Structural Recovery and Physical Aging in Plasticizing Environments

发现异常体积恢复聚合物玻璃进行增塑剂跳跃通过玻璃化转变将探索使用三个新的实验类。 首先，将研究结构恢复期间的质量吸收动力学。其次，将进行增塑剂跳跃后的第一焓恢复实验，以确定在玻璃态结构的焓部分中是否也发现观察到的体积异常。 这将需要在PI的实验室中为Calvet量热计开发一种独特的压力单元。第三，非共振介电烧孔光谱（NSHB）技术将被开发，以建立如何动态异质性的增塑剂跳跃和T-跳跃创建的玻璃比较。 实验结果将被解释内的能量景观范式的玻璃形成材料。这项工作将提供第一个完整的数据集，构建全范围的宏观变量（体积，焓和浓度），并将它们与玻璃结构或物理老化演变过程中材料微观性质（NSHB）的测量相关联。最后，德克萨斯理工大学的NSHB能力的开发将是美国第一个这样的设备。研究生和博士后研究员将在PI的直接监督下进行拟议的研究。拟议的工作预计将提供优秀的培训，研究生和博士后助理在前沿研究。作为培训的一部分，研究生和博士后将参加并在国家或地区会议上展示他们的研究成果。除了为学生提供良好的培训外，该项目的成果将尽可能纳入PI教授的本科和研究生课程。由于该研究是跨学科的，包含高分子材料科学（玻璃成型材料的结构恢复和增塑）和量热法以及基础凝聚态物理学（非共振光谱烧孔）的多个方面，因此该工作为研究生提供了难得的教育机会学生和博士后。他们将被要求熟悉该计划的各个方面。此外，这项工作还涉及两个重要的仪器设计和建造任务（量热计和介电NSHB装置的压力容器），这对实验科学家的教育很重要。***

The discovery of anomalous volume recovery in polymer glasses subjected to plasticizer-jumps through the glass transition will be explored using three new classes of experiment. First, the kinetics of mass absorption during structural recovery will be investigated. Second, the first enthalpy recovery experiments after plasticizer-jumps will be performed to determine if the observed volume anomalies are also found in the enthalpy part of the glassy structure. This will require development of a unique pressure cell for the Calvet calorimeter in the laboratories of the PI. Third, a non-resonant dielectric hole burning spectroscopy (NSHB) technique will be developed to establish how dynamic heterogeneity of the plasticizer-jump and T-jump created glasses compares. The experimental results will be interpreted within the energy landscape paradigm for glass-forming materials. The work will provide the first complete set of data that constructs the full range of macroscopic variables (volume, enthalpy and concentration) and relates them to a measure of the microscopic nature of the material (NSHB) during the evolution of glassy structure or physical aging. Finally, the development of the NSHB capabilities at Texas Tech University will be the first such apparatus in the United States.%%%The graduate students and post-doctoral researcher will perform the proposed research under the direct supervision of the PI. The proposed work is expected to provide excellent training for the graduate student and post-doctoral associate in cutting edge research. As part of their training, the graduate student and post-doc will attend and present their research results at national or regional meetings. In addition to providing good training for students, the results of the project will be incorporated to the extent feasible in both undergraduate and graduate courses taught by the PI. Because the research is interdisciplinary, containing multiple aspects of polymer materials science (structural recovery and plasticization of glass forming materials) and calorimetry as well as fundamental condensed matter physics (non-resonant spectral hole burning) the work provides a rare educational opportunity for the graduate student and post-doc. They will be expected to be familiar with all aspects of the program. In addition, the work involves two significant instrument design and construction tasks (pressure vessel for calorimeter and dielectric NSHB apparatus) that are important in the education of experimental scientists. ***