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標題: Carbon Black Flame Retardant Containing IPNs based on Epoxy/Unsaturated Polyester
作者: 石燕鳳
Shih, Yeng-Fong
關鍵字: carbon black;活性碳;epoxy;unsaturated polyester;IPN;flame retardant;環氧樹脂;不飽和聚酯;互穿網狀型高分子;阻燃劑
出版社: 化學工程學系
由固態碳十三核磁共振光譜儀及霍氏紅外線光譜儀分析則發現不飽和聚酯與環氧樹脂之間有氫鍵作用力存在,且在某些混合比例時二者會有較佳的氫鍵作用力形成,因此具有較好的相容性。由動態力學分析(DMA)結果顯示,隨著不飽和聚酯添加量的增加,材料的阻尼溫度範圍逐漸拉寬並移向較低溫度。熱重分析(TGA)及調制型熱重分析(MTGA)則發現在互穿網狀型高分子材料中,不飽和聚酯和環氧樹脂的的分解反應係接近各自獨立進行、不會互相干擾的模式。而在加入膨脹型耐燃劑後,材料的熱裂解活化能提高,且活化能隨轉化率變化之曲線與未添加活性碳阻燃劑的IPN材料有明顯的不同。由熱裂解氣相層析/質譜儀分析也發現在加入活性碳阻燃劑後劣解產物種類明顯減少,且其中高分子量產物之含量增加,低分子量產物之比例則相對降低。DMA、 熱重分析(TGA)及耐燃性分析(LOI)皆顯示加入膨脹型耐燃劑後不僅提高材料的耐燃性,並改善材料的制振及機械性質。

A series of carbon black containing interpenetrating polymer networks (IPNs) based on unsaturated polyester/epoxy have been developed in this endeavor. Scanning electronic microscopy exhibits that the compatibility was decreased and the morphology seemed to become less rigid as the content of unsaturated polyester increased in IPNs. The results also indicate that the flame retardants were uniformly distributed in the IPN matrices. The compatibility and interaction behavior of these IPNs have been investigated by DMA, DSC, FTIR and solid-state NMR spectroscopies. The Tg's of IPNs were decreased and their transitions became broader as the content of unsaturated polyester increased in IPNs based on DMA and DSC study. Moreover, DSC measurements reveal that the Tg of the IPN sample became indistinct as the carbon black was added. This is due to the increase of inorganic content. Hydrogen bonding is present between the unsaturated polyester and epoxy as indicated by the FTIR investigation. Insufficient degree of hydrogen bonding brought about immiscibility between IPN components. The analysis of proton spin-lattice relaxation time in the rotating frame (TH1ρ) of the IPNs was also utilized to investigate molecular interaction between unsaturated polyester and epoxy. From relaxation curves, phase separation was found for the IPN samples with unsaturated polyester content higher than 30%. This was also observed by DMA study. Further DMA investigation indicates that the storage moduli were greatly enhanced with the addition of the carbon black to the IPN samples. Moreover, the loss modulus peaks became broader and more distinguished after addition. Based on the above, the addition of carbon blacks to IPN samples does greatly enhance the damping properties (at a wider temperature range) as well as the mechanical properties.
In the aspect of flame retardancy, the carbon black flame retardants would expand as heated over 220℃. Thermal degradation behavior and kinetic parameters of this system were analyzed by conventional and modulated thermogravimetric analysis (MTGA). It was found that the epoxy and unsaturated polyester components decomposed individually in the polymer network. Furthermore, the activation energy calculated from Ozawa method is somewhat lower than that of MTGA method.
This implies that the decomposition reaction is not a single reaction. Moreover, the activation energy of decomposition increased as carbon black flame retardants were added. The curves of activation energy versus residual mass varied in shape and position as the carbon black flame retardants were added. This indicates that the decomposition mechanism of carbon black-containing IPNs was different from that of the pristine IPNs. It was also found from adiabatic calorimeter that the heat of combustion (HOC) of the IPN sample was decreased by the addition of carbon black flame retardants. Moreover, the results of Py-GC-MS study reveal that the degradation of IPNs was derived from the non-interfering thermal decomposition processes of the respective IPN components. The degradation process of IPN was inhibited with the addition of the carbon black. This led to the lower content of low molecular weight compounds and fewer species of degradation products. In summary, the flame resistance, damping and mechanical properties were all improved simultaneously by the addition of the "plate-shaped" carbon black flame retardants to the unsaturated polyester/epoxy IPNs.
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