Microtension Test Method for Measuring Tensile Properties of Individual Cellulosic Fibers

A microtension testing system was devised to measure mechanical properties of individual cellulosic fibers. To avoid specimen gripping and to enhance fiber alignment during testing, a self-aligning ball and socket gripping assembly was used in the microtensile tester design. A resolution of 0.098 mN was obtained for the tensile load measurement with this microtensile tester. Fiber strain was determined from high-precision stepper motor movement with 0.078-μm resolution or by in situ video photography. Cross-sectional areas of a single fiber cell wall were measured with a confocal laser scanning microscope. Results obtained from this system indicated a linear stress-strain curve until fatal failure for mature latewood fibers, whereas juvenile latewood fibers displayed curvilinear stress-strain relationships. Average values of tensile strength, tensile modulus, and elongation at break were 1258 MPa, 19.9 GPa, and 6.6% for mature latewood fiber and 558 MPa, 8.5 GPa, and 9.9% for juvenile latewood fiber, respectively. These values agreed with published data. The preliminary test indicated the usefulness of the integrated environmental chamber for investigating moisture effect on fiber engineering properties, but further investigation is needed to obtain statistically significant data.

[1]  F. El-Hosseiny,et al.  mechanical properties of single wood pulp fibres. VI. Fibril angle and the shape of the stress-strain curve , 1983 .

[2]  H. F. Jang,et al.  Transverse dimensions of wood pulp fibres by confocal laser scanning microscopy and image analysis , 1992, Journal of Materials Science.

[3]  S. Shaler,et al.  The tensile testing of individual wood fibers using environmental scanning electron microscopy and video image analysis , 1995 .

[4]  J. Lambros,et al.  Micromechanical characterization of cellulose fibers , 2002 .

[5]  S. Shaler,et al.  Mechanical properties of individual southern pine fibers. Part I. Determination and variability of stress-strain curves with respect to tree height and juvenility , 2002 .

[6]  K. Zarrabi,et al.  Non-contacting creep strain determination at 550 °C , 2003 .

[7]  S. Stanzl-Tschegg,et al.  Microtensile Testing of Wood Fibers Combined with Video Extensometry for Efficient Strain Detection , 2003 .

[8]  C. Lim,et al.  Novel approach to tensile testing of micro- and nanoscale fibers , 2004 .

[9]  W. Gindl,et al.  The significance of the elastic modulus of wood cell walls obtained from nanoindentation measurements , 2004 .

[10]  M. Burghammer,et al.  Mechanical properties of cellulose fibres and wood. Orientational aspects in situ investigated with synchrotron radiation. , 2005, Journal of synchrotron radiation.

[11]  J. W. Provan,et al.  A procedure for measuring the flexibility of single wood-pulp fibres , 2006 .

[12]  Kenji Umemura,et al.  Characterization of the morphological, physical, and mechanical properties of seven nonwood plant fiber bundles , 2007, Journal of Wood Science.

[13]  C. Lim,et al.  Mechanical characterization of nanofibers – A review , 2006 .

[14]  K. M. M. Rao,et al.  Extraction and tensile properties of natural fibers : Vakka, date and bamboo , 2007 .

[15]  Jilei Zhang,et al.  Temperature and loading rate effects on tensile properties of kenaf bast fiber bundles and composites , 2008 .

[16]  Maya Jacob John,et al.  Biofibres and Biocomposites , 2008 .

[17]  I. Burgert,et al.  A close-up view of wood structure and properties across a growth ring of Norway spruce (Picea abies [L] Karst.) , 2009, Trees.

[18]  Atomic force microscopy for the measurement of flexibility of single softwood pulp fibres , 2008, Journal of Materials Science.

[19]  G. Pharr,et al.  Nanoindentation of juvenile and mature loblolly pine (Pinus taeda L.) wood fibers as affected by thermomechanical refining pressure , 2009, Wood Science and Technology.

[20]  S. V. Kamat.  Experimental Techniques for the Measurement of Mechanical Properties of Materials Used in Microelectromechanical Systems , 2009 .

[21]  W. M. Banks,et al.  Tensile Testing of Cellulose Based Natural Fibers for Structural Composite Applications , 2009 .

[22]  Tensile Properties of Kenaf Fiber Bundle , 2010 .

[23]  J. Michler,et al.  Nanoindentation of single pulp fibre cell walls , 2010 .