DYNA
0012-7353
Universidad Nacional de Colombia
https://doi.org/10.15446/dyna.v85n206.70889

Recibido: 7 de marzo de 2018; Revision Received: 25 de mayo de 2018; Aceptado: 4 de agosto de 2018

Morphological and nanomechanical characterization of Guadua Angustifolia kunth fiber by means of SEM and AFM

Caracterización morfológica y nanomecánica de la fibra de Guadua Angustifolia kunth mediante SEM y AFM

M. Espitia-Nery, aD. Corredor-Pulido, aN. Rodríguez-Ramírez, aJ. Bustos, a

a Facultad de Ingeniería, Corporación Universitaria Minuto de Dios, Bogotá, Colombia. mespitia@uniminuto.edu.co, dery.corredor@uniminuto.edu.co, nrodrigue35@uniminuto.edu.co, jcalderonbu@uniminuto.edu.co Corporación Universitaria Minuto de Dios Facultad de Ingeniería Corporación Universitaria Minuto de Dios Bogotá Colombia

Abstract

Recent developments in engineering have promoted the use of reinforced composite materials from natural fibers, which provides an opportunity to investigate such materials using state-of the-art tools. Here we present a morphological and nanomechanical characterization of the parallel section of the axis of guadua Angustifolia kunth fibers (GAK) from Colombia, focusing on properties such as hardness (nanoindentation), roughness and topography. Our method was based on the application of scanning electron microscope (SEM) and atomic force microscope (AFM). AFM provided curves of force by displacement, as well as characteristics of dynamic nanoindentation systems and images. Their analysis revealed ridges and valleys on the surface of GAK fibers. The estimated surface roughness of 9.51 nm suggests an adequate value to provide superior adhesion between polymer and fiber. The same conclusion follows from our measurements of hardness, reduced modulus and nanoscale topography. Due to their excellent properties, we conclude that GAK fibers represent an ideal reinforcement material in polymer matrices.

Keywords:

fibers of Guadua Angustifolia kunth, morphology, nanoindentation, SEM, AFM.

Resumen

El desarrollo reciente en la ingeniería propone el uso de materiales compuestos reforzados a partir de fibras naturales, lo cual genera la iniciativa de estudiarlos mediante herramientas sofisticadas. En esta investigación se muestran los resultados de la caracterización morfológica y nanomecánica como dureza (nanoidentación), rugosidad y topografía de la sección paralela al eje axial de fibras de guadua Angustifolia kunth, con el fin de encontrar las propiedades mecánicas a nanoescala de las fibras. Para ello se emplearon los microscopios electrónico de barrido (SEM) y de fuerza atómica (AFM), con este último se obtuvieron curvas de fuerza vs desplazamiento, características de sistemas dinámicos de nanoindentación e imágenes, donde a partir de análisis se encontró que la guadua Angustifolia kunth (GAK) presenta crestas y ondulaciones en su superficie, las cuales le brindan una rugosidad adecuada otorgando adherencia entre el polímero y la fibra, además la dureza, el módulo reducido y la topografía a escala nanométrica, lo que permite concluir que las fibras de GAK presentan mejores propiedades para ser utilizadas como material de refuerzo en matrices poliméricas.

Palabras claves:

fibras de Guadua Angustifolia kunth, morfología, nanoindentación, SEM, AFM.

1. Introduction

Polymer matrix composites consist of a continuous phase (polymer matrix) and a dispersed phase (particles or fibers) [1,2]. Usually the dispersed phase consists of fibers. Most studies have shown that synthetic fibers such as graphite [3,4] glass [5,6], carbon [7, 8], and thermoplastic resins such as polyesters and polypropylenes [9,10] among others, can be used as reinforcement for composite materials through the incorporation of fibers, thereby improving their properties [11]. However, many studies have ignored the high energy requirements and negative impact on the environment associated with the production of those materials. While some fibers are widely used in industry due to their excellent properties, they may on the other hand generate health problems such as asbestosis [12]. In Colombia, a considerable volume of organic waste derived from the production of fique, guadua, coconut, rice husk, bagasse, husk and other husk fibers have contributed to increasing pollution levels [13,14]. Therefore, the incorporation of organic fibers as reinforcement in polymeric matrices would not only avoid the use of synthetic or artificial fibers, but also reduce the environmental impact generated by their disposal.

2. Materials and methods

For our study, fibers of guadua Angustifolia kunth were collected in El Peñón, Cundinamarca Department, Colombia. Fiber extraction was mechanically carried out, so that fiber diameter was under 1mm and lengths under 5mm. Surfaces of GAK fibers were then modified with 5% sodium hydroxide (NaOH) solution to remove impurities [36], continuously stirred for half an hour at room temperature, and finally washed with distilled water (neutral pH) to completely eliminate NaOH. Fibers were then left to dry for 12 hours at room temperature, and 24 hours at 60 ° C [37].

2.1. Scanning electronic microscopy (SEM)

Fibers were coated with gold to increase conductivity of samples and enable analysis by a Scanning Electron Microscope, JEOL brand, model JSM 6490-LV. ImageJ software was used for processing of digital images and measurement of average diameter and cross-sectional area of fibers.

2.2. Atomic force microscopy (AFM)

To investigate the mechanical behavior of natural fibers at low scale through instrumented indentation tests, we used the AFM brand ASYLUM RESEARCH, model MFP-3D-BI. Fibers were cut down to a length of 5mm, and appropriate points for nanoindentation were identified on their surface. This process consists in applying a force to the fiber with the tip of an indenter or cantilever to create indentation marks. The tip is pressed continuously against the fiber for about 2 seconds, and the resulting displacement is measured. Data on force vs. displacement, and on indenter geometry, were used to calculate hardness (H), reduced modulus (Er), rupture modulus (H/Er), resistance to plastic deformation (H³/Er²) and elastic module, after the method proposed in 1992 by Oliver and Pharr. In addition, fibers were swept before and after the indentation at low force using the same indentation tip, thereby generating a topographic record on nanometric scale. The obtained nanoscale topographic images of fiber and indentation traces enabled quantification of the stacking of ductile material around the indenter. For the nanoindentation test, an AC 160 TS Olympus indenter was selected based on the principle that the indenter tip must have an elastic modulus equal to or greater than the sample in order to generate a deformation. Finally, water left over from the NaOH treatment was slowly neutralization (until neutral pH) by diluted acetic acid (vinegar) and disposed by a hazardous waste management company with a valid environmental license.

3. Results and discussion

3.1. Morphological characterization

Fig. 1 shows the cross section of a GAK fiber from the interior of the cluster and treated with 5% NaOH. The fiber has an irregular and elongated shape, while its transversal area is composed of irregularly shaped microfibers. Average value was 13301.806 μm2.

Transversal section of GAK fiber.

Figure 1: Transversal section of GAK fiber.

Source: Authors.

Fig. 2 shows a comparison between two GAK fibers with and without the 5% sodium hydroxide treatment. The untreated fiber presents irregularities due to the presence of lignin and hemicellulose [38], while the treated fiber exhibits no imperfections, and instead consists of visible microfibrils (observable in the cross-section). Treatment exposes microfibers aligned in the axial direction, which is relevant for applications to composite materials by providing stronger adherence between the polymer matrix and natural fibers.

Longitudinal section of GAK fiber, with and without 5% NaOH treatment.

Figure 2: Longitudinal section of GAK fiber, with and without 5% NaOH treatment.

Source: Authors.

3.2. GAK topography

Prior to indentation, we recorded the longitudinal topography of a section of GAK fiber measuring 5um x 5um. Fig. 3 shows that the GAK fiber displays an irregular structure on most of its surface.

Longitudinal section of GAK fiber before indentation. AFM altitude image.

Figure 3: Longitudinal section of GAK fiber before indentation. AFM altitude image.

Source: Authors.

Fig. 4 is a 3D section along the longitudinal axis of the GAK fiber, revealing surfaces without defined shape that protrude between 0.888μm-0.612μm relative to the general surface. It exhibits superior roughness (Ra) to the areca palm [39], but inferior to flax [40]. This level of roughness may facilitate adhesion between polymer matrices and GAK fibers, confirming our SEM findings.

3D morphology of the longitudinal surface of GAK fiber.

Figure 4: 3D morphology of the longitudinal surface of GAK fiber.

Source: Authors.

3.3. Nanoindentation

Figs. 5 and 6 show a longitudinal section of GAK fibers before and after nanoindentation. In Fig. 5, cellulose microfibers are observed in lignin within the hemicellulose matrix [34] and aligned with the main axis of the GAK fiber. Due to their orientation, microfibers confer guadua superior resistance to tension along the main axis of the fiber. In addition, the distribution of microfibers confirms that guadua is an orthotropic material [41]. Moreover, Fig. 6 shows 10 nanoimprints with different indentation depths, as shown in Table 2. Nanoimprints 2, 3 and 4 cannot be clearly seen in Fig. 6 since the nanoindentation zone exhibits elastic behavior, recovering by 98.7%, 96.70 and 96.13% respectively after removal of the indentation load, therefore presenting no residual deformation. In contrast, nanoimprints 1, 5-10 presented only minor and non-identifiable recovery.

Longitudinal section of GAK fiber prior to indentation. AFM amplitude image.

Figure 5: Longitudinal section of GAK fiber prior to indentation. AFM amplitude image.

Source: Authors.

Longitudinal section of GAK fiber after indentation. AFM amplitude image.

Figure 6: Longitudinal section of GAK fiber after indentation. AFM amplitude image.

Source: Authors.

Fig. 7 shows the loading and unloading curve of nanoimprint 1. The curve is similar for indentations on other nanoimprints, which is most likely explained by the similar elastic properties of GAK fibers in most of their surface.

Full loading-unloading cycle of nanoimprint 1.

Figure 7: Full loading-unloading cycle of nanoimprint 1.

Source: Authors.

Following the analysis of curves and the method proposed by Oliver and Pharr, Table 1 presents measures of hardness, reduced modulus, modulus of rupture and resistance to plastic deformation for each of the 10 nanoimprints. Hardness ranges between 10.27 and 13.48MPa, demonstrating the homogeneity of the longitudinal section. However, the relative divergence of hardness in nanoimprint 2 and 9 could be the outcome of specific load distributions. The average hardness of GAK fibers is 11.75MPa, below the reported values for other fibers such as flax, hemp, cotton and pineapple [42]. Reduced modulus ranges between 11.65 and 14.27 MPa, which are low values compared to sisal fibers, and result from the disposition or crystallinity of cellulose microfibers [41]. Average breaking modulus and resistance to plastic deformation were respectively estimated in 0.91 and 9.68MPa.

Table 1: Mechanical properties at the nanoscale of GAK fibers.

Source: Authors.

The behavior after a full cycle of loading and unloading for the 10 nanoimprints is shown in Fig. 8. Loading and unloading cycles originating from the indentation in the longitudinal section of the fiber exhibit almost no variability. Variation in curves is possibly caused by the distribution of forces during the application and removal of the load. In addition, ridges and ripples may affect the area where load is applied, as they may reduce contact area and therefore also the reaction force.

Loading-unloading curves of the 10 nanoimprints on GAK fibers.

Figure 8: Loading-unloading curves of the 10 nanoimprints on GAK fibers.

Source: Authors.

Table 2 presents values of maximum indentation deformation (hmax) obtained from the load vs. displacement curves (Fig. 8), as well as residual depth values (h) for each nanoimprint and the percentage of elastic recovery.

Table 2: Elastic properties of GAK fibers.

Source: Authors.

Residual deformation of nanoimprints is variable; however, nanoimprints 2, 3 and 4 show the highest residual difference, with values of 17.49, 42.31 and 52.15 nm. This confirms that they exhibit the highest values of elastic recovery (Table 2), as shown in Fig. 6 where they do not exhibit an indentation mark. On the other hand, the nanoimprints with the most visible marks in indentation (Fig. 6) show the highest values of residual deformation.

Fig. 9 shows the residual deformation on nanoimprint 2 after application of load. Residual depth on all nanoimprints is obtained from the topographic profile, with a value of 17.49nm in nanoimprint 2, which displays a minimum amount of stacking on the sides but no sinking nonetheless. This is due to the characteristics of plasticity and elasticity of the material.

Topographic profile of residual deformation in nanoimprint 2.

Figure 9: Topographic profile of residual deformation in nanoimprint 2.

Source: Authors.

Application of the maximum indentation load (29,91uN) on all nanoimprints resulted in maximum deformations (hmax) of 1290 ± 60um of the GAK fibers (Table 2). When the load is removed, fibers recover from deformation by an amount ranging between 1160 and 1320 nm (Fig. 10). This demonstrates the elastic recovery of GAK fibers, which averaged 94.54%. Recovery occurs since the atoms in the fiber are not permanently displaced, with the force applied in the indentation being stored as a distortion of fiber interatomic bonds [43].

Elastic recovery of GAK fibers after nanoindentation essay.

Figure 10: Elastic recovery of GAK fibers after nanoindentation essay.

Source: Authors.

Table 3 shows the summary of average mechanical properties of GAK fibers resulting from instrumented nanoindentation.

Table 3: Elastic properties of GAK fibers.

Source: Authors.

4. Conclusions

Due to their characteristics, fibers of Angustifolia kunth guadua are a viable alternative to reinforcement of composite materials. Our sampled fibers had an average cross-sectional area of 13301.806 μm2 as measured by SEM. GAK fibers also exhibited ridges and undulations resulting in considerable levels of rugosity, which constitutes a key feature by enabling stronger adhesion to polymer matrices.

Furthermore, AFM characterization demonstrated that the cross section of GAK fibers is formed by microfibrils in the longitudinal direction, providing excellent resistance to tension in that direction. In addition, most of the nanoimprints on the GAK fibers presented minimal stacking, and no sinking. The findings validate the view that GAK fibers are ideally suited to be used as reinforcement in compound materials. Similarly, characterization of the GAK fiber longitudinal section revealed irregularities, which can nonetheless be removed through application of 5% NaOH.

Mechanical characterization at nanometric scale revealed that Angustifolia kunth guadua fibers had an average hardness of 11,75MPa, a reduced modulus of 12.97MPa and break of and 0.91 respectively. Characterization also showed that GAK fibers exhibited a plastic deformation resistance of 9.68MPa and an elastic recovery of 94.54%.

Acknowledgements

Acknowledgements

We thank the Microscopy Center, Universidad de los Andes; the Faculty of Engineering and Basic Sciences, Department of Electronic Engineering; Solid State, Micro and Nanostructures Unit; and the NBIC Research Cluster at the Universidad Central.

References

  1. [1] Hidalgo, M.A., Muños, M.F. and Quintana, K.J. Desempeño mecánico del compuesto aluminio reforzado con agro fibras contínuas de fique. Revista Latinoamericana de Metalurgia y Materiales, 31(2), pp. 187-194, 2011. 🠔
  2. [2] Ru-Min, W., Shui Rong, Z. and Ya Ping, Z. Polymer matrix composites and technology. Georgia: Woodhead Publishing, 1, pp. 1-28, 2011. 🠔
  3. [3] Baptista, R., Mendão, A., Rodrigues, F., Figueiredo, C. G., Guedes, M. and Marat, R. Effect of high graphite filler contents on the mechanical and tribological failure behavior of epoxy matrix composites. Theoretical and Applied Fracture Mechanics, 85, pp. 113-124, 2016. DOI: http://doi.org/10.1016/j.tafmec.2016.08.013 [URL] 🠔
  4. [4] Khalili, P., Tshai, K.Y. and Kong, I., Natural fiber reinforced expandable graphite filled composites: evaluation of the flame retardancy, thermal and mechanical performances. Composites: Part A, 100, pp. 194-205, 2017. DOI: 10.1016/j.compositesa.2017.05.015 [DOI] 🠔
  5. [5] Pedrazzoli, D. and Pegoretti, A., Expanded graphite nanoplatelets as coupling agents in glass fiber reinforced polypropylene composites. Composites: Part A , 66, pp. 25-34, 2014. DOI: 10.1016/j.compositesa.2014.06.016 [DOI] 🠔
  6. [6] Papageorgiou, D.G., Kinloch, I.A. and Young, R.J., Hybrid multifunctional graphene/glass-fibre polypropylene composites. Composites Science and Technology, 137, pp. 44-51, 2016. DOI: 10.1016/j.compscitech.2016.10.018 [DOI] 🠔
  7. [7] Kwan, K., Hye, L., Jeong, A., Dong, C., Kay, A. and Byung, K., Recycling and characterization of carbon fibers from carbon fiber reinforced epoxy matrix composites by a novel super-heated-steam method. Journal of Environmental Management, 203, pp. 872-879, 2017. DOI: 10.1016/j.jenvman.2017.05.015 [DOI] 🠔
  8. [8] Sharma, M., Rao, I. and Bijwe, J., Influence of orientation of long fibers in carbon fiber-polyetherimide composites on mechanical and tribological properties. Wear, 267, pp. 839-845, 2009. DOI: 10.1016/j.wear.2009.01.015 [DOI] 🠔
  9. [9] Serrano, R., Cobo, A., Prieto, M.I. and González, M., Analysis of fire resistance of concrete with polypropylene or steel fibers. Construction and Building Materials, 122, pp. 302-309, 2016. DOI: 10.1016/j.conbuildmat.2016.06.055 [DOI] 🠔
  10. [10] Kakooe, S., Md-Akil, H., Jamshidi, M. and Rouhi, J., The effects of polypropylene fibers on the properties of reinforced concrete structures. Construction and Building Materials , 27, pp. 73-77, 2012. DOI: 10.1016/j.conbuildmat.2011.08.015 [DOI] 🠔
  11. [11] Amine, M., Hegde, K., Rouissi, T., Kaur, S., Galves, R., Sorelli, L., Ben, R., Paiva, M. and Abokitse, K., Green synthesis of novel biocomposites from treated cellulosic fibers and recycled bio-plastic polylactic acid. Journal of Cleaner Production, 164, pp. 575-586, 2017. DOI: 10.1016/j.jclepro.2017.06.235 [DOI] 🠔
  12. [12] Ramos, J. and Cely, M., Exposición personal a asbestos en dos talleres de frenos para vehículos de flota pesada en la ciudad de Bogotá. Fundación Mapfre, [Online]. 2011. [date of reference: November 4th of 2017]. Available at: Available at: https://es.scribd.com/document/384252215/ASBESTO-EN-LOS-TALLERS-DE-VEHICULOS [URL] 🠔
  13. [13] Jaramillo, G. y Zapata, L.M., Aprovechamiento de los residuos sólidos orgánicos en Colombia, Esp. Tesis, Facultad de Ingeniería, Universidad de Antioquia, Medellín, Colombia, 2008. 🠔
  14. [14] Águila, I. y Sosa, M., Evaluación físico química de cenizas de cascarilla de arroz, bagazo de caña y hoja de maíz y su influencia en mezclas de mortero, como materiales puzolánicos. Revista de la Facultad de Ingeniería U.C.V [Online]. 23(4), 2008. [date of reference November 4th of 2017]. Available at: Available at: http://saber.ucv.ve/ojs/index.php/rev_fiucv/article/view/5078 [URL] 🠔
  15. [15] Bordoloi, S., Hussain, R., Garg, A., Sreedeep, S. and Zhou, W.-H., Infiltration characteristics of natural fiber reinforced soil. Transportation Geotechnics, 12, pp. 37-44, 2017. DOI: 10.1016/j.trgeo.2017.08.007 [DOI] 🠔
  16. [16] Steffens, F., Steffens, H. and Ribeiro, F., Applications of natural fibers on architecture. Procedia Engineering, 200, pp. 317-324, 2017. DOI: 10.1016/j.proeng.2017.07.045 [DOI] 🠔
  17. [17] Balakrishnan, P., John, M., Pothen, L., Sreekala, M. and Thomas, S., Natural fibre and polymer matrix composites and their applications in aerospace engineering. Advanced Composite Materials for Aerospace Engineering, pp. 365-383, 2016. DOI: 10.1016/B978-0-08-100037-3.00012-2 [DOI] 🠔
  18. [18] Ashik, K.P. and Sharma, R., A review on mechanical properties of natural fiber reinforced hybrid polymer composites. Journal of Minerals and Materials Characterization and Engineering, 3, pp. 420-426, 2015. DOI: 10.1016/j.matpr.2017.11.276 [DOI] 🠔
  19. [19] Rodríguez, L., Sarache, W. and Orrego, C., Compuestos de poliéster reforzados con fibra de plátano/banano (musa paradisiaca) modificada químicamente. Comparación con Fibra de Vidrio y Fique (Furcraea andina). Información tecnológica, 25(5), pp. 27-34, 2014. DOI: 10.4067/S0718-07642014000500005 [DOI] 🠔
  20. [20] Danso, H., Properties of coconut, oil palm and bagasse fibres: as potential building materials. Procedia Engineering , 200, pp. 1-9, 2017. DOI: 10.1016/j.proeng.2017.07.002 [DOI] 🠔
  21. [21] Wang, W. and Chouw, N., The behaviour of coconut fibre reinforced concrete (CFRC) under impact loading. Construction and Building Materials , 134, pp. 452-461, 2017. DOI: 10.1016/j.conbuildmat.2016.12.092 [DOI] 🠔
  22. [22] Mwaikambo, L., Review of the history, properties and application of plant fibres. African Journal of Science and Technology (AJST) [Online]. 7(2), 2006. [date of reference November 17th of 2017]. Available at: Available at: https://www.researchgate.net/publication/284760719_Review_of_the_history_properties_and_application_of_plant_fibres [URL] 🠔
  23. [23] Hidalgo, M., Muñoz, M. y Quintana, K., Análisis mecánico del compuesto polietileno aluminio reforzado con fibras cortas de fique en disposición bidimensional. Revista Latinoamericana de Metalurgia y Materiales [Online]. 32(1), 2012. [date of reference November 19th of 2017]. Available at: Available at: http://www.rlmm.org/ojs/index.php/rlmm/article/view/117 [URL] 🠔
  24. [24] Pietroniro, M. y Bloem, C., Ventajas del algodón frente al fique como refuerzo en compuestos poliméricos. Ciencia e Ingeniería [Online]. 36(1), 2015. [date of reference November 20th of 2017]. Available at: Available at: http://erevistas.saber.ula.ve/index.php/cienciaeingenieria/article/view/5495/0 [URL] 🠔
  25. [25] Karaduman, Y., Gokcan, D. and Onal, L., Effect of enzymatic pretreatment on the mechanical properties of jute fiber-reinforced polyester composites. Journal of Composite Materials, 47(10), pp. 1293-1302, 2012. DOI: 10.1177/0021998312446826 [DOI] 🠔
  26. [26] Bursi, N., Gualtieria, A.F., Pollastria, S. and Tibaldib, E., Assessment of asbestos body formation by high resolution FEG-SEM after exposure of Sprague-Dawley rats to chrysotile, crocidolite, orerionite. Journal of Hazardous Materials, 306, pp. 95-104, 2016. DOI: 10.1016/j.jhazmat.2015.11.050 [DOI] 🠔
  27. [27] Fang, C.-H., Jiang, Z.-H., Sun, Z.-J., Liu, H.-R., Zhang, X.-B., Zhang, R. and Hua Fei, B., An overview on bamboo culm flattening. Construction and Building Materials , 171, pp. 65-74, 2018. DOI: 10.1016/j.conbuildmat.2018.03.085 [DOI] 🠔
  28. [28] Kaminski, S., Lawrence, A. and Trujillo, D., Structural use of bamboo: Part 1: Introduction to bamboo. The Structural Engineer [Online]. 94(8), 2016. [date of reference November 20th of 2017]. Available at: Available at: https://www.researchgate.net/publication/305808084_Structural_use_of_bamboo_Part_1_Introduction_to_bamboo [URL] 🠔
  29. [29] Zakikhani, P., Zahari, R., Sultan, M. and Majid, D., Extraction and preparation of bamboo fibre-reinforced composites. Materials & Design, 63, pp. 820-828, 2014. DOI: 10.1016/j.matdes.2014.06.058 [DOI] 🠔
  30. [30] Valarezco, L.E., Obtención experimental de un material biocompuesto a base de una matriz polimérica y reforzada con fibras naturales de guadúa angustifolia proveniente del Ecuador, Pregrado. Tesis, Facultad de Ingeniería, Universidad Politécnica Salesiana, Cuenca, Ecuador, 2013. 🠔
  31. [31] Luna, P., Marriaga, J. and Mariño, A., Guadua angustifolia bamboo fibers as reinforcement of polymeric matrices: An exploratory study. Construction and Building Materials , 116, pp. 93-97, 2016. DOI: 10.1016/j.conbuildmat.2016.04.139 [DOI] 🠔
  32. [32] AL-Oqla, F.M. and Sapuan, S.M., Natural fiber reinforced polymer composites in industrial applications: feasibility of date palm fibers for sustainable automotive industry. Journal of Cleaner Production , 66, pp. 347-354, 2014. DOI: 10.1016/j.jclepro.2013.10.050 [DOI] 🠔
  33. [33] Salas, E., Actualidad y futuro de la arquitectura de bambú en Colombia, PhD. Tesis, Departamento de Construcciones Arquitectónicas, Universidad Politécnica de Cataluña, Barcelona, España, 2006. 🠔
  34. [34] Hao, H., Tam, L.-H., Lu, Y. and Lau, D., An atomistic study on the mechanical behavior of bamboo cell wall constituents. Composites Part B: Engineering, In Press, 2018. DOI: 10.1016/j.compositesb.2018.05.046 [DOI] 🠔
  35. [35] Rao, J., Bao, L., Wang, B., Fan, M. and Feo, L., Plasma surface modification and bonding enhancement for bamboo composites. Composites Part B: Engineering , 138, pp. 157-167, 2018. DOI: 10.1016/j.compositesb.2017.11.025 [DOI] 🠔
  36. [36] Mohanty, A., Khan, M. and Hinrichsen, G., Influence of chemical surface modification on the properties of biodegradable jute fabrics-polyester amide composites. Composites Part A: Applied Science and Manufacturing, 31(2), pp. 143-150, 2000. DOI: 10.1016/S1359-835X(99)00057-3 [DOI] 🠔
  37. [37] Herrera, P. and Valadez, A., Mechanical properties of continuous natural fibre-reinforced polymer composites. Composites Part A: Applied Science and Manufacturing , 35(3), pp. 339-345, 2004. DOI: 10.1016/j.compositesa.2003.09.012 [DOI] 🠔
  38. [38] Focher, B., Palma, M., Canetti, M., Torri, G., Cosentino, C. and Gastaldi, G., Structural differences between non-wood plant celluloses: evidence from solid state NMR, vibrational spectroscopy and X-ray diffractometry. Industrial Crops and Products, 13, pp. 193-208, 2001. DOI: 10.1016/S0926-6690(00)00077-7 [DOI] 🠔
  39. [39] Shanmugasundaram, N., Rajendran, I. and Ramkumar, T., Characterization of untreated and alkali treated new cellulosic fiber from an Areca palm leaf stalk as potential reinforcement in polymer composites. Carbohydrate Polymers, 195, pp. 566-575, 2018. DOI: 10.1016/j.carbpol.2018.04.127 [DOI] 🠔
  40. [40] Chegdani, F. and El Mansori, M., Friction scale effect in drilling natural fiber composites. Tribology International, 119, pp. 622-630, 2018. DOI: 10.1016/j.triboint.2017.12.006 [DOI] 🠔
  41. [41] Sreenivasulu, S. and Chennakeshava, A., Mechanical properties evalution of bamboo fiber reinforced composite materials. International Journal of Engineering Research, [Online]. 3(1), pp. 187-194, 2014. [date of reference November 20th of 2017]. Available at: Available at: https://www.researchgate.net/publication/269412 025_Mechanical_Properties_Evaluation_of_Bamboo_Fiber_ [URL] 🠔
  42. [42] Huanga, Y., Benhua, F., Penglian, W. and Chang, Z., Mechanical properties of bamboo fiber cell walls during the culmdevelopment by nanoindentation. Industrial Crops and Products , 92, pp. 102-108, 2016. DOI: 10.1016/j.indcrop.2016.07.037 [DOI] 🠔
  43. [43] Arroyave, M., Nanocaracterización estructural y macánica de recubrimeintos duros de TiN y ZrN producidos por descarga de arco pulsado, MSc. Tesis, Departamento de física y química, Facultad de Ciencias y Administración, Universidad Nacional de Colombia, Manizales, Colombia, 2004. 🠔
How to cite: Espitia-Nery, M.E., Corredor-Pulido, D.E., Rodríguez-Ramírez, N.J., and Calderón-Bustos, J.N,. Morphological and nanomechanical characterization of Guadua Angustifolia kunth fiber by means of SEM and AFM. DYNA, 85(206), pp. 148-154, September, 2018.
M.E. Espitia-Nery, is a BSc. Physical Engineer, Sp. in Production and Operations Management, MSc. in Industrial Engineering, MSc. in Business Administration, and currently a student in the MBA program at the Universidad de los Andes. He has 10 years of experience in teaching, research and management of strategic plans, specialized in companies in the services and manufacturing sector in areas of production, operations and R&D + i. Consultant and lecturer in countries such as Spain, Brazil, Mexico, among others, in topics related to engineering, science and materials technology. He is currently a principal investigator in the GEIIC group. ORCID: 0000-0001-5626-3051
D.E. Corredor-Pulido, is a BSc. in Metallurgy Engineer, MSc. in Metallurgy at the Universidad de Concepción in Chile, and a researcher in the GEIIC research group. She is currently a full professor at the Corporación Universitaria Minuto de Dios, Colombia, Faculty of Engineering, a national and international speaker, and expert in ONAC scanning electron. ORCID: 0000-0003-3148-9219
N.J. Rodríguez-Ramírez, is a BSc. Civil Engineer at the Minuto de Dios University Corporation, Colombia. He is currently a member at SINCE, the Sustainable Construction and Structures Seedbed. He has delivered presentations on the characterization of composite materials at national and international events ORCID: 0000-0003-2062-3021
J.N. Calderón-Bustos, is a BSc. in Civil Engineer at the Minuto de Dios University Corporation, Colombia. She is currently a member at SINCE, the Sustainable Construction and Structures Seedbed. She has delivered presentations on the characterization of composite materials at national and international events. ORCID: 0000-0002-3570-6439