Abstract: Provided is a novel olefin polymer which is excellent in lightness and moldability, has high rigidity and yields molded products excellent in flexural elasticity. The olefin polymer includes a propylene initial polymerization product formed in the presence of an olefin polymerization catalyst which is a contact reaction product of an olefin polymerization solid catalyst component containing a titanium atom, a magnesium atom, a halogen atom and an internal electron donating compound, at least one organoaluminum compound selected from the compounds of the general formula (I), and a first external electron donating compound; and a polypropylene part formed of a propylene polymerization product formed in the presence of the olefin polymerization catalyst and a second external electron donating compound higher in adsorption to the surface of the olefin polymerization solid catalyst component than the first external electron donating compound.

Abstract: Copolymers of ethylene and ?-olefins having (a) a density (D) in the range 0.900-0.940 g/cm3, (b) a melt index MI2 (2.16 kg, 190° C.) in the range of 0.01-50 g/10 min, (c) a melt index MI2 (2.16 kg, 190° C.) and Dow Rheology Index (DRI) satisfying the equation [DRI/MI2]>2.65, and (d) a Dart Drop Impact (DDI) in g of a blown film having a thickness of 25 ?m produced from the copolymer satisfying the equation DDI?1900×{1?Exp [?750(D?0.908)2]}×{Exp [(0.919?D)/0.0045]}. The copolymers may be prepared using metallocene catalysis and are preferably prepared in multistage processes carried out in loop reactors in the slurry phase. The copolymers exhibit long chain branching as defined by Dow Rheology Index (DRI) and exhibit unexpected improvements in mechanical properties, in particular dart drop impact, when extruded into blown films.

Abstract: The present invention relates to a catalyst system, to a method of manufacturing this system, and also to uses of this system. The catalyst system of the invention is characterized in that it comprises molecules of a polymer having, at one of its ends or along the chain, one or more polar functional groups; a solvent, said solvent, due to the fact of said polar functional group of said polymer, provoking and maintaining, when said molecules of the polymer are introduced thereinto, an organization of said molecules of the polymer into aggregates, micelles or vesicles so that the polar functional groups of said polymer are located inside the aggregates, micelles or vesicles formed; and a catalyst activator and a catalyst trapped in said aggregates, micelles or vesicles of said polymer. The catalyst system of the present invention may be used, for example, for catalyzing a (co)polymerization of olefins.

Abstract: The present invention relates to a catalytic complex for olefin metathesis reactions, to a process for its preparation and to its use in olefin metathesis reactions, particularly in ring opening metathesis polymerisation (ROMP) reactions.

Abstract: The present application provides a process for polymerizing at least one olefin in the presence of a polymerization catalyst, including: (A) continuously introducing a first liquid with a transition metal compound, an organometallic compound, and a solvent and a second liquid into an emulsification stage, (B) continuously withdrawing the emulsion and directing it into a solidification stage to form a slurry with a solid polymerization catalyst component, (C) continuously recovering the solid polymerization catalyst component, (D) directing the solid polymerization catalyst component into a first prepolymerization stage with a monomer and a second liquid to form a slurry, (E) recovering a prepolymerized solid polymerization catalyst component, (F) continuously introducing the prepolymerized solid polymerization catalyst component into a second prepolymerization stage with an olefin monomer to form a prepolymerized catalyst, and (G) continuously withdrawing the prepolymerized catalyst and directing it into a su

Abstract: This invention relates to the field of olefin polymerization catalyst compositions, and methods for the polymerization and copolymerization of olefins, including polymerization methods using a supported catalyst composition. In one aspect, the present invention encompasses a catalyst composition comprising the contact product of a first metallocene compound, a second metallocene compound, at least one chemically-treated solid oxide, and at least one organoaluminum compound. The new resins were characterized by useful properties in impact, tear, adhesion, sealing, extruder motor loads and pressures at comparable melt index values, and neck-in and draw-down.

Abstract: [Object] To provide a propylene homopolymer suitable for capacitor films having high withstand voltage and a stretched film formed by stretching the propylene homopolymer. [Solution] A propylene homopolymer of the present invention for capacitors satisfies the following requirements (i) to (v) and (ix): (i) the MFR is 1 to 10 g/10 minutes; (ii) the meso pentad fraction (mmmm) measured by 13C-NMR is 0.940 to 0.995; (iii) the integrted amount of elution at 90° C. by CFC using o-dichlorobenzene is 0.5% by weight or less; (iv) the melting point measured using DSC is 152° C. or more; (v) the chlorine content is 2 ppm by weight or less; and (ix) in an elution temperature-elution volume curve measured by cross-fractionation chromatography (CFC) using o-dichlorobenzene, the maximum peak has a peak top temperature in the range of 105° C. to 130° C. and half width of 7.0° C. or less.

Abstract: Process for the preparation of monoimine compounds, wherein a dicarbonyl compound is reacted in an aliphatic, non-aromatic solvent with aniline. Monoimine compounds having electron-withdrawing substituents in the ortho position and unsymmetric bis(imino) compounds and unsymmetric iron complexes prepared therefrom and the use thereof in the polymerization of olefins.

Abstract: Specific iron complexes (A), a catalyst system for polymerization of olefins comprising at least one metal complex (A) and/or (A?), a prepolymerized catalyst system, the use of these catalyst systems for the polymerization of olefins, and a process for the preparation of polyolefins by polymerization or copolymerization of olefins in the presence of one of the described catalyst systems.

Abstract: Provided is an ?-olefin polymer having an excellent balance between a molecular weight and a melting point, which is a polymer of one or more kinds of ?-olefins having 20 to 40 carbon atoms, and which meets the following requirements (1) to (4): (1) the ?-olefin polymer has a molecular weight distribution (Mw/Mn) determined from its weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene measured by a GPC method of 2 or less, and has an Mw of 5,000 or less; (2) measurement of a melting point (Tm) of the ?-olefin polymer with DSC shows one melting peak, a melting heat absorption (AH) calculated from an area of the melting peak is 20 J/g or more, and the melting peak has a half value width of 10° C. or less; (3) when the Mw falls within a range of 1,000 to 5,000 and an average number of carbon atoms (Cn) of the ?-olefins falls within a range of 20 to 40, the Mw, the Cn, and the Tm measured with the DSC satisfy the relationship, 0.0025×Mw+(Cn×3.3812?29.5)?Tm?0.

Abstract: A rubber composition having (A) an elastomer component in which the primary elastomer constituent is an ethylene-propylene elastomer polymerized in the gas phase with a metallocene catalyst and having a molecular weight of at least about 250,000; (B) a silicon-modified olefinic elastomer in an amount of from about 5 to about 50 parts per hundred parts of the elastomer component; (C) ground mica in an amount of from about 2.5 to about 30 parts per hundred parts of the elastomer component; and (D) a peroxide curative. The composition may be used in a vibration isolator which may be used in a belt drive system.

Abstract: Disclosed herein are novel polymer-tethered ligands, metal complexes comprising these ligands, and the use of these complexes as chain transfer catalysts to control the molecular weight of oligomeric and polymeric materials produced in a radical polymerization process. The materials made by the processes disclosed herein have significantly reduced color, making them suitable for a wide range of color-critical end-uses, including automotive coatings.

Abstract: The present invention relates to a process for the production of propylene copolymers wherein in a first step an olefin polymerization catalyst comprising a solid catalyst component is subjected to a prepolymerization reaction in a prepolymerization reactor, in which propylene monomers are present in an amount of 98.0 to 99.9 mol % and further alpha-olefin monomers other than propylene are present in an amount of 0.1 to 2.0 mol %, based on the combined amount of propylene and further alpha-olefin monomers, so that a prepolymer is produced on the catalyst in an amount of 10 to 1000 g per g of the solid catalyst component, and in a second, subsequent step propylene and further alpha-olefin monomers other than propylene are copolymerized in the presence of the prepolymerized catalyst produced in the first step so that a propylene copolymer is obtained which contains at least 0.

Abstract: Monocyclopentadienyl complexes in which the cyclopentadienyl system bears at least one bridged keto, thioketo, imino or phosphino group, a catalyst system comprising at least one of the monocyclopentadienyl complexes and a process for preparing polyolefins by polymerization or copolymerization of olefins in the presence of the catalyst system.

Abstract: A synthesis process of trans-1,4-polyisoprene, using bulk precipitation polymerization of isoprene catalyzed by supported titanium catalyst TiCl4/MgCl2. The process includes prepolymerizing carried out in a prepolymerization reactor with an anchor agitator; polymerizing carried out in a polymerization reactor with a helical ribbon agitator; and devolatilizing and drying carried out in a vacuum rake dryer. Not only does the process require lower energy consumption and thus a lower production cost, but it also eliminates the emission of three wastes.

Abstract: A catalyst composition for polymerizing olefins to polymers having bimodal molecular weight distribution comprises two transition metal-containing metallocene compounds, a magnesium compound, an alcohol, an aluminum containing co-catalyst and a polymeric support. The transition metal in one of the metallocene compounds is zirconium and the transition metal in the second metallocene compound is selected from the group consisting of titanium, vanadium and hafnium. Polyolefin polymers made using the catalyst composition have broad molecular weight distributions and are useful in film and blow molding applications.

Abstract: Process for the gas-phase polymerization of one or more alpha-olefins in the presence of a catalyst system, the process comprising: contacting in a continuous way one or more of said alpha-olefins with said catalyst system in a prepolymerization reactor, wherein the reaction is carried out in a liquid medium at a temperature ranging from 23° to 50° C.; feeding in continuous the prepolymer obtained in step a) into a gas-phase reactor having interconnected polymerization zones, where the growing polymer particles flow upward through a first polymerization zone (riser) under fast fluidization or transport conditions, leave said riser and enter a second polymerization zone (downcomer) through which they flow downward under the action of gravity, leave said downcomer and are reintroduced into said riser; wherein the prepolymer obtained from step a) is continuously fed at a section of said riser characterized by an upwardly gas velocity higher than 3.0 m/s.

Abstract: The invention relates to sulfur-functionalized polymer gels and carbon gels, including aerogels, and such carbon gels containing platinum or metal nanoparticles. The platinum-containing gels may be useful as fuel-cell electrodes.

Abstract: The present invention relates to a method of polymerizing olefin containing the step of pre-polymerization. More precisely, according to the method of the present invention, the reaction speed and temperature are regulated for pre-polymerization of a catalyst and then the pre-polymerized catalyst is added for the polymerization of propylene. Propylene having an improved molecular weight distribution, hydrogen reactivity and tacticity is produced.

Abstract: The present invention relates to a method of polymerizing olefin containing the step of pre-polymerization. More precisely, according to the method of the present invention, the reaction speed and temperature are regulated for pre-polymerization of a catalyst and then the pre-polymerized catalyst is added for the polymerization of propylene. Propylene having an improved molecular weight distribution, hydrogen reactivity and tacticity is produced.

Abstract: The invention has an object to provide a catalyst for polymerizing or copolymerizing an ?-olefin, catalyst constituent thereof, and method of polymerizing ?-olefins with the catalyst, for production of ?-olefin polymers or copolymers with high hydrogen response, high polymarization reaction rate, high stereoregularity and excellent melt fluidity. The invention discloses a catalyst constituent of the catalyst for polymerizing or copolymerizing an ?-olefin, represented by Formula 37 or 38: Si(OR1)3(NR2R3)Formula 37 (where in Formula 37, R1 is a hydrocarbon group with 1 to 6 carbon atoms; R2 is a hydrocarbon group with 1 to 12 carbon atoms or hydrogen; and R3 is a hydrocarbon group with 1 to 12 carbon atoms) RNSi(OR1)3Formula 38 (where in Formula 38, R1 is a hydrocarbon group with 1 to 6 carbon atoms; and RN is a cyclicl amino group).

Abstract: A precision fragmentation assemblage is disclosed, along with precision fragmentation assemblage catalysts derivable therefrom. A method for the preparation of a precision fragmentation assemblage is also disclosed, along with a method for preparing precision fragmentation assemblage catalysts from precision fragmentation assemblages. A method is further disclosed for using precision fragmentation catalysts in the polymerization of olefins to produce polyolefins.

Abstract: This invention is based upon the discovery that a catalyst system which is comprised of (a) palladium or a palladium compound and (b) a fluorinated alcohol is effective for polymerizing norbornene-functional monomers into polynorbornene-functional polymers. It has been further discovered that this catalyst system is more effective in polymerizing certain norbornene-functional monomers that are difficult to polymerize, such as norbornene ester monomers, than prior art catalyst systems. The activity of the catalyst systems of this invention can be further improved with respect to polymerizing some monomers by including a Lewis acid and/or a ligand, such as a phosphine or a carbene, in the system. In any case, the catalyst systems of this invention offer the advantage of being soluble in a wide variety of solvents, relatively inexpensive, and capable of polymerizing many norbornene-functional monomers that are difficult to polymerize with conventional catalyst systems.

Abstract: Disclosed is a process for polymerizing olefins. The process comprises polymerizing one or more olefins with a single-site catalyst in two or more polymerization stages. The catalyst comprises a transition metal complex, an activator, and a hydroxyl functional polymer. The complex, the activator, or both are chemically bound to the hydroxyl functional polymer.

Abstract: A process for polymerizing one or more alpha-olefins of formula CH2?CHT wherein T is a hydrogen atom or a C1–C20 alkyl radical comprising the following steps: a) contacting in a continuous way one or more of said alpha olefins with a metallocene based catalyst system in a loop reactor, wherein: (i) the reaction is carried out in a liquid medium; (ii) the average residence time of the metallocene-based catalyst system is not more than 30 minutes; (iii) the temperature of the loop ranges from 25° to 70° C.; in order to obtain a polymerization degree ranging from 60 to 500 g per gram of catalyst system; b) feeding in continuous the prepolymerized metallocene-based catalyst system obtained in step a) into a polymerization reactor C) polymerizing one or more alpha-olefins, the same or different from the alpha olefins used in step a), in the presence of said prepolymerized metallocene-based catalyst system.

Abstract: There is provided a method for producing a polymer, which is characterized by polymerizing or copolymerizing an organic compound monomer or monomers accommodated in pores of a porous metal complex.

Abstract: The present invention provides a prepolymerized olefin polymerization catalyst and olefin polymerization method using the same. More particularly, the present invention provides a prepolymerized catalyst that is encapsulated with macromonomers produced by polymerizing olefin monomers with a vinyl-terminated polysiloxane compound in the presence of a solid titanium catalyst for olefin polymerization having been previously surface treated with silane compounds containing two or more vinyl groups, and a method for producing polyolefin having a high melt strength using the catalyst.

Abstract: Catalyst solid for olefin polymerization comprising A) at least one calcined hydrotalcite and B) at least one organic transition metal compound, and also a catalyst system comprising the catalyst solid, the use of the catalyst solid for the polymerization or copolymerization of olefins and a process for preparing polyolefins by polymerization or copolymerization of olefins in the presence of the catalyst solid.

Abstract: The present invention relates to a process for homopolymerization of ethylene or copolymerization of ethylene with alpha-olefins by contacting ethylene or ethylene and alpha-olefin with a catalyst composition comprising: (a) a solid catalyst precursor comprising at least one vanadium compound, at least one magnesium compound and a polymeric material or a solid catalyst precursor comprising at least one vanadium compound, at least one further transition metal compound and/or at least one alcohol, at least one magnesium compound and a polymeric material; and (b) a cocatalyst comprising an aluminum compound.

Abstract: The present invention relates to a catalyst system for preparing styrene polymer and a method of preparing styrene polymer using the same, more particularly to a catalyst system for preparing styrene polymer capable of preventing coagulation of polymer to the reactor by preventing gelation, offering high conversion ratio, simplifying polymer production and enabling product size control, and a method of preparing styrene polymer using the same.

Abstract: An olefin polymerization pre-catalyst, an activated catalyst and a process for preparing the catalysts are described herein. The pre-catalyst has the formula: wherein the groups M and R1–R4 are defined herein. The group R4 includes a solid-support.

Abstract: The present invention provides a supported catalyst comprising (A) a polymer (B) a supporter, (C) a transition metal compound, and optionally (D) (a) a compound which can form an ionic complex by the reaction with the transition metal compound or (b) a specific oxygen-containing compound, and (E) an alkylaluminum compound. The supported catalyst according to present invention, which has a high activity, can be used for preparing a styrenic polymer with a high syndiotacticity. The supported catalyst can be used in combination with a cocatalyst, preferably an alkyl aluminoxane.

Abstract: An olefin polymerization titanium catalyst. It comprises a titanium compound and an organoaluminium compound cocatalyst supported on a soluble polysulfone comprising free reactive sulfone groups. The molar ratio of titanium of aluminum is 1–10:200 and the weight ratio of titanium to polysulfone is 0.01–0.1:0.3–2.5. The process for preparing the catalyst comprises preparing a supported titanium compound by contacting a solution of a polysulfone in a halogenated or polar solvent with a titanium compound or a solution thereof in a halogenated or polar solvent in an inert atmosphere at a temperature between 10° C. and the boiling point of the solvent such that the weight ratio of titanium to polysulfone is 0.01–0.1:0.3–2.5. The supported titanium compound is mixed with an organoaluminium cocatalyst such that the molar ratio of titanium to aluminum is 1–10:200.

Abstract: Catalyst system for olefin polymerization comprising A) at least one calcined hydrotalcite, B) at least one organic transition metal compound, C) optionally one or more cation-forming compounds and D) at least one organic magnesium compound.

Abstract: Supported stereospecific catalysts and processes for the stereotactic propagation of a polymer chain derived from ethylenically unsaturated monomers such as the polymerization of propylene to produce syndiotactic polypropylene or isotactic polypropylene. The supported catalyst comprises a stereospecific metallocene catalyst component and a co-catalyst component comprising an alkylalumoxane. Both the metallocene catalyst component and the co-catalyst component are supported on a particulate polyamide support comprising spheroidical particles of a polyamide having an average diameter with the range of 5-60 microns, and a porosity permitting distribution of a portion of the co-catalyst within the pore volume of the polyamide particles while retaining a substantial portion on the surface of the particles. The polyamide support is characterized by relatively low surface area, specifically a surface area less than 20 square meters per gram.

Abstract: Disclosed herein is a polyolefin nanocomposite prepared by polymerizing an olefin monomer in a catalyst system comprising (1) a supported catalyst consisting of a polymer, a silicate clay mineral, and a transition metal compound, and cocatalyst, an alkyl aluminoxane.

Abstract: A solid metallocene-containing catalyst system of an organoaluminoxane, at least one metallocene having at least one olefinically unsaturated substituent and a polyolefin is disclosed. The polyolefin is formed from at least one olefin polymerized in the presence of a combination of a solution of the organoluminoxane in an aromatic liquid, the at least one metallocene, and an aliphatic liquid. The solid metallocene-containing catalyst system may also include one or more the particulate solids.

Abstract: A modified supported olefin polymerization catalyst modified by prepolymerization with an olefin or an olefin mixture different from the olefin or olefin mixture of the subsequent olefin polymerization. The polymerization catalyst is a metallocene, and the melting or softening point of the polyolefin made using the catalyst is at least 20° C. lower than that of the prepolymerized polyolefin.

Abstract: Olefin polymers produced using components of catalysts obtained by contacting a Ti compound of formula Ti(OR)n-yXy, where n is the valence of titanium and y is a number between 1 and n, with a pre-polymer having a porosity higher than 0.3 cc/g and containing from 0.5 to 100 g of polymer per g of solid catalyst component, the pre-polymer being obtained by (co)polymerizing an olefin or a diolefin in the presence of a catalyst comprising a Ti, V, Zr or Hf compound supported on a Mg dihalide having a mean crystallite dimension lower than 30 nm.

Abstract: The present invention provides a catalyst for olefin polymerization having high olefin polymerization activity without being accompanied by generation of an adhered polymer on the wall of a polymerization reactor and the wall of pipe line and generation of a blocking massive polymer, and capable of manufacturing an olefin polymer industrially and stably for a long period of time.

Abstract: A method of modifying a Ziegler-Natta type polyolefin catalyst comprises contacting the Ziegler-Natta catalyst with olefin monomer to form a prepolymerized catalyst. The prepolymerized catalyst can comprise a reduced number of catalyst particles having a size of 40 microns or less. The prepolymerized catalyst can be used in a polymerization process to produce polymer fluff particles with a reduced number of polymer fluff fines than the Ziegler-Natta type catalyst.

Abstract: Supported catalysts for the polymerization of olefins comprise the following components: (A) a porous organic support functionalised with groups having active hydrogen atoms; (B) an organo-metallic compound of aluminium containing heteroatoms selected from oxygen, nitrogen and sulphur; and (C) a compound of a transition metal selected from those of groups IVb, Vb or VIb of the Periodic Table of the Elements, containing ligands of the cyclopentadienyl type. These supported catalysts, obtainable in the form of spherical particles, can be used in the polymerization reaction of olefins either in liquid or in gas phase, thus producing polymers endowed with a controlled morphology and with a high bulk density.

Abstract: A method for carrying out homogenous polymerization reactions in a reactor, wherein monomers and/or prepolymers are fed (apportioned). In a first step, an initiator is optionally admixed with the monomer and/or prepolymer. In a second step, once viscosity is substantially higher, a solvent is added thereto and/or the monomer itself is partially evaporated, it is condensed externally and/or internally and fed back into the reactor.

Abstract: The present invention concerns high-stiffness polymer composition and a process for producing a polymer composition by nucleated with a polymeric nucleating agent containing vinyl compound units. The method comprises modifying a catalyst by polymerizing a vinyl compound in the presence of said catalyst and a strongly coordinating donor in a medium, which does not essentially dissolve the polymerized vinyl compound, and by continuing the polymerization of the vinyl compound until the concentration of unreacted vinyl compounds is less than about 0.5 wt-%. The thus obtained modified catalyst composition is used for polymerizing propylene optionally together with comonomers in the presence of said modified catalyst composition. Modification of the catalyst according to the present invention will reduce production costs and provide highly reliable catalyst activity and polymers of high stiffness.

Abstract: A process as disclosed for producing a low density polyethylene using a particle form polymerization process and a titanium-containing catalyst wherein the ratio of comonomer to ethylene is at least about 1:1 and the titanium-containing catalyst is a special catalyst which has been pretreated with an organometallic reducing agent.

Abstract: Spherical catalyst components for the polymerization of olefins of formula RCH═CHR, in which R is, independently, hydrogen or a hydrocarbon group with 1-10 carbon atoms, containing a homogeneous transition metal compound of formula MPx, in which M is a transition metal M of Groups 3 to 11 or the lanthanide or actinide Groups of the Periodic Table of the Elements (new IUPAC version); P is a ligand that is coordinated to the metal M and x is the valence of the metal M. The transition metal compound is dispersed in a solid hydrocarbon matrix having a melting point above 70° C.

Abstract: The present invention relates to a process for preparing a highly active metallocene catalyst supported on polymer bead for olefin polymerization, a metallocene catalyst prepared by the said process and a method for alkylene polymerization by employing the said catalyst. The process for preparing a highly active metallocene catalyst supported on polymer bead for olefin polymerization which comprises the steps of: dissolving divinylbenzene, vinylbenzylchloride, and an initiator in an organic solvent, mixing it with a suspension stabilizer of aqueous phase, and carrying out suspension-polymerization at the temperature of 40 to 80° C. to obtain polystyrene; swelling the polystyrene in dialcoholamine dissolved in an organic solvent at ambient temperature for 1 to 3 days, to give a polymer having a functional group of dialcoholamine; and, reacting the polymer with a metallocene compound (CpM*Cl3) dissolved in an organic solvent.

Abstract: An ethylene polymerization process is disclosed. The process uses a single-site catalyst that contains a boraaryl ligand. It comprises supporting the catalyst, forming a slurry of the supported catalyst in an organic solvent, mixing the catalyst slurry with trialkyl aluminum compound, and polymerizing ethylene in the presence of the trialkyl aluminum-treated catalyst slurry. The process gives polyethylene having a controlled long-chain-branch index.

Abstract: The invention relates to supported ligands and catalysts for use in the polymerization of olefinically unsaturated monomers such as vinylic monomers, comprising the use of a compound attached to support, the compound being capable of complexing with a transitional metal. Preferably the compound capable of complexing with a transition metal is a diimine such as a 1,4-diaza-1,3-butadiene, a 2-pyridinecarbaldehyde imine, an oxazolidone or a quinoline carbaldeyde. Preferably the catalysts are used in conjunction with an initiator comprising a homolytically cleavable bond with a halogen atom. The application also discloses processes for attaching ligands to supports, and processes for using the catalysts disclosed in the application.

Abstract: A polymer includes at least propylene as a first monomeric component, 1-pentene as a second monomeric component, and, as a third monomeric component, a third olefin. The third olefin has fewer than 5 carbon atoms, is linear and is not propylene, or has 5 carbon atoms and is branched, or has more than 5 carbon atoms and is linear or branched.