Effects of network structures on the tensile toughness of copper-catalyzed azide-alkyne cycloaddition (CuAAC)-based photopolymers.
Effects of network structures on the tensile toughness of copper-catalyzed azide-alkyne cycloaddition (CuAAC)-based photopolymers.
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DOI：
10.1021/acs.macromol.0c02455
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发表时间：
2021-01-26
期刊：
影响因子：
5.5
通讯作者：
Bowman CN
中科院分区：
文献类型：
--
作者：
Song HB;Sowan N;Baranek A;Sinha J;Cook WD;Bowman CN
在本研究中，利用光引发的铜催化叠氮化-炔环加成(CuAAC)聚合来形成结构多样的玻璃聚合物网络。利用单体主链刚性(例如，具有不同主链长度的环基或脂肪基团)和反应性官能团密度(例如，四、三、双和单功能叠氮化物和炔基单体)的系统变化来提供易于裁剪的网络结构，其具有变化超过20倍的交联度密度(从橡胶模数估计)。所有八个所得到的网络结构的玻璃化转变温度(Tg)在50到80°C之间，拉伸韧性在28到61 MJ m−3之间。屈服应力和断裂伸长率(广义地定义为强度和延伸率，分别建立了三氮唑网络的玻璃化转变温度和橡胶模数。当柔性二炔单体(炔烃间碳间距为5)被引入到由三炔和叠氮单体组成的网络中时，断裂伸长率从166%提高到300%，而屈服应力从36 Mpa降低到23 Mpa。此外，通过在网络中加入单官能团叠氮化物作为链端，聚合物的延展性也有所不同--用更灵活的单叠氮化物取代空间受阻的硬质单叠氮化物，将断裂伸长率从24%提高到185%，拉伸韧性从6 MJ m−3增加到28 MJ m MJ 3。
In the present study, the photo-initiated copper-catalyzed azide-alkyne cycloaddition (CuAAC) polymerization was utilized to form structurally diverse glassy polymer networks. Systematic alterations in the monomer backbone rigidity (e.g., cyclic or aliphatic groups with a different length of backbone) and the reactive functional group density (e.g., tetra-, tri-, di-, and mono-functional azide and alkyne monomers) were used to provide readily tailorable network structures with crosslink densities (estimated from the rubbery modulus) varying by a factor of over 20. All eight of the resultant networks exhibited glass transition temperatures (Tg) between 50 and 80 °C with tensile toughness ranging from 28 to 61 MJ m−3. A nearly linear dependence of yield stress and elongation at break (broadly defined as strength and ductility, respectively) on the Tg and rubbery modulus was established in these triazole networks. When a flexible di-alkyne monomer (5 carbon spacing between alkynes) was incorporated in a network composed of a tri-alkyne and di-azide monomer, the elongation at break was improved from 166 to 300 %, while the yield stress was reduced from 36 to 23 MPa. Additionally, the polymer ductility was also varied by incorporating mono-functional azides as chain ends in the network - replacing a sterically hindered stiff mono-azide with a more flexible mono-azide increased the elongation at break from 24 to 185 % and the tensile toughness from 6 to 28 MJ m−3.
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影响因子：
4.6
作者：
Alzahrani AA;Saed M;Yakacki CM;Song HB;Sowan N;Walston JJ;Shah PK;McBride MK;Stansbury JW;Bowman CN
通讯作者：
Bowman CN
影响因子：
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影响因子：
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作者：
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通讯作者：
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作者：
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