CN106496398B - A kind of environment-friendly preparation method thereof of cationic polyvinylidene fluoride film material - Google Patents
A kind of environment-friendly preparation method thereof of cationic polyvinylidene fluoride film material Download PDFInfo
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- CN106496398B CN106496398B CN201610938386.XA CN201610938386A CN106496398B CN 106496398 B CN106496398 B CN 106496398B CN 201610938386 A CN201610938386 A CN 201610938386A CN 106496398 B CN106496398 B CN 106496398B
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- 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
- C08F214/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
- C08F214/18—Monomers containing fluorine
- C08F214/22—Vinylidene fluoride
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- 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
- C08F2/00—Processes of polymerisation
- C08F2/12—Polymerisation in non-solvents
- C08F2/16—Aqueous medium
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Abstract
The present invention relates to a kind of environment-friendly preparation method thereofs of cationic vinylidene separation membrane material,It is the copolymer synthetic technology formed based on a kind of water/oil two-phase interface free radical polymerization,Redox reaction occurs with potassium peroxydisulfate at normal temperatures exclusively with a kind of double type cation surface activating initiator,It is repeated several times and generates free radicals and cause vinylidene and the independent polymerisation of dimethyl diallyl ammonium chloride at interface,Two kinds of segments are serially connected by initiator molecule,Constitute segmented copolymer,Experiments have shown that when the pH value of aqueous media is in 4.0~4.5 range,The rate of charge of monomer and the ratio of components of copolymer are very consistent,The content of dimethyl diallyl ammonium chloride segment is adjustable in 5~25wt.% ranges in copolymer,The polymeric reaction condition of this pattern is mildly controllable,Low energy consumption,Without other organic solvents and emulsifier,Products pure,Comply fully with the requirement of Green Chemistry.
Description
Technical field
The present invention relates to synthesis of polymer material technical field, especially a kind of cationic polyvinylidene fluoride film material
Environment-friendly preparation method thereof, the copolymer are a kind of amphipathic nature polyalcohols can be used for separation membrane material preparation, its preparation method symbol
Close the requirement of Green Chemistry.
Background technology
It is a small amount of fluorine-containing with other that Kynoar (PVDF) resin is primarily referred to as vinylidene fluoride homopolymer or vinylidene
The copolymer of vinyl monomer, PVDF resins have both the characteristic of fluororesin and resins for universal use, good resistant to chemical etching except having
Property, heat-resisting quantity, oxidative resistance, weatherability, outside resistance to ray radiation performance, also have piezoelectricity, dielectricity, pyroelectricity etc. special
Performance, is the big product that yield is at the second place in current fluoro-containing plastic, and global annual capacity is more than 4.3 ten thousand tons.Kynoar
Film is that PVDF solution is fabricated in supporting layer by vanguard technology, and resistance to pH range is wide, is good gas, organic liquid
The miillpore filter of filtering.It is mainly used for the processing of the industrial wastewaters such as electrophoretic coating, printing and dyeing, plating and municipal sewage, in food work
The useful species such as the highly effective recycling protein of energy, starch in the wastewater treatment of industry, are mainly used for removing bacterium in water supply
And the pretreatment that ultra-pure water is produced.Kynoar (PVDF) is a kind of hydrophobic polymer, in seperation film preparation process
It needs that polyvinylpyrrolidone is added to increase the hydrophily of film, but this hydrophilic polymer can in use gradually
It is lost in, the hydrophily of film is caused to be deteriorated, contamination resistance declines.Therefore it is to realize that membrane material is permanent for the chemical modification of PVDF
One scheme of property hydrophiling.
Vinylidene is a lower monomer of polymerization activity, is generally seldom copolymerized with functional olefinic monomer, thus
Greatly limit the space that chemical modification is realized by copolymerization means.Water/oil two-phase interface polymerization technique can fundamentally be broken
This technical barrier is solved, so that the synthesis of various vinylidene fluoride copolymers materials is become convenient, realizes that the key of interfacial polymerization is
Using double type cation surface activating initiator as shown in Figure 1, which is in the interface of water phase and oil phase, it can be incited somebody to action
The polymerisation of water/oil two-phase is connected in series, and this amphiphilic trimethylamine molecule can be with water-soluble K2S2O8Constitute oxygen
Change reduction initiating system, free radical formed on the adjacent carbon atom of nitrogen-atoms by repeated Intramolecular electron transfer,
Interface free radical can cause the polymerisation of oil phase, can also cause the polymerisation of water phase, as long as adding in a certain order
Enter different monomers, so that it may polymerize with independent cause, not interfere with each other, because the reactive species of polymerisation both are from the same initiation
Agent molecule, so the polymer chain formed is connected together, basic principle as shown in Fig. 2, it should be noted that, in order to
Ensure the smooth implementation of copolyreaction, the combination of comonomer must be with the structure of initiator and the pH value of aqueous media
Match.Polydimethyl diallyl ammonium chloride is a kind of water-soluble polymer, and carries positive charge, passes through above-mentioned polymerization side
Formula can link together hydrophobic Kynoar chain with hydrophilic polydimethyl diallyl ammonium chloride, and formation carries
The amphipathic nature polyalcohol of positive charge, overcomes the disadvantage of Kynoar hydrophily deficiency completely, this copolymer be very suitable for
The PVDF of commodity is used in mixed way, and the copolymer of different attribute is selected according to different requirements, membrane material modified to reach
Purpose.
According to the present invention is a case of this novel polymerizable mode, and initiator used is a kind of special construction
Double type cation surface activating initiator, it is in K2S2O8It under effect, can generate free radicals at normal temperatures, not other
The polymerization for causing hydrophobic vinylidene and hydrophilic dimethyl diallyl ammonium chloride in the presence of surfactant respectively, obtains
It is difficult to the segmented copolymer synthesized to other polymerization means, and the preparation method of this material complies fully with Green Chemistry
Standard：Normal-temperature reaction, low energy consumption, does not use organic solvent, without other surfactants.
Invention content
Primary technical problem to be solved by this invention is to provide a kind of water/oil two-phase interface radical polymerization technique, this
The characteristics of kind polymerization technique, is generated free radicals in specific water/oil two-phase interface under room temperature, and different olefinic monomers is caused
It polymerize according to separate mode, and can be concatenated a variety of segments by initiator molecule, forms new copolymer.
Another technical problem to be solved by this invention is to provide double type necessary to above-mentioned interface free radical polymerization
Cation surface activating initiator, the function of its existing surfactant, and Redox Initiator body can be formed with potassium peroxydisulfate
System, causes various polymerizing olefin monomers at normal temperatures.
Another technical problem to be solved by this invention is in the way of above-mentioned interface free radical polymerization and specific
Surface active initiator provides a kind of specific side preparing vinylidene/dimethyl diallyl ammonium chloride segmented copolymer
Method.
1, technical solution is used by the present invention solves primary technical problem：A kind of water/oil two-phase interface radical polymerization
Conjunction technology, for basic principle as shown in Fig. 2, it is different from the general polymerisation caused in water phase or oil phase, it is a kind of
It is positioned at the free radical initiation method of two-phase interface, the polymerisation complete independently of water phase or oil phase can be made, and is serially connected in one kind
On initiator.
It is beneficial that the polymerization of different monomers can by homopolymerization mode respectively complete independently, do not interfere with each other, it is final to obtain
Be more blocks copolymer；
It is beneficial that the composition of copolymer can be controlled simply by the rate of charge of monomer, avoid because of list
Body activity difference influences caused by being formed on copolymer；
It is beneficial that the monomer of various different attributes can be formed copolymer by this technology, to synthesize various uses
Copolymer provide extensive feasibility.
2, technical solution is used by the present invention solves another technical problem：A kind of double type cation surface activating
Initiator, molecular structure are as shown in Figure 1.
It is beneficial that this initiator can be located in the interface of water/oil two-phase, the energy with emulsive oily monomer
Power, thus no longer need that other emulsifiers are added, after causing polymerization, it just becomes a part for polymer material, no
Emulsifier leakage problem is will produce, will not be had an adverse effect to the performance of polymer material；
It is beneficial that the tertiary amine in initiator can at normal temperatures be reacted with potassium peroxydisulfate, interface free radical is generated, it is double
To aqueous and oiliness monomer polymerization is caused, segmented copolymer is synthesized by multiphase concatenation；
It is beneficial that this initiator can be generated free radicals repeatedly on α-carbon by constantly aoxidizing nitrogen-atoms,
It shows the characteristics of its chain of rings causes, can flexibly control polymerisation, various of monomer is made to be polymerize in a certain order, very
Be conducive to the MOLECULE DESIGN of polyolefin macromolecular material.
3, technical solution is used by the present invention solves another technical problem：Utilize above-mentioned double type cationic surface
Active initiator prepares the specific method of vinylidene/dimethyl diallyl ammonium chloride segmented copolymer, characterization step
It is：1) double type cation surface activating initiator is soluble in water, concentration is generally in 2.5~3.0 ‰ ranges, the use of initiator
Amount is usually the 2.5~3.0% of vinylidene weight, adjusts the pH value of aqueous solution to faintly acid, ensures double type cation form
Then aqueous solution is placed in closed high-pressure reactor, then is passed through nitrogen into reactor by the emulsifying capacity of face active initiator
Gas is to exclude internal air；2) vinylidene fluoride monomers are injected into reactor, the pressure of 5.5MPa is kept under room temperature, makes list
Body is in liquid, and potassium peroxydisulfate saturated solution is added after being sufficiently stirred, and (amount of potassium peroxydisulfate, which is generally, puts into the 1.0 of monomer weight
~1.5%), about 5~polymerisation generation after ten minutes, and polymer dispersion liquid is quickly formed, system temperature and pressure have
Risen, gradually fallen after rise with cooling effect, the polymerisation of first stage generally continues 1~1.5 hour；3) release reaction
50% aqueous solution of second of monomer diallyldimethylammonChloride Chloride, dimethyl is added in extra gas in kettle under normal pressure
The weight ratio of diallyl ammonium chloride and vinyl chloride is in 0.05~0.3 range, and the Kynoar particle formed is substantially not
Become, after second batch potassium peroxydisulfate is added, polymerisation restarts, and the dispersibility of particle becomes more preferably because of hydrophilic enhancing,
Generally in 2~5 μ ms, reaction continues 1~2 hour, finally obtains well dispersed amphipathic copolymer, product the diameter of grain
Composition can be controlled by the rate of charge of monomer.
It is beneficial that since free radical only generates at interface, oiliness monomer concentration is high, thus polymerisation is fast, turns
Rate is high, and monomer can be sequentially added into polymerization process, is very easy to the composition and structure of control polymer；
It is beneficial that the polymerisation of vinylidene can carry out at normal temperatures, as long as taking away what polymerization was released in time
Heat would not generate excessively high pressure, thus improve the safety coefficient of operation；
It is beneficial that it is added without other organic solvents, dispersant or perfluoro emulsifier in entire polymerization process,
Exacting terms is not needed, the requirement of Green Chemistry is complied fully with.
The advantage of the invention is that：1) the independent equal of various of monomer may be implemented using new interface radical polymerization technique
Coalescence mutually concatenates, and is easy to control the composition and structure of polymer；2) reactivity ratio is avoided, monomer physical difference is copolymerized tradition
The restriction of method is conducive to prepare a greater variety of olefin copolymers, has widened high molecular material development space significantly；3) it polymerize
Reaction condition is mildly controllable, low energy consumption, does not have to other organic solvents and emulsifier, and products pure complies fully with Green Chemistry
It is required that.
Specific implementation mode
Present invention is further described in detail with reference to embodiments.
Prepared by vinylidene/dimethyl diallyl ammonium chloride copolymer is carried out by following operating procedure：
A. 1.5g double type cation surface activating initiators are dissolved in 500mL water, concentration is generally 2.5~3.0 ‰
Range, the dosage of initiator are usually the 2.5~3.0% of vinylidene weight, by the way that different amounts of acetic acid and sodium phosphate is added
Mixture adjusts pH value (pH=9~10 of aqueous solution；PH=7~8；PH=4.0~4.5), aqueous solution is placed in closed
In high-pressure reactor, nitrogen is led into reactor to exclude internal air；
B. 55g oil-soluble monomers vinylidene (boiling point under 0.1MPa is -84 DEG C) is injected into reactor, under room temperature
The pressure for keeping 5.5MPa, makes monomer be in liquid, and the potassium peroxydisulfate saturated solution (amount one of potassium peroxydisulfate is added after being sufficiently stirred
As be the 1.0~1.5% of input monomer weight), about 5~after ten minutes polymerisation occur, and quickly form polymer point
Dispersion liquid, system temperature and pressure are risen, and are gradually fallen after rise after supercooling, and the polymerisation of first stage generally continues 1~
1.5 hour；
C. gas pressure extra in reaction kettle is discharged, different amounts of second of monomer dimethyl, two allyl is added under normal pressure
Ammonium chloride (50% aqueous solution), the weight ratio of dimethyl diallyl ammonium chloride and vinylidene is in 0.05~0.3 range,
Kynoar particle through formation is basically unchanged, and after second batch potassium peroxydisulfate is added, polymerisation restarts, point of particle
Scattered property becomes more preferably, and generally in 2~5 μ ms, reaction continues 1~2 hour, finally obtains well dispersed two diameter of particle
Parent's property copolymer obtains pulverulent solids, drying for standby, product dissolves in many organic with fully washing again after methanol extraction
Solvent, convenient for further preparing various seperation films.
Product analysis：It is weighed than the consistency with copolymer ratio of components by comparing monomeric charge after polymerisation twice
The actual effect of the initiator is possible to deposit after polymerization to the reaction mixture methanol extraction of unit volume, removing every time
Small molecule monomer, weighed after the obtained washed drying of polymer, just obtain polymer output, polymerization for the first time obtains
The yield M of Kynoar1, the yield M of copolymer is obtained after second of polymerization1+M2, thus extrapolate two kinds in copolymer
The quality ratio of components M of block2/M1, and rate of charge m2/m1The mass ratio for two kinds of monomers being added in exactly testing.Acquired reality
Test that the results are shown in Figure 3.
The control of product composition：Experimental data shows the association of itself and initiator of the polymerisation heavy dependence of vinylidene
The same sex, this concertedness are mainly influenced by PH values, so the pH of the relationship and polymerisation medium of rate of charge and ratio of components
There is very strong dependence in value, when pH value is in 4.0~4.5 range, the relationship of rate of charge and ratio of components is substantially right
On linea angulata position slightly on the upper side, the reason of being upwardly deviated from is caused by the volatility of vinylidene is too strong, and polymerization is always every time
Have marginally that monomer exists in gaseous form, so affect conversion ratio, but the polymerisation of two kinds of monomers is all in general
Than more thoroughly, the efficiency of initiation of initiator is higher.The M when pH value is in 7~8 range2/M1With m2/m1Correlation curve is obviously to right
Deviate above linea angulata, the main reason is that vinylidene fluoride polymerization is not thorough, when second comonomer dimethyl diallyl ammonium chloride is thrown
Enter amount it is larger when, its conversion ratio also declines, therefore the curve starts to deflect down again, and close to diagonal line, but two kinds at this time
The conversion ratio of monomer is all undesirable.When pH value is 9~10, the upward substantial deviation diagonal line of the curve illustrates in alkaline condition
The emulsifying capacity of lower double type cation surface activating initiator dies down, it is poor with the concertedness of vinylidene, and efficiency of initiation is not
Height, the conversion ratio of monomer also degradation, but in second step polymerization, the polymerization of dimethyl diallyl ammonium chloride also occurs
Problem, conversion ratio decline always with the increase of second comonomer, so curve deflects downwards again, and intersect with diagonal line, show
Right latter two condition is undesirable.Experiment proves that when pH value is less than 4, the protonation of initiator leads to redox again
Reaction is obstructed, and the trigger rate of initiator is substantially reduced, and is unfavorable for the progress of polymerisation, so the desired pH of medium should be controlled
System is easy to control the composition of copolymer by rate of charge in this way in 4.0~4.5 ranges.
Description of the drawings
The chemical constitution of Fig. 1 double type cation surface activating initiators.
The basic principle of Fig. 2 water/oil two-phase interface free radical polymerization.
The influence that the pH value of Fig. 3 media forms copolymer.
Claims (1)
1. a kind of preparation method of vinylidene/dimethyl diallyl ammonium chloride copolymer, it is characterised in that use following knot
The cation surface activating initiator of structure：
The preparation method of the vinylidene/dimethyl diallyl ammonium chloride copolymer, operating procedure are followed successively by：
1) cation surface activating initiator is soluble in water, concentration is controlled in 2.5~3.0 ‰ ranges, cation surface activating
The dosage of initiator is the 2.5~3.0% of vinylidene weight, adjusts the pH value of aqueous solution in 4~4.5 ranges, then by water
Solution is placed in closed high-pressure reactor, then logical nitrogen is to exclude internal air；
2) oil-soluble monomer vinylidene is injected into reactor, the pressure of 5.5MPa is kept under room temperature, monomer is made to be in liquid
State, is added potassium peroxydisulfate saturated solution after being sufficiently stirred, the dosage of potassium peroxydisulfate is put into monomer weight 1.0~1.5%, 5
~polymerisation generation after ten minutes, and polymer solids dispersion liquid is quickly formed, polymerisation continues 0.5~1 hour；
3) gas pressure extra in reaction kettle is discharged, second of monomer diallyldimethylammonChloride Chloride, dimethyl diene is added
The weight ratio of propyl ammonium chloride and vinylidene is in 0.05~0.3 range, and after second batch potassium peroxydisulfate is added, polymerisation can be after
It is continuous to carry out, and continue 1~2 hour, well dispersed granular disintegration is finally obtained, after being washed and dried with methanol extraction, is obtained
To pulverulent solids product.
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