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Are RAFT and ATRP Universally Interchangeable Polymerization Methods in Network Formation?
Macromolecules ( IF 5.1 ) Pub Date : 2021-09-16 , DOI: 10.1021/acs.macromol.1c01587
Julia Cuthbert 1 , Shiwanka V. Wanasinghe 2 , Krzysztof Matyjaszewski 1 , Dominik Konkolewicz 2
Affiliation  

Polymer networks were synthesized by both ATRP and RAFT to evaluate whether the choice of reversible deactivation radical polymerization method impacted the materials’ characteristics at either the molecular or bulk property level. Since control in ATRP is gained through interactions of a small-molecule catalyst with the polymer chain end, rather than degenerative transfer between two polymer chain ends, ATRP could lead to better controlled networks, particularly after gelation. In general, both RAFT and ATRP gave better controlled materials than the corresponding FRP processes. In general, RAFT reached higher conversions with higher gel fractions. The molecular properties indicate relatively small differences in control over the primary polymer chain length and the dispersity of the primary chains at lower targeted chain lengths of 100 or 200 units. However, ATRP provided better controlled polymers at longer primary chain lengths of 500 units. Both RAFT and ATRP networks swelled to greater extents than their conventional radical analogs, with ATRP giving somewhat higher swelling ratios at longer primary chain lengths and lower crosslink densities. Rheological analysis indicates that both materials are similar, although RAFT gave materials with higher elastic moduli, consistent with the higher conversion and lower sol fraction in RAFT. Overall, both RAFT and ATRP formed materials with similar properties at lower chain lengths, with ATRP appearing to yield slightly better properties at longer chain lengths. The control in RAFT and ATRP is likely through soluble components, including the small-molecule catalyst in ATRP and soluble polymer fractions (sol) in RAFT.

中文翻译:

RAFT 和 ATRP 在网络形成中是通用的可互换聚合方法吗?

聚合物网络由 ATRP 和 RAFT 合成,以评估可逆失活自由基聚合方法的选择是否影响了材料在分子或本体性能水平上的特性。由于 ATRP 的控制是通过小分子催化剂与聚合物链端的相互作用获得的,而不是两个聚合物链端之间的退化转移,因此 ATRP 可以导致更好的控制网络,特别是在凝胶化后。一般来说,RAFT 和 ATRP 都比相应的 FRP 工艺提供更好的受控材料。一般而言,RAFT 以较高的凝胶分数达到较高的转化率。分子特性表明,在较低的目标链长度(100 或 200 个单元)下,对主聚合物链长和主链分散性的控制差异相对较小。然而,ATRP 在 500 个单位的较长主链长度下提供了更好的受控聚合物。RAFT 和 ATRP 网络都比它们的传统自由基类似物溶胀到更大程度,ATRP 在更长的主链长度和更低的交联密度下提供更高的溶胀率。流变分析表明两种材料相似,尽管 RAFT 提供了具有更高弹性模量的材料,这与 RAFT 中更高的转化率和更低的溶胶分数一致。总体而言,RAFT 和 ATRP 形成的材料在较低的链长下具有相似的特性,ATRP 似乎在更长的链长下产生稍微更好的特性。RAFT 和 ATRP 中的控制可能是通过可溶性组分,包括 ATRP 中的小分子催化剂和 RAFT 中的可溶性聚合物部分(溶胶)。
更新日期:2021-09-28
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