Evaluation of electron beam‐induced crosslinking of poly(ε‐caprolactone)—Effect of elevated temperatures

Abstract

The effect of elevated temperatures (40, 80, and 170 °C) on the electron beam (EB)‐induced crosslinking and degradation of poly(ε‐caprolactone) (PCL) in nitrogen atmosphere without adding crosslinking agents has been investigated. The increased mass average molecular mass of EB modified masticated PCL (mPCL) samples were measured by size exclusion chromatography. The sol–gel investigation showed that mPCL tended to dominating crosslinking at a temperature of 170 °C. At this temperature, the maximum gel content of 56% was observed for an EB treatment with a dose of 100 kGy. In addition, the ratio of chain scission density to density of crosslinked units amounted to 0.25. The dynamic rheological test demonstrated that EB treatment at 170 °C led to the most remarkable elasticity enhancement behavior with enhanced viscosity, modulus, and decreased loss factor (tan δ). The occurrence of branching structure was evidently detected by van Gurp–Palmen plot in combination with the Cole–Cole plot for dose values ≤50 kGy. Less δ and a broadened relaxation process can be observed due to the introduction of some branched structures into mPCL. The results of enhanced molar mass and gel content analysis were confirmed by the dynamic rheological measurements. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47866.

Melt spinning of PLA/PCL blends modified with electron induced reactive processing

“…The G values of chain scission (G s ) and crosslinking (G x ) of the neat PLA and PCL were investigated at different temperatures in our previous work. 16,17 It was found that the ratio of G s /G x was 3.2 and 0.5 for PLA and PCL at 170 C, respectively. It points out that the neat PLA tends to degradation and PCL is more prone to crosslinking during electron beam induced reactive processing.…”

“…However, we found that EB induced crosslinking of PLA and PCL can be obtained at 170 C without any use of crosslinking agents. 16,17 Therefore, in this work, EIReP is applied to modify the structure and properties of PLA/PCL blends without using any chemical additives. Subsequently, the spinnability of EIReP modified PLA/PCL blends was investigated by melt spinning.…”

The effects of electron beam radiation on material properties and degradation of commercial PBAT/PLA blend

“…16,28,29 Meanwhile, if the degradation process of PLA will dominate in the system, the M n will significantly decrease. According to the literature, in the case of crosslinked structure formation, the M n and Đ should increase with increasing radiation dose.…”

“…According to the literature, in the case of crosslinked structure formation, the M n and Đ should increase with increasing radiation dose. 16,28,29 Meanwhile, if the degradation process of PLA will dominate in the system, the M n will significantly decrease. 30 As evidenced by the data presented in Table I, the molecular weight of the irradiated and nonirradiated Ecovio films were very similar.…”

Synthesis and Assessment of AMPS-Based Copolymers Prepared via Electron-Beam Irradiation for Ionic Conductive Hydrogels

“…Due to these advantages, E-beams have been applied to various materials from reactive monomers to various water-soluble polymers [19,20]. However, it is very difficult to analyse the structure of hydrogels because various active species are generated during the E-beam irradiation, which induces chain branching and crosslinking [21,22].…”