*2.2. Filler Preparation Procedure*

The compositions of the reinforced PP created by using as-prepared filler and hybrid filler samples prepared in this study are listed in Table 1. The required amount of SiPs and CNFs was added into the ethanol/water mixed solvents and stirred for one hour. The mixture was then evaporated by using a rotary evaporator (Eyela N-1110, Tokyo Rikakiki Co., Ltd., Tokyo, Japan). Subsequently, it was dried under vacuum overnight before use.


**Table 1.** Sample composition of PP and filler.
