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Biocomposite

From Wikipedia, the free encyclopedia
Interior padding of a car's door, made of a hemp-polyethylene biocomposite

A biocomposite is a composite material formed by a resin matrix reinforced by natural fiber. Environmental concerns and the cost of synthetic fiber have led to its substitution with natural fibre, sourced from crops (cotton, flax or hemp), recycled wood, waste paper, crop processing byproducts, or regenerated cellulose fiber (rayon).

Interest in biocomposites is rapidly growing in terms of industrial applications and fundamental research due to its ecological and cost benefits. Biocomposites can be used alone or as a complement to standard composites, such as carbon fiber. Advocates of biocomposites state that these materials improve are environmentally superior, lighter in weight, safer to produce, and have a visual appeal similar to that of wood.[1][2][3][4]

Characteristics

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Wood fibers may be used to produce biocomposites.

As opposed to conventional composites, biocomposites utilize natural materials, which reduces their environmental impact. These materials are renewable, inexpensive, and in certain cases completely recyclable[5] or biodegradable. Natural fibers have a hollow structure, which translates to better thermal and sound insulation. Another advantage of natural fibers is their low density, which results in a higher specific tensile strength and stiffness than glass fibers. As such, biocomposites could be a viable ecological alternative to carbon fiber, fiberglass, and other such synthetic fiber composites in applications such as packaging, construction, automobiles, aerospace, military applications, electronics, consumer products and medical industry (prosthetic, bone plate, orthodontic archwire, total hip replacement, and composite screws and pins). However, biocomposites have limitations due to a lack of compatibility between synthetic resin and natural fibers.[6][7][8]

Classification

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Biocomposites are divided into wood and non-wood fiber composites, all of which contain cellulose and lignin. Wood fibers are classified as such if they contain a significant amount (almost 60%) of wood, and are further divided into softwood fibers (long and flexible) and hardwood fibers (shorter and stiffer), as well as recycled or non-recycled. Non-wood fibers are divided into straw, bast, leaf, seed or fruit, and grass fibers. The fibers most widely used in the industry are flax, jute, hemp, kenaf, sisal, and coir. Straw can be found in many parts of the world, and it is an example of a low-cost reinforcement for biocomposites. Matrices include polyethylene, polypropylene, and polyvinyl chloride.

Non-wood natural fibers are more attractive for the industry due to their physical and mechanical properties; these include their relative length, high cellulose content (which increases tensile strength), and higher cellulose crystallinity. The comparative disadvantages of wood fibers include the presence of hydroxy groups that can attract water molecules, causing the fibers to swell. This in turn results in voids between the fibers and matrix, which has negative effects on the composite's mechanical properties and dimensional stability.

Jute fibers are one of the most widely used in the industry.

Green composites

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Green composites are classified as biocomposites combining natural fibers with biodegradable matrices. They can be easily disposed of without harming the environment. Because of their durability, green composites are mainly used to increase the life cycle of products with short lives.

Hybrid composites

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A hybrid biocomposite uses different types of fibers, synthetic or natural, with a single matrix. Its functionality depends directly on the balance between the positive and negative traits of each individual material used, though the different types of fibers can account for each other's shortcomings. The properties of this biocomposite depend directly on those of the fibers, such as their content, length, arrangement, and bonding to the matrix. In particular, the strength of the hybrid composite depends on the failure strain of the individual fibers.

Classification of biocomposites
Biocomposites/biofibers
Type Non-wood natural fibers Wood fibers
Subtype Straw Bast Leaf Seed/fruit Grass Non-recycled Recycled
Examples Rice, wheat, corn straws Kenaf, flax, jute, hemp Henequen, sisal, penneaple leaf fiber Cotton, coir, coconut Bamboo, bamboo fiber, switch grass, elephant grass Soft, hard Newspaper, magazine

Processing

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Biocomposite materials, based on thermoplastic matrices, being processed by compounding and extrusion

The production of biocomposites uses techniques already used to manufacture plastics or conventional composites, including:

Applications

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Flax

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For automotive interiors, Composites Evolution performed prototype testing for the Land Rover Defender and the Jaguar XF, with the Defender's flax linen composite 60% lighter than its production counterpart but just as rigid, and the XF's flax composite part 35% lighter.[9]

In sports equipment, Ergon Bikes produced a concept saddle that won first place among 439 entries in the Accessories category at the Eurobike 2012 trade show.[10] VE Paddles has produced a flax boat paddle blade,[11] and Flaxland Canoes has developed a canoe with a flax linen hull.[12] Magine Snowboards has developed a snowboard that incorporates flax linen in its construction,[13] and Samsara Surfboards has produced a flax linen surfboard.[14] Idris Ski's Lynx skis won an ISPO Award in 2013 for their use of flax.[15]

Flax linen composites also work for applications for which the look, feel, or sound of wood is desired, but without susceptibility to warping, including furniture and musical instruments. A team at Sheffield Hallam University designed a cabinet with entirely sustainable materials, including flax linen.[16] Blackbird Guitars has produced a ukulele made with flax linen that has won a number of design awards in the composites industry,[17][18][19][20] as well as a guitar.[21]

Hemp

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For consumer goods, Trifilon has developed a number of hemp fiber biocomposites to replace conventional plastics. Suitcases, chillboxes, phone cases and cosmetic packaging have been produced using hemp fibers.

See also

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  • Pykrete, a composite of wood pulp and ice

References

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  1. ↑ "Are natural fiber composites environmentally superior to glass fiber reinforced composites?" (PDF). Michigan State University. Michigan State University. Retrieved 29 August 2015.
  2. ↑ "They may be sustainable, but how good are flax and jute for the engineer?". Engineering Materials. Findlay Media. Retrieved 8 September 2015.
  3. ↑ "Bio-composites update: Beyond eco-branding". Composites World. Gardner Business Media, Inc. Retrieved 1 September 2015.
  4. ↑ "Biocomposites Guide". NetComposites. NetComposites Ltd. Archived from the original on February 13, 2016. Retrieved 2018-10-01.
  5. ↑ "Are natural fiber composites environmentally superior to glass fiber reinforced composites?" (PDF). Michigan State University. Michigan State University. Retrieved 29 August 2015.
  6. ↑ Refiadi, Gunawan; Syamsiar, Yusi; Judawisastra, Hermawan (2019-09-05). "The Tensile Strength of Petung Bamboo Fiber Reinforced Epoxy Composites: The Effects of Alkali Treatment, Composites Manufacturing, and Water Absorption". IOP Conference Series: Materials Science and Engineering. 547 012043. doi:10.1088/1757-899x/547/1/012043. ISSN 1757-899X. S2CID 202968116.
  7. ↑ Judawisastra, H; Sitohang, R D R; Rosadi, M S (2017-09-20). "Water absorption and tensile strength degradation of Petung bamboo (Dendrocalamus asper) fiber—reinforced polymeric composites". Materials Research Express. 4 (9): 094003. doi:10.1088/2053-1591/aa8a0d. ISSN 2053-1591. S2CID 139794141.
  8. ↑ Judawisastra, H; Sitohang, R D R; Marta, L; Mardiyati (July 2017). "Water absorption and its effect on the tensile properties of tapioca starch/polyvinyl alcohol bioplastics". IOP Conference Series: Materials Science and Engineering. 223 012066. doi:10.1088/1757-899X/223/1/012066. ISSN 1757-8981. S2CID 136228188.
  9. ↑ "Lightweight Stiff Door Module". Composites Evolution. Composites Evolution. Archived from the original on 9 September 2015. Retrieved 1 September 2015.
  10. ↑ "Ergon Bike Ergonomics flax saddle is acclaimed by the whole bike industry". Play Naturally Smart. Bcomp. Retrieved 9 September 2015.
  11. ↑ "Flax composite paddle by VE Paddles using Bcomp's flax composite". JEC Composites. The Center for Promotion of Composites. 2013-12-12. Retrieved 1 September 2015.
  12. ↑ "Composites Evolution Showcase Biotex Flax Canoe". NetComposites. NetComposites. Archived from the original on March 11, 2016. Retrieved 2018-10-01.
  13. ↑ "Biocomposite snowboard using Biotex flax fabric". JEC Composites. The Center for Promotion of Composite. June 2012. Retrieved 9 September 2015.
  14. ↑ "Samsara 'eco surfboard' features Biotex flax fibre". Materials Today. Elsevier. Retrieved 9 September 2015.
  15. ↑ "Idris Skis - Lynx - ISPO Award Winner 2013". ISPO. ISPO. Retrieved 10 September 2015.
  16. ↑ "Lightweight Stiff Door Module". Sheffield Hallam University. Sheffield Hallam University. Retrieved 1 September 2015.
  17. ↑ "Blackbird launches plant fiber-based composite musical instrument". Composites World. Gardner Business Media. Retrieved 3 July 2015.
  18. ↑ "Check Out the Competition: Visit the Awards Pavilion at The Composites And Advanced Material Expo (CAMX)". Composites World. Gardner Business Media. Retrieved 3 July 2015.
  19. ↑ "Highlights from JEC Americas". Composites World. Gardner Business Media. Retrieved 3 July 2015.
  20. ↑ "2014 IDSA IDEA Award - Bronze - Entertainment - Blackbird Clara Ukulele". Industrial Designers Society of America. 2014-06-20. Retrieved 8 July 2015.
  21. ↑ "And Now, the Linen Guitar". Oakland Magazine. Telegraph Media. Archived from the original on 22 July 2015. Retrieved 3 July 2015.

Bibliography

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