六亚甲基四胺
固化(化学)
材料科学
甲醛
复合材料
苯酚
流变学
高分子化学
化学
化学工程
有机化学
工程类
作者
Mauro Milazzo,Angela Amoresano,Rossana Pasquino,Nino Grizzuti,Finizia Auriemma,Fabio De Stefano,Agustin Sin Xicola,V. Iodice,Claudio De Rosa
出处
期刊:Macromolecules
[American Chemical Society]
日期:2021-12-08
卷期号:54 (24): 11372-11383
被引量:4
标识
DOI:10.1021/acs.macromol.1c01598
摘要
The curing performance of a homogeneous set of different grades of novolac-type phenol–formaldehyde (PF) resins having different structures is analyzed. The PF resins have a statistical ortho/para substitution at aromatic rings and contain from 5 to 15 wt % hexamethylenetetramine (HMTA) as a hardener. Moreover, the different analyzed grades are PF resins differently modified by addition of boron/phosphorous compounds, or an acrylic rubber, or silicone and xylene/phenol copolymers, or introduction of aralkyl modifications. The curing behavior is compared with that of an unmodified PF resin in which the cross-linking agent (HMTA) is added into the molten polymer to guarantee a good dispersion according to the hexamine adduct phenolic (HAP) technology. The effect of the different modifications is probed by rheological measurements during curing under isothermal conditions. Under similar curing conditions, the modified resins show different curing performances and lower stiffness with respect to the unmodified Ph resin obtained by HAP technology. A method to quantify the curing performance is introduced and suggested based on two relevant parameters derived from rheological measurements, the “curing ratio” that indicates the efficiency to generate the thermal-induced three-dimensional network and a “maximum curing rate” that is related to the cross-linking reaction rate. The results allow classifying the resins as belonging to different classes, depending on the combination of the curing ratio and curing rate.
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