Dielectric behavior of a rubber‐toughened epoxy resin

Abstract

Engineering, Vim Diotisalvi 2,561 00 h a , Italy synopsis The dielectric behavior of amine-terminated butadiene acrylonitriie rubber/DGEBA epoxy resin blenda of ditrerent formulations has been studied in the temperature range -12&16O0C at 10 IJIZ. h indicatd by the constancy of the giasa transition temvatures of the two components, the degree of segmeutal mixing wan vary low or nil. irrespective of cure schedulea The h d t y of the a-relaxation of the rubber wan much leee than that predicted by the Simple series model (lower bound). Thia hm been attributed to incomplete phase separation at gelation. Meaeurementa cnrried out with a nonreactive rubber support this conclusion. Part of the rubber remain6 mol&ly dieperaed within the gh?ay matrix, thus contributing to the modification of the maehrnical p r o m of epoxy resina brought about by reactive rubbers.

Dielectric analysis of the linear polymerization of an epoxy resin

“…The spectrum of the neat resin showed two relaxation processes, which can be classified36–38 as main (or structural) (α) and secondary (γ), respectively, while the unreacted mixture exhibited a single broad relaxation, substantially different from that of the neat resin at the same temperature (25 °C); see Fig 1. The relaxation of the amine, the viscosity of which was much lower than that of the resin, was located at much higher frequency, outside our experimental window.…”

Miscibilization of low molecular weight functionalized polyethylenes in epoxy resins: Part 2. Effects of curing on morphological features and mechanical properties

“…At higher curing temperatures, therefore, a less dense network can be formed inside the hardened resin, which in turn implies a lower degree of cure with subsequent reduced Tg values and brittleness. The occurrence of a less dense network at high curing temperature has been also explained by other authors with the volatilization of the hardener, 51,52 though some researchers did not observe any weight loss during polymerization at 120ЊC, 52,53 -55 and/or the oxidation of the hardener, as indicated by the progressive darkening of castings. 47 In another study the variation of the molecular 56 weight between cross-links of a DGEBA resin (i.e., Mc) was related to the curing temperature.…”

Flexural, impact, rheological and physical characterizations of POM reinforced by carbon nanotubes and paraffin oil

“…At PC 1 and PC 2 , significant increasing occurred ~23 and ~29% respectively, because of the increasing of CNT amount leading to more coalescence between CNT nanoparticles and POM; thus, impact strength increases. In addition, CNT had impact strength more than POM and, also, increased energy absorption during the impact process . Finally, impact strength of PC 2 was decreased because of CNT agglomeration …”

“…In addition, CNT had impact strength more than POM and, also, increased energy absorption during the impact process. [27] Finally, impact strength of PC 2 was decreased because of CNT agglomeration. [28] Optical microscopy also was used to inspect the impact damage surfaces for PC 2 and PC 3 .…”