On the chemistry, behavior, and cure acceleration of phenol–formaldehyde resins under very alkaline conditions

Pizzi, A.; Stephanou, A.

doi:10.1002/app.1993.070491212

Cited by 84 publications

(75 citation statements)

References 24 publications

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“…An example of this is shown in Figure 4(a) and (b), showing the first-derivate peaks of a less-polymerized PF resin (and of lower molar ratio of P : F ϭ 1 : 1.8) by itself and on addition of an accelerator, such as glycerol triacetate. 7 The entanglement and crosslinking peaks occur later for the less-polymerized PF resin alone (Table I) than in the case of the more advanced PF resins discussed above. The low level of polymerization PF resin to which the accelerator has been added develops the entanglement peak (but not the crosslinking peak) at a slightly lower temperature than the same resin without accelerator.…”

Section: Discussionmentioning

confidence: 95%

Crosslinked and entanglement networks in thermomechanical analysis of polycondensation resins

Garcı́a¹,

Pizzi²

1998

J. Appl. Polym. Sci.

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Thermomechanical analysis (TMA) tests on joints bonded with synthetic phenol-formaldehyde (PF) resins have shown that, frequently, the joint increase in modulus does not proceed in a single step but in 2 steps, yielding an increase of the modulus first-derivate curve presenting 2 peaks rather than a single peak. This behavior has been found to be due to the initial growth of the polycondensation polymer, leading first to linear polymers of critical length for the formation of entanglement networks. Two modulus steps and 2 first-derivate peaks then occur, with the first due to the formation of linear polymers entanglement networks, and the second due to covalent crosslinked networks. The faster the reaction of phenolic monomers with formaldehyde, or the higher the reactivity of a PF resin, the earlier and at lower temperature the entanglement network occurs; more important is its modulus value in relation to the final, crosslinked resin modulus. The accepted methods of calculating the gel point and gel temperature of a polycondensation resin or from the single peak of the first derivate of the modulus increase curve or from the start of the uprise of the modulus increase curve is still acceptable in resins in which the entanglement effect is small or it is not present. In resin systems in which the entanglement effect, instead, is of importance, the question of what is the gel point in such systems had to be addressed, and gel temperature and gel point must be obtained from the modulus and its firstderivate curve in a different manner, which is presented.

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Section: Discussionmentioning

confidence: 95%

Crosslinked and entanglement networks in thermomechanical analysis of polycondensation resins

Garcı́a¹,

Pizzi²

1998

J. Appl. Polym. Sci.

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“…Higher carbonates and cyclic aliphatic carbonates are used in the formulation of flavors and fragrances [484][485][486], and certain cyclic aromatic carbonates for thermal recording materials [487]. Cyclic carbonates are also used as reactive thinners in RIM polyurethanes [488], as activators in polyurethane coatings [489], epoxy [490], [491] and phenol -formaldehyde resins [492], and in silicate-based binders for molding sand [493]. Further applications are described in [466-469, 494, 495].…”

Section: Direct Usesmentioning

confidence: 99%

Carbonic Esters

Buysch

2000

Ullmann's Encyclopedia of Industrial Chemistry

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The article contains sections titled: 1. Introduction 2. Properties 3. Production 3.1. Phosgenation of Alcohols 3.2. Phosgenation of Phenols 3.3. Oxidative Carbonylation of Alcohols 3.4. Oxidative Carbonylation of Phenols 3.5. Oxidative Carbonylation of Alcohols with NO x 3.6. Carbonic Esters from Oxalic Esters 3.7. Electrochemical Oxidative Carbonylation of Alcohols 3.8. Reaction of CO 2 with Oxiranes 3.9. Reactions of Alcohols with Urea 3.10. Reaction of Phenols with Urea 3.11. Miscellaneous Reactions of CO 2 to Form Carbonates 3.12. Transesterification 3.13. Cyclic Carbonic Esters 4. Environmental Protection and Toxicology 5. Quality Specifications 6. Analysis 7. Storage and Transportation 8. Uses 8.1. Direct Uses 8.2. Use for Chemical Synthesis 9. Economic Aspects

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“…Resol PF resin is prepared using a formaldehyde-to-phenol molar ratio above 1 and an alkali as catalyzer, which is a common material for activated carbon (Pizzi and Stephanou 1993). There are many activation methods to activate carbonized PF resin, but chemical methods still have a wide range of applications in industrial production.…”

Section: Introductionmentioning

confidence: 99%