Manufacturing Methods of PLA Composites

• Published in: Polylactic Acid-Based Nanocellulose and Cellulose Composites Vol. 1; pp. 51 - 82
• Main Authors: Jang, Guang-Way Bill, Hsieh, Cheng-Han, Lai, Allen, Chan, Sagle
• Format: Book Chapter
• Language: English
• Published: United Kingdom CRC Press 2022; Taylor & Francis Group
• Edition: 1
• Subjects: Oxygen Transmission Rate; PEO Content; Cf Composite; Neat PLA; Improve Interfacial Adhesion; PLA Nanocomposites; Pet Matrix; Compression Molding; Mulch Film; Cellulose Nanomaterials; Bamboo Fibers; ESO; Cellulose Composites; PLA Fiber; Brewer's Spent Grain; MCC; NCF; Chitin Nanocrystal; Melt Compounding; MMT; PLA Matrix; Cellulose Materials; Twin Screw Extruder; Bionanocomposite Films; PLA Composite
• ISBN: 9780367749538; 0367749521; 9780367749521; 036774953X
• DOI: 10.1201/9781003160458-3

Polylactic acid/cellulose fiber (CF) composites are potentially compostable and recyclable. There has been an intensive investigation into the preparation technologies and properties of PLA cellulose composites in recent years. Current efforts are focused on overcoming the interfacial adhesion between hydrophobic PLA and hydrophilic cellulose materials. Approaches include chemical and physical modification of cellulose materials and choice of suitable and optimal composite preparation conditions to both preserve the integrity of the structure of cellulose materials and avoid degradation of the polymer. Improved performance in various properties, including barrier, mechanical and thermal properties, was achieved for biocomposites obtained by reinforcing PLA with a broad range of cellulosic materials, such as wood fibers and flour, bamboo fibers, microcellulose fibers, microcrystalline cellulose (MCC) fibers, nanocellulose (NC) fibers, nanocrystalline CFs and many others. However, in order to make the best use of the numerous renewable cellulosic resources for the fabrication of high-performance biocomposites and to contribute to achieving global carbon neutrality, it is still crucial to continuously perfecting manufacturing processes for both the preparation of fiber-reinforced PLA and modification of cellulose materials. There is growing interest in plant-based composite materials that are environmentally friendly and have high performance. For this emerging market, there is an urgent need for clear labeling and end-of-use management schemes for biodegradable and compostable products. The strategic use of biocomposites will have both social and environmental benefits. The involvement of all stakeholders is necessary to achieve a closed-loop sustainable cycle for renewable materials. Polylactic acid is typically prepared by ring-opening polymerization of lactide, usually referred to as polylactide, or prepared by polycondensation of lactic acid, also referred to as poly. Success in developing nanocomposites with significant improvement in mechanical strength and low enforcement content relies on the uniform dispersion of cellulosic fiber (CF) in polymer matrices. Substitution of hydroxyl groups and grafting techniques are often applied for tuning the surface polarity of CF. Methods for the modification of CFs can be divided into physical, chemical, and biological routes. Chemical approaches are most often used. Sulfonation introduces charge to a cellulose structure and thus enhances its dispersibility in a selected solvent. Many techniques have been developed for sulfonation of cellulose since 1800 and use the resulting cellulose materials as anticoagulants and flocculants. Etherification of cellulose renders the material with improved water solubility. Solution casting has been a preferable approach to avoid irreversible agglomeration during drying.