Effect of the addition of 4,4-methylene diphenyl diisocyanate and silicate on the thermal and mechanical properties of polylactide

• Main Authors: Po-Hsin Li, 李柏炘
• Other Authors: Ming -Chian Yang
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/ja8c9n

碩士 === 國立臺灣科技大學 === 高分子系 === 95 === In the first part of this work, MDI was added to PLA matrix as a cross-linking agent to extend the chain length, in order to improve the thermal and mechanical properties of PLA. The resulting polymer was examined using IR and ESCA to characterize the surface composition and chemical bondings. The termal properties were measured using DSC and TGA. The mechanical properties were determined using a tensile tester. The hydrophilicity was evaluated with the water contact angle measurements. The biodegradability was tested with esterase. The samples also were treated at 170°C to investigate the effect of heat treatment. The results show that when the content of MDI was at the equivalent point (0.0025 g/ 2 g PLA), the Tg can be elevated from 53°C to 64 °C, and the tensile strength can be increased from 4.9 MPa to 5.2 MPa. Furthermore, the breaking elongation can also be increased from 3% to 5%. Thus, both the tensile and thermal properties of PLA were improved. In the second part of this work, SiO2 particles were blened with PLA. The results show that the addition of SiO2 would not increase the Tg. When the content of SiO2 was 10%, the breaking elongation was increased to 12%. Thus the ductility of PLA was improved. Furthermore, the Tm of MDI-PLA also increased with the content of SiO2.