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Novel reversible covalent cross-linked thermoplastic polyurethane

A technology of thermoplastic polyurethane and covalent crosslinking, which is applied in the field of thermoreversible thermoplastic polyurethane materials, can solve the problems of use and inability to use materials, and achieve the effects of wide application prospects, high input-output ratio, and simple and convenient process

Inactive Publication Date: 2014-11-05
NANKAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, because it is only a change in molecular weight, the DA reaction does not provide additional mechanical properties for the system, so it cannot be used as a material

Method used

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  • Novel reversible covalent cross-linked thermoplastic polyurethane
  • Novel reversible covalent cross-linked thermoplastic polyurethane
  • Novel reversible covalent cross-linked thermoplastic polyurethane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] A preparation method based on novel reversible covalently crosslinked thermoplastic polyurethane, comprising the steps of:

[0029] 1) Add organic solvent 5mL N,N'-dimethylacetamide DMAc, 6 drops of stannous isooctanoate, 4.805g of 4,4'-diphenylmethane diisocyanate MDI to dissolve in a dry and clean reaction kettle to obtain liquid a;

[0030] 2) Dissolve 9.183g of polytetrahydrofuran glycol PTMG with a molecular weight of 2000 in 80mL of DMAc to obtain liquid b;

[0031] 3) Slowly add solution b to solution a, and react at a temperature of 30°C to 80°C for 1-5 hours to obtain a prepolymerized product;

[0032] 4) Add 2.5g of N-(2,3-dihydroxypropyl)maleimide (DHMI) chain extender to the above prepolymerization product, and keep it warm for 1-10 hours;

[0033] 5) Add 2.6g of FHF according to the molar ratio of Diels-Alder reaction functional group 1:1, and react at 0-100°C for 1-3 days to complete the Diels-Alder reaction. The structural formula of FHF is as follows

...

Embodiment 2

[0038] A method for preparing reversibly covalently crosslinked thermoplastic polyurethane based on a novel chain extender, comprising the steps of:

[0039] 1) Add 5mL of organic solvent N,N'-dimethylacetamide DMAc, 6 drops of stannous isooctanoate, and 3.229g of hexamethylene diisocyanate HDI to dissolve in a dry and clean reactor to obtain liquid a;

[0040] 2) Dissolve 9.183 g of polycyclocaprolactone diol PCL with a molecular weight of 2000 in 80 mL of DMAc to obtain liquid b;

[0041] 3) Slowly add solution b to solution a, and react at a temperature of 60°C to 110°C for 1 to 5 hours to obtain a prepolymerized product;

[0042] 4) Add 1.25g N-(2,3-dihydroxypropyl)maleimide (DHMI) chain extender and 0.658g traditional chain extender 1,4-butanediol (BDO) to the above prepolymerization product ) mixture, heat preservation reaction 1-10h;

[0043] 5) According to the Diels-Alder reaction functional group molar ratio 1:1, add 1.59gFMF, and react at a temperature lower than ...

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Abstract

The invention provides novel reversible covalent cross-linked thermoplastic polyurethane. The class of polyurethanes comprises a dienophile (or diene) novel chain extendor or hybrid chain extendor located in a hard segment, and a certain proportion of diene (or dienophile) cross-linking agent of polyfunctionality. The diene and the dienophile undergo Dienls-Alder reaction within a preset temperature range so that the originally thermoplastic polyurethane generates covalent cross-linking, and a covalent cross-linking bond can generate reverse reaction within a certain temperature range to cause the material to recover to the original non-cross-linked structure so that the material can be reprocessed. Compared with common thermoplasticity, the polyurethane prepared by the invention which is cross-linked at room temperature has excellent mechanical property and solvent resistance, a network structure is formed in the material under the cross-linking action so that the hardness, compactness and application temperature range of the material are obviously improved, and the material performance can be continuously regulated within a very wide range by simply regulating the use amount of the cross-linking agent.

Description

technical field [0001] The present invention relates to a thermoreversible thermoplastic polyurethane material with covalent crosslinking properties. Background technique [0002] Thermosetting polyurethane has better solvent resistance, shear resistance, permanent deformation resistance, higher material hardness, softening temperature and elastic modulus, so in the industrial field, thermosetting polyurethane occupies an absolute position in terms of usage and application fields Advantage. However, thermosetting materials have the fatal disadvantage of being non-reprocessable. Due to the high cost of polyurethane, the non-reprocessability of materials has caused a lot of waste in many fields. Matějka et al. studied the addition of excess isocyanate and urethane bonds in the polyurethane system to form a three-dimensional crosslinked structure of allophanate to enhance the limit properties of polyurethane and obtained good results. However, due to the excess of isocyanate i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G18/66C08G18/48C08G18/42C08G18/32C08J3/24C08L75/08C08L75/06
Inventor 孙平川于深何鑫
Owner NANKAI UNIV