Heterogeneous nucleation of a semicrystalline polymer on fiber surfaces
Nucleation phenomenon as affected by the surface conditions of six identical wood/non-wood fibers with three levels of fiber treatments were investigated by a combination of complementary techniques. This study was based on results of a preliminary study on the influence of surface characteristics of thermomechanical pulp (TMP) fibers on the transcrystalline layer (TLC) growth and its correlation with interfacial strength properties. Surface morphology of fiber material and heterogeneous nucleation phenomenon on the fiber material was carried out using scanning electronic microscopy and polarizer light microscopy. The nucleation efficiency was examined in a polymer matrix to determine unity factors, which directly explains Gibbs free energy in a correlation of homogeneous and heterogeneous nucleation. The factor was generated from the crystalline deposit angle measurement on the fiber surface during isothermal crystallization temperature at 140o +- 0.1oC. Both measurements indicate that surface properties of extracted and surface washed fibers influence surface induced heterogeneous nucleation of polypropylene. Morphological changes on the fiber surface were reported due to an elimination of relation of relatively small particles from each level of surface treatment and fewer particles on the fiber surface indicated decreased nucleation ability on the surface.