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分子量对PAMS热降解等温活化能的影响

陈苗 张占文 黄勇 史瑞廷 易勇 王红斌

陈苗, 张占文, 黄勇, 等. 分子量对PAMS热降解等温活化能的影响[J]. 强激光与粒子束, 2018, 30: 112001. doi: 10.11884/HPLPB201830.180184
引用本文: 陈苗, 张占文, 黄勇, 等. 分子量对PAMS热降解等温活化能的影响[J]. 强激光与粒子束, 2018, 30: 112001. doi: 10.11884/HPLPB201830.180184
Chen Miao, Zhang Zhanwen, Huang Yong, et al. Effect of molecular weight on isothermal activation energy of PAMS thermal degradation[J]. High Power Laser and Particle Beams, 2018, 30: 112001. doi: 10.11884/HPLPB201830.180184
Citation: Chen Miao, Zhang Zhanwen, Huang Yong, et al. Effect of molecular weight on isothermal activation energy of PAMS thermal degradation[J]. High Power Laser and Particle Beams, 2018, 30: 112001. doi: 10.11884/HPLPB201830.180184

分子量对PAMS热降解等温活化能的影响

doi: 10.11884/HPLPB201830.180184
基金项目: 

国家自然科学基金项目 v1530260

详细信息
    作者简介:

    陈苗(1994-), 女, 硕士, 从事ICF靶丸原材料热降解研究; cmzxy1102@163.com

    通讯作者:

    张占文(1973-), 男, 研究员, 博士, 主要从事激光聚变靶的研究与制备; bjzzw1973@163.com

  • 中图分类号: TQ325.2

Effect of molecular weight on isothermal activation energy of PAMS thermal degradation

  • 摘要: 聚α-甲基苯乙烯(PAMS)是制备激光惯性约束聚变(ICF)用靶丸的重要芯轴材料之一。采用快速热解气相色谱-质谱法(Py-GC-MS)和热重分析技术(TG/DTG)分析了不同分子量PAMS的热降解产物和热降解温度,并通过Arrhenius方程计算了不同分子量PAMS的等温热降解活化能。结果表明:分子量对PAMS热降解产物的影响可忽略不计,其热降解产物均为α甲基苯乙烯单体,且产率均接近100%;热降解温度随PAMS分子量的增加而降低,其热降解温度介于240~450 ℃之间;在相同降解率下,随分子量的减小,PAMS的热降解活化能增加,且PAMS的热降解活化能随着热降解率的增加而增加。
  • 图  1  不同分子量PAMS热裂解色谱图

    Figure  1.  Chromatogram of PAMS with different molecular weight

    图  2  不同分子量PAMS热降解过程中的TG和DTG图

    Figure  2.  TG and DTG curves of PAMS with different molecular weight

    图  3  不同分子量PAMS的热降解率随时间的关系

    Figure  3.  Thermal degradation rate of PAMS with different molecular weight, as a function of time at different temperature

    图  4  由等式(4)计算得到的Int与1/T关系图

    Figure  4.  Plot according to Eq.(4) from which activation energy for decomposition at various conversions can be calculated

    图  5  PAMS热降解过程示意图

    Figure  5.  Course sketch of thermal degradation mechanism of PAMS

    表  1  PAMS的分子量及分子量分布

    Table  1.   Molecular weight and molecular weight distribution of PAMS

    sample Mw/(g·mol-1) Mn/(g·mol-1) Mw/Mn supplier
    PAMS-1# 1.5×104
    PAMS-2# 3.1×105 3.1×105 1.018 synthesized
    PAMS-3# 4.5×105 3.9×105 1.15 synthesized
    下载: 导出CSV

    表  2  在500 ℃下不同分子量PAMS的热裂解产物

    Table  2.   Pyrolysis products of PAMS with different molecular weight at 500 ℃

    No. time/min molecular formula name of compound molecular structure Mw/(g·mol-1)
    1 4.5 C7H8 toluene 92
    2 5.4 C8H10 dimethybenzene 106
    3 5.7 C8H10 dimethylbenzene 106
    4 5.9 C9H12 isopropybenzene 120
    5 6.7 C9H10 alpha-methylstyrene 18
    6 6.9 C10H12 2-Methyl-3-Phenylpropene 132
    下载: 导出CSV

    表  3  不同分子量PAMS的热降解温度

    Table  3.   Thermal degradation temperature of PAMS with different molecular weight

    sample Tmax/℃ Tonset/℃ Tend/℃
    PAMS-1# 344.0 305.1 381.6
    PAMS-2# 320.6 287.8 336.9
    PAMS-3# 317.2 281.2 332.1
    下载: 导出CSV

    表  4  计算得到的分子量PAMS活化能

    Table  4.   Activation energies of PAMS corresponding to various percentages of decomposition

    thermal of degradation/% 1.5×104 3.1×105 2.5×105
    slope E/kJ slope E/kJ slope E/kJ
    30 20.24 168.27 8.99 74.74 8.97 74.58
    50 22.62 188.06 13.35 110.99 10.3 85.63
    70 23.13 192.30 19.04 158.30 11.95 99.35
    90 24.63 204.77 22.93 190.64 19.61 163.03
    下载: 导出CSV
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出版历程
  • 收稿日期:  2018-06-29
  • 修回日期:  2018-09-10
  • 刊出日期:  2018-11-15

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