Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 2B2, Canada.
Biomacromolecules. 2013 Sep 9;14(9):3155-63. doi: 10.1021/bm400784j. Epub 2013 Aug 19.
Dispersion quality and polymer-filler interaction are important factors in determining the final properties of polymer nanocomposites. Surface energy of nanocrystalline cellulose (NCC) and some polymers (polypropylene, PP, and polylactic acid, PLA) was measured at room and high temperatures. NCC had higher polarity and surface energy than PP and PLA at room temperature but had a lower surface energy at higher temperatures. The effect of surface modification with alkenyl succinic anhydride (ASA) on NCC surface energy at room and high temperature was studied. Total surface energy of NCC was lowered after surface modification. Thermodynamic work of adhesion for PP/NCC and PLA/NCC was lowered by NCC surface modification. A thermodynamic analysis is proposed to estimate the dispersion energy, based on surface energy measurements at room and high temperatures. Also, a dispersion factor is defined to provide a quantitative indication of the dispersibility of nanoparticles in a polymer matrix under various conditions. The required dispersion energy was reduced by lowering the interfacial tension. On the other hand, it increased as the quality of NCC dispersion (i.e., the nanoparticle surface area) in the system was improved. Surface modification of NCC with ASA had a negative effect on the compatibility between NCC and PLA, whereas it had a positive influence on compatibility between PP and NCC.
分散质量和聚合物-填料相互作用是决定聚合物纳米复合材料最终性能的重要因素。在室温及高温下测量了纳米纤维素（NCC）和一些聚合物（聚丙烯，PP 和聚乳酸，PLA）的表面能。NCC 在室温下比 PP 和 PLA 具有更高的极性和表面能，但在高温下具有更低的表面能。研究了用烯基琥珀酸酐（ASA）对 NCC 表面能在室温及高温下的表面改性的影响。NCC 的表面改性降低了其总表面能。NCC 表面改性降低了 PP/NCC 和 PLA/NCC 的热力学粘附功。提出了一种基于室温及高温表面能测量的热力学分析方法，以估算分散能。此外，还定义了一个分散因子，以在各种条件下定量表示纳米颗粒在聚合物基体中的分散性。通过降低界面张力，所需的分散能减少。另一方面，随着系统中 NCC 分散质量（即纳米颗粒表面积）的提高，分散能增加。NCC 用 ASA 进行表面改性对 NCC 和 PLA 之间的相容性有负面影响，而对 PP 和 NCC 之间的相容性有积极影响。
