Modified phenol–formaldehyde novolac resins: Synthesis and thermal oxidative degradation

Abstract

SynopsisNew phenolic resins containing titanium and silicon in the main polymer structure were synthesized and some of their properties were investigated. Titanium and silicon contents of the polymers ranged from 2 to 13% titanium and from 2 to 5% silicon. These polymers became insoluble and infusible as the titanium and silicon contents of the products were increased. IR spectra of these modified resins were presented. The thermal oxidative degradations of the phenolic resins modified with titanium and silicon were also investigated using thermogravimetry and differential thermal analysis. Titanium and silicon-modified polymers showed considerably lower weight changes as compared with those of unmodified or titanium-modified polymers, but the rate of the last oxidative degradation increased and the final degradation temperature decreased with increasing titanium concentration. The best results for the thermal resistance was found t o be 2% 5 Ti 5 6% and Si 2-5%.

Modification of high ortho novolac resin with diacids to improve its mechanical properties

“…The FT‐IR spectra of the N and MN were presented in Figures 1 and 2. These spectra indicate the reduction of the intensity of the absorption band observed at 1409–1315 cm −1 (max at 1371 cm −1 )34 due to the hydroxyl groups of methylol groups in the high ortho novolac resin structure and this absorption band has also shifted to about 1374, 1366, 1363, and 1359 cm −1 depending on the type and amount of the diacid. The changes in the above mentioned bands can be attributed to the change in the methylol content of the novolac resin due to the modification reactions.…”

“…In several previous articles,34, 42 the thermal oxidative degradation of phenolic resins was reported and it was mentioned that the phenolic resins mainly degrade in three recognizable steps: preliminary, middle, and a final oxidative degradation. All MN that are produced in this study by the modification reaction with diacids exhibit more or less the same thermal oxidative degradation stability.…”

“…Polycondensation reaction of FA and P was carried out according to known procedure9–11, 34 using 0.187 mole ratio of FA/P and at pH = 7. The reaction system was a 500‐mL four‐necked conventional glass reaction kettle equipped with a mechanical stirrer, heating mantle, reflux condenser, temperature control system, and N 2 inlet.…”

Preparation, characterization and thermal properties of titanium- and silicon-modified novolac resins

“…[4][5][6] Boron-containing compounds have also been extensively introduced into the phenolic resins by many researchers, 7,8 which exhibited an outstanding performance of flame retardancy and thermo-oxidative resistance, which was attributed in the formation of nonpenetrable glass coatings during the thermal degradation. 8 As to multiple elements co-modified phenolic resins, Tugtepe and Ozgumus 9 have reported titanium-and silicon-modified novolac resins prepared by a two-step route showing considerably lower weight change during the thermal degradation. To the author's knowledge, in this work, titanium-and silicon-containing novolac resins were prepared in our laboratory by a one-step reaction of novolac resin with organo-titanium polysiloxane (OTPS), which is a new route that has not yet been reported elsewhere.…”

Kinetic Study of Titanium-Modified Phenolic Resin Curing Process by DSC Analysis

“…For example, structure modification and blending with other compounds [1][2][3] . It is reported that through modification of their structure with introduction of some elements, such as boron, phosphorus, silicon [4][5][6][7] , molybdenum, titanium, zirconium [8][9][10][11] , can improve thermal properties of phenolic resin.…”