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Effects of two‐dimensional programming on microstructures and thermal properties of shape memory polymer‐based composites
Author(s) -
Shen Dongya,
Shi Shuang,
Xu Tao
Publication year - 2017
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.45480
Subject(s) - charring , composite material , materials science , composite number , char , thermal stability , polymer , yield (engineering) , microstructure , layer (electronics) , thermal , chemical engineering , pyrolysis , physics , meteorology , engineering
To evaluate the effects of two‐dimensional (2D) programming on thermal properties of shape memory polymer (SMP)‐based composites when exposed to high temperature, the specimens of composites were prepared and programmed. Then the morphology, thermal properties, dynamic evolution, and constituents of released gaseous products were characterized. Results indicate that the programmed composite is more compacted, but the proportion of interconnected voids is larger than that in the nonprogrammed sample. 2D programming causes molecular or segmental orientations in SMP, and leads to the decrease in the char yield from 16.1 to 8.1%. The programmed sample shows a lower thermal stability. Further, the melting enthalpy of nonprogrammed composite is 1012 J/g which is lower than 1100 J/g of the programmed sample. The prestored stress in oriented molecules or segments of SMP is more prone to cause the chain scissions. The dynamic evolution and constituents of released volatiles from nonprogrammed and programmed samples are similar, but the release amount of volatiles from the latter is larger. Finally, the more compacted charring layer of nonprogrammed composite is more efficient to prevent volatiles from releasing out. The 2D programming has a slight influence on the elemental contents of O, Si, and C in the charring layer. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45480.