Sustainable & Green Plastics Laboratory, Metallurgical & Materials Engineering Department, Faculty of Chemical and Metallurgical Engineering, Istanbul Technical University, Maslak, Istanbul 34469, Turkey.
Sustainable & Green Plastics Laboratory, Metallurgical & Materials Engineering Department, Faculty of Chemical and Metallurgical Engineering, Istanbul Technical University, Maslak, Istanbul 34469, Turkey; Metallurgical & Materials Engineering Department, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, Esenler, Istanbul 34220, Turkey.
Int J Biol Macromol. 2023 Dec 31;253(Pt 3):126851. doi: 10.1016/j.ijbiomac.2023.126851. Epub 2023 Sep 13.
Melt processing of cellulose nanocrystals (CNCs) reinforced nanocomposites is still a serious challenge due to the hydrophilic nature of CNCs and their severe agglomeration tendency within the polymer melt. In this study, chemical modification of CNC through grafting poly(glycidyl methacrylate) (PGMA) with various degrees was implemented. Wettability of the modified CNCs (mCNCs) were controlled and their structure was characterized through Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), optical microscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The nanocomposites of polybutylene adipate terephthalate (PBAT) with 3 wt% CNC and mCNC were prepared using an internal melt mixer. To differentiate the effects of CNC and PGMA molecules on the final properties of nanocomposites, PBAT/PGMA compounds were separately prepared. To confirm the chain characterization and molecular weight of the synthesized PGMAs, H NMR and gel permeation chromatography (GPC) analysis were conducted. Melt rheological analysis, dynamic mechanical analysis (DMA), DSC, and atomic force microscopy (AFM) were used to monitor the mCNC dispersion quality and the effect of PGMA modification in PBAT compounds. The results revealed that grafting CNC with longer PGMA considerably improved the CNCs' dispersion quality within PBAT. Such dispersion enhancement of long-chain mCNCs and interfacial interaction of PGMA and PBAT resulted in a noticeable increase in storage modulus and complex viscosity of the final nanocomposites.
由于纤维素纳米晶（CNC）的亲水性及其在聚合物熔体中的严重团聚倾向，其熔融加工仍然是一个严峻的挑战。在本研究中，通过接枝不同程度的聚（甲基丙烯酸缩水甘油酯）（PGMA）对 CNC 进行了化学改性。通过傅里叶变换红外光谱（FTIR）、X 射线光电子能谱（XPS）、光学显微镜、X 射线衍射（XRD）、热重分析（TGA）和差示扫描量热法（DSC）对改性 CNC（mCNC）的润湿性和结构进行了控制和表征。使用内部熔融混合机制备了聚对苯二甲酸丁二酸丁二醇酯（PBAT）与 3wt% CNC 和 mCNC 的纳米复合材料。为了区分 CNC 和 PGMA 分子对纳米复合材料最终性能的影响，分别制备了 PBAT/PGMA 化合物。为了确认合成 PGMA 的链结构和分子量，进行了 H NMR 和凝胶渗透色谱（GPC）分析。采用熔体流变分析、动态力学分析（DMA）、DSC 和原子力显微镜（AFM）来监测 mCNC 在 PBAT 化合物中的分散质量和 PGMA 改性的效果。结果表明，用较长的 PGMA 接枝 CNC 可显著改善 CNC 在 PBAT 中的分散质量。长链 mCNC 的这种分散增强以及 PGMA 和 PBAT 之间的界面相互作用，导致最终纳米复合材料的储能模量和复数黏度显著增加。
