SBIR Phase II: Ultra-softening polymers from engineered thiol-based resins for additive manufacturing

这个小企业创新研究（SBIR）第二阶段项目的更广泛的影响/商业潜力是制造可以通过增材工艺直接制造的坚韧的3D打印部件。增材制造有可能通过简化产品设计、生产和验证来彻底改变零件的生产方式，从而降低生产成本并缩短交货时间。增材技术在工业过程中的渗透已经大大减缓，因为目前无法3D打印任何刚度的零件，其材料性能与传统制造的零件相当。特别地，3D打印材料倾向于在连续的打印层之间更容易撕裂或破裂。在Adaptive 3D Technologies，我们开发了树脂，通过在打印层之间实现共价交联，可以生产坚韧耐用的部件，这些部件在x，y和z平面上比许多当前的3D打印产品更坚固。这些材料和加工技术将有助于推动增材制造进入大批量但可定制的市场领域，以提高各行业的效率和生产力。 由我们的可打印材料制成的打印部件将通过降低生产成本、提高产品性能和回流先进制造业，进一步推动美国制造业的发展。该项目的重点是了解一类特殊的低粘度硫醇烯树脂中的界面化学和粘附现象，以生产一系列可通过立体光刻（SLA）进行3D打印的机械坚韧材料。当前SLA方法的一个显著问题是连续的印刷层不能充分地粘附在一起，导致韧性的大幅降低，如通过软、粘弹性和刚性材料中的应力-应变响应所测量的。我们的第二阶段研究探索了分子结构、反应性、树脂粘度和关键打印参数之间的权衡，以开发改进的材料，从而在类似的打印速度和远低于100微米的特征尺寸下，实现比行业标准沿着多个变形轴更坚固的打印部件。我们开发了一系列3D打印材料，其室温杨氏模量接近2 MPa，20 MPa，200 MPa或2 GPa。 软质和粘弹性材料在所有印刷方向上具有远高于100%的应变能力，包括当垂直于印刷层界面测量时。我们希望通过在我们的系统中加入适当的添加剂来控制颜色、保质期、美观性、机械性能和与各种喷射技术的兼容性，从而通过拟议的第二阶段SBIR努力进一步提高我们聚合物的热机械性能。

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project is making tough, 3D printed parts that can be directly manufactured through additive processes commercially available. Additive manufacturing has potential to revolutionize the way parts are produced by streamlining product design, production, and validation, which allows for low production costs and accelerated lead times. The penetration of additive technology into industrial processes has been greatly slowed by the current inability to 3D print parts of any stiffness with materials properties on par with traditionally manufactured parts. Particularly, 3D printed materials tend to tear or fracture more readily between successive printed layers. At Adaptive 3D Technologies, we have developed resins that produce tough, robust parts that are tougher than many current 3D printed products in the x, y and z planes by achieving covalent crosslinking across printed layers. These materials and processing techniques will help drive additive manufacturing into large volume, yet customizable, market sectors to increase efficiency and productivity across industries. The printed parts resulting from our printable materials will further U.S. manufacturing by lowering production costs, increasing product performance and reshoring advanced manufacturing. This project is focused on understanding interface chemistry and adhesion phenomena in a special class of low-viscosity, thiol-ene resins to produce a range of mechanically tough materials that are 3D printable via stereolithography (SLA). A significant problem with current SLA approaches is that successive printed layers do not adhere sufficiently together, leading to large reductions in toughness as measured by the stress-strain response in soft, viscoelastic and stiff materials. Our Phase II research explores the tradeoffs between molecular architecture, reactivity, resin viscosity, and key printing parameters to develop improved materials to enable tougher printed parts than industry standards along multiple axes of deformation at similar printing speeds and feature sizes well below 100 microns. We have developed a portfolio of 3D printable materials with room temperature Young's moduli near 2 MPa, 20 MPa, 200 MPa or 2 GPa. Soft and viscoelastic materials have strain capacities well above 100% in all print directions, including when measured perpendicular to print layer interfaces. We expect to further our polymers' thermomechanical properties through the proposed Phase II SBIR effort by incorporating proper additives into our systems to control color, shelf life, aesthetics, mechanical properties and compatibility with various jetting techniques.