Development of a rheologically-based dispersion quality index for cellulose nanocrystals in non-polar and thermoplastic media

纤维素纳米晶(CNCs)是一种丰富的、可再生、可持续、可回收和可生物降解的纳米材料来源，可用于制备聚合物纳米复合材料。然而，目前该行业面临着一个关键问题：由于合成的NC是高度亲水的，因此它在非极性溶剂和热塑性聚合物基质中不能很好地分散。如果没有方法来表征和量化它们的分散程度，就很难评估将不同的方法引入和分配到非极性矩阵中的成功。NSERC最近的一个战略性项目于2015年初完成，该项目的重点是开发流变学方法来表征基于数控的聚合物纳米复合材料的性能。蒙大略省理工学院(EPM)的Carreau和Heuzey和拉瓦尔大学(UL)的Riedl与FP Innovation(FPI)的Wadood Hamad博士合作参加了会议。这种正在进行的合作导致了关于CNC在聚合物纳米复合材料制造中的潜力的非常有趣的结果，但也有助于确定仍未解答的关键基本问题。这项建议旨在将这项研究更进一步，特别是通过调查数控表面改性方法的效果，开发基于流变学的“分散质量指数”，基于Tavares(EPM)、van de Ven(McGill)和Riedl(UL)在表面处理方面的专业知识，以及Heuzey和Carreau(EPM)广泛的流变学背景。由于流变性能对微观结构的微小变化非常敏感，因此流变仪被认为是表征碳纳米管分散状态的一种高效、低成本的技术。因此，该项目的主要目标是通过将流变性与扫描和透射电子显微镜观察到的实际微观结构进行比较，建立相关关系，量化碳纳米管在非极性基质中的分散程度。这将使加拿大大学在新的科学和战略领域，即纳米技术和生物聚合物领域，成为国际领先者。

Cellulose nanocrystals (CNCs) represent an abundant, renewable, sustainable, recyclable and biodegradable source of nanomaterials that can be used in the fabrication of polymer nanocomposites. However the industry is currently faced with a key issue: as synthesized, CNC is highly hydrophilic, hence it does not disperse well in non-polar solvents and thermoplastic polymer matrices. Without methods to characterize and quantify their level of dispersion, it is difficult to evaluate the success of different approaches for introducing and distributing CNC into non-polar matrices. A recent strategic NSERC project focusing on the development of rheological methods to characterize the properties of CNC-based polymer nanocomposites was completed in early 2015. It involved Carreau and Heuzey of École Polytechnique de Montréal (EPM) and Riedl of Université Laval (UL), in collaboration with Dr Wadood Hamad from FPInnovations (FPI). This ongoing collaboration leads to very interesting results on the potential of CNC in the fabrication of polymer nanocomposites, but has also served to identify key fundamental questions that remain unanswered. This proposal aims to take this research a step further, specifically by developing a rheologically-based "dispersion quality index" through an investigation of the effect of CNC surface modification approaches, building on the expertise of Tavares (EPM), van de Ven (McGill) and Riedl (UL) for surface treatment, and on Heuzey and Carreau's (EPM) extensive rheological background. Because rheological properties are very sensitive to small changes in microstructure, it is believed that rheometry could be efficient, low-cost techniques to characterize the state of dispersion of CNCs. The main goal of this project is therefore to develop correlations quantifying the extent of dispersion of CNCs into non-polar matrices by comparing rheological properties with actual microstructures observed by scanning and transmission electronic microscopy. This will position Canadian Universities as international leaders in new scientific and strategic fields, namely nanotechnology and biopolymers.******