【作者】 汤滢；

【导师】 谢长生； 夏先平；

【作者基本信息】 华中科技大学 ， 材料学， 2011， 硕士

【摘要】 传统的宫内节育器(Intrauterine Device, IUD)是在含有硫酸钡作为显影剂的聚乙烯支架上载有铜丝或铜管的分离结构,其铜离子释放速率的调节只能通过改变带铜面积来实现。而新型IUD使用的是铜/低密度聚乙烯(Cu/LDPE)颗粒分散型复合材料,聚乙烯基体的骨架结构对铜离子有控释作用,因此其铜离子释放速率的调节可以通过复合材料的微结构调控来实现。作为IUD材料,临床上需要关注的性能主要包括铜离子释放、力学性能和生物相容性。本文主要从材料选择和生产工艺两个方面进行考虑,对Cu/LDPE复合材料进行微结构调控,以达到改善IUD材料上述性能的目的。此外,为改善材料的表面亲水性,本文还尝试利用紫外辐照处理对复合材料进行表面改性。材料选择方面的因素包括铜颗粒粒径及含量、聚乙烯粒径、致孔剂的种类和添加量等,其中致孔剂选用了NaCl、无水葡萄糖和可溶性淀粉这三种人体相容性好的物质。为研究铜离子释放性能,将各种复合材料试样浸泡在恒温37.5℃的模拟宫腔液中,利用紫外-可见分光光度计测定其每天的铜离子释放量。研究发现,Cu/LDPE复合材料在模拟宫腔液中的铜离子释放速率随着铜颗粒含量、粒径的增大和聚乙烯粒径的减小而增大,而各种致孔剂的添加都提高了复合材料的铜离子释放速率。力学性能测试是使用国家标准规定的拉伸试样在电子万能试验机上进行的,选取断裂伸长率、拉伸强度和弹性模量三个参数进行评价。测试结果表明,Cu/LDPE复合材料的力学性能随着铜含量、铜粒径及聚乙烯粒径的变化呈现出复杂的规律性,而致孔剂的添加均降低了复合材料的力学性能,其中添加NaCl时降幅最大。此外,还利用接触角仪测试了各种复合材料表面分别对水和模拟宫腔液的静态接触角,发现多数微结构调控对Cu/LDPE复合材料的表面亲水性影响甚微,只有致孔剂的添加对复合材料表面亲水性的改善效果显著。生产工艺方面主要考虑注塑温度和余料再加工次数,目的在于为IUD生产工艺的制定中注塑温度的选择和生产余料的回收再利用提供实验依据。研究表明,注塑温度对Cu/LDPE复合材料的各方面性能影响比较复杂,综合评价选定170℃为最佳注塑温度。经多次粉碎和注塑成型的Cu/LDPE复合材料各方面性能都很稳定,再加工次数对其力学性能和铜离子释放性能都不会产生显著的影响,因此在实际IUD生产中的余料再利用是完全可行的。在改善Cu/LDPE复合材料表面亲水性的探索性研究中发现,各种经过紫外辐照的复合材料对水的接触角出现大幅下降,说明紫外辐照可以用于提高复合材料的表面亲水性。此外,紫外辐照作为医疗器械普遍采用的灭菌方式,也可有效用于新型IUD的灭菌。综合考虑,紫外辐照作为新型IUD的一种后处理方式具有显著的现实意义。更多还原

【Abstract】 The traditional Intrauterine Device(IUD)is a T-shaped device consisting of several sections of copper wires or copper tubes wrapped around a polyethylene stem, which contains BaSO4 filler as developer, and the releasing rate of cupric ions can only be controlled by changing the surface area of copper. The novel IUDs are prepared by Cu/LDPE composites, whose copper particles are dispersed in the matrix of LDPE, and the control of the microstructure of composites is an effective method to regulate the releasing rate of cupric ions.As the material of IUDs, the major properties need attention in clinical are the release of cupric ions, the mechanical property and the biocompatibility. To improve the above properties of IUD materials, the selection of material and the process of production are two aspects that were taken into consideration to control the microstructure of Cu/LDPE composites. Besides, the UV irradiation was used in order to improve the surface hydrophilicity of materials in the present paper.The factors of material selection include the size and content of copper particles, the particle size of LDPE, and the types and amount of pore-forming agent. Sodium chloride, anhydrous glucose and soluble starch were chosen as three pore-forming agents because of their excellent body compatibility. In order to investigate the releasing property of cupric ions, variousγ-shaped Cu/LDPE composite IUDs were immersed in simulated uterine fluid with the constant temperature of 37.5℃, and the concentration of cupric ions was measured using the UV-Vis spectrophotometer. The results showed that, for the Cu/LDPE composite IUDs, the release amount of cupric ions increased with the increase of the content and size of copper particles and with the decrease of the particle size of LDPE. The addition of all the pore-forming agents increased the release amount of cupric ions. The mechanical properties of Cu/LDPE composites were investigated by means of tensile test using standard tensile samples. The elongation at break, the tensile strength, and the elastic modulus were three evaluating parameters. The testing results showed that, the mechanical property of Cu/LDPE composites exhibited a complex regularity with the changing of copper content and the particle size of copper and LDPE. The addition of various pore-forming agents all reduced the mechanical property of Cu/LDPE composites, especially NaCl. Besides, wetting ability of various composites was evaluated by measuring the static contact angle using distilled water and SUS. The result showed that, majority of microstructure control methods had few influence on improving the surface hydrophilicity of Cu/LDPE composites, except the addition of pore-forming agents.The factors of production technology include the injection molding temperature and reuse times of scrap, aiming at providing the experimental evidence for the choice of injection molding temperature and the recycle of the scrap. The result showed that, the influence of injection molding temperature on various properties of Cu/LDPE composites was quite complex, and 170℃was selected as the best injection molding temperature by comprehensive consideration. The properties of Cu/LDPE composites still kept stable after several times of repeating process, which indicated that repeating process wouldn’t reduce the mechanical property and cupric releasing property of material. Therefore, the recycle of scrap is feasible in practical production of IUDs.In the exploratory investigation of improving the surface hydrophilicity of Cu/LDPE composites, it was found that the contact angle of composites sharply decreased after UV irradiation, which suggested that UV irradiation can be used to improve the surface hydrophilicity of composites. Besides, as a commonly used sterilization method for medical devices, UV irradiation can also be used in the sterilization of the novel IUDs. In a word, UV irradiation is a potential post-treatment method for the novel composite IUDs.更多还原