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Showing papers by "DSM published in 1985"


Journal ArticleDOI
TL;DR: Etude par chimisorption: Cu, Rh, Pt, Pd, Ni, Ru, XPS as mentioned in this paper ; etude par desorption a temperature programe de H 2 (pour Ni, Ir, Pt).
Abstract: Etude par chimisorption: Cu, Rh, Pt, Pd, Ni, Ru. Etude par chromatographie. Etude par desorption a temperature programmee de H 2 (pour Ni, Ir, Pt). Etude par XPS

253 citations


Journal ArticleDOI
TL;DR: This paper proposes a mechanism which accounts for both the results obtained in enzymatic lignin degradation studies and in studies involving active oxygen species, and the implication of this type of mechanism on the oxidative biodegradation of the natural lign in polymer is discussed.

174 citations


Journal ArticleDOI
TL;DR: Lignin degradation Single‐electron transfer Cα‐Cβ bond cleavage Phanerochaete chrysosporium Peroxidase compound I

111 citations


Journal ArticleDOI
C. G. Vonk1, A. P. Pijpers1
TL;DR: In this paper, the results of wide-angle x-ray scattering (WAXS) were obtained with the aid of high and low-density polyethylene and ethylene-vinyl acetate copolymers, and the results were reconciled by assuming that the WAXS crystallinities pertain to the cores of the crystalline lamellae.
Abstract: In this investigation on samples of high- and low-density polyethylene and ethylene-vinyl acetate copolymers, crystallinities ϕW and crystalline densities ρcW were obtained with the aid of wide-angle x-ray scattering (WAXS) methods. From small-angle x-ray scattering (SAXS) the following characteristics were obtained either directly or by combination with the WAXS data: values, or limiting values, of the crystallinity ϕS; crystal densities ρcS; thicknesses of the diffuse boundary layer; number-average thicknesses of the crystalline and amorphous layers; and both number and weight averages of the long periods. It was shown that a discrepancy between ϕS and ϕW cannot be attributed to the occurrence of large amorphous regions outside the regular stacks of lamellae; the data were reconciled by assuming that the WAXS crystallinities pertain to the cores of the crystalline lamellae, whereas part of the diffuse boundary layers is comprised in the values of ϕS. The ρcW and ρcS data of the nonlinear samples show systematic differences, which were attributed to partial incorporation of side groups in the crystalline regions at a concentration estimated to be of the order of 20–40% of the overall concentration. With increasing side-group concentration, the thickness of the core of the crystalline lamellae was found to approach the average length of the linear chain segments between side groups. On the basis of these observations a scheme for the crystallization of nonlinear polyethylene is proposed according to which a number of side groups is encapsulated by the growing crystal. The data can be explained by assuming that all chains, offered at a crystal face where growth takes place, crystallize directly, irrespective of whether the crystallizing stem carries a side group. Further crystallization would then proceed by chain folding at both ends of the first stem, until a noncrystallizable unit is met. In this scheme, allowance is made for about half the stems in the crystals to be connected by folds; this is required in view of the “overcrowding” effect. Finally, the effect of cooling rate and molecular weight on the thicknesses of the crystalline and amorphous layers is discussed, and differences between the amorphous densities of high-and low-density polyethylene are noted.

87 citations


Journal ArticleDOI
TL;DR: A wide range of analytical techniques (XRD, DTA/TGA, I.R., texture, SEM/TEM,13C,27Al,29Si MAS NMR) has been used to characterize intermediate products formed during the crystallization process of the zeolite Tetrapropylammonium ZSM-5 (TPA-ZSM-1).

81 citations


Journal ArticleDOI
PJ Piet Lemstra1, Rob Kirschbaum1
01 Aug 1985-Polymer
TL;DR: The distinction often made between the mass-produced commodity polymers and speciality polymers is less clearly defined, since with novel preparation techniques bulk polymers are now increasingly used in speciality applications as mentioned in this paper.

71 citations


Journal ArticleDOI
E. Roerdink1, J.M.M. Warnier1
01 Sep 1985-Polymer
TL;DR: In this paper, the preparation of poly(tetramethylene adipamide) (nylon-4.6) has been studied and a kinetic model is proposed that describes the prepolymerization by a second order amidation reaction with formation of pyrrolidine end-groups as a side reaction.

56 citations



Journal ArticleDOI
TL;DR: In this article, the fracture properties of kolin-filled polyethylene composites were investigated using torsion pendulum tests, tensile tests, and scanning electron microscopy and ESCA.
Abstract: Kaolin-filled polyethylene composites were prepared under different mixing conditions. Viscoelastic properties of specimens were measured by torsion pendulum tests. Fracture behaviour was studied by tensile tests, and fracture surfaces by scanning electron microscopy and ESCA. Fracture properties turned out to be strongly influenced by processing conditions and to correlate with the amount of undissolvable polyethylene bound to the filler surface. This bound layer has an appreciably lower heat of fusion than the unfilled polyethylene.

34 citations


Journal ArticleDOI
TL;DR: In this paper, a quantitative method of analysis for urea and ammonia is described, which is based on ion-pair high-performance liquid chromatography with on-line post-column derivatization on immobilized urease.

32 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of physical aging on viscoelastic behavior of heterogeneous amorphous polyblends of ABS and polycarbonate was studied by means of stress relaxation experiments at different temperatures.
Abstract: The influence of physical aging on viscoelastic behaviour of heterogeneous amorphous polyblends of ABS and polycarbonate was studied by means of stress relaxation experiments at different temperatures. The stress relaxation data of the constituent phases ABS and PC are found to be in agreement with the universal description of relaxation behaviour of amorphous polymers at the onset of the glass-rubber transition. The regimes where master curve construction by time-temperature and time-aging time superposition is permitted could be deduced for the thermorheologically complex polyblends. It is shown that the relaxation curves of the ABS/PC blends can be calculated by means of a quasi-elastic extension of the van der Poel-model using the stress relaxation data of the constituent phases and their volume fractions.

Book ChapterDOI
TL;DR: In this article, the free enthalpy of mixing in the concentrated region is made temperature and molar mass-dependent, and the analysis leads to the inclusion of improvements such as different contact numbers for molecules and repeat units, distinction between concentration regimes, dilute and concentrated in polymer.
Abstract: Various solution properties have been selected for testing the usefulness of the classical lattice model. The analysis leads to the inclusion of improvements such as different contact numbers for molecules and repeat units, distinction between concentration regimes, dilute and concentrated in polymer. The extensions of the simple model supply an adequate description of the data provided the free enthalpy of mixing in the concentrated region is made temperature- and molar mass-dependent. Part of the latter contribution can be attributed to the chains bending back on themselves. The other part is not easily accommodated in the model and might be related to free volume effects that have been left out of the present consideration. The resulting free enthalpy expression quantitatively covers independent data like osmotic pressure measurements by Krigbaum and binodals in near ternary systems by Hashizume et al.

Journal ArticleDOI
TL;DR: In this article, a method was presented for obtaining from the zeroth-order peak in small-angle x-ray scattering (SAXS) patterns the weight average of the thickness C of crystalline lamellae in polymers close to the melting point.
Abstract: A method is presented for obtaining from the zeroth-order peak in small-angle x-ray scattering (SAXS) patterns the weight average of the thickness C of crystalline lamellae in polymers close to the melting point. The method fails if a first-order peak can be discerned to be superimposed on the zeroth-order peak. The method was applied, together with the one described in Part I of this series for obtaining the number average of C, to three polyethylene samples of different side-group content which were heated to temperatures close to the melting point. While heating always causes an increasing number of lamellae to melt, a linear sample also shows pronounced thickening of the remaining lamellae. This effect, however, decreases with increasing side-group content, and is virtually absent in a vinyl acetate copolymer containing 53 side groups per 1000 C atoms. A qualitative explanation for the role of the side groups in limiting the crystal thickening processes is put forward. By comparing results obtained after isothermal annealing and during isothermal crystallization from the melt it is concluded that at temperatures close to the melting point the polymers approach a final state which no longer depends on the thermal history of the sample.

Patent
20 Mar 1985
TL;DR: In this paper, a process for preparing a polymer alloy based upon at least one polyamide polymer, and polyurethane polymer, polyurea polymer and polyisocyanurate polymer is described.
Abstract: The invention relates to a process for preparing a polymer alloy based upon at least one polyamide polymer, and at least one polymer of the group of polyurethane polymer, polyurea polymer and polyisocyanurate polymer. The invention further relates to a molded object comprising a polyamide polymer, and at least one polymer of the group of polyurethane polymer, polyurea polymer and polyisocyanurate polymer. The invention further comprises a reaction injection molded product composed of an alloy consisting of 1. at least one polymer of the group of a polyurethane polymer, polyurea polymer and polyiso-cyanurate polymer and 2. a polyamide polymer.

Journal ArticleDOI
TL;DR: In this article, a single integral constitutive equation with an integrand factorable into a time-dependent and a strain-dependent function has been shown to give a satisfactory description of the rheological properties of a LDPE melt in uniaxial extensional flow.
Abstract: It is shown that a single integral constitutive equation with an integrand factorable into a time-dependent and a strain-dependent function gives a satisfactory description of the rheological properties of a LDPE melt in uniaxial extensional flow. The time-dependent memory function obtained in simple shear has been inserted into the equation and the tensorial strain functions deduced from different types of tensile experiments coincide reasonably.

Patent
03 Aug 1985
TL;DR: In this article, the reaction product of an epoxidized fatty acid ester of a polyvalent alcohol and a monovalent carboxylic acid was used for linoleum manufacturing.
Abstract: Resin compositions comprising two resins A and B, wherein resin A consists of the reaction product of an epoxidized fatty acid ester of a polyvalent alcohol and a monovalent carboxylic acid and resin B consists of a carboxylic acid modified fatty acid ester of a polyvalent alcohol. The resins compositions are suitable for linoleum manufacture.

Journal ArticleDOI
01 Nov 1985
TL;DR: In this paper, the classic Flory-Huggins-Staverman theory for macromolecular systems can easily be extended so as to deal with lower consolute miscibility behaviour as such, as well as in combination with upper consolute misbehavior in the same system.
Abstract: Within its own scope the classic Flory-Huggins-Staverman theory for macromolecular systems can easily be extended so as to deal with lower consolute miscibility behaviour as such, as well as in combination with upper consolute miscibility in the same system. A further improvement is achieved if the different numbers of nearest-neighbour contacts the various repeat units and molecules can make are accounted for. Strong bimodality of lower consolute cloudpoint curves seems to call for the introduction of free-volume terms. Some consequences of such bulk mixture terms are discussed briefly.


Journal ArticleDOI
TL;DR: In this article, a lattice-gas model is used to correlate and predict the thermodynamic behavior of pure compounds and mixtures, and the predicted power of the model was tested by comparing predicted spinodals, G-L equilibria, S-L equilibrium, and molar volumes with experimental literature data.

Journal ArticleDOI
TL;DR: In this article, the retention of n-alkanoic acids and n-alkylamines on octyl-Sepharose was measured as a function of pH at a constant sodium chloride molality.

Patent
08 Jul 1985
TL;DR: In this article, the storende low profile-drift ungesattigter Polyesterharze, die als schwundvermindernden Zusatz gesattigte Polyester enthalten, lasst sich durch Thermoplastenzusatz unterdrucken.
Abstract: Die storende low-profile-Drift ungesattigter Polyesterharze, die als schwundvermindernden Zusatz gesattigte Polyester enthalten, lasst sich durch Thermoplastenzusatz unterdrucken.

Patent
20 Sep 1985
TL;DR: In this paper, the authors describe a mixture of resole resorcinol and formaldehyde as a thickener, in which a precondensate is used as a pre-processed thickener.
Abstract: The invention relates to thermosetting resin compositions, particularly moulding compounds, based on resole resin, thickener, glass fibre, fillers and if desired condensation catalysts and further usual additives, in which a precondensate of resorcinol and formaldehyde is used as a thickener.

Patent
16 Dec 1985
TL;DR: In this article, a process for polymerizing e-caprolactam to form a nylon-6 block copolymer is described, in which a reactant stream containing 41 caprolactams and a lactam magnesium halide is brought into polymerizing admixture.
Abstract: A process for polymerizing e-caprolactam to form a nylon-6 block copolymer in which a reactant stream containing. e-caprolactam, and a lactam polymerization initiator is brought into polymerizing admixture with a reactant stream containing 41-caprolactam and a lactam magnesium halide, wherein sufficient 2-oxo-1-pyrrolidinyl compound is added to the admixture either as 2-pyrrolidinone, 2-oxo-pyrrolidinyl magnesium halide or 2-oxo-1-pyrrolidinyl capped initiator compound to enhance the rate of polymerization of the e-caprolactam. The lactam polymerization initiator is a telechelic oligomer or polymer containing a backbone which provides elastomeric segments in the nylon-6 block copolymer, and attached to the backbone are activated initiator groups which initiate the polymerization of e-caprolactam in the presence of the lactam magnesium halide.

Journal ArticleDOI
TL;DR: In this article, a thorough characterisation of acrylate latices is possible based mainly on potentiometric titrations in aqueous and non-aqueous media and on spectrophotometry.
Abstract: In the characterisation of latices conductometry is the technique most commonly used. In this paper it is shown that a thorough characterisation of latices is possible based mainly on potentiometric titrations in aqueous and non-aqueous media and on spectrophotometry. Results obtained with these techniques in the study of acrylate latices prepared with nonylphenolpolyethyleneoxidesulphate as the emulsifier are presented. It is shown that this type of emulsifier is subjected to considerable hydrolysis during the emulsion polymerisation process.

Patent
05 Aug 1985
TL;DR: In this paper, the reaction product of an epoxidized fatty acid ester of a polyvalent alcohol and a monovalent carboxylic acid was used for linoleum manufacture.
Abstract: Resin compositions comprising two resins A and B, wherein resin A consists of the reaction product of an epoxidized fatty acid ester of a polyvalent alcohol and a monovalent carboxylic acid and resin B consists of a carboxylic acid modified fatty acid ester of a polyva-lent alcohol.These resins compositions are suitable for linoleum manufacture.

Journal ArticleDOI
R. Koningsveld1
TL;DR: Breve revue des effets de distribution de la longueur de chaine, de la ramification, de the distribution chimique et du marquage au deuterium sur les equilibres de phases
Abstract: Breve revue des effets de distribution de la longueur de chaine, de la ramification, de la distribution chimique et du marquage au deuterium sur les equilibres de phases

Patent
06 Feb 1985
TL;DR: In this paper, a blow film on the basis of low-density polyethylene is prepared by extruding the molten polymer at melt temperatures at the die gap of below 135°C.
Abstract: Blown film on the basis of low-density polyethylene is prepared by extruding the molten polymer at melt temperatures at the die gap of below 135°C. Films that have been prepared this way have special orientation as a result of which good mechanical and optical properties are present. Oriented films are determined by X-ray diffraction analysis and have an intensity ratio of the 110 reflection band max./min. of at least 20, and an angle a between the average orientation direction of the polymer molecules and the film extrustion direction of at most 20°.

Journal ArticleDOI
TL;DR: In this paper, the deformation behavior of flat-headed darts was analyzed in terms of elasticity and plasticity, and it was concluded that the use of flatheaded darts results in strong shear loading, and most of the plastic deformation takes place by shear flow.
Abstract: The deformation behavior that results from falling weight impact testing with flat-headed darts is analyzed in terms of elasticity and plasticity. From a comparison of the time and temperature dependence of the yield stress that is observed during a falling weight test with the same dependences of the yield stress during simple shear tests, it is concluded that the use of flat-headed darts results in strong shear loading. Consequently most of the plastic deformation takes place by shear flow. Of practical interest is that this leads to a simple dependence of the yield stress during the impact test and the impact energy on the plate thickness. Furthermore, for a number of cases this result allows a direct conversion of temperature effects to time effects. In practice this means that it is possible to simulate the impact behavior at very high impact rates simply by performing impact tests at lower temperatures.

Journal ArticleDOI
TL;DR: In this article, the influence of the system on the composition of the crosslinked products as determined by HPLC is surprisingly small, and it is shown that formation of monosulfides is almost negligible under our conditions with all four vulcanization systems.
Abstract: The vulcanization of ENBH (C9H14), a model for vulcanization of EPDM containing ENB, was studied (140°, 1 h) using four different vulcanization systems (conventional, sulfur free, low-sulfur and high-sulfur). The influence of the system on the total yield of crosslinked products (C9H13—Sn—C9H13) is considerable, low-sulfur giving the lowest and high-sulfur giving the highest yield. The influence of the system on the composition of the crosslinked products as determined by HPLC is surprisingly small. By using 1H-NMR it was shown that formation of monosulfides is almost negligible under our conditions with all four vulcanization systems.

Book ChapterDOI
R. Koningsveld1, L. A. Kleintjens1
01 Jan 1985
TL;DR: In this article, the liquid-liquid equilibrium phase relations in polymer mixtures are analyzed in some detail with the aid of classic thermodynamical considerations, such as nearest neighbor contacts between the various repeat units, mutual influence of the flexibility of the polymer chains, non-uniform segment density, free volume, and chemical composition.
Abstract: Liquid-liquid equilibrium phase relations in polymer mixtures are analysed in some detail with the aid of classic thermodynamical considerations. Polymolecularity in the constituents causes cloudpoint curves not to represent coexisting phases and their extrema not to be identifyable with critical points. Such features should be taken into account when molecular theories are compared with experimental data. Multiple phase separations can be brought about by polymolecularity as well as by a special dependence of the interaction function on concentration. Molecular origins of the latter may be: 1) different numbers of nearest neighbour contacts between the various repeat units, 2) mutual influence of the flexibility of the polymer chains, 3) non uniform segment density, 4) free volume. Statistical copolymers have the extra complication of a distribution of chemical composition. The latter enhances the tendency towards multiple phase equilibrium, chemical composition and chain length governing details sensitively. In addition, differences in size between the repeat units appear to be of primary importance. Experimental methods suitable for thermodynamic measurements on the highly viscous mixtures in hand are briefly reviewed.