Characterizing Interphase Properties in Fiber Reinforced Polymer Composite with Advanced AFM Based Tools

摘要

Advanced atomic force microscopy techniques such as contact resonance force microscopy, noncontact mode phase imaging, and scanning thermal microscopy techniques have been used to characterize material properties in the interphase of fiber reinforced polymer composites. With contact resonance force microscopy, the average interphase thickness was found to be (49 ± 5) nm, (64 ± 12) nm, and (139 ± 21) nm for samples containing lyocell fibers in matrix materials consisting of 100% polypropylene (PP)/0% maleated polypropylene (MAPP), 95% PP/5% MAPP, and 90% PP/10% MAPP, respectively. Clear distinctions in modulus values between the fiber, interphase zone, and matrix are clearly visible in modulus images. A gradient of modulus was observed across the interphase region that ranged between the modulus values of fiber and the polymer matrix. Noncontact mode images showed a clear phase difference between the fiber, interphase, and matrix owing to the difference in material properties between the components. Interphase regions were observed to possess higher thermal conductivity than the matrix polymer due to cross-linking within the interphase.