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One paper was published in Polymer Degradation and Stability

  Recently, one paper titled as “The effect of free dihydroxydiphenylmethanes on the thermal stability of novolac resin” by Ping Zhang et al. was published on Polymer Degradation and Stability. Zhang is a master candidate supervised by Prof. Xinli Jing. (Paper link to: DOI:S0141391019302666)

 

  In this paper, the dihydroxydiphenylmethane (DHDM) contents in several typical industrial novolac resins (NRs) were measured by liquid chromatography and gel permeation chromatography, and the effect of DHDM content on the viscosity, curing process, glass transition temperature (Tg) and thermal stability of NRs was investigated. The results showed that a significant reduction in viscosity and Tg was observed for the NRs with higher DHDM content. The existence of DHDMs reduced the gel point and crosslinking density of the cured NRs by hexamethylenetetramine, leading to a significant decrease in the 5% weight loss temperature, the maximum weight loss temperature, as well as the char yield at 800℃. Therefore, in addition to the free phenols, we should pay more attention to the DHDMs existed in the NRs. This study provides an important insight for NR manufacturers that the DHDM contents should be reduced through the proper control of process parameters to further expand their wider application scope.    

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