Hydrophobically modified nanocellulose crystal and a method for hydrophobic grafting modification of nanocellulose crystals
20180127517 ยท 2018-05-10
Inventors
- Jianhui Luo (Beijing, CN)
- Xinxiang ZHANG (Beijing, CN)
- Baoliang Peng (Beijing, CN)
- Pingmei Wang (Beijing, CN)
- Bin Ding (Beijing, CN)
- Lipeng He (Beijing, CN)
- Xiangfei Geng (Beijing, CN)
Cpc classification
C08B15/05
CHEMISTRY; METALLURGY
B01D69/02
PERFORMING OPERATIONS; TRANSPORTING
B82Y40/00
PERFORMING OPERATIONS; TRANSPORTING
C08K5/56
CHEMISTRY; METALLURGY
C08B15/00
CHEMISTRY; METALLURGY
C08L1/00
CHEMISTRY; METALLURGY
B01D61/14
PERFORMING OPERATIONS; TRANSPORTING
B82Y30/00
PERFORMING OPERATIONS; TRANSPORTING
C08K5/56
CHEMISTRY; METALLURGY
C08L1/00
CHEMISTRY; METALLURGY
International classification
C08B15/00
CHEMISTRY; METALLURGY
B82Y30/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
The present disclosure relates to a hydrophobically modified nanocellulose crystal and a method for hydrophobic grafting modification of nanocellulose crystals, comprising the steps: mixing the nanocellulose crystals with a saturated alkane, and stirring the resultant at room temperature or under a heating condition; while stirring, adding in sequence a polymethylhydrosiloxane containing a silicon-hydrogen bond and a catalyst; continuously stirring to complete the dehydrogenation reaction, then obtaining a mixed solution; and filtering the mixed solution by a polyvinylidene fluoride membrane, then drying it to complete the hydrophobic modification. A SiOC-chemical bonding is formed between the polymethylhydrosiloxane and the nanocellulose crystal in the method, enabling improvement of the hydrophobicity and water resistance of the nanocellulose crystal.
Claims
1. A method for hydrophobic grafting modification of nanocellulose crystals, comprising the steps of: mixing the nanocellulose crystals with a saturated alkane, and stirring the resultant at room temperature or under a heating condition; while stirring, adding in sequence a polymethylhydrosiloxane containing a silicon-hydrogen bond and a catalyst; continuously stirring to complete the dehydrogenation reaction, then obtaining a mixed solution; and filtering the mixed solution by a polyvinylidene fluoride membrane, then drying it to complete the hydrophobic modification.
2. The method according to claim 1, wherein the catalyst is a complex of chloroplatinic acid and isopropanol, a complex of chloroplatinic acid and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, a complex of chloroplatinic acid and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, or an organotin salt.
3. The method according to claim 1, wherein the saturated alkane is one of n-hexane, n-heptane, n-octane and n-nonane, or a combination thereof; the pore size of the polyvinylidene fluoride membrane is 0.45 microns; the rotate speed of the stirring is from 5000 rpm to 100000 rpm.
4. The method according to claim 1, wherein the pore size of the polyvinylidene fluoride membrane is 0.45 microns.
5. The method according to claim 1, wherein the rotate speed of the stirring is from 5000 rpm to 100000 rpm.
6. The method according to claim 1, wherein the polymethylhydrosiloxane containing a silicon-hydrogen bond includes one or both of a side hydrogen-polymethylhydrosiloxane with a silicon-hydrogen bond in the side-chain and a telohydrogen-polymethylhydrosiloxane with a silicon-hydrogen bond at the end; wherein the side hydrogen-polymethylhydrosiloxane has a molecular formula of: ##STR00003## wherein R, R.sub.1 and R.sub.2 are organic groups, more preferably one of methyl, ethyl, propyl, phenyl and trifluoropropyl; m0, n0, with m and n being an integer; and the telohydrogen-polymethylhydrosiloxane has a molecular formula of: ##STR00004## wherein R and R.sub.1 are organic groups, more preferably one of methyl, ethyl, propyl, phenyl and trifluoropropyl; m0, n0, with m and n being an integer.
7. The method according to claim 1, wherein the side hydrogen-polymethylhydrosiloxane has a hydrogen content of from 0.01% to 1.5%, preferably from 0.2% to 1.5%.
8. The method according to claim 1, wherein the telohydrogen-polymethylhydrosiloxane has a hydrogen content of from 0.01% to 1.0%, preferably from 0.2% to 1.0%.
9. The method according to claim 1, wherein the mass ratio of the nanocellulose crystal to the saturated alkane is from (1:10) to (1:100).
10. The method according to claim 1, wherein the mass ratio of the polymethylhydrosiloxane containing silicon-hydrogen bond to the nanocellulose crystal is from (0.1:1) to (2:1).
11. The method according to claim 10, wherein when a side hydrogen-polymethylhydrosiloxane having a hydrogen content of 0.2% is used, the mass ratio of the side hydrogen-polymethylhydrosiloxane to the nanocellulose crystal is from (0.6:1) to (2.0:1).
12. The method according to claim 10, wherein when a side hydrogen-polymethylhydrosiloxane having a hydrogen content of 1.0% is used, the mass ratio of the side hydrogen-polymethylhydrosiloxane to the nanocellulose crystal is from (0.2:1) to (2.0:1).
13. The method according to claim 10, wherein when a side hydrogen-polymethylhydrosiloxane having a hydrogen content of 1.5% is used, the mass ratio of the side hydrogen-polymethylhydrosiloxane to the nanocellulose crystal is from (0.1:1) to (2.0:1).
14. The method according to claim 1, wherein the complex of chloroplatinic acid and isopropanol is added in an amount of from 10 to 1000 ppm with respect to the amount of the polymethylhydrosiloxane; the complex of chloroplatinic acid and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane is added in an amount of from 10 to 1000 ppm with respect to the amount of the polymethylhydrosiloxane; the complex of chloroplatinic acid and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane is added in an amount of from 10 to 1000 ppm with respect to the amount of the polymethylhydrosiloxane.
15. The method according to claim 1, wherein the organotin salt is added in an amount of from 0.01% to 4% with respect to the amount of the polymethylhydrosiloxane.
16. The method according to claim 1, wherein the heating temperature is from 25 C. to 150 C.; the stirring time is from 0.5 min to 30 min; and the drying temperature is from 40 C. to 150 C.
17. A hydrophobically modified nanocellulose crystal prepared by the method according to claim 1.
18. The hydrophobically modified nanocellulose crystal according to claim 17, wherein the surface of hydrophobically modified nanocellulose crystal is grafted with hydroxyl groups.
Description
DESCRIPTION OF THE DRAWINGS
[0025]
[0026]
[0027]
[0028]
[0029]
[0030]
[0031]
DETAILED DESCRIPTION OF THE DISCLOSURE
[0032] The technical solutions of the present disclosure are now described in detail in order to provide more explicit understanding of the technical features, objects and advantages of the present disclosure, which are not to be interpreted as limitation of the implementable scope of the disclosure.
COMPARATIVE EXAMPLE
[0033] The Comparative Example provides a method for hydrophobic grafting modification of nanocellulose crystals, comprising the steps of:
[0034] mixing 1.0 g of nanocellulose crystals and 50.0 g of n-hexane without adding any catalyst; disperse the nanocellulose crystals forcedly in the saturated alkane by high-speed shearing with a stirrer for 1 min at room temperature; filtering the samples through an polyvinylidene fluoride membrane with a pore size of 0.45 microns and placing the resultant in a vacuum oven and drying it at 45 C.
[0035] The structure of the non-hydrophobically modified nanocellulose is shown in
[0036] The non-hydrophobically modified nanocellulose crystals contained a large amount of hydroxyl groups on their surfaces.
[0037] The non-hydrophobically modified nanocellulose crystals were measured in a contact angle test and water resistance test (test apparatus: Krss DSA100 dynamic water contact angle measuring instrument).
[0038] The non-hydrophobically modified nanocellulose crystals were evenly spread on a glass slide to measure their dynamic contact angle with water, and the measured droplet volume was 0.5 microliters. The results showed that the non-hydrophobically modified nanocellulose crystals were excellent in hydrophilicity. When the droplets came into contact with the surface of the nanocellulose crystals, the droplets were rapidly absorbed and thus the contact angle was 0 degree (as shown in
[0039] The non-hydrophobically modified nanocellulose crystals were added to a serum bottle filled with distilled water, shaken and the sample glass bottle was inverted. The results showed that the non-hydrophobically modified nanocellulose crystals were rapidly dispersed in the distilled water, indicating poor water resistance.
Example 1
[0040] This Example provides a method for hydrophobic grafting modification of nanocellulose crystals, comprising the steps of:
[0041] Mixing 1.0 g of nanocellulose crystals and 20.0 g of n-hexane, dispersing the nanocellulose crystals forcedly in the saturated alkane by high-speed shearing at room temperature with a stirrer for 1 min; while high-speed stirring, adding in sequence 0.6 g of a side hydrogen-polymethylhydrosiloxane having a hydrogen content of 0.2% (i.e., the side hydrogen-polymethylhydrosiloxane is added in an amount of 60% with respect to the nanocellulose crystal) and 20 ppm of the complex of chloroplatinic acid and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (as a catalyst, in terms of Pt); continuously shearing for 1 min, to complete the modification; filtering the samples through an polyvinylidene fluoride membrane with a pore size of 0.45 microns, placing the resultant in a vacuum oven and drying it at 45 C.
[0042] The reaction equation of the nanocellulose crystals modified with the side hydrogen-polymethylhydrosiloxane having a hydrogen content of 0.2% is shown in
[0043] The equation in
[0044] The nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 0.2%) prepared in this Example were measured in the contact angle test and water resistance test (test apparatus: Krss DSA100 dynamic water contact angle measuring instrument).
[0045] The nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 0.2%) prepared in this Example were evenly spread on a glass slide to measure their dynamic contact angle with water, and the measured droplet volume was 0.5 microliters. The results showed that the nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 0.2%) prepared in this Example were good in hydrophilicity. When the droplets came into contact with the surface of the nanocellulose crystals, the droplets were not absorbed, but formed a droplet with a contact angle of up to 118 degrees on the surface thereof (as shown in
[0046] The nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 0.2%) were added to a serum bottle filled with distilled water, shaken and the sample glass bottle was inverted. After inversion, the nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 0.2%) were completely floating on the surface of distilled water, indicating excellent water resistance, totally unwettable by water.
[0047] The FTIR spectra (as shown in
Example 2
[0048] This Example provides a method for hydrophobic grafting modification of nanocellulose crystals, comprising the steps of:
[0049] Mixing 1.0 g of nanocellulose crystals and 50.0 g of n-hexane, dispersing the nanocellulose crystals forcedly in the saturated alkane by high-speed shearing at room temperature with a stirrer for 1 min; while high-speed stirring, adding in sequence 0.1 g of a side hydrogen-polymethylhydrosiloxane having a hydrogen content of 1.0% (i.e., the side hydrogen-polymethylhydrosiloxane is added in an amount of 10% with respect to the nanocellulose crystal) and 20 ppm of the complex of chloroplatinic acid and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (as a catalyst, in terms of Pt); continuously shearing for 1 min, to complete the modification; filtering the samples through an polyvinylidene fluoride membrane with a pore size of 0.45 microns, placing the resultant in a vacuum oven and drying it at 45 C.
[0050] The reaction equation of the nanocellulose crystals modified with the side hydrogen-polymethylhydrosiloxane having a hydrogen content of 1.0% is shown in
[0051] The equation in
[0052] The nanocellulose crystals modified with 10% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.0%) prepared in this Example were measured in the contact angle test and water resistance test (test apparatus: Krss DSA100 dynamic water contact angle measuring instrument).
[0053] The nanocellulose crystals modified with 10% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.0%) prepared in this Example were evenly spread on a glass slide to measure their dynamic contact angle with water, and the measured droplet volume was 0.5 microliters. The results showed that the nanocellulose crystals modified with 10% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.0%) prepared in this Example were good in hydrophilicity. When the droplets came into contact with the surface of the nanocellulose crystals, the droplets were not absorbed, but formed a droplet with a contact angle of up to 110 degrees on the surface thereof (as shown in
[0054] The nanocellulose crystals modified with 10% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.0%) were added to a serum bottle filled with distilled water, shaken and the sample glass bottle was inverted. After inversion, the nanocellulose crystals modified with 10% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.0%) were completely floating on the surface of distilled water, indicating excellent water resistance, totally unwettable by water.
Example 3
[0055] This Example provides a method for hydrophobic grafting modification of nanocellulose crystals, comprising the steps of:
[0056] Mixing 1.0 g of nanocellulose crystals and 100.0 g of n-hexane, dispersing the nanocellulose crystals forcedly in the saturated alkane by high-speed shearing at room temperature with a stirrer for 1 min; while high-speed stirring, adding in sequence 0.6 g of side hydrogen-polymethylhydrosiloxane having a hydrogen content of 1.0% (i.e., the side hydrogen-polymethylhydrosiloxane is added in an amount of 60% with respect to the nanocellulose crystal) and 20 ppm of the complex of chloroplatinic acid and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (as a catalyst, in terms of Pt); continuously shearing for 1 min, to complete the modification; filtering the samples through an polyvinylidene fluoride membrane with a pore size of 0.45 microns, placing the resultant in a vacuum oven and drying it at 45 C.
[0057] The nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.0%) prepared in this Example were measured in the contact angle test and water resistance test (test apparatus: Krss DSA100 dynamic water contact angle measuring instrument).
[0058] The nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.0%) prepared in this Example were evenly spread on a glass slide to measure their dynamic contact angle with water, and the measured droplet volume was 0.5 microliters. The results showed that the nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.0%) prepared in this Example were excellent in hydrophilicity. When the droplets came into contact with the surface of the nanocellulose crystals, the droplets rolled away rapidly from its surface, which is superhydrophobic (as shown in
[0059] The nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.0%) were added to a serum bottle filled with distilled water, shaken and the sample glass bottle was inverted. After inversion, the nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.0%) were completely floating on the surface of distilled water, indicating excellent water resistance, totally unwettable by water.
[0060] The FTIR spectra (as shown in
Example 4
[0061] This Example provides a method for hydrophobic grafting modification of nanocellulose crystals, comprising the steps of:
[0062] Mixing 1.0 g of nanocellulose crystals and 50.0 g of n-hexane, dispersing the nanocellulose crystals forcedly in the saturated alkane by high-speed shearing at room temperature with a stirrer for 1 min; while high-speed stirring, adding in sequence 0.6 g of a side hydrogen-polymethylhydrosiloxane having a hydrogen content of 1.5% (i.e., the side hydrogen-polymethylhydrosiloxane is added in an amount of 60% with respect to the nanocellulose crystal) and 20 ppm of the complex of chloroplatinic acid and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (as a catalyst, in terms of Pt); continuously shearing for 1 min, to complete the modification; filtering the samples through an polyvinylidene fluoride membrane with a pore size of 0.45 microns, placing the resultant in a vacuum oven and drying it at 45 C.
[0063] The reaction equation of the nanocellulose crystals modified with the side hydrogen-polymethylhydrosiloxane having a hydrogen content of 1.5% is shown in
[0064] The equation in
[0065] The nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.5%) prepared in this Example were measured in the contact angle test and water resistance test (test apparatus: Krss DSA100 dynamic water contact angle measuring instrument).
[0066] The nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.5%) prepared in this Example were evenly spread on a glass slide to measure their dynamic contact angle with water, and the measured droplet volume was 0.5 microliters. The results showed that the nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.5%) prepared in this Example were good in hydrophilicity. When the droplets came into contact with the surface of the nanocellulose crystals, the droplets were not absorbed, but formed a droplet with a contact angle of up to 100 degrees on the surface thereof (as shown in
[0067] The nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.5%) were added to a serum bottle filled with distilled water, shaken and the sample glass bottle was inverted. After inversion, the nanocellulose crystals modified with 60% of side hydrogen-polymethylhydrosiloxane (a hydrogen content of 1.5%) were completely floating on the surface of distilled water, indicating excellent water resistance, totally unwettable by water.
[0068] The FTIR spectra (as shown in
Example 5
[0069] This Example provides a method for hydrophobic grafting modification of nanocellulose crystals, comprising the steps of:
[0070] Mixing 1.0 g of nanocellulose crystals and 50.0 g of n-hexane, dispersing the nanocellulose crystals forcedly in the saturated alkane by high-speed shearing at room temperature with a stirrer for 1 min; while high-speed stirring, adding in sequence 0.6 g of a telohydrogen-polymethylhydrosiloxane having a hydrogen content of 0.5% (i.e., the telohydrogen-polymethylhydrosiloxane is added in an amount of 60% with respect to the nanocellulose crystal) and 20 ppm of the complex of chloroplatinic acid and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (as a catalyst, in terms of Pt); continuously shearing for 1 min, to complete the modification; filtering the samples through an polyvinylidene fluoride membrane with a pore size of 0.45 microns, placing the resultant in a vacuum oven and drying it at 45 C.
[0071] The reaction equation of the nanocellulose crystals modified with the telohydrogen-polymethylhydrosiloxane having a hydrogen content of 0.5% is shown in
[0072] The equation in
[0073] The nanocellulose crystals modified with 60% of telohydrogen-polymethylhydrosiloxane (a hydrogen content of 0.5%) prepared in this Example were measured in the contact angle test and water resistance test (test apparatus: Krss DSA100 dynamic water contact angle measuring instrument).
[0074] The nanocellulose crystals modified with 60% of telohydrogen-polymethylhydrosiloxane (a hydrogen content of 0.5%) prepared in this Example were evenly spread on a glass slide to measure their dynamic contact angle with water, and the measured droplet volume was 0.5 microliters. The results showed that the nanocellulose crystals modified with 60% of telohydrogen-polymethylhydrosiloxane (a hydrogen content of 0.5%) prepared in this Example were in good hydrophilicity. When the droplets came into contact with the surface of the nanocellulose crystals, the droplets were not absorbed, but formed a droplet with a contact angle of up to 115 degrees on the surface thereof (as shown in
[0075] The nanocellulose crystals modified with 60% of telohydrogen-polymethylhydrosiloxane (a hydrogen content of 0.5%) were added to a serum bottle filled with distilled water, shaken and the sample glass bottle was inverted. After inversion, the nanocellulose crystals modified with 60% of telohydrogen-polymethylhydrosiloxane (a hydrogen content of 0.5%) were completely floating on the surface of distilled water, indicating excellent water resistance, totally unwettable by water.