SGER: A New Approach to Composition Separation in Crystalizable Copolymers

9812261哈里森本次SGER奖的拟议研究代表了一种加快共聚物结晶-溶解过程的新方法。为了提高成分相似的材料的分离速度，速度是必要的。升温洗脱分馏(TREF)目前用于根据相对结晶度分离可结晶的共聚物，并获得共聚物中的组成分布。在使用所谓的“单位催化剂”开发最新一类聚烯烃方面，TREF的结果是关键。然而，像其他成分分离技术一样，Tref速度很慢。这项拟议的研究以Tref为起点，确定控制此类系统中分离的基本参数。这项拟议研究的结果将是将结晶共聚物的Tref分析时间从几天减少到一小时。提高分离速度的一种方法是将Tref转变为真正的层析技术，在这种技术中，随着物质沿柱子移动，组分之间的分离增加。这一承诺以前从未尝试过，这是对常态的戏剧性背离。在分离过程中，将采用区域精制的方法对TREF进行区域精制，以引入色谱性。正如提案中所描述的那样，最终的形式既不是区域精炼，也不是TREF，但可能会将分析时间减少50倍。辅助方法可能有助于分离，也存在其他通往层析方法的途径。这些将根据需要进行评估。%如果成功，“区域树”法在可结晶聚合物中的组成分布可以成为与GPC的分子量分布或DSC的熔融结晶度评价一样的标准。考虑到快速成分分析可能对整个塑料行业产生的潜在影响，特别是聚烯烃领域，希望通过SGER赠款对这一拟议方法进行早期评估。***

9812261 Harrison The proposed research in this SGER Award represents a new approach to speeding up crystallization-dissolution processes in copolymers. Speed is necessary to increase the rate at which similar-composition materials can be separated. Temperature- Rising Elution Fractionation (TREF) is currently used to separate crystallizable copolymers based on relative crystallizabilities, and to obtain a distribution of compositions within the copolymer. Results from TREF were key in developing the latest class of polyolefins using so called `single-site catalysts'. However, like other composition separation techniques, TREF is slow. The proposed research uses TREF as a starting point to identify those fundamental parameters that control separation in such systems. An outcome of the proposed study would be to reduce TREF analysis times in crystallizable copolymers from days, to an hour. One approach to increasing separation speed is to turn TREF into a true chromatographic technique where separation between components increases as material moves along a column. This undertaking has never before been attempted and represents a dramatic departure from the norm. A zone refining type modification of TREF will be used to introduce chromatographic character into the separation process. The final form, as described in the proposal, is neither zone refining nor TREF but could potentially reduce analysis time by a factor of 50. Supplementary methods may aid in separation and other routes to the chromatographic approach also exist. These will be evaluated as required. %%% If successful, composition distribution in crystallizable polymers by `zone TREF' can become as standard as molecular weight distribution by GPC, or melting-crystallinity evaluation by DSC. Given the potential impact which rapid composition analysis could have on the plastics industry in general, and the polyolefin segment in particular, early evaluation of this proposed methodology through a SGER grant is desirable. ***