Release date: 2014-06-03
Author: Xu Shan Chinese Medical Device Industry Association
A rubber product that meets certain hygiene standards for the treatment of diseases in hospitals and for the replacement of certain organs or tissues in the human body. Can be divided into two categories of in vitro and in vivo. The rubber used is silicone rubber, natural rubber and PU (polyurethane). From the development trend of medical rubber products and the demand of the medical market, the variety, quantity and dosage are increasing, and the use is also expanding. In the future, with the continuous improvement of rubber processing technology and medical technology, it is believed that there will be better medical rubber products put into clinical application to meet the needs of the majority of patients.
Polyurethane
Polyurethane elastomer (PU) is a polar polymer composed of alternating segments of soft and hard segments and containing many -NHCOO groups. By selecting appropriate soft and hard segment structures and their proportions, A medical polymer material which has good physical and mechanical properties and is compatible with blood and biocompatibility. Among them, the polyurethane elastomer used in medical treatment is mainly a thermoplastic polyurethane (TPU) elastomer. TPU is a linear block polymer composed of a soft segment (long-chain oligodiol) and (diisocyanate and chain extender), and the soft and hard segments in the molecular structure of the polyurethane have polar compatibility. Due to its convenient processing and excellent performance, TPU has been widely used in the preparation of a variety of medical and health care products.
Polyurethane properties:
The wide application of polyurethane elastomers in the biomedical field is inseparable from its excellent performance. Its main properties are: (1) excellent coagulation performance; (2) toxicity test results meet medical requirements; (3) good biocompatibility in clinical application, no distortion, no allergic reaction, can solve natural latex medical products Inherent "protein allergy" and "carcinogenic nitrosamine precipitation" two major problems, which become a replacement material for many natural latex medical products; (4) has excellent toughness and elasticity, good processing performance, processing variety, is the production Preferred materials for various medical elastomer products; (5) Excellent wear resistance, soft touch, moisture resistance, and resistance to various chemicals; (6) Can be sterilized by the usual method and exposed to γ-rays. constant.
The application of polyurethane in medicine:
Since the first application of polyurethane in biomedicine in the 1950s, the use of polyurethane elastomers in medicine has become increasingly widespread for more than 40 years. In 1958, polyurethane was first used in fracture repair materials and was successfully applied to supplemental coatings for vascular surgical sutures. Polychlorate has received much attention as a medical material since the 1970s. In the 1980s, the successful use of polyurethane elastomers for artificial heart transplants led to the further development of polyurethane materials in biomedical applications.
Currently in medical applications, especially in the manufacture of a variety of medical supplies implanted in the human body, applications include artificial heart valves, artificial lungs, bone adhesives, artificial skin and burn dressings, cardiac pacemaker leads, Sutures, various splints, catheters, artificial blood vessels, trachea, intubation, dental materials, family planning supplies, etc. The medical applications of polyurethane elastomer materials are shown in the table.
With the widening of the use of polyurethane in the field of medical biology, the disadvantage that polyurethane can not be naturally degraded is increasingly becoming an obstacle to its development, which brings about the problem of waste polluting the environment. Therefore, the development of biodegradable polyurethane materials has become a solution to this problem. The key to the puzzle. The biodegradable polyurethanes that have been developed mainly include the following: (1) oligosaccharide-derived polyurethane; (2) lignin, tannin and bark-derived polyurethane; (3) cellulose-derived polyurethane; (4) starch Derivatized polyurethane; (5) Other types of biodegradable polyurethane. The process of biodegradation of polyurethane can be divided into two stages: (1) the degradation of natural polymer compounds causes the polyurethane to form many micropores on the surface; and (2) the micropores produced make the microorganisms easily invade the natural macromolecular compounds inside. Micropores are formed inside to accelerate the degradation of the polyurethane until the polyurethane is completely degraded. Due to the good biocompatibility and antithrombotic properties of polyurethanes, biodegradable polyurethanes have great potential for development in the biomedical field.
The polyurethane with memory function is called room temperature shape memory polyurethane, and its working principle is to realize the shape memory process by utilizing the difference of the glass transition temperature between the hard segment and the soft segment. It can be used to make various orthopedic and conformal articles, such as dental orthoses, orthopedic orthoses, bandages, bras, belts, etc., which can be made into the desired shape and then reheated to restore the original shape when used. Thereby achieving the desired effect. Shape memory polyurethane has broad application prospects, but it has high cost and poor processability, and it is still difficult to achieve generalization. In terms of its development, the accuracy of improving its recovery shape temperature should be the focus of research. Shape memory products are only usable if the temperature is accurately restored.
At present, the development of TPU in the field of medical and health is rapidly developing in bioengineering, cell engineering, and immunoengineering. In the long run, tissue engineering is a new direction for rapid development in biomedical engineering. The core of this cross-disciplinary science is the application of biological and engineering principles and methods to develop biologically active artificial substitutes for maintenance and restoration. Or improve the body's tissue function. Therefore, in order to achieve longer-term development, it is necessary to modify the biological material of polyurethane to adapt to the development of tissue engineering.
Polyurethane application status and development trend:
Compared with similar foreign products, the domestic medical polyurethane elastomer research and development still has shortcomings such as small variety, small scale and high price. Polyurethane only accounts for a small share. Medical polyoxyester materials in the United States and other countries have already been commercialized. New materials and new uses are still under development. Medical products have strict requirements on the performance of synthetic materials. The research needs to support the medical value alone.
Many domestic units have been engaged in or are engaged in the research of medical polyurethanes, such as Shanxi Institute of Chemical Industry, Zhongshan University, Shanghai Rubber Industry Products Research Institute, Jiangsu Chemical Industry Research Institute. However, the promotion and application are not enough, and the impact is not big. Compared with developed countries, there is a big gap. Therefore, independent innovation, cost reduction, high-performance, serialized, large-scale medical polyurethane elastomer research and development, has become the development direction of the domestic medical polyurethane industry. Currently representative medical polyurethane products in foreign countries, see table.
Source: China Medical Device Industry Association
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