Method for preparing super thermal isolation polymer materials from polymer nanometer hollow capsules

A technology for the preparation of polymer materials and capsules, which is applied in the preparation of microcapsule preparations and microspheres, can solve the problems of inability to obtain nanoporous foam materials and porous materials, and achieve simple preparation processes, good mechanical strength, and high intensity effect

Active Publication Date: 2012-06-20
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The foaming process of the traditional foaming method is an uncontrollable process. The bubbles of the obtained material range from tens of microns to hundreds of microns, and nanoporous foam materials cannot be obtained.
However, the high internal phase emulsion method cannot obtain nanoscale porous materials due to the limitation of surface tension.

Method used

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  • Method for preparing super thermal isolation polymer materials from polymer nanometer hollow capsules
  • Method for preparing super thermal isolation polymer materials from polymer nanometer hollow capsules
  • Method for preparing super thermal isolation polymer materials from polymer nanometer hollow capsules

Examples

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preparation example Construction

[0056] The preparation method step of described melamine formaldehyde resin is as follows:

[0057] 1) Weighing 40-70 parts by weight of formaldehyde, adding triethylamine or sodium hydroxide solution dropwise to adjust the pH to 7.8-8.5. Then add 10-30 parts by weight of melamine to formaldehyde, and react at 60-85° C. for 15-40 minutes.

[0058] 2) Add 15-40 parts by weight of methanol to the reactant, adjust the pH to 4.0-6.5 with hydrochloric acid, react at 40-60° C. for 30-60 minutes, and end the reaction to obtain melamine formaldehyde resin for use. The mass percentage content of the melamine formaldehyde resin is 30-50%.

[0059] The preparation method step of described urea-formaldehyde resin is as follows:

[0060] Take formaldehyde and urea at a molar ratio of 1.05-2.0, and divide the urea into three batches; first, adjust the pH value to 7.5-8.5 with sodium hydroxide, add the first batch of urea, heat up to 80-95°C, and keep warm for 20-40min. Use ammonium chlor...

Embodiment 1

[0064] (1) Preparation of polymer nanocapsules:

[0065] 1) Mix 7 grams of methacrylic acid, 6 grams of methyl methacrylate, 0.3 grams of 4,4-azo-bis(4-cyanovaleric acid) and 2 grams of dodecyl-3-carbonitrile Trithio valeric acid was dissolved in 50 grams of dioxane solvent, and polymerized at 90° C. for 6 hours to obtain an amphiphilic macromolecular reversible addition scission chain transfer reagent. The structural formula is as follows:

[0066]

[0067] 2) 0.6 gram of the above-mentioned amphiphilic macromolecular reversible addition chain scission chain transfer reagent and 80 grams of deionized water are formulated into an aqueous solution as the water phase, and 1 gram of glycidyl methacrylate, 9 grams of p-vinylbenzene , 0.15 g of azobisisobutyronitrile and 10 g of paraffin oil phase and mixed uniformly, and prepared under the action of a high shear field by an ultrasonic pulverizer to obtain a miniemulsion.

[0068] 3) Move the mini-emulsion to the reactor, stop...

Embodiment 2～4

[0078] Examples 2-4 are the same as Example 1 except that the solid content of the nanocapsule emulsion is different. The solid contents of the nanocapsule emulsions used in Examples 2 to 4 were 20%, 25%, and 45%, respectively, and the specific property parameters of the prepared polymer nanoporous materials are shown in Table 2. From Table 2, it can be found that although the pore size distribution of the polymeric porous material is very wide, from nanometer to micron, by adjusting the solid content of the gelled emulsion, its average pore size (volume average) can be reduced to the order of nanometers, Such as image 3 shown. Since the heat transfer of nanopores is affected by the Knudsen Effect, the thermal conductivity of the gas phase can be significantly reduced. Although the porosity decreases, the thermal conductivity of the solid part will increase, but the results show that within a certain range, the polymer porous material shows a trend of decreasing thermal con...

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Abstract

The invention discloses a method for preparing super thermal isolation polymer materials from polymer nanometer hollow capsules. According to the method, firstly, hydrophilic and oleophilic macromolecular reversible addition fragmentation chain transfer reagents are used for preparing polymer nanometer capsules, then, inter-capsule cross linking agents are prepared, finally, the inter-capsule cross linking agents and the polymer nanometer capsule emulsion are mixed according to a mass ratio of capsule to inter-capsule cross linking agents of 2.5:1 to 0.8:1, the pH is regulated to be 3.0 to 6.8, the reaction lasts 30 minutes to 24 hours at the temperature being 60 to 90 DEG C, the emulsion is gelatinized, then, core paraffin wax in the nanometer capsules is replaced through tetrahydrofuran, and polymer nanometer porous materials are obtained through vacuum drying. The method has the advantages that the preparation process is simple, and the porosity and the pore size can be regulated through changing the solid content of the nanometer capsule emulsion, the consumption of etherified melamine formaldehyde resin and the self porosity of the nanometer hollow capsules. In addition, compared with the traditional thermal isolation materials, the porous materials have high mechanical strength.

Description

technical field [0001] The invention relates to a method for preparing a super heat-insulating polymer material from polymer nanometer hollow capsules. Background technique [0002] It is generally believed that super insulation materials refer to insulation materials whose thermal conductivity is lower than that of "no convection air" under predetermined use conditions. According to its characteristics, the super heat insulating material is generally a nanoporous super heat insulating material, and its principle is as follows. [0003] The heat transfer of porous materials (λ t ) is mainly composed of the solid phase part (λ s ), gas phase part (λ g ) and the radiation part (λ r ) composition, as shown in formula 1: [0004] lambda t =λ s +λ g +λ r +coupling term. (1) [0005] Thermal radiation is relatively small in most applications and can be ignored. Therefore, we only consider the conduction of heat in the two phases of the porous material, namely λ s +λ ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/26C08J3/24C08G12/38C08G12/12C08F212/36C08F220/32C08F212/08C08F212/14C08F222/14C08F2/38B01J13/14
Inventor 罗英武高翔叶长怀
Owner ZHEJIANG UNIV
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