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Rubber-like materials are widely used in mechanical systems. Schallamach waves appear in friction process due to their small elastic modulus and relatively large surface adhesion energy, which may cause some negative influences, such as additional vibration and singular wear. In-depth researches into the characteristics and mechanism of Schallamach waves are of great significance to development and application of rubber-like materials. Therefore, the nucleation and propagation law of Schallamach waves are investigated by using in-situ experiments and 3D finite element simulation method. Results indicate that small wrinkles appear firstly at the edges of contact regions. Here, the small wrinkles propagate towards the centers of the contact regions in a spiral manner, which is analyzed by using elastic theory. The first Schallamch wave forms on the sides of the contact region, while the subsequent waves nucleate at the front of the contact region. Then, In-situ experiments are carried out to study the influences of materials ratios and sliding velocity on the behaviors of Schallamach waves. Based on the finite element model, analysis results reveal the law of propagation speed, wave length and wave amplitude of Schallamach waves, and the relationship between contact area and force (frictional and vertical force). There is basically no sliding exiting in the contact interface during friction process, and in some extent the Schallamach waves play a lubricating role.

The decomposition of bisphenol A diglycidyl ether/alicyclic amine hardened networks in near-critical water was studied in this paper. It is possible to decompose thermosetting epoxy resin completely at 260 °C for 1 h with 1 g/5 ml feedstock ratio. The decomposition rate of epoxy resin increased with an increase in reaction temperature. The decrease in sample size led to higher decomposition rate, and the catalysts NH4Cl and H2SO4 had the higher positive effect on the decomposition rate. Thermogravimetry analysis (TGA) showed that thermal decomposition was not the primary factor for the collapse of networks in the temperature range studied. Gas Chromatography-Mass Spectrometry (GC-MS) showed the main components of the soluble decomposed compounds were bisphenol A, hydroxybenzene, olefin and ketone compounds and their content varied during the reaction. The hydrolysis of ether bond was regarded as the key factor in the process of decomposition reaction of bisphenol A diglycidyl ether/alicyclic amine hardened networks.

In this paper, a method of chemical recycling of thermosetting epoxy composite was discussed. Water was used to be reaction medium and the decomposition of carbon fibre reinforced epoxy composites was studied. Experiments were devised in order to identify the significant process parameters that affect fibre reinforced composite recovery potential including temperature, time, catalyst, feedstock, and pressure. Experiments were performed in a batch-type reactor without stirring. Under the condition that the temperature was 260 °C and the ratio of resin and water was 1:5 g/mL, the decomposition rate could reach 100 wt.% and the carbon fibres were obtained. The results from the Scanning Electron Microscopy (SEM) and Atomic Force Microscope (AFM) measurements showed that the fibres were clean and no cracks or defects were found. The average tensile strength of the reclaimed fibres was about 98.2% than that of the virgin fibres.

Chemical degradation of aramid/epoxy composites to the recycle of aramid fibers is presented in this article. 1,2,3,4-Tetrahydronaphthalene served as the main solvent decomposes the epoxy matrix and the virgin fibers are released under different decomposition conditions. The influence of reaction time, temperature, and feedstock ratio on the decomposition rate is investigated to ascertain the optimum condition of this recycle process. Gas chromatography mass spectrometry (GC-MS), single fiber tensile strength, and scanning electron microscope (SEM) are used to characterize the recycled fibers respectively, illustrating that aramid/epoxy composites can be decomposed successfully with this chemical method on the experimental condition. The hydrogenative mechanism of epoxy resin is also discussed tentatively according to the experimental result.

The cationic photoinitiator S,S-dialkyl-S-(3,5-dimethyl-4-hydroxyphenyl) sulfonium (called 4HPS simply) was synthesized in this article. The synthesis was proved successfully through FT-IR spectrum, 1H-NMR, and elemental analysis. The cure kinetics of photoinitiator/ ZH92-21 were studied through FT-IR spectrum combined with a high pressure mercury lamp. The concentrations of residual epoxy group, curing rate Rp and kinetics of polymerize termination were discussed. The results showed that the cure termination reaction of HPS photoinitiator/ZH92-21 was diradical-termination.

This study reports the method of recovery of glass fibers from glass/epoxy composites through the solvent method. It is possible to decompose epoxy resin with a yield of more than 99 wt% soluble products in a nitric acid solution (8 M) at 90 C for 5 h. The decomposition rate of epoxy resin increases with an increase in temperature and concentration of acid solution. The glass fibers can be recovered with very little contamination and they have a tensile strength reduction of 3.5% under decomposition conditions of T = 70°C, t = 250 h, C = 6 M and α= 6 g/100 mL. These fibers can be used as reinforcement to prepare new composites. The interlaminar shear strength (ILSS) of recovered short fiber-reinforced composites produce strength reductions of only 2.5% compared with pristine composites.