Deakin Research Online This is the published version: Afrin, T., Tsuzuki, T. and Wang, X. 2010, Bamboo : a distinctive green fibre, in ICTA 2010 : Recent Developments and Challenges of Textile and Apparel Industry : Proceedings of the 1st International Conference on Textile and Apparel, Amin and Jahan Corporation, Dhaka, Bangladesh, pp. 14-19. Available from Deakin Research Online: http://hdl.handle.net/10536/DRO/DU:30025540 Every reasonable effort has been made to ensure that permission has been obtained for items included in Deakin Research Online. If you believe that your rights have been infringed by this repository, please contact drosupport@deakin.edu.au Copyright : 2010, Amin and Jahan Corporation

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Bamboo: a distinctive "green" fibre

T. AFRIN' , T. TSUlUKl, x_ WANG Centre fOf Malerial and Fibre Innovation, Dea~ in Un j~ersjty , Geelong, VIC 3217, Australia taf@deakin.edll.all

Abstract

Technical Artlcl,

This article reports the preliminary findings on the morphology , chemical structure, antimicrobial and UV-screening properties of bamboo fibres. Bamboo fibres provide a very promising alternative to other natural fibres by virtue of their distinctive characteristics such as eco-friendly farming, inherent antimicrobial , UV-protective and highly· breathable properties. However, these novel properties are moslly claimed by fibre manufacturers, with little scientific evidence_ Moreover, those properties may largely depend on the manufacturing process, which is not widely disclosed by the manufacturers, Common manufacturing processes may require the use of a large amount of chemicals which would not make the product truly eco-friendly. Therefore, there is a strong need for unbiased laboratory experiments being conducted in a rigorous manner to elucidate the origin of those unique properties of bamboo fibres and to develop new processing methods to effectively utilise the properties in the final products. This research is aimed to prove the unique characteristics of bamboo fibres scientifically and to develop an efficient manufacturing process, in order to establish the place of bamboo fibres as a novel green material.

Keywords : Bamboo fibres , UV shielding, Antimicrobial, Green, Breathability.

1.0 Introduction Bamboo was used to build the first airplane that has ever flown and facilitated the flying of humanity for sure. Ultimate in potential , strong, light and renewable bio mass, bamboo is well known for its remarkably fast growth rate (Abadie , 2009, Scurlock et aI. , 2000). It needs no pesticides and irrigation to grow and offers the quickest way to achieve carbon neutral effects since each acre of bamboo sequesters up to 40 tons of C02. Unlike trees, bamboo plant fabricates microscopic plant stones that put carbon in a nutshell of silica and sequester an additional half ton of C02 per acre (liese, 2009). There is a growing awareness of environmentally friendly and sustainable technology around the globe. Bamboo comes from the nature , goes back to the nature at the end of their service life , leaving no harmful effect to the environment and thus they are considered as "green" material according to an eco-friendly concept (Afrin et aI. , 2009, Poole et aI. , 2009).

Bamboo is a lignocellulosic fibre and considered as a natural nanocomposite where cellulose is imbedded in the matrix of lignin and hemicelluloses (Rao and Rao, 2005). Bamboo is well reputed for its multi functionality serving the daily need of over 1.5 billion of people for centuries (liese, 2009). For example, its uses in structural composi te materials (Das and Chakraborty, 2008, Jain et aI. , 1992) are well described, Bamboo's ability as a medicine has been recognised for ages in Ayurveda and Chinese medicine to treat asthma, coughs and kidney disease, venereal disease, cancer and to improve oral hygiene and a cure of prickly heal (lu et aI., 2005, Song et at. , 2006, Shan et at , 2008). Cultivation of bamboo is not restricted in Asia nowadays but has extended in Europe and even in the chilled weather of Ireland, solving the problem of floods and used as an energy crop at Europe (Ndzana and Otterpohl, 2009, Potters et aI. , 2009) , Bamboo is also said to have unique properties such as inherent antimicrobial, UV shielding and breathable properties without aid from pelrolderivalive chemicals. These 'green' properties of bamboo have started 10 attract consumers in the textile market.

At present most of bamboo fibres are produced by the viscose route_ Sodium hydroxide and carbon di-sulphide are often used in the wet spinning process. Manufacturers are also using a Lyocell production method where the solvent is N-methylmorpholine-Noxide (Yang et at. 2009). The use of the term 'green' is questionable if harmful viscose production methods are used in the process . Some manufacturing companies are claiming that they use mechanical treatment along with biological degumming to produce bamboo textile fibres, This process can be considered as "green" but the shiny, smooth and luxurious appearance of the fibres, which is normally difficult to obtain by using degumming methods, gives rise 10 some doubt about the process claimed by the companies. Moreover, the unique properties of bamboo fibres are often claimed without scientific base (Afrin et aI. , 2009) . This paper reports preliminary scientific investigation on the validity and origin of Ihese claimed properties and on the method to retain the properties during fibre processing in an eco-friendly manner. 2.0 Experimental 2.1 Materials Bamboo (Phyllostachys pubescens) plant samples were sourced from Earthcare Farm at Crystal Waters

Technical Article

Permacullure Village of Queensland, Australia. They were matured culms and already dried. The culms were cut firstly with a chain saw, then cui 10 small lengths with a hand saw and split with a steel splitter. No chemicals were used for cleaning bullhere could be some chain Oil on the few cuts thai were made with the chain saw. Commercial degummed bamboo fibres were sourced from a manufactunng company in China.

2.2 Investigations The morphology was studied by using a confocal microscope (laiea res SP5) and a scanning electron microscope (SEM) (Neoscope, JCM-5000). A Fourier transform infrared spectroscopy (FT-IR) instrument (Bruker, Vertex 70) was used along with the software OPUS 5.5 to identify the chemical bonds. X-ray diffraclometry using a Phillips PW1729 instrument was conducted to find the information about the crystal structures of bamboo. UV-Vis spectroscopy was performed using a Varian Cary 3 instrument. Antibacterial tests were carried out following an Agar plate diffusion test technique. For SEM imaging, gold was applied on the samples an Emitech sputter cooter.

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Fogure , .• , Cross section and b: longitudlOal sectioo of rew bamboo under SEM

3.0 Results and discussion 3.1 Morphology of bamboo The cross section and longitudinal section of the raw bamboo were analysed under SEM as shown in Figure 1. The cross section (Figure 1a) indicates a bee hive structure and the longitudinal section (Figure 1b) resembles a brick wall and each structural unit had a length of -40 IJm and width of -25 IJm.

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Under the confocal microscope, numerous micro gaps or grooves were noticed (Figure 2a). These gaps and grooves

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were more evident under SEM (Figure 2b). The structure of the grooves was like capillaries. They were irregular in length but nearly 2 IJm in width. These numerous micro gaps contribute to the breathability of bamboo fibres. Therefore. consumers may experience instant moisture evaporation while wearing bamboo clothing if these grooves can be retained during fibre production, which may not be possible if viscose methods or other chemical solvents are used to dissolve cellulose.

Figure 3: a: Bamboo fibre wiltlout any treatment and b: commercial bamboo libre under SEM

Bamboo single fibres are very small and less than 2 mm in length (Yueping et aI. , 2009). Figure 3a shows a typical SEM image of untreated bamboo fibres that were collected from the protruding fibres of the bamboo culms using tweezers. The quantitative analysis of the chemical constituents following the Chinese Standard (GB5889·86) found that the sample had 53% (approximately) of cellulose. The diameler was -15 IJm. Figure 3b is a SEM image of the commercial bamboo textile fibre. The surface appeared to be much smoother than that of the untreated bamboo fibres. which raises some doubt about the company's claim on using degumming methods instead of viscose methods.

3.2 Chemical structure of bamboo XRD spectra reveal the crystalline structures of bamboo fibres that are related to the fibre properties such as strength, elongation , modulus. density and dyeing. Raw bamboo normally has the cellulose I crystalline structure, similar to flax, collon and ramie. Hemicellulose and lignin exist in amorphous forms in bamboo (Yueping et aI. , 2009). Figure 4 shows the XRD spectrum of raw bamboo. A diffraction peak is evident around 200 that corresponds to the (002) lattice plane of cellulose I crystallites. The hemicelluloses and lignin in amorphous forms may contribute to the peak to some extent as a broad background. On the other hand, it is known that bamboo viscose belongs to the cellulose II structure that has diffraction peaks at the angle of 120, 200 and 220 (Yueping et aI., 2009).

Figure 5 compares the FT-IR spectra of raw bamboo and commercial degummed bamboo fibres with a 100% cellulose pulp sheet. The spectrum of the commercial degummed bamboo fibres is nearly identical to that of the 100'% cellulose pulp sheet. The spectrum of the raw bamboo sample has additional fine structures in the range between 1200 and 1800 cm-1 , indicative of the presence of organic mailers (mostly lignin) other than cellulose. It makes raw bamboo different from other cellulose or lignocelluloses fibres such as callan. It also suggests that degummed bamboo may lack certain properties that derive from lignin in the raw bamboo.

3.4 UV shielding property of bamboo fibres UV-Vis spectroscopy revealed that extractions of bamboo absorb UV-lighl. in particular. UVB rays (Figure 6). Lignin extractions were carried out using four different solvents in order to identify the origin of the UV shielding ability of bamboo. In the first sample, the extraclion is done in water by boiling raw bamboo pieces in deionised water for 3 hours with a Material! Liquor (MIL) ratio of 1:30. In the second sample. bamboo pieces were immersed in ethanol for 24 hours at room temperature with an MIL ratio of 1:30. In the third sample , lignin components were extracted in an ethanol: water mixture with a volume ratio of 4:1 , as it has been reported by Bjorkman (Bjorkman, 1954) that lignin can be extracted only when the polar solvent like ethanol is mixed with a little amount of water in it. These samples were well diluted into the corresponding solvent in order to obtain clear transparent samples for UV-Vis absorbance measurements in transmission mode.

Techmcal Article

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For the fourth sample (Figure 6b), the lignin was extracted from a bamboo powder in aqueous diaoxane solution with a diaoxane: water volume ratio of 9:1, for 72 hours at room temperature with an Mil ratio of 1:30. The spectrum appeared quite similar to that of the other three extractions (Figure 6a), However, the peak at 230 nm is sharper and had a tiny peak around the 210 nm region. These preliminary spectra confirm that the UV shielding nature of bamboo is due to the lignin content of bamboo. Figure 6a suggests thai it was possible to partially extract lignin in water or ethanol. The results raise the issue that the conventional degumming methods, where starch or gummy material (lignin) is removed, may not be suitable for producing bamboo fibres with UV absorption properties, as suggested by FT-IR spectroscopy (Figure 5). An effective manufacturing process is needed to retain this unique property in the end product.

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Figure 6: a: UV absorbance or bamboo extractions in different solvents and b: UV absorbance of bamboo lignin.

3.5 Antimicrobial behaviour of bamboo Antibacterial tests were carried out on the raw bamboo. It has been observed that bamboo samples were attacked by fungi. The fungi appeared to be present on the surface of the raw bamboo.

Samples were first cleaned and then made smooth by a knife until there was visually no presence of fungi. All of the samples were prepared into the dimension of 50 mm x 12 mm. One group of the samples were autoclaved at 2100 C for 20 minutes. Another group of the samples were not autoclaved but were air-dried in the laboratory overnight. They were placed in soya agar plates (supplied from Oxoids) and tested against Escherichia coli (E. coli) .. After 18 hours of incubation at 370C, the plates were collected from the oven and placed on the fight box to identify the zone of inhibition.

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Figure 7: Anllmiaoblill ilctlvity test of bamboo (Ager plate diffusion tasl); Figur8 8. Bamboo fungi cullur8 the VIeW from \he bottom 01 the plait,

Figure 7 shows the antibacterial activity of a non autoclaved fresh bamboo piece. It is evident that no bacteria grew under the bamboo sample and that there was a dear zone of inhibition around the edge of the sample. Autoclaved samples showed identical results. This suggests that raw bamboo has an antibacterial property. The significantly narrow inhibition zone around the bamboo pieces indicates that the antibacterial substances in bamboo may be water-insoluble. It was thought that the fungi may exist not only on the surface of raw bamboo but also inside of the samples as endophytes. It was further found that the fungi did survive in the autoclave al 2100 C for 20 min. Therefore, it is speculated that the fungi may have some role in the antibacterial properties of raw bamboo, in a similar way as penicillin fungi. It also appeared that several types of fungi co-exist in the raw bamboo. Currently the isolation and purification of the fungi are being carried out to elucidate the antibacterial properties of the fungi (Figure 8).

4.0 Conclusions This paper reports the preliminary results on the morphology, chemical structure, antimicrobial and UV·screening properties of bamboo fibres. It was revealed that raw bamboo has natural antibacterial and UV screening properties as well as possible moisture absorption by micro pores in the structure. II is suggested that the antibacterial and UV screening properties stem from substances in lignin. However, FT·IR revealed that the degumming process during textile fibre production may remove most of the lignin, which may lead to the loss of those unique properties of bamboo. The possibility of bamboo fungi 's antibacterial function is raised, though their efficiency is yet to be validated. A novel processing technique to produce bamboo textile fibres that retain those unique properties of raw bamboo is currently being investigated.

Acknowledgements The authors would like to thank Dr. Rupinder Kanwar at the Centre for Biotechnology and Interdisciplinary Sciences (Bio Deakin), Deakin University, for her kind help in confocal imaging.

References ABADIE, M. (2009) Human Flying and Bamboo Fiber, from the Aviation Pioneer to Contemporary Design. IN LUCAS, S. & LIESE, W. (Eds.) 8th World Bamboo Congress. Bangkok, Thailand. Wor1d Bamboo Organization. AFRIN , T., TSUZUKI , T. & WANG, X. (2009) Bamboo fibres and their unique properties. IN WILSON, C. M. & LAING, R. M. (Eds.) Combined (NZ and Aus) Conference of The Textile Institute. Dunedin, NZ. BJORKMAN, A. (1954) Isolation of lignin from finely divided wood with neutral solvents. Nature, 174, 1057·1058. DAS, M. & CHAKRABORTY, D. (2008) Evaluation of Improvement of Physical and Mechanical Properties of Bamboo Fibers Due to Alkali Treatment. Journal of Applied Polymer Science, 107, 522·527. JAIN, S., KUMAR, R. & JINDAL, U. C. (1992) Mechanical behavior of bamboo and bamboo composites. Journal of Material Science, 27, 4598-4604. LIESE, W. (2009) Bamboo as Carbon-Sink - Fact or Fiction? IN LUCAS, S. & LIESE, W (Eds.) 8th World Bamboo Congress. Bangkok, Thailand , World Bamboo Organization . LU, B., WU, X., TIE , x. , ZHANG, Y. & ZHANG, Y. (2005) Toxicology and salety of antioxidant of bamboo leaves. Part 1: Acute and subchrooic toxicity studies on antioxidant of bamboo leaves. Food and ChemICal Toxicology, 43, 783· 792.

Technical Article

NOZANA, J. E. & OTTERPOHL, R. (2009) Contribution to Flood Management in European Cities through Bamboo Plantations. IN LUCAS, S. & LIESE, W. (Eds.) 8th world bamboo congress. Bangkok, Thailand, World bamboo organization. POOLE, A. J. , CHURCH, J. S. & HUSON, M. G. (2009) Environmentally sustainable fibres from regenerated protein. Bio Macromolecule, 10, 1-8. POTTERS, G .. BREMS. A., VALCKE, R.. DEWIL, R., O'HAESE, L., SAMSON, R. & GIELIS. J. (2009) Energy Crops in Western Europe: is Bamboo an Acceptable Alternative? IN LUCAS, S. & LIESE, W. (Eds.) 8th world bamboo congress. Bangkok, Thailand, World bamboo organization. RAO, K. M. M. & RAO, K. M. (2005) Extraction and tensile properties of natural fibers: Vakka. date and bamboo. Composite Structures, 77, 288-295. SCURLOCK, J. M. 0 ., DAYTONB, D. C. & HAMESB, B. (2000) Bamboo: an overlooked biomass resource? Biomass and Bioenergy, 19, 229·244. SHAN, B., CAl , Y., BROOKS, J. D. & CORKE, H. (2008) Antibacterial properties of Polygonum cuspidatum roots and their major bioactive constituents. Food Chemistry, 109, 530-537 . SONG, J. , KIM, S. , CHANG, K., HAN, S., VI , H. & JEON, J. (2006) In vitro inhibitory effects of Polygonum cuspidatum on bacterial viability and virulence factors of Streptococcus mutans and Streptococcus sobrinus. Archives of Oral Biology, 51 . 1 t 31-1140. YANG, G. S. , ZHANG, Y. P., SHAO, H. L. & HU, X. C. (2009) A comparative study of bamboo Lyocell fiber and other regenerated cellulose fibers. Walter De Gruyter & Co. YUEPING, W., GE, W., HAITAO, C., GENLlN, T., ZHENG, L. , QUNFENG, X .. XIANGQI, Z. , XIAOJUN, H. & XUSHAN, G. (2009) Structures of Bamboo Fiber for Textiles. Textile Research Journal online, 1-10.

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