The Synthetization and Analysis of Dicyclopentadiene and Ethylidene-Norbornene Microcapsule Systems

Abstract

The activities of this paper were focused on an in-situ fabrication process for producing two self-healing systems containing dicyclopentadiene and 5-ethylidene-2-norbornene monomers encapsulated in a urea-formaldehyde shell and integration methods applied in the epoxy matrix to analyse and compare the influences of their integration into the neat epoxy matrix. The self-healing systems were first synthesized according to a literature review, and subsequently, an optimization process was conducted for the fabrication process. Neat epoxy specimens were fabricated as reference specimens and subjected to flexural tests. Several integration methods for incorporating the self-healing systems into the epoxy resin were investigated. The optimal method presenting the best dispersion of the healing system was achieved by reducing the viscosity of the epoxy matrix with 10 vol % acetone solution, the addition of a microcapsule in the matrix, and homogenization at 60 °C at 100 rpm. Thermal analysis was performed in order to observe the mass loss obtained with an increasing temperature and phase changes for both poly-urea-formaldehyde (PUF)-dicyclopentadiene (DCPD) and melamine-urea-formaldehyde (MUF)-5-ethylidene-2-norbornene (ENB) systems. The thermogravimetric analysis performed for the PUF-DCPD system indicates a total loss of mass in the range of 30–500 °C of 72.604% and for the MUF-ENB system, indicates a total mass loss in the range of 30–500 °C of 74.093%. Three-point bending tests showed higher mechanical properties for PUF-DCPD (80%) than MUF-ENB (40%) compared to the neat epoxy systems. Numerical simulations were performed to obtain a better understanding of the microcapsule behavior when embedded in an epoxy matrix.

A Microvascular System Self-Healing Approach on Polymeric Composite Materials

“…Also, as seen in the previous work performed by the authors [ 11 , 12 ], even though the microencapsulation of healing agents leads to an 80–85% recovery of mechanical properties, the integration of microcapsules within the matrix and the composite material acts as an induced damage and thus reduces the mechanical properties of the specimen, as compared to the reference ones. This is mainly due to the microcapsule dimensions and volume used, and the fact that after breakage, the microcapsule shells are left within the material, further acting as a stress concentrator for other mechanical loads to which the structure can be subjected to.…”

Evaluation of Dispersion Methods and Mechanical Behaviour of Glass Fibre Composites with Embedded Self-Healing Systems

“…As concluded in [ 23 ], a homogenous dispersion by magnetic stirring was found at a speed of 100 rpm and a temperature of 60 °C using an IKA C-MAG MS 10 (Sigma-Aldrich Chemie GmbH, Taufkirchen, Germany) magnetic stirrer with ETS-D6 sensor.…”

“…As the PUF-DCPD and MUF-ENB microcapsules batch were the same as in [ 23 ] and kept in sealed flasks for several months, a Fourier transform infrared (FT-IR) analysis was required to validate the presence of the core material. The analysis was performed on a Bruker VERTEX 70 (Bruker Optik GmbH, Leipzig, Germany) instrument employing 32 scans in the range of 400–4000 cm −1 and equipped with attenuated total reflection (ATR) using a Ge crystal.…”

New Technology for Production of Dicyclopentadiene and Methyl-Dicyklopentadiene

“…Copolymers with cycloolefins [14] are amorphous transparent polymers similar to polycarbonates and polymethyl methacrylate. Cyclic olefin copolymers are produced by the copolymerization of ethylene with a cyclic olefin monomer such as norbornene [15], dihydro DCPD, phenyl norbornene and tetracyclododecene [16,17], while Ziegler-Natta and metallocene catalysts are used in the polymerization processes. COC properties are low density, having excellent transparency, low water capillarity, chemical resistance, insulating properties and good processability.…”