The Study of Styrene Polymerization in the Presence of Montmorillonite Containing Living Free Radical Initiator

• Main Authors: Tsia, Chan-Chan, 蔡茜茜
• Other Authors: Wu, Jeng-Yue
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/11731826023074157733

碩士 === 國立中興大學 === 化學工程學系 === 89 === The purpose of this thesis was to investigate the effect of montmorillonite content, the concentration of TEMPO and reaction time on the synthesis of PS/MMT nanocomposites by in situ living free radical polymerization at 123℃. Polymerization of styrene in presence of montomorillonite（the montomorillonite’s dosage：1.55 and 3.10 wt%） containing living free radical initiator for 8 hours gave the chemical grafting of PS at 2.28 ~ 2.74 g/1gMMT without adding TEMPO and at 1.08 ~ 1.21 g/1gMMT with 0.005M TEMPO addition. The presence of TEMPO exhibited the linear dependence of versus conversion and showed the “living character” of the polymerization. The polydispersity index of 1.0 ~ 1.2 and the number-average molecular weight (Mn) of 50,000~ 90,000 polymer was obtained for 8-hour reaction period and XRD data showed a weak diffraction between 2.9 and 3.5 nm indicating trace amount of montomorillonite not exfoliated. Without the addition of TEMPO, the polydispersity is between 1.3 and 1.5 and the Mn of 170,000 ~ 230,000 could be obtained for 8-hour reaction period. The d-spacing greater than 4.4 nm after a reaction time of 6 hours was observed. In summary, we have demonstrated that PS/MMT nanocomposites can be directly polymerized via adsorbed living free radical initiator. Diversifying molecular weight and polydispersity of polystyrene grafted on the montomorillonite surface can be prepared by varying the external concentration of TEMPO.