Ethylene and styrene multi-block copolymer and preparation method thereof
阅读说明：本技术 一种乙烯与苯乙烯多嵌段共聚物及其制备方法 (Ethylene and styrene multi-block copolymer and preparation method thereof ) 是由 刘波 崔冬梅 于 2020-12-29 设计创作，主要内容包括：本发明提供一种乙烯与苯乙烯多嵌段共聚物及其制备方法,涉及高分子共聚物领域。该共聚物由乙烯/苯乙烯交替序列、间规聚苯乙烯序列及聚乙烯序列组成；其中,苯乙烯结构单元的含量在30mol％至70mol％之间,所述共聚物的玻璃化转变温度为20℃至70℃,熔点在120-140℃和/或200-260℃之间,该共聚物的结构式如式1所示。本发明还提供一种乙烯与苯乙烯多嵌段共聚物的制备方法,该方法将乙烯和苯乙烯在催化体系作用下,通过链穿梭聚合方法将乙烯/苯乙烯交替序列、间规聚苯乙烯序列、聚乙烯短序列可控的结合在一条分子链上,得到乙烯与苯乙烯多嵌段共聚物。(The invention provides an ethylene and styrene multi-block copolymer and a preparation method thereof, relating to the field of high-molecular copolymers. The copolymer consists of an ethylene/styrene alternating sequence, a syndiotactic polystyrene sequence and a polyethylene sequence; wherein, the content of the styrene structural unit is between 30 mol% and 70 mol%, the glass transition temperature of the copolymer is between 20 ℃ and 70 ℃, the melting point is between 120-140 ℃ and/or 200-260 ℃, and the structural formula of the copolymer is shown as formula 1. The invention also provides a preparation method of the ethylene and styrene multi-block copolymer, and the method catalyzes ethylene and styrene in a catalytic mannerUnder the action of the system, an ethylene/styrene alternating sequence, a syndiotactic polystyrene sequence and a polyethylene short sequence are controllably combined on a molecular chain by a chain shuttling polymerization method to obtain the ethylene and styrene multi-block copolymer.)
1. An ethylene and styrene multi-block copolymer, characterized in that the copolymer consists of alternating sequences of ethylene/styrene, syndiotactic polystyrene sequences and polyethylene sequences; wherein, the content of the styrene structural unit is between 30 mol% and 70 mol%, the glass transition temperature of the copolymer is between 20 ℃ and 70 ℃, the melting point is between 120 ℃ and 140 ℃ and/or 200 ℃ and 260 ℃, and the structural formula of the copolymer is shown as formula 1:
in formula 1, x, y, z, m and n are integers greater than 1.
2. The multi-block copolymer of ethylene and styrene as claimed in claim 1, wherein the number average molecular weight of the copolymer is 5,000-500,000 and the molecular weight distribution is less than 5.
3. The process for the preparation of an ethylene and styrene multiblock copolymer according to claim 1, comprising:
carrying out copolymerization reaction on ethylene and styrene under the action of a catalytic system to obtain an ethylene and styrene multi-block copolymer;
the catalytic system comprises a rare earth metal complex with a restricted geometric configuration shown in a formula I, a single metallocene rare earth metal complex shown in a formula V, a cocatalyst and a chain transfer reagent;
wherein R is1Selected from cyclopentadienyl and derivatives thereof shown in formula II, indenyl and derivatives or fluorenyl and derivatives thereof shown in formula IV, wherein the cyclopentadienyl and the derivatives are shown in formula II;
R2、R3each independently selected from one of hydrogen, methyl, ethyl, isopropyl, tert-butyl, phenyl, 2, 6-dimethylphenyl, 4-methylphenyl, mesityl, 2, 6-diisopropylphenyl, 2,4, 6-triisopropylphenyl or 2, 6-di-tert-butylphenyl, R2And R3May be the same or different;
R4is C1-C20 alkyl, C1-C20 alkylsilyl, C1-C20 alkylamino, borohydride or allyl;
ln represents rare earth metal selected from Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu;
y is coordinated Lewis base;
z is C, Si, Ge;
m＝1～2；n＝0～2；q＝1～3；
wherein R is4Is C1-C20 alkyl, C1-C20 alkylsilyl, C1-C20 alkylamino, borohydride or allyl;
R5、R6、R7、R8and R9Are identical or different from each other and are each independently selected from hydrogen atoms, havingAlkyl of 1 to 10 carbon atoms, aryl of C6 to C20, silyl of C1 to C14, or R5And R6Are linked to each other to form a ring, or R6And R7Are linked to each other to form a ring, or R8And R9Are connected with each other to form a ring;
e is O, S or N-R; the R is selected from methyl, benzene ring or substituted benzene ring;
ln represents rare earth metal selected from Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu;
y is coordinated Lewis base; n is 0 to 2.
4. The method of claim 3, wherein the cocatalyst is an organoborate.
5. The process according to claim 4, wherein the organoboron salt is [ Ph [ ] -3C][B(C6F5)4]、[Ph3C][BPh4]、[PhNMe2H][BPh4]、[PhNMe2H][B(C6F5)4]、BPh3Or B (C)6F5)3。
6. The method of claim 3, wherein the chain transfer agent is an alkylaluminum, an alkylaluminum hydride, an alkylaluminum chloride, such as trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisopropylaluminum, triisobutylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum, triphenylaluminum, tri-p-tolylaluminum, tribenzylaluminum, ethyldibenzylaluminum, ethyldi-p-tolylaluminum, or diethylbenzylaluminum; dimethylaluminum chloride, diethylaluminum chloride, ethylaluminum dichloride, dimethylaluminum hydride or diethylzinc.
7. The method of claim 3, wherein the ratio of the total molar amount of the constrained geometry rare earth metal complex represented by formula I and the single metallocene rare earth metal complex represented by formula V to the molar amount of the organoboron compound is in the range of 0.5:1 to 10: 1; the ratio of the total molar amount of constrained geometry rare earth metal complex represented by formula (I) and the metallocene rare earth metal complex represented by formula (V) to the molar amount of chain transfer agent is in the range of 2:1 to 300: 1; the ratio of the molar amounts of constrained geometry rare earth metal complex represented by formula I and the metallocene rare earth metal complex represented by formula V is (1-9): (1-9).
8. The method of claim 3, wherein the copolymerization is carried out in a medium selected from one or more of aliphatic saturated hydrocarbon, aromatic hydrocarbon, aryl halide and cycloalkane.
9. The method of claim 3, wherein the temperature of the copolymerization is 0-150 ℃ and the time is 1min-7 days.
10. The method for preparing an ethylene-styrene multiblock copolymer according to claim 3, wherein the copolymerization is carried out under an ethylene pressure of 1 to 10 atm.
Technical Field
The invention relates to the field of high-molecular copolymers, in particular to an ethylene and styrene multi-block copolymer and a preparation method thereof.
Background
The ethylene and styrene productivity in China is the first in the world, and the materials obtained by copolymerizing the ethylene and the styrene have excellent mechanical properties and good compatibility with most high polymer materials, so that the research on ethylene/styrene copolymerization is widely concerned at the beginning of this century. However, the reaction performance of ethylene and styrene is greatly different, and the traditional Ziegler-Natta catalyst is difficult to realize the copolymerization of the ethylene and the styrene; the titanium metal complex can catalyze the copolymerization of ethylene/styrene to only obtain a copolymer (similar random copolymer) with discretely distributed styrene structural units; the scandium metal complexes reported catalyze the copolymerization of ethylene/styrene without exception to give ethylene/styrene copolymers containing crystalline syndiotactic polystyrene sequences. Therefore, it is very challenging to control the sequence distribution of the two structural units of ethylene and styrene in the copolymer.
In 2006, Tao chemical Arrioa et al, USA, used a ternary system consisting of bisphenol imine zirconium metal complex/pyridine imine hafnium metal complex/diethyl zinc to catalyze copolymerization of ethylene and alpha olefin, and prepared an olefin multi-block copolymer (OBC product name: Infuse) with alternately arranged hard segment (crystalline segment with low alpha-olefin content) and soft segment (amorphous segment with high alpha-olefin content) through cross-chain transfer of alkyl zinc chain transfer agent between active centers of two catalysts, and proposed a concept of chain shuttling polymerization. Subsequently, "chain shuttling" polymerization has attracted research interest as a strategy for the one-pot synthesis of multi-block polymers. Unfortunately, the related studies are slow in progress, almost exclusively based on the development of the Arriola system. Until 2012, a subject group of the petitioner professor of the Japan institute of science and research adopts a ternary system consisting of half-metallocene scandium metal alkyl complex/amidino scandium alkyl complex/triisobutyl aluminum to catalyze the copolymerization of styrene and isoprene, so as to prepare the multi-block copolymer of syndiotactic polystyrene and 3,4 polyisoprene. In 2014, a subject group of Zinck professor of the university of Ricel, France adopts a ternary system consisting of mono-cyclopentadienyl lanthanum borohydride/handle-shaped bis-cyclopentadienyl neodymium borohydride/butyl ethyl magnesium to catalyze the copolymerization of isoprene and styrene, and the multi-block copolymer of atactic polystyrene and trans-1, 4 polyisoprene is prepared. Therefore, the monomers for realizing chain shuttling polymerization are limited, and the development of new monomers has important significance for developing new materials.
Disclosure of Invention
The invention aims to provide an ethylene and styrene multi-block copolymer and a preparation method thereof, wherein the copolymer combines an ethylene/styrene alternating sequence, a syndiotactic polystyrene sequence and a polyethylene short sequence on a molecular chain in a controllable manner by a chain shuttling polymerization method.
The invention firstly provides an ethylene and styrene multi-block copolymer, which consists of an ethylene/styrene alternating sequence, a syndiotactic polystyrene sequence and a polyethylene sequence; wherein, the content of the styrene structural unit is between 30 mol% and 70 mol%, the glass transition temperature of the copolymer is between 20 ℃ and 70 ℃, the melting point is between 120 ℃ and 140 ℃ and/or 200 ℃ and 260 ℃, and the structural formula of the copolymer is shown as formula 1:
in formula 1, x, y, z, m and n are integers greater than 1.
Preferably, the number average molecular weight of the copolymer is 5,000-500,000, and the molecular weight distribution is less than 5.
The invention also provides a preparation method of the ethylene and styrene multi-block copolymer, which comprises the following steps:
carrying out copolymerization reaction on ethylene and styrene under the action of a catalytic system to obtain an ethylene and styrene multi-block copolymer;
the catalytic system comprises a rare earth metal complex with a restricted geometric configuration shown in a formula I, a single metallocene rare earth metal complex shown in a formula V, a cocatalyst and a chain transfer reagent;
wherein R is1Selected from the group consisting of cyclopentadienyl groups of formula II and derivatives thereof, indenyl groups of formula III andderivatives thereof or fluorenyl groups and derivatives thereof represented by formula IV;
R2、R3each independently selected from one of hydrogen, methyl, ethyl, isopropyl, tert-butyl, phenyl, 2, 6-dimethylphenyl, 4-methylphenyl, mesityl, 2, 6-diisopropylphenyl, 2,4, 6-triisopropylphenyl or 2, 6-di-tert-butylphenyl, R2And R3May be the same or different;
R4is C1-C20 alkyl, C1-C20 alkylsilyl, C1-C20 alkylamino, borohydride or allyl;
ln represents rare earth metal selected from Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu;
y is coordinated Lewis base;
z is C, Si, Ge;
m＝1～2；n＝0～2；q＝1～3；
wherein R is4Is C1-C20 alkyl, C1-C20 alkylsilyl, C1-C20 alkylamino, borohydride or allyl;
R5、R6、R7、R8and R9Are the same or different from each other and are each independently selected from a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group of C6-C20, a silyl group of C1-C14, or R5And R6Are linked to each other to form a ring, or R6And R7Are linked to each other to form a ring, or R8And R9Are connected with each other to form a ring;
e is O, S or N-R; the R is selected from methyl, benzene ring or substituted benzene ring;
ln represents rare earth metal selected from Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu;
y is coordinated Lewis base; n is 0 to 2.
Preferably, the cocatalyst is an organoboron salt.
Preferably, the organoboron salt is [ Ph ]3C][B(C6F5)4]、[Ph3C][BPh4]、[PhNMe2H][BPh4]、[PhNMe2H][B(C6F5)4]、BPh3Or B (C)6F5)3。
Preferably, the chain transfer agent is an alkylaluminum, an alkylaluminum hydride, an alkylaluminum chloride, such as trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisopropylaluminum, triisobutylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum, triphenylaluminum, tri-p-tolylaluminum, tribenzylaluminum, ethyldibenzylaluminum, ethyldi-p-tolylaluminum, or diethylbenzylaluminum; dimethylaluminum chloride, diethylaluminum chloride, ethylaluminum dichloride, dimethylaluminum hydride or diethylzinc.
Preferably, the ratio of the total molar amount of the constrained geometry rare earth metal complex represented by formula I and the metallocene rare earth metal complex represented by formula V to the molar amount of the organoboron compound is in the range of 0.5:1 to 10: 1; the ratio of the total molar amount of constrained geometry rare earth metal complex represented by formula (I) and the metallocene rare earth metal complex represented by formula (V) to the molar amount of chain transfer agent is in the range of 2:1 to 300: 1; the ratio of the molar amounts of constrained geometry rare earth metal complex represented by formula I and the metallocene rare earth metal complex represented by formula V is (1-9): (1-9).
Preferably, the copolymerization is carried out in a medium selected from one or more of aliphatic saturated hydrocarbons, aromatic hydrocarbons, aryl halides or cycloalkanes.
Preferably, the temperature of the copolymerization reaction is 0-150 ℃ and the time is 1min-7 days.
Preferably, the copolymerization is carried out under an ethylene pressure of 1 to 10 atm.
The invention has the advantages of
The invention provides an ethylene and styrene multi-block copolymer and a preparation method thereof, wherein an ethylene/styrene alternating sequence, a syndiotactic polystyrene sequence and a polyethylene short sequence are controllably combined on a molecular chain through cross chain transfer between a chain transfer agent alkyl aluminum and two active centers, so that the multi-block ethylene/styrene copolymer with a GPC curve in unimodal distribution is obtained. Depending on the ratio of constrained geometry rare earth metal complex to metallocene constrained geometry rare earth metal complex, the resulting polymer may have one glass transition temperature and one melting point, or two glass transition temperatures and two melting points, or one glass transition temperature and two melting points, which are caused by the difference in length of the different sequences in the polymer. Therefore, the regulation and control of each segment of sequence of the multi-block polymer are realized by regulating the proportion of the constrained geometry rare earth metal complex and the single metallocene constrained geometry rare earth metal complex. When the copolymer has two melting points with larger difference, the corresponding crystalline phases can be respectively used as a reversible phase and a stationary phase, and the copolymer has potential application in the aspect of high-temperature shape memory materials.
Drawings
FIG. 1 is a DSC chart of sample 1 of a copolymer obtained in example 1 of the present invention.
FIG. 2 shows a copolymer sample 3 obtained in example 3 of the present invention13C NMR spectrum.
FIG. 3 is a GPC curve of copolymer sample 4 obtained in example 4 of the present invention.
Detailed Description
The invention firstly provides an ethylene and styrene multi-block copolymer, which consists of an ethylene/styrene alternating sequence, a syndiotactic polystyrene sequence and a polyethylene sequence;
wherein the content of styrene structural units is between 30 mol% and 70 mol%, preferably between 35 mol% and 65 mol%;
the glass transition temperature of the copolymer is 20-70 ℃, preferably 25-65 ℃, the melting point is between 120-140 ℃ and/or 200-260 ℃, preferably between 120-135 ℃ and/or 200-250 ℃, and the structural formula of the copolymer is shown as formula 1:
in formula 1, x, y, z, m and n are integers greater than 1.
According to the present invention, the number average molecular weight of the copolymer is preferably 5,000-500,000, more preferably 5,000-400,000; the molecular weight distribution is preferably less than 5, more preferably less than 3.
The invention also provides a preparation method of the ethylene and styrene multi-block copolymer, which comprises the following steps:
carrying out copolymerization reaction on ethylene and styrene under the action of a catalytic system to obtain an ethylene and styrene multi-block copolymer; the method specifically comprises the following steps:
a) dispersing a catalytic system in an organic solvent to obtain a catalyst solution;
the catalytic system comprises a rare earth metal complex with a restricted geometric configuration shown in a formula I, a single metallocene rare earth metal complex shown in a formula V, a cocatalyst and a chain transfer reagent;
wherein R is1Selected from cyclopentadienyl and derivatives thereof shown in formula II, indenyl and derivatives or fluorenyl and derivatives thereof shown in formula IV, wherein the cyclopentadienyl and the derivatives are shown in formula II;
R2、R3each independently selected from one of hydrogen, methyl, ethyl, isopropyl, tert-butyl, phenyl, 2, 6-dimethylphenyl, 4-methylphenyl, mesityl, 2, 6-diisopropylphenyl, 2,4, 6-triisopropylphenyl or 2, 6-di-tert-butylphenyl, R2And R3May be the same or different;
R4is C1-C20 alkyl, C1-C20 alkylsilyl, C1-C20 alkylamino, borohydride or allyl; the alkyl of C1-C20 is preferably CH3、CH2CH3、CH(CH3)2、C(CH3)3The C1-C20 alkylsilyl group is preferably CH2SiMe2Or CH (SiMe)3)2The alkylamino group of C1-C20 is preferably CH2(o-C6H4(NMe2) Borohydride group) of boronPreferably BH4The allyl group is preferably 1,3-C3H5、1,3-C3H4(Me)、1,3-C3H3(SiMe3)2；
Ln represents rare earth metal selected from Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu;
y is coordinated Lewis base, preferably tetrahydrofuran, pyridine and ethylene glycol dimethyl ether; z is C, Si, Ge;
m＝1～2；n＝0～2；q＝1～3。
the preferred structure of the constrained geometry rare earth metal complex shown in formula I is shown as 1,3, 5, 7 and 9:
the single metallocene rare earth metal complex shown in the formula V is as follows:
wherein R is4Is C1-C20 alkyl, C1-C20 alkylsilyl, C1-C20 alkylamino, borohydride or allyl; the alkyl of C1-C20 is preferably CH3、CH2CH3、CH(CH3)2、C(CH3)3The C1-C20 alkylsilyl group is preferably CH2SiMe2Or CH (SiMe)3)2The alkylamino group of C1-C20 is preferably CH2(o-C6H4(NMe2) Borohydride is preferably BH)4The allyl group is preferably 1,3-C3H5、1,3-C3H4(Me)、1,3-C3H3(SiMe3)2；
R5、R6、R7、R8And R9Are identical or different from one another and are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group of C6-C20, a silyl group of C1-C14,or R5And R6Are linked to each other to form a ring, or R6And R7Are linked to each other to form a ring, or R8And R9Are connected with each other to form a ring;
e is O, S or N-R; the R is selected from methyl, benzene ring or substituted benzene ring;
ln represents rare earth metal selected from Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu;
y is coordinated Lewis base, preferably tetrahydrofuran, pyridine and ethylene glycol dimethyl ether; z is C, Si, Ge;
m＝1～2；n＝0～2；q＝1～3。
the preferred structures of the constrained geometry rare earth metal complexes shown in the formula I are shown as 2,4,6, 8 and 10:
according to the invention, the preparation method of the rare earth metal complex with the restricted geometric configuration shown in the formula I refers to a Chinese patent with the application number of CN201210020478.1, and the preparation method of the single metallocene rare earth metal complex shown in the formula V refers to a Chinese patent with the application number of CN 201310478190.3.
According to the invention, the cocatalyst is preferably an organoboron salt, more preferably [ Ph [ ]3C][B(C6F5)4]、[Ph3C][BPh4]、[PhNMe2H][BPh4]、[PhNMe2H][B(C6F5)4]Or BPh3Or B (C)6F5)3。
According to the invention, the chain transfer agent is preferably an alkylaluminum, alkylaluminum hydride, alkylaluminum chloride, such as trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisopropylaluminum, triisobutylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum, triphenylaluminum, tri-p-tolylaluminum, tribenzylaluminum, ethyldibenzylaluminum, ethyldi-p-tolylaluminum or diethylbenzylaluminum; dimethylaluminum chloride, diethylaluminum chloride, ethylaluminum dichloride, dimethylaluminum hydride or diethylzinc.
According to the invention, the ratio of the total molar amount of the constrained geometry rare earth metal complex represented by formula I and the metallocene rare earth metal complex represented by formula V to the molar amount of the organoboron compound is in the range of 0.5:1 to 10: 1; the ratio of the total molar amount of constrained geometry rare earth metal complex represented by formula (I) and the metallocene rare earth metal complex represented by formula (V) to the molar amount of chain transfer agent is in the range of 2:1 to 300: 1; the ratio of the molar amounts of constrained geometry rare earth metal complex represented by formula I and the metallocene rare earth metal complex represented by formula V is (1-9): (1-9), more preferably (5-9): (1-5).
b) And catalyzing ethylene/styrene by using the catalyst solution to perform copolymerization reaction to obtain the ethylene/styrene multi-block copolymer.
According to the invention, the copolymerization is carried out in a medium, preferably selected from one or more of aliphatic saturated hydrocarbons, aromatic hydrocarbons, aryl halides or cycloalkanes.
According to the invention, the temperature of the copolymerization is preferably from 0 to 150 ℃, more preferably from 20 to 120 ℃, and the time is preferably from 1min to 7 days, more preferably from 1min to 24 h.
According to the present invention, the copolymerization reaction is preferably carried out under an ethylene pressure of 1 to 10atm, more preferably 1 to 8 atm.
The present invention is described in further detail below with reference to specific examples, in which the starting materials are all commercially available.
Example 1
In a glove box, toluene (30mL) and styrene (1.82g,) were charged to a reaction flask with magnetons. Rare earth metal complexes 1 and 2 (20 mol in total; rare earth metal complex 1: rare earth metal complex 2: 9:1), [ Ph3C][B(C6F5)4](18.4mg) and triisobutylaluminum (0)24g,1.7mmol/g toluene solution) was prepared into a 5mL toluene solution, which was charged into an ampoule. The ampoule was connected to the reaction flask via a rubber tube. The reaction flask was taken out of the glove box and placed in an oil bath pan at 40 ℃. The atmosphere in the reaction flask was replaced three times with ethylene. The catalyst solution in the ampoule was then rapidly added to a toluene solution of styrene to initiate polymerization. Ethylene (1bar) was passed continuously through the polymerization. After reaching the specified polymerization time for 10min, the polymerization was terminated by adding acidified ethanol to the reaction flask. The mixture was poured into ethanol and allowed to settle. The polymer was isolated by filtration and placed in an oven at 20 ℃ and dried under reduced pressure to constant weight. Sample 1 was obtained.
The DSC chart of sample 1 prepared in example 1 is shown in FIG. 1.
Example 2
In a glove box, toluene (60mL) and styrene (3.60g,) were charged into a reaction flask with magnetons. Rare earth metal complexes 3 and 4 (20 mol in total; rare earth metal complex 3: rare earth metal complex 4: 8:2), [ Ph3C][B(C6F5)4](36.8mg) and triisobutylaluminum (0.24g,5.1mmol/g toluene solution) were prepared as a 5mL toluene solution, which was charged in an ampoule. The ampoule was connected to the reaction flask via a rubber tube. The reaction flask was taken out of the glove box and placed in an oil bath pan at 40 ℃. The atmosphere in the reaction flask was replaced three times with ethylene. The catalyst solution in the ampoule was then rapidly added to a toluene solution of styrene to initiate polymerization. Ethylene (1bar) was passed continuously through the polymerization. After 1h of the indicated polymerization time, the polymerization was terminated by adding acidified ethanol to the reaction flask. The mixture was poured into ethanol and allowed to settle. The polymer was separated by filtration and placed in an oven at 60 ℃ and dried under reduced pressure to constant weight. Sample 2 was obtained.
Example 3
In a glove box, hexane (60mL) and styrene (3.60g,) were charged into a reaction flask with magnetons. Rare earth metal complexes 5 and 6 (20 mol in total; rare earth metal complex 5: rare earth metal complex 6: 7:3), [ Ph3C][B(C6F5)4](36.8mg) and triisobutylaluminum (0.24g,5.1mmol/g toluene solution) were prepared as a 5mL toluene solution, which was charged in an ampoule. The ampoule was connected to the reaction flask via a rubber tube. The reaction flask was taken out of the glove box and placed in an oil bath pan at 40 ℃. The atmosphere in the reaction flask was replaced three times with ethylene. The catalyst solution in the ampoule was then rapidly added to a toluene solution of styrene to initiate polymerization. Ethylene (1bar) was passed continuously through the polymerization. After 2 days at the indicated polymerization time, the polymerization was terminated by adding acidified ethanol to the reaction flask. The mixture was poured into ethanol and allowed to settle. The polymer was isolated by filtration and placed in an oven at 40 ℃ and dried under reduced pressure to constant weight. Sample 3 was obtained.13The C NMR spectrum is shown in FIG. 2.
Example 4
In a glove box, chlorobenzene (60mL) and styrene (3.60g,) were charged into a reaction flask with magnetons. Rare earth metal complexes 7 and 8 (20 mol in total; rare earth metal complex 7: rare earth metal complex 8: 5), [ Ph [ Ph ] ]3C][B(C6F5)4](36.8mg) and triisobutylaluminum (0.24g,5.1mmol/g toluene solution) were prepared as a 5mL toluene solution, which was charged in an ampoule. The ampoule was connected to the reaction flask via a rubber tube. The reaction flask was taken out of the glove box and placed in an oil bath pan at 40 ℃. The atmosphere in the reaction flask was replaced three times with ethylene. The catalyst solution in the ampoule was then rapidly added to a toluene solution of styrene to initiate polymerization. Ethylene (1bar) was passed continuously through the polymerization. After 4 days at the indicated polymerization time, the polymerization was terminated by adding acidified ethanol to the reaction flask. The mixture was poured into ethanol and allowed to settle. Filtering to separate out polymerThe mixture was put into an oven at 80 ℃ and dried under reduced pressure to constant weight. Sample 4 was obtained. The GPC curve of sample 4 is shown in FIG. 3.
Example 5
In a glove box, hexane (60mL) and styrene (3.60g,) were charged into a reaction flask with magnetons. Rare earth metal complexes 9 and 10 (20 mol in total; rare earth metal complex 9: rare earth metal complex 10: 5), [ Ph [ Ph ] ]3C][B(C6F5)4]A toluene solution (5 mL) was prepared from (18.4mg) and triisobutylaluminum (2.40g,1.7mmol/g toluene solution), and charged in an ampoule. The ampoule was connected to the reaction flask via a rubber tube. The reaction flask was taken out of the glove box and placed in an oil bath pan at 40 ℃. The atmosphere in the reaction flask was replaced three times with ethylene. The catalyst solution in the ampoule was then rapidly added to a toluene solution of styrene to initiate polymerization. Ethylene (1bar) was passed continuously through the polymerization. After 1min of reaching the specified polymerization time, the polymerization was terminated by adding acidified ethanol to the reaction flask. The mixture was poured into ethanol and allowed to settle. The polymer was separated by filtration and placed in an oven at 100 ℃ and dried under reduced pressure to constant weight. Sample 5 was obtained.
TABLE 1
In Table 1fStRepresenting the content of styrene.
The nuclear magnetic diagram of an analysis sample shows that the rare earth metal complex with the restricted geometric configuration shown in the formula I catalyzes ethylene/styrene copolymerization to obtain an ethylene/styrene alternating sequence, the glass transition temperature of the ethylene/styrene alternating sequence is about 30 ℃, and the melting point of the ethylene/styrene alternating sequence is about 127 ℃; the single metallocene rare earth metal complex shown in the formula V catalyzes ethylene styrene to copolymerize to obtain a block copolymer of syndiotactic polystyrene and polyethylene short sequences, the glass transition temperature of the block copolymer is adjustable between 48 and 76 ℃, and the melting point of the block copolymer is adjustable between 210 and 250 ℃. Through the cross chain transfer between the chain transfer agent alkyl aluminum and two active centers, the ethylene/styrene alternating sequence, the syndiotactic polystyrene sequence and the polyethylene short sequence are controllably combined on a molecular chain (figure 2), and the multi-block ethylene/styrene copolymer (figure 3) with a GPC curve in unimodal distribution is obtained. Depending on the ratio of constrained geometry rare earth metal complex to metallocene constrained geometry rare earth metal complex, the resulting polymer may have one glass transition temperature and one melting point, or two glass transition temperatures and two melting points, or one glass transition temperature and two melting points, which are caused by the difference in length of the different sequences in the polymer. Therefore, the regulation and control of each segment of sequence of the multi-block polymer are realized by regulating the proportion of the constrained geometry rare earth metal complex and the single metallocene constrained geometry rare earth metal complex. This is otherwise difficult to achieve.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：己烯共聚高密度聚乙烯拉丝料冷凝态生产工艺