Radical photopolymerization of acrylate was carried out without a degassing process under conditions suitable for UV-curable coatings and UV-curable adhesives. We examined the differences in the resulting polymer structures obtained from the coating and adhesive by employing the same formulation. 2,2-Dimethoxy-2-phenylacetophenone was employed as a photoinitiator. The UV-curable coating yielded polymers terminated by either a hydroxyl group or a terminal carbonyl group as the main products. On the other hand, the UV-curable adhesive yielded a multitude of polymers that were terminated by disproportionation. In the latter case, some polymers underwent hydrogen abstraction from the polymer backbone, resulting in β-scission of the midchain radical to generate polymers with an α-substituted acryloyl group as the terminal group. We examined the differences between the resulting polymer structures in the cases of a coating and an adhesive employing the same formulation. The UV-curable coating yielded polymers terminated by either a hydroxyl group or a terminal carbonyl group as the main products, suggesting that bimolecular termination was strongly inhibited by oxygen. On the other hand, the UV-curable adhesive yielded a multitude of disproportionation products, whereas some polymers underwent hydrogen abstraction from the polymer backbone, resulting in β-scission of the midchain radical to generate polymers with an α-substituted acryloyl group.

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UV 固化条件对聚合物结构的影响：涂料和粘合剂之间的比较

在适用于紫外线固化涂料和紫外线固化粘合剂的条件下，丙烯酸酯的自由基光聚合无需脱气过程即可进行。我们通过使用相同的配方检查了从涂料和粘合剂中获得的聚合物结构的差异。2,2-二甲氧基-2-苯基苯乙酮用作光引发剂。UV 固化涂层产生的聚合物以羟基或末端羰基为主要产物。另一方面，紫外线固化粘合剂产生大量聚合物，这些聚合物因歧化而终止。在后一种情况下，一些聚合物从聚合物骨架中夺氢，导致中链自由基的 β 断裂，生成具有 α-取代丙烯酰基作为端基的聚合物。我们检查了在涂层和粘合剂采用相同配方的情况下所得聚合物结构之间的差异。UV 固化涂层产生的聚合物以羟基或末端羰基为主要产物，表明双分子终止受到氧的强烈抑制。另一方面，紫外光固化粘合剂产生大量歧化产物，而一些聚合物从聚合物主链上夺氢，导致中链自由基发生 β 断裂，生成具有 α-取代丙烯酰基的聚合物。UV 固化涂层产生的聚合物以羟基或末端羰基为主要产物，表明双分子终止受到氧的强烈抑制。另一方面，紫外线固化粘合剂产生大量歧化产物，而一些聚合物从聚合物主链中夺氢，导致中链自由基的 β 断裂，生成具有 α-取代丙烯酰基的聚合物。UV 固化涂层产生的聚合物以羟基或末端羰基为主要产物，表明双分子终止受到氧的强烈抑制。另一方面，紫外光固化粘合剂产生大量歧化产物，而一些聚合物从聚合物主链上夺氢，导致中链自由基发生 β 断裂，生成具有 α-取代丙烯酰基的聚合物。