UV-Cured Poly(Ethylene Glycol) Diacrylate/Carbon Nanostructure Thin Films. Preparation, Characterization, and Electrical Properties

Abstract

Carbon nanoallotropes such as carbon nanotubes, graphene, and their derivatives have been combined with a plethora of polymers in the last years to develop new composite materials with interesting properties and applications. However, the area of photopolymer composites with carbon nanostructures has not been analogously explored. In the present article, we study the photopolymerization of poly(ethylene glycol)diacrylate (PEGDA) enriched with different carbon nanoallotropes like graphene, pristine and chemically modified carbon nanotubes (CNTs and fCNTs), and a hybrid of graphene and CNTs. The products were characterized by several microscopic and spectroscopic techniques and the electrical conductivity was studied as a function of the concentrations of carbon nanoallotropes. In general, stable thin films were produced with a concentration of carbon nanostructures up to 8.5%, although the addition of carbon nanostructures in PEGDA decreases the degree of photopolymerization, and PEDGA/carbon nanostructure composites showed electrical conductivity at a relatively low percentage.

UV-Light Curing of 3D Printing Inks from Vegetable Oils for Stereolithography

“…The mechanical properties of the resulting polymer materials are significantly dependent on the crosslinking density and hence on the conversion of functional groups [ 44 ]. Therefore, double bond conversion rate (DBC%) was calculated from the ratio of the intensity of the peak at 810 cm −1 related (C=C) groups against the intensity of the peak at 1361 cm −1 corresponding to (COO − ) groups, that is, unaffected by the photocrosslinking reaction, before and after the UV exposure at given time, using the Equation (1) [ 44 , 45 ]: DBC% = (1 − (A t /A ra )/(A 0 /A rb )) × 100%, where A t and A 0 —absorption intensities of the peak of (C=C) before and after UV-crosslinking and A rb and A ra —absorption intensities of the peak of (COO - ) before and after UV-crosslinking. Figure 3 depicts the variation of DBC% with curing time at different TPO loading, and the obtained curves confirm that the addition of polyfunctional comonomers increases the conversion degree by means of about 10%, as the values of DBC% obtained for M-AESO are higher than those obtained for neat AESO.…”

“…The mechanical properties of the resulting polymer materials are significantly dependent on the crosslinking density and hence on the conversion of functional groups [44]. Therefore, double bond conversion rate (DBC%) was calculated from the ratio of the intensity of the peak at 810 cm −1 related (C=C) groups against the intensity of the peak at 1361 cm −1 corresponding to (COO − ) groups, that is, unaffected by the photocrosslinking reaction, before and after the UV exposure at given time, using the Equation (1) [44,45]: DBC% = (1 − (A t /A ra )/(A 0 /A rb )) × 100%,…”

Thermomechanical Properties of Carbon Nanocomposites PEGDA Photopolymers

“…The mass percentage of the reinforced nanocomposites was selected to be between 1.5 and 8.5% ( w / w ), taking into consideration their conductive behavior, as was recently presented [ 23 ]. The percentage of 1.5% w / w was selected as the lower percentage of the fillers, since this was the lowest ratio that surface electrical conductivity was recorded as in the composites.…”

“…At this percentage, all samples were conductive and created stand-alone solid structures. At a higher percentage of the filler, very fragile and unstable structures were formed [ 23 ]. An intermediate percentage was included for better understanding of the behavior of the reinforced samples.…”

“…In a previous work, we have used graphene (G), multiwalled carbon nanotubes (MWNTs), and a hybrid of MWNTs and graphene 70/30 in mass ratio (Hyb) as nanofillers of the UV-curable resin, poly (ethylene glycol) diacrylate (PEGDA), to study the influence of reinforcement on the electrical properties of the nanocomposites [ 23 ]. In this article, we examine the thermomechanical properties of the same nanocomposites, denoted as PEGDA/G, PEGDA/M, PEGDA/Hyb, respectively.…”