Kinetic study of polysulfide‐acrylate click reaction by DEA and DMA

Abstract

The curing process of a polysulfide (PSF) with a triacrylate crosslinker in the presence of an amine catalyst at room temperature is a rapid Michael addition. This reaction was monitored by real‐time infrared spectrum (RTIR). The results of the RTIR show that the consumptions of thiol and acrylate are stoichiometric until 80% conversion, indicating the characteristics of a “click” reaction. Dielectric analyzer (DEA) and dynamic mechanical analyzer (DMA) were employed to investigate the curing kinetics from which the activation energies of this curing reaction were obtained and shown to correlate with each other. In addition, the influences of the types and amount of amine catalyst, the different molecular weights of PSFs, and the triacrylate crosslinkers were discussed. Copyright © 2011 John Wiley & Sons, Ltd.

Cure monitoring of CFRP composites by dynamic mechanical analyser

“…This rapid increase in storage modulus and the tanδ peak corresponded to the vitrification of the resinthe time in the curing process when the resin solidifies. Vitrification indicates that the cure temperature is approaching or equalling the glass transition temperature of the fullycured resin due to the transition from a rubbery to a glassy state [5,10]. However, vitrification does not necessarily indicate the end of the formation of the crosslink network.…”

“…Other techniques such as Fourier transformed infrared (FTIR) spectroscopy and rotating or oscillating rheometers can also be used to characterise the cure process of resins. The FTIR method consists of following the evolution of specific functional groups with time and temperature from which the degree-of-conversion of a functional 2 group can be estimated [3][4][5]. On the other hand, the variation of the resin viscosity is monitored using rheometers during the initial stage of the cure (prior to gelation) [6,7].…”

“…However, this technique is also suitable to monitor the cure development and the gelation and vitrification transitions in thermosets. Cure monitoring of liquid resins with a DMA is achieved using either an inert impregnation braid or tape made of glass fibres, or a cup and probe or shear piston system [5,[8][9][10]. The disadvantage with the former method is that low viscosity resins cannot be monitored without the risk of contaminating the oven and the drawback with the latter method is that the probe is trapped in the resin when gelation is reached; therefore information about the vitrification of the resin cannot be obtained.…”

“…Depending on the resin viscosity, the use of a thin nylon film enveloping the prepreg may be required in order to avoid the liquid resin from dripping inside the DMA oven [13]. Cure monitoring using the DMA highlighted the different transitions that a thermosetting resin encounters during the crosslinking reaction: the gelationfrom a liquid to a rubberand the vitrification from a rubber to a glass material [5,8,10,13,14]. The work presented in this paper focuses on assessing whether the use of a container device based on stainless steel pocket has an influence on the cure of a carbon/epoxy prepreg and an epoxy resin, which was monitored by dynamic mechanical analysis (DMA).…”

The preparation and physical properties of polysulfide-based elastomers through one-pot thiol-ene click reaction

“…These cross-linked elastomers derived from PSF oligomers have high resistance to UV radiation and the environment, exhibit good low-temperature properties, low water-vapour transmission, and resist solvents and chemicals. Our earlier works have also studied metal oxide or isocyanate cured polysulfide polymer [24][25][26] and explore kinetic analysis of polysulfide-acrylate click reaction by dielectric analyzer and dynamic mechanical analyzer [27]. Here, we successfully prepared polysulfide-based elastomers by reacting PSF oligomers with bisphenol-A diacrylate resin through one-pot thiol-Michael addition reaction, in which tris(dimethylaminomethyl)-phenol (DMP-30) was used as a catalyst.…”