Enhancing the Interface of PLA Composites Through Solution‐Based Processing

The strength of the fiber‐matrix interface plays a critical role in controlling the mechanical performance of polymer composites for various applications. The ability to characterize the strength of that interface accurately and efficiently is therefore extremely important. The objective of the present work is to determine the effect of a previously unexplored sample preparation method on the apparent interfacial shear strength (τ app ) obtained using the microbond test. The τ app of glass, carbon, and natural (flax) fibers with polylactic acid (PLA) was evaluated using two methods: the conventional polymer fiber tying method and a novel polymer solution casting method. The τ app was found to strongly depend upon the sample preparation method employed. The average τ app obtained for glass, carbon, and flax‐PLA was 31%, 8%, and 17% higher for solution cast droplets than for tied, respectively. These results illustrate the potential for solution processing as a route to improved thermoplastic composite performance.