Thermotropic crosslinking type shape memory polyurethane material and preparation method thereof

Abstract

The invention discloses a thermotropic crosslinking type shape memory polyurethane material obtained by thermal crosslinking of thermoplastic polyurethane with a side-chain double bond, a bifunctional crosslinking agent and an initiator; in a bending mode, the shape fixed rate is more than or equal to 95%, and the shape recovery rate is more than or equal to 90%; in a dynamic mechanical analysis tensile mode, the shape fixed rate is more than or equal to 95%, and the shape recovery rate is more than or equal to 90%. A preparation method disclosed by the invention is a second-step method and comprises the steps: firstly preparing the thermoplastic polyurethane with the side-chain double bond, then carrying out melting mixing or solution mixing with the bifunctional crosslinking agent under a condition with addition of the initiator, and carrying out thermal crosslinking to prepare the product. The polyurethane material disclosed by the invention has excellent shape memory properties and mechanical properties, the transition temperature is close to a body temperature, and the raw materials have good biological compatibility and no toxicity and can be degraded; the polyurethane material can be used as in-vivo implant materials and clinical surgical materials, also can be used for wire and cable casings and building pipe connecting sleeves, moreover, can be used for buffer sole protection devices, deformation toys and the like, and is suitable for large-scale industrialized production.

Description

technical field [0001] The invention belongs to the technical field of thermotropic shape-memory polymer material and its preparation, and in particular relates to a thermotropic cross-linked shape-memory polyurethane material and a preparation method thereof. Background technique [0002] Shape memory polymers (Shape Memory Polymers, SMPs), as a new type of stimuli-responsive polymer materials, have attracted extensive attention of researchers in recent years. This kind of SMPs, which has the ability to change its shape under the action of external stimuli, is gradually expected to become an effective substitute for shape memory alloys (Shape Memory Alloys, SMA). The temperature is wide and easy to adjust, the recovery rate is high, the cycle is good, the weight is light and cheap, and the processing is convenient. It can be widely used in aerospace, engineering, medical and other fields, as well as residents' daily necessities. [0003] Shape memory polyurethanes (Shape M...

AI Technical Summary

Problems solved by technology

In this regard, K. Hearon et al. (Journal of Applied Polymer Science, 121(2011), 144–153) used radiation to crosslink thermoplastic polyurethanes containing 1,4-butenediol chain extension to obtain crosslinked shape memory polyurethanes. , but in addition to using special electron or cobalt source irradiation equipment, radiation crosslinking has strict requirements on the thickness and shape of irradiated plastic products. For example, the material prepared in this document is only a 1mm film, because the sample is too thick It will affect the transmittance of rays, resulting in low and uneven crosslinking. Therefore, the preparation of crosslinked shape memory polyurethane materials by radiation method seriously limits the mass production and application of materials.