Synthesis and thermal characterization of chemically modified phenolic resins
Synthesis and thermal characterization of chemically modified phenolic resins
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化学改性酚醛树脂的合成及热表征
DOI：
10.1002/app.1994.070540403
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发表时间：
1994
影响因子：
3
通讯作者：
C. Pillai
中科院分区：
文献类型：
--
作者：
R. Antony;C. Pillai
通过在单体阶段引入阻燃元素如磷和溴，然后与甲醛或三甲基四胺（HMTA）缩合，制备具有改善/改变的热稳定性和阻燃性的酚醛树脂。制备了一苯基磷酸（MPPA）、一苯基磷酸甲醛树脂（MPPAF）、溴化苯酚甲醛树脂（BrPF）和2，4，6-三溴苯基磷酸甲醛树脂（BrMPPAF），并对其进行了表征。用热重分析和氧指数评价了聚合物的热稳定性和燃烧性能，并与酚醛树脂（PF）和磷酸化酚醛树脂（PPF）进行了比较。热重分析（在空气中）的MPPAF表现出增强的热稳定性（焦炭产率66%）比PF（焦炭产率52%）和PPF（焦炭产率58%），表明磷赋予PF的耐热氧化性的作用。然而，溴的掺入导致PF的热稳定性意外降低（炭产率：BrPF，2%和BrMPPAF，26%）。磷和溴被发现提高PF（固化）的LOI值从35到50，48，和56，分别为MPPAF，BrPF，和BrMPAFF。这些树脂的LOI值与它们的炭产率的比较表明，在热分解过程中，磷和溴操作的气相机制的凝聚相机制。John Wiley & Sons，Inc.
Phenolic resins with improved/altered thermal stability and flame retardancy were prepared by introducing flame retardant elements such as phosphorus and bromine at the monomer stage, followed by condensation with formaldehyde or hexamethylene tetramine (HMTA). Thus, monophenyl phosphoric acid (MPPA), monophenyl phosphoric acid–formaldehyde resin (MPPAF), brominated phenol–formaldehyde resin (BrPF) and 2,4,6-tribromophenyl-phosphoric acid–formaldehyde resin (BrMPPAF) were prepared and characterised. Thermal stability and flammability of these polymers were evaluated by TGA and LOI respectively and compared with those of phenol–formaldehyde resin (PF) and phosphorylated phenol–formaldehyde resin (PPF). The TGA (in air) of MPPAF showed enhanced thermal stability (char yield 66%) over that of PF (char yield 52%) and PPF (char yield 58%) indicating the role of phosphorus in imparting thermo-oxidative resistance to PF. The enhancement is better when phosphorus is introduced at the monomer stage. The incorporation of bromine, however, brought about an unexpected reduction in the thermal stability of PF (char yield: BrPF, 2% and BrMPPAF, 26%). Both phosphorus and bromine are found to enhance the LOI values of PF (cured) from 35 to 50, 48, and 56, respectively, for MPPAF, BrPF, and BrMPAFF. A comparison of LOI values of these resins with their char yield suggests a condensed phase mechanism for phosphorus and vapor phase mechanism for bromine operating during thermal decomposition. © 1994 John Wiley & Sons, Inc.