CN106749378B

CN106749378B - A kind of dynamics enhancement type polysilsesquioxane aerogel and preparation method thereof

Info

Publication number: CN106749378B
Application number: CN201611238801.7A
Authority: CN
Inventors: 云山; 郭探; 张加栋; 朱秀芳; 高晓燕; 李彦兴; 徐海清; 洪坤; 陈静
Original assignee: Huaiyin Institute of Technology
Current assignee: Shandong Huacui Energy Conservation Technology Co ltd
Priority date: 2016-12-28
Filing date: 2016-12-28
Publication date: 2019-05-24
Anticipated expiration: 2036-12-28
Also published as: CN106749378A

Abstract

The invention discloses a mechanically enhanced polysilsesquioxane aerogel, which is characterized in that the copolymer molecule contains at least one urea group capable of forming a hydrogen bond. Trialkoxysilane reacts with isocyanate group-containing organic monomers or oligomers, and then mixes with strong polar organic solvents. Using acid-base two-step catalysis, wet gels are prepared by sol-gel, and then dried to obtain corresponding Aerogel. The pore size distribution is 2~500nm, the BET specific surface area is 100~1000 m ² ·g ^‑1 , the density is 0.01~0.85 g·cm ^‑3 , the porosity is 57.5~99.5%, and the thermal conductivity is 0.01~0.10 W·m ^‑1 ·k ^‑1 , the compressive modulus is 5~300 MPa, the flexural modulus is 1~50 MPa, and it can withstand high temperatures above 300 ℃ in an air atmosphere. The polysilsesquioxane aerogel prepared by the invention has good blockability, high porosity, high strength, low thermal conductivity, good thermal stability, simple preparation process and short cycle. The prepared urea group-containing hydrogen bond polysilsesquioxane aerogel can be applied to the fields of building energy saving, petrochemical industry, sewage treatment and the like.

Description

A kind of dynamics enhancement type polysilsesquioxane aerogel and preparation method thereof

Technical field

The invention belongs to chemical materials preparation field more particularly to dynamics enhancement type polysilsesquioxane aerogel materials Preparation.

Background technique

Aerosil is a kind of new material with three-D nano-porous structure, have low-density (0.003 ~ 0.8g·cm^-3), high porosity (80 ~ 99.8%), high-specific surface area (200 ~ 1000m²·g^-1), lower thermal conductivity (~ 0.02Wm^- ¹K^-1) etc. properties, have in application fields such as aerospace, chemical industry, energy saving building, military affairs, communication, electronics, metallurgy very wide Prospect.However aerosil is not used widely, this is primarily due to aerosil by secondary ball Shape particle is interconnected to form three-dimensional net structure in the form of chain pearl, and this connection type connects adjacent offspring The area at position is smaller, is easily broken off under external force broken, and structure collapses lead to poor mechanical property.

United States Patent (USP) US7078359 B2, US8214980 B2 and Chinese patent CN1803602A, CN101318659A, CN101671030A, CN101973752A improve the mechanical strength of aeroge using fiber as reinforced phase.Although compound gas The mechanical strength of gel increases, but fibre diameter is more much bigger than aeroge aperture, and the network structure resulted in is uneven Even, composite material haves the defects that certain.In addition, the compatibility of reinforced phase fibrous material and aeroge matrix also will affect material Comprehensive performance.U.S. Meador et al. uses enhancing by polymer SiO₂Aeroge, using polymer in SiO₂Particle surface is formed Clad improves the mechanical strength of aeroge by increasing the width of neck between particle and particle, research shows that polymer Introduce and the elasticity modulus of aeroge can be improved into two orders of magnitude, reinforcing effect is significant.They are first in SiO₂Gel table The upper special functional group's such as amino of face modification, by the solvent that the gel of modification is immersed in certain organic monomers after exchange of solvent In, then cause polymerization and supercritical drying obtains the SiO of enhancing by polymer₂Aeroge, as polyureas enhances SiO₂Aeroge, ring Oxygen enhances SiO₂Aeroge, polystyrene enhance SiO₂Aeroge etc..But this method leads to the aeroge density big (> 0.4 of preparation g·cm^-3), therefore solid phase conduction of heat is stronger, the higher (> 0.04Wm of thermal conductivity^-1·k^-1).

In the case where improving the mechanical strength of aeroge without increasing considerably aeroge density, Boday et al. is adopted Polybutylcyanoacrylate composite S iO is prepared with the method for chemical vapor deposition₂Aeroge.They are existed using sol-gel method SiO₂Gel surface modifies amino, and then supercritical drying prepares amino-containing SiO₂Aeroge passes through the side of chemical vapor deposition Cyanoacrylate is diffused into aeroge by method in gaseous form, obtains poly- alpha-cyanoacrylate by anionic polymerisation The SiO of ester crosslinking₂The composite aerogel of composite aerogel, preparation has low density (0.095-0.230 gcm^-3), than pure Amido modified SiO₂Aeroge intensity improves 31 times.In conclusion the key for improving aeroge mechanical strength is to enhance Connectivity and interaction between offspring, current method are first by SiO₂Gel surface is modified, then passes through leaching Bubble carries out cross-linking reaction after diffusion balance in organic monomer solution or is crosslinked by the method for vapor deposition, obtains power Learn the crosslinked polymer SiO of enhancing₂Aeroge.But the above method needs the mistake of modified gel, exchange of solvent and monomer diffusion Journey, the period is long, preparation efficiency is low.

Therefore, there is still a need for a kind of simple process, high-efficient production method prepare the airsetting glue material of excellent combination property Material, pushes the scale application of aeroge.

Summary of the invention

It is poly- the purpose of the invention is to overcome the deficiencies of the prior art and provide a kind of dynamics enhancement type of hydrogen bond containing urea groups Silsesquioxane aeroge.

It is a further object of the present invention to provide a kind of preparations of dynamics enhancement type polysilsesquioxane aerogel of the invention Method.

The present invention is achieved by the following technical solutions:

A kind of dynamics enhancement type polysilsesquioxane aerogel, the general structure of the polysilsesquioxane aerogel are, wherein R beOr, n 1,2 or 3.

Further improvement of the present invention scheme are as follows:

The method of the dynamics enhancement type polysilsesquioxane aerogel, comprises the following specific steps that:

Step 1: organic monomer or oligomer containing isocyanate group are pressed by the trialkoxy silane containing amido functional group Amino is that 1:1 is mixed with isocyanate group molar ratio, and the trialkoxy silane containing ureido groups is made in 0.5 ~ 4h of reaction；

Step 2: the above-mentioned trialkoxy silane containing ureido groups is mixed in proportion with polar organic solvent, it is added After acidic catalyst stirring, adds basic catalyst and carry out gelation, obtain polysilsesquioxane wet gel, gelling temperature It is 0 ~ 90 DEG C, gelation time is 0.1 ~ 20h, the trialkoxy silane containing ureido groups, organic solvent, acidic catalyst Agent, basic catalyst molar ratio be 1: 20 ~ 200: 0.001 ~ 0.05: 0.005 ~ 0.5, preferably 1: 80 ~ 180: 0.002 ~ 0.01:0.008 ~ 0.2.

Step 3: the gel that step 2 is obtained uses 18 ~ 48h of acetone soak at 40 ~ 60 DEG C, then it is dried, obtains To polysilsesquioxane aerogel.

Trialkoxy silane described in step 1 containing amido functional group is 3- aminopropyl triethoxysilane, 3- aminopropyl Trimethoxy silane, diethylenetriamine base propyl trimethoxy silicane, diethylenetriamine base propyl-triethoxysilicane, N- (β- Aminoethyl) one of-γ-aminopropyltrimethoxysilane or N- (β-aminoethyl)-gamma-aminopropyl-triethoxy-silane or two Kind or more mixing.

Organic monomer or oligomer described in step 1 containing isocyanate group are monoisocyanates, diisocyanate, three One of isocyanates or poly isocyanate or two or more mixing；

The monoisocyanates is ethyl isocyanate, isopropyl isocyanate, 2- naphthyl isocyanate, 4- bromobenzene isocyanic acid Ester, isocyanic acid benzenesulfonyl, to toluene diisocyanate, toluene diisocyanate, m-chloro phenylisocyanate, tert-butyl isocyanic acid Ester, adjacent chlorobenzene isocyanates, adjacent toluene diisocyanate, cyclohexyl isocyanate, octadecylisocyanate or dodecyl are different Cyanate；

The diisocyanate is hexamethylene diisocyanate, paraphenylene diisocyanate, 4,4'- di-2-ethylhexylphosphine oxide (isocyanide Acid phenenyl ester), 4,4'- diisocyanate base -3,3'- dimethyl diphenyl, isophorone diisocyanate, the own diisocyanate of trimethyl Ester, 2,4- toluene di-isocyanate(TDI), 2,6- toluene di-isocyanate(TDI)；

The triisocyanate is triphenylmethane triisocyanate, L-lysine triisocyanate.

Polar organic solvent described in step 2 is formamide, acetamide, dimethyl sulfoxide, tetrahydrofuran, N- methyl pyrrole The mixing of one or more of pyrrolidone, acetonitrile or propionitrile.

Acidic catalyst described in step 2 is in hydrochloric acid, sulfuric acid, phosphoric acid, hydrofluoric acid, formic acid, acetic acid, propionic acid or oxalic acid One or two kinds of above mixing, the concentration of the acidic catalyst is 0.001 ~ 1 molL^-1, preferably 0.01 ~ 0.2mol·L^-1。

Basic catalyst described in step 2 is one of hexamethylenetetramine, urea, ammonium hydroxide or two or more mixed It closes, the concentration of the basic catalyst is 0.1 ~ 5 molL^-1, preferably 0.1 ~ 2molL^-1。

The gelling temperature is 40 ~ 70 DEG C, and gel time is 10 ~ 20 h.

Further improvement project of the invention are as follows:

Above-mentioned dynamics enhancement type polysilsesquioxane aerogel answering in fields such as building, petrochemical industry or sewage treatments With.

The invention has the benefit that

1. aerogel material provided by the invention uses the organosilan containing ureido groups as presoma, urea is utilized The hydrogen bond formed between base group improves the mechanical strength of aeroge, modified with the subsequent compound place of polymer without gel surface Reason.

2. increasing the active force between strand there are hydrogen bond in aeroge molecular structure provided by the invention, improve Aeroge aerial thermostabilization.

3. aeroge of the invention, pore-size distribution is 2 ~ 500nm, 100 ~ 1000 m of BET specific surface area²·g^-1, density For 0.01 ~ 0.85 gcm^-3, porosity is 57.5 ~ 99.5%, and thermal conductivity is 0.01 ~ 0.10 Wm^-1·k^-1, compression modulus is 5 ~ 300 MPa, bending modulus are 1 ~ 50 MPa, and 300 DEG C or more high temperature are resistant in air atmosphere.

Detailed description of the invention

Fig. 1 is the graph of pore diameter distribution of the polysilsesquioxane aerogel of the hydrogen bond containing urea groups prepared by embodiment 1.

Fig. 2 is the scanning electron microscope (SEM) photograph of the polysilsesquioxane aerogel of the hydrogen bond containing urea groups prepared by embodiment 1.

Fig. 3 is the graph of pore diameter distribution of the polysilsesquioxane aerogel of the hydrogen bond containing urea groups prepared by embodiment 3.

Fig. 4 is the scanning electron microscope (SEM) photograph of the polysilsesquioxane aerogel of the hydrogen bond containing urea groups prepared by embodiment 3.

It the graph of pore diameter distribution of the polysilsesquioxane aerogel of the resulting hydrogen bond containing urea groups of the embodiment of the present invention 2,4,5 and sweeps It retouches electron microscope as space is limited, is not included in attached drawing.

Specific embodiment

Embodiment 1

In molar ratio it is 2:1,3- aminopropyl triethoxysilane and hexamethylene diisocyanate is mixed, stirred at room temperature It mixes 4 h of reaction and obtains the siloxane precursors containing urea groups；It is added after siloxane precursors containing urea groups are mixed with formamide 0.1mol·L^-1Hydrochloric acid stir 2 h；Add 1molL^-1Ammonium hydroxide stir 5 min, standing obtain gel, wherein contain urea The siloxane precursors of base, formamide, hydrochloric acid, ammonium hydroxide molar ratio be 1:80:0.002:0.008.

Gel obtained above is used into 24 ~ 48h of acetone soak at 40 ~ 60 DEG C, then under 60 ~ 80 DEG C of atmospheric pressure environment Drying for 24 hours, obtains polysilsesquioxane aerogel containing urea groups.

The density of above-mentioned polysilsesquioxane aerogel is 0.21 gcm^-3, porosity 89.5%, using nitrogen adsorption instrument Measuring BET specific surface area is 300m²·g^-1, pore-size distribution is 5 ~ 250nm；Compression modulus is measured using electronic universal tester, 50MPa, bending modulus 7MPa；Thermal conductivity 0.032Wm is measured using Adsorbent By Using Transient Plane Source Technique^-1·k^-1, surveyed using thermogravimetry It obtains aeroge and is resistant to 305 in air atmosphere^oC。

Embodiment 2

It is in molar ratio 2:1, by 3- aminopropyl triethoxysilane and 4,4'- di-2-ethylhexylphosphine oxide (phenyl isocyanate) is mixed, It reacts at room temperature 2 h and obtains the siloxane precursors containing urea groups；It is added after siloxane precursors containing urea groups are mixed with acetamide 0.05mol·L^-1Hydrochloric acid stir 2 h；Add 1molL^-1Ammonium hydroxide, stir 5 min, standing obtain gel, wherein containing The siloxane precursors of urea groups, acetamide, hydrochloric acid, ammonium hydroxide molar ratio be 1:100:0.005:0.01.

Gel obtained above is used into 20 h of acetone soak at 40 DEG C, it is then dry under 50 ~ 100 DEG C of atmospheric pressure environment 48h obtains polysilsesquioxane aerogel containing urea groups.

The density of above-mentioned polysilsesquioxane aerogel is 0.18 gcm^-3, porosity 91.0%, using nitrogen adsorption instrument Measuring BET specific surface area is 240m²·g^-1, pore-size distribution is 10 ~ 220nm；Compression modulus is measured using electronic universal tester 37 MPa, bending modulus are 5 MPa；0.03 Wm of thermal conductivity is measured using Adsorbent By Using Transient Plane Source Technique^-1·k^-1, utilize thermogravimetry It measures aeroge and is resistant to 340 in air atmosphere^oC。

Embodiment 3

It is in molar ratio 2:1, by 3- aminopropyl trimethoxysilane and 4,4'- di-2-ethylhexylphosphine oxide (phenyl isocyanate) is mixed, It reacts at room temperature 2 h and obtains the siloxane precursors containing urea groups；It is added after siloxane precursors containing urea groups are mixed with acetamide 0.05mol·L^-1Hydrochloric acid stir 2 h；Add 1molL^-1Ammonium hydroxide, stir 5 min, standing obtain gel, wherein containing The siloxane precursors of urea groups, acetamide, hydrochloric acid, ammonium hydroxide molar ratio be 1:120:0.007:0.05.

Gel obtained above is used into 20 ~ 36 h of acetone soak at 30 ~ 50 DEG C, then uses supercritical CO₂It is dry, it obtains To polysilsesquioxane aerogel containing urea groups.The density of above-mentioned polysilsesquioxane aerogel is 0.11 gcm^-3, porosity 94.5%, use nitrogen adsorption instrument to measure BET specific surface area as 545 m²·g^-1, pore-size distribution is 2 ~ 100nm；Using electronics ten thousand Energy testing machine measures 10.5 MPa of compression modulus, and bending modulus is 2.1 MPa, measures thermal conductivity using Adsorbent By Using Transient Plane Source Technique 0.022W·m^-1·k^-1, aeroge is measured using thermogravimetry, and 340 are resistant in air atmosphere^oC。

Embodiment 4

It is in molar ratio 2:1, by 3- aminopropyl trimethoxysilane and 4,4'- di-2-ethylhexylphosphine oxide (phenyl isocyanate) is mixed, It reacts at room temperature 2 h and obtains the siloxane precursors containing urea groups；Add after siloxane precursors containing urea groups are mixed with acetamide 0.05mol·L^-1Hydrochloric acid stir 2 h；Add 1molL^-1Ammonium hydroxide, stir 5 min, standing obtain gel, wherein containing The siloxane precursors of urea groups, acetamide, hydrochloric acid, ammonium hydroxide molar ratio be 1:140:0.01:0.08.

By gel obtained above at 40 ~ 60 DEG C use 18 ~ 24 h of acetone soak, then under vacuum conditions dry 24 ~ 48h obtains polysilsesquioxane aerogel containing urea groups.The density of above-mentioned polysilsesquioxane aerogel is 0.08 gcm^-3, hole Gap rate 95.9% uses nitrogen adsorption instrument to measure BET specific surface area as 140m²·g^-1, pore-size distribution is 2 ~ 200nm；Using electronics Universal testing machine measures 8.5 MPa of compression modulus, and bending modulus is 1.2 MPa, measures thermal conductivity using Adsorbent By Using Transient Plane Source Technique 0.021 Wm-1k-1 measures aeroge using thermogravimetry and is resistant to 340 in air atmosphere^oC。

Embodiment 5

It is in molar ratio 2:1, by 3- aminopropyl trimethoxysilane and 4,4'- di-2-ethylhexylphosphine oxide (phenyl isocyanate) is mixed, It reacts at room temperature 1 h and obtains the siloxane precursors containing urea groups；After being mixed containing the siloxane precursors containing urea groups with tetrahydrofuran 0.2molL is added^-1Hydrochloric acid stir 3 h；Add 2molL^-1Ammonium hydroxide stir 5 min, standing obtain gel, wherein The molar ratio of siloxane precursors, tetrahydrofuran, hydrochloric acid, ammonium hydroxide containing urea groups is 1:180:0.01:0.2.

Gel obtained above is used into 24 ~ 48 h of acetone soak at 30 ~ 60 DEG C, then in 70 ~ 100 DEG C of atmospheric pressure environment Lower drying for 24 hours, obtains polysilsesquioxane aerogel containing urea groups.The density of above-mentioned polysilsesquioxane aerogel is 0.05 g cm^-3, porosity 97.5% uses nitrogen adsorption instrument to measure BET specific surface area as 605m²·g^-1, pore-size distribution is 5 ~ 300nm, is adopted 5 MPa of compression modulus is measured with electronic universal tester, bending modulus is 1 MPa, using Adsorbent By Using Transient Plane Source Technique thermal conductivity 0.017W·m^-1·k^-1, aeroge is measured using thermogravimetry, and 340 are resistant in air atmosphere^oC。

Claims

1. a method for preparing mechanically enhanced polysilsesquioxane aerogel, is characterized in that, is prepared by following concrete steps:

Step 1. Under solvent-free conditions, the trialkoxysilane containing amino functional group and 4,4'-methylenebis(phenyl isocyanate) are mixed according to the molar ratio of amino group and isocyanate group as 1:1, and the reaction is carried out. 0.5~4h to prepare trialkoxysilane containing urea group;

Step 2: Mix the above-mentioned trialkoxysilane containing urea group with polar organic solvent in proportion, add an acidic catalyst to stir, and then add an alkaline catalyst to gel to obtain polysilsesquioxane wet coagulation. glue, the gelling temperature is 0～90 ℃, the gelling time is 0.1～20h, and the mol ratio of the trialkoxysilane containing urea group, organic solvent, acidic catalyst, basic catalyst is 1: 20~200 : 0.001~0.05 : 0.005~0.5;

Step 3: soak the gel obtained in step 2 with acetone at 40-60° C. for 18-48 hours, and then dry to obtain polysilsesquioxane aerogel;

The polar organic solvent is one or a mixture of two or more of formamide, acetamide, dimethyl sulfoxide, tetrahydrofuran, N-methylpyrrolidone, acetonitrile or propionitrile.

2. the preparation method of a kind of mechanically enhanced polysilsesquioxane aerogel according to claim 1 is characterized in that: the trialkoxysilane containing amino functional group described in step 1 is 3-aminopropyl triethoxysilane, 3-aminopropyltrimethoxysilane, diethylenetriaminopropyltrimethoxysilane, diethylenetriaminopropyltriethoxysilane, N-(β-aminoethyl )-γ-aminopropyltrimethoxysilane or N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, or a mixture of two or more.

3. the preparation method of a kind of mechanically enhanced polysilsesquioxane aerogel according to claim 1, is characterized in that: the acid catalyst described in step 2 is hydrochloric acid, sulfuric acid, phosphoric acid, hydrofluoric acid, formic acid One or more of acetic acid, propionic acid or oxalic acid are mixed, and the concentration of the acidic catalyst is 0.001~1 mol·L ^-1 .

4 . The method for preparing a mechanically enhanced polysilsesquioxane aerogel according to claim 1 or 3 , wherein the concentration of the acidic catalyst is 0.01-0.2 mol·L ⁻¹ . 5 .

5. the preparation method of a kind of mechanically enhanced polysilsesquioxane aerogel according to claim 1, is characterized in that: the basic catalyst described in step 2 is hexamethylenetetramine, urea, ammoniacal liquor One or two or more of them are mixed, and the concentration of the basic catalyst is 0.1-5 mol·L ^-1 .

6 . The method for preparing a mechanically enhanced polysilsesquioxane aerogel according to claim 1 or 5 , wherein the concentration of the basic catalyst is 0.1 to 2 mol·L ⁻¹ . 7 .

7 . The method for preparing a mechanically enhanced polysilsesquioxane aerogel according to claim 1 , wherein: the trialkoxysilane containing urea group described in step 2, an organic solvent, The molar ratio of the acidic catalyst and the basic catalyst is 1:80~180:0.002~0.01:0.008~0.2.

8. The preparation method of a mechanically enhanced polysilsesquioxane aerogel according to claim 1, wherein the gelation temperature is 40-70°C, and the gelation time is 10-20 h .