高软化点聚碳硅烷的合成及可纺性

doi:10.7503/cjcu20140272

摘要/Abstract

摘要：

采用聚二甲基硅烷经常压高温裂解法合成了聚碳硅烷(PCS), 研究了不同反应条件下缩聚反应的特点与分子量增长的模式, 探讨了聚碳硅烷的结构与可纺性之间的关系. 结果表明, 对应于不同分子量PCS之间的缩聚反应, 高温下PCS的缩聚反应分为分子量匀速增长和加速增长2种模式. 经匀速增长模式得到的PCS分子量呈双峰分布, 具有良好的可纺性, 而经加速增长模式得到的PCS因含有大量的支化结构, 分子量呈多峰分布, 可纺性较差, 甚至丧失可纺性. 通过控制反应条件使缩聚反应中分子量增长处于匀速模式, 合成了软化点为256~287 ℃, 数均分子量为2.3×10³且具有良好可纺性的聚碳硅烷.

关键词: 聚碳硅烷的合成, 高软化点, 可纺性, 缩聚反应

Abstract:

Polycarbosilane(PCS) was synthesized by polydimethylsilane as starting material via high-temperature-normal-pressure method. The characteristics of polycondensation reaction and the increase mode of molecular weight were investigated by changing the reaction conditions. Moreover, the relationship between structure and spinnability of PCS was discussed. The results show that the condensation reaction of PCS at high temperature can occur in two different ways, the steady growth of molecular weight and the accelerated growth of molecular weight, corresponding to the polycondensation reaction between molecule of PCS with different molecular weights. The PCS obtained by steady growth pattern had a bimodal molecular weight distribution which possessed good spinnability. However, PCS formed by the accelerated growth model contained too much branching structures, which exhibited multi peak molecular weight distribution and poor spinnability. High softening-point PCS(256—287 ℃) with a number average molecular weight of 2.3×10³ and good spinnability was successful synthesized by polycontrolling the polycondensation reaction condition to make it progress in the steady growth model.

Key words: Synthesis of polycarbosilane, High softening-point, Spinnability, Polycondensation reaction

中图分类号:

O631

TrendMD:

李永强, 宋永才. 高软化点聚碳硅烷的合成及可纺性. 高等学校化学学报, 2014, 35(10): 2272.

LI Yongqiang, SONG Yongcai. Synthesis and Spinnability of the High Softening-point Polycarbosilane^†. Chem. J. Chinese Universities, 2014, 35(10): 2272.

图/表 10

Table 1 Characteristics of PCS synthesized in different conditions

Sample	Reaction temperature/℃	Holding time/h	Softening point/℃	10^-3 $M ˉ n$	PDI^*	Yield(%)	Insoluble residue(%)
PCS-1	440	4	165—186	1.5	2.47	33.2	2.53
PCS-2	450	4	186—211	1.7	2.71	39.3	2.44
PCS-3	460	4	205—237	1.9	2.84	40.9	2.17
PCS-4	470	4	265	2.3	4.84	41.9	2.38
PCS-5	480	4	>300	4.8	6.02	15.2	41.82
PCS-6	450	6	194—224	1.8	2.96	41.7	2.39
PCS-7	450	8	209—242	1.9	3.22	42.0	2.40
PCS-8	450	12	229—263	2.1	3.70	46.7	2.43
PCS-9	450	16	256—287	2.3	4.09	48.6	2.42
PCS-10	450	24	>300	2.7	5.30	51.8	2.64

Table 1 Characteristics of PCS synthesized in different conditions

Sample	Reaction temperature/℃	Holding time/h	Softening point/℃	10^-3 $M ˉ n$	PDI^*	Yield(%)	Insoluble residue(%)
PCS-1	440	4	165—186	1.5	2.47	33.2	2.53
PCS-2	450	4	186—211	1.7	2.71	39.3	2.44
PCS-3	460	4	205—237	1.9	2.84	40.9	2.17
PCS-4	470	4	265	2.3	4.84	41.9	2.38
PCS-5	480	4	>300	4.8	6.02	15.2	41.82
PCS-6	450	6	194—224	1.8	2.96	41.7	2.39
PCS-7	450	8	209—242	1.9	3.22	42.0	2.40
PCS-8	450	12	229—263	2.1	3.70	46.7	2.43
PCS-9	450	16	256—287	2.3	4.09	48.6	2.42
PCS-10	450	24	>300	2.7	5.30	51.8	2.64

Fig.1 GPC curves of PCS synthesized in different conditions (A) Reaction under different temperature for 4 h. a. 440 ℃; b. 450 ℃; c. 460 ℃; d. 470 ℃; e. 480 ℃. (B) Reaction under 450 ℃ for different holding time. a. 4 h; b. 6 h; c. 8 h; d. 12 h; e. 16 h; f. 24 h.

Fig.2 Influence of reaction conditions on Mˉn (A) Reaction time: 4 h; (B) reaction temperature: 450 ℃.

Scheme 1 Model of condensation reaction between PCS molecule

Fig.3 Influence of reaction conditions on contents of MH(a), MM(b) and ML(c) of PCS (A) Reaction time: 4 h; (B) reaction temperature: 450 ℃.

Fig.4 1H NMR(A) and 29Si NMR(B) spectra of KD-PCS(a), PCS-4(b) and PCS-9(c)

Fig.5 FTIR spectra of KD-PCS(a), PCS-4(b) nd PCS-9(c)

Fig.6 Influence of reaction conditions on ASi—H/ASi—CH3(a) and ASi—CH2—Si/ASi—CH3(b) (A) Reaction under different temperature for 4 h; (B) reaction under 450 ℃ for different holding time.

Table 2 Melting spinning conditions and spinnability of PCS

Sample	$T a *$ /℃	Temperature/℃	Pressure/MPa	Spin-speed/(r·min^-1)	Continuous time/min	Diameter/μm	Spinnability
PCS-1	165	305	0.5	350	>30	14.9	Very good
PCS-2	186	326	0.5	350	>30	15.2	Very good
PCS-3	205	345	0.5	350	>30	15.4	Very good
PCS-4	265	405	0.7	200	<1	17.2	Unspinnable
PCS-6	194	335	0.5	350	>30	15.6	Very good
PCS-7	209	350	0.5	350	>30	15.3	Very good
PCS-8	229	370	0.5	300	27	16.2	Good
PCS-9	256	400	0.5	350	17	14.8	Good
PCS-9	256	400	0.5	450	8	10.6	Good

Table 2 Melting spinning conditions and spinnability of PCS

Sample	$T a *$ /℃	Temperature/℃	Pressure/MPa	Spin-speed/(r·min^-1)	Continuous time/min	Diameter/μm	Spinnability
PCS-1	165	305	0.5	350	>30	14.9	Very good
PCS-2	186	326	0.5	350	>30	15.2	Very good
PCS-3	205	345	0.5	350	>30	15.4	Very good
PCS-4	265	405	0.7	200	<1	17.2	Unspinnable
PCS-6	194	335	0.5	350	>30	15.6	Very good
PCS-7	209	350	0.5	350	>30	15.3	Very good
PCS-8	229	370	0.5	300	27	16.2	Good
PCS-9	256	400	0.5	350	17	14.8	Good
PCS-9	256	400	0.5	450	8	10.6	Good

Fig.7 SEM images of the surface(A) and cross sections[insets of (A) and (B)] PCS-9 fibers span at different winding speeds of 350 r/min(A) and 450 r/min(B)

参考文献 26

[1]	Herzog A., Thunemann M., Vogt U., Beffort O., J. Eur. Ceram. Soc., 2005, 25(2), 187—192
[2]	Zhao D. F., Wang H. Z., Li X. D., J. Inorg. Mater., 2009, 24(6), 1097—1104
[3]	Chu Z. Y., Cheng H. F., Zhou Y. J., Wang Q., Wang J., Mater. Des., 2010, 31(6), 3140—3145
[4]	Laine R. M., Babonneau F., Chem. Mater., 1993, 5(3), 260—279
[5]	Birot M., Pillot J. P., Dunogues J., Chem. Rev., 1995, 95(5), 1443—1477
[6]	Yajima S., Hasegawa Y., Hayashi J., J. Mater. Sci., 1978, 13(12), 2569—2576
[7]	Okada K., Process for Producing Silicon Carbide Fiber, UP 6316051, 2001-11-13
[8]	Bunsell A. R., Piant A., J. Mater. Sci., 2006, 41(3), 823—839
[9]	Zhu Y. H., Wang H., Shao C. W., Chem. J. Chinese Universities,2013, 34(10), 2415—2420
	(朱旖华, 王浩, 邵长伟. 高等等学校化学学报, 2013, 34(10), 2415—2420)
[10]	Xue J. G., Chu Z. Y., Feng C. X., Xu J. D., Journal of National University of Defense Technology,2001, 23(5), 36—41
	(薛金根, 楚增勇, 冯春祥, 徐杰栋. 国防科技大学学报, 2001, 23(5), 36—41)
[11]	Idesaki A., Okamura K., Sugimoto M., Tanaka S., Morita Y., Seguchi T., Itoh M., Narisawa M., J. Mater. Sci., 2001, 36(23), 5565—5569
[12]	Hasegawa Y., Okamura K., J. Mater. Sci., 1983, 18(12), 3633—3648
[13]	Hasegawa Y., J. Mater. Sci., 1989, 24(4), 1177—1190
[14]	Bunsell A. R., Piant A., J. Mater. Sci., 2006, 41(3), 823—839
[15]	Toreki W., Batich C. D., Sacks M. D., Saleem M., Choi G. J., Morrone A. A., Comp. Sci. Technol., 1994, 51(2), 145—159
[16]	Hasegawa Y., J. Inorg. Organomet. Polym., 1992, 2(1), 161—169
[17]	Hasegawa Y., Compos. Sci. Technol., 1994, 51(2), 161—166
[18]	Li W., Song Y. C., Mao X. H., J. Mater. Sci., 2004, 41(21), 7011—7018
[19]	Cheng X. Z., Xie Z. F., Song Y. C., Xiao J. Y., Synthesis of Polycarbosilane at High Temperature and Under High Pressure Method, CN 200410023185.4,2005-01-26
	(程祥珍, 谢征芳, 宋永才, 肖加余. 高温高压合成聚碳硅烷的方法, CN 200410023185.4, 2005-01-26)
[20]	Chu Z. Y. , Liu H., Wang Y. D., Feng C. X. , Song Y. C., Zou Z. C., Journal of National University of Defense Technology,2002, 24(1), 39—43
	(楚增勇, 刘辉, 王应德, 冯春祥, 宋永才, 邹治春. 国防科技大学学报, 2002, 24(1), 39—43)
[21]	Yang D.X., Novel Methods for the Synthesis of PCS and PMCS and Production of High Temperature Resistant SiC Fibers, National University of Defense Technology, Changsha, 2008
	(杨大祥, PCS和PMCS的新合成方法及高耐温性SiC纤维的制备研究, 长沙: 国防科技大学, 2008)
[22]	Song Y. C., Shang Y., Feng C. X., Lu Y., Acta Polym. Sinica,1995, 12(6), 753—757
	(宋永才, 商瑶, 冯春祥, 陆逸. 高分子学报, 1995, 12(6), 753—757)
[23]	Xue J. G., Wang Y. D., Song Y. C., Qin M. L., Journal of National University of Defense Technology,2006, 28(2), 35—38
	(薛金根, 王应德, 宋永才, 秦墨林. 国防科技大学学报, 2006, 28(2), 35—38)
[24]	Cheng X. Z., Xie Z. F., Song Y. C., Xiao J. Y., Acta Polym. Sinica,2007, 1(1), 1—7
	(程祥珍, 谢征芳, 宋永才, 肖加余. 高分子学报, 2007, 1(1), 1—7)
[25]	Hasegawa Y., Okamura K., J. Mater. Sci., 1986, 21(1), 321—328
[26]	Hasegawa Y., Iimura M., Yajima S., J. Mater. Sci., 1980, 15(3), 720—728