RUI: Crystallization of Biologically-Relevant Poly(ethylene oxide)-b-poly(epsilon-caprolactone) Copolymers During Film Preparation

RUI：薄膜制备过程中生物相关聚（环氧乙烷）-b-聚（ε-己内酯）共聚物的结晶

• 批准号: 1606532
• 负责人: Ryan Van Horn
• 金额: $ 22.65万
• 依托单位: Allegheny College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1606532&HistoricalAwards=false
• 关键词: RUI; Crystallization; Biologically; Relevant; Poly

NON-TECHNICAL ABSTRACTMaterials used in the biomedical industry find utility based on the relationship between their structure and the properties needed. Among polymer materials (plastics) the relevant properties often include strength, flexibility, the ability to break down in the body, etc. Two such polymer materials, PEO and PCL, already find a variety of uses in the biomedical field, e.g. in implant coatings and medication-delivery systems. The range of applications increases when these two materials are combined. To engineer a specific product, one must know how to develop specific structures in this combined material (PEO-PCL). This research aims to understand how these structures develop and how to control the variability of the resultant properties. By varying the temperature and characteristics of the solution from which these materials are processed, one is able to obtain desired properties including, but not limited to, strength, flexibility, and breakdown rate. Polymers are uniquely suited for a variety of applications because their properties may span a large range depending on their chemistry and structure. For example, plastics can be rigid and brittle or flexible and soft depending on their structure. Understanding the development of PEO-PCL structures should lead to an increase in possible uses for this inexpensive, widely prevalent, and robust material. Moreover, the results of this study could be applied to the study of the structures and properties of other biomedical, commodity, or sustainable plastics. A second, but no less important, goal of this work is to train students in the broad disciplines of polymer and materials sciences and prepare them for careers in technology-related areas.TECHNICAL ABSTRACTStructural characterization is a critical component in predicting or tailoring the macroscopic properties of a material. In diblock copolymers, the structure involves phase separation between the two components and possible crystallization of one or both of the components. Poly(ethylene oxide)-block-poly(caprolactone) (PEO-b-PCL) copolymers are unique in several ways. First, they are both crystallizable with similar transition temperatures. Second, they are both prevalent in the biomedical field since they are biocompatible and since PCL is biodegradable. Lastly, by combining hydrophilic PEO and hydrophobic PCL into a block copolymer, the material is amphiphilic allowing for transport of hydrophobic drugs into the body. It is all of these traits that make these materials attractive for use in implant coatings and drug delivery systems. For these applications, the ability to manipulate the strength, elasticity, and degradation rate, amongst other properties, is important. These properties depend on how the material phase-separates and crystallizes from solution. Since phase separation is driven by crystallization, the focus of this research is to understand the crystallization mechanism and then control the crystallinity of the material by changing processing conditions such as temperature, casting solvent, and molecular weight. Using FTIR and DSC analyses, the crystallization of PEO and PCL blocks in samples with similar weight fractions or largely different weight fractions, cast from different solvents and/or annealed at different isothermal temperatures, will be monitored. Because the transition temperatures are similar, thermodynamic and kinetic considerations can be manipulated more easily by changes in these parameters. The goal is to pinpoint how each condition influences the crystallization mechanism, the overall crystallinity, and subsequent properties of interest in the biomedical field.

非技术摘要生物医学工业中使用的材料基于它们的结构和所需性能之间的关系而发现实用性。 在聚合物材料（塑料）中，相关的性能通常包括强度、柔韧性、在体内分解的能力等。两种这样的聚合物材料，PEO和PCL，已经在生物医学领域找到了各种用途，例如在植入物涂层和药物输送系统中。 当这两种材料结合在一起时，应用范围会增加。要设计特定的产品，必须知道如何在这种组合材料（PEO-PCL）中开发特定的结构。 本研究旨在了解这些结构是如何发展的，以及如何控制所得性质的可变性。 通过改变处理这些材料的溶液的温度和特性，能够获得所需的性质，包括但不限于强度、柔韧性和分解速率。 聚合物独特地适合于各种应用，因为它们的性质可以根据它们的化学和结构而跨越很大的范围。 例如，塑料可以是刚性和脆性的，也可以是柔性和柔软的，这取决于它们的结构。 了解PEO-PCL结构的发展应该会增加这种廉价，广泛流行和坚固材料的可能用途。 此外，本研究的结果可应用于其他生物医学，商品或可持续塑料的结构和性能的研究。 第二，但同样重要的是，这项工作的目标是培养学生在聚合物和材料科学的广泛学科，并准备他们的职业生涯在技术相关areas.TECHNICAL ABSTRACTStructural表征是一个关键组成部分，在预测或剪裁材料的宏观性能。 在二嵌段共聚物中，结构涉及两种组分之间的相分离和一种或两种组分的可能结晶。 聚（环氧乙烷）-嵌段-聚（己内酯）（PEO-b-PCL）共聚物在几个方面是独特的。 首先，它们都是可结晶的，具有相似的转变温度。 其次，它们在生物医学领域都很普遍，因为它们是生物相容的，并且因为PCL是可生物降解的。 最后，通过将亲水性PEO和疏水性PCL组合成嵌段共聚物，该材料是两亲性的，允许将疏水性药物转运到体内。 正是所有这些特性使得这些材料在植入物涂层和药物递送系统中具有吸引力。 对于这些应用，操纵强度、弹性和降解速率以及其它性质的能力是重要的。 这些性质取决于材料如何从溶液中相分离和结晶。 由于相分离是由结晶驱动的，因此本研究的重点是了解结晶机理，然后通过改变温度、浇铸溶剂和分子量等工艺条件来控制材料的结晶度。 使用FTIR和DSC分析，将监测具有相似重量分数或很大程度上不同重量分数、从不同溶剂浇铸和/或在不同等温温度下退火的样品中的PEO和PCL嵌段的结晶。 因为转变温度是相似的，热力学和动力学的考虑可以更容易地操纵这些参数的变化。 目标是查明每种条件如何影响结晶机制，整体结晶度以及生物医学领域中感兴趣的后续性质。