Abstract：
Poly (methyl methacrylate) (PMMA) is a synthetic polymer commonly used for medical implants in cranioplasty and orthopedic surgery owing to its excellent mechanical properties, optical transparency, and minimal inflammatory responses. Recently, the development of 3D printing opens new avenues in the fabrication of patient-specific PMMA implants for personalized medicine. However, challenges are confronted when adapting medical-grade PMMA to the 3D printing process due to its dynamic viscosity and nonself-supporting characteristics before cured. In addition, the intrinsically exothermic polymerization of MMA brings about bubble generation issues that reduce its mechanical performance harshly. Therefore, in this study, an embedded 3D printing methodology followed by pressurized thermo-curing is proposed and developed: a granular alginate microgel is designed for serving as a supporting matrix when jamming formed between the granules to structurally support the extruded precursor filaments of PMMA-MMA ink during both 3D printing and post-curing; moreover, the autoclave reactor enclosing the alginate matrix and as-sculpted PMMA structures is utilized to generate temperature-dependent pressure, which serves for suppressing the bubbles and solidifying the polymerized MMA during the post-curing process. The 3D printed PMMA is comparably matchable to traditional PMMA castings in terms of their microstructures, density, thermal properties, mechanical performance and biocompatibility. In the future, the proposed embedded 3D printing platform combined with the special post-curing method has great potential for a customized and cost-effective fabrication of patient-specific, complex and functional PMMA implants.
摘要：
聚（甲基丙烯酸甲酯）（PMMA）是一种合成聚合物，由于其优异的机械性能，通常用于颅骨修补术和骨科手术中的医疗植入物，光学透明度，和最小的炎症反应。最近,3D打印的发展为个性化医疗的患者专用PMMA植入物的制造开辟了新的途径。然而,由于其动态粘度和固化前的非自支撑特性，使医用级PMMA适应3D打印工艺时面临挑战。此外,MMA的本质放热聚合带来了气泡产生问题，严重降低了其机械性能。因此,在这项研究中，提出并开发了一种嵌入式3D打印方法，然后进行加压热固化：设计了一种颗粒状藻酸盐微凝胶，用于在颗粒之间形成干扰时用作支撑基质，以在3D打印和后固化期间在结构上支撑PMMA-MMA墨水的挤出前体长丝;此外，高压釜反应器封闭的藻酸盐基质和雕刻的PMMA结构用于产生温度依赖性压力，其用于在后固化过程中抑制气泡和固化聚合的MMA。3D打印的PMMA在微观结构方面与传统的PMMA铸件相当。密度,热性能，机械性能和生物相容性。在未来,所提出的嵌入式3D打印平台与特殊的后固化方法相结合，在定制和经济高效的患者专用制造方面具有巨大潜力，复杂和功能性PMMA植入物。
