di Marzio theory with a value of 1483 cal/mol. These results are compared with those obtained by other authors for the poly(ethylene adipate) and the poly(diethylene terephthalate).
TL;DR: In this article, the mesophase formed at low temperature was studied by differential scanning calorimetry (DSC) and polarized light microscopy, which could explain the liquid crystalline behavior of these polyesters, particulary their transition temperatures and the mesphase width.
Abstract: New thermotropic Polyesters having mesogenic groups based on substituted hydroquinone units and highly flexible oligosiloxan spacer in the main chain, are synthesized and characterized. The mesophase formed at low temperature are studied by differential scanning calorimetry (DSC) and polarized light microscopy. The liquid crystalline behaviour of these polyesters, particulary their transition temperatures and the mesophase width could be explained on the basis of their structural features.
TL;DR: Comportement photoelastique de reseau ionise ou non par 5% de methacrylate de sodium, dans les melanges acetone eau as discussed by the authors.
Abstract: Comportement photoelastique de reseau ionise ou non par 5% de methacrylate de sodium, dans les melanges acetone eau
TL;DR: In this paper, the reaction of silanol groups on the surface of glass fiber with diisocyanates was investigated, and it was found that the effect of organometallic catalysts upon the reaction varied with their metal ions or their ester substituents.
Abstract: Reaction of silanol groups on the surface of glass fiber with diisocyanates were investigated. It was found that the effect of organometallic catalysts upon the reaction varied with their metal ions or their ester substituents. Then the addition reaction of isocyanate group on glass fiber surface, with amino acid was carried out successfully to prepare a glass fiber-amino acid adduct.
TL;DR: A kinetic study on propylene polymerization with the catalyst system of MgCl2-supported TiCl4 catalyst in conjunction with AlEt3 and PhCO2Et (EB) has been made to elucidate the role of EB which is known to increase stereospecificity of produced polypropylene.
Abstract: A kinetic study on propylene polymerization with the catalyst system of MgCl2-supported TiCl4 catalyst(MgCl2/TiCl4) in conjunction with AlEt3 and PhCO2Et (EB) has been made to elucidate the role of ethyl benzoate (EB) which is known to increase stereospecificity of produced polypropylene. It has been found that a part of added EB was fixed on the supported Ti catalyst and that EB modified the isotactic specific centers to increase the kp (iso) value. Thus the productivity of isotactic polymer and the molecular weight of the isotactic polymer(2·104(¯Mn) to 6·104 at 60°C) were increased.
TL;DR: In this paper, a model of junction network is used to calculate maximum attainable draw ratios (X) and corresponding values of tensile strength (F) for different conditions of polymer film and fiber forming.
Abstract: A model of junction network that is deformed upon drawing has been used to calculate maximum attainable draw ratios (X) and corresponding values of tensile strength (F) for different conditions of polymer film and fiber forming. Experimental data for melt-spun samples of polyethylene (PE), polycaproamide and polyoxymethylene and solution-cast films of polyvinylalcohol appeared to be in good agreement with calculated values. Considered also are methods for the increase of X and F due to polymer molecular weight enhancement in samples forming from “poor” solvent with subsequent orientation drawing under optimal conditions. Values of X=130–230 and those of F = 7 GPa with a Young's modulus E=144 and sonic modulus Es=200 GPa, approximating theoretical, have been obtained for monofilaments of PE with m.w. 2.106.
TL;DR: In this article, the PTC activity of a number of polyethyleneglycols (PEGs) fixed on the macroporous glycidyl methacrylate copolymer (0.09 − 0.7 mmol PEG/g) was tested and compared with that of dissolved PEGs.
Abstract: By using a model reaction between sodium phenoxide and n-butyl bromide, the PTC activity of a number of polyethyleneglycols (PEG) fixed on the macroporous glycidyl methacrylate copolymer (0.09–0.7 mmol PEG/g) was tested and compared with that of dissolved polyethyleneglycols. Both systems are catalytically active; 1 mmole of fixed PEG raises the reactivity 168 times, and in solution 139 times compared with the uncatalyzed reaction. In the case of immobilization, PEG 2000 and higher are catalytically somewhat more active than in solution; the lower activity of immobilized PEG s with mol. wt up to 1550 is interpreted by the lower mobility of parts of the chain due to immobilization. The rise in catalytic activity with the molecular mass of fixed PEG is in accord with their higher sorption ability towards cations of alkali metals.
TL;DR: In this paper, two-dimensional auto correlation with ω 1-scaling NMR spectroscopy is used to observe connectivities between triad and tetrad1H NMR resonances.
Abstract: FOCSY two-dimensional J-resolved NMR spectroscopy is used to resolve1H NMR resonances corresponding to triad and tetrad configurations of poly(vinyl alcohol). Two-dimensional auto correlation with ω1-scaling NMR spectroscopy is used to observe connectivities between triad and tetrad1H NMR resonances. Comparison of these connectivities to the necessary compositional relationships at triad-tetrad level leads to absolute configurational assignments for the1H NMR spectrum of poly(vinyl alcohol).
TL;DR: In this article, it was shown that the cross-linked PVA gels exhibit an increase of swelling properties with the reticulation degree, up to a certain limit, and then more advanced reticulations induce a decrease in swelling capacities.
Abstract: Unlike usual polyhydroxilic packing materials for liquid chromatography based on cross-linked agarose, CL-amylose and CL-dextrans (Sephadex), the cross-linked PVA gels exhibit an increase of swelling properties with the reticulation degree, up to a certain limit. Afterwards more advanced reticulation degrees induce a decrease in swelling capacities just as in case of other cross-linked polyhydroxilic polymers. This abnormal behaviour of CL-PVA was supposed as being due to the interchain hydrogen associations. IR spectra, X-ray data and 8 M urea treatments strongly supported our supposition pointing out a maximum association by hydrogen bonds in CL-PVA gels with a reduced degree of reticulation.