Effect of surface modification of bamboo cellulose fibers on mechanical properties of cellulose/epoxy composites

Bamboo cellulose fibers were treated with NaOH aqueous solution and silane coupling agent, respectively, before they were applied into epoxy composites. The effect of surface modification on mechanical properties was evaluated by tensile and impact tests under controlled conditions. Compared with the untreated cellulose filled epoxy composites, the NaOH solution treatment increased the tensile strength by 34% and elongation at break by 31%. While silane coupling agent treatment produced 71% enhancement in tensile strength and 53% increase in elongation at break. The scanning electron microscopy (SEM) was used to observe the surface feature of the cellulose fibers and the tensile fractures as well as cryo-fractures of the composites. The Fourier transform infrared (FTIR) was employed to analyze the chemical structure of the cellulose fibers before and after modifications. The results indicated different mechanisms for the two modifications of cellulose. The NaOH solution partly dissolved the lignin and amorphous cellulose, which resulting in splitting the fibers into smaller size. This led to easier permeating into the gaps of the fibers for epoxy resin (EP) oligmer and forming effective interfacial adhesion. Based on the emergence of Si–O–C and Si–O–Si on the cellulose surface, it was concluded that the enhancement of mechanical properties after coupling agent modification could be ascribed to the formation of chemical bonds between the cellulose and the epoxy coupled with the coupling agent.

[1]  M. Jawaid,et al.  Bamboo fibre reinforced biocomposites: A review , 2012 .

[2]  Xinwen Peng,et al.  Laccase and alkali treatments of cellulose fibre: Surface lignin and its influences on fibre surface properties and interfacial behaviour of sisal fibre/phenolic resin composites , 2010 .

[3]  Sung-Hoon Ahn,et al.  An overview on the cellulose based conducting composites , 2012 .

[4]  K. Hsieh,et al.  Graft interpenetrating polymer networks of urethane-modified bismaleimide and epoxy (I): mechanical behavior and morphology , 2001 .

[5]  S. Billington,et al.  Mechanical response of PHB- and cellulose acetate natural fiber-reinforced composites for construction applications , 2011 .

[6]  P. Askeland,et al.  Surface modification of microfibrillated cellulose for epoxy composite applications , 2008 .

[7]  Shiyan Chen,et al.  In situ synthesis of CdS nanoparticles on bacterial cellulose nanofibers , 2009 .

[8]  E. Piorkowska,et al.  Mechanical and thermal properties of PLA composites with cellulose nanofibers and standard size fibers , 2011 .

[9]  Hao Wang,et al.  Mechanical properties of chemically-treated hemp fibre reinforced sandwich composites , 2012 .

[10]  Harriëtte L. Bos,et al.  Reinforcement of polypropylene by annual plant fibers: optimisation of the coupling agent efficiency , 2000 .

[11]  I. Low,et al.  Mechanical properties and water absorption behaviour of recycled cellulose fibre reinforced epoxy composites , 2012 .

[12]  S. A. Stern,et al.  Solubility and diffusivity of light gases in ethyl cellulose at elevated pressures Effects of ethoxy content , 1997 .

[13]  J. E. Puig,et al.  Flexural, impact and compressive properties of a rigid-thermoplastic matrix/cellulose fiber reinforced composites , 2002 .

[14]  A. Ragauskas,et al.  Novel nanocellulosic xylan composite film , 2009 .

[15]  A. Duarte,et al.  Modification of cellulosic fibres with functionalised silanes: development of surface properties , 2004 .

[16]  P. Herrera-Franco,et al.  Effect of fiber treatment on the mechanical properties of LDPE-henequen cellulosic fiber composites , 1997 .

[17]  M. Shukla,et al.  Tensile and structural characterization of alkali treated Borassus fruit fine fibers , 2013 .

[18]  I. Low,et al.  Mechanical and fracture properties of cellulose-fibre-reinforced epoxy laminates , 2007 .

[19]  Chengjun Zhou,et al.  Mechanical properties and in vitro degradation of electrospun bio-nanocomposite mats from PLA and cellulose nanocrystals. , 2012, Carbohydrate polymers.

[20]  C. Hill,et al.  Silane coupling agents used for natural fiber/polymer composites: A review , 2010 .

[21]  A. Mamun,et al.  Barley husk and coconut shell reinforced polypropylene composites: The effect of fibre physical, chemical and surface properties , 2010 .

[22]  Hao Wang,et al.  A review on the tensile properties of natural fiber reinforced polymer composites , 2011 .

[23]  M. Misra,et al.  The influence of chemical surface modification on the performance of sisal‐polyester biocomposites , 2002 .

[24]  Junhui He,et al.  Facile In Situ Synthesis of Noble Metal Nanoparticles in Porous Cellulose Fibers , 2003 .

[25]  R. El-Hajjar,et al.  Mechanical characterization of cellulose nanofiber and bio-based epoxy composite , 2012 .

[26]  V. Puri,et al.  Alkali‐explosion pretreatment of straw and bagasse for enzymic hydrolysis , 1986, Biotechnology and bioengineering.

[27]  Lívia Dányádi,et al.  Effect of various surface modifications of wood flour on the properties of PP/wood composites , 2010 .

[28]  M. Gabr,et al.  Effect of microfibrillated cellulose on mechanical properties of plain-woven CFRP reinforced epoxy , 2010 .

[29]  C. Vasile,et al.  Low density polyethylene composites containing cellulose pulp fibers , 2012 .

[30]  Richard P. Wool,et al.  Natural fiber composites with plant oil-based resin , 2004 .

[31]  Y. Shih.  Mechanical and thermal properties of waste water bamboo husk fiber reinforced epoxy composites , 2007 .

[32]  N. Suppakarn,et al.  Effect of glass fiber hybridization on properties of sisal fiber–polypropylene composites , 2009 .

[33]  T. Matsuura,et al.  Study on cellulose acetate membranes for reverse osmosis and polyethersulfone membranes for ultrafiltration by electron spin resonance technique , 2002 .

[34]  Jae Ryoun Youn,et al.  Thermal stability and flammability of coconut fiber reinforced poly(lactic acid) composites , 2012 .

[35]  A. Vázquez,et al.  Flexural properties loss of unidirectional epoxy/fique composites immersed in water and alkaline medium for construction application , 2012 .