Reinforcement of Polyester with Renewable Ramie Fibers

• Published in: Materials research (São Carlos, São Paulo, Brazil) São Paulo, Brazil), 2017-01, Vol.20 (suppl 2), p.51-59
• Main Authors: Simonassi, Noan Tonini, Pereira, Artur Camposo, Monteiro, Sergio Neves, Margem, Frederico Muylaert, Rodríguez, Rubén Jesus Sánchez, Deus, Janine Feitosa de, Vieira, Carlos Mauricio Fontes, Drelich, Jaroslaw
• Format: Article
• Language: English
• Subjects: Biofibers; Crack propagation; Energy measurement; ENGINEERING, CHEMICAL; Fiber composites; Fiber-matrix adhesion; Fibers; Flexural Properties; Fracture; Fracture mechanics; Impact Strength; Impact tests; Lignocellulose; MATERIALS SCIENCE, MULTIDISCIPLINARY; Mechanical properties; METALLURGY & METALLURGICAL ENGINEERING; Polyester; Polyester resins; Polyesters; Ramie fiber; Thermal Molding; Toughness
• ISSN: 1516-1439; 1980-5373; 1980-5373
• DOI: 10.1590/1980-5373-mr-2016-1046

Ramie (Boehmeria nivea) fiber is one of several lignocellulosic fibers with superior strength, but the least investigated, particularly as reinforcement in strong, tough polymeric composites. This paper presents mechanical properties for polyester reinforced with aligned ramie fibers up to 30% by volume. It was found that adding 30 vol% of ramie fibers increases the flexural strength of polyester about three times (212 ± 12 MPa vs. 63 ± 7 MPa) and tensile strength by a factor of two (89 ± 9 MPa vs. 53 ± 3 MPa). Polyester-ramie fiber composites also displayed a significant improvement in toughness. The impact energy values, as measured by Charpy and Izod impact tests, increased nearly two orders of magnitude for 30 vol% ramie fiber composite as compared to neat polyester. Additionally, fractographic studies revealed reasonable wetting of fibers by the polyester resin, and FTIR analysis confirmed a hydrophilic nature of ramie fibers. In spite of weak adhesion between hydrophilic fibers and hydrophobic matrix, composites of improved strength and toughness were demonstrated in this study. Limited fiber-matrix adhesion was reflected in preferential longitudinal propagation of cracks along the fiber/polyester interfaces, indicating also that most of the fracture area is associated with the fiber surface.