SBIR Phase I: Surface Modified Ground Tire Rubber for Additives of Asphalt Based Shingles

这个小型企业创新研究第一阶段项目涉及对研磨轮胎橡胶(GTR)颗粒进行表面改性，使GTR能够作为沥青的添加剂用于屋面瓦片，并改进其在铺路中的使用。这种添加剂取代了目前使用的昂贵的全聚合物添加剂，同时利用了一种原本就是废物的商品。现有的工艺会降低GTR，消耗过多的能源，成本很高，如果发生脱硫化，还会降低GTR的弹性。总而言之，这使得最终产品不适合用于屋面瓦片，并降低了其在铺设沥青方面的性能。这项研究的目的是为当前的技术开发替代方法。这一建议的智能优点来自于通过点击化学和原子转移自由基聚合(ATRP)相结合的方法对GTR颗粒进行聚合物表面修饰的相关研究，这种聚合物具有相当高的耐温性。预期的结果和优点包括：简化了表面涂覆工艺，减少了沥青混合料中GTR颗粒的降解，优化了橡胶沥青混合料的粘弹性性能，缩短了搅拌周期，降低了成本和能源，改善了橡胶颗粒在沥青中的分散性和兼容性。该项目的更广泛的影响/商业潜力将源于成功开发出一种低成本、高质量、高分散性、热稳定性的沥青添加剂。它将基于表面改性地面轮胎橡胶(GTR)，使灵活、耐用、高质量的屋顶材料和增强型铺装沥青得以开发。聚合物包覆的GTR颗粒提供了聚合物添加剂的优点，但使用的聚合物要少得多。仅商业聚合物就被用于屋顶和路面的沥青混合物中，但成本很高，目前的市场价格为每磅1.50美元至1.80美元。相比之下，添加GTR颗粒的成本仅为每磅0.25美元。初步估计，用聚合物涂层对GTR颗粒进行表面修饰的成本比材料成本高出约30%。通过减少和/或替代目前使用的昂贵聚合物添加剂的数量，将表面涂覆的GTR颗粒加入到屋面混合物中，可将生产成本降低高达20%。这些前驱体材料可在商业上以低成本获得。除了增强性能和低成本外，使用GTR颗粒还将提供环境效益，允许重复使用通常处置在垃圾填埋场的轮胎橡胶废料，并大幅减少对不可再生资源的使用。

This Small Business Innovation Research Phase I project relates to the application of a surface modification to ground tire rubber (GTR) particles, enabling use of GTR as an additive to asphalt for roofing shingles, and improving its use in paving. This additive replaces the costly all-polymer additives currently used, while making use of an otherwise waste commodity. Existing processes degrade the GTR, consume excessive energy, are high-cost, and decrease the elasticity of the GTR if devulcanization occurs. Altogether, this makes the final product unsuitable for use in roofing shingles, and reduces its performance in paving asphalt. The objective of this research is to develop alternative approaches to the current technology. The intellectual merit of this proposal arises from the research related to polymer surface modification of GTR particles via a combination click chemistry and atom transfer radical polymerization (ATRP), with a polymer having considerable temperature resistance. The anticipated results and advantages include: simplification of the surface coating process, reduced degradation of the GTR particles in an asphalt compound, optimization of the viscoelastic properties of the rubber-asphalt mixture, shortening of the mixing period, reduction of the cost and energy, and improved dispersion and compatibility of rubber particles within the asphalt.The broader impact/commercial potential of this project will stem from the successful development of a low cost, high quality, thermally stable asphalt additive with high dispersibility. It will be based on surface modified Ground Tire Rubber (GTR), enabling the development of flexible, durable, high-quality roofing materials, and enhanced paving asphalt. The polymer coated GTR particles provide the advantages of a polymer additive, but using far less polymer. Commercial polymers alone have been incorporated into mixtures of asphalt for roofing and pavement, but at high cost, with current market prices of $1.50 to $1.80 per pound. In contrast, the addition of GTR particles would cost only $0.25 per pound. The initial estimated cost to surface modify the GTR particles with a polymer coating has been calculated to be ~30% above material cost. The incorporation of surface-coated GTR particles into the roofing mixture reduces the production cost up to ~20% by reducing and/or substituting the amount of expensive polymer additives currently used. The precursor materials are commercially available at low cost. Aside from enhanced performance, and low cost, using GTR particles will provide an environmental benefit, allowing reuse of tire rubber waste typically disposed in landfills, and substantially reduces use of a nonrenewable resource.