Relating structure and chain dynamics to ballistic performance in transparent epoxy networks exhibiting nanometer scale heterogeneity

POLYMER

卷:58

Article

Masser, Kevin A.¹  Knorr, Daniel B., Jr.¹  Hindenlang, Mark D.¹  Yu, Jian H.¹  Richardson, Adam D.¹  Strawhecker, Kenneth E.¹  Beyer, Frederick L.¹  Lenhart, Joseph L.¹ 

[1] US Army, Res Lab, Weap & Mat Res Directorate, Aberdeen Proving Ground, MD 21005 USA

关键词: Polymer networks;    Nanoscale heterogeneity;    Nanostructure;   

DOI  :  10.1016/j.polymer.2014.12.027

来源: Elsevier

【 摘 要 】

The ballistic performance was examined for a series of broad glass transition temperature epoxy formulations consisting of a di-epoxy monomer crosslinked with bi-modal mixtures of both a rigid, low molecular weight diamine and a flexible, high molecular weight diamine. Interestingly, the resins did not macro-phase separate during cure, but exhibited structural and dynamic heterogeneity on a length scale of a few nanometers, as confirmed by X-ray scattering, dynamic mechanical analysis, modulus-mapped atomic force microscopy, and broadband dielectric spectroscopy. The nano-structured resins were optically transparent and demonstrated a nearly 300% increase in ballistic energy dissipation relative to the neat resins, as well as when compared to epoxy formulations composed of similar bi-modal blends that exhibited a macro-phase separated structure. The ballistic performance is found to be insensitive to sub-glass transition temperature (T-g) relaxations, but appears to be dependent on both the nano-structure and the Vogel temperature of the high T-g component. The study demonstrates a new class of transparent protective materials composed of rigid and flexible components with a fine scale heterogeneous structure. Published by Elsevier Ltd.

【 授权许可】

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