Surface energy characterization of bamboo fiber determined by dynamic contact angle analysis.

In regards to the characteristics of uneven thickness and a larger variability of natural plant fibers, average wetting perimeter and dynamic contact angle of bamboo fiber were determined by using Whihelmy technique. Surface energy, dispersion and polar components of fiber were characterized under 11 types of wetting speed by Owens-Wendt method. Also, the relationships between wetting speed and dynamic contact angle, wetting speed and surface energy were investigated with the help of marginal mean. The results showed that: the method of using average wetting perimeter of 30 fibers to estimate the circumference and dynamic contact angle was feasible, with a smaller relative error of 0.69%. As the testing rate increased, dynamic advancing contact angles imitated the molecular dynamics model, rapid rising at initial stage and then gradually level off, while surface energy showed a non鄄linear decreasing trend. Surface energy of bamboo fiber was calculated as 41.71 -43.61 mN / m when testing speed was set as 1 -3 mm/ min. Consistent subset analysis represented that marginal mean of dynamic contact angle at 11 levels can be divided into 7 groups, and each group can be considered as a subset. Dynamic contact angle was significantly increased under the high testing speed compared with the low one. Correlation and partial correlation analysis showed that 14.11% degree of correlation between dynamic contact angle and testing speed determined from synergies effect of testing liquid. It has a negative linear relation between the value of bamboo fiber'surface energy and marginal mean of dynamic advancing contact angle.