Cashew Oil-modified Phenolic Resin Foamed Material

In this paper, reaction and mechanism of the synthesis of the cashew nut shell liquid (CNSL) modified phenolic resin were studied. Particularly, the effect of mole ratio of phenol and formaldehyde, and the cashew nut shell liquid on the properties of the CNSL modified thermosetting phenolic resin as well as the curing process of modified phenolic resin and the mechanical properties of phenolic foam materials were also investigated.The FT-IR,13C-NMR,1H-NMR techniques were used to characterize the structure of CNSL modified phenolic resin. It showed that the reaction mechanism were similar with common phenolic resin. Then the properties of the CNSL modified thermosetting phenolic resin were studied. It was found that the performance of CNSL modified phenolic resin was excellent while the mole ratio of formaldehyde and phenol was 2, and the best adding amount of CNSL was 15%. The research also showed the incorporation manner of CNSL had little effect on the-CH2OH index of the modified resin.The isothermal DSC technique was used to evaluate the effect of the amount of the employment of CNSL on the curing behavior of the modified phenolic resin. It was found that the initial curing temperature and the curing activation energy decreased with the increased amount of CNSL, and the curing speed was lower than that of the common phenolic resin. The thermal degradation of the CNSL modified thermosetting phenolic resin was studied by TGA. It can be observed that there were three stages in thermal degradation and the amount of CNSL was associated with the thermal degradation behavior of phenolic resin.The performance of CNSL modified phenolic resin foam was investigated by measurement of the viscosity and pH of the modified phenolic resin. The foam exhibited an excellent performance when the viscosity was set at 3000 mpa.s plus and the pH was 3.0. It was also found that strength of foam increased by 23.8%, the flexural modulus was above 79% and weight loss increased by 20.5% when the adding amount of surface active agent, blowing agent and CNSL were 7%,6% and 10% as well as mixed acid was used as curing agent.