Biofiber Surface Treatments

A surface treatment of biofibers is an important step in the processing of biocomposites. There are three main reasons for using surface treatments of biofibers before incorporating them in biopolymers. 

---

Starch is one of the most widely used biopolymer in biocomposites because of its low cost and versatility. A plasticizer like glycol is sometimes used to make it suitable for processing. It is also blended with other polymers like aliphatic polyesters to improve its physical and mechanical properties. Biocomposites based on starch matrices show improved properties, which are comparable to E-glass/epoxy composites. Tensile, flexural, impact, and creep properties of these biocomposites are significantly better than those of neat starch. Various biofiber surface treatments have been shown to improve the properties of starch-based biocomposites. 

Nechwatal et al. 2003). Testing procedures have also been reported assessing biofiber applications in thermoplastic material by examining surface treatments and interfacial bonding components (Zafeiropoulos et al. 2002). 

The hydrophilic nature of cellulose fibers often results in poor compatibiHty with hydrophobic polymer matrices. Therefore, it becomes necessary to modify the surface of natural fiber for better binding between fiber and matrix. Chemicals are commonly used for the modification of cellulosic materials but large amount of solvents are also usually involved. Surface modification of biofibers using bacterial cellulose (BC) is one of the best methods for greener surface treatment of biofibers. 

PLA is another thermoplastic biopolymer that has the potential to replace commodity polymers such as PET, PS, and PC in everyday applications as well as a matrix for biocomposites. The mechanical properties of PLA are similar or in most cases are superior to petrochemical polymers, such as PR PLA is also blended with other polymers to improve its properties, particularly its lower thermal stability. PLA-based biocomposites are the most comprehensively researched of all the biocomposites. These biocomposites also exhibit excellent mechanical properties. Surface treatments of biofibers have positive effects on the properties of these composites. 

---