Ethylene Norbornene Copolymers (ENCs) belong to the Cyclic Olefin Copolymers (COC) family and are used in numerous industrial fields. The goal of this paper is to compare the behavior under electron beam radiation of three grades of ENCs. Several radiation doses have been tested: 25 kGy to simulate sterilization dose and higher doses (75 and 150 kGy) to emphasize the electron beam effect on polymer ageing.

By using Triple Detection (Refractometer/Laser Scattering/Viscometer) Size-Exclusion Chromatography, we wanted to study more accurately the evolution of ENCs under radiation than the previous studies available. Thanks to Triple detection, molecular weights were calculated without being dependent of calibration standards, branching was evidenced as the major effect of electron beams on those materials over a dose of 25 kGy, and long chain branching and branching chains frequencies were also calculated.

This study focuses on the effect of additive concentration and norbornene (NB) content and a trend has merged: for a same NB content, the higher the phenolic antioxidant concentration, the less crosslinked was the copolymer with the dose. By increasing NB content, radiation effects were minimized.

乙烯降冰片烯共聚物（ENC）属于环烯烃共聚物（COC）系列，并在许多工业领域中使用。本文的目的是比较三种等级的ENC在电子束辐射下的行为。已测试了几种辐射剂量：模拟灭菌剂量为25 kGy，并强调电子束对聚合物老化的更高剂量（75和150 kGy）。

通过使用三重检测（折光仪/激光散射/粘度计）尺寸排阻色谱法，我们希望比以前的研究更准确地研究辐射下ENC的演化。多亏了三重检测，分子量的计算不受校准标准的影响，支化被证明是电子束在剂量超过25 kGy时对这些材料的主要影响，并且还计算了长链支化和支链频率。

这项研究的重点是添加剂浓度和降冰片烯（NB）含量的影响，并且出现了一种趋势：对于相同的NB含量，酚类抗氧化剂的浓度越高，共聚物的交联量就越少。通过增加NB含量，可将辐射效应降至最低。