SBIR Phase I: Smart Two-Way Shape Memory Polymer Based Sealant

这个小企业创新研究的第一期项目旨在提供一种价格合理的密封胶，用于密封混凝土路面、桥面等的伸缩缝和裂缝。在交通基础设施中，故意构造伸缩缝，以便在温度升高时结构元件由于线性热膨胀而移动。此外，裂缝是路面常见的破坏形式。如果密封不当，水的渗透会破坏表层和下面的层，被困的碎片会导致混凝土墙破裂。因此，密封裂缝和接缝是保持或延长结构使用寿命的常用做法。各类密封剂每年的市场价值约为61亿元。不幸的是，许多密封剂不能正确地密封裂缝和接缝，并且/或持续很长时间，需要经常更换或重新密封。在这个项目中，一种智能密封胶在冷却时膨胀，在加热时收缩，这与混凝土的热相反，将被开发出来，以抵消连接结构元素的热运动。本项目的智力优势在于智能密封胶技术的可行性。接缝失效的主要原因是大多数密封胶的行为与混凝土相似，即它们在冷却时收缩，在加热时膨胀。这种热性能与密封剂的要求是相反的。该项目的目的是设计、合成、表征和评估一种具有成本效益的双向形状记忆聚合物密封胶，用于密封混凝土路面或桥面的伸缩缝或裂缝，这种密封胶在冷却时会膨胀，在加热时会收缩。它将具有所需的机械性能和耐久性，以承受反复的交通负荷和室外环境。该项目的成功不仅对交通基础设施，而且对其他结构，如车道、停车场、水坝、港口、建筑物、游泳池等都有有益的影响。

This Small Business Innovation Research Phase I project aims to provide an affordable sealant for sealing expansion joints and cracks in concrete pavement, bridge deck, etc. In transportation infrastructure, expansion joints are intentionally constructed in order to allow movement of the structural elements due to linear thermal expansion when temperature rises. In addition, cracks are a common failure mode in pavement. If they are not properly sealed, water penetration will damage the surface layer and the layers beneath, and entrapped debris will cause rupture of the concrete wall. Therefore, sealing cracks and joints is a common practice to maintain or extend the structure service life. Various types of sealants have been used with an annual market value about $6.1 billion. Unfortunately, many sealants cannot properly seal cracks and joints, and/or last long, requiring frequent replacement or resealing. In this project, a smart sealant that expands upon cooling and contracts upon heating, which is thermally opposite to concrete, will be developed to counteract thermal movement of the joined structural elements. The intellectual merit of this project lies in the feasibility of a smart sealant technology. The primary reason for joint failure is that most sealants behave similar to concrete, i.e., they contract upon cooling and expand upon heating. This thermal behavior is contrary to the requirement for sealants. The objective of this project is to design, synthesize, characterize, and evaluate a cost-effective two-way shape memory polymer based sealant for sealing expansion joints or cracks in concrete pavement or bridge deck, which will expand upon cooling and contract upon heating. It will have the required mechanical properties and durability to survive the repeated traffic load and outdoor environment. The success of the project can have beneficial impact not only on the transportation infrastructure but also other structures such as driveways, parking lots, dams, harbors, buildings, swimming pools, etc.