Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/42—Block-or graft-polymers containing polysiloxane sequences
  • C08G77/442—Block-or graft-polymers containing polysiloxane sequences containing vinyl polymer sequences
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/42—Introducing metal atoms or metal-containing groups

Definitions

• the present invention pertains to organic- inorganic composites and to methods for producing composites.
• This invention more particularly pertains to (1) reacted composites formed by the reaction of reactive sites of particular organic-inorganic composites or star polymers, and a method for preparing ' those reacted composites; and (2) particular organic- inorganic composites (hereinafter referred to as "TPSi(OR)3 composites") which are non-network in nature and have an inorganic core to which organic arms are attached by Si-O-metal bonds and have reactive sites and a method for preparing those composites.
• TPSi(OR)3 composites particular organic- inorganic composites
• U.S. Patent No. 4,933,391 discloses polymers which have the general formula T-P- E a - (CH2) n -Si (OR) 3, in which T is selected from an initiator fragment, each R is independently selected from hydrogen and straight chain alkyl radicals having up to about 8 carbon atoms, E is a benzyl group or substituted benzyl group having up to about 12 carbon atoms, a is a whole number having a value of 0 or 1, n is a whole number having a value of 0 to 4, and P is a poly(vinylaromatic) or poly(diene) chain.
• star polymer application which is incorporated herein by reference, teaches polymers (hereinafter referred to as “star polymers") produced using the end-capped polymers of U.S. Patent No. 4,933,391.
• TPS ⁇ (OR) 3 composites, TPESi (OR) 3 composites, star polymers and other similar organic- inorganic composites are also referred to collectively herein as "TP-organo-silanes” .
• Timothy E. Long and Larry W. Kelts are co-inventors herein.
• This invention and the inventions disclosed m the above-identifled patent and application are commonly assigned. The following art also relates to the application.
• Antonen, U.S. 3,655,598 discloses use of trialkoxysilyl difunctional polybutadiene oligomers which are co-condense ⁇ with Si-OH functional resins to form a network which is insoluble.
• Taylor, U.S. 3,817,911 makes composites by a simultaneous syntnesis of an organic polymer and a metal oxide precursor .
• the system is a physical blend.
• T is an initiator fragment
• P is poly(diene) or poly(vinylaromatic)
• E is benzyl having up to about 12 carbons
• a is 0 or 1
• n is an integer from 0 to 4
• POLYCOND is a partially condensed metal polycondensate having metal atoms selected from silicon, zirconium, titanium, aluminum, lead, boron, and tin
• zl is an ether link to another subunit
• z2 is an ether link to the polycondensate
• R 1 is selected fro -H and alkyls having from 1 to 4 carbons
• M is a metal selected from silicon, zirconium, titanium, aluminum, lead, boron and tin or is carbon
• R2 is alkyl or arylalkyl having a molecular
• ether link refers- to -O- linkages to carbons or to metal atoms. It is an advantageous effect of some embodiments of the invention to provide improved organic-inorganic composites, improved reacted composites and improved methods for producing composites which can provide varied ⁇ l, ⁇ 2, and T-- * reactivities.
• the reacted composite of the invention is a macromolecule in which two different sets of "arms" are joined to a metal condensate "core".
• One of the sets of arms is a polymer.
• the other set can be another polymer or a small molecule.
• both sets of arms are present in large numbers and are not present on a random basis or on the basis of a competition between components in a single reaction.
• the reacted composite of the invention incorporates primary and secondary subunits.
• the total number of subunits in a macromolecule of the reacted composite of the invention is from 3 to 50.
• the primary subunits have the general formula
• T is an initiator fragment.
• P is a poly(vinylaromatic) or poly(diene) chain.
• E is a benzyl group or a substituted benzyl group having up to about 12 carbon atoms.
• a is 0 or 1.
• n is an integer having a value from 0 to 4.
• the moiety T-P-E a - (CH2)n ⁇ of the primary subunit represents a "primary arm" of the reacted composite.
• Each primary arm is directly bonded to a silicon atom, referred to herein collectively as primary arm silicon atoms or primary arm metal atoms.
• POLYCOND is a partially condensed metal polycondensate having metal atoms selected from the group consisting of silicon, zirconium, titanium, aluminum, lead, boron, and tin.
• the partial condensation of the metal polycondensate means that in addition to metal condensation bonds having the general formula M-OM, in which each M is a metal, the polycondensate also includes metal non-condensation bonds having the general formula, M-OR, in which M is a metal and R is selected from hydrogen and lower alkyl groups of up to about four carbon atoms.
• R! is selected from the group consisting of - H and alkyls having from 1 to 4 carbon atoms.
• Zl is an ether link to a primary subunit or an ether link to a secondary subunit.
• z2 is an ether link to the partially condensed metal polycondensate.
• M is a metal selected from the group consisting of silicon, zirconium, titanium, aluminum, lead, boron and tin or is carbon.
• R is alkyl or arylalkyl and has a total molecular weight less than 1,000,000. R is not the same as the T-P-E a - (CH2)n _ of the primary subunit. R 2 represents the "secondary arm" of the reacted composite. Each R 2 is directly bonded to a metal atom, referred to collectively herein as secondary arm metal atoms.
• Each ml, m 2 , and n_3 is selected from integers from 0 to 3.
• ml + m is an integer from 1 to 3.
• ml + ir2 + m3 is equal to 3.
• m4 + 6 is an integer from 1 to the valence of M - 1.
• m 4 + m5 + m ⁇ + m 7 is equal to the valence of M.
• the "core” of the reacted composite (and the TPSi(OR)3 composites discussed below) represents the
• inorganic portions that is, all portions except the arms: the silicon and other metal atoms and their ether linkages and hydroxyl and alkoxy substituents.
• the primary subunits of the reacted composites of the invention are contributed by TP- organo-silane reactants which have primary moieties represented by the general formula )_1 T—P—E a -(CH 2 )
• the TP-organo- silane reactants have arms and a core.
• the arms have the general formula T-P-E a - (CH2)n _ and correspond to the primary arms of the reacted composites.
• the core like the core of the reacted composites, represents the remaining portions of the macromolecule: the silicon atoms and their ether linkages and hydroxyl and alkoxy substituents.
• the core of a TP-organo-silane reactant differs from the core of a reacted composite of the invention in that the TP-organo-silane reactant lacks secondary arm metal atoms.
• the reactant corresponds to the "star polymers" of U.S. patent application No. 555,505. If ml is not 0, then the reactant is described herein as a "organic- inorganic composite" .
• the reacted composites are prepared using novel organic-inorganic composites identified herein as "TPSi(OR)3 composites".
• the arms have the general formula T-P-, in which T is an initiator fragment and P is a poly(vinylaromatic) or poly(diene) chain.
• T is an initiator fragment
• P is a poly(vinylaromatic) or poly(diene) chain.
• Each polymer arm has a molecular weight of from about 1000 to about 100,000, and the average number of arms bonded to the core is from about 3 to about 50 or more.
• the core has a ratio of metal condensation bonds to the total number of possible metal condensation bonds within the range of from about 0.5 to about 0.9.
• the core has a metal content in which the ratio of moles of silicon contributed by the primary arms, that is, primary arm silicon atoms, to the total moles of metal in the core is within the range of from about 0.25 to 1 to about 4 to 1.
• the core is about 5 to about 30 weight percent of the TPSi(OR)3 composite.
• TPSi (OR) 3 composites has the following two steps: reacting an end-capped polymer with acidic water to prepare a prehydrolyzed intermediate in which about 50 to about 100 percent of -OR groups are converted to -OH and reacting the intermediate with a hydrolyzable metal compound.
• the endcapped polymers of the first step have the general formula T-P-Si(OR)3 # in which the same designations have the same meanings as in previous structure formulas.
• These polymers are made by bonding an endcapping group to a polymeric chain previously formed by an anionic living polymerization.
• the living polymerization is conducted using an olefinic unsaturated monomer and a univalent anionic initiator.
• a univalent anionic initiator Preferably an alkyllithium, alkylsodium, or alkylpotassium initiator is used.
• Many unsaturated monomers containing carbon- to-carbon double bonds can be polymerized using anionic initiators to yield living polymers.
• These include conjugated and non-conjugated dienes and vinyl- substituted aromatic compounds.
• Some illustrative, but non-limiting examples of useful dienes include the conjugated dienes having up to about 18 carbons, such as 1, 3-butadiene, isoprene, 1, 3-pentadiene, 2-phenyl- 1, 3-butadiene, 1, 3-octadecene, and the like.
• vinyl substituted aryl monomers include styrene, alpha- methyl-styrene, 4-methylstyrene, 4-tert-butylstyrene, 4-decyclstyrene, alpha-methylstyrene, 2- vinylnaphthalene, 2-vinylpyridine, and other vinyl substituted aromatics having up to about 18 carbon atoms.
• the living polymers used as intermediates in this invention can be homopolymers, copolymers, or block copolymers. The living polymerization is conveniently carried out at a temperature of from about -85°C to about 120°C.
• the polymerization is also conveniently carried out in a liquid ether or an aliphatic hydrocarbon which does not react with the catalyst.
• Tetrahydrofuran, cyclohexane, petroleum ether, and the like can be used.
• a reaction medium such as tetrahydrofuran has a tendency to react with material (s) used in the process, such an undesirable side reaction can be minimized in some instances by conducting the process at a low temperature.
• a reaction temperature as low as about -78°C or lower when tetrahydrofuran is employed as the reaction medium.
• the metal terminated polymer have a polymeric chain with a molecular weight in the range of from about 500 to about 1,000,000, more preferably from about 1,000 to about 100,000 and that the metal used be a univalent metal such as lithium, sodium, or potassium.
• a suitable functionalization (endcapping) reagent Several criteria must be met for the selection of a suitable functionalization (endcapping) reagent. First, an electrophilic site for direct deactivation of the polymeric carbanion must be present in the molecule. Also, the reaction should be quantitative or nearly quantitative, in order to maximize the efficiency of subsequent formation of condensed products. In addition, the efficiency of the functionalization reaction should be characterizable by a variety of complimentary techniques, e.g. spectroscopic and chemical.
• endcapping agents are selected from those having the formula: Ra-Si(ORb)3 .
• Ra is a reactive center for nucleophilic attack by the univalent metal carbanion.
• R can be a halogen radical selected from fluoride, chloride, bromide, and iodide. Ra can also be a halo (lower alkyl)- moiety.
• Rb is an alkyl radical of up to 8 carbon atoms.
• endcapping agents useful in this invention are halotrialkoxysilanes including fluoro, chloro, and bromo substituted tri(methoxy, ethoxy, butoxy) silanes.
• the endcapping reaction can be carried out in the reaction medium in which the metal terminated polymer is formed.
• the reaction temperature is not critical. It has been conducted at -78°C in tetrahydrofuran and at 60°C in cyclohexane.
• the reaction can be conducted for a reaction time within the range of from about 0.25 to about 2.0 hours. Shorter and longer times can be used if desired.
• the endcapping reaction is preferably conducted using an excess (10-100 mole percent or more) of the endcapping agent. However, it is not necessary that an excess be used; an exact stoichiometry can be employed, if desired.
• the process is preferentially conducted at ambient or slightly elevated pressures e.g. 1 atmosphere to about 1.1 atmosphere. Such pressures are not critical, and higher pressures or vacuum can be used if desired.
• the end-capped polymers prepared by reacting the metal terminated polymers and above-described end ⁇ capping agents are soluble in a material such as tetrahydrofuran, dimethylformamide, dimethylacetamide, acrylonitrile, N-methylpyrollidone, sulfolane, dimethylsulfoxide, and the like.
• end-capped polymers produced as described above, are bonded to a metal polycondensate that is formed in situ from a hydrolyzable reactant MX n> M is selected from Si, Zr, Ti, Al, Pb, B, or Sn;
• X is a hydrolyzable group selected from halogen and alkoxy groups of one to about eight carbon atoms; and n is the metal valence.
• X and the R groups of the living polymers can be the same or can differ.
• the alkoxy groups on the end-capped polymers react in a sol-gel hydrolysis/condensation reaction at a slower rate than the hydrolyzable groups in MX n .
• the end-capped polymer is subjected to a prehydrolysis, which forms Si-OH groups available for condensation.
• the prehydrolyzed intermediate produced is then reacted with the hydrolyzable reactant, one or more materials having the formula MX n .
• R'Si(OR) 3 +3H 2 0 R'Si(OH) 3 +3ROH illustrates complete hydrolysis of a trialkoxysilane such as a trimethoxysilane or triethyoxysilane. As shown, for each mole equivalent of trialkoxysilane employed, three moles of water are required for complete hydrolysis (ignoring any water produced by condensation) . For the purposes of this application, certain terminology is employed to describe features of this invention. Thus, Si-OR and Si-OH bonds illustrated by equation (1) are termed "non- condensation bonds.” In such bonds, silicon is not linked through an oxygen bridge to another metal atom.
• bonds in which metal atoms are linked through an oxygen bridge to form M-O-M groups, wherein each metal atom M is alike or different and is selected from the metals represented by M as stated above, are called "metal condensation bonds.”
• An illustrative M-O-M group is an Si-O-Si group.
• An M-O-M group contains two metal condensation bonds.
• the reaction can be followed using 29si NMR analysis to determine the actual number of metal condensation bonds formed.
• the total possible condensation bonds that can be formed can be calculated from the moles of hydrolyzable metal compound times the number of replaceable groups in the molecule that can condense.
• the total possible metal condensation bonds is (number of moles) x 3.
• reaction conditions employed to conduct the prehydrolysis step in the process of this invention are not critical.
• the prehydrolysis is preferably conducted in an acidic medium for the preparation of other TP-organo-silanes, such as TPESi(OR)3 composites, the prehydrolysis for the preparation of TPSi(OR)3 composites is slow in an acidic medium. This is surprising since, as is known in the sol-gel art, hydrolysis is fast under acidic conditions (low pH) .
• the acidic medium also provides acid as catalyst for the condensation reaction, however, in the case of TPESi (OR) 3 composites the acid undesirably drives the reaction toward condensation. If there is an appreciable amount of condensation, then an appreciable amount of starting polymeric reactant will be transformed into a material with limited available sites for reaction with the MX n reactant, and the yield of desired product will be reduced.
• a reaction temperature is selected which gives a suitable reaction rate, and which does not cause an undesirable amount of condensation (of hydrolyzed functionalized polymer) . In general, one employs a reaction temperature within the range of from about -35°C to about 75°C.
• reaction temperature within the range of from about -20°C to about 60°C.
• condensation is usually faster with higher reaction temperatures.
• condensation of the prehydrolyzed intermediate can be objectionable, since it diminishes the ability of this intermediate to react with the MX n reactant employed in the second step of the process of this invention. Therefore, when selecting a reaction temperature, or a regime of reaction temperatures, one keeps in mind not only the desire to achieve a suitable hydrolysis reaction rate, but also the desire to refrain from producing an unacceptable amount, for example, greater than 50 percent, of undesired condensation product.
• reaction temperature or temperatures which "balances" (a) the rate of the desired prehydrolysis, with (b) the rate of the undesired condensation of the prehydrolyzed intermediate, so that hydrolysis is heavily favored, and any condensation is maintained within an acceptable amount.
• the reaction time is not a truly independent variable, but it is dependent at least to some extent on the other reaction conditions employed; for example, the reaction temperature, the inherent reactivity of the reactant, the efficiency of the catalyst employed, etc. In general, one employs a reaction time that strikes a favorable balance between the hydrolysis that is desired, and (undesired) condensation of the prehydrolyzed intermediate.
• reaction time can be selected with a limited amount of preliminary experimentation, especially if the reaction results are followed using 29si NMR as an experimental tool.
• a suitable prehydrolysis reaction time can be about one hour. Greater or lesser reaction times can be employed.
• reaction times for the prehydrolysis are generally in the range from about five minutes to about five hours. Reaction times somewhat outside this range can be used.
• the reaction pressure is not critical. In general, the prehydrolysis is conducted at ambient pressure; however, greater and lesser pressures can be used if desired. For example, one may wish to run the prehydrolysis at a reduced pressure to facilitate hydrolysis, e.g. when the hydrolysis by-product is a volatile species such as isobutylene, methanol or n- butanol. Thus for example, one may use a reaction pressure of from about 0.1 to about 1.0 atmospheres.
• the prehydrolyzed intermediate is condensed with the MX n reactant.
• the mole ratio of MX n to intermediate is from about 0.25 to 1 to about 4 to 1. This step can involve a partial hydrolysis of the MX n reactant prior to its condensation; however, it is to be understood that the condensation can at least to some extent occur via an alcohol producing condensation or similar reaction such as illustrated using a silicon tetraalkoxide by the equation:
• the water necessary for the composite forming step can come from three sources: (1) water present in the acid/water mixture at the end of the prehydrolysis step, (2) water that evolves from the water producing condensation reaction, and (3) water added at the beginning or during the composite forming step. It is often favorable to limit the amount of water present when the MX n reactant or reactants are added. It may be convenient to conduct the composite forming step in the presence of the acid/water mixture which remains after the prehydrolysis step and which contains the prehydrolyzed intermediate. The MX n compound can be added all at once or in increments.
• the composite forming reaction is generally conducted at a temperature in the range of from about -35°C to about 130°C and preferably is conducted at a temperature of from about -10°C to about 75°C. Reaction at room temperature or thereabouts is highly preferred in many instances.
• the time employed for the composite forming step is not a truly independent variable, but is dependent at least in part on the inherent reactivity of the reacting materials, the quantity employed, the catalyst used, and the reaction temperature (s) selected. Generally speaking, this time is from 30 minutes to 250 hours.
• the reaction pressure can be selected from those pressures discussed above when the prehydrolysis step was described.
• the TPSi(OR)3 composites of the invention have M-OH groups contributed by both the MX n reactant and the endcapped polymer. A surprisingly large percentage of these M-OH groups, also referred to herein as "reactive sites", can be reacted to provide additional M-OM bridges. This reaction is utilized in the method of the invention for the preparation of reacted composite to produce one of the embodiments of the reacted composites of the invention.
• Alternative embodiments of the reacted composites of the invention can be produced from organic-inorganic composites disclosed in U.S. Patent No. 5,096,942. Disclosed therein are organic-inorganic composites prepared by the reaction of endcapped polymers having the general structure TPESi(OR)3 and MX n reactants, in which T and P and other designations are the same as elsewhere herein. Other alternative embodiments of the reacted composites of the invention can be prepared from the star polymers disclosed in U.S. patent application No. 555,505. In the method of the invention for preparing reacted composites, TP-organo-silane, such as a TPSi (OR) 3 composite or star polymer, is reacted with a
• secondary condensation reactant that is, a small molecule or linear polymer bearing a group which is capable of reacting with the H- of a silanol or other metal hydroxy and forming an M-O-M bridge.
• exemplary silanol group reactions are tabulated in Her, Ralph K. , “The Chemistry of Silica”, John Wiley & Sons, New York, 1979.
• Suitable secondary condensation reactants are chlorosilanes, carboxylic acids, alkoxysilanes, and alcohols.
• useful secondary hydrolysis-condensation reactants are: trimethylchlorosilane, methacryloxypropyldimethyl- chlorosilane, n-decyldimethyl-chlorosilane, 3- cyanopropyldimethylchlorosilane, 2- (4- chlorosulfonylphenyl) ethyldimethylchlorosilane, 3- chloropropyldimethylchlorosiloane, n-butyldimethyl- chorosilane, 1, 6-bis (chlorodimethylsilyl)hexane, and 3- aminopropyldiisopylethoxysilane.
• Useful linear polymers include the above-disclosed endcapped polymers having the general structure TPSi (OR) 3 and endcapped polymers disclosed in U.S. Patent No. 4,933,391. Other suitable linear polymers are disclosed in the other references listed above for endcapped polymers. Because of this capacity to incorporate a variety of moieties, the reacted composites of the invention can have a wide variety of uses. For example, the reactive sites can carry and, in effect, disperse in a film or the like specific groups which provide a desired function, such as dye moieties for photography. Reaction of the organic-inorganic composite or star polymer and the secondary condensation reactant is performed in solution or as a melt without solvent or with a non-solvent. If solvent is used, selection of that solvent is not critical.
• Suitable solvents include cyclohexane, toluene, chloroform, and other similar materials.
• a convenient solution concentration is 15-20 percent solids.
• the reaction temperature is not critical, however, a temperature of 25°C or higher is desirable to increase the rate and extent of reaction. Any reaction pressure can be employed, however, atmospheric pressure is convenient.
• the secondary condensation reactant can be added in an amount in stoichiometric excess of the number of reactive sites or a less amount may be used if incomplete reaction is desired.
• a convenient amount of secondary condensation reactant for high levels of conversion is a tenfold excess of reactant to residual reactive silanols.
• the reaction can be allowed to proceed until the level of conversion has reached a constant value by 2 9si NMR analysis. Convenient times are generally 0.2 to 48 hours.
• the reacted composite produced can be isolated from solution by solvent evaporation or precipitation into nonsolvent.
• the latter procedure provides the added benefit of removing any unreacted silane.
• Reacted composites can be differentiated from their precursors on the basis of the presence of secondary subunits and also on the basis of relative percentages of metal atoms bearing different numbers of -OM groups, that is metal atoms bonded by 1, 2, 3, or more oxygen bridges to other metal atoms.
• the following nomenclature is used herein to designate those metal atoms.
• a ⁇ l silicon is bonded to one other metal atom through an oxygen bridge.
• Each silicon in the moiety Si-O-Si is a T**- silicon.
• Q3 and the like refer to metal atoms of the inorganic core, contributed by the MXn reactant, bearing the superscripted number of oxygen-metal bridges.
• Star polymers and reacted composites of star polymers lack Q3 and Q 4 metal atoms.
• T and "Q" metal atoms are described as percentages of total metal atoms. Percent condensation is equal to the number of condensed metal atoms, that is, "T" and "Q” metal atoms, divided by the total number of metal atoms, both condensed and uncondensed.
• the percentage of T 2 metal atoms decreased and the percentage of ⁇ metal atoms increased in comparison to star polymer precursors.
• the percentages of both and Q metal atoms decreased and the percentages of 3 and Q 4 metal atoms increased.
• the conversion of star polymer or organic-inorganic composite to reacted composite resulted in an increase in the condensation of metal atoms of about 50 to about 90 percent. This extent of incorporation of additional moieties into the star polymers and organic-inorganic composites was surprising. This is particularly true in view of the anomalous behavior of ⁇ l metal atoms.
• Example 1 a star polymer was 66 percent condensed and the reacted composite was 74 percent condensed. The star polymer was 16 percent ⁇ l. In the reacted composite no ⁇ l metal atoms were observed. In Example 4, a TPSi(OR) 3 composite showed 8 percent ⁇ l groups. The reacted composite showed 7 percent ⁇ l groups. This difference in the reactions of ⁇ l metal atoms in the methods of the invention for preparing reacted composites is very surprising and cannot be fully explained, other than noting that sterically hindered sites are evidenced by limited cluster growth and thus the Examples evidence unexpected differences m the accessibility of reactive sites .
• the reactor was a 250 mL, 1 neck, round-bottom flask equipped with a magnetic stirrer and a rubber septum. The septum was secured in place with copper wire in order that a positive pressure of ultra pure nitrogen could be maintained.
• the reactor was assembled while hot, and subsequently flamed under a nitrogen purge. After the flask had cooled, the polymerization solvent (tetrahydrofuran) was added to the reactor via a double-ended needle (cannula) . The reactor was submerged into a -78°C bath and allowed to reach thermal equilibrium. Purified styrene monomer was charged into the reactor with a syringe.
• the calculated amount of initiator was quickly syringed into the reactor and immediately one could see the formation of the orange polystyrl lithium anion.
• the polymerization was allowed to proceed for 20 minutes to ensure complete conversion.
• the endcapping reagent (50% molar excess compared to lithium) was added quickly via a syringe.
• the complete disappearance of the orange color was indicative of complete deactivation of the polymeric carbanion.
• the polymers (molecular weights greater than 3000 g/mole) were precipitated in HPLC grade methanol which contained ⁇ 0.05% water (determined by titration) .
• the precipitation and vacuum filtration were conducted under a nitrogen blanket to minimize hydrolysis of the trialkoxysilyl end-groups. Residual solvent was removed in vacuo at 80°C for 12 to 18 hours.
• C4H9-polystyrene-CH2-para-phenyl-Si(OCH3)3 endcapped polymer was dissolved in tetrahydrofuran to provide an approximately 15-18 percent (weight/weight) solution.
• a 4:1 molar ratio of water to silicon was added as a 0.15 N solution of HC1. The solvent was allowed to evaporate slowly at room temperature for 4 days. The reaction product was then heated at 120°C for 48 hours.
• TMOS tetramethoxysilane
• Star polymer was prepared as disclosed above using C-jHg-polystyrene-C ⁇ -para-phenyl-Si (OCH3)3 end ⁇ capped polymer having a molecular weight of 2,900 determined by Size Exclusion Chromatography (SEC) in tetrahydrofuran at 30°C using a viscometry detector and universal calibration with polystyrene standards. 29si Nuclear magnetic resonance characterization was per ⁇ formed using a Bruker AM-500 spectrometer at 99.32 MHz. All samples were referenced to tetramethylsilane (TMS) .
• SEC Size Exclusion Chromatography
• Chromium acetylacetonate [Cr(acac)3] was added at approximately 0.015 M to reduce the longitudinal relax ⁇ ation time for the 29si NMR spectra.
• the spectra were obtained using inverse-gated decoupling (decoupler on during acquisition and off during relaxation delay) to suppress any negative nuclear Overhauser effect.
• the relaxation agent and decoupling sequence facilitated quantitative measurements.
• the 29si NMR indicated that silicon atoms were condensed 66% percent to Si-O-Si and that the distribution was 16% T 1 , 70% T 2 , and 14% T 3 .
• the star polymer was readily dissolved in tetrahydrofuran at 25°C to provide a 15-20 percent
• the star polymer was prepared as described in
• Example 1 The star polymer was then dissolved in tetrahydrofuran at 25°C to provide a 15-20 percent (weight/volume) solution. Endcapped polymer trimethoxy(silylphenylmethyl) terminated polystyrene, which has the general formula T-P-E-Si (OCH3) 3, and having the molecular weight of 10,100 was added to the star polymer solution. The reaction mixture was maintained at 25°C for 24 hours. The reacted composite produced was isolated by drying and precipitation. Molecular weight analysis of the reacted composite produced was conducted as described in Example 1 and indicated an increase in molecular weight equivalent to the addition of 2.4 endcapped polymer moieties to each star polymer macromolecule. EXAMPLE 3
• Example 2 The procedures of Example 2 were followed with the following exceptions.
• the endcapped polymer used was the same as in Example 2 except the molecular weight was 45,800.
• the reaction mixture was allowed to react for 24 hours.
• Molecular weight analysis of the reacted composite produced was conducted as described in Example 1 and indicated an increase in molecular weight equivalent to the addition of 1.1 endcapped polymer moieties to each star polymer macromolecule.
• the TPSi (OR) 3 composite was prepared as follows. Approximately 1.0 grams of C4H9 ⁇ polystyrene- benzyl-Si (OCH2CH3) 3 endcapped polymer was dissolved in tetrahydrofuran (approximately 0.075 M) . The endcapped polymer was then prehydrolyzed. For the prehydrolysis, a 1.0 M HC1 solution was added to the tetrahydrofuran solution of the polymer in an amount such that the water: silicon ratio was 4:1. The resultant mixture was maintained at 30°C for 22.0 hours at atmospheric pressure, at which time an additional 16 equivalents of 1 M HC1 was added.
• the TPSi (OR) 3 composite was analyzed as follows: 29si Nuclear magnetic resonance characterization was performed as in Example 1 and indicated that silicon atoms were condensed as follows: T 63% and Q 85%. The distribution was 13% T 1 , 31% T 2 , 7% T 3 , 30% Q 3 and 19% Q 4 .
• the organic-inorganic composite was readily dissolved in tetrahydrofuran at 25°C. Trimethylchorosilane was added in a ten-fold excess and the reaction mixture was reacted for about 5 hours at 25°C. Analyses, conducted as described above, gave a final distribution of 10% ⁇ , 20% T 2 , 20% T 3 , 15% Q 3 and 35% Q 4 . The final values for condensation were T 73% and Q 93%.
• TPESi(OR)3 composite was prepared as described above, having a molecular weight of approximately 100,000 determined by the same procedures used in Example 1. 9si Nuclear magnetic resonance characterization was performed as in Example 1 and indicated that silicon atoms were condensed as follows: T 82% and Q 85%. The distribution was 15% T 2 , 12% T 3 , 5% Q 2 , 34% Q 3 and 34% Q 4 .
• the organic- inorganic composite was readily dissolved in tetrahydrofuran at 25°C. Trimethylchorosilane in ten ⁇ fold excess was added and the reaction mixture was reacted for 48 hours at 25°C.

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  • 1992-08-21 JP JP5504573A patent/JPH06501739A/ja active Pending
  • 1992-08-21 EP EP19920918687 patent/EP0554439A1/de not_active Withdrawn
  • 1992-08-21 WO PCT/US1992/007001 patent/WO1993004094A1/en not_active Application Discontinuation
  • 1992-08-21 CA CA 2093912 patent/CA2093912A1/en not_active Abandoned

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