Influence of Surface Characteristics of TMP Fibers to the Growth of TCL on the Linear Fiber Surface (I): Aspect in the Surface Roughness

摘要

This research focused on the influence of surface characteristics of thermomechanical pulp (TMP) fibers to define the correlation both surface properties to crystallinity of the polymers and to interfacial strength resulting from the increased crystallinity. For this study, the fiber roughness was analyzed using atomic force microscopy (AFM). The three scan sizes were 5 um, 2.5 um, and 1.25 um. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) for the thermal analysis and polarize optimum microscopy (POM) to observe the crystallization process were used. Six TMP fibers, which were pro- duced with two different wood sources (mature and juvenile) and three pressures (4,8, and 12 bar), were used for this study with 100 percent polypropylene (PP), 100 percent maleic anhydride polypropylene (MAPP), 99 percent PP/1 percent MAPP, and 95 percent PP/5 percent MAPP at 150 +-1℃. The highest crystallinity was achieved when the highest surface roughness of 8 bar juvenile fibers placed with 100 percent MAPP. Enhanced MAPP also increased transcrystallinity on the wood fiber surfaces, and nucleation density also associated with the amount of MAPP and surface morphology. Transcrystalline layers (TCL) were formed on the TMP fiber surfaces with 100 percent PP resulting from the increased surface roughness. The DMA and DSC result showed decreased crystallization temperature with increased surface roughness. The increased interfacial strength was also achieved using the highest surface roughness with the fiber failure from lap shear test samples. Consequently, opened functional groups by mechanical pulping process with an optimized pressure are an efficient way to obtain increased crystallinity and interfacial strength.