| Summary: | 碩士 === 朝陽科技大學 === 應用化學系 === 104 === The aim of this study is to compare the effects on mechanical and retardant properties of ploylactic acid (PLA) with different amount of recyclable chopstick fibers, unmodified ammonium polyphosphate (APP), and modified ammonium polyphosphate (EAPP). Modified ammonium polyphosphate was obtained by surface treatment of APP with a silane coupling agent, 3-glycidoxypropyltrimethoxysilane, in order to achieve the better compatibility between reinforcing material and PLA. A series of green composites were prepared by melt-blending with addition of APP, EAPP, chopstick fibers and PLA. The results of XPS analysis revealed that the amounts of C and Si of EAPP were higher than those of APP. Moreover, the thermal properties of PLA were enhanced significantly when 20 wt% of EAPP was added. Furthermore, the storage and loss moduli of the composites can be enhanced effectively by adding the modified fibers. This means that the addition of the fibers can reinforce the rigidity and toughness of PLA. According to the UL-94 analysis, the composites with EAPP can reach the highest retardant level V-0. Moreover, SEM analysis revealed that EAPP and PLA have a better compatibility, and fiber pull out phenomenon was not found. XRD crystallography revealed that adding the EAPP maintained the crystallization patterns of the PLA in the three-dimensional spherulite, which can reinforce the impact resistance properties effectively. These results indicated that EAPP can enhance the thermal resistance and flame retardant properties, and the chopstick fibers can reinforce the mechanical properties of PLA. Due to the chopstick fiber was recycled from litter, therefore as a reinforcing materials, it can lower the industrial costs and achieve the value of waste recycling.
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