Phenolic Resins

New class of reactive novolac: synthesis of bisphenol A-based novolac with methylol groups

“…The 13 (Figure 3). 1,33,35,36 These results confirmed that 2 contains arylene-methylene units, as shown in Scheme 1; moreover, some repeating units possessed acetoxymethyl moieties, which were formed by the condensation of acetic acid and methylol moieties, as described in our previous report. 33 Reactive novolac with a methylol group (3)…”

“…A volume of 1 mol l À1 KOH aqueous (2.0 ml) was added to a solution of 2 (0.28 g) in THF (3 ml), and the mixture was stirred at ambient temperature for 72 h. The mixture was poured into methanol (100 ml) to obtain the desired polymer (3). 1 Cure reaction between 3 and 4. The typical procedure for the cure reaction of 3 and 4 is as follows: 3 and 4 were dissolved in THF, and the solution was stirred for 1 h. The mixture was heated at 130 1C for several hours to vaporize solvent and water, and to carry out the cure reaction.…”

“…1 The product obtained was washed repeatedly with THF to obtain the insoluble resin (5). This insoluble product appeared to be the hardened phenolic resins of 4 cured by 3; however, there was a possibility that polymer 3 was cured itself, or 4 and 3 both cured each other.…”

“…'Novolacs' are the first synthetic resins to be prepared by acidcatalyzed addition-condensation of phenol with formaldehyde 1 and have already been used in practical application. These resins have interesting properties that make them suitable for industrial use, such as thermostability and mechanical strength.…”

“…1 As compared with novolacs, the resol resins have a number of methylol groups, which are introduced by the addition reaction of formaldehyde and phenol, and these groups react with electron-rich aromatic rings in the presence of heat or acids; consequently, resol resins are called thermosetting or reactive resins. [18][19][20][21] Resol resins are suitable for use as polymer additives, crosslinking agents and so on However, the architecture of their main chains is such that it contains both Ph-CH 2 -Ph and Ph-CH 2 -O-CH 2 -Ph units.…”