Chemomechanics of dual-stage reprocessable thermosets
Chemomechanics of dual-stage reprocessable thermosets
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DOI：
10.1016/j.jmps.2019.02.013
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发表时间：
2019-05
影响因子：
5.3
通讯作者：
Chaoqian Luo;Biao Zhang;Wang Zhang;Chao Yuan;M. Dunn;Qi Ge;Kai Yu
中科院分区：
文献类型：
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作者：
Chaoqian Luo;Biao Zhang;Wang Zhang;Chao Yuan;M. Dunn;Qi Ge;Kai Yu
最近开发的双阶段3D打印可再加工热固性材料（3DPRT）利用丙烯酸酯官能团来实现基于紫外线的3D打印（阶段I），并采用键交换反应（BER）来定制用于机械性能增强的网络结构，并赋予传统不可加工的热固性材料再成形性、可修复性和可回收性（阶段II）。3DPRT提供了一个实用的解决方案，以应对与3D打印材料消耗快速增长相关的环境挑战。然而，由于发展的新生状态，在3DPRT的处理过程中的化学力学的基本理解仍然缺乏。在本文中，我们提出了详细的实验和理论研究，以了解在第二阶段的网络结构和热机械性能的演变的3DPRTs的热处理条件的影响。一个化学力学理论被定义为链接的分子水平的BER动力学的宏观尺度的热处理过程中的3DPRT的热机械性能。然后建立热粘弹性多分支本构模型，以捕获在第二阶段加工过程中的弹性和玻璃化转变行为。所开发的理论是能够捕获的力学性能增强的实验观察，并提供理论指导的网络设计和热处理条件的选择，以定制最终的力学性能的3DPRT。
The recently developed dual-stage 3D printing reprocessable thermosets (3DPRTs) utilize acrylate functional groups to enable the ultra-violet based 3D printing (Stage I), and employ bond exchange reaction (BERs) to tailor the network structure for mechanical properties enhancement and impart the reshapeability, reparability, and recyclability into traditionally unprocessable thermosets (Stage II). 3DPRT provides a practical solution to address environmental challenges associated with the rapid increase in the consumption of 3D printing materials. However, due to the nascent state of development, fundamental understanding of the chemomechanics during the processing of 3DPRTs is still lacking. In this paper, we present detailed experimental and theoretical studies to understand the effect of thermal treatment condition at Stage II on the evolution of network structure and thermomechanical properties of 3DPRTs. A chemomechanics theory is defined to link the molecular-level BER kinetics to the macroscale thermomechanical properties of 3DPRTs during the thermal treatment. A thermo-viscoelastic multi-branched constitutive model is then established to capture the elastic and glass transition behaviors during the Stage II processing. The developed theory is able to capture the experimental observations on the mechanical properties enhancement and provide theoretical guidance for the network design and the selection of thermal treatment conditions to tailor the final mechanical properties of 3DPRTs.