Sustainable Polymers from Native Silicon

来自天然硅的可持续聚合物

• 批准号: 1904768
• 负责人: Stephen Miller
• 金额: $ 56.38万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1904768&HistoricalAwards=false
• 关键词: Sustainable; Polymers; Native; Silicon

With funding from the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Professor Stephen A. Miller of University of Florida is building sustainable polymers from silica (silicon oxide and sand) and organic molecules derived from renewable biomass feedstocks. Commodity plastics in today's society are largely derived from fossil fuels and contain as much as 80 percent of carbon. This is inconsistent with the elemental composition of earth's crust which contains only 0.02 percent carbon. This work focuses on the use of silica, which comprises nearly 60 percent of the terrestrial environment, to prepare large-scale polymers. Targeted polymerization strategies include multiple additions of silicon/oxygen based building blocks to form extended polymer chains with the content of silicon and oxygen ranging between 38 and 60 percent. This novel class of polymers yields materials with new properties and provides opportunities for tuning these polymers toward easy environmental degradation. The research associated with this award provides a solid training ground for the next generation of scientists. The project prepares the students for a world which follows the principles of sustainability. This research embraces various sustainability metrics. The inclusion of inexpensive silica into commodity plastics could accelerate the growth of sustainable polymers and widen the variety of materials applications. Professor Miller and his research team continue their strong commitment to training and mentoring of undergraduate students, many of whom are members of underrepresented groups in chemistry. This research focuses on the direct conversion of native silica and biobased diols to discrete alkylorthosilicate monomers. The silica depolymerization strategy specifically avoids costly redox chemistry and is optimized with improved phase transfer catalysts, in combination with elevated temperature, microwaves, or sonication. Direct monomer polymerization or alkylorthosilicate metathesis polymerization (ASMP) renders polyesters, polycarbonates, polyacetals, polyamides, and polyimides with a silicon+oxygen content ranging between 38 and 60 percent. Preparation and characterization of these novel polyalkylorthosilicates reveal insight into fundamental polymer structure/property relationships, along with improved understanding of how to manipulate the silicon-oxygen bond, which is enigmatic despite its ubiquity in the earth's crust. The synthesized polyalkylorthosilicates possess new material properties, including those impacted by the very strong silicon-oxygen bond. Additionally, confining the silicon-oxygen bond to a ring is expected to improve the glass transition temperature into the range of high-temperature packaging plastics. While molecular alkylorthosilicates are hydrolyzed over the course of hours, the hydrolysis of this functional group embedded in relatively hydrophobic polymers is predicted to be slower and tunable. Systematic studies associated with rates, pathways, and degradation products during polyalkylorthosilicate hydrolysis could enable facile environmental degradation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学部大分子、超分子和纳米化学项目的资助下，佛罗里达大学的Stephen A. Miller教授正在用二氧化硅（氧化硅和沙子）和来自可再生生物质原料的有机分子构建可持续聚合物。当今社会的商品塑料主要来自化石燃料，含有高达80%的碳。这与地壳的元素组成不一致，地壳只含有0.02%的碳。这项工作的重点是使用二氧化硅，它占陆地环境的近60%，来制备大规模聚合物。定向聚合策略包括多次添加硅/氧基构建块，形成硅和氧含量在38%至60%之间的延伸聚合物链。这种新型聚合物产生了具有新特性的材料，并为调整这些聚合物使其易于环境降解提供了机会。与该奖项相关的研究为下一代科学家提供了坚实的训练基础。该项目为学生们准备了一个遵循可持续性原则的世界。这项研究包含了各种可持续性指标。在商品塑料中加入廉价的二氧化硅可以加速可持续聚合物的增长，并扩大材料应用的种类。米勒教授和他的研究团队继续致力于培训和指导本科生，其中许多人是化学领域代表性不足的群体的成员。本研究的重点是将天然二氧化硅和生物基二醇直接转化为离散的烷基硅单体。二氧化硅解聚策略特别避免了昂贵的氧化还原化学反应，并通过改进的相转移催化剂，结合高温，微波或超声进行了优化。直接单体聚合或烷基硅酸甲酯复分解聚合（ASMP）可以合成硅+氧含量在38%到60%之间的聚酯、聚碳酸酯、聚缩醛、聚酰胺和聚酰亚胺。这些新型聚烷基硅酸盐的制备和表征揭示了对基本聚合物结构/性质关系的深入了解，以及对如何操纵硅-氧键的更好理解，尽管硅-氧键在地壳中无处不在，但它是一个谜。合成的聚烷基硅酸盐具有新的材料性能，包括受很强的硅氧键影响的性能。此外，将硅氧键限制在一个环上有望提高玻璃化转变温度，使其进入高温包装塑料的范围。虽然分子烷基硅酸盐的水解需要几个小时，但这种嵌入在相对疏水聚合物中的官能团的水解预计会更慢，而且是可调节的。系统地研究聚烷基硅水解过程中的速率、途径和降解产物，可以促进环境降解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Entropy-Driven Depolymerization of Poly(dimethylsiloxane)

聚二甲基硅氧烷的熵驱动解聚

• DOI: 10.1021/acs.macromol.2c02554
• 发表时间: 2023
• 期刊: Macromolecules
• 影响因子: 5.5
• 作者: Torgunrud, Jordan L.;Reverón Pérez, Aracelee M.;Spitzberg, Emily B.;Miller, Stephen A.
• 通讯作者: Miller, Stephen A.

Thermodynamics of silica depolymerization with alcohols

二氧化硅与醇解聚的热力学

• DOI: 10.1016/j.poly.2020.114562
• 发表时间: 2020
• 期刊: Polyhedron
• 影响因子: 2.6
• 作者: Torgunrud, Jordan L.;Faria, Alejandro J.;Miller, Stephen A.
• 通讯作者: Miller, Stephen A.