Low-intensity mixing process of high molecular weight polymer chains leads to elastomers of long network strands and high fatigue threshold
Low-intensity mixing process of high molecular weight polymer chains leads to elastomers of long network strands and high fatigue threshold
复制标题
高分子量聚合物链的低强度混合过程导致弹性体具有长网络链和高疲劳阈值
DOI：
10.1039/d3sm00687e
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发表时间：
2023
期刊：
影响因子：
3.4
通讯作者：
Suo, Zhigang
中科院分区：
文献类型：
--
作者：
Bao, Xianyang;Nian, Guodong;Kutsovsky, Yakov;Kim, Junsoo;Jiao, Quan;Suo, Zhigang
许多聚合物网络是通过交联聚合物链制备的。聚合物链和交联剂通常在内部混合器或辊磨机中混合。这些激烈的过程打破聚合物链，降低粘度，并易于混合。所得聚合物网络具有短链和疲劳阈值为~ 100 J m−2。在这里，我们表明，低强度工艺，揉捏和退火相结合，保留了长链，导致聚丁二烯网络达到440 J m−2的疲劳阈值。在一个网络中，每个链都有多个交联，这将链分成多个链。在链条的两端有两根悬垂的绳子，它们不能承受负荷。每条链的交联数量越大，悬垂链的比例就越低。高疲劳阈值要求较长的钢索，以及较低的悬垂钢索比例。一旦强烈的混合将链剪短，每个短链只能有几个交联；钢索较短，悬垂钢索比例较高，均降低了疲劳阈值。相比之下，低强度混合过程保留了长链，可以有许多交联；钢索较长，悬垂钢索的比例较低，两者都增加了疲劳阈值。希望这项工作将有助于抗疲劳弹性体的发展。
Many polymer networks are prepared by crosslinking polymer chains. The polymer chains and crosslinkers are commonly mixed in internal mixers or roll mills. These intense processes break the polymer chains, lower viscosity, and ease mixing. The resulting polymer networks have short chains and a fatigue threshold of ∼100 J m−2. Here, we show that a low-intensity process, a combination of kneading and annealing, preserves long chains, leading to a network of polybutadiene to achieve a fatigue threshold of 440 J m−2. In a network, each chain has multiple crosslinks, which divides the chain into multiple strands. At the ends of the chain are two dangling strands that do not bear the load. The larger the number of crosslinks per chain, the lower the fraction of dangling strands. High fatigue threshold requires long strands, as well as a low fraction of dangling strands. Once intense mixing cuts chains short, each short chain can only have a few crosslinks; the strands are short and the fraction of dangling strands is high—both lower the fatigue threshold. By contrast, a low-intensity mixing process preserves long chains, which can have many crosslinks; the strands are long and the fraction of dangling strands is low—both increase the fatigue threshold. It is hoped that this work will aid the development of fatigue-resistant elastomers.