CN103396654A - Cellulose nano-fibril/epoxy resin composite film preparation method - Google Patents

Cellulose nano-fibril/epoxy resin composite film preparation method Download PDF

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CN103396654A
CN103396654A CN2013103593451A CN201310359345A CN103396654A CN 103396654 A CN103396654 A CN 103396654A CN 2013103593451 A CN2013103593451 A CN 2013103593451A CN 201310359345 A CN201310359345 A CN 201310359345A CN 103396654 A CN103396654 A CN 103396654A
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epoxy resin
mierocrystalline cellulose
cellulose
solution
wood powder
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李大纲
潘佳
陈振东
李雪婷
胡月
薛莹莹
李明珠
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Nanjing Forestry University
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Nanjing Forestry University
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Abstract

The present invention relates to a cellulose nano-fibril/epoxy resin composite film preparation method, which comprises the following steps: a) purifying a raw material; 2) carrying out chemical treatments, wherein the chemical treatments comprise three acid treatments and two alkali treatments; 3) carrying out physical treatments, wherein the physical treatments contain three mechanical treatments such as ultrasonic crushing, grinding through a grinding machine, and a high pressure homogenizer; 4) preparing a fiber nano-fibril film; and 5) preparing a cellulose nano-fibril/epoxy resin composite material. According to the present invention, the prepared cellulose nano-fibril has a diameter of 20-80 nm, the nano-cellulose film has a tensile strength of 159.2 MPa and an elastic modulus of 7.3 GPa, transmittance of the nano-cellulose resin film is 86%, the cellulose film has characteristics of high length-diameter ratio, uniform fiber diameter distribution, good thermal stability, and a thermal expansion coefficient of 14 ppm/K, and the film can be widely applied in the fields of high temperature resistance flexible electronic device light transmittance films, optically transparent functional paper, gas barrier packaging materials, tissue engineering materials, filtration membrane materials and the like.

Description

A kind of preparation method of Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane
Technical field
The present invention relates to be a kind of cellulose nano-fibrous/preparation method of epoxy resin composite membrane, belong to technical field of composite materials.
Background technology
The preparation of nano-cellulose fibril can sum up several preparation methods basically:
(1) physical method is by using ultrasonic grinder, homogenizer, shredder or high-pressure homogeneous instrument are processed wood pulp, can draw a kind of Mierocrystalline cellulose of primitive fiber, obtained nano level cancellated Mierocrystalline cellulose, its Fibre diameter, can be for the preparation of transparent high-strength nano mixture between 10 ~ 100nm.
(2) to prepare the main method of nano-cellulose be the hydrolysis of acid or alkali to the chemical treatment plant materials, also comprises with tensio-active agent or biological enzyme and processing.Generally by after wood fibre pre-treatment bleaching, the fiber of sulphuric acid soln after hydrolysis bleaching under specified temp with the finite concentration quality, add the water coolant stopped reaction and carry out centrifugal, Reduplicated will precipitate after stirring suspension centrifugal, until become jellied suspension.In the clear liquid of suspension, obtained desired nano-cellulose fibril.
(3) also having a kind of method is enzymolysis, M. people (the European Polymer Journal such as Henriksson, 2007 (43): 3434 – 3441) utilize cellulase optionally enzymolysis fall unbodied Mierocrystalline cellulose and remaining part cellulose crystals, by transglycosylase, in mode chemical and enzyme modification simultaneously, activate the nano cellulose crystal surface, thereby be unlikely to destroy primitive fibril and internal crystal structure in the cellulose crystals finishing.
(4) other also has the methods such as artificial synthesis of nano Mierocrystalline cellulose and electrospun nanofibers cellulose fiber, artificial synthesis the most easily regulates and controls structure, crystal formation and the size distribution etc. of nano-cellulose, and electrostatic spinning can be made thin fiber with artificial method.But these two kinds of methods are imperfection also, also in the middle of research.
Epoxy resin refers in molecule a class organic high molecular compound that contains two or more epoxide groups, and their relative molecular mass is all little.The molecular structure of epoxy resin is in molecular chain, to contain active epoxide group to be feature, and epoxide group can be positioned at end, the centre of molecular chain, or structure circlewise, and epoxy resin is a kind of thermoplastic oligomer, poor performance.Except as the stablizer of polyvinyl chloride etc., few of direct use value, but owing in the epoxy resin molecular structure, containing active epoxide group, they can form with polytype solidifying agent generation crosslinking reaction the superpolymer of three-dimensional net structure insoluble, that do not melt, present the performance of a series of excellences, thereby have remarkable practical value.
Before epoxy resin is uncured, be the linear structure of thermoplasticity, can not directly use, must add second component, cross-linking and curing reaction occurs at a certain temperature, could generate the cancellated superpolymer of operational build, the second component that adds is called solidifying agent.The kind of epoxy curing agent is more, adds numerous promotor, properties-correcting agent, additive etc., can carry out diversified combination and assembly.Thereby can obtain the cured article of very wide range of properties excellence.
Because pure epoxy resin has high crosslinking structure, thereby it exists matter crisp, and shock strength is low, and is easy to crack, is difficult to meet the requirement of growing engineering, thereby limited its further application.Along with the appearance of nano composite material and the formation of nanometer composite technology, the study on the modification work of epoxy resin enters a brand-new period, and the various performances of Epoxy-Nanocomposites all are improved.Also have in addition rigidity nano-particle toughening epoxy resin, utilize exactly the physics and chemistry method, the trickle inorganic particulate that induces one in epoxy resin is the common method of modified epoxy.Rigid particles is when viscous deformation, and tensile stress can suppress the expansion of matrix resin crackle effectively, has absorbed simultaneously portion of energy, plays toughening effect.Nanometer inorganic filler commonly used comprises titanium dioxide, zinc oxide, calcium carbonate, aluminum oxide, silicate etc.Dendriform molecule Toughening Modification of Epoxy utilizes a kind of take small molecules as vegetative point exactly, and a series of molecular masses that reaction repeated obtains constantly increase by progressively controlling, the compound of similar.Its chemical structure is along with reaction is carried out increasing to the surrounding radiation, and final formation has the globosity of internal cavities and a large amount of branches.
characteristics due to nano-cellulose, it can be used as the wild phase of epoxy resin, nano-cellulose is added in epoxy resin epoxy resin is carried out to enhancing modified, nanofibrils with nanoscale can form sufficient splicing interface with epoxy resin, be dispersed in epoxy resin, nanoparticle has less size and larger specific surface area, can form the reactive force greater than Van der Waals force with the polar group of epoxy resin, cause tiny crack, endergonic effect is stronger, thereby the resistance to impact shock of matrix material, tensile strength, the performance quality such as Young's modulus and second-order transition temperature all improves than former epoxy resin, also can in toughness reinforcing, improve storage modulus and the heat-drawn wire of resin.
Shimazaki(Biomacromolecules, 2007,8 (9): 2976-2978) use epoxy resin and Mierocrystalline cellulose nanofibrils to prepare transparent material.Aqueous cellulosic (0.2wt%) is used the membrane filter vacuum filtration, and aperture is 0.1 μ m.After filtration, obtain sheet material at 55 ℃ of dry 48h, immerse subsequently in epoxy-resin systems, epoxy-resin systems comprises solidifying agent, epoxy resin and promotor.The sheet material of dipping is clipped between sheet glass, 120 ℃ of curing 3h, and 140 ℃ of curing 2h are to obtain nanofibrils/epoxy resin composite material.The final thickness that obtains matrix material is 70 μ m, and fibre content is 58wt%.Prepared matrix material still has the transparency of height by the transmitted spectrum proof, and the epoxy resin composite material that adds nanofibrils confirms that after overheat test its heat conductivity is higher than the pure epoxy resin matrix material, and thermal expansivity also drops to 23ppm/k from the 87ppm/k of pure epoxy resin matrix material.
Summary of the invention
That the present invention proposes is a kind of preparation method of Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane, its purpose is intended to overcome the deficiency that prior art exists, by acid treatment, remove xylogen wherein, alkaline purification removes hemicellulose, and the Mierocrystalline cellulose nanofibrils is isolated in the hydrochloric acid treating part.Cellulosic fibre solution uses shredder, and the diameter that ultrasonic grinder and high pressure homogenizer are opened the Mierocrystalline cellulose nanofibrils after fibre by cellulosic fibre solution machinery generally is distributed between 20-80nm, and length-to-diameter ratio surpasses 1000; Prepared Mierocrystalline cellulose nano thin-film is laminate structure, and is entangled to each other between fiber.
Technical solution of the present invention: a kind of preparation method of Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane comprises the steps:
1) feedstock purification;
2) chemical treatment, contain three acid treatment and secondary alkaline purification;
3) physical treatment, contain ultrasonic grinding, and shredder grinds, three kinds of mechanical treatments of high-pressure homogeneous instrument;
4) preparation of fiber yarn nanofibrils film;
5) preparation of Mierocrystalline cellulose nanofibrils to epoxy resin composite material.
Advantage of the present invention:1) by acid treatment, remove xylogen wherein, alkaline purification removes hemicellulose, and the Mierocrystalline cellulose nanofibrils is isolated in the hydrochloric acid treating part.Cellulosic fibre solution uses shredder, and the diameter that ultrasonic grinder and high pressure homogenizer are opened the Mierocrystalline cellulose nanofibrils after fibre by cellulosic fibre solution machinery generally is distributed between 20-80nm, and length-to-diameter ratio surpasses 1000; 2) prepared Mierocrystalline cellulose nano thin-film is laminate structure, and is entangled to each other between fiber.The compound reticulated structure of this stratiform makes the tensile strength of cellulosefilm can reach 159.2MPa, and Young's modulus is 7.3GPa.The transmittance of cellulosefilm reaches 86%, can use as strengthening transparent material.Meanwhile, cellulosefilm is because of its high length-diameter ratio, and distribution of fiber diameters is even, causes the Heat stability is good of film, and its thermal expansivity (CTE) is 14ppm/K; 3) the content maximum of Mierocrystalline cellulose nanofibrils in the prepared nano compound film of Mierocrystalline cellulose nanofibrils reinforced epoxy can be reached to 90%, tensile strength and Young's modulus can reach 112.6MPa and 4.9GPa respectively; Transmittance can reach 87.7%, with pure epoxy resin, compares and only is lost in 5%; Thermal expansivity (CTE) is 17ppm/K.4) the prepared nano composite material of the present invention can have wide practical use in fields such as high-temperature flexible electrical equipment light-transmissive film, optical transparency functional paper, gas-barrier wrapping material, tissue engineering material, filter membrane material.5) utilize the wild phase of nano-cellulose as epoxy resin, can carry out toughening modifying to epoxy resin, make the performance quality such as resistance to impact shock, tensile strength, Young's modulus and second-order transition temperature of epoxy resin composite material all than former epoxy resin, improve, make its range of application more extensive, high performance nano-cellulose/epoxy resin composite material can be applied in the aspects such as space flight, automobile, senior sports goods.Technique is simple, and cost is low, and rice fibril film reinforced epoxy, improve its tensile strength and Young's modulus.
The accompanying drawing explanation
Fig. 1 is cellulose nano-fibrous preparation method's process flow diagram.
Fig. 2 is the Mierocrystalline cellulose nanofibrils electromicroscopic photograph after ultrasonic 60min, (a) 1000 times, and (b) 10000 times.
Fig. 3 is the Mierocrystalline cellulose nanofibrils electromicroscopic photograph that grinds after 30 times, (a) 1000 times, and (b) 10000 times.
Fig. 4 grinds+Mierocrystalline cellulose nanofibrils electromicroscopic photograph after ultrasonic, and (a) 2000 times, (b) 10000 times.
Fig. 5 is the Mierocrystalline cellulose nanofibrils electromicroscopic photograph after grinding+homogeneous, (a) 1000 times, and (b) 20000 times.
Fig. 6 is the Mierocrystalline cellulose nanofibrils diameter Distribution figure after different physical mechanicals are processed, (a) after ultrasonic 60min, (b) after grinding 30 times, (c) grind+ultrasonic after, and (d) after grinding+homogeneous.
Fig. 7 is the transmittance comparison diagram that different physical mechanical modes make Mierocrystalline cellulose nanofibrils film.
Fig. 8 is the Mierocrystalline cellulose infrared spectrogram after different physical methods are processed.
Embodiment
Embodiment 1, as Fig. 1,
Prepare Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane,
Feedstock purification: the poplar wood powder is screened with 60 ~ 70 mesh sieve, then carry out Benzene-ethanol extraction (v/v=2:1) and remove grease and other wood powder impurity in wood powder, after extracting, use the absolute ethanol washing wood powder, remove toluene unnecessary in wood powder, wood powder after washing subsequently is positioned in culture dish, 24 ~ the 48h that ventilates in stink cupboard, treat the wood powder drying, gets the chemical treatment of appropriate wood powder for the preparation of the Mierocrystalline cellulose nanofibrils.
Chemical treatment:
acid treatment for the first time: get the 10g wood powder and be dissolved in 390ml distilled water, add the 3.9g Textone, be configured to concentration and be 1% sodium chlorite solution, simultaneously, add the acetic acid of 3 ~ 4ml to guarantee to become acidic conditions in wood powder solution, this moment, the pH value of solution was 4 ~ 5 after tested, this acid treatment process is in order to remove the xylogen composition in xylon, mixing solutions is 75 ℃ of heated sealed 1h in magnetic stirring apparatus, in mixing solutions, again add afterwards the 3.9g Textone, 3 ~ 4ml acetic acid, to guarantee that wood powder can react completely in enough Textones, this adds the treating processes of appropriate Textone and acetic acid to repeat 6 times every 1h, the color that can see wood powder in the acid treatment process becomes white by yellow,
Alkaline purification for the first time: for the first time after acid treatment, use distilled water to utilize vacuum filter filtration washing wood powder, the wood powder washing is extremely neutral, configure subsequently 400ml concentration and be 3% potassium hydroxide solution, be sealed in magnetic stirring apparatus and heat 90 ℃ of stirrings 2 hours, use afterwards the distilled water wash wood powder to neutral, this alkaline purification process is in order to remove the hemicellulose in xylon, the colloid in remaining starch and xylon;
Acid treatment for the second time: wood powder is added in the sodium chlorite solution of 1% concentration, add 3 ~ 4ml acetic acid to keep the acidic conditions of solution, 1h is stirred in 75 ℃ of sealings of heating in magnetic stirring apparatus afterwards, and this process repeats 3 times, and acid treatment for the second time is in order to remove the xylogen in xylon fully;
Alkaline purification for the second time: after acid treatment for the second time, it is neutral that wood powder is washed into, is added to 400ml concentration and is in 6% potassium hydroxide solution, heat 90 ℃ of stirring 2h, this process and the same meaning of acid treatment process for the second time are in order to remove more completely the hemicellulose in xylon;
Acid treatment for the third time namely, the salt acid treatment: after alkaline purification, wood powder is distilled water washing to neutral, adding 390ml concentration is 1% hydrochloric acid soln, 85 ℃ of stirring 2h of heating in magnetic stirring apparatus, the salt acid treatment is in order by xylon, to divide fine fibril, in order at physical mechanical, process the fibrillation process better, it is 0.5 ~ 1% solution that the xylon of finally finishing dealing with adds distilled water to be configured to mass concentration.
Physical treatment, comprise
Physics is ultrasonic: the xylon solution that configures is used to vegetable cell ultrasonic grinder ultrasonic 60min in ice-water bath, and temperature remains at 30 ℃ of following ultrasonication, finally obtains ultrasonic cellulose solution;
Shredder grinds: the xylon solution that configures is used to the stone mortar shredder, rotating speed is 1800rpm, regulating the distance between metate on shredder is 0.01 ~ 0.02mm, because be the wet grinding method, water has played and has made the grinding stone contact, but be unlikely the grinding stone effect broken because close contact generates heat, and grind 10 ~ 30 times, finally obtain the milled fibre cellulose solution;
High-pressure homogeneous instrument: after grinding, use high-pressure homogeneous instrument to carry out further physics fragmentation to resulting cellulose solution, the pressure of 1000 ~ 1500pa is set, homogeneous 30 ~ 60min, finally obtain uniform nanofiber cellulose solution, and this solution is light blue, transparent
After physical mechanical is opened fibre, the Mierocrystalline cellulose nanofibrils solution that obtains preparing: namely
1. ultrasonic 60min; 2. grind 30 times; 3. after grinding 30 times, follow ultrasonic 60min; 4. grind 30 times and follow afterwards homogeneous 60min.
Prepare fiber yarn nanofibrils film, the Mierocrystalline cellulose nanofibrils solution that is 1 wt% by prepared concentration uses vacuum apparatus to filter, the filter membrane aperture of using is 0.2 μ m, diameter is 9cm, the diameter of Büchner funnel is 12cm, in Büchner funnel, first pad the filter paper of one deck 12cm diameter, again filter membrane fully is attached to the filter paper surface, use the wetting filter membrane of distilled water, and open vacuum pump make filter membrane fully with the Büchner funnel laminating, pour Mierocrystalline cellulose nanofibrils solution in Büchner funnel filtering coating at this moment; After film forming, filter membrane is taken out, on the filter membrane surface with cellulose membrane, paste a filter membrane again, be clipped in the middle of two-layer facial tissue, the facial tissue that will accompany afterwards the nano-cellulose film is positioned in book, Air drying 9 ~ 10h; Existing eighty per cant drying of nano-cellulose film this moment, subsequently the nano-cellulose film on filter membrane surface is slowly opened, for guaranteeing that the nano-cellulose film can not fit tightly the situation of taking off not open that causes with filter membrane in ensuing drying, the nano-cellulose film of opening is placed in to two filter membranes again, be clipped in facial tissue in the middle of two iron plates that are positioned in vacuum drying oven, 60 ℃ of high-pressure drying 24 ~ 48h, iron plate 2 ~ 3kg.
Prepare the Mierocrystalline cellulose nanofibrils to epoxy resin composite material, include
(1) preparation of pure epoxy resin film: extracting epoxy resin is in culture dish, add subsequently solidifying agent polyetheramine D230, the part by weight of epoxy resin and solidifying agent is 100/30, the mixture of epoxy resin and solidifying agent is hand operated mixing 10min at normal temperatures, make the reduced viscosity of epoxy resin, stirring fully reflects solidifying agent and epoxy resin, the epoxy resin that is stirred and curing agent mixture are placed in to 60 ℃ of baking ovens and heat 10min, further reduce the viscosity of epoxy resin composition, then be placed on the sheet glass with tetrafluoroethylene paper, in 60 ℃ of baking ovens, heat 40 ~ 60min, make epoxy resin and curing agent mixture present at this moment a kind of gel state, cover afterwards another piece and have equally the sheet glass of tetrafluoroethylene paper, in baking oven, be heating and curing after 24h and take out, matrix material is opened from tetrafluoroethylene paper, the thickness of this laminated film is 200 ~ 400 μ m, or
(2) with the standby Mierocrystalline cellulose nanofibrils of miscible legal system/epoxy resin laminated film: by Mierocrystalline cellulose nanofibrils solution after lyophilize, form dry nano-cellulose, get nano-cellulose, put into 50 ~ 60ml acetone, for Mierocrystalline cellulose is dispersed in acetone soln, just mixing solutions is placed in ultrasonic instrument, ultrasonic 30min under 30 ℃, at this moment, ultrasonic by in the dispersion of the nano-cellulose of freeze-drying and acetone soln, this mixing solutions is stirring at normal temperature 3 ~ 4h in magnetic stirrer, extracting epoxy resin adds in the acetone mixing solutions and stirs 4h subsequently, be placed in 60 ℃ of baking oven 3 ~ 5h, make acetone volatilize fully, add afterwards solidifying agent polyetheramine D230, the part by weight of epoxy resin and solidifying agent is 100/30, hand operated mixing mixture 5 ~ 10min, be positioned over the viscosity that reduces epoxy resin composition in baking oven, then mixture is poured on the sheet glass with tetrafluoroethylene paper, in 60 ℃ of baking ovens, heat 40 ~ 60min, make mixture present at this moment a kind of gel state, cover afterwards another piece and have equally the sheet glass of tetrafluoroethylene paper, in baking oven, be heating and curing after 24h and take out, matrix material is opened from tetrafluoroethylene paper, the thickness of this laminated film is 200 ~ 400 μ m, or
(3) with pickling process, prepare Mierocrystalline cellulose nanofibrils/epoxy resin laminated film: epoxy resin is added in the 60ml acetone soln, stirring at normal temperature 4h in magnetic stirrer, this moment, epoxy resin fully was dissolved in acetone soln, add afterwards the solidifying agent polyetheramine, the ratio of epoxy resin and polyetheramine is 100/30, and this epoxy systems continues stirring at normal temperature 1h in acetone.The Mierocrystalline cellulose nanofibrils for preparing is thin film dipped in the epoxy resin acetone soln, every after by this thin film suspending 50 ℃ of dryings in convection oven, take out afterwards.
The ultrasonic power of the ultrasonic employing of physics is 1000W ~ 1200W.
Resin is epoxy resin E44, and solidifying agent is polyetheramine D230, and after epoxy resin cure, modulus is 1.1GPa.
Embodiment 2
The variation to xylon solution appearance form in the chemical acid alkali treating processes:
In xylon, contain Mierocrystalline cellulose, hemicellulose and the large element of xylogen three, in timber, content of cellulose is about 40% ~ 50%, around protofibril, exist hemicellulose, around cellulosic, exist xylogen, therefore, Mierocrystalline cellulose only just can be observed after delignification, and protofibril only just can be observed after hydrolysis of hemicellulose.In order to extract as much as possible Mierocrystalline cellulose wherein, adopt chemical treatment that hemicellulose and xylogen are removed.Can find out that Mierocrystalline cellulose sinks to the vial bottom always in chemical treating process, it is mainly that the xylogen in wood powder is gone out that Textone is processed, and after acid treatment, the color that can find out significantly wood powder becomes white by yellow originally, this is illustrated in acid treatment process for the first time, and most of xylogen has been removed.Potassium hydroxide treatment is subsequently gone out the hemicellulose in xylon, in treating processes, it is yellow that the wood powder solution of potassium hydroxide is, this moment, hemicellulose was hydrolyzed gradually, secondary acid treatment, alkaline purification and salt acid treatment do not make the aqueous solution of xylon that any macromorphologic variation occurs, and its internal microstructure is observed by scanning electron microscope and Fourier's infrared tester.
Embodiment 3
Cellulose solution after physical mechanical is processed again after chemical acid alkali:
Xylon is after chemical treatment, and remaining nearly all is comprised of Mierocrystalline cellulose, also needs physical mechanical to process Mierocrystalline cellulose is dispersed into to micro-fibril.Micro-fibril is not a kind of new material, and it is the elementary cell of cell wall skeleton material.When forming cell walls, the cellulosic molecule of many chains is arranged in molecular grouping (micelle) regularly, by molecular grouping, further combined with the structure unit that becomes biologically, is called micro-fibril.The polymerization of many micro-fibrils can become visible macrofibril under opticmicroscope, Mierocrystalline cellulose.Wood powder is after chemical treatment, and color bleaches and nearly all is deposited in the bottom of vial, and this is to contain too much aggregate in the Mierocrystalline cellulose due to mechanical dispersion not, and cellulosic density is greater than water, so sink to the bottom always.Through 1000W after ultrasonic 60 minutes, there is the part Mierocrystalline cellulose to be dispersed into micro-fibril, part micro-fibril suspension is obviously arranged in water, this is owing in cellulosic fibre, having isolated the fibril of a part of nano-scale, the contact area of fibril and moisture increases, and then has formed the cellulose fibril suspension relatively uniformly that distributes.But also have major part to be deposited in the vial top, the most of xylon of this explanation is not separated into the Mierocrystalline cellulose nanofibrils fully.Wood powder solution after chemical treatment is adopted and grinds and the ultrasonic method of using of mixing, xylon after processing is configured to be approximately to the solution of 1wt% concentration, pour the rotating speed of shredder with 1800rpm into, the mill spacing is that 0.01mm grinds 20 ~ 30 times, after grinding postprecipitation 12 ~ 15h, large fiber all is deposited in beaker bottom basically.Get appropriate upper solution, in ice-water bath, carry out the ultrasonic 60min of 1000W, temperature is moderate to be remained on below 30 ℃, and last solution contains part micro-fibril suspension in water, only has a small amount of large fiber at bottom settlings.From macroscopic form, illustrate, grind and add that ultrasonic method makes the Fibre diameter in cellulose solution less, so the transparency of its aqueous solution has improved.
cellulose solution is ground and adds the homogenizing method preparation, its transparency is higher in the cellulose solution of other several physical mechanical treatment processs, this shows, homogeneous makes Mierocrystalline cellulose nearly all be dispersed as uniform micro-fibril, obtained finely dispersed Mierocrystalline cellulose nanofibrils aqueous suspension, the gained fibril is uniformly dispersed in water, the phenomenon of solid-liquid two phase stratification disappears substantially, fibril at this moment is described, and elementary fibrilization is complete, inner fibril majority is separated, greatly improved the contact area of fibril and water, and then formed finely dispersed aqueous suspension.In last handling process, do not needed to use centrifugal means that the large fiber molecule in cellulose solution is separated.
Embodiment 4
In conjunction with through ultrasonic, grind, grind and add ultrasonic, as to grind Mierocrystalline cellulose nanofibrils solution after adding these four kinds different mechanical means of homogeneous and processing microscopic pattern as figure-shown in Figure 5:
Before mechanical treatment, cellulosic length is not destroyed in the chemical physics treating processes, and cellulosic length is in 100 μ m left and right.This is because Mierocrystalline cellulose is comprised of crystallizing field and unformed area, than sulfuric acid and sodium hydroxide, in use the unformed area in Mierocrystalline cellulose is interrupted, thereby Mierocrystalline cellulose is processed into to the process of nanocrystal, Textone used herein, sodium hydroxide and hydrochloric acid remain crystallizing field and noncrystalline domain in removing hemicellulose and xylogen process.Can see that it is all along axial direction due that hydrogen bonded power due to cellulose surface makes Mierocrystalline cellulose in freezing dry process, and every fiber is all very smooth, the bonding that there is no soup compound, in this explanation chemical treating process, hemicellulose and xylogen major part all are removed, and mechanical processes afterwards is from process clean cellulosic fibre, to isolate meticulous Mierocrystalline cellulose nanofibrils.After lyophilize, can see that cellulosic fibre has formed reticulated structure, this reticulated structure can play promoter action in fiber-reinforced resin.
Embodiment 5
(1) according to the sem image of the cellulose fibril after ultrasonic 60min, by the diameter of most of fiber in the image software survey sheet, and draw the associated diameters distribution plan according to data.By image, can be found, the diameter of cellulose fibril mainly is distributed between 200 ~ 250nm, but the part that also has in 20 ~ 200nm diameter range exists, this shows that the cellulosic fibre after ultrasonic opens in fine process also inhomogeneous dispersedly at machinery, also exist more Mierocrystalline cellulose aggregate, this part aggregate after the process of Mierocrystalline cellulose nanofibrils reinforced epoxy in will badly influence the performance of epoxy resin nano composites.So the cellulosic fibre after ultrasonic 60min does not also reach washing of compound needs, also need to carry out supersound process or be aided with grinding, the processing of the physical mechanical methods such as homogeneous.
(2) the cellulose fiber filament diameter after grinding diameter Distribution graph discovery that the cellulose fibril after 30 times obtains according to its sem image and grinding is mainly between 150 ~ 200nm, the Mierocrystalline cellulose of this part accounts for 45% of whole Mierocrystalline cellulose distribution, illustrating to grind also to make the Mierocrystalline cellulose nanofibrils from the Mierocrystalline cellulose aggregate, evenly separating fully, but than the cellulose fibril after ultrasonic, after grinding 30 times, the cellulose fiber filament diameter is thinner, thereby make grinding can obtain larger length-to-diameter ratio, so the cellulose fibril after grinding can after epoxy composite material in bring into play than the better fiber reinforcement effect of the cellulose fibril after ultrasonic.
(3) after grinding and with ultrasonic two kinds of methods, mixing and use, account for 56% of the population distribution scope of the diameter Distribution of cellulose fibril between 100 ~ 150nm, its integral diameter distribution effect also are better than only using the cellulose fibril after prepared by grinding and ultrasonic two kinds of methods.But also have the cellulose fibril of 200 ~ 300nm to exist, probably account for 29% of cellulose fibril total amount, affected the diameter Distribution effect of cellulose fibril, show that the cellulose fibril that grinds after ultrasonic also needs further cavitation process, namely need to continue to use the grinding ultrasonic method, perhaps other thinning processing means, turn to the meticulous fibril of 20 ~ 100nm by the further fibril of Mierocrystalline cellulose aggregate in 100 ~ 150nm scope.
(4) the cellulose fibril diameter Distribution figure that obtains after the grinding homogeneous is as shown in Fig. 8 (d).The gained fibril is evenly distributed between 20 ~ 100nm, has very meticulous uniform cellulose fibril.Prepared cellulose fibril greater than 100nm accounts for 85% of total amount, and greater than the cellulose fibril proportion of 200nm 1% left and right of only having an appointment, this shows and adopts that grinding homogenizes processes the Mierocrystalline cellulose nanofibrils that will obtain uniform high length-diameter ratio.Through grinding homogenization treatment, the Mierocrystalline cellulose nanofibrils is almost completely from the Mierocrystalline cellulose aggregate, peeling off, these high length-diameter ratios, meticulous Mierocrystalline cellulose nanofibrils formation reticulated structure of mutually entwining.After with the epoxy resin recombination process in, these reticulated structures can increase the contact area of cellulose fibril and resin matrix, when strengthening polymkeric substance, can also bring good toughness.
Embodiment 6
Utilize the preparation of 70g printer paper Mierocrystalline cellulose nanofibrils: get a 70g printer paper, claim its weight to be about 9g, shred and add 500ml distilled water, before carrying out chemical treatment, can use stirrer that the shredded paper solution stirring is become to pulp solution.Because in printer paper, be entirely almost Mierocrystalline cellulose, so simple while except the process ratio of xylogen and hemicellulose, preparing wood powder.In pulp solution, add the 5g Textone, 3 ~ 4ml acetic acid, stir 1h in 75 ℃ of water-baths, every 1h, in pulp solution, add the 5g Textone afterwards, 3 ~ 4ml acetic acid, and this acid treatment process repeats twice and gets final product.Distilled water filters acid pulp solution until it becomes neutrality.Adding subsequently concentration is 3% potassium hydroxide solution, remove may be remaining in paper pulp hemicellulose.Finally use the hydrochloric acid soln of 1% concentration that the pulp solution after acid-alkali treatment is purified, make Mierocrystalline cellulose can isolate O-fiber to a certain degree.Cellulose solution after filtration uses shredder to carry out 30 times and grinds.At the bottom of this moment, Mierocrystalline cellulose was different from being deposited in bottle after chemical treatment, but be dispersed in water fully, in order to obtain uniform Mierocrystalline cellulose, and make the Mierocrystalline cellulose diameter less, use high-pressure homogeneous instrument to process the cellulose solution after grinding, obtain final Mierocrystalline cellulose nanofibrils solution.
Embodiment 7
Utilize cotton to prepare the Mierocrystalline cellulose nanofibrils: cotton is the highest in content of cellulose in vegetable fibre, almost reaches 90%.But still can not direct mechanical be processed into the Mierocrystalline cellulose nanofibrils.Same cotton need to, through twice Textone and a potassium hydroxide treatment, remove xylogen and hemicellulose that cotton fiber may exist.The salt acid treatment makes cotton fiber more easily isolate the Mierocrystalline cellulose nanofibrils in physical mechanical is processed, and auxiliary certain milled processed and high-pressure homogeneous processing, just can obtain Mierocrystalline cellulose nanofibrils solution afterwards.
Embodiment 8
After vacuum filtration was made cellulosefilm, existing high-pressure drying 12h at normal temperatures, be placed in loft drier afterwards by the Mierocrystalline cellulose nanofibrils of preparation, and 60 ℃ of dry 24h pressurize.The preparation of epoxy resin impregnated liquid is to get 10g epoxy resin to add in the 60mL acetone soln, stirring at normal temperature 4h.After epoxy resin dissolves fully, add 3g solidifying agent polyetheramine D230, continue stirring at normal temperature 1h, this moment, solidifying agent and epoxy resin were scattered in acetone soln fully.The cellulosefilm of oven dry be impregnated in to 12h in epoxy resin solution, wait for epoxy resin permeable fiber element film inside, take out afterwards, in air dry oven, hang oven dry 24h, obtain cellulose fibril reinforced epoxy matrix material.
Embodiment 9
Different content of cellulose are to Mierocrystalline cellulose nanofibrils/epoxy resin composite material tensile property:
(1) dipping time 24h, when cellulose fiber content is 30%, the tensile strength contrast pure epoxy resin film of epoxy resin nano composites has increased by 153%, Young's modulus is increased to 2.8GPa from 1.2GPa, increased by 133%, result shows that the interpolation of cellulosic fibre has strengthened the tensile property of epoxy resin composite material, and simultaneously elongation at break also is increased to 3.6% from 3.2%, shows that the toughness of epoxy resin composite material has also improved.
(2) dipping time 15h, when cellulose fiber content in epoxy resin nano composites account for 50% the time, the tensile strength of matrix material and Young's modulus are respectively 66.8MPa and 3.4MPa, the epoxy resin nano composites of contrast containing cellulose fiber 30%, tensile strength has improved 45%, and Young's modulus has increased by 43%.
(3) dipping time 10h, when the Mierocrystalline cellulose nanofibrils that adds reach epoxy resin composite material 70% the time, this moment, tensile strength and the Young's modulus of matrix material were brought up to respectively 81.4MPa and 4.1GPa, while contrasting 50% Mierocrystalline cellulose nanofibrils reinforced epoxy matrix material, both have improved respectively 22% left and right.
(4) dipping time 6h, when the Mierocrystalline cellulose nanofibrils when the content of epoxy resin nano composites is 90%, its tensile strength and Young's modulus are up to 116.2MPa and 4.7GPa, and the epoxy resin nano composites that is 70% than cellulose fiber content has improved respectively 43% and 15%.
Embodiment 10
Grind the cellulose solution process supersound process after 30 times, this moment, ultrasonic time was 60min, and temperature is moderate to be remained in the ice-water bath of 30 ℃, the cellulose solution that grinds after solution transparency contrast after ultrasonic is only ground is more transparent, be sky blue, almost cannot see concrete fibre solid particle.The cellulose solution that grinds after 30 times is processed through high-pressure homogeneous instrument, the pressure of this moment is set to 1500bar, the Mierocrystalline cellulose nanofibrils solution that obtains is almost completely transparent, the diameter of the Mierocrystalline cellulose nanofibrils of this explanation after high-pressure homogeneous is little of the almost completely invisible state of naked eyes, and pass through scanning electron microscope analysis, the diameter of Mierocrystalline cellulose nanofibrils is mostly between 50 ~ 80nm at this moment, this explanation, finally grind Mierocrystalline cellulose nanofibrils solution after homogeneous and be exactly our desired final finished.
Embodiment 11
The mechanical property of Mierocrystalline cellulose nanofibrils film
Choose the 70g printer paper as a comparison sample, record its tensile strength and Young's modulus and be respectively 53.9MPa and 3.2GPa.Chemical component in printer paper is substantially also Mierocrystalline cellulose, but Fibre diameter with paper as a comparison, can compare the tensile property impact of Fiber Aspect Ratio on the fiber yarn film through the processing of physical sepn Mierocrystalline cellulose nanofibrils.The tensile strength that cellulosefilm after ultrasonic records and Young's modulus are respectively 75.3MPa and 3.4GPa, with printer paper, compare, and its tensile strength has increased by 40%, and Young's modulus has increased by 6% left and right.Cellulosefilm after ultrasonic is compared with paper, though intensity is improved, but the raising scope is little, Mierocrystalline cellulose after this explanation is ultrasonic does not reach desirable Nano grade, Mierocrystalline cellulose diameter after ultrasonic by its corresponding scanning electron microscope image discovery generally is distributed between 200-300nm, so the ultrasonic cellulosefilm performance that makes does not get a desired effect.Through grinding after 30 times, the tensile strength of cellulosefilm and Young's modulus contrast printer paper, improved respectively 114% and 59%, and this is due in the scanning electron microscope after grinding, the Mierocrystalline cellulose diameter generally is distributed in 150-200nm, and the Mierocrystalline cellulose diameter is less than the Mierocrystalline cellulose diameter after ultrasonic.Than the cellulosefilm after ultrasonic, the tensile strength of the cellulosefilm after grinding and Young's modulus have all increased by 50% left and right.To grind with ultrasonic two kinds of physical methods and be combined and prepare Mierocrystalline cellulose nanofibrils solution, be prepared into tensile strength and the Young's modulus that test obtains after cellulosefilm and be respectively 133.6MPa and 5.7GPa, both compare with printer paper, have all increased by 148% and 78%.In Mierocrystalline cellulose scanning electron microscope image after grinding is ultrasonic, the Mierocrystalline cellulose diameter mainly is distributed between 100-150nm, the Mierocrystalline cellulose that diameter is less makes high 16% left and right of cellulosefilm after the tensile strength of cellulosefilm and modular ratio are only ground, Young's modulus high about 12%.Cellulose solution is ground to rear homogeneous, find that solution becomes transparent by original muddiness, by scanning electron microscope, find that the Mierocrystalline cellulose diameter after homogeneous mainly is distributed between 40-100nm.Cellulosefilm tensile strength and Young's modulus prepared by this Mierocrystalline cellulose nanofibrils are respectively 159.2MPa and 7.3GPa, than printer paper difference high 195% and 128%, with the cellulosefilm after grinding is ultrasonic, compare, and have improved respectively 19% and 28%.These results show, intensity and the Young's modulus of the cellulosefilm after the grinding homogeneous are the highest, grind taking second place after ultrasonic, only the cellulosefilm of process grinding is a little less than grinding ultrasonic cellulosefilm, Mierocrystalline cellulose after ultrasonic, because diameter is too large, is not obvious especially for the tensile strength of its cellulosefilm and the reinforced effects of Young's modulus.This is because Mierocrystalline cellulose length-to-diameter ratio after grinding homogeneous has reached 1000, high length-diameter ratio makes Mierocrystalline cellulose in breaking cellulosic process be difficult for from state of aggregation, being opened, thereby have good mechanical property, and low length-to-diameter ratio fiber, Mierocrystalline cellulose after for example ultrasonic, can be opened at an easy rate, so it is more crisp than the cellulosefilm of high length-diameter ratio, mechanical property is less.
Cellulosefilm tensile property after the different physical methods of table 1 are processed
Embodiment 12
The different number of times that grind
Grinding is that physical mechanical is processed cellulosic main method, by the grinding of Mierocrystalline cellulose being carried out to different number of times, tests afterwards the tensile property of its cellulosefilm for preparing, and determines to grind the impact of number of times on separated fiber element nanofibrils.The data that record are as shown in table 2.The cellulosefilm tensile strength and the Young's modulus that grind after ten times are respectively 72.8MPa and 4.0GPa, grind cellulosefilm after 20 times than grinding ten times, its tensile strength and Young's modulus have improved 29% and 15%, and after grinding 30 times, its tensile property and Young's modulus have increased by 52% and 30%.As can be seen here, along with the increase of grinding number of times, the mechanical property of the cellulosefilm for preparing increases.This is that Ginding process thoroughly disperses these micro-fibrils out because partly isolated cellulose microfibril through chemical treatment Mierocrystalline cellulose later, and the separation degree of the Mierocrystalline cellulose nanofibrils that different grinding number of times brings is different.After grinding 30 times, substantially isolated most of Mierocrystalline cellulose nanofibrils, then ground, the Mierocrystalline cellulose diameter can not change again, but the Mierocrystalline cellulose performance likely reduces.The paper pulp fiber experiment is compared, because before physical mechanical is processed, xylon has been carried out to chemical treatment, so when grinding 10,20,30 times, cellulosic diameter increases along with the increase of grinding number of times.
The tensile property of the cellulose membrane after the different grinding of table 2 number of times
Embodiment 13
Mierocrystalline cellulose nanofibrils film light transmission
(1) different physical mechanical processing modes: (in 400 ~ 800nm), the wavelength of transmitance commonly used is chosen the 600nm place as benchmark, and the transmittance of the Mierocrystalline cellulose nanofibrils film that different physical mechanical modes make after processing as shown in Figure 7 in the visible wavelengths scope.Choose common paper sample as a comparison, paper is also all Mierocrystalline cellulose, to consist of, and can contrast and draw the impact of Mierocrystalline cellulose diameter on the transmittance of Mierocrystalline cellulose nanofibrils film.The transmittance that printer paper records at the 600nm place is 15.4%, cellulosefilm contrast paper after ultrasonic, its transparency has improved 349%, after the Mierocrystalline cellulose diameter reduces, transmitance improves a lot, this be due to the Mierocrystalline cellulose diameter after ultrasonic between 200 ~ 300nm, visual light wavelength is in the 600nm left and right, so the contrast paper, the visible light that the is printing opacity degree that reduces of Mierocrystalline cellulose diameter improves greatly.The transmitance of the cellulosefilm after grinding is than the improve 18.6% after ultrasonic, this be due to the Mierocrystalline cellulose diameter after grinding between 150 ~ 200nm, thinner than the Mierocrystalline cellulose diameter after ultrasonic.And the Mierocrystalline cellulose diameter that grinds after ultrasonic can be observed between 100 ~ 150nm by scanning electron microscope, thus the transmitance of cellulosefilm of grinding ultrasonic rear preparation than the raising after only ultrasonic 22%.Grinding the diameter of the Mierocrystalline cellulose nanofibrils that makes after homogeneous observes and mainly is distributed between 50 ~ 100nm by scanning electron microscope image, so the transmitance of its cellulosefilm is also the highest, reach 86%, than the cellulosefilm after only ultrasonic, increased by 24%, with printer paper, compare, the same is all to consist of Mierocrystalline cellulose, is only the difference of Mierocrystalline cellulose diameter, and its transmitance has improved 458%.These results show that the Mierocrystalline cellulose diameter is thinner, and the transmitance of the cellulosefilm that it makes is higher, and the transmittance of the Mierocrystalline cellulose nanofibrils for preparing after the grinding homogeneous is the highest.
Embodiment 14
Infrared analysis
(1) structural changes of the Mierocrystalline cellulose nanofibrils film for preparing of different physical treatment methods:
Mierocrystalline cellulose nanofibrils solution process vacuum apparatus by the different physical methods that obtain were processed, obtain Mierocrystalline cellulose nanofibrils film.In contrast to wood powder, represent the 1530cm of xylogen -1The stretching vibration peak of phenyl ring at place has disappeared, and characterizes in xylogen-absorption peak 1460 cm of CH2 formation vibration -1Also disappear in the Mierocrystalline cellulose infrared spectrogram after other three physical treatments, these xylogen that show the Mierocrystalline cellulose nanofibrils after physical treatment are removed fully.Represent the stretching vibration absorption peak 1720cm of chromophoric group C=O of the polyxylose of hemicellulose -1In infrared spectrogram after physical treatment, occur obviously to change, still represent charateristic avsorption band 1636 cm of C=O stretching vibration in xylan in hemicellulose -1Still embody to some extent at place, medium-width, intensity a little less than, illustrating in purifying cellulose also residually has a small amount of hemicellulose, this part hemicellulose has played positive effect to the nanofibrils of lignocellulose.And represent cellulosic each characteristic peak, for example 3339 cm -1The stretching vibration of place-OH, 2905 cm -1The stretching vibration of place-CH, 1430cm -1In-plane bending vibration and 897 cm of place-CH2 and-OCH -1The charateristic avsorption bands such as anomeric carbon (C1) vibration at place do not change, and this explanation Mierocrystalline cellulose, in whole treating processes, is all remained by complete.On the whole, chemical structure in Mierocrystalline cellulose nanofibrils after physical mechanical is processed is the same with the cellulose chemistry structure after chemical treatment, xylogen removes substantially fully, hemicellulose is removed by major part, remain a small amount of hemicellulose after separated fiber element nanofibrils in play a driving role.And in different physical mechanicals was processed, three infrared spectrograms were almost completely consistent, and this shows that different physical mechanical treating processess can not make a difference to the chemical structure of Mierocrystalline cellulose nanofibrils.
Those skilled in the art will recognize that; above-mentioned embodiment is exemplary; in order to make those skilled in the art can better understand content of the present invention; should not be understood as limiting the scope of the invention; so long as the improvement of doing according to technical solution of the present invention all falls into protection scope of the present invention.

Claims (9)

1. the preparation method of a Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane, is characterized in that the method comprises the steps:
1) feedstock purification;
2) chemical treatment, contain three acid treatment and secondary alkaline purification;
3) physical treatment, contain ultrasonic grinding, and shredder grinds, three kinds of mechanical treatments of high-pressure homogeneous instrument;
4) preparation of fiber yarn nanofibrils film;
5) preparation of Mierocrystalline cellulose nanofibrils to epoxy resin composite material.
2. the preparation method of a kind of Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane as claimed in claim 1, it is characterized in that described feedstock purification step 1), the poplar wood powder is screened with 60 ~ 70 mesh sieve, then carry out Benzene-ethanol extraction (v/v=2:1) and remove grease and other wood powder impurity in wood powder, after extracting, use the absolute ethanol washing wood powder, remove toluene unnecessary in wood powder, wood powder after washing subsequently is positioned in culture dish, 24 ~ 48h ventilates in stink cupboard, treat the wood powder drying, get the chemical treatment of appropriate wood powder for the preparation of the Mierocrystalline cellulose nanofibrils.
3. the preparation method of a kind of Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane as claimed in claim 1, is characterized in that described chemical treatment step 2) in
acid treatment for the first time: get the 10g wood powder and be dissolved in 390ml distilled water, add the 3.9g Textone, be configured to concentration and be 1% sodium chlorite solution, simultaneously, add the acetic acid of 3 ~ 4ml to guarantee to become acidic conditions in wood powder solution, this moment, the pH value of solution was 4 ~ 5 after tested, this acid treatment process is in order to remove the xylogen composition in xylon, mixing solutions is 75 ℃ of heated sealed 1h in magnetic stirring apparatus, in mixing solutions, again add afterwards the 3.9g Textone, 3 ~ 4ml acetic acid, to guarantee that wood powder can react completely in enough Textones, this adds the treating processes of appropriate Textone and acetic acid to repeat 6 times every 1h, the color that can see wood powder in the acid treatment process becomes white by yellow,
Alkaline purification for the first time: for the first time after acid treatment, use distilled water to utilize vacuum filter filtration washing wood powder, the wood powder washing is extremely neutral, configure subsequently 400ml concentration and be 3% potassium hydroxide solution, be sealed in magnetic stirring apparatus and heat 90 ℃ of stirrings 2 hours, use afterwards the distilled water wash wood powder to neutral, this alkaline purification process is in order to remove the hemicellulose in xylon, the colloid in remaining starch and xylon;
Acid treatment for the second time: wood powder is added in the sodium chlorite solution of 1% concentration, add 3 ~ 4ml acetic acid to keep the acidic conditions of solution, 1h is stirred in 75 ℃ of sealings of heating in magnetic stirring apparatus afterwards, and this process repeats 3 times, and acid treatment for the second time is in order to remove the xylogen in xylon fully;
Alkaline purification for the second time: after acid treatment for the second time, it is neutral that wood powder is washed into, is added to 400ml concentration and is in 6% potassium hydroxide solution, heat 90 ℃ of stirring 2h, this process and the same meaning of acid treatment process for the second time are in order to remove more completely the hemicellulose in xylon;
Acid treatment for the third time namely, the salt acid treatment: after alkaline purification, wood powder is distilled water washing to neutral, adding 390ml concentration is 1% hydrochloric acid soln, 85 ℃ of stirring 2h of heating in magnetic stirring apparatus, the salt acid treatment is in order by xylon, to divide fine fibril, in order at physical mechanical, process the fibrillation process better, it is 0.5 ~ 1% solution that the xylon of finally finishing dealing with adds distilled water to be configured to mass concentration.
4. the preparation method of a kind of Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane as claimed in claim 1, is characterized in that in described step 3) physical treatment
Physics is ultrasonic: the xylon solution that configures is used to vegetable cell ultrasonic grinder ultrasonic 60min in ice-water bath, and temperature remains at 30 ℃ of following ultrasonication, finally obtains ultrasonic cellulose solution;
Shredder grinds: the xylon solution that configures is used to the stone mortar shredder, rotating speed is 1800rpm, regulating the distance between metate on shredder is 0.01 ~ 0.02mm, because be the wet grinding method, water has played and has made the grinding stone contact, but be unlikely the grinding stone effect broken because close contact generates heat, and grind 10 ~ 30 times, finally obtain the milled fibre cellulose solution;
High-pressure homogeneous instrument: after grinding, use high-pressure homogeneous instrument to carry out further physics fragmentation to resulting cellulose solution, the pressure of 1000 ~ 1500pa is set, homogeneous 30 ~ 60min, finally obtain uniform nanofiber cellulose solution, and this solution is light blue, transparent
After physical mechanical is opened fibre, the Mierocrystalline cellulose nanofibrils solution that obtains preparing: namely
1. ultrasonic 60min; 2. grind 30 times; 3. after grinding 30 times, follow ultrasonic 60min; 4. grind 30 times and follow afterwards homogeneous 60min.
5. the preparation method of a kind of Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane as claimed in claim 1, it is characterized in that described fiber yarn nanofibrils film preparation step 4), the Mierocrystalline cellulose nanofibrils solution that is 1 wt% by prepared concentration uses vacuum apparatus to filter, the filter membrane aperture of using is 0.2 μ m, diameter is 9cm, the diameter of Büchner funnel is 12cm, in Büchner funnel, first pad the filter paper of one deck 12cm diameter, again filter membrane fully is attached to the filter paper surface, use the wetting filter membrane of distilled water, and open vacuum pump and make filter membrane with Büchner funnel, fit fully, pour Mierocrystalline cellulose nanofibrils solution in Büchner funnel filtering coating this moment, after film forming, filter membrane is taken out, on the filter membrane surface with cellulose membrane, paste a filter membrane again, be clipped in the middle of two-layer facial tissue, the facial tissue that will accompany afterwards the nano-cellulose film is positioned in book, Air drying 9 ~ 10h, existing eighty per cant drying of nano-cellulose film this moment, subsequently the nano-cellulose film on filter membrane surface is slowly opened, for guaranteeing that the nano-cellulose film can not fit tightly the situation of taking off not open that causes with filter membrane in ensuing drying, the nano-cellulose film of opening is placed in to two filter membranes again, be clipped in facial tissue in the middle of two iron plates that are positioned in vacuum drying oven, 60 ℃ of high-pressure drying 24 ~ 48h, iron plate 2 ~ 3kg.
6. the preparation method of a kind of Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane as claimed in claim 1, is characterized in that described Mierocrystalline cellulose nanofibrils is to epoxy resin composite material preparation process 5), include
(1) preparation of pure epoxy resin film: extracting epoxy resin is in culture dish, add subsequently solidifying agent polyetheramine D230, the part by weight of epoxy resin and solidifying agent is 100/30, the mixture of epoxy resin and solidifying agent is hand operated mixing 10min at normal temperatures, make the reduced viscosity of epoxy resin, stirring fully reflects solidifying agent and epoxy resin, the epoxy resin that is stirred and curing agent mixture are placed in to 60 ℃ of baking ovens and heat 10min, further reduce the viscosity of epoxy resin composition, then be placed on the sheet glass with tetrafluoroethylene paper, in 60 ℃ of baking ovens, heat 40 ~ 60min, make epoxy resin and curing agent mixture present at this moment a kind of gel state, cover afterwards another piece and have equally the sheet glass of tetrafluoroethylene paper, in baking oven, be heating and curing after 24h and take out, matrix material is opened from tetrafluoroethylene paper, the thickness of this laminated film is 200 ~ 400 μ m, or
(2) with the standby Mierocrystalline cellulose nanofibrils of miscible legal system/epoxy resin laminated film: by Mierocrystalline cellulose nanofibrils solution after lyophilize, form dry nano-cellulose, get nano-cellulose, put into 50 ~ 60ml acetone, for Mierocrystalline cellulose is dispersed in acetone soln, just mixing solutions is placed in ultrasonic instrument, ultrasonic 30min under 30 ℃, at this moment, ultrasonic by in the dispersion of the nano-cellulose of freeze-drying and acetone soln, this mixing solutions is stirring at normal temperature 3 ~ 4h in magnetic stirrer, extracting epoxy resin adds in the acetone mixing solutions and stirs 4h subsequently, be placed in 60 ℃ of baking oven 3 ~ 5h, make acetone volatilize fully, add afterwards solidifying agent polyetheramine D230, the part by weight of epoxy resin and solidifying agent is 100/30, hand operated mixing mixture 5 ~ 10min, be positioned over the viscosity that reduces epoxy resin composition in baking oven, then mixture is poured on the sheet glass with tetrafluoroethylene paper, in 60 ℃ of baking ovens, heat 40 ~ 60min, make mixture present at this moment a kind of gel state, cover afterwards another piece and have equally the sheet glass of tetrafluoroethylene paper, in baking oven, be heating and curing after 24h and take out, matrix material is opened from tetrafluoroethylene paper, the thickness of this laminated film is 200 ~ 400 μ m, or
(3) with pickling process, prepare Mierocrystalline cellulose nanofibrils/epoxy resin laminated film: epoxy resin is added in the 60ml acetone soln, stirring at normal temperature 4h in magnetic stirrer, this moment, epoxy resin fully was dissolved in acetone soln, add afterwards the solidifying agent polyetheramine, the ratio of epoxy resin and polyetheramine is 100/30, and this epoxy systems continues stirring at normal temperature 1h in acetone; The Mierocrystalline cellulose nanofibrils for preparing is thin film dipped in the epoxy resin acetone soln, every after by this thin film suspending 50 ℃ of dryings in convection oven, take out afterwards.
7. the preparation method of a kind of Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane as claimed in claim 4, the ultrasonic power that it is characterized in that the ultrasonic employing of physics in described step 3) is 1000W ~ 1200W.
8. the preparation method of a kind of Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane as claimed in claim 6, is characterized in that the resin in described step 5) is epoxy resin E44, and solidifying agent is polyetheramine D230, and after epoxy resin cure, modulus is 1.1GPa.
9. the preparation method of a kind of Mierocrystalline cellulose nanofibrils/epoxy resin composite membrane as claimed in claim 1, is characterized in that described starting material, i.e. wood powder, cotton, printer paper, package paper.
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CN110475819A (en) * 2017-03-31 2019-11-19 太阳控股株式会社 Hardening resin composition, dry film, solidfied material and electronic component
CN108467570A (en) * 2018-04-20 2018-08-31 中国科学院理化技术研究所 A kind of nano-cellulose epoxy resin composite material and preparation method thereof
CN109251365A (en) * 2018-07-27 2019-01-22 华南理工大学 A kind of preparation and application of novel flexible organic solar batteries base material
CN109251365B (en) * 2018-07-27 2019-12-10 华南理工大学 preparation and application of flexible organic solar cell substrate material
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CN111136751A (en) * 2020-01-08 2020-05-12 东北林业大学 Wooden slip and preparation method and application thereof
CN111136751B (en) * 2020-01-08 2021-11-19 东北林业大学 Wooden slip and preparation method and application thereof
CN112252069A (en) * 2020-10-20 2021-01-22 北华大学 Preparation method of multifunctional super-hydrophobic formaldehyde-free artificial board
CN112480357A (en) * 2020-12-03 2021-03-12 衢州学院 Flame-retardant polyurethane nano-cellulose reinforced material and preparation method thereof
CN114351488A (en) * 2021-12-10 2022-04-15 西安理工大学 Composite-morphology nano-cellulose transparent film based on waste paper and preparation method thereof
CN114351488B (en) * 2021-12-10 2024-01-30 西安理工大学 Composite morphology nano cellulose transparent film based on waste paper and preparation method thereof
CN115635555A (en) * 2022-10-31 2023-01-24 中南林业科技大学 Preparation method of environment-friendly high-strength wood composite material
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