Characteristics of cellulose fibers from Opuntia ficus indica cladodes and its use as reinforcement for PET based composites

ABSTRACT

With the aim of valorizing the unexplored Moroccan resources, Opuntia ficus indica (OFI) cladodes were proposed as a renewable source for the production of cellulose. In this work, cellulose microfibers were extracted from OFI cladodes using one of the most suitable methods for the extraction of cellulose based on the alkaline delignification. The morphological (SEM), thermal (TGA/DTG), and structural (XRD, FTIR, and ¹³C NMR) analysis of the isolated cellulose has been identified. Afterward, the reinforcing capability of cellulose fibers was examined using polyethylene terephthalate (PET) as a matrix by combining extrusion and compression molding processes. The effects of fibers loading on physical properties of the composites, such as tensile strength and Young’s Modulus before and after water absorption, were studied. The stability of the optimal composite was also examined based on the dependence of rheological parameters (G’ and G”) with strain and time. Composites containing 15 wt% of fibers exhibited the best mechanical properties in dry and wet cases, reaching 88% increase from neat PET in Young’s modulus and 36% increase in the tensile strength. However, excellent structural stability of the optimal composite was found with a predominant elastic behavior resulting from the good interface adhesion between cellulose fibers and PET matrix. The present work showed new routes for the valorization of OFI cladodes in the development of composite materials.

摘要

为了使摩洛哥未开发的资源价值化，建议将仙人掌作为生产纤维素的可再生资源. 本研究以碱法脱木素为基础，采用一种最适合于纤维素提取的方法，从OFI枝叉中提取纤维素超细纤维. 对分离的纤维素进行了形态（SEM）、热分析（TGA/DTG）和结构（XRD、FTIR和¹³CNMR）分析。其次，以聚对苯二甲酸乙二醇酯（PET）为基体，采用挤出成型和模压成型相结合的方法研究了纤维素纤维的增强性能. 研究了纤维负载量对复合材料吸水前后拉伸强度、杨氏模量等物理性能的影响. 根据流变参数（G′和G′）与应变和时间的依赖关系，考察了最佳复合材料的稳定性. 纤维含量为15wt%的复合材料在干态和湿态下的力学性能最好，杨氏模量比纯PET提高88%，拉伸强度提高36%. 然而，由于纤维素纤维与PET基体之间具有良好的界面结合力，优化后的复合材料具有优异的结构稳定性和优异的弹性性能。本研究为复合材料的开发提供了新的途径.

KEYWORDS:

• Cellulose
• opuntia ficus indica
• polyethylene terephthalate
• composite
• extrusion

关键词:

• 纤维素
• 仙人掌
• 聚对苯二甲酸乙二酯
• 复合材料
• 挤出

Acknowledgments

This research was supported by a grant from the Moroccan National Center for Scientific and Technical Research (CNRST). Grateful acknowledgement to the Analysis and Characterization center (CAC) at Cady Ayyad University.