Viscoelastic properties and residual stresses in polyhedral oligomeric silsesquioxane‐reinforced epoxy matrices
Viscoelastic properties and residual stresses in polyhedral oligomeric silsesquioxane‐reinforced epoxy matrices
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多面体低聚倍半硅氧烷增强环氧基质的粘弹性和残余应力
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
S. Simon
中科院分区：
文献类型：
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作者：
Qingxiu Li;S. A. Hutcheson;G. McKenna;S. Simon
纤维填充热固性聚合物复合材料广泛应用于航空航天工业。这些材料的一个缺点是基体中固化引起的或热引起的残余应力，这可能导致性能劣化和过早失效。本文探讨了使用环氧树脂/多官能多面体低聚倍半硅氧烷（POSS）纳米复合材料作为树脂，降低热应力系数，从而减轻残余应力。研究了POSS负载量对环氧/POSS纳米复合树脂的热应力系数的影响，从低于b-松弛到a-松弛，或玻璃化转变温度（即，从100到180摄氏度），通过测量剪切模量和线性热膨胀系数。环氧树脂/POSS纳米复合材料的热应力系数是温度的强函数，在a松弛区随温度的降低而迅速降低，在b松弛区附近增加，然后在b松弛峰温度以下降低。随着POSS含量的增加，在a-松弛附近的热应力系数与纯树脂相比减小;然而，在b-松弛峰的温度以下，热应力系数随着POSS含量的增加而增加。V C 2008 Wiley Periodicals，
Fiber-filled thermosetting polymer composites are extensively used in aerospace industries. One disadvantage of these materials is cure induced or ther- mally induced residual stresses in the matrix, which may result in deteriorated per- formance and premature failure. This article explores the use of epoxy/multifunc- tional polyhedral oligomeric silsesquioxane (POSS) nanocomposites as resins with reduced thermal stress coefficients that result in mitigated residual stresses. The effect of POSS loading on the thermal stress coefficient of the epoxy/POSS nanocom- posite resins was investigated from below the b-relaxation to the a-relaxation, or glass transition temperature, (i.e., from � 100 to 180 � C) by measuring the shear modulus and linear thermal expansion coefficient. The thermal stress coefficient of the epoxy/POSS nanocomposites is found to be a strong function of temperature, decreasing rapidly with decreasing temperature through the a-relaxation region, increasing in the vicinity of the b-relaxation, and then decreasing below the tempera- ture associated with the peak in the b-relaxation. With increasing POSS content, the thermal stress coefficient is reduced compared with the neat resin in the vicinity of the a-relaxation; however, the thermal stress coefficient increases with increasing POSS content below the temperature of the b-relaxation peak. V C 2008 Wiley Periodicals,