摘要:
Process for the alkylation of aromatic hydrocarbons by means of olefins containing from 2 to 8 carbon atoms, which comprises feeding the hydrocarbon, olefin, and possibly water, to the head of a fixed-bed reactor, operating with a “trickle flow” regime, containing at least one layer of a catalyst comprising a medium- or large-pore zeolite.
摘要:
The device of the present invention allows the pressure of a certain fluid to be reduced without reductions in the cross sectional area or organs in movement. The pressure reduction is obtained by passing the fluid to be depressurized, in sequence, through a plurality of pairs of steps. In the first step of each pair, part of the pressure energy of the fluid is converted to gravitational potential; in the second step the gravitational potential is converted into thermal energy, so as to prevent the reconversion of the same into pressure energy.
摘要:
Rubber-reinforced vinyl aromatic polymers having a strictly bimodal morphology, comprising from 55 to 90% by weight of a rigid polymeric matrix and from 10 to 45% by weight of a rubbery phase dispersed inside said rigid polymeric matrix, in the form of grafted and occluded particles and wherein said rubber particles consist of from 60 to 99% by weight of particles with a capsule or “core-shell” morphology and from 1 to 40% by weight of particles with a “salami” morphology, said percentages being measured on the basis of the weight of the rubber particles only.
摘要:
Device for the hot granulation of thermoplastic polymers, optionally expandable, which comprises: a) a die (1) containing a series of small plates (6), equipped with a series of extrusion holes, and a plurality of feeding ducts (3) situated inside the die body (2) in correspondence with the perforated small plates (6), lined with a material having a high thermal conductivity (4); b) a cutting chamber comprising a set of spraying nozzles (17) which create a jet of drops of a thermostat-regulating liquid for cooling the cut granules; c) a cutting system comprising a cutting plate (13) supporting a set of knives (15) arranged so that the cutting profile of the knife is radial with respect to the die.
摘要:
Rubber-reinforced vinyl aromatic polymers having a strictly bimodal morphology, comprising from 55 to 90% by weight of a rigid polymeric matrix and from 10 to 45% by weight of a rubbery phase dispersed inside said rigid polymeric matrix, in the form of grafted and occluded particles and wherein said rubber particles consist of from 60 to 99% by weight of particles with a capsule or “core-shell” morphology and from 1 to 40% by weight of particles with a “salami” morphology, said percentages being measured on the basis of the weight of the rubber particles only.
摘要:
A process for the continuous production of granules based on thermoplastic polymers includes at least one expandable agent and, optionally, other polymers or additives, among which inorganic pigments insoluble in the polymeric matrix, wherein a first main stream is prepared, in the molten state, and a second stream in the molten state, which englobes the additives and which is added to the first stream. The mixture is extruded through a die which is cooled by means of water jets from nozzles positioned behind the cutting blades.
摘要:
Vinyl aromatic (co) polymer reinforced with a rubber selected from a linear diene rubber (i) with a solution viscosity lower than 70 cPs; a partially radial diene rubber (ii), with a solution viscosity lower than 70 cPs; a three-chain diene rubber (iii) with a solution viscosity lower than 70 cPs; a blend of linear diene rubbers (i) and radial diene rubbers (iv) in a maximum ratio between them (i)/(iv) of between 99.5/0.5 and 85/15.
摘要:
Expandable particle composite material suitable for the preparation of expanded materials having a density lower than 40 g/l and a content of closed cells of at least 60%, including heterophase cavities and/or heterophase domains, whose matrix is a synthetic thermoplastic resin having at least 60% by weight of a vinyl aromatic polymer and in which an expanding system is contained, together with a heterogeneously distributed graphite material, having a graphitization degree, calculated by means of the Maire and Mering formula, of at least 0.2.
摘要:
Process for the production of granules of expandable thermoplastic polymers by means of extrusion, which comprises: i) melting the polymer in a single- or multi-screw extruder (2); ii) incorporating an expanding agent in the polymer in the molten state; iii) granulating the polymer thus obtained in a device comprising a die (111), containing a series of ducts (115) made of a material having a high thermal conductivity (114), a cutting chamber (118) containing a set of hydraulic nozzles and a cutting system equipped with a set of knives (215) with a cutting edge which is radial with respect to the surface of the die; iv) annealing the granules thus obtained; v) cooling the annealed granules to room temperature.
摘要:
Nanocomposite compositions based on expandable thermoplastic polymers which comprise: a) a polymeric matrix produced by the polymerization of a base comprising one or more polymerizable monomers; b) 1-10% by weight, calculated with respect to the polymer (a), of an expanding agent englobed in the polymeric matrix; c) 0.004-15% by weight, calculated with respect to the polymer (a), of an athermanous filler comprising nano-scaled graphene plates with a thickness (orthogonal to the graphene sheet) not greater than 150 nm, an average dimension (length, width, or diameter) not greater than 10 micrometers and a surface area>50 m2/g.