Titanium/polymer sheets designed for biomedical applications

该项目涉及用于生物医学应用的新型Ti/聚合物(P)/Ti和P/Ti/P片材的设计，控制其界面并调整其机械性能和成型行为。精化、工艺开发、特性分析及其形成限制将在三个合作伙伴之间协同进行，目标是：1。开发在夹层板（SMs）中设计P/Ti界面的策略，采用表面受限、无树脂兼容的聚合物层作为粘合剂，在P和Ti之间建立牢固的粘合，从而实现最终成型而不分层。将使用“从接枝”和“接枝到”方法，允许更多的单体选择。通过设计所选聚合物的玻璃化转变温度，在聚合物中“接枝”制备具有调制性质的Ti/P/Ti SMs。聚合引发剂将通过磷酸盐锚接枝在氢氧化钠修饰的钛表面。各种摩尔质量的线性聚合物链，如均聚物或共聚物类型，将通过控制自由基聚合过程从引发剂生长出来。使用的单体有甲基丙烯酸甲酯（MMA）、甲基丙烯酸正丁酯（nBMA）和丙烯酸甲酯（MA）。单体的混合物将用于合成无规共聚物。在Ti上“接枝”具有生物活性的厚聚合物层及4-苯乙烯磺酸钠（NaSS）和MA的共聚物。将使用一种易于获取的锚，它既包含锚定基团（儿茶酚），能够形成坚固、稳定的单层，又包含可点击的功能，允许对Ti表面进行模块化和高效的后功能化。与此同时，含有巯基的聚合物或共聚物将使用噻吩点击反应附着在单层上。不同摩尔质量的线性聚合物链，如同质聚合物或共聚物类型，可以通过控制自由基聚合合成得到巯基端。为了得到巯基端聚合物或共聚物，可以选择加成-破碎转移聚合。所使用的单体将是NaSS和/或MMA以及单体的混合物来合成统计共聚物。Ti/P/Ti或P/Ti/P复合材料的制备SMs将在IMET通过将改性Ti片粘合到商业或实验室制造的定义厚度的聚合物箔（例如PMMA或PMMA-co- pbma箔或PMMA-co- pnass箔）来处理。“嫁接”方法的可行性已在之前的项目中进行了说明。将机械性能调整到接近骨头的水平。机械和成型性能将通过调节聚合物的分子和结构参数或层厚的比例来研究和控制。将对其稳定性和细胞相容性进行研究。这些可用于颅骨成形术和下颌骨手术的系统的优点是重量轻，机械性能可设计在骨骼的范围内，与钛相比，热性能和声学性能得到改善。

The project deals with the design of new Ti/polymer(P)/Ti and P/Ti/P sheets for biomedical applications, controlling their interface and adjusting their mechanical properties and shaping behaviour. Elaboration, process development, analysis of the properties, and their forming limits will be performed in synergy between three partners with the goals:1. Developing strategies to design P/Ti interfaces in sandwich sheets (SMs) to employ surface-confined, resin free compatible polymer layers as adhesives for a strong bond between P and Ti for final shaping without delamination. “Grafting from” and “Grafting to” methods will be used, allowing a larger choice of monomers. “Grafting from” to produce Ti/P/Ti SMs with modulated properties in polymer by designing the glass transition temperature of the selected polymer. A polymerization initiator will be grafted at NaOH modified-Ti surface via a phosphonate anchor. Linear polymer chains of various molar masses, as homopolymers or copolymers types will be grown from the initiator using a controlled radical polymerization process. The monomers used will be as methyl methacrylate (MMA), n-butyl methacrylate (nBMA) and methyl acrylate (MA). A mixture of monomers will be used for the synthesis of random copolymers..“Grafting to” for bioactive thick polymer layers on Ti of homo and copolymers of sodium 4-styrenesulfonate (NaSS) and MA. A readily accessible anchor incorporating both an anchoring group (catechol), capable of forming a robust, stable monolayer, and a clickable function allowing the modular and efficient post-functionalization of the Ti surface will be used. In parallel, polymers or copolymers bearing thiol end groups will be attached using thiolene click reaction onto the monolayer. Linear polymer chains of various molar masses, as homo-polymers or co-polymers types will be synthetized by a controlled radical polymerization to give thiol-ends. In order to obtain thiol end polymers or copolymers, addition-fragmentation transfer polymerization will be chosen. The monomers used will be NaSS and/or MMA and a mixture of monomers to synthetize statistical copolymers.2. Fabricating Ti/P/Ti or P/Ti/P SMs; SMs will be processed at IMET by bonding modified Ti sheets to commercially or in laboratory made polymer foils of defined thicknesses (e.g. PMMA or PMMA-co-PBMA foils or PMMA-co-PNaSS foil). The feasibility of the “Grafting from” method was stated in a preceding project.3. Tailoring the mechanical properties close to the bones’ ones. Mechanical and shaping properties will be studied and controlled by modulating the molecular and structural parameters of the polymers or the ratio of the layer thicknesses.4. Stability and cytocompatibility of the SMs will be conducted.The advantages of these systems usable for cranioplasty and mandible surgery will be lightweight SMs with mechanical properties designable in the range of bones’ ones and improved thermal and acoustic properties compared to Ti.