Okamura Haruyuki, Yamagaki Masashi, Nakata Kyohei
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
Polymers (Basel). 2018 Dec 20;11(1):5. doi: 10.3390/polym11010005.
An analysis of the network structures in thiol-ene UV curing resins was carried out using reworkable resins composed of di(meth)acrylate monomers having tertiary ester linkages. The effect of the functionality of the thiols, the functional ratio of the thiol and ene functions, their conversions and curing atmosphere on the chain lengths was discussed. A mixture of (meth)acrylates, thiol compounds, a photoradical initiator, and a photoacid generator was cured by irradiation at 365 nm. The cured samples were degraded by heating after irradiation at 254 nm. Size exclusion chromatography (SEC) and ¹H NMR analyses of the degraded samples were carried out after the methylation. The crosslinking conditions strongly affected the network structures. The degraded samples have molecular weights between 250 and 2700. The molecular weights of the degraded resins increased with the functionality of the thiol compounds. The chain length dependence suggests that thiol compounds with a high functionality have a low reactivity due to steric hindrance. The chain lengths of the degraded networks were nearly proportional to the concentration of the (meth)acrylate monomers. The addition of reactive diluents enhanced the reactivity and increased the chain length.
使用由具有叔酯键的二（甲基）丙烯酸酯单体制成的可返工树脂，对硫醇-烯紫外光固化树脂中的网络结构进行了分析。讨论了硫醇的官能度、硫醇与烯官能团的官能比、它们的转化率以及固化气氛对链长的影响。（甲基）丙烯酸酯、硫醇化合物、光自由基引发剂和光酸产生剂的混合物通过365nm的辐照进行固化。固化后的样品在254nm辐照后通过加热进行降解。甲基化后对降解样品进行尺寸排阻色谱（SEC）和¹H NMR分析。交联条件对网络结构有很大影响。降解后的样品分子量在250至2700之间。降解树脂的分子量随着硫醇化合物的官能度增加而增加。链长依赖性表明，由于空间位阻，高官能度的硫醇化合物具有较低的反应活性。降解网络的链长几乎与（甲基）丙烯酸酯单体的浓度成正比。添加反应性稀释剂提高了反应活性并增加了链长。
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