| Summary: | 碩士 === 桃園創新技術學院 === 應用科技研究所 === 103 === Part 1
Palygorskite (AT) is natural and rigid reinforcing material as additive for biodegradable polylactic acid (PLA). To study the influences of different amount of AT on PLA material properties, the research has two parts: first, pure palygorskite (OAT) is obtained from purification of hexametaphosphate (SHMP); then, Brabender is used to blend palygorskite (AT) / polylactic acid (PLA) to prepare composite material (AT/PLA). Structural characterizations are conducted by Fourier transformation infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS). Thermal properties and mechanical properties are measured by thermogravimetric analysis (TGA) and universal tensile test machine (MTS). Differential scanning calorimetry (DSC) is used to understand the endothermic and exothermic behaviors for PLA nano-composite in crystallization and melting processes. Avrami equation is used to determine the crystal growth for the composite materials of different AT/PLAs ratios. FT-IR is used to determine the change of functional groups in AT/ PLA composite. Then, TGA is used to investigate the thermogravimetric behavior for AT/PLA and determine the thermal stability for AT/PLA composite. MTS test is used to investigate mechanical strength and tensile properties for AT/PLA. SEM is used to investigate the cross-section for the AT/PLA fracture surface. From TGA and MTS, it is found that the addition of AT can improve thermal properties and mechanical properties. But overdose of AT will decrease the thermal properties and mechanical properties for AT/PLA. XRD result indicates that the main AT crystallization peak clearly increases with increasing AT and the addition of AT does not affect PLA structure. With increasing AT, Si element in the composite material also increases, as shown in EDS, but the distribution of AT becomes poor. From the observation of crystallization behavior by differential scanning calorimetry analyzer (DSC), it is found that the addition of AT to PLA can help PLA nucleation, increase crystallization speed or shorten crystallization time.
Part 2
Acetyl tributyl citrate (ATBC) is a non-toxic and odorless plasticizer, which is suitable as additive for biodegradable polylactic acid (PLA). Palygorskite (AT) is natural, rigid and reinforcing filler. To study the influences of different amount of AT and ATBC on PLA material properties, the research uses Brabender to conduct melt blending to prepare the composite material (AT/PLA) from palygorskite (AT) and polylactic acid (PLA). Structural characterization is conducted by Fourier transformation infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS). Thermal properties and mechanical properties are measured by thermogravimetric analysis (TGA) and universal tensile test machine (MTS). FT-IR is used to determine the change of functional groups in PLA, AT/ PLA- ATBCs composite. Then, TGA is used to investigate the thermogravimetric behavior for AT/PLA- ATBCs and determine the thermal stability for AT/PLA- ATBCs composite. It is found that the addition of ATBC can increase thermal decomposition temperature and improve thermal stability. XRD result indicates that the addition of PLA into ATBC can increase the crystallization of PLA and improve the thermal stability. With increasing AT, the main AT crystallization peak increases significantly. From SEM observation, it is found that the addition of ATBC can increase the compatibility of PLA with the matrix, but the addition of excessive amount of AT can cause coagulation. EDS result shows that the content of Si, Mg, and Al increases with increasing AT.
Part 3
Polylactic acid (PLA) is a novel degradable polymer. PLA is a relatively hydrophobic material. It can be modified by grafting with maleic anhydride to increase the compatibility between palygorskite (AT) and PLA material. To study the influences of PLA modification and the addition of different amount of ATT on the composite material, the research has two parts: first, purified palygorskite (PAT) is obtained from the original palygorskite (OAT) by purification of hexametaphosphate (SHMP), and EDS and XRD are used to characterize the structural difference in purified palygorskite (AT); then, Brabender is used to blend palygorskite (AT) / modified polylactic acid (PLA) to prepare composite material (AT/PLA) and FT-IR is used to determine the change of functional groups in PLA-g-MAH/AT composite. Further, TGA is used to investigate the thermogravimetric behavior for PLA-g-MAH/AT and determine the thermal stability for PLA-g-MAH/AT composite material. It is found that the addition of maleic anhydride can decrease the thermal decomposition temperature. From SEM observation, it is found that the addition of maleic anhydride can increase PLA compatibility. EDS result also indicates that the content of Si, Mg and Al increases with increasing AT and the modified PLA can increase compatibility and dispersibility. XRD result shows that modification of PLA with maleic anhydride can increase PLA crystallinity.
|
|---|
