Materials World Network: Molecular Engineering of Polymers for Processing Performance and Properties

材料世界网络：聚合物分子工程的加工性能和特性

• 批准号: 0602196
• 负责人: Donald Baird
• 金额: $ 48万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0602196&HistoricalAwards=false
• 关键词: Materials; World; Network; Molecular; Engineering

Sparse long chain branching, LCB(side chains attached to the main polymer backbone), i.e., branching levels typically less than one branch per 1000 backbone carbon atoms, and arm molecular weights, Ma, significantly greater than the critical molecular weight (MW) for entanglements, Me, have been reported to have remarkable effects on the rheology and processing behavior of polyolefins. For example, what is believed to be one branch in every three chains on average can have similar effects on the rheology of a polyethylene(PE) as having multiple branches of various types(long and short), high molecular weight, and a broad molecular weight distribution. The goal of this research is to develop a quantitative theory for the rheological response and associated processing performance of a melt of known polymerization kinetics. In other words, it is desired to predict polymerization conditions and catalyst structure which will lead to the molecular architecture needed to produce the desired rheology, processing performance, and properties. Furthermore, it is desired to evaluate the use of LCB to render ultra-high MW resins melt processable opening the door for producing high performance materials with many applications(e.g. prosthetics, ballistics protection, coatings, etc.).In order to theoretically design the molecular architecture of polymer chains for generating the desired processing performance, a highly interdisciplinary effort will be required which incorporates experts in experimental and theoretical rheology, polymer processing, polymerization kinetics and catalysts, and polymer synthesis and characterization (this expertise cannot be found in any one location). Scientists from two U.S. universities (Virginia Tech and the University of Tennessee) with expertise in extensional and non-linear rheology, flow birefringence, polymer processing and polymer synthesis and characterization will join forces with scientists from English(7), Dutch(1) and Greek(1) universities. The research effort will capitalize on the Leeds-based Microscale Polymer Processing (MuPP) consortium with contributions from Leeds (molecular rheology, reaction kinetics), Durham and Imperial College-London (chemistry), Sheffield (chemistry and crystallization), Cambridge and Bradford (small-scale processing), and Oxford and Eindhoven (solid state). The group at Imperial College, London is joining this co-operative program with expertise in polymerization catalyst development for tailored molecular structure. Scientists at Leeds are the world leaders in the development of molecular theories for branched polymers. The general approach is to use model systems to establish a rheological standard by which to identify the structures present in commercially produced PEs (standard analytical techniques cannot provide the required information) and then develop correlations between polymerization kinetics, molecular architecture and processing performance.The basis for designing the branching topology of polyolefins and other resins for processing performance and establishing polymerization conditions for generating this range of topologies will be established which has not been done before for branched polymers. In addition, this program will feed into the developing fundamental research program on the dynamics of branched polymers. Improvements in the molecular theory for the melt rheology of branched polymers will also be an outcome of this cooperative research effort. This research will have practical implications as it will allow industry to optimize the molecular architecture for processing performance and properties theoretically and thereby shorten time-intensive experimental programs. Graduate students will learn first hand the latest developments in molecular rheology and its use in designing molecules for processing performance. Exchanges between groups will accelerate the learning of both the theory and experimental techniques used in this program. Carefully selected undergraduates from underrepresented groups will be brought into the program to enhance their interest in polymer science and engineering.

稀疏的长链分支，LCB（附着在主要聚合物骨架上的侧链），即，分支水平通常小于每个1000个骨链碳原子的分支小于一个分支，并且MA的手臂分子量明显大于关键分子量（MW），ME（ME）对晶状体的影响很棒。例如，被认为在每三个链中被认为是一个分支的链条可能对聚乙烯（PE）的流变具有相似的影响，就像具有多种类型（长和短），高分子量和宽分子量分布的多个分支。 这项研究的目的是开发一种定量理论，用于用于融化已知聚合动力学融化的流变响应和相关的处理性能。 换句话说，希望预测聚合条件和催化剂结构，这将导致产生所需的流变，加工性能和特性所需的分子结构。此外，希望评估LCB使超高的MW树脂融化融化可加工的可加工，以生产具有许多应用的高性能材料（例如，假体，弹道保护，保护，涂料等）。为了使理论上设计的是在理论上设计的，它需要在理论上设计出高度的处理能力，以构建高度的处理，以构建高度的处理，并构成了高度的特定努力，该融合的努力是在努力，并构成了努力，该过程是构建的，该过程是在努力，并构成了努力，并构建了精美的努力。理论流变学，聚合物加工，聚合动力学和催化剂以及聚合物的合成和表征（在任何一个位置都找不到该专业知识）。来自两所美国大学（弗吉尼亚理工大学和田纳西大学）的科学家在伸展和非线性流变学，流动双折射，聚合物加工和聚合物的合成以及特征方面具有专业知识，将与来自英语（7），荷兰（1）和希腊语（1）大学的科学家联合起来。研究工作将利用基于利兹的微观聚合物加工（MUPP）联盟，并由利兹（分子流变，反应动力学），达勒姆和帝国大学 - 洛登（化学），谢菲尔德（化学和结晶），剑桥和布拉德福德（小刻度处理）和contecte Fordh and eindhoven（cambridge and Conforting）（剑桥）和欧洲（Cambridge）（化学和结晶）（化学）（化学）（化学和结晶）（化学和结晶）的贡献。伦敦帝国学院的该小组正在加入该合作计划，并具有针对量身定制的分子结构的聚合催化剂开发方面的专业知识。 利兹的科学家是分子聚合物分子理论发展的世界领导者。一般方法是使用模型系统来建立一种流变标准，通过该标准来确定商业生产的PE中存在的结构（标准的分析技术无法提供所需的信息），然后在聚合动力学，分子体系结构和处理性能之间建立相关性。在分支聚合物之前完成。 此外，该计划将介入有关分支聚合物动态发展的发展基础研究计划。 分支聚合物熔体流变学的分子理论的改善也将是这项合作研究工作的结果。 这项研究将具有实际的影响，因为它将允许行业优化用于处理性能和属性的分子体系结构，从而缩短时间密集型的实验计划。研究生将对分子流变学的最新发展及其在设计分子进行处理性能方面的最新发展。组之间的交流将加速该计划中使用的理论和实验技术的学习。从代表性不足的群体中精心挑选的本科生将被带入该计划，以增强他们对聚合物科学和工程的兴趣。