Showing papers by "DSM published in 1980"
DSM1
TL;DR: In this paper, the influence of the draw ratio on the mechanical and thermal properties of polyethylene fibres was investigated, and it was found that the tensile strength tended to approach an upper limit at high draw ratios.
Abstract: This paper deals with ultra-high-strength monofilaments of linear polyethylene that are produced by solution spinning and subsequent hot drawing at 120° C. The influence of the draw ratio on the mechanical and thermal properties of the fibres was investigated. Some salient features of a polyethylene filament with a draw ratio of 31.7 are: tensile strength at break=3.0 GPa, Young's modulus=90 GPa and DSC-melting point at a scan speed of 10° C min−1=145.5° C. The modulus was found to depend linearly on the draw ratio. The tensile strength tended, by contrast, to approach an upper limit at high draw ratios. Additional morphological and X-ray studies revealed an extremely good orientation of the macromolecules in the fibre direction of the highly drawn polyethylene monofilaments.
588 citations
DSM1
TL;DR: The morphology and structure of gels produced by quenching semidilute solutions of high molecular weight polyethylene in decalin is discussed in this article, where the drawing behavior of the dried gel films at room temperature and at 130 °C and the structural features of films drawn to ratios as high as 130 were examined with various microscopic techniques and wide-angle X-ray scattering.
Abstract: The morphology and structure of gels produced by quenching semidilute solutions of high molecular weight polyethylene\((\bar M_w = 1.5 - 3.5 \cdot 10^6 )\) in decalin is discussed. The drawing behavior of the dried gel films at room temperature and at 130 °C and the structural features of films drawn to ratios as high as 130 were examined with various microscopic techniques and wide-angle X-ray scattering.
125 citations
DSM1
TL;DR: In this article, the influence of the temperature on the drawing behavior of gel-fibres, which were obtained by spinning of a 2% w/w solution of high molecular weight polyethylene (M w = 1.1 × 10 6 ) in decalin, was studied in the range from 70 to 143°C.
123 citations
DSM1
TL;DR: In this paper, the straightforward two-component lattice gas treatment, shown by Trappeniers et al. to supply a qualitatively correct description of fluid phase behaviour, is applied here in an extended form so as to deal quantitatively with lowercritical demixing behaviour in alkane/polyethylene systems.
Abstract: The straightforward two-component lattice-gas treatment, shown byTrappeniers et al. to supply a qualitatively correct description of fluid phase behaviour, is applied here in an extended form so as to deal quantitatively with lowercritical demixing behaviour inn-alkane/polyethylene systems. Most of the parameters introduced have a clear physical meaning but, to achieve quantitative descriptions, some merely empirical parameters cannot be dispensed with. Their number is small, however, and the proposed procedure yields correct predictions of the location of lower critical miscibility gaps in temperature-concentration diagrams as well as their molar-mass- and pressure dependence. The parameters used are the interacting — surface areas of holes and sites occupied by either alkane or polymer segments (taken identical to the alkane units CH3 and CH2CH2), the molar hole volume (taken independent of mixture composition, pressure and temperature), the interaction energy between the structural units, and two empirical entropy correction parameters. No data on alkane/ polyethylene mixtures are needed and the treatment deals satisfactorily with pure substances and mixtures alike. Further improvements can be incorporated easily and application to more complicated polymer structures (long- and short chain branching) is well within the scope of the treatment.
107 citations
DSM1
TL;DR: In this article, the authors show that the pressure drop over a packed-bed reactor is lower than over a coiled open tubular reactor, and that for a given residence time and equal band-broadening values, the pressure drops over a PBR are lower than those of a COTR.
63 citations
DSM1
TL;DR: In this article, a survey of the control of commercial continuous and batch polymerization plants, by conventional means as well as with the help of processcomputers, PLCs and microcomputers is presented.
21 citations
DSM1
TL;DR: In this paper, the authors investigated the reaction rate of cyclohexanone oxime in the pH range 1.7 to 1.8 and found that the concentration of this adduct is negligibly small under all the conditions used here.
20 citations
DSM1
TL;DR: In this paper, a tensile strength of 3.2 GPa and an axial Young's modulus of 120 GPa were obtained by drawing high molecular weight polyethylene cast from a 1% polymer solution.
Abstract: The effective drawability of solution-cast or -spun high molecular weight polyethylene is enhanced significantly in comparison with an identical polymer sample that is crystallised from the melt.
The maximum attainable draw ratio, which primarily determines the final mechanical properties, increases continuously with decreasing initial polymer concentration in solution. A tensile strength of 3.2 GPa and an axial Young's modulus of 120 GPa could be obtained by drawing high molecular weight polyethylene cast from a 1% polymer solution. This phenomenon of increased drawability is discussed in terms of a reduced number of entanglements per macromolecule in solution-cast polyethylene.
19 citations
TL;DR: In this article, the compatibility of polymer mixtures from a thermodynamic standpoint is discussed from a temperatureodynamic standpoint, and deviations from the simple lattice theory (Flory-Huggins) show up sensitively in phase diagrams.
Abstract: The compatibility of polymer mixtures is discussed from a thermodynamic standpoint. Deviations from the simple lattice theory (Flory-Huggins) show up sensitively in phase diagrams. Possible molecular origins for such deviations are discussed. Experimental techniques that have recently been developed to deal with highly viscous mixtures are described.
15 citations
DSM1
TL;DR: In this article, a quasi ternary system composed of heterodisperse polyethylene, and the diluents hexamethylbenzene and adamantane is described.
Abstract: This paper describes the crystallisation and melting behaviour of the quasi ternary system composed of heterodisperse polyethylene, and the diluents hexamethylbenzene and adamantane. The simplified theory of melting point depression according to Flory and Huggins predicts a ternary eutectic point for this system, which was verified experimentally by differential scanning calorimetry. Morphological investigations revealed a complex rod-like eutectic microstructure with characteristic dimensions in the micron range1.
11 citations
Patent•
DSM1
Abstract: The invention provides unsaturated polyester compositions which can be cured to form flexible objects, which compositions comprise terminal 1,2-alkene dicarboxylic acid in an amount of 1 - 25, preferably 3 15 mol-percent, calculated on the total amount of dicarboxylic acid, and 1 - 8, preferably 2.5-6 mol-percent of the dicarboxylic acids in the chain of the polyester consists of trans-1,2-alkene dicarboxylic acid.
DSM1
TL;DR: In this paper, the thermal decomposition of diisopropyl peroxydicarbonate (IPP) in two solvents (chlorobenzene and tetrachloroethylene) was studied by [1H]NMR.
DSM1
Patent•
DSM1
TL;DR: In this paper, the authors provided novel curable unsaturated polyester compositions comprising a reactive copolymerizable monomer, a paraffin wax as an evaporation-reducing agent and as an adhesion promotor.
Abstract: The invention provides novel curable unsaturated polyester compositions comprising an unsaturated polyester, a reactive copolymerizable monomer, a paraffin wax as an evaporation-reducing agent and as an adhesion promotor a compound, containing 10-30 carbon atoms, of the class consisting of alkylaromatic, alkenylaromatic, alkylolaromatic compounds or an alcohol.
DSM1
TL;DR: In this article, low-angle laser light scattering measurements were performed on practically binary mixtures of standard polystyrenes dissolved in toluene, and second virial coefficients A2 were obtained as a function of the composition of the mixed polymer.
Abstract: Low-angle laser light scattering measurements were performed on practically binary mixtures of standard polystyrenes dissolved in toluene. Second virial coefficients A2 were obtained as a function of the composition of the mixed polymer. No solid evidence was found for the existence of maxima in A2 vs composition. Existing theories predict a maximum. The possible existence of minima such as reported by Suzuki5 could not be confirmed with the present system.
DSM1
TL;DR: In this article, the mixing rate of a special stirrer device was studied on various scales with different stirrer diameters and stirrer speeds; scaling-up procedures were developed, and a digital simulation model was set up to study the effects of the stirring parameters on mixing rate.
DSM1
TL;DR: In this paper, a phenomenological approach is presented that reduces permanent elastomers to thermorheologically simple materials, attributed to an unusual variation of the equilibrium modulus with temperature.
Abstract: Conventional time-temperature (t-T) superposition appears to be inappropriate to the viscoelastic behaviour of amorphous, peroxide cured EPDM networks. A phenomenological approach is presented that reduces these permanent elastomers to thermorheologically simple materials. Although the origin of the anomalous behaviour observed is not yet completely understood, it is attributed to an unusual variation of the equilibrium modulus with temperature.
Patent•
DSM1
TL;DR: A-methyl styrene, styrene and phenol in certain percentages, viz. 25 to 63, 35 to 73 and 2 to 15 percent by weight, respectively, are suitable for adhesives as discussed by the authors.
Abstract: Resins suitable for adhesives are based on a-methyl styrene, styrene and phenol in certain percentages, viz. 25 to 63, 35 to 73 and 2 to 15 percent by weight, respectively. Combinations of resin, ethylene vinyl acetate copolymer or thermoelastomer and optionally a wax or tackifying oil yield excellent adhesives, in particular hot-melt adhesives.
Patent•
DSM1
TL;DR: Solid hydrocarbon resins based on dicyclopentadiene, a vinylaromatic hydrocarbon and a benzene carrying 1 to 3 lower alkyl, hydroxyl or halogen substituents were used in adhesive formulations as mentioned in this paper.
Abstract: Solid hydrocarbon resins based on dicyclopentadiene, a vinylaromatic hydrocarbon and a benzene carrying 1 to 3 lower alkyl, hydroxyl or halogen substituents and the use of these resins in adhesive formulations.
DSM1
TL;DR: In this article, the momentary creep curve exhibits a universal shape over a rather large temperature range below Tg and above T β, and the authors proposed a formula for a momentary shear stress relaxation curve.
Abstract: Recently much progress has been made in describing the creep and stress relaxation behaviour of unfilled amorphous polymers in the glassy region with respect to the thermal and mechanical history.1–5 Struik3 demonstrated convincingly that the momentary creep curve exhibits a universal shape over a rather large temperature range below Tg and above T β . In accordance with these results, Booij and Palmen5 proposed a formula for the momentary shear stress relaxation curve. At small strains the curve locations on the time scale are governed only by the thermal history, but at larger stresses and strains also by the mechanical history.
DSM1
TL;DR: In this paper, an inspection unit has been designed with as principal component the automatic gel counting device of DSM - Enraf Nonius, with which some experience has been obtained in an ldpe plant, in which the unit was installed on line with the product stream.
DSM1
TL;DR: In this paper, it was shown that the nonlinear viscoelastic behaviour of polymer solutions and melts can be described by constitutive equations of the type proposed by M.C. Phillips.
Abstract: Recent investigations make it more and more clear that the nonlinear viscoelastic behaviour of polymer solutions and melts can be described by constitutive equations of the type proposed by M.C. Phillips
$$ p(t) = - pI + \int\limits_{{ - \infty }}^{t} {\mu (t - t')J(t - t')dt'} $$
(1)
where J(t-t’) is a generalised tensorial measure, not further specified, of the strain between time t and t’.