Transport Properties of One-Step Compression Molded Epoxy Nanocomposite Foams

Temperature Rise of an Adhesive Particle-Reinforced Polymer during Fatigue Testing

Construction adhesives are usually polymers that have been modified to achieve specific properties so that they can be used under various loading conditions. An attempt was made to estimate the effect of fatigue loading on the temperature of an adhesive material by further physically modifying the basic adhesive composition used in the research. The temperature of the materials during the tests was recorded using a thermal imaging camera and a thermoelectric thermometer. For most materials tested at 20 Hz, an increase in the number of load cycles corresponded to an increase in the temperature of the samples. For a frequency of 30 Hz, after the temperature increased by a certain value, the temperature of the modified samples recorded with the thermal imaging camera decreased. Fatigue loading caused an increase of the temperature of all tested polymeric materials. Observation of the sample during testing with a thermal imaging camera allows a simple identification of the areas with the highest temperature and can be much more useful in practice than recording temperatures with a thermocouple thermometer, as thermocouples need to be properly positioned before testing.

Preparation and Characterization of Bio-oil Phenolic Foam Reinforced with Montmorillonite

Introducing bio-oil into phenolic foam (PF) can effectively improve the toughness of PF, but its flame retardant performance will be adversely affected and show a decrease. To offset the decrease in flame retardant performance, montmorillonite (MMT) can be added as a promising alternative to enhance the flame resistance of foams. The present work reported the effects of MMT on the chemical structure, morphological property, mechanical performance, flame resistance, and thermal stability of bio-oil phenolic foam (BPF). The Fourier transform infrared spectroscopy (FT-IR) result showed that the -OH group peaks shifted to a lower frequency after adding MMT, indicating strong hydrogen bonding between MMT and bio-oil phenolic resin (BPR) molecular chains. Additionally, when a small content of MMT (2-4 wt %) was added in the foamed composites, the microcellular structures of bio-oil phenolic foam modified by MMT (MBPFs) were more uniform and compact than that of BPF. As a result, the best performance of MBPF was obtained with the addition of 4 wt % MMT, where compressive strength and limited oxygen index (LOI) increased by 31.0% and 33.2%, respectively, and the pulverization ratio decreased by 40.6% in comparison to BPF. These tests proved that MMT can blend well with bio-oil to effectively improve the flame resistance of PF while enhancing toughness.

Polymeric Foams

Advances in nanotechnology have boosted the development of more efficient materials, with emerging sectors (electronics, energy, aerospace, among others) demanding novel materials to fulfill the complex technical requirements of their products [...].