WO2000078831A1

WO2000078831A1 - Ethylene and/or alpha-olefin/vinyl or vinylidene aromatic interpolymer compositions

Info

Publication number: WO2000078831A1
Application number: PCT/US2000/015525
Authority: WO
Inventors: Stephen F. Hahn; Oscar D. Redwine; Ravi B. Shankar; Francis J. Timmers
Original assignee: The Dow Chemical Company
Priority date: 1999-06-22
Filing date: 2000-06-05
Publication date: 2000-12-28
Also published as: AR026131A1; JP2003503513A; CN1357014A; TW527366B; CA2384373A1; KR20020013933A; EP1200491A1; AU5324300A

Abstract

The present invention pertains to an interpolymer comprising; (1) from 5 to 85 mol percent of polymer units derived from one or more vinyl or vinylidene aromatic monomers, (2) from 15 to 95 mol percent of polymer units derived from at least one of ethylene and/or a C3-20 alpha-olefin; and (3) from 0 to 20 mol percent of polymer units derived from one or more of ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2); and wherein said interpolymer contains detectable vinyl or vinylidene aromatic monomer triads.

Description

ETHYLENE AND/OR ALPHA-OLEFIN/VINYL OR VINYLIDENE AROMATIC INTERPOLYMER COMPOSITIONS

The present invention relates to compositions comprising interpolymers of vinyl or vinylidene aromatic monomers with ethylene and/or one or more alpha-olefin monomers. The catalyst used to prepare these interpolymers, [(4,5-methylene- phenanthrenyl) (tert-butylamido) dimethylsilane] dimethyl titanium, has a remarkably high reactivity towards vinyl or vinylidene aromatic monomers. The resulting interpolymers, contain successive vinyl or vinylidene aromatic monomer insertions and thus can have vinyl or vinylidene aromatic monomer incorporation in excess of 65 mole percent.

Until recently, the copolymerization of ethylene and vinyl or vinylidene aromatic monomers was not a commercially viable process using the traditional Ziegler alpha- olefin polymerization catalysts based on Ti (III) and Ti (IV) halides. Most earlier attempts to prepare copolymers of vinyl aromatic monomers and alpha-olefins, in particular copolymers of styrene and ethylene, with such catalysts have either failed to obtain substantial incorporation of the vinyl aromatic monomer or else have achieved polymers of low molecular weight. In Polymer Bulletin, 20, 237-241(1988) there is disclosed a copolymer of styrene and ethylene containing 1 mole percent styrene incorporated therein. The reported polymer yield was 8.3 x 10^"4 grams of polymer per micromole titanium employed. However, with the advent of the metallocene based olefm polymerization catalysts, and in particular the constrained geometry type catalysts, it is now possible to copolymerize ethylene and other alpha-olefins with styrene and other vinyl or vinylidene aromatic monomers to provide interpolymers.

Copolymers of ethylene and styrene including materials with more than 50 mole percent styrene incorporation have been reported using an ansa metallocene catalyst as disclosed by Arai, T.; Ohtsu, T.; Suzuki, S. in Macromolecular Rapid Commun. 1998, and Polym. Prepr., 1998, 39(1), 220-221.

In addition, U.S. Patent No. 5,703,187 describes "pseudo random" ethylene styrene interpolymers characterized by a unique monomer distribution in which successive head-to-tail styrene monomer insertions are not observed that is no SS diads or SSS triads. Except for the absence of sequential head-to-tail styrene monomer insertions, the styrene distribution in interpolymers is still found to be well dispersed hence the term "pseudo-random". A particular distinguishing feature of pseudo-random copolymers was the fact that all phenyl or bulky hindering groups substituted on the polymer backbone are separated by 2 or more methylene units. During the addition polymerization reaction, if a vinyl or vinylidene aromatic monomer is inserted into the growing polymer chain, the next monomer inserted must be ethylene or a vinyl or vinylidene aromatic monomers which is inserted in an inverted fashion (where inverted is taken to mean a 2,1 insertion where a normal insertion is taken to be 1,2, however it is understood by those skilled in the art that the opposite can be true and would not change the description or properties of the interpolymers of the present invention). After an inverted vinyl or vinylidene aromatic monomer insertion, the next monomer must be ethylene, as the insertion of another vinyl or vinylidene aromatic monomer at this point would place the hindering substituent closer together than the minimum separation as described above. A consequence of these polymerization kinetics is that the catalysts used did not homopolymerize styrene to any appreciable extent, while a mixture of ethylene and styrene is rapidly polymerized and may give high styrene content (up to 50 mole percent styrene) copolymers. A direct consequence of this monomer distribution was that the practical upper limit of styrene incorporation was approximately 50 mole percent or 79 weight percent styrene.

WO 98/0999 describes the "substantially random" ethylene styrene interpolymers which, while including the aforementioned the pseudo random interpolymers, also included interpolymers prepared using specific metallocene polymerization catalysts. Use of these specific metallocene polymerization catalysts resulted in the formation of interpolymers characterized by a unique monomer distribution. In this distribution, although most of the polymer chains are pseudo random in styrene distribution, a small amount of sequences involving two head-to-tail vinyl aromatic monomer insertions preceded and followed by at least one ethylene insertion were observed. That is an ethylene/styrene/styrene/ethylene tetrad, ESSE, wherein the styrene monomer insertions of said tetrads occur exclusively in a 1,2 manner). Thus these specific substantially random ethylene/styrene interpolymers contain similar peaks in the NMR spectrum as the pseudo random ethylene/styrene interpolymers, but also are characterized by additional signals with intensities appearing in the chemical shift range 43.70-44.25 ppm. As a result of this unique monomer distribution, the upper limit of styrene incorporation in the substantially random ethylene styrene interpolymers was raised to approximately 65 mole percent or 87.5 weight percent styrene.

We have now suprisingly discovered that that the catalyst, [(4,5-methylene- phenanthrenyl) (tert-butylamido) dimethylsilane] dimethyl titanium, has a remarkably high reactivity towards vinyl or vinylidene aromatic monomers in their polymerization with ethylene and/or one or more alpha-olefin monomers, and results in the preparation of new interpolymers which include, in the case of ethylene/styrene interpolymers, both SSS and higher (for example SSSS, SSSSS etc) sequences. As a result of this increased reactivity of the catalyst, the resulting interpolymers are able to exhibit upper limits to their vinyl or vinylidene aromatic monomer contents in excess of 65 mol percent. The present invention pertains to an interpolymer comprising;

(1) from 5 to 85 mol percent of polymer units derived from at least one vinyl or vinylidene aromatic monomer,

(2) from 15 to 95 mol percent of polymer units derived from at least one of ethylene and/or a C₃.₂₀ alpha-olefin; and

(3) from 0 to 20 mol percent of polymer units derived from one or more of ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2); and wherein said interpolymer contains detectable vinyl or vinylidene aromatic monomer triads.

All references herein to elements or metals belonging to a certain Group refer to the Periodic Table of the Elements published and copyrighted by CRC Press, Inc., 1989. Also any reference to the Group or Groups shall be to the Group or Groups as reflected in this Periodic Table of the Elements using the IUPAC system for numbering groups. Any numerical values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component or a value of a process variable such as, for example, temperature, pressure, time is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that values such as 15 to 85, 22 to 68, 43 to 51 , 30 to 32 etc. are expressly enumerated in this specification. For values which are less than one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 as appropriate. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner.

The term "interpolymer" is used herein to indicate a polymer wherein at least two different monomers are polymerized to make the interpolymer. This includes copolymers, terpolymers, etc.

The term "detectable vinyl or vinylidene aromatic monomer triads" is used herein to indicate a sequence of three successive vinyl or vinylidene aromatic insertions in the interpolymer. In the case of an ethylene/styrene inteφolymer this would correspond to an -SSS- triad. When any atactic polystyrene impurity is separated out from the polymer, these triads are detectable by the presence of a peak in the ¹³C NMR spectrum which occurs at a chemical shift corresponding to the methine carbons in the polymer backbone of an ethylene/styrene interpolymer at 44.6 ppm (ESSSE) Such triads may also be a part of a longer sequence of vinyl or vinylidene aromatic insertions insertions such as SSSS tetrads, SSSSS pentads. Additional peaks corresponding to the following insertions may also be present in the inteφolymers; 46.0 ppm (ESE), 43.75 (ESSE), and 41.6 ppm (>3 successive S insertions). It is understood by one skilled in the art that for such insertions involving a vinyl or vinylidene aromatic monomer other than styrene, and an alpha-olefin other than ethylene, then the inteφolymer will give rise to similar ¹³C NMR peaks but with slightly different chemical shifts.

The inteφolymers of the present invention are prepared using the catalyst , [(4,5- methylene-phenanthrenyl) (tert-butylamido) dimethylsilane] dimethyl titanium.

We have suφrisingly discovered that that this catalyst has a remarkably high reactivity towards vinyl or vinylidene aromatic monomers in their polymerization with

-A- ethylene and/or one or more alpha-olefin monomers. This results in the preparation of new inteφolymers which include, in the case of ethylene/styrene inteφolymers, both SSS and higher (for example SSSS, SSSSS etc) sequences. As a result of the increased reactivity of the catalyst, the resulting inteφolymers are able to exhibit upper limits to vinyl or vinylidene aromatic monomer contents in excess of 65 mol percent.

One method of preparation of the inteφolymers of the present invention includes polymerizing a mixture of polymerizable monomers in the presence of [(4,5-methylene- phenanthrenyl) (tert-butylamido) dimethylsilanejdimethyl titanium and a suitable activating compound. Using this catalyst, the inteφolymers of the present invention can be prepared by the processes described in EP-A-0,416,815 by James C. Stevens et al. and US Patent No. 5,703,187 by Francis J. Timmers, both of which are incoφorated herein by reference in their entirety. Preferred operating conditions for such polymerization reactions are pressures from atmospheric up to 3000 atmospheres and temperatures from - 50°C to 200°C. Polymerizations and unreacted monomer removal at temperatures above the autopolymerization temperature of the respective monomers may result in formation of some amounts of homopolymer polymerization products resulting from free radical polymerization. While preparing the inteφolymers of the present invention, an amount of atactic vinyl or vinylidene aromatic homopolymer may be formed due to homopolymerization of the vinyl aromatic monomer at elevated temperatures. The presence of vinyl aromatic homopolymer is in general not detrimental for the puφoses of the present invention and can be tolerated. The vinyl aromatic homopolymer may be separated from the inteφolymer, if desired, by extraction techniques such as liquid chromatography or selective precipitation from solution with a non solvent for either the inteφolymer or the vinyl or vinylidene aromatic homopolymer. The inteφolymers of the present invention include inteφolymers prepared by polymerizing i) ethylene and/or one or more alpha-olefin monomers and ii) one or more vinyl or vinylidene aromatic monomers and optionally iii) other polymerizable ethylenically unsaturated monomer(s).

Suitable alpha-olefins include for example, alpha-olefins containing from 3 to 20, preferably from 3 to 12, more preferably from 3 to 8 carbon atoms. Particularly suitable are ethylene, propylene,_.butene-l, 4-methyl-l-pentene, hexene-1 or octene-1 or ethylene in combination with one or more of propylene, butene-1, 4-methyl-l-pentene, hexene-1 or octene-1. These alpha-olefins do not contain an aromatic moiety.

Other optional polymerizable ethylenically unsaturated monomer(s) include norbornene and C,.₁₀ alkyl or C_6.10 aryl substituted norbornenes, with an exemplary inteφolymers being ethylene/styrene/norbornene and ethylene/styrene/ethylidene norbornene.

Suitable vinyl or vinylidene aromatic monomers, which can be employed to prepare the inteφolymers, include, for example, those represented by the following formula:

Ar I (CH₂)_n

R^l _ c = C(R )₂ wherein R¹ is selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to 4 carbon atoms, preferably hydrogen or methyl; each R² is independently selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to 4 carbon atoms, preferably hydrogen or methyl; Ar is a phenyl group or a phenyl group substituted with from 1 to 5 substituents selected from the group consisting of halo, C_M-alkyl, and C_M-haloalkyl; and n has a value from zero to 4, preferably from zero to 2, most preferably zero. Exemplary vinyl aromatic monomers include styrene, vinyl toluene, alpha-methylstyrene, t-butyl styrene, chlorostyrene, including all isomers of these compounds. Particularly suitable such monomers include styrene and lower alkyl- or halogen-substituted derivatives thereof. Preferred monomers include styrene, alpha-methyl styrene, the lower alkyl- (C, - C₄) or phenyl-ring substituted derivatives of styrene, such as for example, ortho-, meta-, and para-methylstyrene, the ring halogenated styrenes, para-vinyl toluene or mixtures thereof. A more preferred vinyl aromatic monomer is styrene. The resulting inteφolymers may be modified by typical grafting, hydrogenation, functionalizing, or other reactions well known to those skilled in the art. The polymers may be readily sulfonated, using processes described in WO 99/20691, the entire contents of which are herein incoφorated by reference, chlorinated or otherwise functionalized, as described in copending US Application No. 09/244,921 filed on February 4^th, 1999 by R. E. Drumright et al., the entire contents of which are herein incoφorated by reference. The compositions of the present invention may also be modified by various cross-linking processes. These include, but are not limited to peroxide-, silane-, sulfur-, radiation-, or azide-based cure systems. A full description of the various cross-linking technologies is described in U.S. Patent 5,869,591 and 5977,271, the entire contents of both of which are herein incoφorated by reference. Dual cure systems, which use a combination of heat, moisture cure, and radiation steps, may be effectively employed. For instance, it may be desirable to employ peroxide crosslinking agents in conjunction with silane crosslinking agents, peroxide crosslinking agents in conjunction with radiation, sulfur-containing crosslinking agents in conjunction with silane crosslinking agents, etc. Dual cure systems are disclosed and claimed in U. S. Patent 5,911,940, the entire contents of which is incoφorated herein by reference.

Additives such as antioxidants (for example, hindered phenols such as, for example, Irganox® 1010 a registered trademark of Ciba Geigy), phosphites (for example, Irgafos® 168 a registered trademark of Ciba Geigy), U.V. stabilizers, cling additives (for example, polyisobutylene), slip agents (such as erucamide and/or stearamide), antiblock additives, colorants, pigments, tackifiers, flame retardants, coupling agents, fillers, plastcizers can also be included in the compositions of the present invention.

Also included as a potential component in the compositions of the present invention are various organic and inorganic fillers. Representative examples of such fillers include organic and inorganic fibers such as those made from asbestos, boron, graphite, ceramic, glass, metals (such as stainless steel) or polymers (such as aramid fibers) talc, carbon black, carbon fibers, calcium carbonate, alumina trihydrate, glass fibers, marble dust, cement dust, clay, feldspar, silica or glass, fumed silica, alumina, magnesium oxide, magnesium hydroxide, antimony oxide, zinc oxide, barium sulfate, aluminum silicate, ammonium polyphosphate, calcium silicate, titanium dioxide, titanates, aluminum nitride, B₂O₃, nickel powder or chalk.

Other representative organic or inorganic fiber or mineral fillers include carbonates such as barium, calcium or magnesium carbonate; borates such as magnesium or zinc borate, fluorides such as calcium or sodium aluminum fluoride; hydroxides such as aluminum hydroxide; metals such as aluminum, bronze, lead or zinc; oxides such as aluminum, antimony, magnesium or zinc oxide, or silicon or titanium dioxide; silicates such as asbestos, mica, clay (kaolin or calcined kaolin), calcium silicate, feldspar, glass (ground or flaked glass or hollow glass spheres or microspheres or beads, whiskers or filaments), nepheline, perlite, pyrophyllite, talc or wollastonite; sulfates such as barium or calcium sulfate; metal sulfides; cellulose, in forms such as wood or shell flour; calcium terephthalate; and liquid crystals. Mixtures of more than one such filler may be used as well.

The fillers may also be used in conjunction with a coupling agent and/or initiator selected from organic peroxides, silanes, titanates, zirconates, multi-functional vinyl compounds, organic azides, and mixtures thereof. Other additives include the hindered amine stabilizers. Such stabilizers include hindered triazines such as substituted triazines and reaction products of triazines. Suitable reaction products include the reaction product of triazine with, for example, diamines and/ or cycloaliphatic compounds such as cyclohexane. A particularly suitable hindered amine stabilizer includes the reaction product of 1, 3-propanediamine, N,N"-l,2-ethanediylbis-, cyclohexane and peroxidized N-butyl-2,2,6,6-tetramethyl-4-piperidinamine-2,4,6- trichloro-l,3,5-triazine which ismade commercially by Ciba-Geigy and has the name "CG-116 having CAS Reg No. : 191680-81-6.

These additives are employed in functionally equivalent amounts known to those skilled in the art. For example, the amount of antioxidant employed is that amount which prevents the polymer or polymer blend from undergoing oxidation at the temperatures and environment employed during storage and ultimate use of the polymers. Such amount of antioxidants is usually in the range of from 0.01 to 10, preferably from 0.05 to 5, more preferably from 0.1 to 2 percent by weight based upon the weight of the polymer or polymer blend. Similarly, the amounts of any of the other enumerated additives are the functionally equivalent amounts such as the amount to render the polymer or polymer blend antiblocking, to produce the desired result, to provide the desired color from the colorant or pigment. Such additives can suitably be employed in the range of from 0.05 to 50, preferably from 0.1 to 35, more preferably from 0.2 to 20 percent by weight based upon the weight of the inteφolymer. Fillers may suitably be employed in the range 1-90 wt.percent.

The polymers of the present invention can be blended with additional polymers including but not limited to; other inteφolymers of different molecular weight and/or vinyl or vinylidene aromatic monomer content, substantially random inteφolymers vinyl and vinylidene halide polymers including but not limited to poly(vinyl chloride) and poly( vinylidene chloride), polyethylene, and other polyolefins including but not limited to LDPE, and HDPE, PP, homogeneous ethylene/alpha-olefin copolymers produced by metallocene catalysts, including but not limited to the substantially linear ethylene/alpha- olefin copolymers and heterogeneous and heterogeneous ethylene/alpha-olefin copolymers produced by Ziegler catalysts; styrenic polymers including but not limited to polystyrene, SBS copolymers, polyethers, polycarbonates, polyanilines, asphalt, or any combinations thereof. The inteφolymers of the present invention, or blends thereof, can be fabricated into various forms including but not limited to films, fibers, foams, sheets, injection molded articles, membranes, injection-blow molded articles and extruded profiles, and emulsions. Applications for the inteφolymers of the present invention, or blends thereof, include, but are not limited to, ignition resistant articles, pressure sensitive filmstock, coating compositions or paints, floor, ceiling and wall coverings, caφet backing, barriers, gaskets, caps and closures, and, with the addition of conductive additives such as carbon black, various conductive applications including electrical devices, conductor shields, insulation shields, and other wire and cable applications. Other applications include as compatibilizers in blends of polystyrene and ethylene and/or alpha-olefin homo- and copolymers. Also included are applications for the sulfonated derivatives including their use in fuel cell membranes, water absorbent applications and HVAC equipment.

Determining the composition of the ethylene/styrene inteφolymers of the present invention can be ambiguous using NMR methods of analysis. This ambiguity arises from the fact that the styrene triads and higher order styrene insertions have peaks in both the Η and ¹³C spectra that can not be distinguished from peaks of the ubiquitous amoφhous atactic polystyrene homopolymer (aPS) which is present in small amounts in the inteφolymers. However use of a liquid chromatography (LC) method using gradient solvent polarity allows separation of the inteφolymer from the aPS, and the retention time of the inteφolymer peak is indicative of its styrene content. The inteφolymer compositions of the present invention comprise from 5 to 85, preferably from 20 to 85, more preferably from 50 to 85 mole percent of at least one vinyl or vinyl or vinylidene aromatic monomer and from 15 to 95, preferably from 15 to 80, more preferably from 15 to 50 mole percent of ethylene and/or at least one aliphatic alpha-olefin having from 3 to 20 carbon atoms.

The melt index (I₂) of the inteφolymer of the present invention is greater than 0.05, preferably of from 0.5 to 200, more preferably of from 0.5 to 100 g/10 min. The molecular weight distribution (M M of the inteφolymers of the present invention is from 1.5 to 20, preferably of from 1.8 to 10, more preferably of from 2 to 5.

The inteφolymer compositions of the present invention contain detectable vinyl aromatic monomer triads. In the case of an ethylene/styrene inteφolymer this would correspond to an -SSS- triad. Such triads may also be a part of a longer sequence of vinyl or vinylidene aromatic insertions insertions such as SSSS tetrads, SSSSS pentads. When any atactic polystyrene impurity is separated out from the polymer, these triads are detectable by the presence of a peak in the ¹³C NMR which occurs at a chemical shift corresponding to the methine carbons in the polymer backbone of an ethylene/styrene inteφolymer at 44.6 ppm (ESSSE).

The following examples are illustrative of the invention, but are not to be construed as to limiting the scope thereof in any manner.

EXAMPLES Test Methods

The molecular weight of the polymer compositions of the present invention is conveniently indicated using Gel Permeation Chromatography using both UV and Refractive Index detectors.

In order to determine the ¹³C NMR chemical shifts of the inteφolymers of the present invention, the following procedures and conditions are employed. A five to ten weight percent polymer solution is prepared in a mixture consisting of 50 volume percent l,l,2,2-tetrachloroethane-d2 and 50 volume percent 0.10 molar chromium tris(acetylacetonate) in 1,2,4-trichlorobenzene. NMR spectra are acquired at 130°C using an inverse gated decoupling sequence, a 90°-pulse width and a pulse delay of five seconds or more. The spectra are referenced to the isolated methylene signal of the polymer assigned at 30.000 ppm.

Materials Testing Polymer samples were formed into the shapes required for physical property determination by compression molding at 150°C using a ten minute preheat, 3 minute compression at 10000 pounds force, and immediate cool down.

Differential Scanning Calorimetry (DSC) analysis of this polymer was performed under a nitrogen atmosphere at a heating rate of 5°C/minute using a DuPont Instruments 910 Differential Scanning Calorimeter. All samples were taken through two heating cycles (to remove the effects of previous heat history) and data are reported for the second scan in all cases.

Micro-tensile testing was performed using compression molded micro-tensile bars as per ASTM D638 testing protocol. The samples were pulled using an Instron 4507 Series instrument at a cross-head speed of 0.1 inches/minute and a 224.8 lbf load cell at room temperature.

Plain-strain fracture toughness, compact tension single-edge notch geometry samples were compression molded into 1" by 1" by 1/8" squares. These squares were machined to provide a side notch and holes for attachment to the testing apparatus. A pre- crack was formed in each sample by cooling with liquid nitrogen and cracking with a razor blade and hammer. Fracture toughness testing was performed using an Instron 8501 instrument at a cross-head speed of 0.02 in/min with a 224.8 lbf load cell. Dynamic mechanical spectroscopy was performed on a rectangular bar, which was compression molded at 100°C. Temperature sweeps ranging from -100°C to 150°C were performed at a set frequency of 1 rad/sec with an auto-strain function set by the DMS instrument. Density was measured using a helium pycnometer. Rockwell hardness was assessed using ASTM D785-93. L.C. Analysis.

Between 0.100 and 0.102 grams of polymer were weighed into a 30 ml vial. 10 ml of THF was added. The vial was capped and placed on a heated shaker so as to dissolve the sample. The temperature of the heated shaker was 65° C. After dissolution, about 1 ml of the solution was transferred to an HP 1090 LC auto-injector vial. A Hewlett-Packard 1090 LC (serial number 2541A00700) with a diode array detector was used for the collection of all chromatographic data. Signals were collected at 254 nm and 400 nm. The chromatographic data were processed using Grams386 and Excel software. Two columns were used to determine the styrene contents of the resins by liquid chromatography. Use of either column initially involved determination of the atactic polystyrene content (which peak was clearly discernible). This value was then subtracted from the total styrene content of the sample as determined by 13C N.M.R to give the wtpercent copolymerized styrene. A calibration curve of copolymerized styrene v. retention time (at the 50^lh percentile of the chromatogram peak) was then constructed and the resulting fit was then applied to all new samples. This analysis was performed using two types of column.

The first of these was a C18 column was obtained from Alltech: Spherisorb ODS II 5 micron, 250 x 4.60 mm. There was a guard column on the Cl 8 column. It was an RP 8.5 micron. Below are the instrumental conditions used on the HP 1090 with the C18 column).

The second and best column of the two was a nitro column obtained from Phenomenex: Nucleosil 5 NO2 250 x 4.60 mm, 5 micron, serial number 243745. There was a guard column on the nitro column. It was a Phenomenex Nucleosil 5 NO2 30 x 4.6 mm, 5 micron 100 angstrom, serial number 243747G. Below are the instrumental conditions used on the HP 1090 with the Nitro2 method (nitro column).

The regression equation used to determine the styrene content on this column was: [sty] wtpercent = -84.89 + 10.98 * retention time (mins)

Preparation of the Examples 1 - 6 of the Inteφolymers of the Present Invention. 1) Preparation of Catalyst General

Syntheses and manipulations were carried out in an inert atmosphere (argon) glove box. Solvents were purchased from Aldrich. Liquid reagents and solvents were first saturated with nitrogen and then dried by passage through activated alumina prior to use as disclosed by Pangborn, A.B.; Giardello, M.A.; Grubbs, R.H.; Rosen, R.K.; Timmers, F.J. in Organometallics, 1996, 15, 1518- 1520 . Deuterated benzene was dried over sodium/potassium alloy and filtered prior to use. Methylene phenanthrene was purchased from Lancaster. NMR spectra of ligands and metal complexes were recorded on a Varian 300 MHz NMR spectrometer at ambient conditions. ¹³C NMR spectra of the copolymers were recorded on a Bruker 600 MHz spectrometer. Synthesis of Lithium Methylenephenanthrenide

To 4,5-methylenephenanthrene (0.485 g, 2.55 mmol) in 50 mL of hexanes was added 1.6 M n-BuLi in hexanes (1.75 mL, 2.80 mmol). After one day of stirring at ambient conditions the solution appeared darker orange and a small amount of orange precipitated had formed. After 14 days much more precipitate had formed. This was isolated by decanting the supernatant from the solid which stuck to the inside walls of the flask. After drying under reduced pressure, 0.430 g were isolated (86percent yield). Volatile materials were removed from the supernatant to give an orange solid. Proton NMR analysis of this material showed it to be the starting methylenephenanthrene. Synthesis of (4,5-methylenephenanthrenyl)(tert-butylamino)dimethylsilane

To (tert-butylamino)dimethylsilyl chloride (0.436 g, 2.63 mmol) in 30 mL THF was added a cherry red solution of lithium methylenephenanthrenide (0.430 g, 2.19 mmol) in 20 mL THF. The solution was allowed to stir at ambient temperature overnight. The volatile materials were removed under reduced pressure. The solid residue was slurried in 10 mL hexanes and the volatile materials were removed under reduced pressure. The solid residue was extracted twice with a total of 30 mL hexanes. The extracts were filtered and the volatile materials were removed from the combined filtrates under reduced pressure to give 0.690 g (99percent yield) of an orange oil. The Η NMR spectrum was consistent with the desired product.

Synthesis of [(4,5-methylenephenanthrenyl)(tert-butylamido)dimethylsilane]titanium bis(dimethylamide)

A solution of the titanium tetrakis amide (0.484 g, 2.16 mmol) and (4,5- methylenephenanthrenyl)(tert-butylamino)dimethylsilane (0.690 g, 2.16 mmol) in 50 mL n-octane was heated and stirred at reflux. The course of the reaction was monitored by Η NMR spectroscopy by removing a small aliquot of the solution, removing the volatile materials under reduced pressure, and analyzing the residue in C6D6. Proton NMR analysis showed clean conversion to the desired product (for example 55percent conversion after ca. 48 hours reflux.) Several drops of titanium tetrakis amide were added periodically. After seven days at reflux, the reaction appeared not to be progressing past 82percent conversion. The volatile materials were removed from the cooled mixture under reduced pressure. The residue was dissolved in 20 L of hexanes and the resulting mixture was filtered. The volatile materials were removed from the filtrate under reduced pressure to give a dark powder (0.950 g). Proton NMR analysis of the product showed it to be a mixture of the desired product and the starting ligand, 82/18 mole percent, respectively (87 weight percent of the desired product).

Synthesis of [(4,5-methylenephenanthrenyl)(tert-butylamido)dimethylsilane]titanium dichloride

To the bis(amide)/ligand mixture isolated above (0.83 g, 1.83 mmol of the bis(amide)) issolved in 40 mL hexanes was added trimethylsilyl chloride (1.33 mL, 10.5 mmol). The solution was stirred at reflux for six hours. A small aliquot of the cooled solution was removed and the volatile materials were removed under reduced pressure. The residue was dissolved in C₆D₆ and analyzed by Η NMR spectroscopy. The spectrum showed very clean conversion to the monochloride-monoamide intermediate. An additional 1.3 mL of trimethylsilyl chloride was added and the sealed vessel was stirred at ambient temperature for eight days. The solution was then heated to reflux for six hours. The cooled solution was placed in the glove box freezer (-25 °C). The solids that formed were collected on a glass frit by vacuum filtration. The solid residue was washed once with cold hexanes (ca. 10 mL) and the solid was then dried under reduced pressure to give 0.516 g (65percent yield). Proton NMR analysis showed the material was consistent with very clean desired product.

Synthesis of [(4,5-methylenephenanthrenyl)(tertbutylamido)-dimethylsilane] dimethyltitanium

To the dichloride (0.516 g, 1.18 mmol) in 30 mL of THF was added 3.0 M methylmagnesium chloride (0.87 mL, 2.6 mmol) which resulted in an immediate color change. After standing overnight, the volatile materials were removed under reduced pressure. The solid residue was slurried in hexanes and the volatile materials were removed under reduced pressure. The residue was extracted several times with hexanes. The extracts were filtered and the volatile materials were removed from the combined filtrates under reduced pressure to give a bright orange powder, 0.392 g. Proton and ⁱ³C NMR analysis in C₆D₆ shows that the desired product was isolated as a 1 to 1 adduct with THF. Assuming a molecular weight was 467.6 g/mol, the isolated yield was 71 percent. The THF adduct (0.345 g) was dissolved in 50 mL toluene and heated at reflux for six hours. A color change from orange to brown-yellow was observed. The volatile materials were removed under reduced pressure. Proton NMR analysis of the residue showed clean conversion to a new compound. 2.) Polymerization All transfers of solvents and solutions described below were accomplished using a gaseous pad of dry, purified nitrogen or argon. Gaseous feeds to the reactor were purified by passage through columns of A-204 alumina and Q5 reactant. Alumina was previously activated at 375°C with nitrogen and Q5 reactant was activated at 200°C with 5percent hydrogen in nitrogen. Manipulations of catalyst and cocatalyst (tris pentafluorophenyl borane) were carried out in an inert atmosphere glove box.

The semi-batch reactor polymerization was conducted in a two liter Parr reactor with an electrical heating jacket, internal seφentine coil for cooling, and a bottom drain valve. Pressures, temperatures and block valves were computer monitored and controlled. Isopar E and styrene were measured in a solvent shot tank fitted to a balance. The resulting solution was then added to the reactor from the solvent shot tank. The contents of the reactor were stirred at 1200 φm. Hydrogen was added by differential expansion (ca. 50 psi) from a 75 ml shot tank initially at 300 psig. The contents of the reactor were then heated to the desired run temperature (90°C) under the desired ethylene pressure. The catalyst, [(4,5-methylenephenanthrenyl)(tert-butylamido)dimethylsilane]- dimethyltitanium and cocatalyst, tris(pentafluorophenyl)borane, were combined in the glove box (as 0.0050 M solutions in toluene)and transferred from the glove box to the catalyst shot tank through 1/16 in (0.16 cm) tubing using toluene to aid in the transfer. The catalyst tank was then pressurized using nitrogen. After the contents of the reactor had stabilized at the desired run temperature, the catalyst solution was injected into the reactor via a dip tube. The temperature was maintained by allowing cold glycol to pass through the internal cooling coils. The reaction was allowed to proceed for the desired time with ethylene provided on demand. Additional injections of catalyst were prepared and added in the same manner during the course of the run.

The contents of the reactor were then expelled into a 4 liter nitrogen purged vessel and quenched with isopropyl alcohol and 100 mg of Irganox 1010 in toluene was added as an antioxidant. Volatile materials were removed from the polymers in a vacuum oven at 140°C overnight and cooled to 50°C prior to removal from the oven. Reactor conditions and polymerization data were given in Table I.

Table I: Reactor Conditions/Run Data

Polymer Characterization

An LC method using gradient solvent polarity was used to separate the inteφolymer from the aPS and the retention time of the inteφolymer peak was indicative of its styrene content. Shown in Table II were composition, apparent molecular weight (polystyrene standards) and density data for the polymers reported herein.

Table II: Polymer Composition, Molecular Weight and Density Data

A From LC data with nitro column. B From LC data with C 18 column. C From proton NMR data.

With the information that these copolymers contained aPS, the SSS triad peaks in their ¹³C NMR spectra could be assigned. A very small EEE triad peak indicated that the inteφolymers had very few and short ethylene sequences. These materials all display either low levels of crystallinity, or were amoφhous. As a result, the density of these polymers increases with increasing styrene content and approaches 1.06 g/cc, the density of aPS.

The molecular weight data shows that the catalyst can produce high molecular weight polymers. Since a dual detector was used in the GPC analysis, it was possible to examine the ratio of refractive index divided by UV response across the molecular weight range. This ratio was found not to change much indicating that the composition was relatively uniform across the entire molecular weight range; a slight increase in the styrene content at very low molecular weights was seen in all of the samples. This was consistent with the presence of aPS in these materials. Materials Properties The thermal transition data as determined by DSC were given in Table III. Table III Thermal Transitions (DSC)

A

B From LC data with C18 column. C From proton NMR data.

As expected, the Tg of these materials was found to increase with increasing styrene content. The last two entries, which were well beyond the composition range of earlier pseudo random materials, show that the Tg rapidly approaches that of aPS (ca. 100°C) as the styrene content approaches near 100 percent. It should also be noted that none of the materials showed a pronounced Tg due to aPS homopolymer. The LC data, however, show aPS in the isolated materials. The polymer with the highest crystallinity (the lowest styrene content 55 wt percent S) displayed a peak melting temperature near 120°C and a Tg near 32°C.

Micro-tensile testing and fracture toughness testing was performed to assess the mechanical properties of these materials, Table IV. Short term tensile analysis showed a relatively glassy response with a high modulus at low tensile stress and a relatively linear stress/strain relationship for all of the materials up to about 2percent strain. The Young's modulus for all of these materials was in the range of 350,000-430,000 psi (2.4-3 GPa). All of the materials underwent a ductile yield at relatively low strains, with the yield strain moving steadily to lower elongation with increasing styrene content. All of the polymers exhibited slight drawing past the yield point up to ultimate failure. Table IV Microtensile, Fracture Toughness and Hardness Data

Fracture toughness was measured using compact tension geometry samples. These experiments were designed to quantify the polymer's resistance to initiation and propagation of the crack with respect to an applied load. The test was performed on a compression-molded square of the polymer, which was notched, and a razor blade was used to produce a crack at the V of the notch. A tensile load was then applied to the sample in plane stress; the specimen prepared was ideally thick enough to prevent twisting out the plane of the applied load. The resultant relationship between load and displacement allows for determination of the instantaneous stress required to propagate the crack, known as the stress intensity factor Klc. It was also useful to define the energy required to extend the crack over a given unit area; this quantity was denoted Glc, (the fracture energy or critical strain-energy release rate) and it related to Klc by equation 1 :

G_lc = (K_lc ²/E)(l-₂) (1) where E was Young's modulus and is Poisson's ratio. Larger values of Klc and Glc mean increased fracture toughness.

Fracture toughness measurements did not show meaningful differences from sample to sample for the materials, which were tested. Table V gives the critical stress intensity factor (KIC) values for the four samples with the highest styrene content, and data obtained under the same test conditions for a high molecular weight free radically polymerized polystyrene homopolymer. The copolymers show considerably higher KIC and GIC values, and the load to yield and to break were considerably higher for the copolymers than for polystyrene homopolymer.

The improved toughness of these materials with respect to polystyrene may arise from the ability of the ethylene units incoφorated to induce a more ductile response to applied stress on the time scale of the fracture test.

Table V Fracture Toughness Data for ES Copolymers

A Calculated using the measured Young's modulus and a Poisson's ratio of 0.33 B Free radical aPS, Mn=l 14,720, Mw=282,970, Mw/Mn=2.47 C Calculated from Klc using published values for Young's modulus (3.1 GPa) and Poisson's ratio (0.33) for high molecular weight PS (Encyclopedia of Polymer Science and Engineering, Vol. 16, 2 nd Ed., John Wiley & Sons, 1989, pp. 1-246)

DMS analysis of the non-crystalline inteφolymers was performed to determine the position of the glass transition and to identify other transitions associated with these materials. The glass transition temperature and room sub-Tg storage modulus increase with increasing styrene content in the copolymer.

In the shear loss modulus (G") response of the non-crystalline ES copolymers , the glass transition temperatures for these materials were clearly observed, and a broad transition was seen between ca. -50°C and room temperature. In polystyrene, this transition has been attributed to backbone relaxation that accompanies phenyl ring dislocation.

The physical properties of the high styrene content inteφolymers of the present invention indicate have improved resistance to fracture. This suggests that these inteφolymers may provide unique utility in certain applications. The amoφhous inteφolymers at the highest styrene levels were transparent, so that these polymers may have utility in film applications and may be advantaged with respect to aPS due to their increased toughness. Furthermore, foam sheets of these new polymers may show better resiliency than aPS sheets and may perform better in applications where improved durability was required. These polymers might also be used to toughen aPS while retaining good transparency, if compositions can be found which display compatibility.

Claims

CLAIMS:

1. An inteφolymer comprising;

(1) from 5 to 85 mol percent of polymer units derived from at least one vinyl or vinylidene aromatic monomer, (2) from 15 to 95 mol percent of polymer units derived from at least one of ethylene and/or a C₃.₂₀ alpha-olefin; and (3) from 0 to 20 mol percent of polymer units derived from one or more of ethylenically unsaturated polymerizable. monomers other than those derived from (1) and (2); and wherein said inteφolymer contains detectable vinyl or vinylidene aromatic monomer triads.

2. The inteφolymer of Claim 1; wherein

(1) Component (1) comprises from 20 to 85 mol percent of polymer units derived from said vinyl or vinylidene aromatic monomer represented by the following formula;

Ar I (CH₂)_n

Rⁱ — C = C(R2)₂ wherein R¹ is selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to 4 carbon atoms; each R² is independently selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to 4 carbon atoms; Ar is a phenyl group or a phenyl group substituted with from 1 to 5 substituents selected from the group consisting of halo, C_M-alkyl, and C_M-haloalkyl; and n has a value from zero to 4; or

(2) from 15 to 80 mol percent of polymer units derived from ethylene and/or said alpha-olefin which comprises at least one of propylene, 4-methyl-l-pentene, butene-1, hexene-1 or octene-1; and

(3) said ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2) comprises norbornene, or a C ₀ alkyl or C₆.₁₀ aryl substituted norbornene.

3. The inteφolymer of Claim 1; wherein

(1) Component (1) comprises from 50 to 85 mol percent of polymer units derived from said vinyl aromatic monomer which comprises styrene, alpha-methyl styrene, ortho-, meta-, and para-methylstyrene, and the ring halogenated styrenes, or

(2) from 15 to 50 mol percent of polymer units derived from ethylene, or ethylene and said alpha-olefin, which comprises ethylene, or ethylene and at least one of propylene, 4-methyl-l-pentene, butene-1, hexene-1 or octene-1; and

(3) said ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2) is norbornene.

4. The inteφolymer of Claim 3; wherein Component (l)(a) is styrene; and Component (2) is ethylene.

5. The inteφolymer of Claim 3; wherein Component (l)(a) is styrene; and Component (2) is ethylene and at least one of propylene, 4-methyl-l-pentene, butene-1, hexene-1 or octene-1.

6. An inteφolymer prepared by polymerizing

(a) at least one vinyl or vinylidene aromatic monomer,

(b) at least one of ethylene and/or a C₃.₂₀ alpha-olefin; and

(c) optionally one or more of ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2); in the presence of a catalyst comprising [(4,5-methylene-phenanthrenyl) (tert- butylamido)dimethylsilane]dimethyl titanium.

7. The inteφolymer of Claim 6 wherein; (a) said vinyl or vinylidene aromatic monomer is represented by the following formula; Ar I (CH₂)_n

Rⁱ _ c = C(R2)₂

R¹ is selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to 4 carbon atoms; each R² is independently selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to 4 carbon atoms; Ar is a phenyl group or a phenyl group substituted with from 1 to 5 substituents selected from the group consisting of halo, C_M-alkyl, and C_M-haloalkyl; and n has a value from zero to 4; or (b) said alpha-olefin which comprises at least one of propylene, 4- methyl- 1 -pentene, butene- 1 , hexene- 1 or octene- 1 ; said ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2) comprises norbornene, or a C,.₁₀ alkyl or C₆.₁₀ aryl substituted norbornene.

8. The inteφolymer of Claim 7; wherein Component (a) is styrene; and Component (c) is ethylene.

9. The inteφolymer of Claim 7; wherein Component (a) is styrene; and Component (c) is ethylene and at least one of propylene, 4-methyl-l-pentene, butene-1, hexene-1 or octene-1.

10. A process for preparing an inteφolymer by polymerizing

(a) at least one vinyl or vinylidene aromatic monomer, or

(b) at least one of ethylene and/or a C₃.₂₀ alpha-olefin; and

(c) optionally one or more of ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2); in the presence of a catalyst comprising [(4,5-methylene-phenanthrenyl) (tert-butylamido) dimethylsilane] dimethyl titanium.

11. The process of Claim 10 wherein;

(a) said vinyl or vinylidene aromatic monomer is represented by the following formula;

Ar I

(CH₂)_n

Rⁱ _ C = C(R2)₂ R¹ is selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to 4 carbon atoms; each R² is independently selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to 4 carbon atoms; Ar is a phenyl group or a phenyl group substituted with from 1 to 5 substituents selected from the group consisting of halo, C_M-alkyl, and C -haloalkyl; and n has a value

(b) said alpha-olefin which comprises at least one of propylene, 4-methyl-l- pentene, butene-1, hexene-1 or octene-1 ;

(c) said ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2) if present comprises norbornene, or a C,.₁₀ alkyl or C_6. ₁₀ aryl substituted norbornene.

12. The process of Claim 11 wherein; wherein Component (a) is styrene; and Component (c) is ethylene.

13. The process of Claim 11 wherein Component (a) is styrene; and Component (c) is ethylene and at least one of propylene, 4-methyl-l-pentene, butene-1, hexene-1 or octene-1.

14. A blend comprising;

A) the inteφolymer of Claim 1; and

B) one or more additional polymer components.

15. The blend of claim 15 wherein said additional polymer, Component B, is selected from the group consisting of substantially random inteφolymers, vinyl and vinylidene halide, ethylene homopolymers, alpha-olefin homopolymers ethylene/alpha-olefin copolymers, styrenic polymers, polyethers, polycarbonates, polyanilines, asphalt, or any combinations thereof.

16. The transition metal complex, [(4,5-methylene-phenanthrenyl) (tert-butylamido) dimethylsilanejdimethyl titanium.

17. A catalyst composition comprising [(4,5-methylene-phenanthrenyl) (tert-butylamido) dimethylsilanejdimethyl titanium.