Is phenolic resin water soluble?
It was found that the modified epoxy phenolic resin could still dissolve in water after being heated at 120 oC for 10 min, and the solubility remained almost unchanged. But upon being heated at the temperature of 140 oC, the resin became completely insoluble in water.
Is phenol formaldehyde water soluble?
The water-soluble phenol-formaldehyde resin was synthesized by the technology of two-step base catalysis with NaOH and Ba(OH)2•8H2O composite catalyst. The movable gel prepared with this crosslinking agent and polyacrylamide has good stability and long shelf life through the performance evaluation experiment.
What happens when phenol reacts with formaldehyde?
One reacts phenol and formaldehyde directly to produce a thermosetting network polymer, while the other restricts the formaldehyde to produce a prepolymer known as novolac which can be moulded and then cured with the addition of more formaldehyde and heat.
How do you dissolve phenol-formaldehyde resin?
phenolic resin is a brittle polymers and have good thermal properties due to the presence of aromatic structure in their polymers chain, So in order to degradation with out using heat y using strong solution of sodium hydroxide.
How is phenolic resin made?
Phenolic resins are manufactured from phenol and formaldehyde. Reaction of phenol with less than equimolar proportions of formaldehyde under acidic conditions gives so-called novolac resins containing aromatic phenol units linked predominantly by methylene bridges.
How do you dissolve phenolic resin?
Ethanol or acetone is usually selected to be solvent for phenolic solution. However, our research indi- cated that by comparing to other solvents, methanol can increase curing rate and enhance crosslinking density of the phenolic resin.
What is phenol formaldehyde resin used for?
Phenol-formaldehyde resins make excellent wood adhesives for plywood and particleboard because they form chemical bonds with the phenol-like lignin component of wood. They are especially desirable for exterior plywood, owing to their good moisture resistance.
Is phenol formaldehyde resin toxic?
As a result of this screening assessment, the Government concluded that the 8 substances in the Phenol-formaldehyde Resins Group are not harmful to human health or to the environment at levels of exposure considered in the assessment.
What are the properties of phenol formaldehyde?
Properties of Phenolic Resins In addition, phenol formaldehyde resin properties include good thermal insulation, low density and excellent durability. They are easy to mold into a variety of shapes and complex contours, making them adaptable to custom equipment or environments.
How is phenol formaldehyde resin made?
phenol-formaldehyde resin, also called phenolic resin, any of a number of synthetic resins made by reacting phenol (an aromatic alcohol derived from benzene) with formaldehyde (a reactive gas derived from methane). The other method involves reacting formaldehyde with an excess of phenol, using an acid catalyst.
Does resin have formaldehyde?
Formaldehyde resin is a synthetic resin product made with formaldehyde as a base ingredient. This product is used in a wide variety of settings and industries, and is one of the oldest synthetic resins around. Phenols, melamine, urea, and aniline can all be used to make formaldehyde resin for various applications.
What is PF (phenol-formaldehyde)?
Phenol-formaldehyde (PF) is a thermosetting resin that is widely used in many fields. One of its important applications is as an adhesive for wood-based panels manufacturing.
Can lignin replace phenol in phenol-formaldehyde resin synthesis?
The modified lignin from these later methods could partially replace phenol in phenol-formaldehyde resin synthesis.
Is it possible to prepare phenol formaldehyde resin using alkaline rice straw lignin?
However, there has been little research published on the preparation and characterization of phenol formaldehyde resin using alkaline rice straw lignin.
What is the molar ratio of sodium hydroxide to formaldehyde?
The molar ratios of sodium hydroxide to phenol-modified alkaline lignin and the formaldehyde to phenol-modified alkaline lignin were from 1.0 to 1.4, and 1.8 to 2.6, respectively. The parameters used to characterize the modified phenol-formaldehyde resins were: free-formaldehyde, gel time, viscosity, pH, and solid content.