Laboratories worldwide provide the high-tech environments that lab managers need to make groundbreaking discoveries and innovative solutions to the world’s most pressing problems. However, such work necessitates the use of high-quality lab tables and phenolic table top in each laboratory comprised of high-quality materials.
Choosing the right material for your lab equipment is crucial when choosing your laboratory tables, and phenolic resins have proven to be the preferred choice of lab managers worldwide.
In this article, we will provide you with some of the basics of phenolic resin, including what it is, how it is manufactured, and why it makes for a durable choice for all types of lab tables.
Continue reading to learn more about phenolic resin and how LabTech Supply Company can provide you with high-quality science lab equipment that is built to last.
What Does Phenolic Resin Mean?
Phenolic resins (PF) are a class of polymers that are among the most versatile ever devised. Despite the fact that they were created at the dawn of the polymer era, they continued to be developed into more and more uses. They are also regarded as the first polymeric goods commercially made from simple low-molecular-weight chemicals.
Phenolic resin is a synthetic resin made from the polymerization of phenol (C6H5OH) and formaldehyde (CH2C=O). Repeating units of –[(C6H3OH)-CH2]- with methylene (-CH2-) connections linking carbon sites to the phenolic hydroxide group make up the polymer (-OH).
Depending on the circumstances employed to manufacture the polymer, phenolic resins are phenolic novolac resins and phenolic resole resins. To harden phenolic novolac resins, they are further treated with a cross-linker.
Chemical and water stability are high in both types, as is temperature stability above 300°C or 572°F. Some phenolics can endure temperatures of up to 550°F. Condensation has proven to be a non-issue for many.
Phenolic resins can be considered the first commercially produced polymeric goods made from simple low-molecular-weight chemicals, as they were the first synthetic resins to be used at the time.
Phenolic resins are widely employed in the fabrication of circuit boards and are used in a variety of industrial items. These resins are commonly used to make billiard balls, chemically resistant worktops, circuit boards, and other panels due to their high hardness.
They can also be used for laminations and as a binding agent for items like brake pads. Coatings and adhesives are common uses for them as well.
Lightweight Composite Materials Processing
The phenolic resin contains p-t-Amylphenol, p-t-Butylphenol, p-Nonylphenol, mixed cresols, and cashew nutshell liquid and has low toxicity.
Phenolic resins are employed in structural composite materials because of their strong mechanical resistance, high heat resistance under load, and high impact resistance.
Because of their outstanding qualities and low cost, phenolic resins are commonly used to impregnate fiberglass, woven aramid, woven PBO (poly(p-Phenylene Benzobisoxazole)), and woven HMPE.
Phenolic Resins in Adhesive and Bonding Applications
In 1993, 916 million pounds of phenolic resins were sold in the adhesive and bonding industries—making this specific type of adhesive and bonding market the second largest outlet for phenolic resins.
The adhesive and bonding market may cover these applications because the phenolic resin is used as a bonding agent in composite wood and laminating applications.
In adhesive and bonding applications, phenolic resins include:
- Materials for insulating
- Wood that is fibrous and granular
- Shell molding and foundry
- Materials that cause friction
- Abrasives that are bonded and coated
Specialty Polymers and Polymer Processing
Adhesives made with phenolic resins and neoprene rubber have strong thermal stability or service temperatures up to 95°C and hardness.
The structure of the phenolic resin has been linked to adhesive qualities, particularly tack strength and peel strength.
The systems are available as toluene or MEK-based solutions or films. Although formulations that cure at ambient temperature are available, most adhesive films cure at 90°C to 250°C in 15 to 30 minutes.
Metal, wood, and polymers are all commonly bonded with them.
Composites
Phenolic resins are made from formaldehyde and phenol. Under acidic conditions, phenol reacts with less than equimolar amounts of formaldehyde to produce novolac resins, which contain aromatic phenol units linked mostly by methylene bridges.
Novolac resins are heat resistant and can be cross-linked with formaldehyde donors like hexamethylenetetramine to cure them. On the other hand, resoles are the most extensively used phenolic resins for composites.
They are essentially hydroxymethyl functional phenols or polynuclear phenols and are made by reacting phenol with a greater than the equimolar amount of formaldehyde under alkaline circumstances.
They are low-viscosity materials that are easier to process than novolacs. Other phenols, such as cresols or bisphenol, can also be used to make phenolic resins.
Cured phenolic resins are difficult to ignite because of their great thermal stability and charring tendency during the breakdown. Methane, acetone, carbon monoxide, propanol, and propane are the most common volatile breakdown products.
Additive and reactive flame retardants can be employed in a few circumstances when phenolic resins require flame retardant treatment. Some of the reactive flame retardants utilized in phenolics include tetrabromobisphenol A, different organic phosphorus compounds, halogenated phenols, and aldehydes—e.g., p-Bromobenzaldehyde.
In addition, flame retardants, chlorine compounds like chloroparaffins, and different thermally stable aromatic bromine compounds are used. Synergists such as antimony trioxide are also commonly used.
Phosphorus compounds that have been halogenated, such as tris(2-chloroethyl) phosphate (TRCP), halogenated organic polyphosphates, calcium, and ammonium phosphates, are all acceptable.
Zinc and barium compounds of boric acid, as well as aluminum hydroxide, are frequently used. Compounds like aluminum chloride, antimony trioxide, and organic amides are used to reduce the afterglow of phenolic resins.
Fiber-Reinforced Laminates in Aerospace Engineering
Phenolic resins are ideal for high-temperature applications requiring parts to meet fire safety requirements. Phenolic resins are used in a variety of applications, including electronics, ballistics, mine ventilation, offshore water pipe systems, aircraft, rail, and mass transit.
Key characteristics of phenolic resins include:
- Low density or weight-efficient
- Low thermal conductivity
- Excellent corrosion and chemical resistance
- Improved design flexibility
- Cost-effective production of complex 3D structures
- Excellent fatigue and impact properties
- Improved acoustic performance
- Radar or sonar transparency
- Low maintenance
Environmentally Assisted Fatigue
Phenolic resins are produced between phenols and aldehydes, yielding either novolacs or resoles.
These are then heated in the case of resoles or cross-linked with curing chemicals in the case of novolacs. This results in chains with a lot of aromatic rings, each of which has a phenol group linked to it.
Phenolic resins are generally less expensive than epoxies and polyimides, have a good temperature resistance, and are less flammable. Their biggest disadvantage is their low toughness, which limits their applications to those requiring high heat and combustion resistance.
Phenolic Resins in Advanced Fiber-Reinforced Polymer (FRP) Composites
When compared to alternative polymeric matrices for fire-resistance applications, phenolic resins have shown improved fire, smoke, and toxicity (FST) qualities. The FST qualities of phenolic resins are critical in determining which materials to use in a variety of applications.
No other matrix material has the same FST performance at a comparable price. The phenolic resin’s self-ignition temperature is around 600°C, and the limiting oxygen index is between 40% and 49%.
Phenolic composites are primarily employed in aviation for interior and mass transit like buses and trains industries—with interest in marine applications growing. Civil infrastructure, sporting items, and consumer products all use these composites on a regular basis.
When fire safety is the most important factor to consider when choosing building materials, phenolic composites have been the material of choice.
Phenolic composites do not support a flame due to the intrinsic qualities of the matrix, and when exposed to fire, they emit little or no smoke, which is less harmful than smoke produced by other composites, especially those containing specific halogenated flame retardants.
Flammability and Fire Resistance of Composites
Phenolic resins are made from formaldehyde and phenol. Under acidic conditions, phenol reacts with less than equimolar amounts of formaldehyde to produce so-called novolac resins, which contain aromatic phenol units linked mostly by methylene bridges.
Novolac resins are heat resistant and can be cross-linked with formaldehyde donors like hexamethylenetetramine to cure them. However, resoles made by reacting phenol with a greater than the equimolar quantity of formaldehyde under alkaline conditions—are the most extensively used phenolic resins for composites.
Resoles are hydroxymethyl functional phenols, also known as polynuclear phenols. They are low-viscosity materials that are easier to process than novolacs. Other phenols, such as cresols or bisphenols, can also be used to make phenolic resins.
Phenolics are particularly interesting in structural applications because of their intrinsic fire-resistance qualities, which result in limiting oxygen index (LOI) values of around 25, despite the fact that they tend to increase smoke generation. Because of the high level of inherent flame resistance, additional flame retarding is rarely required to achieve the required performance levels in composites.
Water and Phenolic Resins
However, their chief downsides are low toughness and a curing reaction that generates water. Water produced during curing can become trapped within the composite, and steam can be generated during a fire, causing harm to the material’s structure.
This evolution is supplemented chemically during the initial step of heat degradation, which could be due to phenol-phenol condensation. The released water aids in the oxidation of methylene groups to carbonyl bonds, which disintegrate further, releasing CO, CO2, and other volatile chemicals.
Water is not released until beyond 400°C in heavily cross-linked materials, and breakdown begins above 500°C. This was true for all of the phenolic resin samples tested by differential thermal analysis (DTA) and our own and others.
Flame Retardants and Phenolic Resins
Methane, acetone, carbon monoxide, propanol, and propane are the principal breakdown products, and the amount of char depends on the structure of phenol, initial cross-links, and tendency to cross-link during decomposition.
Additive and reactive flame retardants can be used to treat phenolic resin when it needs to become one. Some of the reactive flame retardants utilized in phenolics include tetrabromobisphenol A, different organic phosphorus compounds, halogenated phenols, and aldehydes like p-Bromobenzaldehyde.
Phosphorus can be added to the phenolic resin by a direct reaction with phosphorus oxychloride. Chemical reactions can also incorporate inorganic chemicals like boric acid into the phenolic resin.
As an additive flame retardant, chlorine compounds like chloroparaffins and different thermally stable aromatic bromine compounds can be used, and antimony trioxide is frequently added as a synergist. Halogenated phosphoric acid esters, such as tris(2-chloroethyl) phosphate, halogenated organic polyphosphates, calcium, and ammonium phosphates, are all suitable phosphorus compounds.
Zinc and barium compounds of boric acid, as well as aluminum hydroxide, are frequently used. Compounds like aluminum chloride, antimony trioxide, and organic amides are used to reduce the afterglow of phenolic resins.
Carbon Fiber Spinning
Other than activated carbon fibers (ACFs), phenolic resins can be used in a variety of applications. Circuit boards and molded items, such as laboratory counters and pool balls, as well as adhesives and coatings, friction linings, and oil well proppants, are the most common applications.
Versatile, inexpensive, heat and flame resistant, durable, strength and stiffness, low toxicity, and ease of processing are some of the fundamental qualities that have helped phenolic resin maintain its commercial viability. Apart from that, phenolics can be produced with superior acid, organic solvent, and water-resistant features to improve their properties.
The majority of phenolic-based CFs today are created from a phenol-formaldehyde thermosetting resin, which is made by combining phenol with formaldehyde in the presence of an acid catalyst.
The infusible fiber produced by formaldehyde curing a melt-spun novolac resin offers a 58% yield of CF at 700°C, with a carbon content of 94.5% and a strength of 0.69 GPa when heat treated in an inert atmosphere.
Heat treatment at 1800°C raises the carbon content to 99.96% while lowering the strength to 0.47 GPa. Clearly, phenolic resins as precursors for the production of CFs have been explored, but they have not been found to be commercially feasible.
Nonetheless, phenolic-based ACFs have a number of advantages over other ACFs and have gotten a lot of attention in the last two decades. To make ACFs, phenolic resins are melt-spun at a temperature over their softening point, stabilized with formaldehyde solution below the fibers’ melting point, carbonized at around 600°C, and then activated with carbon dioxide greater than 850°C or with steam less than 700°C as an oxidizing agent.
Shop with LabTech Supply Company for All of Your Lab Equipment Needs
Like any other business or institution, science labs and lab tables evolve with time, which makes it even more vital to update your lab equipment to stay up with the diverse requirements of science laboratories.
Durable tables are in great demand in all types of laboratories, but determining what these tables are built of and what materials to examine before making a purchase can be difficult.
Despite the challenges, lab tables made of phenolic resin continue to be the preferred choice of lab managers worldwide. Are you interested in learning more about lab tables made from phenolic resins?
At LabTech Supply Company, we understand that our customers want fresh and inventive solutions to keep their laboratory up to date with today’s technology.
That is why we are proud to be a recognized leader in laboratory benches, furniture, workstations, and storage equipment, and proud to be your one-stop store for anything lab tables and phenolic table tops related.
To find out more about our vast selection of laboratory equipment and discover how we can help you improve your laboratory’s work environment today, you can visit our website or contact us at LabTech Supply Company today!
