Jointly modified mechanical properties and accelerated hydrolytic degradation of PLA by interface reinforcement of PLA-WF.

Polylactic acid (PLA), one of the most likely green and environmentally friendly materials, is an alternative to petroleum-based plastic. It still remains a challenge to increase the degradation rate and decrease the cost of PLA without compromised mechanical properties. Low cost PLA/wood flour (WF) composite was elaborately designed and fabricated with improved interface compatibility through the introducing of polymethyl methacrylate (PMMA). The result indicated that compared with that of neat PLA, the tensile strength and bending strength of PLA/WF/PMMA (8:2) (80 wt% of the PLA, 20 wt% of WF and PMMA (8:2)) were increase by 4.60% and 26.54% respectively. Through the hydrolysis experiments combined with the SEM analysis, the main reason for the improvement of the mechanical properties of composite materials was that PMMA makes continuous three-phase composition, and interface compatibility of PLA and WF with overly different polarity was modified. Meanwhile, the hydrolysis rate of PLA/WF/PMMA was much faster than that of PLA. Finally, there was a more significant discovery that the addition of PMMA changed material degradation mechanism, and it was why to efficiently accelerate the degradation rate of the material. This will provide a new inspiration for PLA degradation research, and a fresh perspective is to be given other materials.