Dissolution Processing of Nanostructured Polymers Tailored for Effective Utilization of Cellulosics

为有效利用纤维素而定制的纳米结构聚合物的溶解加工

• 批准号: 1159981
• 负责人: Marina Tsianou
• 金额: $ 39.8万
• 依托单位: SUNY at Buffalo
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-15 至 2017-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1159981&HistoricalAwards=false
• 关键词: Dissolution; Processing; Nanostructured; Polymers; Tailored

Intellectual Merit: The proposed research addresses the outstanding need for an integrated approach to dissolve cellulosics, an abundant and renewable resource, as an essential step for their processing into functional polymers, specialty chemicals, and biofuels. While several approaches have proven useful for activation of crystalline cellulose, the search is still on for solvents that can effectively dissolve cellulose. The few known solvents that are capable of dissolving cellulose do so under strict and often conflicting composition and temperature conditions, and fundamental understanding is lacking. The project team bases the proposed research program on the premise that fundamental understanding of cellulose-solvent molecular interactions (nanoscale), coupled with knowledge of the dissolution mechanism of semicrystalline cellulosic (microscopic) particles, can lead to the rational selection and (macroscopic) optimization of solvent processing conditions for cellulosic biomass. To this end, the team aims to (1) advance fundamental understanding of intermolecular interactions acting in select solvent systems that appear promising for dissolving cellulose, and express these interactions in terms of appropriate parameters, (2) identify and quantify the transport phenomena and kinetics governing the dissolution of solid cellulose, e.g., solvent penetration, transformation from crystalline to amorphous domains, specimen swelling, and polymer chain untangling, and (3) guide scale-up from the lab to industrial production by modeling the dissolution of polydisperse cellulose particulates (employing parameters determined in 1 and 2), exploring synergisms in mixtures of solvents and additives, and testing the dissolution of biomass specimens. In the above the team will target aqueous NaOH-based and ionic liquid solvent systems that exhibit a potential for process integration and are compatible with cellulose functionalization chemistry and biocatalysis. A main novelty of the proposed research resides in the team's concerted effort to rationally integrate cellulose dissolution information from the fundamental, (supra)molecular level to the practical, large-scale. This would have a transformative effect on what is mostly an empirical approach. Further novel aspects include (i) a unified approach for understanding molecular interactions in different solvent systems, including testing a recent hypothesis on the importance of hydrophobic effects which defies current wisdom; (ii) quantification of the dissolution mechanism, based on real-time monitoring of cellulose swelling and mass loss coupled with phenomenological modeling; (iii) characterization of cellulosic biomass structural evolution during dissolution; and (iv) experiments and population balance modeling on dissolution of polydisperse cellulose particulates. Each of these research topics will be new in the literature, and addressing all in tandem should prove powerful. Broader Impacts: In summary, this research will have a positive and timely impact on efforts directed toward the utilization of cellulosics as starting material for the synthesis of high value-added functional polymers and chemicals and also for biofuel production. The team's findings will be beneficial to nano/bio-applications where well-defined cellulose surfaces or nanoparticles are desired, and for the analytical characterization of cellulose and its derivatives; also to the solvent processing of difficult-to-dissolve liquid crystalline polymers and carbon nanotubes. Collaborations will be pursued with researchers in industry and in Europe. This project will integrate research and education by incorporating lectures and projects related to biomass, solvent selection, and dissolution modeling in the various courses that the PIs teach at both the undergraduate and graduate levels. Several students will contribute to this research, resulting in U.S.-based scientists who have both advanced technical training and sensitivity toward efficient resource utilization. The team will work with the AIChE student club to develop and offer outreach activities geared toward middle-school and 1st year college students.

智力价值：拟议的研究解决了对溶解纤维素这种丰富的可再生资源的综合方法的突出需求，作为将其加工成功能聚合物、特种化学品和生物燃料的重要步骤。虽然多种方法已被证明可用于结晶纤维素的活化，但仍在寻找能够有效溶解纤维素的溶剂。少数已知的能够溶解纤维素的溶剂是在严格且经常相互冲突的成分和温度条件下溶解的，并且缺乏基本的了解。该项目团队提出的研究计划的前提是对纤维素-溶剂分子相互作用（纳米级）的基本了解，加上对半结晶纤维素（微观）颗粒溶解机制的了解，可以导致合理的选择和（宏观）优化纤维素生物质的溶剂加工条件。 为此，该团队的目标是（1）增进对在有希望溶解纤维素的选定溶剂系统中作用的分子间相互作用的基本理解，并用适当的参数表达这些相互作用，（2）识别和量化传输现象和动力学控制固体纤维素的溶解，例如溶剂渗透、从结晶域到无定形域的转变、样品膨胀和聚合物链解开，以及（3）通过模拟多分散纤维素的溶解来指导从实验室到工业生产的放大颗粒物（采用 1 和 2 中确定的参数），探索溶剂和添加剂混合物的协同作用，并测试生物质样本的溶解。在上述内容中，该团队将瞄准基于 NaOH 的水性和离子液体溶剂系统，这些系统具有工艺集成的潜力，并且与纤维素功能化化学和生物催化兼容。该研究的主要新颖之处在于该团队共同努力，合理整合从基础（超）分子水平到实际大规模的纤维素溶出信息。这将对主要是经验主义的方法产生变革性的影响。其他新颖的方面包括（i）一种理解不同溶剂系统中分子相互作用的统一方法，包括测试最近关于疏水效应重要性的假设，该假设违背了当前的智慧； (ii) 基于纤维素膨胀和质量损失的实时监测以及现象学模型对溶解机制进行量化； (iii) 溶解过程中纤维素生物质结构演化的表征； (iv) 关于多分散纤维素颗粒溶解的实验和群体平衡模型。这些研究主题中的每一个都将是文献中的新主题，并且同时解决所有主题应该被证明是有效的。更广泛的影响：总而言之，这项研究将对利用纤维素作为合成高附加值功能聚合物和化学品以及生物燃料生产的起始材料的努力产生积极和及时的影响。该团队的研究结果将有利于需要明确纤维素表面或纳米粒子的纳米/生物应用，以及纤维素及其衍生物的分析表征；还适用于难溶解液晶聚合物和碳纳米管的溶剂加工。将与工业界和欧洲的研究人员进行合作。该项目将通过将与生物质、溶剂选择和溶解模型相关的讲座和项目纳入 PI 在本科生和研究生级别教授的各种课程中，将研究和教育结合起来。几名学生将为这项研究做出贡献，从而使美国的科学家既受过先进的技术培训，又对资源的高效利用敏感。该团队将与 AIChE 学生俱乐部合作，开发并提供针对中学生和一年级大学生的外展活动。