采用不同升温速率的热失重(TGA)研究了紫外光固化巯基-乙烯基硅氮烷共聚产物的热解动力学,并采用Kissinger、Friedman和Vachuska-Voboril等方法对热解动力学参数进行了计算.结果表明,该共聚物在300℃～450℃,450℃～600℃和700℃～800℃出现了三个明显的失重峰,且分解活化能随热解温度升高逐渐增大,反应级数变小.采用热失重-质谱联用(TGA-MS)和红外光谱对热解产生的气体及热解转化物进行了分析,提出了热裂解历程,在第一和第二阶段主要是由于发生偶合脱氢、转胺基反应和脱羧反应产生了H_2、NH_3和CO_2,硫主要是以H_2S和SO_2形式脱除,并伴有少量的噻吩;第三阶段以Si-C和C-H断裂产生H_2和CH_4气体为主.
The ceramic precursor derived from UV curable multi thiol-vinyl containing silizane can be converted to Si_3N_4 at higher temperature in N_2 atmosphere. The pyrolysis process of this precursor was investigated by means of thermogravimetric analysis(TGA), TGA-mass spectroscopy and Fourier-transform infrared spectroscopy. The kinetic parameters of thermal degradation were determined by Kissinger, Friedman and Vachuska-Voboril methods. There are three DTG peaks which locate at the temperature ranges of 300℃～450℃(1~(st) stage), 450℃～600℃(2~(nd) stage)and 700℃～800℃(3~(rd) stage), respectively. The results show that apparent activation energy increases and reaction order decreases during pyrolysis. In the first stage, transamination reaction leads to release of NH_3, while dehydreoupling reaction between Si - H and Si - H(or N - H)causes H_2 evolution. With the increase of pyrolytic temperature, -C(= O)-O- chemical bonds break down, and gives off CO_2 at the same time. In the third stage,H_2 and CH_4 evolve due to dehycroupling of C- H and demethylate reaction. Whereas, S element in the copolymer releases mainly as H——2S and SO_2.
参考文献
| [1] | 宋家乐,陈立新,王亚洲,王汝敏.多元α-巯基丙酸酯/乙烯基硅氮烷紫外光固化与热解特性[J].高等学校化学学报,2007(09):1801-1803. |
| [2] | Cramer NB.;Reddy SK.;O'Brien AK.;Bowman CN. .Thiol-ene photopolymerization mechanism and rate limiting step changes for various vinyl functional group chemistries[J].Macromolecules,2003(21):7964-7969. |
| [3] | 李彦武,胡海峰,陈朝辉.含乙烯基聚硅氮烷的裂解过程分析[J].有机硅材料,2002(02):14-17. |
| [4] | 胡海峰,陈朝辉,冯春祥,张长瑞,宋永才.聚硅氮烷在氨气中的裂解研究[J].高分子学报,1998(01):104-108. |
| [5] | Liang, HB;Ding, J;Shi, WF .Kinetics and mechanism of thermal oxidative degradation of UV cured epoxy acrylate/phosphate triacrylate blends[J].Polymer Degradation and Stability,2004(2):217-223. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%