One-step synthesis method for polyurethane material with gradually-changing modulus

Abstract

The invention provides a one-step synthesis method for a polyurethane material with gradually-changing modulus. The prepared polyurethane material with gradually-changing modulus is an interpenetrating polymer network material with a gradually-changing component; the component is a single polyurethane component; and the polyurethane material does not contain an interface, and the elastic modulus and all the other physical properties of the polyurethane material continuously change along a length direction in a same sample. A highly cross-linked polymer network is composed of hard cross-linking points with large sizes and flexible short chains with prescribed length; and even without addition of a plasticizer and a filling material, the elastic modulus of the system is allowed to vary in a wide scope by changing the sizes of the cross-linking points. The synthesis method overcomes the problem of difficult block copolymerization process caused by great increase of system viscosity in a urethane formation phase in a two-step method and the problem of complex steps like dipping of a carrier, drying of the carrier after dipping and removal of a solvent in a manufacturing of a composite material via a solution method; and the synthesis method has high efficiency, is environment-friendly and has high industrial feasibility.

Description

technical field [0001] The invention relates to a preparation method of a polymer gradient material, in particular to a one-step synthesis of a polyurethane modulus gradient material whose modulus and other physical properties can change continuously along the length direction in the same sample and does not contain an interface Law. Background technique [0002] In order to break through the constraints and deficiencies brought about by homogeneous materials, new aerospace materials have been developed to make them have more excellent performance to meet the long-term normal work in extreme environments. Japanese researchers put forward the new concept of tilted functional materials. The remarkable feature of this material is that the composition structure and physical parameters are continuously changing. The basic idea is to select two materials with different properties according to the specific use requirements, and to make the internal interface of the composite mater...

AI Technical Summary

Problems solved by technology

However, there are some defects in the two-step synthesis method: (1) The preparation of the modulus gradient material is a collection of rather long unit operations, and the viscosity of the system has a large increase in the urethane formation stage, which makes the block copolymerization process difficult. Difficulty; (2) In the manufacture of composite materials, the carrier needs to be impregnated by the solution method, and then dried to remove the solvent after impregnation; (3) There are many reaction steps, and the reaction time and curing time are long; (4) Increased and The probability of air contact and the high reaction curing temperature increase the side reaction

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