Preparation And Characterization Of Phenolic Resin/Organic Monmorillonlite And Its Application

Phenolic resin (PF) is one of the world's first industrialization synthetic resin products with the lower price and convenient synthesization. Phenolic resin is widely used to prepare the mold plastics, adhesives, ablative material due to its high mechanical strength, heat resistance, flame retardant, etc. However, the phenolic hydroxyl and methylene are easily oxidized resulting in poor heat resistance and oxidation resistance. The cured phenolic resin is brittle because of methylene-linked between the chain of the phenolic resin. Therefore, the research about the modified phenolic resin in order to improve its heat resistance and toughness becomes important issues.In this paper, the montmorillonites(MMTs) were respectively organically modified by hexadecyl trimethyl ammonium bromide (CTAB) and silane coupling agent KH-560 via CTAB ion-exchange method, KH-560 hydrolysis method and non-hydrolysis method. The structure of modified MMTs was characterized by fourier infrared spectrum (FTIR) and X-ray diffraction (XRD). The results showed that the layer spaces of the MMT modified by ion-exchange method (CTAB-MMT), KH-560 hydrolysis method (HS-MMT) and non-hydrolysis method (NHS-MMT) were 2.22nm,1.62nm and 1.77nm, when the modifier content got 50wt% of the MMT.Phenolic resin/organic montmorillonite (PF/OMMT) were prepared by melt-intercalation with the former three modified MMTs and the structures and thermal properties of the PF/OMMT nanocomposites were analyzed using XRD, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). TEM results showed that CTAB-MMT, HS-MMT, NHS-MMT formed intercalated structure, exfoliated-intercalated mixed structure and exfoliated structure. TG indicated that thermal property of PF could be enhanced by adding modified MMTs. Compared to the pure PF, the thermal decomposition temperatures of PF adding by CTAB-MMT, HS-MMT and NHS-MMT were enhanced 44.5℃,63.8℃and 82℃. The thermal performance of PF/OMMT nanocomposites and the MMT layers dispersion modified by KH-560 were better than PF/OMMT nanocomposites modified by CTAB due to the raction between epoxy group of KH-560 and the phenolic hydroxyl during the cure process which could enhanced the PF thermal performance and enlarged the MMT layer spaces. Moreover, the brake pads based on the former three PF/OMMT nanocomposites were prepared and the impact strength, rigidity and friction coefficient were also tested. The results illustrated that The friction and wear tests illustrated that the brake pad based on PF/OMMT had more stable friction coefficient and lower wear rate than that of the brake pad based on pure PF.The friction coefficient of brake pad based on PF/OMMT using KH-560 non-hydrolysis method was more stable than other two method due to the excellent thermal performance of PF/OMMT. It could be used as a high performance of frictional material.