The present invention is generally related to polymer nanoparticles. More particularly, the present invention provides polymer nanoparticles with a controlled architecture of nano-necklace, nano-cylinder, nano-ellipsoid, or nano-sphere, as examples. The present invention also provides a method of preparing the polymer nanoparticles and a rubber article including a formulation comprising the polymer nanoparticles.
Tires are often subjected to rough road conditions that produce repetitive, localized high-pressure pounding on the tire. These stresses can cause fatigue fracture and lead to crack formation and crack growth. This degradation of the tire has also been referred to as chipping or chunking of the tread surface or base material. In an attempt to prevent this degradation, it is known to add reinforcements such as carbon black, silicas, silica/silanes, or short fibers into the tire formulation. Silica has been found advantageous due to its ability to deflect and suppress cut prolongation, while silanes have been added to bind the silica to unsaturated elastomers. The fibers that have been added include nylon and aramid fibers.
It is also known that the addition of polyolefins to rubber compositions can provide beneficial properties. For example, low molecular weight high density polyethylene, and high molecular weight, low density polyethylene, are known to improve the tear strength of polybutadiene or natural rubber vulcanizates. In the tire art, it has also been found that polyethylene increases the green, tear strength of carcass compounds and permits easy extrusion in calendaring without scorch. Polypropylene likewise increases the green strength of butyl rubber. Polypropylene has also been effective in raising the static and dynamic modulus of rubber, as well as its tear strength. Over the past several years, polymer nano-particles have attracted increased attention not only in the technical fields such as catalysis, combinatorial chemistry, protein supports, magnets, and photonics, but also in the manufacture of rubbery products such as tires. For example, nano-particles can modify rubbers by uniformly dispersing throughout a host rubber composition as discrete particles. The physical properties of rubber such as moldability and tenacity can often be improved through such modifications. Moreover, some nano-particles such as polymer nano-strings may serve as a reinforcement material for rubber in order to overcome the above-mentioned drawbacks associated with polyolefin and silica reinforcement. For example, polymer nano-strings are capable of dispersing evenly throughout a rubber composition, while maintaining a degree of entanglement between the individual nano-strings, leading to improved reinforcement. However, indiscriminate addition of nano-particles to rubber may cause degradation of the matrix rubber material.
Advantageously, the present invention provides methods for preparation of polymer nanoparticles with well-controlled architectures such as nano-necklace, nano-cylinder, nano-ellipsoid, and nano-sphere. The polymer nanoparticles may be used as, for example, additives for rubber products.
One aspect of the present invention provides polymer nanoparticles with a controlled architecture selected from the group consisting of nano-necklace, nano-cylinder, nano-ellipsoid, and nano-sphere. The polymer nanoparticle comprises a core polymerized from multiple-vinyl-substituted aromatic hydrocarbons, a shell polymerized from alkyl-substituted styrene, and a polystyrene layer between the core and the shell.
Another aspect of the invention provides a method of preparing polymer nanoparticles with a controlled architecture selected from the group consisting of nano-necklace, nano-cylinder, nano-ellipsoid, and nano-sphere.
A further aspect of the invention provides a rubber article including a formulation comprising the polymer nanoparticles with a controlled architecture selected from the group consisting of nano-necklace, nano-cylinder, nano-ellipsoid, and nano-sphere.
The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the invention. In the drawings appended hereto:
It is to be understood herein, that if a “range” or “group” is mentioned with respect to a particular characteristic of the present invention, for example, molecular weight, ratio, percentage, chemical group, and temperature etc., it relates to and explicitly incorporates herein each and every specific member and combination of sub-ranges or sub-groups therein whatsoever. Thus, any specified range or group is to be understood as a shorthand way of referring to each and every member of a range or group individually as well as each and every possible sub-range or sub-group encompassed therein; and similarly with respect to any sub-ranges or sub-groups therein.
The present invention provides polymer nanoparticles with controlled architecture. The controlled architecture of the polymer nanoparticle may be nano-necklace, nano-cylinder, nano-ellipsoid, or nano-sphere. The nanoparticle comprises a core polymerized from multiple-vinyl-substituted aromatic hydrocarbons; a shell polymerized from alkyl-substituted styrene; and a polystyrene layer between the core and the shell.
The polymer nanoparticles with controlled architecture can be formed by dispersion polymerization, although emulsion polymerization may also be contemplated. In preferred exemplary embodiments, the method of the invention comprises a multi-stage anionic polymerization. Multi-stage anionic polymerizations have been conducted to prepare block-copolymers, for example in U.S. Pat. No. 4,386,125, which is incorporated herein by reference.
The polymer nanoparticles with controlled architecture are formed from diblock copolymer chains having a poly(alkyl-substituted styrene) block and a polystyrene block. Living polystyrene blocks may be crosslinked with a multiple-vinyl-substituted aromatic hydrocarbon to form the desired polymer nanoparticles with controlled architecture. The polymer nanoparticles preferably retain their discrete nature with little or no polymerization between each other. In preferred embodiments, the nanoparticles are substantially monodisperse and uniform in shape.
The liquid hydrocarbon medium can function as the dispersion solvent, and may be selected from any suitable aliphatic hydrocarbons, alicyclic hydrocarbons, or mixture thereof, with a proviso that it exists in liquid state during the nanoparticles' formation procedure. Exemplary aliphatic hydrocarbons include, but are not limited to, pentane, isopentane, 2,2 dimethyl-butane, hexane, heptane, octane, nonane, decane, and the like. Exemplary alicyclic hydrocarbons include, but are not limited to, cyclopentane, methyl cyclopentane, cyclohexane, methyl cyclopentane, cycloheptane, cyclooctane, cyclononane, cyclodecane, and the like. Generally, aromatic hydrocarbons and polar solvents are not preferred as the liquid medium. In exemplified embodiments, the liquid hydrocarbon medium comprises hexane.
The alkyl-substituted styrene monomer may have a structure represented by the formula as shown below:
in which m in an integer and 1≦m≦5, preferably m is 1 or 2; and R1 may be selected from saturated or unsaturated, substituted or unsubstituted, straight or branched, cyclic or acyclic C3-C8 alkyl groups. Typically, styrenes with polar groups such as chloride substituents are not used in anionic polymerization.
The alkyl-substituted styrene monomer(s) may be selected from one or more of the compounds as shown below:
The alkyl-substituted styrene monomer can comprise tert-butyl styrene (TbST) such as para-tert-butyl styrene as shown below:
Without being bound to any theory, it is believed that the alkyl group in the alkyl-substituted styrene monomer renders the poly(alkyl-substituted styrene) block more soluble or miscible in a selected liquid hydrocarbon medium than the polystyrene block, facilitating the subsequent micelle assembling and nanoparticle formation from the poly(alkyl-substituted styrene-co-styrene) diblock living polymers.
The polymerizing of alkyl-substituted styrene monomers into a poly(alkyl-substituted styrene) block is initiated via addition of anionic initiators that are known in the art. For example, the anionic initiator can be selected from any known organolithium compounds. Suitable organolithium compounds are represented by the formula as shown below:
R(Li)x
wherein R is a hydrocarbyl group having 1 to x valence(s). R generally contains 1 to 20, preferably 2-8, carbon atoms per R group, and x is an integer of 1-4. Typically, x is 1, and the R group includes aliphatic radicals and cycloaliphatic radicals, such as alkyl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl, alkenyl, as well as aryl and alkylaryl radicals.
Specific examples of R groups include, but are not limited to, alkyls such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-amyl, isoamyl, n-hexyl, n-octyl, n-decyl, and the like; cycloalkyls and alkylcycloalkyl such as cyclopentyl, cyclohexyl, 2,2,1-bicycloheptyl, methylcyclopentyl, dimethylcyclopentyl, ethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl, ethylcyclohexyl, isopropylcyclohexyl, 4-butylcyclohexyl, and the like; cycloalkylalkyls such as cyclopentyl-methyl, cyclohexyl-ethyl, cyclopentyl-ethyl, methyl-cyclopentylethyl, 4-cyclohexylbutyl, and the like; alkenyls such as vinyl, propenyl, and the like; arylalkyls such as 4-phenylbutyl; aryls and alkylaryls such as phenyl, naphthyl, 4-butylphenyl, p-tolyl, and the like.
Other lithium initiators include, but are not limited to, 1,4-dilithiobutane, 1,5-dilithiopetane, 1,10-dilithiodecane, 1,20-dilithioeicosane, 1,4-dilithiobenzene, 1,4-dilithionaphthalene, 1,10-dilithioanthracene, 1,2-dilithio-1,2-diphenylethane, 1,3,5-trilithiopentane, 1,5,15-trilithioeicosane, 1,3,5-trilithiocyclohexane, 1,3,5,8-tetralithiodecane, 1,5,10,20-tetralithioeicosane, 1,2,4,6-tetralithiocyclohexane, 4,4′-dilithiobiphenyl, and the like. Preferred lithium initiators include n-butyllithium, sec-butyllithium, tert-butyllithium, 1,4-dilithiobutane, and mixtures thereof.
Other lithium initiators which can be employed are lithium dialkyl amines, lithium dialkyl phosphines, lithium alkyl aryl phosphines and lithium diaryl phosphines. Functionalized lithium initiators are also contemplated as useful in the present invention. Preferred functional groups include amines, formyl, carboxylic acids, alcohol, tin, silicon, silyl ether and mixtures thereof.
In selected embodiments, n-butyllithium, sec-butyllithium, tert-butyllithium, or mixture thereof are used to initiate the polymerization of alkyl-substituted styrene monomers into a poly(alkyl-substituted styrene) block.
The polymerizing of alkyl-substituted styrene monomers into a poly(alkyl-substituted styrene) block may last until the reaction is completed and a predetermined degree of polymerization DP1 is obtained. The polymerization reaction of this step may last typically from about 0.5 hours to about 24 hours, preferably from about 0.5 hours to about 10 hours, more preferably from about 0.5 hours to about 4 hours.
The anionic polymerization of the invention may be conducted in the presence of a modifier, so as to, for example, increase the reaction rate and equalize the reactivity ratio of monomers. The modifiers used in the present invention may be linear oxolanyl oligomers represented by the structural formula (IV) and cyclic oligomers represented by the structural formula (V), as shown below:
wherein R14 and R15 are independently hydrogen or a C1-C8 alkyl group; R16, R17, R18, and R19 are independently hydrogen or a C1-C6 alkyl group; y is an integer of 1 to 5 inclusive, and z is an integer of 3 to 5 inclusive.
Specific examples of modifiers include, but are not limited to, oligomeric oxolanyl propanes (OOPs); 2,2-bis-(4-methyl dioxane); bis(2-oxolanyl) methane; 1,1-bis(2-oxolanyl) ethane; bistetrahydrofuryl propane; 2,2-bis(2-oxolanyl) propane; 2,2-bis(5-methyl-2-oxolanyl) propane; 2,2-bis-(3,4,5-trimethyl-2-oxolanyl) propane; 2,5-bis(2-oxolanyl-2-propyl) oxolane; octamethylperhydrocyclotetrafurfurylene (cyclic tetramer); 2,2-bis(2-oxolanyl) butane; and the like. A mixture of two or more 1,2-microstructure controlling agents also can be used. The preferred modifiers for use in the present invention are oligomeric oxolanyl propanes (OOPs).
Other suitable modifiers are hexamethylphosphoric acid triamide, N,N,N′,N′-tetramethylethylene diamine, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, tetrahydrofuran, 1,4-diazabicyclo[2.2.2] octane, diethyl ether, triethylamine, tri-n-butylamine, tri-n-butylphosphine, p-dioxane, 1,2-dimethoxy ethane, dimethyl ether, methyl ethyl ether, ethyl propyl ether, di-n-propyl ether, di-n-octyl ether, anisole, dibenzyl ether, diphepyl ether, dimethylethylamine, bis-oxalanyl propane, tri-n-propyl amine, trimethyl amine, triethyl amine, N,N-dimethyl aniline, N-ethylpiperidine, N-methyl-N-ethyl aniline, N-methylmorpholine, and tetramethylenediamine etc. A mixture of one or more modifiers also can be used.
The poly(alkyl-substituted styrene) block is polymerized first, followed by polystyrene block, positioning the living end of the diblock polymer on polystyrene block to facilitate later crosslinking.
In copolymerizing styrene monomers with the poly(alkyl-substituted styrene) block to produce a polystyrene block with a predetermined degree of polymerization DP2 to obtain a diblock copolymer, i.e. poly(alkyl-substituted styrene-co-styrene), the polymerization time for this step may last typically from about 0.5 hours to about 24 hours, preferably from about 0.5 hours to about 10 hours, more preferably from about 0.5 hours to about 4 hours.
A micelle-like structure may be formed by aggregating the poly(alkyl-substituted styrene-co-styrene)s. The polystyrene blocks are typically directed toward the center of the micelle and the poly(alkyl-substituted styrene) blocks are typically extended away from the center.
A multiple-vinyl-substituted aromatic hydrocarbon may then be copolymerized with the polystyrene block of the diblock copolymers in the micelle-like structures to crosslink the diblock copolymers and to form polymer nanoparticles with controlled architecture. Preferably, the multiple-vinyl-substituted aromatic hydrocarbon has a higher affinity with the polystyrene block than with the poly(alkyl-substituted styrene) blocks. As such, the multiple-vinyl-substituted aromatic hydrocarbon is able to migrate to the center of the micelles, and crosslink the center core of the micelle to form the polymer nanoparticles with controlled architecture. Consequently, the polymer nanoparticles with controlled architecture are formed from the micelles with a core made from multiple-vinyl-substituted aromatic hydrocarbons, a shell made from alkyl-substituted styrene, and a polystyrene layer between the core and the shell.
The multiple-vinyl-substituted aromatic hydrocarbon has a formula as shown below:
in which p is an integer and 2≦p≦6, preferably, p is 2 or 3, more preferably p is 2, i.e. di-vinyl-benzene (DVB).
In certain embodiments, the di-vinyl-benzene may be selected from any one of the following isomers or any combination thereof:
In copolymerizing a multiple-vinyl-substituted aromatic hydrocarbon with the polystyrene block of the diblock copolymers in the micelles to crosslink the diblock copolymers and to form polymer nanoparticles with controlled architecture, the copolymerization time for this step may last typically from about 0.5 hours to about 24 hours, preferably from about 0.5 hours to about 10 hours, more preferably from about 0.5 hours to about 4 hours.
The polymer nano-particles of the invention are similar to star polymers. A star polymer is a polymer comprised of star macromolecules. A star macromolecule is a macromolecule containing a single branch point from which linear chains (arms) emanate.
The polymerization reactions used to prepare the polymer nanoparticles with controlled architecture may be terminated with a terminating agent. Suitable terminating agents include, but are not limited to, alcohols such as methanol, ethanol, propanol, and isopropanol; amines, MeSiCl3, Me2SiCl2, Me3SiCl, SnCl4, MeSnCl3, Me2SnCl2, Me3SnCl, and etc. In exemplified embodiments, the polymerization reaction mixture was cooled down and dropped in an isopropanol/acetone solution optionally containing an antioxidant such as butylated hydroxytoluene (BHT). The isopropanol/acetone solution may be prepared by mixing 1 part by volume of isopropanol and 4 parts by volume of acetone.
In the following four sections, specific conditions for the preparation of nanoparticles with controlled architecture of nano-necklace, nano-cylinder, nano-ellipsoids or nano-spheres will be described in details.
(I) Nano-Necklaces
In some exemplary embodiments, the controlled architecture of the polymer nanoparticle is in the shape of nano-necklace. The mean diameter of the necklace may be broadly within the range of from about 5 nm to about 100 nm, preferably within the range of from about 5 nm to about 60 nm, more preferably within the range of from about 10 nm to about 40 nm, and most preferably within the range of from about 30 nm to about 40 nm. The length of the necklace may be broadly within the range of from about 0.1 μm to about 1,000 μm, preferably within the range of from about 0.1 μm to about 100 μm, more preferably within the range of from about 0.1 μm to about 10 μm, and most preferably within the range of from about 0.1 μm to about 5 μm.
In preparing the nano-necklaces, the predetermined degree of polymerization DP1 of the poly(alkyl-substituted styrene) block may be broadly within the range of from about 20 to about 1,000, preferably within the range of from about 50 to about 300, more preferably within the range of from about 70 to about 100, and most preferably within the range of from about 70 to about 90. Alternatively, the number average molecular weight (Mn1) of the poly(alkyl-substituted styrene) block may be controlled within the range of from about 3,000 to about 150,000, more preferably within the range of from about 8,000 to about 50,000, and most preferably within the range of from about 10,000 to about 15,000.
In preparing the nano-necklaces, the predetermined degree of polymerization DP2 of the polystyrene block may be broadly within the range of from about 20 to about 1,500, preferably within the range of from about 40 to about 1,000, more preferably within the range of from about 100 to about 1,000, and most preferably within the range of from about 200 to about 500. Alternatively, the number average molecular weight (Mn2) of the polystyrene block may be controlled within the range of from about 2,000 to about 150,000, more preferably within the range of from about 4,000 to about 100,000, and most preferably within the range of from about 20,000 to about 50,000.
When copolymerizing multiple-vinyl-substituted aromatic hydrocarbons with the polystyrene blocks of the poly(alkyl-substituted styrene-co-styrene) to crosslink the diblock copolymers and to form the nano-necklaces, the weight concentration of the poly(alkyl-substituted styrene-co-styrene) in the liquid hydrocarbon medium may be broadly within the range of from about 30% to about 90%, preferably within the range of from about 30% to about 80%, more preferably within the range of from about 30% to about 70%, and most preferably within the range of from about 30% to about 60%. The weight concentration of the multiple-vinyl-substituted aromatic hydrocarbon such as DVB in the liquid hydrocarbon medium may be broadly within the range of from about 1% to about 10%, preferably within the range of from about 1% to about 8%, more preferably within the range of from about 2% to about 6%, and most preferably within the range of from about 3% to about 6%.
In a variety of exemplary embodiments, the process of preparing the polymer nanoparticles with controlled architecture of nano-necklace may be conducted at a temperature of from about 50° F. to about 400° F., preferably form about 50° F. to about 300° F., and more preferably form about 70° F. to about 150° F.
(II) Nano-Cylinders
In some exemplary embodiments, the controlled architecture of the polymer nanoparticle is in the shape of nano-cylinders. The mean diameter of the cylinders may be broadly within the range of from about 5 nm to about 100 nm, preferably within the range of from about 5 nm to about 60 nm, more preferably within the range of from about 10 nm to about 50 nm, and most preferably within the range of from about 35 nm to about 45 nm. The length of the cylinder may be broadly within the range of from about 200 nm to about 5 μm, preferably within the range of from about 200 nm to about 1 μm, more preferably within the range of from about 200 nm to about 0.5 μm, and most preferably within the range of from about 200 nm to about 0.25 μm. The average length of the cylinder may also be from about 0.15 μm to about 0.25 μm.
In preparing the nano-cylinders, the predetermined degree of polymerization DP1 of the poly(alkyl-substituted styrene) block may be broadly within the range of from about 20 to about 1,000, preferably within the range of from about 50 to about 300, more preferably within the range of from about 70 to about 100, and most preferably within the range of from about 70 to about 90. Alternatively, the number average molecular weight (Mn1) of the poly(alkyl-substituted styrene) block may be controlled within the range of from about 3,000 to about 150,000, more preferably within the range of from about 8,000 to about 50,000, and most preferably within the range of from about 10,000 to about 15,000.
In preparing the nano-cylinders, the predetermined degree of polymerization DP2 of the polystyrene block may be broadly within the range of from about 20 to about 1,500, preferably within the range of from about 40 to about 1,000, more preferably within the range of from about 100 to about 1,000, and most preferably within the range of from about 200 to about 500. Alternatively, the number average molecular weight (Mn2) of the polystyrene block may be controlled within the range of from about 2,000 to about 150,000, more preferably within the range of from about 4,000 to about 100,000, and most preferably within the range of from about 20,000 to about 50,000.
When copolymerizing multiple-vinyl-substituted aromatic hydrocarbons with the polystyrene blocks of the poly(alkyl-substituted styrene-co-styrene) to crosslink the diblock copolymers and to form the nano-cylinders, the w eight concentration of the living poly(alkyl-substituted styrene-co-styrene) in the liquid hydrocarbon medium may be broadly within the range of from about 25% to about 30%. The weight concentration of the multiple-vinyl-substituted aromatic hydrocarbon such as DVB in the liquid hydrocarbon medium may be broadly Within the range of from about 1% to about 10%, preferably within the range of from about 1% to about 5%, more preferably within the range of from about 1% to about 4%, and most preferably within the range of from about 1% to about 3%.
In a variety of exemplary embodiments, the process of preparing the polymer nanoparticles with controlled architecture of a nano-cylinder may be conducted at a temperature of from about 50° F. to about 400° F., preferably form about 50° F. to about 300° F., and more preferably form about 70° F. to about 150° F.
(III) Nano-Spheres
In some exemplary embodiments, the controlled architecture of the polymer nanoparticle is in the shape of nano-spheres. The mean diameter of the spheres may be broadly within the range of from about 5 nm to about 200 nm, preferably within the range of from about 5 nm to about 100 nm, more preferably within the range of from about 5 nm to about 40 nm, and most preferably within the range of from about 25 nm to about 35 nm.
In preparing the nano-spheres, the predetermined degree of polymerization DP1 of the poly(alkyl-substituted styrene) block may be broadly within the range of from about 20 to about 2,000, preferably within the range of from about 50 to about 300, more preferably within the range of from about 50 to about 100, and most preferably within the range of from about 70 to about 90. Alternatively, the number average molecular weight (Mn1) of the poly(alkyl-substituted styrene) block may be controlled within the range of from about 3,000 to about 300,000, more preferably within the range of from about 8,000 to about 50,000, and most preferably within the range of from about 10,000 to about 15,000.
In preparing the nano-spheres, the predetermined degree of polymerization DP2 of the polystyrene block may be broadly within the range of from about 20 to about 3,000, preferably within the range of from about 40 to about 1,000, more preferably within the range of from about 100 to about 1,000, and most preferably within the range of from about 150 to about 500. Alternatively, the number average molecular weight (Mn2) of the polystyrene block may be controlled within the range of from about 2,000 to about 300,000, more preferably within the range of from about 4,000 to about 100,000, and most preferably within the range of from about 15,000 to about 50,000.
When copolymerizing multiple-vinyl-substituted aromatic hydrocarbons with the polystyrene blocks of the poly(alkyl-substituted styrene-co-styrene) to crosslink the diblock copolymers and to form the nano-spheres, the weight concentration of the poly(alkyl-substituted styrene-co-styrene) in the liquid hydrocarbon medium (M1) may be broadly within the range of from about 1% to about 25%, preferably within the range of from about 5% to about 25%, more preferably within the range of from about 6% to about 25%, and most preferably within the range of from about 10% to about 25%. The weight concentration of the multiple-vinyl-substituted aromatic hydrocarbon such as DVB in the liquid hydrocarbon medium (M2) may be broadly within the range of from about 1% to about 10%, preferably within the range of from about 1% to about 5%, more preferably within the range of from about 1% to about 4%, and most preferably within the range of from about 1% to about 3%.
In a variety of exemplary embodiments, the process of preparing the polymer nanoparticles with controlled architecture of nano-sphere may be conducted at a temperature of from about 50° F. to about 400° F., preferably form about 50° F. to about 300° F., and more preferably form about 70° F. to about 159° F.
(IV) Nano-Ellipsoid
In some exemplary embodiments, the controlled architecture of the polymer nanoparticle is in the shape of nano-ellipsoids. The average length of the major axis of the ellipsoids may be broadly within the range of from about 5 nm to about 200 nm, preferably within the range of from about 10 nm to about 100 nm, more preferably within the range of from about 10 nm to about 80 nm, and most preferably within the range of from about 10 nm to about 60 nm. The average length of the minor axis of the ellipsoids may be broadly within the range of from about 10 nm to about 100 nm, preferably within the range of from about 10 nm to about 80 nm, more preferably within the range of from about 10 nm to about 70 nm, and most preferably within the range of from about 20 nm to about 60 nm.
In preparing the nano-ellipsoids, the predetermined degree of polymerization DP1 of the poly(alkyl-substituted styrene) block may be broadly within the range of from about 20 to about 2,000, preferably within the range of from about 50 to about 300, more preferably within the range of from about 50 to about 200, and most preferably within the range of from about 140 to about 190. Alternatively, the number average molecular weight (Mn1) of the poly(alkyl-substituted styrene) block may be controlled within the range of from about 3,000 to about 300,000, more preferably within the range of from about 8,000 to about 50,000, and most preferably within the range of from about 22,000 to about 30,000.
In preparing the nano-ellipsoids, the predetermined degree of polymerization DP2 of the polystyrene block may be broadly within the range of from about 20 to about 3,000, preferably within the range of from about 40 to about 1,000, more preferably within the range of from about 100 to about 1,000, and most preferably within the range of from about 200 to about 300. Alternatively, the number average molecular weight (Mn2) of the polystyrene block may be controlled within the range of from about 2,000 to about 300,000, more preferably within the range of from about 4,000 to about 100,000, and most preferably within the range of from about 20,000 to about 30,000.
When copolymerizing multiple-vinyl-substituted aromatic hydrocarbons with the polystyrene blocks of the poly(alkyl-substituted styrene-co-styrene) to crosslink the diblock copolymers and to form the nano-spheres, the weight concentration of the poly(alkyl-substituted styrene-co-styrene) in the liquid hydrocarbon medium may be broadly within the range of from about 10% to about 25%, preferably within the range of from about 15% to about 25%, more preferably within the range of from about 15% to about 20%, and most preferably within the range of from about 16% to about 18%. The weight concentration of the multiple-vinyl-substituted aromatic hydrocarbon such as DVB in the liquid hydrocarbon medium (M2) may be broadly within the range of from about 1% to about 10%, preferably within the range of from about 1% to about 5%, more preferably within the range of from about 1% to about 3%, and most preferably within the range of from about 1% to about 2%.
In a variety of exemplary embodiments, the process of preparing the polymer nanoparticles with controlled architecture of nano-ellipsoid may be conducted at a temperature of from about 50° F. to about 400° F., preferably form about 70° F. to about 300° F., and more preferably form about 70° F. to about 150° F.
The polymer nanoparticles with controlled architecture of the invention and the method thereof may be widely utilized in the technical fields of rubbers, plastics, tire manufacture, medicine, catalysis, combinatorial chemistry, protein supports, magnets, photonics, electronics, cosmetics, and all other applications envisioned by the skilled artisan. For example, they can be used as processing aids and reinforcing fillers. Monodisperse polymer particles having a particle size above 2 microns are used as a reference standard for the calibration of various instruments, in medical research and in medical diagnostic tests.
In a variety of exemplary embodiments, rubber articles such as tires may be manufactured from a formulation comprising the polymer nanoparticles as described supra. References for this purpose may be made to, for example, U.S. patent application 2004/0143064 A1.
The following examples are included to provide additional guidance to those skilled in the art in practicing the claimed invention. The examples provided are merely representative of the work that contributes to the teaching of the present application. Accordingly, these examples are not intended to limit the invention, as defined in the appended claims, in any manner.
A 2-gallon reactor equipped with external jacked heating and internal agitation was used for all the preparations. Styrene in hexane (32.8 weight percent styrene), hexane, butyllithium (1.68 M) and BHT were used as supplied in the reactor room. Technical grade divinylbenzene (80%, mixture of isomers, purchased from Aldrich, item 41,456-5) was stored on aluminum oxide beads and calcium hydride under nitrogen. t-Butylstyrene (95% purchased from Aldrich, item 15669-8) was also stored on aluminum oxide beads and calcium hydride under nitrogen.
The reactor was charged with 1 lbs. hexane and 0.45 lbs. t-butylstyrene (TbST). The jacket of the reactor was heated to 130° F. When the batch reached 130° F., 3.0 ml of 1.6 M oops/hexane solution and 10 ml of 1.68 M butyl lithium/hexane solution were added. The polymerization exothermed after 5 minutes of reaction. After 1.5 hours, 3.0 lb. styrene/Hexane blend (containing 32.8 wt % styrene) were added to the reactor that was still maintaining at 130° F. An exothermic peak was observed after 10 minutes. After 1.5 hours, a sample was taken for GPC analysis. Then, 100 ml of divinylbenzene was added to the reaction mixture. After another 1.5 hours of reaction, the reaction mixture was cooled down and dropped in an isopropanol/acetone solution (about 500 mL/2 L) containing BHT. The solid was then filtered through cheesecloth and dried in vacuum.
GPC analysis of the intermediate product, based on a polystyrene/THF standard, indicated that ST-TBST block copolymer had the mean molecular weight (Mn) of 36600 with MW/Mn=1.07. The TEM analysis was taken on a hexane solution of the final product at 10−4 wt % concentration. A drop of the diluted solution was coated on a graphed copper micro-grid. After the solvent was vaporized, the grid was stained with RuO4 and was then examined by TEM. The results showed that the product synthesized contains nano-sized necklaces (see
The reactor was charged with 2 lbs. hexane and 0.45 lbs. t-butylstyrene (TbST). The jacket of the reactor was heated to 130° F. When the batch reached 130° F., 3.0 ml of 1.6 M oops/hexane solution and 10 ml of 1.68 M butyl lithium/hexane solution were added. The polymerization showed an exothermic peak after 5 minutes of reaction. After 1.5 hours, 3.0 lb. styrene/Hexane blend (containing 32.8 wt % styrene) were added to the reactor that was still maintaining at 130° F. An exothermic peak was observed after 10 minutes. After 1.5 hours, a sample was taken for GPC analysis. Then, 60 ml of divinylbenzene was added to the reaction mixture. After another 1.5 hours of reaction, the reaction mixture was cooled down and dropped in an isopropanol/acetone solution (about 500 mL/2 L) containing BHT. The solid was then filtered through cheesecloth and dried in vacuum.
GPC analysis of the intermediate product, based on a polystyrene/THF standard, indicated that the ST-TBST block copolymer had a mean molecular weight (Mn) of 34620 with Mw/Mn=1.11. The TEM analysis was taken on a hexane solution of the final product at 10−4 wt % concentration. A drop of the diluted solution was then coated on a graphed copper micro-grid. After the solvent was vaporized, the grid was stained with RuO4 and was then examined by TEM. The results showed that the product synthesized contains nano-sized cylinders (see
The reactor was charged with 2 lbs. hexane and 0.45 lbs. t-butylstyrene (TbST). The jacket of the reactor was heated to 125° F. When the batch reached 130° F., 3.0 ml of 1.6 M oops/hexane solution and 7 ml of 1.68 M butyl lithium/hexane solution were added. The polymerization showed an exothermic peak after 5 minutes of reaction. After 1.5 hours, 1.5 lb. styrene/Hexane blend (containing 32.8 wt % styrene) were added to the reactor that was still maintained at 130° F. An exothermic peak was observed after 10 minutes. After 1.5 hours, a sample was taken for GPC analysis. Then, 50 ml of divinylbenzene was added to the reaction mixture. After another 1.5 hours of reaction, the reaction mixture was cooled down and dropped in an isopropanol/acetone solution (about 500 mL/2 L) containing BHT. The solid was then filtered through cheesecloth and dried in vacuum.
GPC analysis of the intermediate product, based on a polystyrene/THF standard, indicated that the ST-TBST block copolymer had a mean molecular weight (Mn) of 31270 with Mw/Mn=1.07. The TEM analysis was taken on a hexane solution of the final product at 10−4 wt % concentration. A drop of the diluted solution was then coated on a graphed copper micro-grid. After the solvent was vaporized, the screen was examined by TEM. The results showed that the product synthesized contains nano-sized spheres (see
The reactor was charged with 4 lbs. hexane and 0.43 lbs. t-butylstyrene (TbST). The jacket of the reactor was heated to 130° F. When the batch reached 130° F., 3.0 ml of 1.6 M oops/hexane solution and 6 ml of 1.68 M butyl lithium/hexane solution were added. The polymerization showed an exothermic peak after 5 minutes of reaction. After 1.5 hours, 1.49 lb. styrene/Hexane blend (containing 32.8 wt % styrene) were added to the reactor that was still maintaining at 130° F. An exothermic peak was observed after 10 minutes. After 1.5 hours, a sample was taken for GPC analysis. Then, 50 ml of divinylbenzene was added to the reaction mixture. After another 1.5 hours of reaction, the reaction mixture was cooled down and dropped in an isopropanol/acetone solution (about 500 mL/2 L) containing BHT. The solid was then filtered through cheesecloth and dried in vacuum.
The TEM analysis was taken on a hexane solution of the final product at 10−4 wt % concentration. A drop of the diluted solution was then coated on a graphed copper micro-grid. After the solvent was vaporized, the screen was examined by TEM. The results showed that the product synthesized contains nano-sized ellipsoids (see
While the invention has been illustrated and described in typical embodiments, it is not intended to be limited to the details shown, since various modifications and substitutions can be made without departing in any way from the spirit of the present invention. As such, further modifications and equivalents of the invention herein disclosed may occur to persons skilled in the art using no more than routine experimentation, and all such modifications and equivalents are believed to be within the spirit and scope of the invention as defined by the following claims.
Number | Name | Date | Kind |
---|---|---|---|
2531396 | Carter et al. | Nov 1950 | A |
3598884 | Wei | Aug 1971 | A |
3793402 | Owens | Feb 1974 | A |
3840620 | Gallagher | Oct 1974 | A |
3972963 | Schwab et al. | Aug 1976 | A |
4233409 | Bulkley | Nov 1980 | A |
4247434 | Vanderhoff et al. | Jan 1981 | A |
4326008 | Rembaum | Apr 1982 | A |
4386125 | Shiraki et al. | May 1983 | A |
4463129 | Shinada et al. | Jul 1984 | A |
4543403 | Isayama et al. | Sep 1985 | A |
4598105 | Weber et al. | Jul 1986 | A |
4602052 | Weber et al. | Jul 1986 | A |
4659790 | Shimozato et al. | Apr 1987 | A |
4717655 | Fluwyler | Jan 1988 | A |
4725522 | Breton et al. | Feb 1988 | A |
4764572 | Bean, Jr. | Aug 1988 | A |
4773521 | Chen | Sep 1988 | A |
4774189 | Schwartz | Sep 1988 | A |
4788254 | Kawakubo et al. | Nov 1988 | A |
4829130 | Licchelli et al. | May 1989 | A |
4829135 | Gunesin et al. | May 1989 | A |
4837274 | Kawakubo et al. | Jun 1989 | A |
4837401 | Hirose et al. | Jun 1989 | A |
4861131 | Bois et al. | Aug 1989 | A |
4870144 | Noda et al. | Sep 1989 | A |
4871814 | Gunesin et al. | Oct 1989 | A |
4904730 | Moore et al. | Feb 1990 | A |
4904732 | Iwahara et al. | Feb 1990 | A |
4906695 | Blizzard et al. | Mar 1990 | A |
4920160 | Chip et al. | Apr 1990 | A |
4942209 | Gunesin | Jul 1990 | A |
5036138 | Stamhuis et al. | Jul 1991 | A |
5066729 | Srayer, Jr. et al. | Nov 1991 | A |
5073498 | Schwartz et al. | Dec 1991 | A |
5075377 | Kawakubo et al. | Dec 1991 | A |
5120379 | Noda et al. | Jun 1992 | A |
5130377 | Trepka et al. | Jul 1992 | A |
5169914 | Kaszas et al. | Dec 1992 | A |
5194300 | Cheung | Mar 1993 | A |
5219945 | Dicker et al. | Jun 1993 | A |
5227419 | Moczygemba et al. | Jul 1993 | A |
5237015 | Urban | Aug 1993 | A |
5241008 | Hall | Aug 1993 | A |
5247021 | Fujisawa et al. | Sep 1993 | A |
5256736 | Trepka et al. | Oct 1993 | A |
5262502 | Fujisawa et al. | Nov 1993 | A |
5290873 | Noda et al. | Mar 1994 | A |
5290875 | Moczygemba et al. | Mar 1994 | A |
5290878 | Yamamoto et al. | Mar 1994 | A |
5329005 | Lawson et al. | Jul 1994 | A |
5331035 | Hall | Jul 1994 | A |
5336712 | Austgen, Jr. et al. | Aug 1994 | A |
5362794 | Inui et al. | Nov 1994 | A |
5395891 | Obrecht et al. | Mar 1995 | A |
5395902 | Hall | Mar 1995 | A |
5399628 | Moczygemba et al. | Mar 1995 | A |
5399629 | Coolbaugh et al. | Mar 1995 | A |
5405903 | Van Westrenen et al. | Apr 1995 | A |
5421866 | Stark-Kasley et al. | Jun 1995 | A |
5436298 | Moczygemba et al. | Jul 1995 | A |
5438103 | DePorter et al. | Aug 1995 | A |
5447990 | Noda et al. | Sep 1995 | A |
5462994 | Lo et al. | Oct 1995 | A |
5514734 | Maxfield et al. | May 1996 | A |
5514753 | Ozawa et al. | May 1996 | A |
5521309 | Antkowiak et al. | May 1996 | A |
5525639 | Keneko et al. | Jun 1996 | A |
5527870 | Maeda et al. | Jun 1996 | A |
5530052 | Takekoshi et al. | Jun 1996 | A |
5580925 | Iwahara et al. | Dec 1996 | A |
5587423 | Brandstetter et al. | Dec 1996 | A |
5594072 | Handlin, Jr. et al. | Jan 1997 | A |
5614579 | Roggeman et al. | Mar 1997 | A |
5627252 | De La Croi Habimana | May 1997 | A |
5688856 | Austgen, Jr. et al. | Nov 1997 | A |
5707439 | Takekoshi et al. | Jan 1998 | A |
5728791 | Tamai et al. | Mar 1998 | A |
5733975 | Aoyama et al. | Mar 1998 | A |
5739267 | Fujisawa et al. | Apr 1998 | A |
5742118 | Endo et al. | Apr 1998 | A |
5763551 | Wunsch et al. | Jun 1998 | A |
5773521 | Hoxmeier et al. | Jun 1998 | A |
5777037 | Yamanaka et al. | Jul 1998 | A |
5811501 | Chiba et al. | Sep 1998 | A |
5834563 | Kimura et al. | Nov 1998 | A |
5847054 | McKee et al. | Dec 1998 | A |
5849847 | Quirk | Dec 1998 | A |
5855972 | Kaeding | Jan 1999 | A |
5883173 | Elspass et al. | Mar 1999 | A |
5891947 | Hall et al. | Apr 1999 | A |
5905116 | Wang et al. | May 1999 | A |
5910530 | Wang et al. | Jun 1999 | A |
5955537 | Steininger et al. | Sep 1999 | A |
5986010 | Clites et al. | Nov 1999 | A |
5994468 | Wang et al. | Nov 1999 | A |
6011116 | Aoyama et al. | Jan 2000 | A |
6020446 | Okamoto et al. | Feb 2000 | A |
6025416 | Proebster et al. | Feb 2000 | A |
6025445 | Chiba et al. | Feb 2000 | A |
6060549 | Li et al. | May 2000 | A |
6060559 | Feng et al. | May 2000 | A |
6087016 | Feeney et al. | Jul 2000 | A |
6087456 | Sakaguchi et al. | Jul 2000 | A |
6106953 | Zimmermann et al. | Aug 2000 | A |
6117932 | Hasegawa et al. | Sep 2000 | A |
6121379 | Yamanaka et al. | Sep 2000 | A |
6127488 | Obrecht et al. | Oct 2000 | A |
6147151 | Fukumoto et al. | Nov 2000 | A |
6180693 | Tang et al. | Jan 2001 | B1 |
6191217 | Wang et al. | Feb 2001 | B1 |
6197849 | Zilg et al. | Mar 2001 | B1 |
6204354 | Wang et al. | Mar 2001 | B1 |
6225394 | Lan et al. | May 2001 | B1 |
6252014 | Knauss | Jun 2001 | B1 |
6255372 | Lin et al. | Jul 2001 | B1 |
6268451 | Faust et al. | Jul 2001 | B1 |
6277304 | Wei et al. | Aug 2001 | B1 |
6348546 | Hiiro et al. | Feb 2002 | B2 |
6359075 | Wollum et al. | Mar 2002 | B1 |
6379791 | Cernohous et al. | Apr 2002 | B1 |
6383500 | Wooley et al. | May 2002 | B1 |
6395829 | Miyamoto et al. | May 2002 | B1 |
6420486 | DePorter et al. | Jul 2002 | B1 |
6437050 | Krom et al. | Aug 2002 | B1 |
6441090 | Demirors et al. | Aug 2002 | B1 |
6448353 | Nelson et al. | Sep 2002 | B1 |
6489378 | Sosa et al. | Dec 2002 | B1 |
6524595 | Perrier et al. | Feb 2003 | B1 |
6573313 | Li et al. | Jun 2003 | B2 |
6573330 | Fujikake et al. | Jun 2003 | B1 |
6598645 | Larson | Jul 2003 | B1 |
6649702 | Rapoport et al. | Nov 2003 | B1 |
6663960 | Murakami et al. | Dec 2003 | B1 |
6689469 | Wang et al. | Feb 2004 | B2 |
6693746 | Nakamura et al. | Feb 2004 | B1 |
6706813 | Chiba et al. | Mar 2004 | B2 |
6706823 | Wang et al. | Mar 2004 | B2 |
6727311 | Ajbani et al. | Apr 2004 | B2 |
6737486 | Wang | May 2004 | B2 |
6750297 | Yeu et al. | Jun 2004 | B2 |
6759464 | Ajbani et al. | Jul 2004 | B2 |
6774185 | Lin et al. | Aug 2004 | B2 |
6777500 | Lean et al. | Aug 2004 | B2 |
6780937 | Castner | Aug 2004 | B2 |
6835781 | Kondou et al. | Dec 2004 | B2 |
6858665 | Larson | Feb 2005 | B2 |
6861462 | Parker et al. | Mar 2005 | B2 |
6872785 | Wang et al. | Mar 2005 | B2 |
6875818 | Wang | Apr 2005 | B2 |
6908958 | Maruyama et al. | Jun 2005 | B2 |
6956084 | Wang et al. | Oct 2005 | B2 |
7056840 | Miller et al. | Jun 2006 | B2 |
7071246 | Xie et al. | Jul 2006 | B2 |
7112369 | Wang et al. | Sep 2006 | B2 |
7179864 | Wang | Feb 2007 | B2 |
7193004 | Weydert et al. | Mar 2007 | B2 |
7205370 | Wang et al. | Apr 2007 | B2 |
7217775 | Castner | May 2007 | B2 |
7238751 | Wang et al. | Jul 2007 | B2 |
7244783 | Lean et al. | Jul 2007 | B2 |
7291394 | Winkler et al. | Nov 2007 | B2 |
7347237 | Xie et al. | Mar 2008 | B2 |
7408005 | Zheng et al. | Aug 2008 | B2 |
20010053813 | Konno et al. | Dec 2001 | A1 |
20020007011 | Konno et al. | Jan 2002 | A1 |
20020045714 | Tomalia et al. | Apr 2002 | A1 |
20020095008 | Heinrich et al. | Jul 2002 | A1 |
20020144401 | Nogueroles Vines et al. | Oct 2002 | A1 |
20030004250 | Ajbani et al. | Jan 2003 | A1 |
20030032710 | Larson | Feb 2003 | A1 |
20030124353 | Wang et al. | Jul 2003 | A1 |
20030130401 | Lin et al. | Jul 2003 | A1 |
20030149185 | Wang et al. | Aug 2003 | A1 |
20030198810 | Wang et al. | Oct 2003 | A1 |
20030225190 | Borbely et al. | Dec 2003 | A1 |
20040033345 | Dubertret et al. | Feb 2004 | A1 |
20040059057 | Swisher et al. | Mar 2004 | A1 |
20040127603 | Lean et al. | Jul 2004 | A1 |
20040143064 | Wang | Jul 2004 | A1 |
20040198917 | Castner | Oct 2004 | A1 |
20050101743 | Stacy et al. | May 2005 | A1 |
20050182158 | Ziser et al. | Aug 2005 | A1 |
20050192408 | Lin et al. | Sep 2005 | A1 |
20050197462 | Wang et al. | Sep 2005 | A1 |
20050203248 | Zheng et al. | Sep 2005 | A1 |
20050215693 | Wang et al. | Sep 2005 | A1 |
20050228074 | Wang et al. | Oct 2005 | A1 |
20050282956 | Bohm et al. | Dec 2005 | A1 |
20060084722 | Lin et al. | Apr 2006 | A1 |
20060173115 | Wang et al. | Aug 2006 | A1 |
20060173130 | Wang et al. | Aug 2006 | A1 |
20060235128 | Bohm et al. | Oct 2006 | A1 |
20070135579 | Obrecht et al. | Jun 2007 | A1 |
20070142550 | Wang et al. | Jun 2007 | A1 |
20070149649 | Wang et al. | Jun 2007 | A1 |
20070161754 | Bohm et al. | Jul 2007 | A1 |
20070185273 | Hall et al. | Aug 2007 | A1 |
20070196653 | Hall et al. | Aug 2007 | A1 |
20080145660 | Wang et al. | Jun 2008 | A1 |
20080149238 | Kleckner et al. | Jun 2008 | A1 |
20080160305 | Wang et al. | Jul 2008 | A1 |
20080286374 | Wang et al. | Nov 2008 | A1 |
20080305336 | Wang et al. | Dec 2008 | A1 |
20090005491 | Warren et al. | Jan 2009 | A1 |
20090048390 | Wang et al. | Feb 2009 | A1 |
Number | Date | Country |
---|---|---|
2127919 | Mar 1995 | CA |
3434983 | Apr 1986 | DE |
4241538 | Jun 1994 | DE |
0143500 | Jun 1985 | EP |
0255170 | Feb 1988 | EP |
0265142 | Apr 1988 | EP |
0265145 | Apr 1988 | EP |
0322905 | Jul 1989 | EP |
0352042 | Jan 1990 | EP |
0472344 | Feb 1992 | EP |
0540942 | May 1993 | EP |
0590491 | Apr 1994 | EP |
0742268 | Nov 1996 | EP |
1031605 | Aug 2000 | EP |
1099728 | May 2001 | EP |
1134251 | Sep 2001 | EP |
1273616 | Jan 2003 | EP |
1321489 | Jun 2003 | EP |
1783168 | May 2007 | EP |
2099645 | Mar 1972 | FR |
01279943 | Jan 1989 | JP |
2191619 | Jul 1990 | JP |
2196893 | Aug 1990 | JP |
05132605 | May 1993 | JP |
06248017 | Sep 1994 | JP |
7011043 | Jan 1995 | JP |
08199062 | Aug 1996 | JP |
2000-514791 | Nov 2000 | JP |
2003-095640 | Apr 2003 | JP |
2006-072283 | Mar 2006 | JP |
2006-106596 | Apr 2006 | JP |
2007-304409 | Nov 2007 | JP |
9104992 | Apr 1991 | WO |
9704029 | Feb 1997 | WO |
9853000 | Nov 1998 | WO |
0075226 | Dec 2000 | WO |
0187999 | Nov 2001 | WO |
02031002 | Apr 2002 | WO |
02081233 | Oct 2002 | WO |
02100936 | Dec 2002 | WO |
03032061 | Apr 2003 | WO |
03085040 | Oct 2003 | WO |
2004058874 | Jul 2004 | WO |
2006069793 | Jul 2006 | WO |
2008079276 | Jul 2008 | WO |
2008079807 | Jul 2008 | WO |
2009006434 | Jan 2009 | WO |
Number | Date | Country | |
---|---|---|---|
20070142559 A1 | Jun 2007 | US |