SGER: A New Approach to Composition Separation in Crystalizable Copolymers

本次SGER奖提出的研究代表了一种加速共聚物结晶溶解过程的新方法。速度对于提高相似成分的材料的分离速度是必要的。温升洗脱分馏（TREF）目前用于根据相对结晶性分离可结晶共聚物，并获得共聚物内成分的分布。TREF的结果是开发使用所谓的“单位点催化剂”的最新类聚烯烃的关键。然而，像其他成分分离技术一样，TREF是缓慢的。拟议的研究使用TREF作为起点，以确定在这种系统中控制分离的那些基本参数。拟议研究的结果是将可结晶共聚物中的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转变为一种真正的色谱技术，其中组分之间的分离随着材料沿色谱柱移动而增加。这项工作以前从来没有尝试过，它代表着对常规的极大背离。对TREF进行区域精炼型改性，将色谱特性引入分离过程。最终的形式，如建议中所述，既不是区域精炼也不是TREF，但可能会将分析时间减少50倍。补充方法可以帮助分离，也存在色谱方法的其他途径。这些将根据需要进行评估。如果成功，通过“区域TREF”在可结晶聚合物中的成分分布可以与GPC的分子量分布或DSC的熔融结晶度评估一样标准。考虑到快速成分分析可能对整个塑料工业，特别是聚烯烃部分产生的潜在影响，通过SGER拨款对这一拟议方法进行早期评估是可取的。＊＊＊

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. ***