Polylactide/basalt fiber composites with tailorable mechanical properties: Effect of surface treatment of fibers and annealing

Basalt fiber (BF) was used to reinforce polylactide (PLA) to obtain new composites with potential structural or engineering applications. The composites with pristine BFs present evidently increased strength and modulus relative to neat PLA. After surface treatment, BF shows more evident reinforcing effect because the interfacial energy between BF and PLA decreases sharply from 27.40 to 8.58 mJ m−2. The physical network structure of BFs is also improved after their surface treatment, and as a result, the composites with treated BF have more tensile cycles and higher elongation levels than the one with pristine BF. After solid annealing, the mechanical strengths of systems were further improved because of cold crystallization of PLA. But composites show higher improvement level relative to neat PLA because the nucleation effect of BF enhances fiber-matrix interfacial adhesion. This work provides useful information on the preparation of BF filled PLA composites with tailorable structure and properties.